Temporal association of interferon- αand p27 core antigen levels in sera of simian immunodeficiency virus infected monkeys

We report the temporal association of interferon (IFN) and p27 core antigen production during experimental simian immunodeficiency virus Delta B670 (SIV) infection in rhesus monkeys. Peak serum IFN-α levels (10 2.8–5.0U/ml) occurred 10 days post infection (p.i.) and peak p27 levels (3.1–34.4 ng/ml) occurred 10–14 days p.i. Acid-stable IFN-α (10 1.6–2.5U/ml) was detected 3–5 days before p27 in sera from three monkeys and was detected with p27 (0.06–3.06 ng/ml) in four monkeys during the primary infection. Serum IFN-α and p27 levels became undetectable 24–40 days p.i. Two monkeys remained asymptomatic for SIV after the primary p27 antigenaemia, three monkeys had recrudescent (3–4 months p.i.) acid stable interferonaemias (10 1–2.5U/ml) with p27 antigenaemias (0.06–2.7 ng/ml) that persisted until death, and two monkeys had acute SIV infections (died ≤7 months p.i.) with persistent acid-stable interferonaemia (10 1.6–2.5U/ml) and p27 antigenaemia (6—9 ng/ml). Our results indicate that the detection of acid-stable IFN-α in serum is closely associated with detection of p27 ( P=0.0001) and suggest that detection of acid-stable IFN-α and p27 core antigen is indicative of active SIV infection.