In vivo depletion of CD8+ cells does not affect primary maedi visna virus infection in sheep

T-cells have been implicated both, in promoting and reducing viral replication during lentivirus infection. CD8+ lymphocytes are believed to be important in controlling viral load through direct killing of virus-infected cells and by secretion of inhibitory chemokines and cytokines. To evaluate the role of CD8+ T-cells in the induction and control of the primary phase of a lentivirus infection, we have used a non-T-cell tropic lentivirus, maedi-visna virus (MVV), to study the initial pathogenesis and subsequent immune responses in sheep depleted in vivo of CD8+ cells. Sheep were depleted of CD8+ cells in both blood and efferent lymph for up to 14 days. No difference in MVV replication was observed in either the draining efferent lymph or lymph node of these sheep. Surprisingly, these animals displayed a normal induction of pCTL whereas the virus-specific proliferative responses were reduced. This could reflect either that a proportion of functional CD8+ lymphocytes remained in these animals, as suggested by the appearance of pCTLs, or that CD8+ cells are not required for control of primary MVV infection.     

Isolation of Salmonella victoria from a cow

Extract

At the end of January 1972, specimens were submitted to this laboratory from a cow in the Geraldine district, which was one of three that died suddenly after transfer to a new, clover-dominant pasture. All apparently died from the same cause and post-mortem examination revealed reddened external mucosae, froth at nostrils, and gas distension of the carcasses. In addition, there was mild reddening of abomasal mucosa, severe reddening of intestinal mucosa, and congestion of the liver and lungs. Enterotoxaemia, salmonellosis, blood poisoning or irritant poisoning was suspected.