Peptide vaccine containing only epitopes capable of inducing positive, desirable T cell and B cell mediated immune response.
Peptides‖ used in these vaccines are 20–30 amino acid sequences that are synthesized to form an immunogenic peptide molecule representing the specific epitope of an antigen.
sufficient for activation of the appropriate cellular and humoral responses
Eliminating allergenic and/or reactogenic responses.
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.
B cell Activation by T Independent & T Dependent Antigens-Dr C R MeeraMeera C R
During humoral immune response, Ab production is brought about by B lymphocytes. Based on the ability to induce Ab formation, antigens can be classified into T independent and T dependent antigens. Some antigens can directly induce the B cells to produce the Abs and are called T Independent Ans. However, some Ans require the help of T lymohocytes for the production of Abs from B cells. These Ans are called T Dependent Ans.
Peptide vaccine containing only epitopes capable of inducing positive, desirable T cell and B cell mediated immune response.
Peptides‖ used in these vaccines are 20–30 amino acid sequences that are synthesized to form an immunogenic peptide molecule representing the specific epitope of an antigen.
sufficient for activation of the appropriate cellular and humoral responses
Eliminating allergenic and/or reactogenic responses.
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.
B cell Activation by T Independent & T Dependent Antigens-Dr C R MeeraMeera C R
During humoral immune response, Ab production is brought about by B lymphocytes. Based on the ability to induce Ab formation, antigens can be classified into T independent and T dependent antigens. Some antigens can directly induce the B cells to produce the Abs and are called T Independent Ans. However, some Ans require the help of T lymohocytes for the production of Abs from B cells. These Ans are called T Dependent Ans.
T cell cloning, cloning of alloreactive human t cells, Antigen recognition by...varun yadav
cloning conditions, media used, cloning conditions, characterization of T cell clones, role of mhc 2 and antigens in T cell cloning, applications of T cell cloning in vaccine development.
Developing vaccines against infectious and epidemic diseases with the aid of Bioinformatics is now possible, by predicting epitopes on an antigen and finding possible targets for the antibody to bind. A new era of vaccine production is just ahead of us.
Watch out the ppt to know more!!!
Altering the specificity of T cell receptor (TCR) is one of the popular strategies to genetically modify T cells to enhance the tumor-killing activity of T cells. From a tumor-reactive T cell or active anti-tumor T-cell antigens, the appropriate target sequence is introduced to modify T cells to target a broad range of tumors with improved specificity. https://www.creative-biolabs.com/car-t/cellrapeutics-tcr-technology.htm
A detailed description of Cell mediated immunity and antibody mediated immunity. Lecture notes for medical, dental and paramedical undergraduate students.
T cell cloning, cloning of alloreactive human t cells, Antigen recognition by...varun yadav
cloning conditions, media used, cloning conditions, characterization of T cell clones, role of mhc 2 and antigens in T cell cloning, applications of T cell cloning in vaccine development.
Developing vaccines against infectious and epidemic diseases with the aid of Bioinformatics is now possible, by predicting epitopes on an antigen and finding possible targets for the antibody to bind. A new era of vaccine production is just ahead of us.
Watch out the ppt to know more!!!
Altering the specificity of T cell receptor (TCR) is one of the popular strategies to genetically modify T cells to enhance the tumor-killing activity of T cells. From a tumor-reactive T cell or active anti-tumor T-cell antigens, the appropriate target sequence is introduced to modify T cells to target a broad range of tumors with improved specificity. https://www.creative-biolabs.com/car-t/cellrapeutics-tcr-technology.htm
A detailed description of Cell mediated immunity and antibody mediated immunity. Lecture notes for medical, dental and paramedical undergraduate students.
T cells are one of the important white blood cells of the immune system and play a central role in the adaptive immune response and are distinguished from other lymphocytes by the presence of a T-cell receptor (TCR) on their cell surface.
