S. Sabbaj et al., Cytokine profiles in seronegative volunteers immunized with a recombinant canarypox and gp120 prime-boost HIV-1 vaccine, AIDS, 14(10), 2000, pp. 1365-1374
Objectives: To study memory T cell proliferative responses and cytokine pro
files induced in HIV-1 seronegative volunteers immunized with a live recomb
inant canary-pox vector expressing HIV-1 antigens (ALVAC-HIV) and boosted w
ith a recombinant gp120 subunit vaccine.
Design: HIV-specific T cell proliferative responses and cytokines were meas
ured 2 weeks after vaccination. Cytokines secreted by T helper 1 cells (Th1
) [interleukin (IL)-2 and interferon-gamma (IFN-gamma)] and T helper 2 (Th2
) cells (IL-4, IL-5, IL-6, and IL-10) were assessed both at the mRNA and th
e protein level.
Methods: Peripheral blood mononuclear cells (PBMC) were stimulated in vitro
with HIV antigens. Subsequently, T cell proliferation was measured in a st
andard lymphoproliferation assay; secreted cytokines were measured using an
enzyme-linked immunosorbent assay and upregulation of cytokine mRNA was me
asured using reverse transcriptase polymerase chain reaction.
Results: All individuals who had received ALVAC-HIV followed by the protein
vaccine exhibited HIV-l-specific T cell proliferative responses. Moreover,
the PBMC of all prime-boost vaccinated individuals produced detectable IFN
-gamma and IL-10 in response to stimulation with HIV-1 envelope glycoprotei
n antigens; 83% also had detectable levels of IL-2 and IL-6, 71% had detect
able levels of IL-4, and 86% had detectable levels of IL-5.
Conclusions: These data indicate that this vaccination regimen was inducing
both Th1- and Th2-type responses to HIV-1 envelope antigens. This prime-bo
ost vaccination approach elicited T cell help for the generation of cytotox
ic T lymphocyte responses as well as help for antibody production and so pr
omises to generate a broad HIV-l-specific immune response. (C) 2000 Lippinc
ott Williams & Wilkins.