Aggregated IgG inhibits the differentiation of XXXX fibrocytes.

@entity1 @entity32 @entity222 @entity10685 @entity5750 @entity565 @entity3794 @entity2631 @entity10255 @entity2729 @entity669
Fibrocytes are fibroblast-like cells, which appear to participate in wound healing and are present in pathological lesions associated with @entity565 , @entity3794 , and @entity2631 . Fibrocytes differentiate from @entity5750 + peripheral blood monocytes, and the presence of serum delays this process dramatically. We previously purified the factor in serum, which inhibits fibrocyte differentiation, and identified it as @entity2729 ( @entity2729 ). As @entity2729 binds to Fc receptors for immunoglobulin G (IgG; Fc gammaRs), Fc gammaR activation may be an inhibitory signal for fibrocyte differentiation. Fc gammaR are activated by aggregated IgG, and we find aggregated but not monomeric, human IgG inhibits @entity1 fibrocyte differentiation. Monoclonal antibodies that bind to @entity10685 ( @entity10685 ) or Fc gammaRII ( @entity222 ) also inhibit fibrocyte differentiation. Aggregated IgG lacking Fc domains or aggregated IgA, IgE, or IgM do not inhibit fibrocyte differentiation. Incubation of monocytes with @entity2729 or aggregated IgG inhibited fibrocyte differentiation. Using inhibitors of protein kinase enzymes, we show that @entity10255 - and Src-related @entity669 kinases participate in the inhibition of fibrocyte differentiation. These observations suggest that fibrocyte differentiation can occur in situations where @entity2729 and aggregated IgG levels are low, such as the resolution phase of @entity32 .
