Homocytotropic Antibody Response to the Nematode Nippostrongylus brasiliensis in the Rat: Studies on the Worm Antigen

Abstract

A worm antigen which reacted with rat homocytotropic antibody to Nippostrongylus brasiliensis was demonstrated in culture fluids of adult worms. Production of antigen by adult worms in-vitro declined during the 1st 4 days of maintenance in serum-free medium but was more prolonged in serum-supplemented medium. Six antigens were demonstrated in worm extract using rabbit antisera of restricted immunological specificity. Four of these antigens were present also in culture fluids of adult worms. On preparative agar electrophoresis of worm extract, the antigen which combined with rat homocytotropic antibody to N. brasiliensis migrated towards the cathode with a mobility resembling that of rat [gamma] A-globulin. Limited evidence from physicochemical studies suggested that the antigen is a conjugated protein with a molecular weight between 12,000 and 15,000.