Class II determinants recognized by TNP-specific cloned human T cell lines

Area of Science:

• Immunology
• Molecular Biology
• Genetics

Background:

• T cell recognition of modified self-antigens is crucial for immune responses.
• Human T lymphocyte clones (TLC) are valuable tools for studying antigen presentation.
• Trinitrophenyl (TNP) modification serves as a model hapten for investigating immune recognition.

Purpose of the Study:

• To characterize the restriction elements involved in T cell recognition of TNP-modified autologous cells.
• To investigate the role of different Human Leukocyte Antigen (HLA) class II molecules (DR, DP, DQ) in presenting TNP.
• To identify specific determinants on HLA molecules that present TNP to T lymphocytes.

Main Methods:

• Generation of cloned human T lymphocyte lines against TNP-modified autologous cells.
• Analysis of TLC reactivity on HLA-typed antigen-presenting cells.
• Monoclonal antibody (MoAb) inhibition studies to map determinant locations.

Main Results:

• TNP was recognized in the context of various DR and DP associated determinants.
• No TLC were restricted by DQ determinants.
• DR1, DR2, DR4, DR5, DR7, DRw52, and DRw53 functioned as restriction elements.
• Two distinct regions of the DP4 molecule presented TNP, one polymorphic and one nonpolymorphic.
• MoAb blocking suggested these DP determinants are on different parts of the molecule.

Conclusions:

• Both polymorphic and nonpolymorphic restriction determinants on DR and DP molecules present conventional antigens to autologous lymphocytes.
• HLA-DQ molecules do not appear to restrict TNP recognition by these TLC.
• This study elucidates the complex role of HLA class II molecules in hapten-specific T cell responses.