Cytotoxic T lymphocyte (CTL) responses targeting specific HIV proteins, in particular Gag, have been associated with relative control of viral replication in vivo. However, Gag-specific CTL can also be detected in individuals who do not control the virus and it remains thus unclear how Gag-specific CTL may mediate the beneficial effects in some individuals but not in others. Here, we used a 10mer peptide set spanning HIV Gag-p24 to determine immunogen-specific T-cell responses and to assess functional properties including functional avidity and cross-reactivity in 25 HIV-1 controllers and 25 non-controllers without protective HLA class I alleles. Our data challenge the common belief that Gag-specific T cell responses dominate the virus-specific immunity exclusively in HIV-1 controllers as both groups mounted responses of comparable breadths and magnitudes against the p24 sequence. However, responses in controllers reacted to lower antigen concentrations and recognized more epitope variants than responses in non-controllers. These cross-sectional data, largely independent of particular HLA genetics and generated using direct ex-vivo samples thus identify T cell responses of high functional avidity and with broad variant reactivity as potential functional immune correlates of relative HIV control.

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A selective polyclonal antibody directed toward the C-terminal decapeptide common to the a subunits of Gq and Gil G proteins (Gaq/Ga,ii,) was prepared and used to investigate the subcellular distribution of these proteins in WRK1 cells, a rat mammary tumor cell line. In immunoblots, the antibody recognized purified Gaq and Gall proteins and labeled only two bands corresponding to these a subunits.

Abstract. HIV infection, if left untreated, leads in most cases to the development of wide immune deterioration, opportunistic infections and eventually AIDS and death. The identification of individuals who despite persisting infection show no or few signs of HIV disease progression has spurred hopes that an effective HIV vaccine could be attainable. The design of such a vaccine will greatly depend on the precise definition of disease markers, host genetic and immune characteristics that mediate relative in vivo control of this virus. Accordingly, a number of viral factors and host genetic characteristics have been shown to play a crucial role in the control of HIV disease by delaying progression to AIDS or even preventing infection. There is also an improved understanding of humoral and cellular immune responses in terms of specificity, functional repertoire, longevity and tissue distribution and their ability to contain HIV replication. However, the definition of good immune correlates unequivocally and causally associated with protection or disease progression remains elusive. Here we review work on viral factors, host genetic markers and immunological determinants that have been identified in individuals with superior control of HIV infection or in subjects who remain uninfected despite frequent exposure to the viral pathogen.