The in-vitro interaction of eosinophils, neutrophils, macrophages and mast cells with nematode surfaces in the presence of complement or antibodies

Abstract

The adherence in vitro of leucocytes to the surface of various stages in the life cycle of T. spiralis and N. brasiliensis in the presence of serum was examined. Considerable differences were observed in the behaviour of mast cells, eosinophils, neutrophils and macrophages in this interaction. Mast cells adhered for a short time, did not flatten onto the surface and did not degranulate. Adherence ceased after 4-6 hr. Eosinophils adhered within minutes to the surface or worms, flattened and degranulated; only their cytoplasmic remnants could be seen on the worms' surface after 24 hr in culture. In contrast, only a small area of the cytoplasmic membrane of neutrophils flattened on the surface of the worms and adherence ceased after 2-24 hr. The NBT conversion reaction showed a positive deposit at the interface between neutrophils and parasites during neutrophil adherence. This deposit remained as "foot prints" on the surface of the nematodes following neutrophil detachment. This positive NBT reaction occurred only with neutrophils and not with eosinophils, mast cells or macrophages. Macrophages adhered permanently to the surface of these worms, they did not flatten and retained their integrity. Under the light microscope the cytoplasmic inclusions appeared to decrease in size during culture. Electron microscopy revealed the presence of fewer granules and an increased number of vacuoles in later cultures of macrophages. These findings are discussed in relationship to the immunopathology of nematode infection in vivo.