An antigen is any substance that causes your immune system to produce antibodies against it. This means your immune system does not recognize the substance, and is trying to fight it off. An antigen may be a substance from th
What is antigen
What is epitope & paratope?
Classification of antigen
Pro antigen
Superantigens
Antigenicity
Determinants of antigenicity
Test for antigen detection
توثيق مراجع البحث العلمي على أنو: "إثبات ادلصادر البيانات وادلعلومات ونسبها إىلnedalalazzwy
عترب البحث العلمي ادلمنهج ذاك الذي يستويف يف مجيع مراحلو مراعاة معايري البحث العلمي ادلنهجي
خاصة فيما خيص األمانة يف اعتماد ادلراجع سواء كانت دراسات سابقة او مراجع لبعض االقتباسلت والعبارات
وزبتلف عملية التوثيق للمراجع باختالف مصدرىا ونوعها واختالف رلال زبصصها فتوثيق التت ملال خيتلف
عنو يف توثيق ادلقاالت الصحفية وخيتلف عن توثيق ادلواد االلتًتونية وىذه األخرية خيتلف يف توثيقها تبعا ألنواعها
ىي األخرى واذلدف من ذلك ىو حفاظ الباحث على سهولة العودة اىل ادلصادر وادلراجع ادلستخدمة بالنسبة
لقراء حبقو العلمي وىو أيضا من باب األمانة العلمية
A single nucleotide polymorphism (abbreviated SNP, pronounced snip) is a genomic variant at a single base position in the DNA. Scientists study if and how SNPs in a genome influence health, disease, drug response and other traits.
What is antigen
What is epitope & paratope?
Classification of antigen
Pro antigen
Superantigens
Antigenicity
Determinants of antigenicity
Test for antigen detection
توثيق مراجع البحث العلمي على أنو: "إثبات ادلصادر البيانات وادلعلومات ونسبها إىلnedalalazzwy
عترب البحث العلمي ادلمنهج ذاك الذي يستويف يف مجيع مراحلو مراعاة معايري البحث العلمي ادلنهجي
خاصة فيما خيص األمانة يف اعتماد ادلراجع سواء كانت دراسات سابقة او مراجع لبعض االقتباسلت والعبارات
وزبتلف عملية التوثيق للمراجع باختالف مصدرىا ونوعها واختالف رلال زبصصها فتوثيق التت ملال خيتلف
عنو يف توثيق ادلقاالت الصحفية وخيتلف عن توثيق ادلواد االلتًتونية وىذه األخرية خيتلف يف توثيقها تبعا ألنواعها
ىي األخرى واذلدف من ذلك ىو حفاظ الباحث على سهولة العودة اىل ادلصادر وادلراجع ادلستخدمة بالنسبة
لقراء حبقو العلمي وىو أيضا من باب األمانة العلمية
A single nucleotide polymorphism (abbreviated SNP, pronounced snip) is a genomic variant at a single base position in the DNA. Scientists study if and how SNPs in a genome influence health, disease, drug response and other traits.
Mycology is the branch of biology concerned with the study of fungi, including their genetic and biochemical properties, their taxonomy and their use to humans, including as a source for tinder, traditional medicine, food, and entheogens, as well as their dangers, such as toxicity or infection.
Rabies virus, scientific name Rabies lyssavirus, is a neurotropic virus that causes rabies in humans and animals. Rabies transmission can occur through the saliva of animals and less commonly through contact with human saliva. Rabies lyssavirus, like many rhabdoviruses, has an extremely wide host range.
Immunofluorescence (IF) is a technique that permits visualization of virtually many components in any given tissue or cell type. This broad capability is achieved through combinations of specific antibodies tagged with fluorophores. Consequently, the pos
fastidious organism is any organism that has complex or particular nutritional requirements. In other words, a fastidious organism will only grow when specific nutrients are included in its medium.
Multiplex PCR is a technique whereby PCR is used to amplify several different DNA sequences simultaneously. It is a type of target enrichment approach. It was first described in 1988 as a method to detect deletion mutations in the dystrophin gene – the largest known human gene
Radio Immuno Assay, Immuno Fluorescent Test, Lab 4.pptxnedalalazzwy
A RIA is a very sensitive in vitro assay technique used to measure concentrations of substances, usually measuring antigen concentrations (for example, hormone .
What is enzyme-linked immunosorbent assay?
