Partial immune restoration may be obtained with highly active antiretroviral therapy (HAART), but specific anti-HIV-1 immune responses do not appear to improve substantially. We have demonstrated that a soluble factor(s) induced by a mixture of inactivated influenza and bacterial vaccines called polyantigenic immunomodulator (PAI), possesses strong immunoregulatory and anti-HIV-1 activities. In the present study, we show that culture fluids from both PAI-stimulated peripheral blood mononuclear cells (PBMC) and CD8+ T-cells of HIV-1 infected patients were able to suppress HIV-1 replication in an MHC-unrestricted fashion. The PAI-induced antiviral activity was eliminated when culture fluids were pre-heated at 100oC for 10 min. and it is associated with induction of IFN-Γ, MIP-1α, MIP-1β, and RANTES production, but inhibition of IL-10. Furthermore, this induction is dependent on the immunological status (CD4:CD8 ratio) of the HIV-1 infected patient. Taken together, our results suggest that the MHC-unrestricted HIV-1 suppression that is induced by culture fluids from PAI-stimulated PBMC may result from the stimulation of immune cell subpopulations to produce a heat-labile antiviral soluble factor(s), which in turn modulate cytokine and β-chemokine production. The identification of this PAI-induced soluble factor(s) may have major therapeutic potential.