Major histocompatibility Flashcards Preview

HD exam one > Major histocompatibility > Flashcards

Flashcards in Major histocompatibility Deck (16):
1

Human leukocyte antigens

Tightly linked cluster of cell surface glycoproteins that regulate immune cell interactions

2

How many loci of HLA are there?

Three

3

Class I loci

HLA-A, B, and C that are present on nearly all cells and present to CD8+ cells

4

Class II loci

HLA-D (DR, DQ, DP); found on dendritic cells, macrophages, monocytes, and B cells and present to CD4+ cells

5

Class III loci

They happen to be in the area but don't present to T cells

6

What do each of the HLA in class I code for?

A polypeptide of about 44,000 daltons

7

When these cells are on the membrane, with what other component do they associate?

Associate non-covalently with beta-2 microglobulin that is coded by a separate gene

8

Extracellular domains on the alpha chain

Three different domains; alpha-1, 2 and 3. Alpha-3 interacts with the beta-2 microglobulin

9

What percentage of the alpha chain is carbohydrate?

10%

10

Compare the length of amino acids bound by each of the classes of MHC.

Class I: 8-10
Class II: 13-17

11

How large are the alpha and beta chains in MHC class II?

Alpha: 34,000 daltons
Beta: 29,000 daltons

12

Anchor residues for MHC

Related amino acids (that don't need to be the same) which help bind to the receptor

13

Codominance of MHC expression

Everyone displays an equal number of MHC I and MHC II complexes; 3 maternal and 3 paternal class I, as well as 3 maternal/ 3 paternal class II

14

What do the amino acid sequence differences allow?

Peptide binding and T cell recognition

15

MHC restriction

The dependence of T cell reactivity on not only the antigen alone, but on the presence of the antigen in the context of the MHC

16

How are cytotoxic T cells elicited?

By host cells with self MHC that are expressing non-self antigen (cell infected by bacteria, virus)