A laboratory technique that uses antibodies linked to enzymes to detect and measure the amount of a substance in a solution, such as serum. The test is done using a solid surface to which the antibodies and other molecules stick.
Infectious diseases can be viral, bacterial, parasitic or fungal infections. There's also a rare group of infectious diseases known as transmissible spongiform encephalopathies (TSEs).
Classification of medical parasitology Lec.2.pptxnedalalazzwy
Parasitology is the scientific discipline concerned with the study of the biology of parasites and parasitic diseases, including the distribution, biochemistry, physiology, molecular biology, ecology, evolution and clinical aspects of parasites, including the host response to these agents.
What is toxoplasmosis? Toxoplasmosis is an infection caused by a single-celled parasite called Toxoplasma gondii. While the parasite is found throughout the world, more than 40 million people in the United States may be infected with the Toxoplasma parasite.
Integrons are genetic elements that contain a site-specific recombination system able to integrate, express and exchange specific DNA elements, called gene cassettes. 5. The complete integron is not considered to be a mobile element as such as it lacks functions for self-mobility.
Mycoplasma pneumoniae are bacteria that can cause illness by damaging the lining of the respiratory system (throat, lungs, windpipe). People can have the bacteria in their nose or throat at one time or another without being ill. People spread Mycoplasma pneumoniae bacteria to others by coughing or sneezing.
A microarray is a laboratory tool used to detect the expression of thousands of genes at the same time. DNA microarrays are microscope slides that are printed with thousands of tiny spots in defined positions, with each spot containing a known DNA sequence or gene.
Cloning is a technique scientists use to make exact genetic copies of living things. Genes, cells, tissues, and even whole animals can all be cloned. Some clones already exist in nature. Single-celled organisms like bacteria make exact copies of themselves each time they reproduce.
A cell cycle is a series of events that takes place in a cell as it grows and divides. A cell spends most of its time in what is called interphase, and during this time it grows, replicates its chromosomes, and prepares for cell division. The cell then leaves interphase, undergoes mitosis, and completes its division.
Polymerase chain reaction (abbreviated PCR) is a laboratory technique for rapidly producing (amplifying) millions to billions of copies of a specific segment of DNA, which can then be studied in greater detail.
Assay of sodium hydroxide solution.pptxnedalalazzwy
sodium hydroxide is useful for its ability to alter fats. It is used to make soap and as a main ingredient in household products such as liquid drain cleaners. Sodium hydroxide is usually sold in pure form as white pellets or as a solution in water.
Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
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.
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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.
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
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Acute scrotum is a general term referring to an emergency condition affecting the contents or the wall of the scrotum.
There are a number of conditions that present acutely, predominantly with pain and/or swelling
A careful and detailed history and examination, and in some cases, investigations allow differentiation between these diagnoses. A prompt diagnosis is essential as the patient may require urgent surgical intervention
Testicular torsion refers to twisting of the spermatic cord, causing ischaemia of the testicle.
Testicular torsion results from inadequate fixation of the testis to the tunica vaginalis producing ischemia from reduced arterial inflow and venous outflow obstruction.
The prevalence of testicular torsion in adult patients hospitalized with acute scrotal pain is approximately 25 to 50 percent
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
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Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
As flu season approaches, health officials in Bangalore, Karnataka, are urging residents to get their flu vaccinations. The seasonal flu, while common, can lead to severe health complications, particularly for vulnerable populations such as young children, the elderly, and those with underlying health conditions.
Dr. Vidisha Kumari, a leading epidemiologist in Bangalore, emphasizes the importance of getting vaccinated. "The flu vaccine is our best defense against the influenza virus. It not only protects individuals but also helps prevent the spread of the virus in our communities," he says.
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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.
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
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- Prix Galien International Awards Ceremony
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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
2. The ‘traditional’ definition of antigen is a substance that
may stimulate B and/or T cells and react with the products
of that response, including immunoglobulin antibodies,
and/or specific receptors on T cells.
Immunogenicity
Is the ability to induce a humoral and/or cell mediated
(specific) immune response.
All immunogens are antigens, but not all Antigens are
immunogens.
3. Alloantigen is an antigen present in some members or
strains of a species, but not in others.
Alloantigen include blood group substances on erythrocytes
and histocompatibility antigens present in grafted tissues
4. Haptens
Haptens, small organic molecules that are antigenic but not
immunogenic.
Carrier: is Chemical coupling of a hapten to a large protein
yield an immunogenic hapten-carrier conjugate.
