Title

Naive B lymphocytes undergo homeostatic proliferation in response to B cell deficit

GSBS Program

Biochemistry & Molecular Pharmacology

UMMS Affiliation

Graduate School of Biomedical Sciences; Department of Molecular Genetics and Microbiology; Department of Physiology

Date

12-10-2002

Document Type

Article

Medical Subject Headings

Adoptive Transfer; Animals; B-Lymphocyte Subsets; Cell Differentiation; Cell Division; Feedback; Female; Homeostasis; Immunophenotyping; Interleukin-17; Interphase; Lymphopenia; Male; Mice; Mice, Inbred A; Mice, Inbred C57BL; Mice, Inbred CBA; Mice, Knockout; Mice, SCID; Mice, Transgenic; NF-kappa B; NF-kappa B p50 Subunit; Protein-Tyrosine Kinases; Proto-Oncogene Proteins c-rel; Signal Transduction; Spleen

Disciplines

Life Sciences | Medicine and Health Sciences

Abstract

Naive peripheral B cells are maintained in sufficient numbers and diversity to mount effective immune responses against infectious agents. However, the size and repertoire of this B cell pool is constantly diminished by normal cell turnover and Ag activation. Homeostatic (Ag-independent) proliferation in response to B cell depletion is one mechanism to compensate for this cell loss. We have used purified CFSE-labeled B cells and an adoptive transfer model system to show that immature and mature B cells divide in a variety of B cell-deficient (scid, xid, IL-7(-/-), and sublethally irradiated) hosts. Homeostatic B cell proliferation is T cell independent, and B cells that have replicated by this mechanism retain the antigenic phenotype of naive B cells. Replication is significantly reduced in B cell-sufficient normal or B cell-reconstituted immunodeficient recipients by the action of competing mature follicular B cells. Using xid mice and transcription factor knockouts, we show that the activation signal(s) that lead to homeostatic B cell proliferation require Bruton's tyrosine kinase; however, c-Rel, a Bruton's tyrosine kinase-induced NF-kappaB/Rel transcription factor critical for Ag and mitogen stimulation, is dispensable, indicating the uniqueness of this activation pathway. Survival and replication signals can also be separated, because the transcription factor p50 (NF-kappaB1), which is required for the survival of peripheral B cells, is not necessary for homeostatic replication. Homeostatic B cell proliferation provides an Ag-independent mechanism for the maintenance and expansion of naive B cells selected into the mature B cell pool.

Rights and Permissions

Citation: J Immunol. 2002 Dec 15;169(12):6795-805.

Related Resources

Link to article in PubMed

PubMed ID

12471111