MECHANISM OF GAMMA-DELTA T-CELL-MEDIATED INHIBITION OF STEM-CELL DIFFERENTIATION IN-VITRO - POSSIBLE RELEVANCE FOR MYELOSUPPRESSION IN HIV-INFECTED INDIVIDUALS
Ts. Dobmeyer et al., MECHANISM OF GAMMA-DELTA T-CELL-MEDIATED INHIBITION OF STEM-CELL DIFFERENTIATION IN-VITRO - POSSIBLE RELEVANCE FOR MYELOSUPPRESSION IN HIV-INFECTED INDIVIDUALS, Cellular immunology (Print), 184(1), 1998, pp. 26-36
We investigated whether gamma delta T cells contribute to the suppress
ion of myelopoiesis in HlV infection. Freshly isolated gamma delta T c
ells from HIV seropositive patients suppressed CFU-GM growth in vitro.
Preactivation of gamma delta T cells with IL-2 and/or IL-15 further r
educed the number of CFU-GM Natural killer cells and to a lower extent
CD4(+) and CD8(+) cells also inhibited CFU-GM growth. In contrast to
gamma delta T cells, this effect was not dependent on IL-15 or IL-2 pr
eactivation. Moreover, no enhanced inhibitory effect of CD56(+) and CD
4(+) cells was observed in HIV+ subjects compared to HIV- donors. The
myelosuppressive effect of supernatants of gamma delta T cells could b
e inhibited by antibodies against IFN-gamma or TNF-alpha. Accordingly,
we found increased numbers of IFN-gamma or TNF-alpha secreting CD8(+)
gamma delta T cells in HIV+ patients. We conclude that the increased
fraction of activated gamma delta T cells producing myelosuppressive c
ytokines might contribute to the dyshematopoiesis frequently observed
in HIV-infected individuals. (C) 1998 Academic Press.