U. S. Department of Health, Education and Welfare, Public Health Service, National Institutes of Health, National Institute of Allergy and Infectious Diseases, Laboratory of Parasitic Diseases, Bethesda, Maryland 20014
Toxoplasma hemagglutination antigen was fractionated on a hydroxyapatite column and by differential centrifugation. Antisera to individual fractions were prepared in rabbits and tested by both HA and dye tests. Sera from rabbits inoculated with fractions eluted from the hydroxyapatite column with low molarity phosphate reacted in the HA test, but not in the dye test. Sera from rabbits inoculated with fractions eluted with 0.15 M buffer or higher reacted in both the HA and dye tests. Predominantly HA antibodies resulted from immunization of a rabbit with the 40,000 rpm supernatant fraction; predominantly dye-test antibodies resulted from immunization of a rabbit with Toxoplasma “ghosts” that were left after cell sap had been extracted by lysing the trophozoite in distilled water.
Present address: Division of Biologics Standards, National Institutes of Health, Bethesda, Maryland 20014.