Immunohistochemical Demonstration Of Ada And Adcp On The Cell-Surface Of Human T-Lymphoid Cells

ADA plays an important role in the development of the immune system and the enzyme is probably associated with T-lymphocyte differentiation. ADA has been shown to exist in different molecular weight forms. In man the major forms are the red cell ADA or ADA-S and the tissue specific ADA or ADA-L. ADA-S can be converted to ADA-L by complexing with ADCP. Intact human peripheral T lymphocytes and human thymocytes were first incubated with rabbit anti-ADA and anti-ADCP antisera, followed by incubation with FITC-labeled swine anti-rabbit IgG. Since only cell surface ADA and ADCP would be exposed to the antisera, fluorescence indicates ADA and ADCP expression on the outer cell membrane.