It is the basis of allergic responses to drugs such as penicillin.
5. Antigenic determinant
Epitopes are the immunologically active regions of an
immunogens that bind to antigen-specific membrane
receptors on lymphocytes or to secreted antibodies.
6. ANTIGENIC DETERMINANTS:
A. Determinants recognized by B cells
are small and are limited to approximately 4-8 residues.
(amino acids and or sugars).
are either:
primary sequence residues))Linear
Conformational(secondary, tertiary or quaternary)
B. Determinants recognized by T cells:
are limited to approximately 8-15 residues
Only primary sequence residues
8. Epitopes
• In protein antigens epitopes can be defined in terms
of:
– Amino acid composition
– Protein location
– Length (5-15 amino acids)
• epitopes:
• Immunodominant
– Epitopes bound by a greater proportion of antibodies
than others in a normal in vivo immune response
– Also known as Major Antigenic Sites
• Sequestered
• Epitopes can be divided into 2 classes:
– Discontinuous epitopes
– Continuous (linear) epitopes
10. Types of Peptide Epitope
LinearB cell Epitope
Antibody or “B cell” Epitope
Conformational
Non-Conformational
Class II MHCs
Professional Antigen
Presenting cells
Foreign proteins
8-20 amino acids
Class I MHCs
all cells
Foreign and self proteins
8-10 amino acids
T cell Epitope
Epitope
11. B cells can recognize linear or conformational epitopes on cell surfaces, of proteins, of
carbohydrates or of lipids. The B cell antigen receptor is a form of membrane Ig.
T cells recognize linear peptide fragments bound to MHC class I or class II molecules.
T cells and B cells use Distinct Antigen Receptors
to Recognize Fundamentally Different Forms of Antigen
12. Properties of Epitopes
• They occur on the surface of the protein and are more
flexible than the rest of the protein.
• They have high degree of exposure to the solvent.
• The amino acids making the epitope are usually charged and
hydrophilic.
13. Antigen-specific membrane receptors
Membrane molecules or receptors that responsible for
antigen recognition by the immune system are:
1. Membrane-bound antibodies on B cells
2. T-cell receptors
3. Class I MHC molecules
4. Class II MHC molecules
18. Chemical nature o Antigens
Lipids
Proteins
Carbohydrates
Nucleic Acids
19. Substances that act as antigens:
Microbial structures:
Such as bacterial and fungal cell walls, protozoan cell
membranes, bacterial and fungal capsules, microbial
flagella, bacterial pili, viral capsids, viral envelope-
associated glycoproteins , etc.
microbial toxins.
Allergens
The body's own cells that the body fails to recognize as
"normal self” such as cancer cells, infected cells, cells
involved in autoimmune diseases.
20. Factors influencing immune response of Ag
Antigen Properties
1.Foreigness:
The immune system normally discriminates between self and non-self
such that only foreign molecules are immunogenic.
2.Chemical properties of Ag
Chemical nature
Proteins>Polysaccharides >Nucleic Acids >Lipids
0
21. Factors influencing immune response of Ag
Antigen Properties
3.Molecule weight (size)
reasonable large molecule( >10.0 kd) has good immuogenecity.
– more stationary
– more surface structure for lymphocyte to recognize
22. Factors influencing immune response of Ag
Antigen Properties
4. Complexity of Ag structure
ring > linear
aromatic ring
23. 5. Conformation and accessibility
6. Physical states :
Polymer > monomer
Particulate > Soluble
Denatured > Native
7.Degradability
Antigens that are easily phagocytosed are
generally more immunogenic.
Factors influencing immune response
of Ag
Antigen Properties
24. Factors influencing immune response of Ag
Body Factors
Genetics, Species: Some substances are
immunogenic in one species but not in another.
Similarly, some substances are immunogenic in
one individual but not in others (i.e. responders
and non responders).
MHC
Individual :Age, health, etc.
Age can also influence immunogenicity, usually the very young
and the very old have a diminished ability to mount and
immune response in response to an immunogen.
