T90/44 (9.3 antigen). A cell surface molecule with a function in human T cell activation.

Area of Science:

• Immunology
• Cell Biology
• T cell activation pathways

Background:

• T90/44 is a cell surface antigen found on human T cell subsets.
• It exists as disulfide-bonded dimers and free subunits.
• The 9.3 monoclonal antibody (mAb) specifically binds to T90/44.

Purpose of the Study:

• To investigate the functional role of the T90/44 antigen in T cell responses.
• To determine the effects of 9.3 mAb on T cell activation and function.

Main Methods:

• T cell function assays were performed using T cell clones and peripheral blood lymphocytes (PBL).
• The impact of 9.3 mAb on T cell activation, proliferation, and cytolytic function was assessed.
• Flow cytometry was used to measure T90/44 expression levels.

Main Results:

• 9.3 mAb inhibited the activation of class II-restricted T helper cells reactive to M. leprae antigens.
• 9.3 mAb enhanced the proliferative responses of PBL to PPD and tetanus toxoid.
• High concentrations of 9.3 mAb demonstrated direct mitogenic activity on resting lymphocytes.

Conclusions:

• T90/44 plays a role in antigen-independent T cell activation pathways.
• The 9.3 mAb can modulate T cell activation, with differential effects on T helper and cytotoxic cells.
• Further research into T90/44 as a target for modulating T cell responses is warranted.