Discussion
S1P signalling influences peritoneal B1 B cell migration. S1P&sub4; deficiency alters the composition of peritoneal B cell populations and reduces secretory IgA levels. These findings suggest that S1P signalling may be a target to modulate B cell function in inflammatory intestinal pathologies.
Methods
S1P receptor expression was analysed in peritoneal B cells by real-time polymerase chain reaction (qPCR). The chemotactic response to S1P was studied in vitro. The role of S1P signalling was further explored in a s1p&sub4;-/- mouse strain.
Results
Peritoneal B cells expressed considerable amounts of the S1P receptors 1 and 4 (S1P&sub1; and S1P&sub4;, respectively). S1P&sub1; showed differential expression between the distinct peritoneal B cell lineages. While B2 cells showed no chemotactic response to S1P, B1 B cells showed a migration response to S1P. s1p&sub4;-/- mice displayed significant alterations in the composition of peritoneal B cell populations, as well as a significant reduction of mucosal immunoglobulin A (IgA) in the gut.