The effect of serum and colostrum immunoglobulins from buffaloes infected with Toxocara vitulorum on T. vitulorum larvae in vitro and in vivo in mice.

Serum and colostrum were collected from adult buffalo cows naturally infected with Toxocara vitulorum. When injected into mice, the colostrum reduced the number of larvae of T. vitulorum that migrated in the mice. Injection of particularly the IgG-containing fraction but also the IgM-containing fraction of Sephadex G200-chromatographed colostrum also passively protected mice. When incubated for 6 h in buffalo serum or colostrum or fractions of these from Sephadex G200 and diethylaminoethanol Sephadex, T. vitulorum larvae had their activity in vitro curtailed. When the larvae were then fed to mice, their ability to migrate was markedly inhibited as compared with that of larvae that had been incubated in fetal calf serum or in helminth-free sheep colostrum. Fractions of serum and colostrum containing IgG1 had greater inhibitory effects both on the larvae in vitro and on their subsequent migration in mice than did IgG2-containing fractions. IgM also inhibited the larvae as 2-mercaptoethanol reduction of IgM in the IgM-containing peak eluted from Sephadex G200 reduced the inhibitory activity of this peak, although the activity was not completely abrogated.