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TAP2 gene polymorphism segregates with DR-DQ in DR/DP recombinant siblings
T H Eiermann1, J Fakler, S F Goldmann
1Department of Transfusion Medicine, University of Ulm, Germany.
Human Immunology
|November 1, 1993
Summary
Transport-associated gene (TAP2) polymorphism does not explain minor histocompatibility differences in HLA-identical siblings. TAP2 gene variants are unlikely to cause differing peptide loading in these closely matched individuals.
Area of Science:
- Immunogenetics
- Molecular Biology
- Human Genetics
Background:
- The transport-associated gene (TAP2) plays a role in antigen presentation.
- Polymorphism in TAP genes can influence peptide loading onto MHC class I molecules.
- Previous studies suggested TAP2 variations might affect antigen presentation in humans.
Purpose of the Study:
- To investigate whether TAP2 gene polymorphism is relevant to peptide loading in humans.
- To determine if TAP2 variations contribute to minor histocompatibility differences in HLA-identical siblings.
Main Methods:
- Typing of TAP2A and TAP2B alleles in 41 HLA-ABC, DR-identical sibling pairs using PCR-SSO hybridization and direct genomic sequencing.
- Inclusion of recombinant siblings differing in GLO or DP types.
- Analysis of TAP2 gene segregation with DR-DQ types.
Main Results:
- TAP2 allele frequencies were consistent with previous reports (74% TAP2A, 26% TAP2B).
- TAP2 gene polymorphism segregated with the DR-DQ type, indicating its location telomeric to the DR-DP recombination hot spot.
- TAP2 gene differences were found to be very unlikely in HLA-identical siblings.
Conclusions:
- TAP2 gene polymorphism does not account for minor histocompatibility antigenic differences in HLA-identical siblings.
- Variant peptide loading due to TAP2 polymorphism is not a likely cause of these differences in closely matched individuals.