IgA Inducing Protein (IGIP)

Over the last several years, there has been a great deal of progress in characterizing the role of dendritic cells (DCs) in the activation and modulation of B cells. DC-secreted chemokines can induce B cell trafficking to the lymph nodes. DC-produced survival factors such as B cell-activating factor of the TNF family and a proliferation-inducing ligand have been shown to be essential for B cell maturation, but have also been implicated in class-switch recombination and B cell lymphoma survival. Recently added to this list of DC-derived factors effecting B cells is IgA-inducing protein (IGIP). Naive B cells cultured with exogenous recombinant human IGIP produced IgA in greater quantities than nonstimulated controls. IGIP stimulation drives the production of mu-alpha switch circles from IgM(+)IgD(+) naive human B cells, indicating its role as an IgA switch factor.