Fbp from other bacteria, FnBPA and FnBPB from Staphylococcus aureus and Sfb1 from S Staphylococcus pyogenes, are known to contain a common motif that bind to the N-terminal type I module of Fn (28, 29). Another Fbp, BBK32 from Borrelia burgdorferi, is reported to bind to III1–3 as well as to I1–5 of Fn (30, 31). BBK32, however, has the capacity to make an aggregation of Fn by virtue of binding to III1–3 of Fn. Unlike BBK32, neither FbpA nor FbpB from C. perfringens has such an Fn aggregating capacity (data not shown). It is https://www.selleckchem.com/products/dabrafenib-gsk2118436.html known that Fn aggregates when Fn is incubated with III1-C peptide (32). This means that Fn binds to III1-C peptide. In fact, in the present study, Fn reacted

with immobilized III1-C peptide. The binding of Fn to III1-C was inhibited by the presence of either rFbpA or rFbpB (Fig. 5). This result suggests that C. perfringens Fbps Z-VAD-FMK may inhibit Fn-matrix formation in vivo. We thank Takahiro Hiraiwa, Tatsuma Tsuchiya and Masaya Okuda for generating the monoclonal

antibodies. We also thank Kana Harutsumi for technical support. “
“A balance of inhibitory and activating signals determines the function of dendritic cells (DCs) in the immune response, which may be regulatory or stimulatory. Defects of inhibitory receptor FcγRIIb are involved in the pathogenesis of autoimmune diseases such as systemic lupus erythematosus (SLE), in which high levels of circulating immune complexes (IC) exist. Our previous study showed that IC/Ig can suppress TLR4-triggered inflammatory Nintedanib (BIBF 1120) responses in macrophages via FcγRIIb. This led us to question whether IC/Ig can polarize FcγRIIb-overexpressing DCs (DC-FcγRIIb) to be tolerogenic, thus attenuating lupus progression once infused in vivo. First, we found that IC/Ig markedly inhibited LPS- or CpG-induced DC maturation, enhanced tolerogenicity of DCs via FcγRIIb, and induced massive prostaglandin E2 (PGE2) secretion from DCs, both contributing to T-cell hyporesponsiveness. Endogenous Ig and lupus-derived IC also exhibited the same effect.

DC-FcγRIIb, transfected with recombinant adenovirus encoding FcγRIIb, displayed enhanced tolerogenic function and produced more PGE2 in the presence of IC, thus further inhibiting T-cell responses. Importantly, in vivo infusion with DC-FcγRIIb significantly reduced kidney damage and prolonged the survival of lupus-prone MRL/lpr mice either before or after the onset of clinic lupus. Therefore, administration of DC-FcγRIIb may be a new approach to attenuate lupus progression. As a highly heterogeneous population, DCs not only play an important role in initiating and enhancing immune response but also contribute to the maintenance of tolerance via various mechanisms, including direct inhibition of T-cell response, induction of T-cell anergy or Treg and directing Th subset polarization 1–7.