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