STUDIES ON CYTOPHILIC ANTIBODIES.

Abstract

Summary Non‐inbred Swiss mice were immunized by intraperitoneal or sub‐cutaneous injections of sheep erythrocytes in saline. Freund's incomplete adjuvant or Freund's complete adjuvant. Titrations were made of macrophage cytophilic antibodies. complement‐fixing (immune adherence) antibodies and direct haemagglutinating antibodies in sera obtained at weekly intervals up to 4 weeks. Early and delayed hypersensitivities were estimated by footpad tests with sheep erythrocytes. When the intraperitoneal route of immunization was used, cytophilic antibodies and delayed‐type hypersensitivity developed consistently only after the erythrocytes had been injected in Freund's complete adjuvant. When the subcutaneous route was used, cytophilic antibodies and delayed‐type hypersensitivity developed after the erythrocytes had been injected in complete or incomplete adjuvant but not after they had been injected in saline. There was a correlation between the intensity of delayed (48 hr.) footpad reactions and the levels of cytophilic antibodies in serum as well as between the intensity of early (4 hr.) reactions and the levels of complement‐fixing antibodies. A second injection of antigen in saline (footpad test) was usually followed by a rise in titre or by the reappearance, or even by the first appearance, of cytophilic antibodies in the serum. Cytophilic antibodies could appear in the absence of detectable complement‐fixing antibodies and vice versa, and there was overall no correlation between the levels of cytophilic and complement‐fixing antibodies in the sera.