Exposure to HIV-1 Tat1-86 increases progenitor secretion of a select group of chemokines. Cells were treated at 5 days after plating with morphine (M), Tat (T), gp120 (G), and naloxone (N) either alone or in combinations as indicated. Of 23 factors tested, 10 were secreted by unstimulated cells (see Table 1). Only RANTES, MIP-1α, and MIP-1β showed a significant change in concentration after 12 h treatment. Cells responded to Tat, but not to gp120. There was no synergistic response of concurrent exposure to either morphine or gp120. MCP-1 showed a similar trend towards a Tat response, but the effect was not significant. * p<0.05; ** p<0.01; *** p<0.001 vs. untreated control cells (C), ANOVA and post-hoc Bonferroni’s test. N=6 independent cultures.