This document provides an overview of the cells of the immune response. It describes the origin of immune cells from stem cells in the bone marrow and thymus. The main cells discussed are lymphocytes, including T cells which develop in the thymus and have T cell receptors, and B cells which develop in the bone marrow and have antibody receptors. The roles and subsets of T cells such as helper T cells, cytotoxic T cells, regulatory T cells, and memory T cells are summarized. The maturation and antigen-dependent selection of B cells into plasma cells that secrete antibodies is also outlined.
Introduction
History
Types of immunity
Tissues of immunity
Cells of immunity
Basic aspects of immunology
Major histocompatibility complex
Cytokines
Disorders of immune system
Immune responses in periodontal pathogenesis
Periodontal vaccine
Host modulation
Conclusion
References
introduction of adaptive immunity. classification of adaptive immunity, factor affecting it and mechanism of adaptive immunity comparison between adaptive immunity and innate immunity. characteristic of adaptive immunity . cell mediated immune responses immunoglobulins
types of immunoglobulins. functions of immunoglobulins, hypersensitivity reactions
Introduction
History
Types of immunity
Tissues of immunity
Cells of immunity
Basic aspects of immunology
Major histocompatibility complex
Cytokines
Disorders of immune system
Immune responses in periodontal pathogenesis
Periodontal vaccine
Host modulation
Conclusion
References
introduction of adaptive immunity. classification of adaptive immunity, factor affecting it and mechanism of adaptive immunity comparison between adaptive immunity and innate immunity. characteristic of adaptive immunity . cell mediated immune responses immunoglobulins
types of immunoglobulins. functions of immunoglobulins, hypersensitivity reactions
Antigen processing and presentation by Dr K.Geetha, Associate Professor, Department of Biotechnology, Kamaraj College of Engineering & Technology, Near Virudhunagar, Madurai Dist.
B Cell Receptor & Antibody Production-Dr C R MeeraMeera C R
Antibody production is the function of B lymphocytes. These slides describe the structure of B cell receptor and steps involved in antibody production by B lymphocytes
T-Cell Activation
• Concept of immune response
• T cell-mediated immune response
• B cell-mediated immune response
I. Concept of immune response
• A collective and coordinated response to the introduction of foreign substances in an individual mediated by the cells and molecules in the immune system.
II. T cell-mediated immune response
• Cell-mediated immunity is the arm of the adaptive immune response whose role is to combat infection of intracellular pathogens, such as intracellular bacteria (mycobacteria, listeria monocytogens), viruses, protozoa, etc.
This presentation gives you the detailed description of various cells & organs of immune systems that participates (particularly, in combination), make communication between themselves to regulate the whole immune system very precisely.
By DR. MANPREET KAUR BEHL.
Description of classificaton of immune system, immune cells, HLA, MHC complexes, antigen presentation, t-cell responses and b-cell responses, antibody, isotype switching, hypersenstivity reactions etc.
Antigen processing and presentation by Dr K.Geetha, Associate Professor, Department of Biotechnology, Kamaraj College of Engineering & Technology, Near Virudhunagar, Madurai Dist.
B Cell Receptor & Antibody Production-Dr C R MeeraMeera C R
Antibody production is the function of B lymphocytes. These slides describe the structure of B cell receptor and steps involved in antibody production by B lymphocytes
T-Cell Activation
• Concept of immune response
• T cell-mediated immune response
• B cell-mediated immune response
I. Concept of immune response
• A collective and coordinated response to the introduction of foreign substances in an individual mediated by the cells and molecules in the immune system.
II. T cell-mediated immune response
• Cell-mediated immunity is the arm of the adaptive immune response whose role is to combat infection of intracellular pathogens, such as intracellular bacteria (mycobacteria, listeria monocytogens), viruses, protozoa, etc.
This presentation gives you the detailed description of various cells & organs of immune systems that participates (particularly, in combination), make communication between themselves to regulate the whole immune system very precisely.
By DR. MANPREET KAUR BEHL.
Description of classificaton of immune system, immune cells, HLA, MHC complexes, antigen presentation, t-cell responses and b-cell responses, antibody, isotype switching, hypersenstivity reactions etc.
Describes the basic properties and mechanisms of T cells and B cells in maintaining Immune Response against foreign antigens or infections and covers the UG and PG portion of immunology.
