Expression of Semaphorin4C by Th2-stimulated B cells
© Drolet et al; licensee BioMed Central Ltd. 2010
Published: 4 November 2010
Semaphorins are a family of proteins implicated in neurogenesis, angiogenesis and axonal migration. Previous work from our laboratory has shown that Th2-stimulated B cells express a unique semaphorin, SEMA4C. Given the roles of other semaphorins, we hypothesized that SEMA4C was expressed on Th2-stimulated B cells and might play a role in B cell trafficking and tissue homing therefore being expressed stronger in terminally differentiated B cells, such as memory and plasma cells.
Experiment and results
B cells were purified from tonsils removed from children undergoing routine tonsillectomy. They were cultured for 24 hours or 7 days at a concentration of 5X104 cells/mL in complete medium in the presence of αCD40 with either IFNγ, IL-4, IL-21 or both IL-4 and IL-21. RNA was extracted, cDNA was made, and SEMA4C mRNA was amplified by qPCR and compared to the housekeeping gene GAPDH. After 24h culture, SEMA4C mRNA expression was detected only in IL-4-stimulated cells but after 7 days, the expression was much stronger in both conditions containing IL-21, and decreased in IL-4-only stimulated cells.
SEMA4C is induced in B cells upon Th2 stimulation but increases further upon follicle-like differentiation triggered by IL-21. This data confirms that SEMA4C is specific to terminally-differentiated B cells and supports our hypothesis that it might play a role in B-cell trafficking and homing in peripheral tissue follicles. SEMA4C could therefore be a key player in local allergic inflammation.
This article is published under license to BioMed Central Ltd.