Differing T-cell requirements for recombinant retrovirus vaccines.
Friend murine leukemia virus is a retrovirus complex that induces rapid erythroleukemia and immunosuppression in susceptible strains of adult mice. Using this model, we directly examined the T-cell subsets required for a protective retrovirus vaccine. Paradoxically, recovery in mice immunized with a chimeric envelope containing only T-helper (TH) and B-cell epitopes was dependent on CD8+ T cells as well as CD4+ T cells despite the fact that the vaccine contained no CD8+ cytolytic T-lymphocyte (CTL) epitopes. However, the requirement for CD8+ T cells was overcome by inclusion of additional TH and B-cell epitopes in the immunizing protein. These additional epitopes primed for more rapid production of virus-neutralizing antibody which appeared to limit virus spread sufficiently to protect even in the absence of CD8+ T cells. Inclusion of an immunodominant CTL epitope in the vaccine was not sufficient to overcome dependence on CD4+ T cells. These data suggest that TH priming is more critical for retrovirus immunity than CTL priming.
Hasenkrug
K J
KJ
Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, Hamilton, Montana 59840, USA.
Brooks
D M
DM
Nishio
J
J
Chesebro
B
B
D000595:Amino Acid Sequence; D000818:Animals; D000956:Antigens, Viral / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D000939:Epitopes / Q000032:analysis; D005260:Female; D005622:Friend murine leukemia virus / Q000276:immunology*; D008212:Lymphocyte Depletion; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D014611:Vaccination; D014759:Viral Envelope Proteins / Q000235:genetics / Q000276:immunology; D014765:Viral Vaccines / Q000276:immunology*
D000956:Antigens, Viral; D000939:Epitopes; D011993:Recombinant Fusion Proteins; D014759:Viral Envelope Proteins; D014765:Viral Vaccines