Antibody Induced Lysis of PPD-coated Chicken Erythrocytes by Spleen Cells of Non-Immunized Guinea Pigs

Abstract

Chicken erythrocytes coated with PPD were labelled with 51Cr. When incubated with spleen cells from non-immunized animals in the presence of heat inactivated serum from immunized guinea pigs, the red cells were lysed as assessed by isotope release. The reaction was highly specific and required direct contact between target cells and spleen cells. Cytotoxicity of normal spleen cells was observed after preincubation of the PPD-coated erythrocytes, or when immune serum was present in the incubation mixture. Spleen cells pretreated with immune serum exhibited an activity of low degree. Sera from animals injected with tubercle bacilli or with PPD in incomplete Freund’s adjuvant were active, whereas sera from animals immunized with alum precipitated PPD were of weak or doubtful activity. The stimulating activity of sera increased with the intensity of immunization. Cytotoxicity inducing activity and haemagglutinating antibody titers were roughly correlated in animals injected with PPD but not in animals immunized with tubercle bacilli.