Experimental infection of pigtailed macaques with a simian rotavirus, YK‐1

Abstract

Experimental rotavirus infection was investigated in pigtailed macaques to study the infectivity, immunity, and pathogenesis of rotavirus. A challenge virus, YK‐1, was administered intragastrically to four seronegative macaques (age: 11–16 months). Although none of the monkeys developed diarrhea, an active infection occurred with high titers of rotavirus antigen detected in stools 2–10 days after challenge. These animals developed rotavirus‐specific antibody responses similar to those seen following primary exposure to rotavirus. YK‐1 was then inoculated in four seropositive macaques (age: 14–16 months). All animals shed viral antigen in their stool, but the titers and duration were significantly less when compared to seronegative macaques. When rechallenged 28 days after initial YK‐1 challenge, the macaques demonstrated significant protection against reinfection. All seropositive animals developed a rise in rotavirus‐specific serum and fecal antibodies during YK‐1 challenge and rechallenge. To independently assess the role of age and preexisting IgG titers to rotavirus, a 4‐month‐old seronegative and 6‐month‐old seropositive macaque were inoculated with YK‐1. The seronegative macaque shed high titers of virus for 9 days, while the seropositive macaque shed only 3 days and in low titer. These data suggest that a primate model of rotavirus infection using the YK‐1 strain may be useful in examining the immune response and protection from infection in pigtailed macaques and indicate that levels and duration of shedding may provide a good measure of protection from natural infection and from that induced by oral or parenteral vaccines. J. Med. Virol. 75:616–625, 2005. Published 2005 Wiley‐Liss, Inc.