Reovirus and infectious bursal disease virus are among the naturally occurring viruses that cause immunosuppression in chickens. Both viruses cause necrotic lesions in the bursa of Fabricius and may destroy B cells. This may explain their ability to cause humoral immune suppression. The mechanism(s) of virus-induced suppression of cellular immunity is not well understood. Both viruses inhibit the mitogenic response of T cells in chickens. We have noted that this inhibition may be mediated by inhibitory cytokines such as transforming growth factor-beta and nitric oxide produced by activated macrophages. Preliminary studies have indicated that pretreatment of chickens with an immunomodulator, acemannan, reduced the reovirus-induced inhibition of T cells.
ASJC Scopus subject areas
- Animal Science and Zoology