Adaptive Immunity Flashcards
why is adaptive immunity effective in addressing infection or disease
adaptive immunity has memory
specific memory allows the immune system to respond quickly with a second exposure
describe the role of antigens and antigen specificity in adaptive immunity
antigens are the basis to the immune response
- antigen proteins provide a recognition site for foreign objects, epitopes
two arms of the adaptive immune response
humoral immunity:
-b cells
-extracellular targets
-antibodies secreted into the serum
-binds to targets and directs effector responses
cell-mediated immunity:
-t cells
-intracellular antigens
-eliminates infected or damaged cell
-helps B cell and T cells function
differentiate between T-helper and cytotoxic T cells according to their surface markers and functions
-CD4+ T Helper cells: help B cells and cytotoxic T cells provide antigen specific responses
-CD8+ cytotoxic T cells: interact directly with damaged (viral infected) cells and perform cell killing
role of lymphatics in adaptive immune development and memory
-lymphatic system returns lymph back to circulation into the blood
-lymph nodes sample antigens from the lymphatics and display to lymphocytes (secondary lymphoid tissue)
-naive lymphocytes (untrained) bump into antigens and APCs to be trained then released into the blood
how do dendritic cells and T helper cells interact
reacts with APCs
-CD4+ T helper cells recognize antigen from antigen
-help activate B cells to proliferate and generate antibody diversity
-help coordinate other immune cells to perform useful effector function
types of T helper cells
-Th1 = cell mediated immunity
-Th2 = humoral immunity
-Treg = resolution of response
role of T helper cells in effector cell development and activation
coordinates other immune cells
T cell receptor
-T cells have a specific receptor (TCR)
-developed from antigen exposure in the lymph node
-the variable region changes to achieve specific protein binding
-interact with Human Leukocyte Antigen (HLA)
difference between HLA class 1 and HLA class 2 and the immune responses they are involved in
HLA Class I- intracellular antigens
-expressed on all nucleated cells
-recognized by CD8+ cytotoxic T cells
-antigens derived from within the cell (viruses, intracellular bacteria, cancerous cells)
HLA Class II- extracellular antigens
-only expressed on Antigen Presenting Cells (APC): B cells, Macrophages, Dendritic cells
-recognized by CD4+ T helper cells
-could be any endocytosed protein
define B cells and their primary effector mechanism
-generate antibodies specific to an antigen
-B cell receptor (BCR) is a membrane bound antibody
-activated B cells can differentiate into plasma cells that secrete large quantities of soluble antibodies (immunoglobulins)
-membrane-bound form (BCR), secreted form (antibody)
activation of B cells
-triggered when it encounters its matching antigen
-engulfs the antigen and digests it
-displays antigen fragments bound to its unique MHC molecules
-combination of antigen and MHC attracts the help of a mature matching T cell
-cytokines secreted by the T cell help the B cell to multiply and mature into antibody producing plasma cells
-released into the blood and then cleared by complement cascade or by the liver and spleen
the pattern of the antigen recognized is the
epitope
antigens that promote an immune response are
immunogens
antibodies have
a constant (Fc) and a variable (Fv or Fab) regions or fragments
link antigen recognition (Fab) with specific effector functions (Fc)