THIS SEMINAR HAS BRIEF ABOUT T CELLS , TYPES, FUNCTIONS, CLUSTER OF DIFFERENTIATION, MHC MOLECULE, TOLERANCE , ROLE OF T CELLS IN PROGRESSION AND PREVENTION, T CELL IMMUNODEFICIENCY DISORDERS
New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
MANAGEMENT OF ATRIOVENTRICULAR CONDUCTION BLOCK.pdfJim Jacob Roy
Cardiac conduction defects can occur due to various causes.
Atrioventricular conduction blocks ( AV blocks ) are classified into 3 types.
This document describes the acute management of AV block.
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
Pulmonary Thromboembolism - etilogy, types, medical- Surgical and nursing man...VarunMahajani
Disruption of blood supply to lung alveoli due to blockage of one or more pulmonary blood vessels is called as Pulmonary thromboembolism. In this presentation we will discuss its causes, types and its management in depth.
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
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Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...
Cells of immune response
1. AL-AZHAR UNIVERSITY
FACULTY OF MEDICINE FOR GIRLS
MICROBIOLOGY DEPARTMENT
CELLS OF IMMUNE RESPONSE
THE SILENT ARMY OF THE BODY
Under the supervision of
PROF.DR:ASMAA ELGENDY
DR:HANAN
3. الرحيم الرحمن هللا بسم
Points described in this research:
A. An overview of the immune system.
B. Components of the immune system.
C. Origin of immune cells.
D. Lymphocytes.
E. Granulocytes.
F. Phagocytic cells.
4. IMMUNOLOGY
is the science that studies immune system.
The main function of the immune system is to
prevent or limit infections by microorganisms such as bacteria, viruses,
fungi, and parasites.
First line
intact skin and mucus membrane.
Second line
innate immunity :it can function immediately upon
entry of the microorganisms and it is not specific.
Third line
it takes several days to become fully functional
and it is highly specific.
6. CELLS OF IMMUNE RESPONSE
Origin of the immune cells:
- During embryonic development, blood cell
precursors originate mainly in the fetal liver and yolk
sac.
-in postnatal life, the stem cells reside in the bone
marrow.
Then stem cells differentiate as the next figure:
8. A. LYMPHOCYTES:
The lymphocytes occupy a very special place among
the leukocytes that participate in one way or another in
immune reactions due to their ability to interact
specifically with antigenic substances and to react to
nonself antigenic determinants.
Lymphocytes differentiate from stem cells in the fetal
liver, bone marrow, and thymus into two main functional
classes T and B.
Their classification based on site of differentiation and
on receptors:
-T cells and naturall killers T - in thymus -
(TCR)
-B cells – bone marrow - (BCR)
(no cell surface specific receptors – NK cells)
They are found in the peripheral blood and in all
lymphoid tissues.
9. 1.T LYMPHOCYTES:
most important players of specific immunity.
T lymphocytes have a longer lifespan than B
lymphocytes. Long-lasting lymphocytes are particularly
important because of their involvement on
immunological memory.
Contain surface receptors :
1)CD (cluster of differentiation) proteins-
molecules on the cells membrane, allow the
identification of cells.
2)TCR- receptor for antigen.
3)MHC gp I or II class.
10. 1)CD PROTEINS:
allow an identification of T-cell subsets
CD 3 = important in intracellular signaling to initiate
an immune response; closely associated with TCR.
CD 4,8 = are expresed on subclasses of mature T
cells; CD4 reacts with MHC gp II.class),CD8 reacts
with MHC gp I. class on macrophages.
CD 28- receptor for costimulator molecules CD80
and 86.
11. 2)TCR RECEPTORS:
Antigen receptors are encoded by several gene
segments that recombine during lymphocyte
maturation.
Heterodimer consisting of 2 nonidentical
polypeptide chains linked together by disulfide
bonds.
TCR heterodimer is noncovalently associated with
the γ,δ,ε chains of the CD3 molecule.
COMPLEX TCR- CD3 makes contact with both the
Ag and MHC gp.
12. FUNCTION OF T LYMPHOCYTE:
1) regulation of immune responses and various
effector functions (cytotoxicity and lymphokine
production being the main ones) that are the
basis of cell-mediated immunity (CMI).
2) carry an antigen-recognition unit on their
membranes, known as T-cell receptors.
3) Several subpopulations of T lymphocytes with
separate functions will be dicussed later.
