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CD5 regulates B‐1a B‐cell expansion and selection
Author(s) -
Sestero Christine M.,
Singh Simer Preet,
Axtell Robert,
Raman Chander
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.847.4
Subject(s) - cd5 , b cell , phenotype , biology , microbiology and biotechnology , population , antibody , immunology , medicine , genetics , gene , environmental health
The expression of CD5 is the defining phenotypic characteristic of the B‐1a population of B‐cells. However, the role of CD5 in the development and physiology of B‐ 1a B cells has remained controversial. Our laboratory recently discovered that a major role of CD5 is to regulate survival in activated T‐cells and this activity was mediated by the unique interaction of CD5 with CK2. To determine if this biological activity of CD5 extended to B‐1a B‐cells, we developed a CD5 knock‐in mouse (CD5ΔCK2BD) in which the ability of CD5 to bind and activate CK2 was abrogated. The absolute number of B‐1a B‐cells in the peritoneum and natural IgM in the serum of the CD5ΔCK2BD mouse was dramatically lower than that in the CD5 WT mouse. Furthermore, we observed selective reduction of VH11Vê9 anti‐PtC B‐cells in the CD5ΔCK2BD mouse, suggesting altered positive selection. The contraction of B‐1a B‐cells in the CD5CK2BD mouse was in part due to arrest of cells from entering into cell cycle. Interestingly, costimulation with TLR 4/9 agonists and IFN‐β led to levels of IL‐10 production from CD5ΔCK2BD B‐1 B cells that was absent if B‐1 B‐cells were obtained from CD5 WT or CD5−/− mice. Our findings represent the first in vivo evidence that CD5 contributes to the development and biology of B‐1a cells in mice. Supported by the NMSS and NIH.