B cells, also known as B lymphocytes, are a type of white blood cell of the lymphocyte subtype. They function in the humoral immunity component of the adaptive immune system.. B cells produce antibody molecules.
In mammals, B cells mature in the bone marrow, which is at the core of most bones. In birds, B cells mature in the bursa of Fabricus.
B cells present antigens (they are also classified as professional antigen-presenting cells (APCs)) and secrete cytokines.
The MMR vaccine is a combination vaccine used against three viruses..pdfpreetamsahu17
The MMR vaccine is a combination vaccine used against three viruses. Our bodies develop
immunity through a series of steps that result in the activation of cvtotoxic cells against virally-
infected cells. Place the following steps for T cell activation in the correct order.
-Dendritic cells infected with the virus migrate to lymph nodes
- A cytoxic T cell binds to MHC-I protein of an infected dendretic cell
- A helper T cell binds to MHC-II protein of an infected dendretic cell
- The dendretic cell secrete IL-12 to differentiate the helper T cell into a type 1 helper cell
- the type 1 helper cell secretes IL-2 to activate the cytotoxic T cell
- activated cytotoxic T cell self stimulate and leave the lymph node
- activated cytoxic t cella undergo clonal expansion
-Dendritic cells infected with the virus migrate to lymph nodes
- A cytoxic T cell binds to MHC-I protein of an infected dendretic cell
- A helper T cell binds to MHC-II protein of an infected dendretic cell
- The dendretic cell secrete IL-12 to differentiate the helper T cell into a type 1 helper cell
- the type 1 helper cell secretes IL-2 to activate the cytotoxic T cell
- activated cytotoxic T cell self stimulate and leave the lymph node
- activated cytoxic t cella undergo clonal expansion Solve the Problem: Rights va
Responsibitities (2) 4 ot 10 The thaR vaccine is a combination vaccine used against three viruses,
Our bodles develop immunity through a series ef steps that resuit in the acsivatsh of ngtebexic T
celis agahnt virady-infected cells. Place the following stepe for T cell activation in the correct
order. Parsor.
The general objectives of involving the public at different stages in the EIA process were considered by a recent European Commission research project (EC, 1999) as given in the table.
European union is composed of several hundred countries including Muslim nations like Turkey, Albania etc. So, if one gets access into nation like Poland or Romania, he gets access throughout Europe.
Objectives of public participation during stages of the EIA process
Formal opportunities for public participation in EIA are defined in legislation. While rights of involvement in many countries are limited to opportunities for viewing and commenting on finalised reports, in principle, public consultation and participation can occur at every stage in the EIA process. The table summarizes the main objectives of public involvement at each stage of the EIA process, including a detailed description of these objectives (EC, 1999).
In brief, literature shows that there are a number of advantages of involving the public early on in the EIA process. If participation does occur early on then interaction between the public, developer and decision-making body should continue throughout the EIA process if the full benefits are to be seen.
Table : Summary of Objectives of Public Involvement in EIA
Stage of EIA process Objectives of public involvement
Screening
Identification of significant impacts
Scoping
• Identification of public's interest and values
• Identification of priorities for assessment
• Encouraging public understanding of the proposed project
Assessment
• The public can contribute local knowledge and values to the prediction, evaluation and mitigation of impacts
• Improvement in quality and acceptability of EIA report
EIA Report Review
Public contribute to evaluation of quality and acceptability of report
Decision
Public comment on acceptability of project impacts
Monitoring
Public evaluate impacts that occur and support project environmental management process
There is an international agency called Environmental Protection Agency EPA. EPA forms and implements regulations regarding making the environment better.
We are at present in a very critical state as far as the situation of global warming and receding snowcaps in the Antarctica. It has been found that there is a hole in the Ozone layer due to increasing level of pollution throughout the world.
The rising sea-levels are threatening the global community. Moreover, the increasing amount of garbage thrown into the seas is a major problem now for countries like Canada. How to manage this sort of problems is equally challenging in both the developed and underdeveloped nations.
