Prevention of blood transfusion-induced immunization against transplantation antigens by treatment of the blood with antibody.

The experiments reported show that alloantisera directed against the transplantation antigens of allogeneic blood will completely suppress (1) the lymphocytotoxic antibody response to the blood and (2) its ability to sensitize against renal allografts. AS (Ag-B1) rats injected i.v. with 1 ml of August (Ag-B5) blood gave a strong primary (mainly IgM) and secondary (IgG) lymphocytotoxin response. If the August blood was mixed with AS anti-August serum in vitro before injection, the lymphocytotoxin response was completely suppressed. However, rats given the blood-antiserum mixture gave a primary IgM response upon rechallenge with blood. Rats previously primed with blood had substantial but only partial suppression of the secondary response if the secondary stimulus was given as a blood-antiserum mixture. An AS anti-Wistar (Ag-B2) serum, which showed only weak serological cross-reaction with August lymphocytes, could suppress the lymphocytotoxin response to August blood. A protocol of widely spaced injections of August blood was found to sensitize AS rats to (AS X August)F1 renal allografts. If the blood injections were given as a blood-antiserum mixture, sensitization was prevented. In addition, the blood-antiserum mixtures were found to induce a slight degree of immunosuppression. The clinical application of this approach to preventing blood transfusion-induced sensitization is discussed.