T-cell clonal analysis of HLA-DR2 haplotypes

Area of Science:

• Immunogenetics
• Molecular immunology
• Histocompatibility

Background:

• Serologically defined Human Leukocyte Antigen (HLA) DR2 haplotypes exhibit T cell-defined subdivisions (HLA-Dw/LD clusters).
• Understanding these subdivisions is crucial for dissecting immune responses and transplantation compatibility.

Purpose of the Study:

• To define Human Leukocyte Antigen (HLA)-DR and -DQ associated Dw/LD polymorphisms within DR2 haplotypes.
• To characterize T cell-mediated recognition of specific determinants on HLA-DR2 molecules.

Main Methods:

• Generation of cytotoxic T cell clones against DR2 haplotypes.
• Monoclonal antibody inhibition studies to categorize T cell clones (DR, DQ, DP, class I-directed).
• Analysis of determinant distribution using cell panels representing various HLA-Dw subtypes.

Main Results:

• DR-directed T cell clones identified determinants specific to certain HLA-Dw subtypes, broadly reactive DR2 determinants, and determinants shared between specific Dw subgroups (e.g., Dw2/Dw12, MN2/FJO/AZH/LD-5a).
• DQ-directed clones predominantly recognized determinants specific to the sensitizing HLA-Dw subtype.
• A subset of T cell clones showed reactivity against multiple DR2 subtypes and other HLA-Dw types, independent of monoclonal antibody blocking.

Conclusions:

• Specific determinants on HLA-DR and -DQ molecules are associated with particular HLA-Dw subgroups within the DR2 haplotype.
• These findings highlight molecular polymorphism within HLA-DR2 that influences allogeneic T cell recognition.
• The study provides insights into the basis of immune response variations related to HLA-Dw/LD polymorphisms.