Regulation of the Immune Response

Question 1

What is immunological tolerance?

Answer 1

tolerance is the lack of response to a specific antigen

Question 2

Immunological tolerance involves

Answer 2

elimination of cell populations reactive to that antigen, neutralization of reactive cell populations, generation of unique cell populations that can produce antigen specific tolerance

Question 3

mechanisms of tolerance induction

Answer 3

deletion of reactive cells, inactivation of reactive cells (anergy)

Question 4

Clonal Deletion

Answer 4

immature or developing T cells are deleted. programmed cell death or apoptosis. eliminates autoreactive T cells in the thymus. result of tight association of the autoreactive TCR to MHC presented antigen on specialized thymic dendritic cells

Question 5

Clonal Anergy

Answer 5

immature cells, exposed to antigen in association with appropriate MHC can be functionally eliminated, especially if these cells do not receive appropriate co-stimulatory signal.

Question 6

functional deletion

Answer 6

delete antigen specific helper cells and therefore lose CD8+ T cell cytotoxicity or B cell antibody formation that requires help

Question 7

Generation of suppressor or regulatory T cells

Answer 7

active process involving antigen/MHC specific cells

Question 8

Blocking of presentation or activation

Answer 8

directed at co-receptors (CD4 or CD8) or at MHC molecules so as to reduce effective presentation

Question 9

mechanisms of tolerance in T cells

Answer 9

clonal deletion, clonal anergy, functional deletion, generation of suppressor or regulatory T cells, blocking of presentation or activation

Question 10

mechanisms of tolerance in B cells

Answer 10

clonal deletion of B cells, clonal abortion/clonal anergy/functional deletion

Question 11

inducing and maintaining tolerance depends on

Answer 11

maturity of host, immunogenicity of a substance, dose of the substance, form of the substance, immunosuppressive drugs

Question 12

Tregs

Answer 12

CD4+ T cells that can control autoreactive CD4+ T cells through the release of cytokines. They must be positively selected in the thymus on peptide loaded MHC class II molecules.

Question 13

Antigen regulation of immune response

Answer 13

amount of antigen, portal of entry of antigen, packaging of antigen, presentation of antigen