Genes encoding vanillin dehydrogenase (vdh) and vanillate O-demethylase (vanAB) were identified in Rhodococcus jostii RHA1 using gene disruption and enzyme activities. During growth on vanillin or vanillate, vanA was highly upregulated while vdh was not. This study contributes to our understanding of lignin degradation by RHA1 and other actinomycetes.

CpG-containing oligodeoxynucleotides (CpG ODN) stimulates spleen cells in vitro and induces IFNγ secretion mostly from NK cells, whereas purified NK cells are not stimulated by CpG ODN. IL-12 neutralization inhibits NK cell IFNγ production, and IL-12 knockout mouse spleen cells stimulated with CpG ODN produce very little IFNγ, indicating that IL-12 is required. Depletion of macrophages and DC has no effect, whereas neutrophil depletion dramatically decreases both IL-12 and IFNγ production by spleen cells, indicating that neutrophils are a key source of IL-12. NK cells in B cell-deficient mouse spleen secrete higher levels of IFNγ than wild type spleen cells, and B cell depletion enhances NK cell IFNγ production, indicating that B cells are suppressive. CD5+ B cells secrete IL-10 in response to CpG ODN. The neutralization of IL-10 increases IFNγ and IL-12 production by CpG ODN-stimulated spleen cells, and B cell-deficient splenocytes produce more IL-12 than WT splenocytes. Furthermore, exogenously added IL-10 effectively inhibits CpG ODN-induced IL-12 production by purified neutrophils, and IL-12/IL-18 induced stimulation of purified NK cells. Therefore, CD5+ B cells produce IL-10 and suppress CpG ODN-mediated NK cell IFNγ production by inhibiting neutrophil IL-12 production as well as by directly acting on activated NK cells themselves.