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Increased susceptibility of mice infected with Schistosoma mansoni to recombinant vaccinia virus: association of viral persistence with egg granuloma formation.




 

Eur J Immunol. 1994 Dec;24(12):3050-6. Unique Identifier : AIDSLINE

BALB/c mice infected 7 weeks previously with Schistosoma mansoni and challenged with a recombinant vaccinia virus vPE16 expressing the human immunodeficiency virus envelope protein gp160 show a marked delay in hepatic viral clearance as compared to mice infected with vPE16 alone. This increase in viral persistence is accompanied by reduced gp120-specific Th1-associated cytokine responses as well as by impaired cytotoxic T lymphocyte (CTL) activity against targets expressing epitopes of the same antigen. To investigate the contribution of these defects to the observed delay in clearance of recombinant vaccinia virus, animals were challenged with vPE16 at different times following S. mansoni infection, and virus titers in tissues and viral-specific immune responses were measured simultaneously in the same animals. While normal resolution of virus occurred in schistosome-infected mice prior to parasite egg deposition, persistence within the liver was observed in animals challenged during the onset and peak phase of granuloma formation (6 to 8 weeks after S. mansoni infection). At later times, when schistosomiasis is in its chronic phase, normal viral clearance returned. This time course of viral resolution correlated in part with the observed pattern of decreased Th1 cytokine production toward viral antigens but was clearly less temporally related to the defect in virus-specific CTL activity. Immunohistochemical staining of liver sections from vaccinia/S. mansoni co-infected mice with polyclonal anti-vaccinia antibodies revealed that viral epitopes are localized primarily within granulomas. These experiments suggest that egg granulomas, by providing a microenvironment for viral expression, in combination with the cytokine imbalance present during schistosome infection, can promote the expansion of vaccinia virus and possibly other viral agents.

Animal Cytokines/METABOLISM Cytotoxicity, Immunologic DNA, Recombinant Female Granuloma/IMMUNOLOGY Immunity, Cellular Liver/MICROBIOLOGY/PARASITOLOGY Lung/PARASITOLOGY Mice Mice, Inbred BALB C Schistosoma mansoni/IMMUNOLOGY Schistosomiasis mansoni/*IMMUNOLOGY/PATHOLOGY T-Lymphocytes, Cytotoxic/IMMUNOLOGY Vaccinia/*IMMUNOLOGY Vaccinia Virus Virus Replication JOURNAL ARTICLE



 




Information in this article was accurate in April 30, 1995. The state of the art may have changed since the publication date. This material is designed to support, not replace, the relationship that exists between you and your doctor. Always discuss treatment options with a doctor who specializes in treating HIV.