Cytokines produced by cells of the immune system, including macrophages,
can influence inflammatory responses to viral infection. This has been
exploited by viruses, which have developed strategies to direct the
immune response towards ineffective responses. African swine fever virus
(ASFV) is a double-stranded DNA virus that infects macrophages of
domestic swine. In this study, primary cells of monocyte macrophage
lineage were obtained from the lungs, peritoneum or blood of domestic
swine and, after infection with ASFV, supernatants were tested for
cytokines using biological assays. The cytokine transforming growth
factor-beta (TGF-beta) was detected after infection of macrophage
preparations, but tumour necrosis factor (TNF) and interleukin-1 (IL-1)
were not detected. ASFV-infected and uninfected macrophage populations
were also tested to assess their ability to respond to cytokines by
enhancing production of superoxide in the respiratory burst mechanism.
Responses to interferon-gamma (IFN-gamma) and lipopolysaccharide (LPS)
were suppressed in macrophage populations infected with virus, even at
low multiplicities of infection. Addition of TGF-beta to uninfected
macrophages resulted in a similar suppression of response, but antibody
to TGF-beta did not prevent suppression induced by virus. These results
are discussed in relation to the pathology of African swine fever.
Source:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1364015/
