FIG 3.

Roles of BAFF and APRIL during infection. Many pathogens induce the expression of BAFF and APRIL in myeloid cells or epithelial cells through the engagement of pattern recognition receptors by pathogen-associated molecular patterns. In addition, pathogen-induced type I and II IFNs can elicit BAFF and APRIL expression. The main consequence of elevated BAFF and APRIL expression levels is the activation of B cells and the induction of pathogen-specific antibody production. Unlike most pathogens, C. neoformans has been shown to suppress the expression of BAFF in human PBMCs. Diminished BAFF expression in C. neoformans infection is likely a virulence mechanism developed by the fungus because C. neoformans-infected patients have low levels of circulating immunoglobulins. TLRs, Toll-like receptors; GDH, glutamate dehydrogenase; CIDR1α, cysteine-rich interdomain region 1α; HCV, hepatitis C virus; RSV, respiratory syncytial virus; Nef, negative factor; IFNγR, interferon gamma receptor; dsRNA, double-stranded RNA.