13. SURFACE RECEPTORS OF T LYMPHOCYTE:
All T cells contain CD3 and TCR.
T cells are subdivided into two major categories on
the basis of whether they have CD4 or CD8
proteins on their surface. Mature T cells have either
CD4 or CD8 proteins but not both.
14. CD4 T cells: CD8 T cells:
1) 2/3 of all T cells containging CD3
2) CD4 cell surface molecule
– recognise part of MHC II
molecule that is not part
of peptid binding site
3) Functionally – helper
1) 1/3 of all T cells containing CD3
2) CD8 cell surface molecule
– recognise part of MHC I
molecule that is not designated
to bind peptids
3) Functionally :
Tc cytotoxic – eliminate virus
or i.c.bacteria infected cells
Ts supreesor – increase and
control reactions of specific
immunity
15. T CELL SUBPOPULATIONS:
Subpopulations of T cells have been defined
according to their particular function and their CD
membrane markers.
They are:
1) Helper:CD4 (T helper 1 and T helper 2).
2) Cytotoxic:CD8.
3) Regulatory.
4) Memory.
16. 1) T HELPER(CD4):
recognize the epitopes in association with class II
MHC
help B cells to produce antibodies and help
phagocytes to destroy ingested microbes
subsets of Th cells: Th1, Th2 cells in the next table:
17. a) T helper 1 b) T helper 2
secrete:
1)INF-γ (gamma interferon) : activates
macrophages to become more effective at
killing phagocytosed microbes, supresses
the development of Th2 cells.
2)IL- 2 : stimulates survival and
proliferation of T cells, called T-cell growth
factor.
3)TNF (tumor necrosis factor)- stimulates
the recruitment of neutrophils and
monocytes to sites of infection, activates
these cells to eradicate microbes.
4)IL-3 : promotes expansion of immature
marrow progenitors of all blood cells.
5)GM-CSF : acts on progenitors in the
bone marrow to increase production of
neutrophils and monocytes.
Th1 based immune reaction:
1)Th1 cells stimulate phagocytes to
eliminate ingested microbes.
2)Interferon gamma is the main Th1
cytokine.
secrete:
1)IL-4 : induces differentiation of Th2
cells from naive CD4+ precursors,
stimulation of IgE production by B cells.
2)IL-5 : activates mast cells.
3)IL-6 : stimulates the synthesis of
acute phase proteins by hepatocytes.
4)IL-10 : inhibits activated
macrophages, supresses Th1
production.
5)IL-3, GM-CSF.
Th2 based immune reaction:
1)Th 2 response provide help for B
cells and are essential for antibody-
mediated immunity.
2)Antibodies are needed to control
extracellular pathogens.
3)The Th2 - type cytokines include IL
4, 5, and 13.
18. 2)T CYTOTOXIC (CD8):
cause lysis of target cells; are active against
tumors, virus-infected cells, transplanted allogenetic
tissue
release TNF- depresses proteosynthesis
recognize the foreign epitope in association with
class I MHC molecules
destroy their target cells by releasing perforin
(create poresin the cell membrane and cytoplasm
escapes) and granzymes (degrading essential
macromolecules)
19. 3)T REGULATORY:
Express CD4, CD25, FoxP3.
Regulate the activation or effector function of other
T cells.
Are necessary to maintain tolerance to self
antigens.
20. 4)T MEMORY:
Memory T cells, as the name implies, endow our host
defenses with the ability to respond rapidly and vigorously for
many years after the initial exposure to a microbe or other
foreign material.
This memory response to a specific antigen is due to several
features:
(1) many memory cells are produced, so that the secondary
response is greater than the primary response, in which very few
cells respond.
(2) memory cells live for many years or have the capacity to
reproduce themselves.
(3) memory cells are activated by smaller amounts of antigen
and require less costimulation than do naïve, unactivated T cells.
(4) activated memory cells produce greater amounts of
interleukins than do naïve T cells when they are first activated.
21. 2.B LYMPHOCYTES:
Origin:
1) During embryogenesis, B-cell precursors are
recognized first in the fetal liver.
2) they migrate to the bone marrow, which is their main
location during adult life. Unlike T cells, they do not
require the thymus for maturation.
3) Pre-B cells lack surface immunoglobulins and light
chains but do have heavy chains in the cytoplasm.
