HLA-G polymorphisms: ethnic differences and implications for potential molecule function.
OBJECTIVE
Human leukocyte antigen (HLA)-G is uniquely expressed on extravillous cytotrophoblasts of the placenta and is postulated to be a mediator of maternal immune tolerance. Although it was originally considered to be nonpolymorphic, variations of the HLA-G DNA sequence have been reported, and a limited number of HLA-G alleles been defined.


METHODS
The HLA-G wild-type sequence was compared with HLA-A2 with regard to the conservation of functionally essential parts of classical HLA-I molecules. HLA-G polymorphisms were analyzed under the aspect of ethnic differences, site, and consequences for postulated molecule functions.


RESULTS
HLA-G exhibits a high degree of conservation relative to HLA-A2 in functionally relevant sites of HLA-class I molecules. However, polymorphic sites in HLA-G and classical HLA loci are not congruent.


CONCLUSIONS
The type and localization of HLA-G polymorphisms suggest that different parts of HLA-G molecule underlie different selective constraints.
University of Bonn, Department of Obstetrics and Gynecology, Germany.
K
K
van der Ven
S
S
Skrablin
C
C
Ober
D
D
Krebs
D005006:Ethnicity / Q000235:genetics*; D005260:Female; D006680:HLA Antigens / Q000235:genetics* / Q000502:physiology; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I / Q000235:genetics* / Q000502:physiology; D006801:Humans; D011110:Polymorphism, Genetic; D011247:Pregnancy
D006680:HLA Antigens; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I