Monoclonal antibody KOLT-2 enhances DNA synthesis and expression of IL-2 receptors on activated T cells.

The functional properties of the KOLT-2 antigen, which was placed among the CD28 group in the 3rd International Workshop on Human Leukocyte Differentiation Antigens, are described. The method of production and a detailed characterization of the monoclonal antibody KOLT-2 including stain affinities and influence of T cell activation are presented. While KOLT-2 antigen was selectively expressed on human thymocytes, adult T-cell leukemia-lymphoma cells and activated T cells, the antigen was also spontaneously expressed by resting T cells after 24 hrs culture. Expression was transient, since it disappeared after 96 hrs. DNA synthesis and expression of Tac antigen on activated T cells was enhanced by stimulation with the KOLT-2. These observations suggest that the KOLT-2 antigen may have an important role in the early stages of T cell activation.