Studies based on the mixed antiglobulin reaction have shown that γ-globulin is adsorbed from normal human sera by the cuticle of parasitic nematodes. Using antiglobulins specific for IgA, IgM and IgG, it was possible to demonstrate uptake to titres of 4, 64 and 128, respectively. Adsorption continued for at least 24 h, and the responsible immunoglobulins could be absorbed from the sera by nematode preparations.
A comparison of normal human sera with sera from cases of ascariasis and visceral larva migrans revealed that there was no significant difference between the titre of anti-cuticular immunoglobulins in normal sera or sera from helmin-thiases. It is suggested that these immunoglobulins adsorbed by the nematode cuticle represent cross-reacting, naturally occurring antibodies.
I am sincerely grateful to Professor R. R. A. Coombs, F.R.S., for his help, advice and encouragement, and to Mr M. J. Eburne for splendid technical assistance.