4) The maturation of B cells has two phases:
a) the antigen-independent phase consists of stem
cells, pre-B cells, and B cells.
b) the antigen-dependent phase consists of the cells
that arise subsequent to the interaction of antigen with the
B cells.
23. FUNCTION OF B LYMPHOCYTES:
1) interact with antigenic epitopes, using their
immunoglobulin receptors.
2) subsequently develop into plasma cells, secreting
large amounts of specific antibody.
3) circulate as memory cells.
4) present antigenic peptides to T cells, consequent
upon interiorization and processing of the original
antigen.
24. CLONAL SELECTION OF B LYMPHOCYTES:
clonal selection, accounts for antibody formation.
Each individual has a large pool of B lymphocytes (about 107).
Each immunologically responsive B cell bears a surface
receptor (either IgM or IgD) that can react with one antigen (or
closely related group of antigens); i.e., there are about 107
different specificities.
An antigen interacts with the B lymphocyte that shows the best
"fit" with its immunoglobulin surface receptor. After the antigen
binds, the B cell is stimulated to proliferate and form a clone of
cells. These selected B cells soon become plasma cells and
secrete antibody specific for the antigen.
25. Plasma cells synthesize the immunoglobulins with the same antigenic
specificity (i.e., they have the same heavy chain and the same light chain) as
those carried by the selected B cell.
* Immature B cells express IgM receptors on the surface
* Mature B cells express IgM, IgD molecules on surfaces
* IgM and IgD molecules serve as receptors for antigens
* Memory B-cells express IgG or IgA or IgE on the surface
* B-cells bear receptors for Fc portion of IgG and a receptor for C3 component
of the complement
* They express an array of molecules on their surfaces that are important in
B-cells interactions with other cells such as MHC II, B7 and CD40
27. • THE END RESULT OF ACTIVATION OF B LYMPHOCYTE IS:
1)Plasma cells 2)Memory cells
Most activated B cells form plasma
cells.
produce large amounts of
immunoglobulins specific for the
epitope.
secrete thousands of antibody
molecules per second for a few days
and then die.
Some activated B cells form memory
cells.
can remain quiescent for long periods
but are capable of being activated
rapidly upon reexposure to antigen.
Most memory B cells have surface IgG
that serves as the antigen receptor, but
some have IgM.
The presence of these cells explains
the rapid appearance of antibody in the
secondary response.
Memory T cells secrete interleukins
that enhance antibody production by
the memory B cells.
28. 3.NATURAL KILLER CELL:
Large granular lymphocytes which lack most surface markers of B
and T-cells
* They comprise 5-10% of the peripheral lymphocytes
They are called "natural" killer cells because they are active
without prior exposure to the virus, are not enhanced by exposure,
and are not specific for any virus.
* They function mainly in innate immunity
* They have spontaneous non-specific cytotoxic activity on virus
infected cells, tumour cells and graft cells by secreting cytotoxins
(perforins and granzymes) similar to those of cytotoxic T
lymphocytes and by participating in Fas-Fas ligand-mediated
apoptosis.
* They are not MHC restricted and MHC I inhibits their killing
functions
29. NATURAL KILLER CELL:
They can kill without antibody, but antibody (IgG) enhances
their effectiveness, a process called antibody-dependent
cellular cytotoxicity (ADCC). IL-12 and gamma interferon are
potent activators of NK cells.
• Lack T-cell receptor, CD3 proteins, and surface IgM
and IgD
Thymus not required for development
• Normal numbers in Severe Combined
Immunodeficiency Disease (SCID) patients
• Activity not enhanced by prior exposure
30. B. GRANULOCYTES:
Granulocytes are a collection of white blood cells
with segmented or lobulated nuclei and granules in
their cytoplasm, which are visible with special
stains.
Because of their segmented nuclei, which assume
variable sizes and shapes, these cells are
generically designated as polymorphonuclear
neutrophil leukocytes (PMN).
31. CLASSIFICATION:
•Classified according to cell morphology and cytoplasmic
staining
•Neutrophils: stains with BOTH acid and basic dyes
called ‘PMN’ for lobed nucleus; 50% of circ
leukocytes
•Eosinophils: stain with ACID dye (Eosin-red);
bilobed nucleus;1-3% of leuko’s
•Basophils: stain with BASIC dye (Methylene blue);
<1% of leuko’s
32. 1.NEUTROPHILS:
• Circulate in peripheral blood 7-10 hr before migrating into tissue;
live only a few days.
