title: Role of IL-10 in the distribution of B cell subsets in the mouse B-1 cell population.
abstract: The B lymphocyte compartment is comprised of B-1 and B-2 cells. The former is divided into B-1a, which express CD5, and B-1b cells which do not: both are self-renewing, although the mechanisms are yet to be identified. IL-10-/- mice were used to delineate the role of the B cell activator IL-10 in this process. Its absence had no effect on the total number of B-1 cells, but decreased that of B-1a cells (0.8 +/- 0.1 versus 1.7 +/- 0.2 x 10(6), p < 0.002), while increasing that of B-1b cells (1.9 +/- 0.4 versus 0.8 +/- 0.1 x 10(6), p < 0.03). The number of B-1a cells remained low in IL-10-injected IL-10-/- mice, whereas the excess of B-1b cells further increased (2.8 +/- 0.2 versus 1.6 +/- 0.4 x 10(6), p < 0.03). On the basis that Bax and Bad were augmented in B-1a cells, and Bcl-2 and Bcl-xL reduced, we conclude that the disappearance of B-1a cells, but not B-1b, in IL-10-/- mice results from their enhanced susceptibility to apoptosis. In addition, culture of IL-10-/- B-1a and B-1b cells in the presence of IL-10 drives more of the latter than of the former into cycle (p < 0.02). Therefore, IL-10 exerts two, complementary effects on the distribution of B-1 cell sub-populations, rescuing B-1a cells from apoptosis and encouraging B-1b cell proliferation.
authors.affiliation: Laboratory of Immunology, Brest University Medical School Hospital, BP 824, F 29609 Brest, France.
authors.forename: Jacques-Olivier
authors.initials: JO
authors.lastname: Pers
authors.forename: Christophe
authors.initials: C
authors.lastname: Jamin
authors.forename: Pierre
authors.initials: P
authors.lastname: Youinou
authors.forename: Jeannine
authors.initials: J
authors.lastname: Charreire
mesh_terms: D000818:Animals; D017209:Apoptosis; D016175:B-Lymphocyte Subsets / Q000502:physiology*; D001402:B-Lymphocytes / Q000166:cytology / Q000378:metabolism; D001483:Base Sequence; D017931:DNA Primers; D016753:Interleukin-10 / Q000008:administration & dosage / Q000235:genetics / Q000502:physiology*; D051379:Mice; D008808:Mice, Inbred CBA; D018345:Mice, Knockout; D012333:RNA, Messenger / Q000235:genetics; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D017931:DNA Primers; D012333:RNA, Messenger; D011994:Recombinant Proteins; D016753:Interleukin-10