Lymphocytes Flashcards
What is Adaptive Immunity?
An immune response which is tailored to a specific pathogen - involves the expansion of antigen -specific lymphocytes which target the pathogen specifically and involve the formation of memory cells which provide longer lasting immunity
When is an adaptive immune response generated?
Once the pathogen overwhelms innate defense mechanisms
What major event occurs in the peripheral lymphoid organs/tissues to initiate the adaptive immune response
B or T lymphocytes encounter antigens for which their receptors have specific reactivity to
What is an antigen?
A molecules which is recognized by the highly specialized lymphocyte receptors, which act to induce an adaptive immune response
What are the two hallmarks of the adaptive immune response?
Highly specific and provide lasting immunity
How is diversity generated in the adaptive immune response?
Immunoglobulin gene rearrangement - each BCR chain is encoded by separate multi gene clusters on different chromosome, and during B cell maturation, these gene segments are rearranged and brought together
What are the chains of the BCR receptor?
Kappa, lambda and heavy chain
Where does B cell Maturation occur?
In the bone marrow
What are some problems with the random process of gene reassortment to generate the high number of BCRs we need.
Autoimmunity - producing BCRs and TCRs that complement your own self antigens
What is immunological memory?
Where memory lymphocytes exist in the blood that are able to recognize and bind to the same antigen upon subsequent infections and therefore induce an immune response
What are characteristics of a a secondary immune response?
Faster and must larger response
What are the two primary cells involved in the adaptive immune response and which response are they involved in?
T cells = Cell Mediated Reponse
B cells = Humoral / Antibody Reponse
What are the differences between B cells and T cells?
T cells mature in thymus, B cells in bone marrow
T cells have CD4 and CD8 receptors, B cells have different one
T cells do not produce antibodies, B cells do
B cells need to be activated by T cells to function
B cells tend to stay outside of lymph nodes eg in Peyers Patches, T cells inside lymph nodes
What are the three kinds of T cells?
Regulatory, helper, killer
What happens when an antigen binds to a TCR?
The cell proliferates and differentiates into one of three functional types of effector T cells: Cytotoxic (killer), helper or regulatory
What are cytotoxic T cells?
The kill other cells that are infected with viruses or intracellular pathogens that bear the specific antigen
What do helper T cells do?
They provide signals, normally in the forms of cytokines which activate the functions of other cells, like B cells to produce antibodies w
What do regulatory T cells do?
They suppress the activity of other Lymphocytes and help to limit the possible damage due to immune response
Which CD do T helper cells have?
CD 4
Which CD do T Killer Cells have?
CD 8
What are T Helper Cell 1 (Th1) classified by?
Production of Interferon-gamma, Tumour Necrosis Factor, Interleukin 12
What are Th1 involves in?
B cell class switching, macrophages and inflammation
What are T Help Cell 2 characterized by?
Production of Interleukin 4, 5 and 13
What do Th2 do?
are involved in the B cell class switching to produce IgE for allergic reactions and parasitic infections (ALLERGY AND WORMS)
What are Th17 involved in?
Neutrophil responses which help to clear bacteria and fungi
What do TfH do? t follicular helper cell
B cell support
What do Tregs produce?
IL-10