Exam II - Regulation of Immune Flashcards
Explain self limitation
Each immune response eliminates the antigen that initiated the response, which eliminates the necessary 1st signal for lymphocyte activation
Explain why Ag is the “engine that drives the immune response”
Because when the immune system encounters the antigen, it drives either immunity or tolerance
What Ag concentrations induce tolerance?
very large doses of antigen
What types of immunity are triggered by protein Ag?
humoral and cell-mediated responses
What types of immunity are triggred by non-protein Ag?
immune response to T-independent antigens consisting largely of IgM antibodies
What is the effect of the presence of competing Ag?
regulates the immune response of an unrelated antigen
Which portals of entry are more likely to induce tolerance?
IV and oral
How does Ab exert feedback inhibition on its own production?
Antibodies eliminate the antigen, which thereby removes the initiating stimulus for antigen-reactive B cell clonal expansion
How do circulating Ag-Ab complexes suppress specific immune responses?
By simultaneously binding to BCR and CD32.
Explain the role of antiapoptotic proteins in the immune response.
Their role is to allow the lymphocytes to survive, though the only cells surviving are the long-lived, functionally quiescent memory cells
What does the CTLA-4 receptor bind to?
It binds to B7-1 and B7-2
Which cells express CTLA-4?
It is expressed by activated T cells
What is the function of binding CTLA-4 to B7-1 and B7-2?
It sends inhibitory signal to the T cell
Which cells are regulatory T cells?
THey are CD8+, distinct from helper and cytotoxic T cells that inhibit immune responses by secreting antigen specific “surpression factors”
Which cytokines inhibit IFN-γ & macrophage activation?
IL-10, IL-4, and IL-13
