In Vivo Treatment of Rats with Monoclonal Anti‐T‐Cell Antibodies: Immunohistochemical and Functional Analysis in Normal Rats and in Experimental Allergic Neuritis

The effects of intraperitoneal injection of monoclonal anti‐rat T‐lymphocyte antibodies were evaluated immunohistochemically and functionally in normal rats and in rats with experimental allergic neuritis. In the normal animals a single injection of OX8 antibodies, reactive with suppressor/cytotoxic T cells, completely eliminated OX8‐reactive cells from peripheral lymphoid organs and from circulation, whereas the ‘pan’ T‐cell‐reactive W3/13 antibodies and the helper T‐cell‐reactive W3/25 antibodies only caused a partial elimination of their respective target cells. Injection of the W3/13 and W3/25 antibodies but not of OX8 antibodies led to a diminished responsiveness to allogeneic stimulation in vitro for spleen cells obtained from the treated rats, whereas the OX8 injection caused a complete elimination of the in vitro cytotoxic response to allogeneic cells in the mixed lymphocyte reaction‐activated spleen cell population. When Lewis rats were injected with peripheral nerve myelin and Freund's adjuvant for the induction of EAN, treatment with W3/13 antibodies completely prevented the onset of disease, whereas treatment with the OX8 antibodies exaggerated the disease symptoms.