The Adaptive Immune System Flashcards
Humoral immunity
this is centered on antibody production by plasma cells, which are activated B-cells
antibodies
these proteins target a particular antigen. they containtwo heavy chains and two light chains. they have a constant region and a variable region; the tip of the variable region is the antigen-binding region
what happens when humoral immunity is activated?
the antigen-binding region undergoes hypermutation to improve the soecificity of the antibody produced. Cells may be given signals to switch isotypes of antibody (IgM, IgD, IgG, IgE, IgA)
what can circulating antibodies cause?
- opsonize antogens: mark them for destruction
- cause agglutination into insoluble complexes that are ingested by phagocytes, or neutralize pathogens
what do memory B-cells do?
they wait for a second exposure to a pathogen and can then mount a more rapid and vigorous immune response (secondary response)
Cell-mediated immunity
aka cytotoxic immunity: is centered on the functions of T-cells
about T-cells
T-cell undergo maturation in the thymus through positive selection (only selecting for T-cells that can react to antigen presented on MHC) and negative selection (causing apoptosis in self-reactive T-cells).
-the peptide hormone thymosin promotes T-cell development
about helper T-cells
aka: CD4+
they respond to antigen on MHC-II and coordinate the rest of the immune system, secreting lymphokines to activate various arms of immune defense.
- Th1 cells secrete interferon gamma, which activates macrophages
- Th2 cells activate B-cells
Cytotoxic T-cells
aka: CD8+
these respond to antigen on MHC-I and kill virally infected cell
Suppressor (regulatory) T-cells
these tone down the immune response after an infection and promote self-tolerance
memory T-cells
serve a similar function to memory B-cells
in autoimmune conditions..
a self-antigen is recognized as foreign, and the immune system attacks normal cells
in allergic reactions
nonthreatening exposures incite an inflammatory response
immunization
this is a method of inducing active immunity (activation of B-cells that produce antibodies to an antigen) prior to exposure to a particular pathogen.
passive immunity
this is the transfer of antibodies to an individual