6. Solution mitigation of climate change.pptxNeeraj Ojha
There is an international agency called Environmental Protection Agency EPA. EPA forms and implements regulations regarding making the environment better.
We are at present in a very critical state as far as the situation of global warming and receding snowcaps in the Antarctia. It has been found that there is a hole in the Ozone layer due to increasing level of pollution throughout the world.
5.Climate change and its impact on environment.pptxNeeraj Ojha
There is an international agency called Environmental Protection Agency EPA. EPA forms and implements regulations regarding making the environment better.
We are at present in a very critical state as far as the situation of global warming and receding snowcaps in the Antarctia. It has been found that there is a hole in the Ozone layer due to increasing level of pollution throughout the world.
4BDirect and indirect health effects of climate change.pptxNeeraj Ojha
As far as Nepalese people are concerned, they are very bad in their food habits. Disease like ulcer and diabetes are rampant along Nepalese people. Moreover, there are areas in the country where there is a severe malnutrition.
Factors influencing food habits
•Individual Preferences
Every individual has unique likes and dislikes concerning foods.
•Cultural Influences
A cultural group provides guidelines regarding acceptable foods, food combinations, eating patterns, and eating behaviors.
•Social Influences
Members of asocial group depend on each other, share a common culture, and influence each other's behaviors and values.
As far as Nepalese people are concerned, they are very bad in their food habits. Disease like ulcer and diabetes are rampant along Nepalese people. Moreover, there are areas in the country where there is a severe malnutrition.
Factors influencing food habits
•Individual Preferences
Every individual has unique likes and dislikes concerning foods.
•Cultural Influences
A cultural group provides guidelines regarding acceptable foods, food combinations, eating patterns, and eating behaviors.
•Social Influences
Members of asocial group depend on each other, share a common culture, and influence each other's behaviors and values.
2,3 Greenhouse gases, global scenario, green house effectt and global warming...Neeraj Ojha
As far as Nepalese people are concerned, they are very bad in their food habits. Disease like ulcer and diabetes are rampant along Nepalese people. Moreover, there are areas in the country where there is a severe malnutrition.
Factors influencing food habits
•Individual Preferences
Every individual has unique likes and dislikes concerning foods.
•Cultural Influences
A cultural group provides guidelines regarding acceptable foods, food combinations, eating patterns, and eating behaviors.
•Social Influences
Members of asocial group depend on each other, share a common culture, and influence each other's behaviors and values.
8.1Determinants of Adaptive Capacity.pptxNeeraj Ojha
There is an international agency called Environmental Protection Agency EPA. EPA forms and implements regulations regarding making the environment better.
We are at present in a very critical state as far as the situation of global warming and receding snowcaps in the Antarctia. It has been found that there is a hole in the Ozone layer due to increasing level of pollution throughout the world.
The rising sea-levels are threatening the global community. Moreover, the increasing amount of garbages thrown into the seas is a major problem now for countries like Canada. How to manage this sort of problems is equally challenging in both the developed and underdeveloped nations.
There is an international agency called Environmental Protection Agency EPA. EPA forms and implements regulations regarding making the environment better.
We are at present in a very critical state as far as the situation of global warming and receding snowcaps in the Antarctia. It has been found that there is a hole in the Ozone layer due to increasing level of pollution throughout the world.
The rising sea-levels are threatening the global community. Moreover, the increasing amount of garbages thrown into the seas is a major problem now for countries like Canada. How to manage this sort of problems is equally challenging in both the developed and underdeveloped nations.
4A Socio-economic and environmental impacts of climate change.pptxNeeraj Ojha
As far as Nepalese people are concerned, they are very bad in their food habits. Disease like ulcer and diabetes are rampant along Nepalese people. Moreover, there are areas in the country where there is a severe malnutrition.
Factors influencing food habits
•Individual Preferences
Every individual has unique likes and dislikes concerning foods.
