In the present study, recombinant, fully glycosylated simian IL-7 (50 μg/kg, s.c., once weekly for 7 weeks) was administered to 6 rhesus macaques throughout the acute phase of infection with a pathogenic SIV strain (mac251); 6 animals were infected at the same time and served as untreated controls. The gene discussed is IL7; the disease is infection.