[Responses of kids to monocytes infected in vitro by the caprine arthritis-encephalitis virus].

Retroviruses from small ruminants are spread between susceptible animals by mononuclear phagocytes which are also virus targets. Young seronegative goats were inoculated with in vitro infected monocytes producing caprine arthritis encephalitis virus (10(5) cells/animal) by intravenous route corresponding to 10(5) syncytia forming units. After 3 months the same goats received dexamethasone treatment (5 mg/animal each 2 days over a 10-day period). The observed immune response differed if the animal was infected with its own cells or with homologous cells. Before dexamethasone treatment, antibody production evaluated by gel precipitation, ELISA or western blot was delayed in autologous by comparison with homologous conditions. After dexamethasone treatment, the appearance of infectious monocytes in blood and subsequent arthritis were observed in all animals in homologous conditions and only in 1 animal out of 3 in autologous conditions. Host reaction to the infected cells determines virus expression at the time of contamination.