Zhai SK, Volgina VV, Sethupathi P, Knight KL, Lanning DK. Chemokine-mediated B cell trafficking during early rabbit GALT development.
THE JOURNAL OF IMMUNOLOGY 2014;
193:5951-9. [PMID:
25385821 DOI:
10.4049/jimmunol.1302575]
[Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Microbial and host cell interactions stimulate rabbit B cells to diversify the primary Ab repertoire in GALT. B cells at the base of appendix follicles begin proliferating and diversifying their V-(D)-J genes around 1 wk of age, ∼5 d after B cells first begin entering appendix follicles. To gain insight into the microbial and host cell interactions that stimulate B cells to diversify the primary Ab repertoire, we analyzed B cell trafficking within follicles during the first week of life. We visualized B cells, as well as chemokines that mediate B cell homing in lymphoid tissues, by in situ hybridization, and we examined B cell chemokine receptor expression by flow cytometry. We found that B cells were activated and began downregulating their BCRs well before a detectable B cell proliferative region appeared at the follicle base. The proliferative region was similar to germinal center dark zones, in that it exhibited elevated CXCL12 mRNA expression, and B cells that upregulated CXCR4 mRNA in response to signals acquired from selected intestinal commensals localized in this region. Our results suggest that after entering appendix follicles, B cells home sequentially to the follicle-associated epithelium, the follicular dendritic cell network, the B cell/T cell boundary, and, ultimately, the base of the follicle, where they enter a proliferative program and diversify the primary Ab repertoire.
Collapse