Chicken-Activated-T-Lymphocyte-Antigen (CATLA) recognized by monoclonal antibody INN-CH 16 represents the IL-2 receptor

Abstract Monoclonal antibody INN-CH 16 recognizes a surface determinant exclusively present on activated chicken T lymphocytes. The present experiments suggest that this chicken activated T lymphocyte antigen (CATLA) represents the chicken IL-2 receptor or an associated structure, as (i) the kinetics of CATLA expression during T cell activation are analogous to those described for the mammalian receptor for IL-2, (ii) the IL-2 dependent proliferation of mitogen prestimulated chicken lymphocytes is competitively inhibited by INN-CH 16, and (iii) pretreatment of T lymphoblasts with INN-CH 16 drastically reduces their capacity to absorb IL-2 activity from supernatants of mitogen activated chicken lymphocytes.