Twohig J, Kulik L, Haluszczak C, Reuter J, Rossbach A, Bull M, Holers VM, Marchbank KJ. Defective B cell ontogeny and immune response in human complement receptor 2 (CR2, CD21) transgenic mice is partially recovered in the absence of C3.
Mol Immunol 2007;
44:3434-44. [PMID:
17379312 PMCID:
PMC1948027 DOI:
10.1016/j.molimm.2007.02.011]
[Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2007] [Revised: 02/12/2007] [Accepted: 02/14/2007] [Indexed: 01/13/2023]
Abstract
Mice prematurely expressing human CR2 (hCR2) in the B cell lineage have a defective B cell ontogeny and immune response. Our recent analysis of this phenotype suggested that signaling through hCR2 and presumably mouse CD19 on the B cell surface, during bone marrow development, could result in the observed changes in B cell function in these mice. To test this hypothesis, we back crossed hCR2(high) transgenic mice onto the CD19(-/-) background. CD19(-/-)hCR2(high) mice were found to possess even fewer mature B cells than their CD19(+/+)hCR2(high) littermates, demonstrating that loss of CD19 exacerbated the effects elicited through hCR2. This data suggests that CD19 provides a survival signal during B cell development in this model. Next, we examined if the removal of the main ligand for CR2, namely C3d, through back-crossing onto the C3(-/-) background could restore normal B cell development. However, we found only minor recovery in peripheral B cell numbers and no obvious change in function. This was despite a three-fold increase in the level of hCR2 expression on B cells isolated from the spleen or bone marrow of C3(-/-)hCR2(high) mice when compared with C3 sufficient littermates. These data demonstrate that hCR2 is integrated in mouse B cell signaling and that the downstream effects of hCR2 expression during early B cell development are partially but not completely due to interaction with C3 fragments and signaling through CD19 in the bone marrow environment.
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