Higher macrophage inflammatory protein (MIP)-1alpha and MIP-1beta levels from CD8+ T cells are associated with asymptomatic HIV-1 infection

Abstract

To test the hypothesis that beta-chemokine levels may be relevant to the control of HIV in vivo, we compared RANTES, MIP-1alpha, and MIP-1beta production from purified CD8(+) T cells from 81 HIV-infected subjects and from 28 uninfected donors. Asymptomatic HIV(+) subjects produced significantly higher levels of MIP-1alpha and MIP-1beta, but not RANTES, than uninfected donors or patients that progressed to AIDS. In contrast, beta chemokines in plasma were either nondetectable or showed no correlation with clinical status. The high beta-chemokine-mediated anti-HIV activity was against the macrophage tropic isolate HIV-1(BAL), with no demonstrable effect on the replication of the T-cell tropic HIV-1(IIIB). These findings suggest that constitutive beta-chemokine production may play an important role in the outcome of HIV-1 infection.

Figure 1

Comparison of β-chemokine production by CD8⁺ T cells from HIV-1-infected cases stratified by CD4⁺ T-cell count and uninfected cases. CD8⁺ T cells were isolated from HIV⁺ individuals with CD4⁺ T-cell counts less than (Group A) or greater than (Group B) 200 cells per μl. CD8⁺ T cells were also obtained from uninfected donors (Group C) for further comparisons. The cells were isolated from freshly collected PMBCs by immunomagnetic beads, and 2 × 10⁶ cells per ml were activated with PHA (1 μg/ml) and Rh IL-2 (10 ng/ml). β-Chemokine production by CD8⁺ T cells was analyzed in the culture supernatants after 3 days of PHA stimulation by ELISA. The indicated p-values were generated from t tests. For analyses of MIP-1α: *, P = 0.012, #, P = 0.004. For analyses of MIP-1β: *, P = 0.001, #, P = 0.008. The differences in RANTES values were not significant. Bars indicate the standard errors of the means.

Figure 2

Lower production of MIP-1α and MIP-1β by CD8⁺ T cells from HIV-1⁺ individuals with clinical diagnosis of AIDS defined by CDC criteria compared with asymptomatic subjects. CD8⁺ T cells were isolated from HIV⁺ individuals who were clinically asymptomatic or diagnosed with AIDS based on Kaposi's sarcoma or opportunistic infection. The cells were isolated, cultured, and analyzed as described in Fig. 1 and in the text. The indicated p-values were generated from t tests. For analyses of MIP-1α: P = 0.035 or MIP-1β: P = 0.016. The difference in RANTES values was not significant. Bars indicate the standard errors of the means.

Figure 3

The effect of anti-β chemokine NAb on the CD8⁺ T-cell-mediated antiviral activity against the macrophage tropic HIV-1_BAL. The CD8⁺ T-cell culture supernatants obtained from 8 HIV⁺ subjects were assayed for antiviral activity in the presence of either a nonspecific control antibody (300 μg/ml) (■) or a mixture of NAb specific to RANTES (100 μg/ml), MIP-1α (100 μg/ml), and MIP-1β (100 μg/ml) (▨). The neutralization test was performed by incubating the antibody (R & D Systems) for 30 min at room temperature. Antibodies were added at the initiation of the culture and were replaced after 48 h on medium exchange. The effect on HIV replication was determined at day 8 by p24 ELISA.