Activation of complement, the induction of antibodies to the surface of nematodes and the effect of these factors and cells on worm survivalin vitro

摘要

AbstractThis report describes the effect on various stages in the life cycle of the nematodesT. spiralisandN. brasiliensisof complement, antibodies from rats infected with these parasites and several different cell types. The cuticle of the infective larvae and adult worms of both nematode species activates complement via the alternative pathway, but the cuticle of newbornT. spiralislacks this property initially. As newborn larvae grow, however, the newly formed cuticle in the midregion of their body is able to activate complement. Rats infected with either nematode species produce antibodies to the cuticle of all life cycle stages which show marked specificity to each stage in the life cycle. Whereas the cuticle ofT. spiralisreacts evenly over the entire surface both to complement and to antibodies, the reaction of the cuticle ofN. brasiliensisto either reagent is patchy. Infective larvae ofN. brasiliensiswere killedin vitroin the presence of complement, by neutral red‐positive peritoneal macrophages which were nonadherent to plastic. The infective and newborn larvae ofT. spiraliswere killed by eosinophil‐enriched cell populations and antibodies. The speed of eosinophil killing of theT. spiralislarvae was enhanced when the serum was freshly collected and when the eosinophil suspension also contained neutral red‐positive nonadherent macrophages. Newborn larvae ofT. spiralisand infective larvae ofN. brasiliensisassumed a rigid appearance at death. Infective larvae ofT. spiralisburst, extruding their internal organs through their cuticle weakened by antibodies and the