Previous Article | Next Article ![]()
J. Virol., 02 1996, 1072-1079, Vol 70, No. 2
MG von Herrath, M Yokoyama, J Dockter, MB Oldstone and JL Whitton
Although primary antiviral CD8+ cytotoxic T lymphocytes (CTL) can be
induced in mice depleted of CD4+ T cells, the role of CD4+ T lymphocytes in
the generation and maintenance of antiviral memory CTL is uncertain. This
question, and the consequences upon vaccine-mediated protection, were
investigated in transgenic CD4 knockout (CD4ko) mice, which lack CD4+ T
lymphocytes. Infection of immunocompetent C57BL/6 mice with lymphocytic
choriomeningitis virus (LCMV), or with recombinant vaccinia viruses bearing
appropriate LCMV sequences, induces long-lasting protective immunity,
mediated mainly by antiviral CD8+ CTL. Here we report two important
findings. First, LCMV-specific CD8+ memory CTL are maintained at
considerably lower levels in CD4ko mice than in normal C57BL/6J mice; we
demonstrate a reduction in precursor CTL evident as soon as 30 days
postimmunization and declining, by day 120, to levels 1 to 2 log units
below those in normal mice. Thus, CD4+ T cells appear to be important to
the generation and maintenance of their CD8+ counterparts. Second, this
reduction has an important biological consequence; compared with
immunocompetent mice, CD4ko mice immunized with vaccinia virus recombinants
expressing nucleoprotein or glycoprotein of LCMV are less effectively
protected from subsequent LCMV challenge. Thus, this study underscores the
potential importance of CD4+ T lymphocytes in generation of appropriate
levels of CD(8+)-cell-mediated immunoprotective memory and has implications
for vaccine efficacy in individuals with immune defects in which CD4 levels
may be reduced, such as AIDS.
Copyright © 1996, American Society for Microbiology
CD4-deficient mice have reduced levels of memory cytotoxic T lymphocytes after immunization and show diminished resistance to subsequent virus challenge
Department of Neuropharmacology, Scripps Research Institute, La Jolla, California 92037, USA.
This article has been cited by other articles:
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»