• very important component of our innate host defenses, and
severe bacterial infections occur if they are too few in number
(neutropenia) or are deficient in function, as in chronic
granulomatous disease.
• increased # (leukocytosis) used as an indicator of infection
• extravasate in inflam rxn
• attracted by chemotactic factors
• Use both O2-dep and O2-indep digestive mech’s
• Produce high levels of defensins
granules are lysosomes, which contain a variety of
degradative enzymes that are important in the
bactericidal action of these cells.
33. Neutrophils have receptors for IgG on their surface so
IgG is the only immunoglobulin that opsonizes, i.e.,
makes bacteria more easily phagocytosed. Note that
neutrophils do not display class II MHC proteins on their
surface and therefore do not present antigen to helper T
cells. This is in contrast to macrophages that are also
phagocytes but do present antigen to helper T cells.
Neutrophils can be thought of as a "two-edged" sword.
The positive edge of the sword is their powerful
microbicidal activity, but the negative edge is the tissue
damage caused by the release of degradative enzymes.
An excellent example of the latter is the damage to the
glomeruli in acute post-streptococcal glomerulonephritis.
The damage is caused by enzymes released by
neutrophils attracted to the glomeruli by C5a activated by
the antigen–antibody complexes deposited on the
glomerular membrane.
34. 2.ESINOPHILS:
are white blood cells with cytoplasmic granules that
appear red when stained with Wright stain. The red
color is caused by the negatively charged eosin dye
binding to the positively charged major basic
protein in the granules.
The eosinophil count is elevated in two medically
important types of diseases: parasitic diseases,
especially those caused by nematodes and
hypersensitivity diseases, such as asthma and
serum sickness. Diseases caused by protozoa are
typically not characterized by eosinophilia.
35. • The function of eosinophils has not been clearly established. It seems
likely that their main function is to defend against the migratory larvae of
nematodes, such as Strongyloides and Trichinella. They attach to the
surface of the larvae and discharge the contents of their granules, which
in turn damages the cuticle of the larvae. Attachment to the larvae is
mediated by receptors on the eosinophil surface for the Fc portion of the
heavy chain of IgG and IgE.
• Another function of eosinophils may be to mitigate the effects of
immediate hypersensitivity reactions because the granules of eosinophils
contain histaminase, an enzyme that degrades histamine, which is an
important mediator of immediate reactions. However, the granules of the
eosinophils also contain leukotrienes and peroxidases, which can
damage tissue and cause inflammation. The granules also contain major
basic protein that damages respiratory epithelium and contributes to the
pathogenesis of asthma.
• Eosinophils can phagocytose bacteria but they do so weakly and are not
sufficient to protect against pyogenic bacterial infections in neutropenic
patients. Although they can phagocytose, they do not present antigen to
helper T cells. The growth and differentiation of eosinophils is stimulated
by interleukin-5.
36. 3.BASOPHILS AND MAST CELLS:
Basophils are white blood cells with cytoplasmic
granules that appear blue when stained with Wright
stain. The blue color is caused by the positively charged
methylene blue dye binding to several negatively
charged molecules in the granules. Basophils circulate
in the bloodstream, whereas mast cells, which are
similar to basophils in many ways, are fixed in tissue,
especially under the skin and in the mucosa of the
respiratory and gastrointestinal tracts.
Basophils and mast cells have receptors on their
surface for the Fc portion of the heavy chain of IgE.
When adjacent IgE molecules are cross-linked by
antigen, immunologically active mediators, such as
histamine, and enzymes, such as peroxidases and
hydrolases, are released. These cause inflammation
and, when produced in large amounts, cause severe
immediate hypersensitivity reactions such as
systemic anaphylaxis.
37. Mast cells also play an important role in the innate
response to bacteria and viruses. The surface of mast
cells contain Toll-like receptors that recognize bacteria
and viruses. The mast cells respond by releasing
cytokines and enzymes from their granules that mediate
inflammation and attract neutrophils and dendritic cells
to the site of infection. Dendritic cells are important
antigen-presenting cells that initiate the adaptive
response. The role of mast cells in inflammation has
been demonstrated in rheumatoid arthritis. These cells
produce both inflammatory cytokines and the enzymes
that degrade the cartilage in the joints.