•Cultural Influences
A cultural group provides guidelines regarding acceptable foods, food combinations, eating patterns, and eating behaviors.
•Social Influences
Members of asocial group depend on each other, share a common culture, and influence each other's behaviors and values.
Eating disorders are complex, bio-psycho-social conditions, with multiple causes. Eating disorders arise from a combination of established social, psychological, biological, and interpersonal factors. While they may begin with preoccupations with food and weight, they are most often about much more than food. It is important to understand that the factors that contribute to eating disorders are complex and multifaceted; they are not simply about weight and they are certainly not choices.
अमेरिकामा नेपाली मामिलामा सीबीआईको अनुसन्धान
https://cib.nepalpolice.gov.np/
पछिल्लो समय अमेरिकाको मूलधारको राजनीतिमा नेपाली मूलका थोरै मानिसहरु प्रवेश गर्न सफल भएका छन् । मेरिल्याण्डका प्राध्यापक ह्यारी भण्डारी( Harry Bhandari, Maryland) डेमोक्रेटिक ककसमा प्रवेश गरेका छन् । त्यस्तै दर्शन रौनियार (Darshan Rauniyar, California) अमेरिकी सिनेटमा उम्मेदवार बनेका छन् । उहाँसँग धेरै सहयोग र पैसा भए पनि, एक नाबालिगद्वारा बलात्कारको आरोपमा उहाँलाई ककसमा अवरुद्ध गरियो।
अमेरिकामा प्रचण्ड र कम्युनिस्ट साम्राज्य न्यूयोर्कदेखि टेक्साससम्म फैलिएको छ । उनीहरुले पासाङ लामा, कुन्ती थापा, श्रुति कंसाकार(Euless Texas), सिर्जना मुनिकार(Jerseycity, NJ) , साङ शेर्पा(Construction), विजय पौडेल (Journalism) लगायत अमेरिकामा रहेका आफ्ना एजेन्ट र व्यक्तिसँग चन्दा उठाएर अर्बौं डलरको पैसा लुटेका छन् । श्रीलंकाको तमिल टाइगर्स र भारतीय माओवादीहरू: अष्ट्रेलिया, अमेरिका, युनाइटेड किंगडम र क्यानडा जस्ता विकसित राष्ट्रहरूमा तिनीहरूको धेरै ठूलो सञ्चालन छ।बालकुमारीमा बस्ने माधव नेपालजस्ता मानिसहरूलाई यी कम्युनिष्ट डन र गुण्डाहरूले धेरै रक्षा गर्न सक्छन्। धेरै कांग्रेसका कार्यकर्ताहरू प्रलोभनमा पारेर अमेरिकामा पैसा लुट्दै हत्या वा आत्महत्या जस्तो देखिने गरी हत्या हुन्छ। प्रचण्डको कारबाही क्लिन्टन फाउण्डेशन (Clinton Foundation) , वर्तमान राष्ट्रपति बाइडेन र अमेरिकामा सक्रिय जासुससँग जोडिएको छ ।
चिनियाँहरूले क्वीन्समा 5339 97st कोरोना, NY जस्ता धेरै घरहरू ल्याएका छन् जहाँ उनीहरूले कांग्रेस र राप्रपा कार्यकर्ताहरूलाई प्रलोभनमा पारेका छन् र उनीहरूलाई संयुक्त राज्यको डेमोक्रेटिक पार्टीको सहयोगमा थुनेका छन्। अमेरिकामा धेरै वरिष्ठ राजतन्त्र समर्थक र पूर्व सेना सदस्यहरू(eg. Bishwa Bahadur Shah, Bishal Bikram Shah, Kamala Prasai ) यस तरिकाले मारिएका छन् वा विषाक्त छन्। रञ्जित थापा र बुद्ध बस्ताकोटी जस्ता पूर्वप्रहरी पनि यी अपरेशनमा संलग्न रहेको पाइएको छ ।
