MHC

Question 1

Specialized glycoproteins coded for by genes located in a gene cluster

Answer 1

• the Major Histocompatability Complex (MHC)

Question 2

Determine which MHC molecules an individual animal can produce

Answer 2

• MHC genes

Question 3

Determine which antigens can be presented to the cells of the immune system

Answer 3

• MHC molecules

Question 4

MHC restriction

Answer 4

• antigens can only trigger an immune response if they are bound to a self-MHC molecule

Question 5

______ can only recognize antigens in the context of self-MHC molecules

Answer 5

• T-cells

Question 6

What kind of immune response is most helpful to deal with extracellular pathogens?

Answer 6

• humoral immune response

- > antibodies neutralize extracellular pathogens

Question 7

What kind of immune response is most helpful to deal with intracellular pathogens?

Answer 7

• cell mediated immune response

- > kill infected/tumor cells

Question 8

How does an exogenous antigen get into the endogenous pathway?

Answer 8

• cross-presentation (cross-priming)

Question 9

Cross-presentation (cross-priming)

Answer 9

• Exogenous antigens may enter the endogenous antigen pathway in an antigen presenting cell (APC) and thus be presented via MHC-1 to CTLs (cytotoxic T-lymphocytes)
• > phagosomal leak

Question 10

What response is needed in order to kill virally-infected cells?

Answer 10

• a CTL (CMI) response

Question 11

How can an endogenous viral antigen end up in the exogenous pathway?

Answer 11

• in APCs via phagocytosis of ingected cells

Question 12

How is it that in all acquired immune responses to a pathogen, we will see both CMI and humoral immune responses?

Answer 12

• via cross presentation (exogenous on MHC-I) and phagocytosis of infected cells (endogenous on MHC-II)

Question 13

Alleles code for different amino acid sequences for the ______ of the MHC molecule

Answer 13

• peptide binding groove

- > structure of the MHC binding groove determines what antigens it can bind and present

Question 14

What type of specificity do MHC molecules have?

Answer 14

• Broad specificity (promiscuous)

- > a given MHC molecule can present ONE peptide at a time, but can bind several different peptides

Question 15

What type of specificity do TCR (T-cell receptors) molecules have?

Answer 15

• Unique specificity

- > can only interact with self MHC presenting one specific peptide

Question 16

MHC genes determine disease susceptibility when the _____ immune responses are essential

Answer 16

• acquired

Question 17

In humans almost all autoimmune diseases are linked to certain ______

Answer 17

• MHC alleles (genes)

Question 18

Is it an evolutionary advantage or disadvantage to be heterozygous?

Answer 18

• advantage because more heterozygous MHC = greater diversity of bound peptides
• > if lack of MHC diversity aka homozygous populations, they are less likely to have individuals who can respond to a novel pathogen

Question 19

Do MHC genotypes cause disease?

Answer 19

• NO, they are linked to risk only