青岛大学基础医学院医学免疫学 chapter8

（一） class I HLA
molecules
1.structure All class I HLA molecules
consist of two noncovalently linked polypeptide chains:
an MHC-encoded polymorphic
polypeptide called chain （or
heavy chain）, containing 3 extracellular domains, called 1, 2, and 3; a short hydrophobic segment ; and the carboxyl terminal residues.
a non-MHC-encoded nonpolymorphic polypeptide called 2-microglobulin（2m） , interacts noncovalently with the extra-cellular portion of the chain and no direct attachment to the cell.
一. Classical class I and II MHC genes
H-2 complex
mouse MHC is localized on the seventeenth chromosome, composed of 4 genetic regions (K, I, S, and D regions). I region can be divided
The interactions of 2m with 1, 2 and 3 domain appear critical for maintaining class I molecules in their native conformation.
peptide-binding region:
into A,A, E,E, etc. subregions.
every genetic region or subregion contains at least one locus. Classical class I MHC loci: K, D, L Classical class II MHC loci: A,A, E,E Classical class III MHC loci: C4, Bf, C2
MHC: A cluster of closely linked genes in one
chromosome, encoding polymorphic cell-surface molecules, which are associated with regulation of immune response, antigen presenting and transplantation rejection.
Section 1 Structure of MHC and
polygene
Structure of MHC is so complicated, its diversity is composed of polygene and polymorphism
Polygene refers to that MHC is composed by multiple neighboring genetic loci, encodes produces to have the same or similar function.
Chapter 8
Major histocompatibility complex（MHC）and coding
molecules
一. Conception of MHC
1．histocompatibility: It is a phenomenon of non-
histocompatibility between donor and recipient. 2．histocompatibility antigen:
represents the alloantigen of individual specificity. It also termed transplantation antigen.
3．major histocompatibility antigen system, MHS:
Antigens of causing vigorous rejection. 4．major histocompatibility complex,
HLA complex
HLA complex located on chromosome 6p21.31， 224 genetic loci, 128 functional genes, 96 pseudogenes
Classical class I MHC loci: A, B, C Classical class II MHC loci: DR, DP, DQ Classical class III MHC loci: C2, C4A, C4B, Bf
Classification of MHC: According to structure and function, MHC are
divided into (1) classical class I and II MHC genes (2) genes associated with immune function
二. H来自百度文库A molecules
class I HLA and class II HLA molecules can be divided into four separate regions: peptide-binding region immunoglobulin-like region transmembrane region cytoplasmic region