Five antigens on human T cells detected by mouse monoclonal antibodies.

Five antigen systems were defined by the monoclonal antibodies (MoAb) produced against mature T cells. The antigens recognized were grouped into two categories based on the antigen distribution on T cells. (a) Tp 120 [mol. wt 120 kilodaltons (120kD)] and Tp40 (40kD), these are on most peripheral T cells, but not on any other cell lineages, i.e. pan-T antigen. (b) Ts32 (32kD), Ts145 (145kD) and TsA (not determined), these antigens are present only on certain populations of peripheral T cells, i.e., T subset antigen. Among these five, Ts145 and TsA are probably novel T cell antigens. Cell surface phenotypes of leukaemias and lymphomas were typed with these MoAb. Ia like antigen negative, null cell type acute lymphocytic leukaemia (Ia- null ALL) are Tp40+, suggesting that this type of ALL belongs to a T cell lineage. T cell ALL (T-ALL) and lymphoblastic lymphoma (LL) were both Tp40+, Ts32+, TsA+ and a half of the cases were Tp120+, but the expression of Tp40 was stronger on LL cells. Mature T cell (T2) lymphoma and adult T cell leukaemia (ATL) were Tp120+, TsA+, while Tp40 was weakly expressed on only one third of the cases. These MoAb were found to be useful to estimate the origin of various T cell malignancies.