Regulation of the immune response to polyvinylpyrrolidone: Effect of antilymphocyte serum on the response of normal and nude mice

The plaque-forming cell (PFC) responses of normal and congenitally thymus-deficient (nude) mice to polyvinylpyrrolidone (PVP) were compared. Normal and nude mice responded similarly to an optimally immunogenic dose of PVP. Antithymocyte serum or antilymphocyte serum treatment of immunized mice caused a five to 10-fold increase in the PVP-specific PFC response in normal mice; the response in nude mice was not increased by such treatment. The data suggest that, although thymus-derived cells are not an absolute requirement in the immune response to PVP, these cells can regulate the magnitude of the immune response to this antigen.