25. Factors influencing immune response of Ag
Method of Administration
1. Genotype
Influences, MHC, T and B cell
receptors, etc…
2.Immunogen dosage
– Too small – no response
– Too large – tolerance
– Boosters – repeated
dosages
•
3. Routes of dministration
26. Biological Influences on Immunogenicity
• Adjuvants-Enhance immunogenicity
– Potential mechanism
• Ag persistence
• Cell signaling or cytokine effect
• Induction of inflammation
• Lymphocyte stimulation
• Change the chemical and physical charactes of Ag
• Improves the Ag process and presentation ability of
macrophages
• stimulates proliferation of lymphocytes
Types
• Biological adjuvant:BCG,LPS
• Synthesized adjuvant
Freund’s incomplete adjuvant
Freund’s complete adjuvant
• Chemical adjuvant : Alum
27. 1. Binding and uptake of antigen
– depends on the physical state of the antigen
and the cell type involved.
2. Antigen processing
– MHC class I processing pathway
– MHC class II processing pathway
3. Antigen presentation
Susceptibility to Antigen
Processing & Presentation
28. Cross reaction
• Reaction between the same Ab and different Ag
with same similar determinants.
• Mechanism of cross reaction:
- Common Ag determinant
- Similar structure of Ag determinant
• Significance:
Because there are some common antigen
determinants between different microbes, so the
antiserum against one kind of Ag can also react
with another Ag and couse a cross reaction .
29. Antigen Presenting Cells (APCs)
A group of immune cells, whose role is to take
up, process and present antigenic peptides to T
cells.
First internalize antigen, either by Phagocytosis
or by endocytosis, and then display a part of that
antigen on their membrane bound to a class II
MHC molecule.
Except for the B cell, APCs are non specific
30. • Professional APC
– Macrophages, dendritic cells, and B cells, which
can express MHC class II molecules.
• Non-professional APC
– Other cell type capable of expressing MHC class II
molecules
eg. Endothelial cells, EC
Fibroblasts
Activated T cell
33. 2) Source, distribution and classification
• Source
DC are bone marrow-derived
– Myeloid DC
– Lymphoid DC
34. • Distribution and classification
DCs are found in many organs throughout the
body
– DC in lymphoid tissue
• Interdigitating cell, IDC
• Follicular DC, FDC
• thymic dendritic cell, TDC
– DC not in lymphoid tissue
• Langerhans cells
• Interstitial DC
– DC in body fluid
• Veiled cells
• Peripheral blood DC
36. Antigen-presenting cells
APC
Macrophage T cell via MHC antigen
Dendritic cells T cell via MHC antigen
B cells T cell via antigen captrue by
surface antibody and MHC
antigen
Activated T cells T cell via MHC antigen
37. EXOGENOUS ANTIGENS
Antigen that enters the body of the organism from the
outside, e.g. through inhalation, ingestion, or injection.
The immune system's response to exogenous antigens
is often subclinical. By endocytosis or phagocytosis,
Endocytosis is a process by which cells absorb
molecules (such as proteins) by engulfing them.
41. Two antigen-processing pathways
MHC class I MHC class II
Major antigen
sources
endogenous
antigen
exogenous antigen
Processing
machinery
proteasome lysosomal
enzymes
Cell type where
active
all nucleated cells professional APCs
Site of antigen-
MHC binding
endoplasmic
reticulum
lysosome and
endosome
MHC utilized MHC class I MHC class II
Presents to CD8+ T cell (Tc) CD4+ T cells (Th)
42. Endogenous Antigen
• Antigen that is produced from within the cell
as part of normal cell metabolism or when the
cell is infected by bacteria or viruses.
• Endogenous antigens include xenogenic
(heterologous), autologous and idiotypic or
allogenic (homologous) antigens.
44. Autoantigen
An autoantigen is usually a normal protein or complex of
proteins (and sometimes DNA or RNA) .
Is an endogenous antigen that stimulates the production
of autoantibodies.
45. Tumor antigens
Tumor antigen is an antigenic substance produced in
tumor cells.
Classification of tumor antigens:
Tumor-Specific Antigens (TSA), which are present only
on tumor cells and not on any other cell .
Tumor-Associated Antigens (TAA), which are present on
some tumor cells and also some normal cells.
46. Superantigens
Superantigens (SAgs) are a substance (as an enterotoxin) that
acts as an antigen capable of stimulating much larger numbers
of T cells than an ordinary antigen.
SAgs are produced by some pathogenic viruses and bacteria
most likely as a defense mechanism against the immune syste
Example: Staphylococcal enterotoxins (food poisoning),
Staphylococcal toxic shock toxin (toxic shock syndrome),
Staphylococcal exfoliating toxins (scalded skin syndrome) and
Streptococcal pyrogenic exotoxins (shock).