Two monoclonal antibodies recognizing subpopulations of canine T lymphocytes with or without suppressor/cytotoxic functions.

Two monoclonal antibodies (mAb) were studied in regards to their ability to differentiate functionally distinct subsets of canine lymphocytes. MAb DT-2 (IgG2a) reacts with 33-55% of canine peripheral blood mononuclear cells (PBMC), which are also surface immunoglobulin (SIg) negative. Cytolytic treatment with DT-2 eliminates the ability of PBMC to respond to allogeneic cells and mitogens but does not affect alloantigen-primed cytotoxic or suppressor cells. MAb E11 (IgG3) reacts with 15-40% of PBMC which are also SIg negative. Cytolytic treatment with E11 affects responses of PBMC to allogeneic cells or mitogens to a lesser extent than DT-2 but eliminates cytotoxic and suppressor cells among alloantigen-primed lymphocytes. Thus, canine helper cells appear to be Thy 1+, 7.2+, DT-2+, DLy 6+, DLy 1+, E11-, SIg-, and cytotoxic/suppressor cells Thy 1+, 7.2+, E11+, DT-2+, DLy 6-, DLy 1-, SIg-.