The CD3 antibody recognizes 22/26/30 kD MW lymphocyte surface molecules associated with the T cell antigen receptor complex. Reacts with 85% of peripheral blood T lymphocytes, 70% of thymocytes, the majority of T cell chronic lymphocytic leukaemias, Sezary leukaemias and approximately 70% of acute lymphoblastic leukaemias of T cell origin.
The CD8 antibody recognizes 30/32 kD MW lymphocyte surface antigen identified by monoclonal antibodies belonging to the CD8 cluster on a sub-population of peripheral blood T lymphocytes, 60% of thymocytes, and a limited number of malignancies of T cell origin. Normal B lymphocytes, monocytes or granulocytes do not express surface CD8 antigen.
The CD45 antibody recognizes 180, 195, 205, 220, kD MW components of the leucocyte common antigen complex to be found on lymphocytes, monocytes, granulocytes, thymocytes and malignant T and B cells. No reactivity has been observed with primary or metastatic carcinoma cells. Plasma cells or myeloma cells may have weak expression or be negative for this antigen.
Finally, CD4 antibody recognizes 60Kd MW lymphocyte surface antigen identified by monoclonal antibodies belonging to the CD4 cluster and present on 54% of peripheral blood T lymphocytes, 50% of thymocytes and some malignant cells of T cell origin. Normal B lymphocytes, monocytes or granulocytes do not express surface CD4 antigen although cytoplasmic expression has been observed in monocytes/macrophages. The CD4 positive T lymphocyte subpopulation has been characterised functionally as comprising helper cells active in amplification of immune responses.