Identification of a rabbit class I-like thymocyte-specific antigen

The availability of a monoclonal antibody, 5E2, has made it possible to characterize a new class I-like thymocyte-specific antigen in the rabbit. Flow cytometry and cyto-fluorescent microscopy show that approximately 70 to 80% of the cells reacting with 5E2 are located throughout the thymic cortex. Structural studies reveal that the cell surface molecule recognized by 5E2 is a non-covalently associated heterodimer consisting of a 45,000 dalton glycoprotein and a low m.w. β-2-microglobulin protein. Certain properties of the 5E2 antigen were similar to the murine TL and human T6 antigens. Therefore we have tentatively assigned to the 5E2 antigen the designation R-Ta on the premise that the structural gene(s) encoding this molecule will be associated with the rabbit major histocompatibility complex.