Histocompatibility Cht Exam

Front 1

What is the HLA gene complex?

Back 1

short arm of chromosome 6
4,100 kbp
200 loci

Front 2

What is the Class I region of the HLA gene?

Back 2

Encodes for heavy chains of HLA-A,B,C

Front 3

What is the Class II region of the HLA gene?

Back 3

Encodes genes for alph and beta chains for HLA-DR,DQ,DP

Front 4

What are 3 levels of variation among different population?

Back 4

1. HLA alleles occur in all population, but at different frequencies
2. HLA alleles restricted to a specific population
3. Haplotypes held together through linkage disequilibrium appear to be population restricted

Front 5

HLA molecules

Back 5

Expressed on cell membranes of many different cell types.
Constructed of more than 300 amino acids

Front 6

What is the distribution of Class I molecules?

Back 6

Found on many, but not all nucleated cells. Also occur on platelets.

Front 7

Expression of Class II molecules

Back 7

Restricted to few cells-B cells, dendritic cells, Langherhans cells within the skin, and on some endothelial cells.

Front 8

Cytokines (Interferon)

Back 8

Initiate increased or new expression of HLA molecules

Front 9

Physical structure of HLA Class I molecule

Back 9

Contain alpha (heavy) protein chain (alpha1,2,3 domains) that is noncovalently associated with B-2 microglobulin (light) non-polymorphic protein

Front 10

Physical structure of HLA Class II molecule

Back 10

two distinct glycoprotein chains, alpha and beta

Front 11

What is an epitope or antigenic determinant?

Back 11

the minimum structural unit that can be recognized by a B or T cell receptor

Front 12

What is an alloepitope?

Back 12

epitopes that differ among individual members of the same species

Front 13

Peptide Groove

Back 13

Where serologically definble epitopes are located.

Front 14

Nonsynonymous Substitution

Back 14

substitutions of an amino acid with different biochemical characteristics (alanine-->glutamine)
are more frequent in the region of peptide groove

Front 15

Private Epitope

Back 15

epitopes that occur on a single gene product such as HLA-A2

Front 16

Public Epitopes

Back 16

HLA antibodies that react with more than one gene product and detect crossreactive epitope
example Bw4 and Bw6

Front 17

Haplotype

Back 17

half of a genotype
combination of linked HLA genes transmitted on a single parental chromosome

Front 18

Recombinant HLA haplotypes

Back 18

created during meiotic cell division of germ cells
chromosomal replication-->X shaped chiasmata-->cross over site-->complemetnary exchange of genetic material

Front 19

Frequency of recombination

Back 19

directly related to distance between loci