IMPACT OF MICROFILAREMIA ON MAINTENANCE OF A HYPORESPONSIVE CELLULAR IMMUNE-RESPONSE IN BRUGIA-INFECTED GERBILS (MERIONES-UNGUICULATUS)

The purpose of these experiments was to define the significance of the microfilarial stage to the hyporesponsive condition seen in lymphatic filariasis. Two types of experiments were conducted with Brugia pahan gi-infected gerbils. In one, in vitro lymphocyte blastogenesis and in vivo granuloma formation in response to parasite antigen were correlat ed to microfilaremia in chronically infected individuals. In a second set of experiments, the level of in vivo granuloma formation was asses sed following chemotherapeutic removal of microfilariae with ivermecti n. The results indicated that the microfilarial stage alone is not res ponsible for the maintenance of the low cellular responses seen during chronic infections in this model. Furthermore, the data suggest that the degree of downregulation of these responses may be related to para site burden.