Characterization of the Granulomatous Inflammatory Response in Experimental Filariasis.
Human lymphatic filariasis affects over 90 million people in the world. A rodent model used to study lymphatic filariasis is the mongolian jird, Meriones unguiculatus, infected with the filarid nematode, Brugia pahangi. A granulomatous inflammatory response occurs in the jird in response to infection with the parasite. Comparisons of the granulomatous inflammatory responses were made in jirds with lymphatic or peritoneal infections. The inflammatory responses were characterized using light microscopy, histochemistry and electron microscopy. The kinetics of the host response to Brugia pahangi in the peritoneal cavity was also determined. Based on these studies, the reactions in the lymphatics and peritoneal cavity appear to be similar. The effect of host genetic background on lymphatic lesion development was also studied using a mutant black strain of the jird. The numbers of developing adult worms within the lymphatic vessels was similar between the two strains of jirds, although black jirds had a significantly higher number of circulating microfilariae than agouti jirds. Results of these studies indicate that different genetic backgrounds do affect the host's cellular and humoral immune responses, however, development of lymphatic pathology is similar. Fibroblast proliferation factors were produced from cells obtained from jirds with either lymphatic or peritoneal infections. In addition, soluble female worm excretory/secretory products stimulate jird fibroblast proliferation, but do not cause proliferation of a mouse embryonic fibroblast cell line (NIH/3T3).