Major Histocompatibility Complex...presence of multiple alleles in the population for a given locus. •The sequence variation between alleles is clustered to the α1/α2 and α1/β1

Major Histocompatibility Complex Chapter 8

I

TLA

Qa-1 Qa- 2

TL

TLA

Figure 8-1

MHC

• Haplotype: – The set of alleles present on each

chromosome – Outbred individuals have 2 haplotypes – Inbred individuals have 2 identical

haplotypes

• MHC molecules are co-dominantly expressed.

Inbred Mice

• In a given inbred strain of mice, every mouse is genetically identical to every other mouse in that strain. – Syngenic – Allogenic

• Strains or individuals express different alleles.

Graft Nomenclature • Isograft

– Graft from one individual to itself

• Syngenic – Graft between identical individuals

• Allograft – Graft between individuals of different strain.

• Xenograft – Graft between different species

Diversity • MHC molecules exhibit a high degree of

diversity • Diversity is due to polymorphism or the

presence of multiple alleles in the population for a given locus.

• The sequence variation between alleles is clustered to the α1/α2 and α1/β1 regions of class I and class II molecules respectively.

Ting and Trowsdale, 2002