Cross-reactions of sera from Toxocara canis-infected mice with Toxascaris leonina and Ascaris suum antigens.

The ELISA method using larval excretory-secretory (E/S) products and homogenized Toxocara canis, Toxascaris leonina and Ascaris suum adult worm extract were used to determine possible cross-reactions in BALB/c and C57BL/10 mice, inoculated with embryonated eggs or adult worm extract of T. canis in single and multiple doses. When we used sera of mice infected with embryonated eggs of T. canis against different heterologous antigens, we observed no cross-reactions in BALB/c mice against A. suum E/S and adult worm extract antigens with a single dose. In multiple doses this was absent too against T. leonina adult worm extract in BALB/c mice, and in both strains against A. suum E/S and adult worm extract. In BALB/c mice inoculated with adult worm extract of T. canis we did not observe cross-reactions with A. suum E/S antigen with both inoculation doses. In the remainder of the experiments, we observed cross-reactions of different intensities.