ABSTRACT
We determined the capacity of vaccinia virus recombinants expressing individual rotavirus genes to induce virus-specific cytotoxic T lymphocytes (CTLs) in mice. Mice were orally inoculated with vaccinia virus recombinants containing genes which encode rotavirus outer capsid proteins vp4 or vp7, single-shelled virus proteins vp1, vp2, or vp6, or rotavirus nonstructural proteins NS53, NS35, NS28, or NS26/NS12. We found that (i) the greatest frequencies of virus-specific CTLs were induced by vaccinia virus recombinants expressing vp7, (ii) transport of vp7 beyond the endoplasmic reticulum was not necessary for induction of CTLs, (iii) recombinants expressing vp7 induced CTLs which reacted with different rotavirus serotypes, and (iv) CTLs were induced among both intestinal and nonintestinal lymphocytes after oral inoculation. These findings may be relevant to vaccine strategies which utilize vectors expressing individual rotavirus genes.
Subject(s)
Genes, Viral , Rotavirus/immunology , T-Lymphocytes, Cytotoxic/microbiology , Vaccinia virus/genetics , Administration, Oral , Animals , Cytotoxicity, Immunologic , Female , Gene Expression Regulation, Viral , Lymphocyte Activation , Mice , Mice, Inbred C57BL , Recombinant Proteins/immunology , Recombination, Genetic , Rotavirus/genetics , Serotyping , T-Lymphocytes, Cytotoxic/immunology , Vaccinia virus/immunology , Viral Proteins/genetics , Viral Proteins/immunologyABSTRACT
Cytotoxic T lymphocytes (CTLs) generated in mice orally inoculated with rotaviruses lyse target cells infected with different rotavirus serotypes (cross-reactive CTLs). Using vaccinia virus recombinants expressing individual rotavirus proteins from two different rotavirus serotypes, we found that cross-reactive CTLs recognize target cells expressing outer capsid protein vp7 better than those expressing outer capsid protein vp4 or inner capsid protein vp6. These findings may be relevant to vaccine strategies which include immunization with reassortant rotaviruses or viral or bacterial vectors expressing individual rotavirus proteins. The region or regions of vp7 which are antigenically conserved among different rotavirus serotypes and recognized by cross-reactive CTLs remain to be determined.
Subject(s)
Antigens, Viral/immunology , Capsid Proteins , Capsid/immunology , Membrane Glycoproteins/immunology , Rotavirus/immunology , T-Lymphocytes, Cytotoxic/immunology , Animals , Cross Reactions , Cytotoxicity, Immunologic , Immunity, Cellular , Mice , Mice, Inbred C57BL , SerotypingABSTRACT
The immunologic basis of homotypic and heterotypic protection by immunization with two candidate rotavirus vaccine strains (simian strain RRV and bovine strain WC3, respectively) was investigated. Mice were orally inoculated with RRV, and 6 d later splenic lymphocytes lysed target cells infected with RRV (serotype 3) but not with human rotavirus serotypes 1 or 2; 4 w after inoculation, cytotoxic T lymphocytes (CTLs) generated in vitro from CTL precursors were also strain-specific. Also, the frequency of RRV-specific CTLs from CTLp after RRV immunization was 20-fold greater than that of cross-reactive CTLs. Inoculation of mice with WC3 (serotype 6), on the other hand, produced cross-reactive CTLs from CTLp at 4 w; CTLs lysed target cells infected with WC3 or human serotypes 1, 2, or 3 to the same extent. The frequency of cross-reactive CTLs after WC3 immunization was greater than or equal to 20-fold greater than that of WC3-specific CTLs. Cross-reactive, rotavirus-specific CTLs induced after WC3 immunization may in part explain the immunologic basis of protection against heterotypic challenge.