यो समग्र परिदृश्यलाई हेर्दा पछिल्लो समयको विकासको सन्दर्भमा नेपालको संविधानमा परिवर्तन र संशोधन गर्नुपर्ने आवश्यकता पनि हामीले देखेका छौं । हामीले लामो समयदेखि अल्पसंख्यक जनसंख्या र गे-लेस्बियन-ट्रान्सजेन्डर (LGBT) समुदायको शक्तिलाई बेवास्ता गर्दै आएका छौं। यही कारणले उनीहरू विदेशी शक्तिसँग गठबन्धन गर्दै राष्ट्रिय सुरक्षाका (national security) लागि खतरा बनिरहेका छन् । विशेषगरी इजरायल जस्ता देशमा सिआइएको कारबाही विश्वका लागि खतरा बन्दै गएको छ । सीआईएको इजरायल राष्ट्रमा ठूलो भूमिगत आणविक सुविधा (underground nuclear weapon facility) छ जुन हाम्रो देशको धेरै नजिक छ। यसको मतलब यो हो कि सानो द्वन्द्वको अवस्थामा सीआईएले(CIA) आफ्नो आणविक शक्ति सिधै नेपालमा घुमाउन सक्छ। तसर्थ, हामी आजदेखि नै होसियार हुनुपर्दछ र अन्य सहयोगीहरूलाई पनि त्यस्तै गर्न चेतावनी दिनु पर्छ।
लिन्डन बी जोनसनले जेएफकेको (JFK) हत्यामा इटालियन माफिया (Organized Crime ) सँग सहयोग गरेको भनिन्छ। माफियाहरूले आफ्नो व्यापार र प्रभाव बढाउन तत्कालीन कम्युनिस्ट भियतनामसँग युद्ध गर्न चाहन्थे। ठ्याक्कै परिस्थिति अहिले हामीले सामना गरिरहेका छौं। अमेरिकाको लुटेरा टोली हाम्रो राष्ट्रसँग युद्ध चाहन्छ र उनीहरूले बाइडेन प्रशासनलाई भारतसँग मिलेर राजधानी काठमाडौंमा आक्रमण गर्न बाध्य पारिरहेका छन् । मोदी सरकारले सधैं नेपाललाई आफ्नो क्षेत्रको रूपमा हावी गर्न खोजेको छ। यसै कारण मनमोहन सिंहको प्रधानमन्त्र
PHG 481 Traditional Systems of Medicine BPHARM syllabus PUNeeraj Ojha
Traditional system of Medicine includes Chinese medicine, Ayurveda, Tibetan medicine, Kampo, Homeopathy etc. Answers are derived from teacher's notes and internet
Pht 402 Clinical Pharmacy questions answered OLD IS GOLDNeeraj Ojha
These Q/A's are based upon the syllabus by Pokhara University based in the city of Pokhara, Nepal. Hope this will be helpful to the beginners in the schools of pharmacy.
Piccola Cucina is regarded as the best restaurant in Brooklyn and as the best Italian restaurant in NYC. We offer authentic Italian cuisine with a Sicilian touch that elevates the entire fine dining experience. We’re the first result when someone searches for where to eat in Brooklyn or the best restaurant near me.
At Taste Of Middle East, we believe that food is not just about satisfying hunger, it's about experiencing different cultures and traditions. Our restaurant concept is based on selecting famous dishes from Iran, Turkey, Afghanistan, and other Arabic countries to give our customers an authentic taste of the Middle East
Roti Bank Hyderabad: A Beacon of Hope and NourishmentRoti Bank
One of the top cities of India, Hyderabad is the capital of Telangana and home to some of the biggest companies. But the other aspect of the city is a huge chunk of population that is even deprived of the food and shelter. There are many people in Hyderabad that are not having access to
Ang Chong Yi Navigating Singaporean Flavors: A Journey from Cultural Heritage...Ang Chong Yi
In the heart of Singapore, where tradition meets modernity, He embarks on a culinary adventure that transcends borders. His mission? Ang Chong Yi Exploring the Cultural Heritage and Identity in Singaporean Cuisine. To explore the rich tapestry of flavours that define Singaporean cuisine while embracing innovative plant-based approaches. Join us as we follow his footsteps through bustling markets, hidden hawker stalls, and vibrant street corners.
