PMID-sentid Pub_year Sent_text comp_official_name comp_offsetprotein_name organism prot_offset 7680616-9 1993 The ability of anti-IgM to mobilize intracellular calcium was reduced in sIgM down-regulated cells, suggesting that B cells activation through the antigen receptor may be negatively regulated by CD20 and positively by IL-4. Calcium 50-57 keratin 20 Homo sapiens 195-199