AUTHOR=Cancro Michael P., Scholz Jean L., Sindhava Vishal J. TITLE=Roles for BLyS family members in meeting the distinct homeostatic demands of innate and adaptive B cells JOURNAL=Frontiers in Immunology VOLUME=Volume 4 - 2013 YEAR=2013 URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2013.00037 DOI=10.3389/fimmu.2013.00037 ISSN=1664-3224 ABSTRACT=B-1 and B-2 B cell populations have different progenitors, receptor diversity, anatomic location, and functions -- suggesting vastly difffering requisites for homeostatic regulation. There is evidence that the BLyS family of cytokines and receptors, key factors in the homeostatic regulation of B-2 B cell subsets, is also a major player in the B-1 compartment. Here we review the development and differentiation of these two primary B cell lineages and their immune functions. We discuss evidence that BLyS or APRIL availability in different anatomic sites, coupled with signature BLyS receptor expression patterns on different B cell subsets, may be important for homeostatic regulation of B-1 as well as B-2 populations. Finally, we extend our working model of B cell homeostasis to integrate B-1s.