Key Features of The Italian Restaurants.pdfmenafilo317
Filomena, a renowned Italian restaurant, is renowned for its authentic cuisine, warm environment, and exceptional service. Recognized for its homemade pasta, traditional dishes, and extensive wine selection, we provide a true taste of Italy. Its commitment to quality ingredients and classic recipes has made it a adored dining destination for Italian food enthusiasts.
1. Activation and proliferating of B cell
The maturation of B cells into antibody producing
plasma cells can be divided into two phases. An
antigen independent phase followed by an antigen
dependent phase.
1.Antigen independent phase of B cell activation:
T- independent ag do not require T-cell help when
these antigen bind to the surface receptor(Ig) of B
cells both signal 1 and 2 come from the binding by
polymeric structure and the B cell transfer into
plasma cell for producing antibodies. These antigen
cant activate mature B cell but only naïve or
immature B cells.
2. 2.T- dependent antigen mediated B cell activation:
•B cell activation requires two signals and the help of
CD4 T-cells in case of T-dependent antigens.
•T cell and B cell contact with surface and only then
activation and proliferation of B cell occurs.
•The mechanism of B cell acivation and proliferation is
rather complex than that of T cell independent
antigen.
•At first T-dependent antigen binds to the surface Ig of
B cells.
•After binding,the B cell membrane engulf the bound T
dependent antigen by endocytosis mechanism.
•After internalization of antigen and binding antibody,B
cell enzymes degrade the T dependent antigen into
several peptides.
3. •After that MHC II proteins starts to synthesize and at the
same time,the expression of co-stimulatory protein B7 is
also enhanced.
•After this MHC II peptide complex is expressed on the
membrane as antigen presentation.
•The circulating CD4 T cell recognized the antigen
presentation by MHC II molecule on B cell surface.
•And then the CD28 molecule on the T helper cell binds to
the B7 molecule of B cell.
•The binding of B7-CD28 provides a co-stimulatory signal
for T cells to synthesize CD40 ligand which binds with the
CD40 of B cell and this interlinks provides signal-2 for the
activation of B cells.
•All these bindings brings B and T cells very close and
membrane contact and B cell then starts to produce
surface receptors for various cytokines.
4. •The T cells then synthesizes various types of cytokines
that brings various changes to B cells,and these changes
transform B cell into plasma cell,formation of memory B
cell and class switching of B cell.
5. Cytokines
It is a soluble protein which is secreted by the
monocytes,activated lymphocytes,fibroblast which functions
as mediators for immune and inflammatory reactions.
In innate immunity, cytokines are produced by the
macrophages and NK cells and in adaptive immunity
cytokines are produced by T lymphocytes.
Some of cytokines are as follows:
Interleukins:Synthesized by T lymphocytes and leucocytes.
Interleukins 1:produced by activated macrophages,
Interleukins 2:Produced by activated CD4 T cells which
converts naïve T cells into Th1 and also produced by
macrophages.
Interleukin 4-produced by activated CD4 T cells which
converts naïve T cell into TH2.
6. Interferon: It is specific to viral infection and are of two
types:
Type I interferon(IFN-α ,IFN-ß):It increases expression of
class I MHC and activates NK cells.
Type II(IFN-ƴ):It activates the macrophages.
Tumor necrosis factor:It is a cytokine produced by
activated macrophages that functions to recruitment
the neutrophils and monocytes to the site of infection
and destroy the microbes.
Chemokines: Low molecular weight cytokines that
stimulates the movement of leucocytes and regulate
migration of leucocytes from blood to
tissue(chemotaxis activation).
