Characterization of surface and excretory‐secretory antigens of Toxocara canis infective larvae

Abstract

The surface antigens of T. canis infective larvae were identified by radioiodination and compared with the excitatory-secretory (ES) products released by the larvae in vitro. Common antigens of MW 32,000 and 120,000 are found on the larval surface, in the ES material and in culture supernatant following surface iodination of living T. canis larvae. The 120,000 antigens consist of 3 closely migrating bands in each of these preparations. One prominent ES component, of MW 400,000, is not found on the larval surface. Additional molecules of 55,000 and 70,000 are present in the ES material, but while these may be discerned in surface preparations there appears to be more heterogeneity of surface molecules in this size range. Both sets of molecules are antigenic to infected patients and experimental animals. A comparison of characterized human sera show that a radioimmunoprecipitation assay correlates with the established ELISA [enzyme linked immunosorbent assay] test (r = 0.89), and that all labeled molecules are antigenic to the infected host.