EK-1A (51), EK-5A (52) and EK-15A (53), were isolated from Euphorbia kansui, and not only demonstrated latent reactivation efficacies in vitro and ex vivo at nanomolar concentrations but also could inhibit acute HIV-1 infection via down-regulation of the expression of CCR5 and CXCR4, two cell surface HIV co-receptors. The gene discussed is CCR5; the disease is HIV-1 infection.