A state of delayed hypersensitivity was induced in guinea pigs by sensitization with ovalbuminanti-ovalbumin precipitates prepared in the antibody excess zone and injected with complete Freund adjuvant. Skin tests with ovalbumin gave clear-cut delayed type reactions 6 days after sensitization. No circulating antibodies against ovalbumin could be detected. Lymph node cell-suspensions of these animals were prepared at once after the 48-hr skin inspection. 200 × 106 cells of sensitized and nonsensitized animals were incubated with 80, 120, 240 and 300 mg/100 ml of ovalbumin solution, 120 mg/100 ml of human γ-globulin solution, and saline. After this incubation the cells were brought into reaction with an anti-ovalbumin reagent or an anti-human γ-globulin reagent of known titer. After a limited reaction time the cells were sedimented by centrifugation and the antibody titer was determined again in the supernatant reagent.
In all experiments in which a) ovalbumin was brought into reaction with lymph node cells of guinea pigs in the state of delayed hypersensitivity against ovalbumin, and b) these cells were brought into reaction with the antiovalbumin reagent, the titer of this reagent decreased specifically and significantly compared with controls. These results indicate that lymph node cells of sensitized animals possessed an “anti-determination” against the corresponding antigen and the property of fixing this antigen. The site of fixation is thought to be on or near the surface of the cells, and its configuration to be complementary to determinants of the antigen. The immunologic significance of the results and the applicability of the technique are discussed.