Leucine-rich repeat kinase 2 is a regulator of B cell function, affecting homeostasis, BCR signaling, IgA production, and TI antigen responses

LRRK2 is the causal molecule of autosomal dominant familial Parkinson's disease. B2 cells express a much higher LRRK2 mRNA level than B1 cells. To reveal the function of LRRK2 in B cells, we analyzed B cell functions in LRRK2-knockout (LRRK2−/−) mice. LRRK2−/− mice had significantly higher counts of peritoneal B1 cells than wild-type mice. After BCR stimulation, phosphor-Erk1/2 of splenic B2 cells was enhanced to a higher degree in LRRK2−/− mice. LRRK2−/− mice had a significantly higher serum IgA level, and TNP–Ficoll immunization increased the titer of serum anti-TNP IgM antibody. LRRK2 may play important roles in B cells.