7. T cells: During the immune response, T cells have
extremely important role of creating cellular immunity.
There are two types of T cells
I. Helper T cells(CD4 cells)which serve as helper cells for
other lymphocytes,phagocytes and natural killer cells.
II. The cytotoxic T cells (CD8 T cells) which specialize in
identifying and killing tumor cells and cells infected with
viruses or other micro organisms.
Activation of CD4 T cells: The activation of CD4 T cells
occurs also in the secondary lymphoid tissues.This is
accomplished when a complex consisting of a class II
MHC protein carrying a peptide of foreign antigen which
are expressed on the surface of APC.
8.
9. 1. Fragmentation of antigen and presentation by class II
MHC molecule: Exogenous antigens such as pathogenic
micro organisms when enter the secondary lymphoid
tissue or carried to the tissue by macrophages, Peptides
fragments which are engulfed and digest binds to a cleft
in a MHC II.
2. Recognition of MHC II molecules bound with ag by CD4
T cells: When the TCR recognizes the class II MHC-
peptides complex,the CD4 molecules binds to MHC II
molecules.
• The cell surface protein(co-stimulatory signals)
provided by interaction of CD28 on the T-cell and B7 on
the APC,activates the CD4 T cells.
• CD4 cells can be divided into two major types:type
1(Th-1) and type 2(Th-2) helper cells.
10. •The naïve CD4 T cells is initially termed as Th-0 cell which
has the potential to develop into Th-1 cell or Th-2 cell
depending upon the cytokine present.
•If a Th-0 cell is exposed to IFN-ƴ from NK cells and IL-2
produced by macrophages,the Th-0 become Th-1 cell, the
activator of cell mediated immunity.
•The Th-1 cell stimulates itself to secrete IL-2 and IL-2 can
also activate the cytotoxic T cells.
•In addition,Th-1 cell produce the cytokine IFN-ƴ which
enhances the ability of APC to increase the expression of
class II MHC and B7 proteins.This results in the
presentation of increasing numbers of antigen peptides to
CD4 T cells, thus enhancing the immune response and
become memory cells which can be rapidly activated to
secondary immune response.
11. •If Th-0 cells are exposed to IL-4 produced by specialized
subset of CD4 T cells,the Th-0 cells become TH-2 cells.
•TH-2 cells express a cell surface protein,CD-40 ligand and
secrete IL-4,5,6.These proteins are required to activate B
cells which eventually become antibody producing plasma
cell, leading to humoral immunity.
12.
13. Activation of CD8 T cells:
•The activation of CD8 T cells enhances when the peptide
is presented by MHC class I molecules on APC and results
in the generation of cytotoxic T-cells which participate in
killing foreign cells.
•Activated CD8 T cells produce IFN-ƴ, tumor necrosis
factor and additional cytokines (IL-2).
•When antigen peptides bind to MHC I molecules and
are presented to surface of the infected cells then CD8 T
cell with appropriate TCR recognizes antigen fragments
class I MHC complex on surface.
•The co stimulatory signal necessary for full activation of
the cytotoxic T cell is either IL-2 secreted by TH-1 cell or
the interaction of CD28 present on T cell with B7 present
on APC cell.
14. The activated CD8 T cells (cytotoxic T cell) kill target cell
by:
•Induction of osmotic lysis: Cytotoxic substances
produced during CD8 T cell activation are released on the
surface of target cells by exocytosis. Substances include
perforins which forms channels and high concentraion of
perforins cause influx of water and leakage of cell
contents leading to death of cell.
•Induction of apoptosis: Here cytotoxic T cell makes the
target cell “commit suicide”by degrading its DNA.This is
accomplished by low concentration of perforins that form
a limited number of pores through which proteases
(Granzymes)can pass. These enzymes induce the target
cells own apoptotic pathway.Granzymes are responsible
for DNA fragmentation.