T cell-activating protein on murine lymphocytes.

Area of Science:

• Immunology
• Molecular Biology
• Cell Biology

Background:

• A functional T cell surface molecule, T cell-activating protein (TAP), has been identified on murine lymphocytes.
• TAP is a protein with an apparent molecular mass of 10-12 kilodaltons (kDa) nonreduced, 16-17 kDa reduced.

Purpose of the Study:

• To characterize the function and expression of T cell-activating protein (TAP) on murine lymphocytes.
• To investigate the role of TAP in T cell activation, proliferation, and immune cell maturation.

Main Methods:

• Identification and characterization of TAP on murine lymphocytes.
• Analysis of TAP expression patterns in different T cell subsets and thymocytes.
• Investigation of TAP's role in T cell activation and lymphokine production via antibody cross-linking.
• Mapping of the gene controlling TAP expression and comparison with hematopoietic antigen loci.

Main Results:

• Cross-linking of TAP induces profound T cell activation, lymphokine production, and cell cycle entry.
• Antibody binding to TAP modulates antigen-driven T cell stimulation, indicating functional distinctness from the T cell receptor complex.
• TAP expression is found on distinct T cell subsets and thymocytes, with altered profiles upon activation.
• The gene for TAP is mapped and linked to the Ly-6 locus, but TAP is molecularly distinct from these antigens.

Conclusions:

• TAP is a functional T cell surface molecule involved in T cell activation and proliferation.
• TAP expression patterns suggest a role in defining the immunocompetent compartment of the thymus and potentially in functional T cell maturation.
• TAP represents a novel target for modulating T cell responses and understanding immune cell development.