This project deals with both the laboratory and clinical aspects of infection caused by the intestinal nematode, Strongyloides stercoralis. The laboratory research involves analysis and characterization of parasite antigens. The clinical studies focus upon the immune response of infected individuals, and factors that influence the immune response. Experimental infections with the parasite in a newly recognized animal host, the jird (Meriones unguiculatus), have been initiated recently. Also, collaborative clinical studies are being carried out in Brazil. The recombinant gene product (S4) reported last year could not be cleanly separated from its pMAL vector so a new cDNA library was prepared. Evidence for differences between L3s of strongyloides and related nematodes are being examined by analysis of PCR products of internal spacer regions of ribosomal DNA genes. Analysis of cytokine responses in 17 Brazilian patients with S. stercoralis infections, with or without concomitant HTLV-1 infection, have disclosed elevated INF-gamma responses in those with HTLV-1. Immediate skin tests are being done on these and additional patients. In preliminary studies it appears that IgG4 antibodies decline much earlier than total IgG antibodies in treated strongyloidiasis patients. Strongyloides infections of jirds are not easily maintained in serial passage, but this experimental host may be useful for certain studies that are impractical in dogs or monkeys.