39. 1.MACROPHAGE :
2.MONOCYTE:
Monocytes and macrophages are believed to be
closely related.
The monocyte is considered a leukocyte in transit
through the blood, which when fixed in a tissue will
become a macrophage.
Monocytes and macrophages, as well as
granulocytes are able to ingest particulate matter
(microorganisms, cells, inert particles) and for this
reason are said to have phagocytic functions.
The phagocytic activity is greater in macrophages
(particularly after activation by soluble mediators
released during immune responses) than in
monocytes
40. • Macrophages, monocytes, and related cells play an important role in the
inductive stages of the immune response by processing complex antigens
and concentrating antigen fragments on the cell membrane. In this form,
the antigen is recognized by helper T lymphocytes For this reason, these
cells are known
as antigen-presenting cells (APC).
• APC include other cells sharing certain functional properties with
monocytes and macrophages present in skin (langerhans cells), kidney,
brain
(microglia), capillary walls, and lymphoid tissues.
• Langerhans cells can migrate to the lymph nodes, where they interact with
T lymphocytes and assume the morphological characteristics
of dendritic cells(will discussed later).
• All antigen-presenting cells express one special class of histocompatibility
antigens,designated as class II MHC or la (I region–associated) antigens.
• The expression of MHC-II molecules is essential for the interaction with
helper T lymphocytes.
• Antigen-presenting cells also release cytokines, which assist the
proliferation of antigenstimulated lymphocytes, including interleukins (IL)-1,
-6, and -12.
41. MECHANISMS OF MACROPHAGE FUNCTION:
function mechanism
Phagocytosi
s
Ingestion and killing of microbes in phagolysosomes. Killing caused
by reactive oxygen intermediates such as superoxides, reactive
nitrogen intermediates such as nitric oxide, and lysosomal enzymes
such as proteases, nucleases, and lysozyme.
Antigen
presentation
Presentation of antigen in association with class II MHC proteins to
CD4-positive helper T cells. Also displays B7 protein, which acts as a
costimulator of helper T cells.
Cytokine
production
Synthesis and release of cytokines such as IL-1 and TNF, and
chemokines such as IL-8.
42. 3.DENDRETIC CELLS:
are a third type of cell that function as "professional" antigen-
presenting cells (macrophages and B cells are the other two); i.e.,
they express class II MHC proteins and present antigen to CD4-
positive T cells.
They are particularly important because they are the main inducers
of the primary antibody response.
The name "dendritic" describes their many long, narrow processes
(that resemble neuronal dendrites), which make them very efficient at
making contact with foreign material.
Dendritic cells are primarily located under the skin and the mucosa,
e.g., Langerhans' cells in the skin.
Dendritic cells migrate from their peripheral location under the skin
and mucosa to local lymph nodes, where they present antigen to
helper T cells.
4 types: Langerhans, Interstitial DC’s, Myeloid DC’s, Lymphoid DC’s.
major role as APC to TH.
43. MATURATION OF DENDERTIC CELLS:
Loss of endocytic and phagocytic receptors
Increased expression of MHC
Up -regulation of co-stimulatory molecules (CD80
and CD86) required for T-cell stimulation
Up-regulation of CD40 and adhesion molecules
ICAM-1 and LFA-3
Fc receptors (endocytosis) decrease.
45. FOLLICULAR DENDERITIC CELLS:
monocyte-derived cell.
have a similar appearance to the dendritic cells but are quite
different from them in their location and function.
Follicular dendritic cells (FDCs) are located in the B-cell-containing
germinal centers of the follicles in the spleen and lymph nodes.
They do not present antigen to helper T cells because they do not
produce class II MHC proteins. Rather, they capture antigen–
antibody complexes via Fc receptors located on their surface.
The antigen–antibody complexes are then detected by activated B
cells.
The antibody produced by these B cells undergoes affinity
maturation. (Affinity maturation is the improvement in the affinity of
an antibody for the antigen that occurs upon repeated exposure to
the antigen.).
In addition, FDCs produce chemokines that attract B cells to the
follicles in the spleen and lymph nodes.
46. REFERENCES:
A) Medical Immunology Fifth Edition,
edited by: Gabriel Virella ,Medical University of South
Carolina .Charleston, South Carolina.
B) Cellular and molecular immunology by:Abul K.
Abbas and Andrew H. Lichtman.
C) W.W.W.
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