Antibodies of Toxoplasma gondii

Abstract

1. That the number of toxoplasma organisms in the dye test affects the titre of the test serum is confirmed. 2. Evidence is presented that the toxoplasma cytoplasm-modifying substance present in the peritoneal exudate of mice injected with large numbers of toxoplasma organisms more than 3 days previously is probably antibody. 3. Various chemicals including detergents were capable, in high concentration, of producing a false positive dye test. 4. Evidence is presented that there are two complement-fixing antigens, one with a low sensitivity and a low density, the other with a high density and a sensitivity close to that of the dye test. Heating the heavy antigen to 56° C. for 1 hr. removes most of its anticomplementary effects without altering its complement-fixing activity. 5. The light antigen mentioned above was capable of producing a precipitation line in agar double-diffusion experiments, but did not inhibit dye-test antibody when mixed with an equal volume of antiserum in the dye test. 6. The heavy antigen inhibited dye test antibody when mixed with an equal volume of antiserum in the dye test.