{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,5]],"date-time":"2026-10-05T09:30:35Z","timestamp":1791192635747,"version":"4.1.0"},"reference-count":49,"publisher":"Oxford University Press (OUP)","issue":"7","license":[{"start":{"date-parts":[[2010,4,1]],"date-time":"2010-04-01T00:00:00Z","timestamp":1270080000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/academic.oup.com\/pages\/standard-publication-reuse-rights"}],"funder":[{"name":"Swedish Research Council, the Swedish Cancer Foundation, Sahlgrenska University Hospital LUA\/ALF grants, European Union","award":["QLK2-CT-2001-01702"],"award-info":[{"award-number":["QLK2-CT-2001-01702"]}]},{"name":"Swedish Research Council, the Swedish Cancer Foundation, Sahlgrenska University Hospital LUA\/ALF grants, European Union","award":["LSHP-CT-2003-503240"],"award-info":[{"award-number":["LSHP-CT-2003-503240"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2010,4,1]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Recently, we reported that CD40\u2212\/\u2212 mice, exhibiting exclusively T cell-independent IgA class switch recombination (CSR), demonstrated near normal levels of IgA plasma cells in the gut lamina propria (LP), despite the complete lack of germinal centers (GCs). In this study, we have extended our analysis focusing on how to reconcile these findings using flow cytometry and molecular markers for IgA CSR. In agreement with our previous results with small intestinal LP, the colon LP was found to host IgA CSR only when lymphoid follicles were present. Thus, no IgA CSR was observed in the nonorganized colon LP. By contrast, the Peyer\u2019s patch (PP) was the dominant IgA CSR site in both CD40\u2212\/\u2212 and wild type (WT) mice, and they both hosted similar levels of mRNA expression for B cell activating factor of the TNF family, a proliferation inducing ligand, and inducible NO synthase, potential switch-factors for IgA. Unexpectedly, we found that PP B cells undergoing IgA CSR were GL7-intermediate. These cells had not undergone somatic hypermutations (SHMs), whereas GL7-high cells in WT PP, which exhibited GCs, were heavily mutated. Moreover, IgA plasma cells in the LP of CD40\u2212\/\u2212 mice demonstrated few mutations in their Ig V regions, whereas WT LP B cells from different sites showed extensive SHMs, which were also clonally related. Therefore, IgA CSR can occur in PP at a stage preceding manifest GC (GL7-intermediate), whereas SHM require GC formations (GL7-high). These findings reconcile that IgA CSR can occur in PP in the absence of GC with the fact that CD40\u2212\/\u2212 mice host near normal levels of IgA plasma cells in the LP.<\/jats:p>","DOI":"10.4049\/jimmunol.0901895","type":"journal-article","created":{"date-parts":[[2010,3,5]],"date-time":"2010-03-05T22:29:03Z","timestamp":1267828143000},"page":"3545-3553","source":"Crossref","is-referenced-by-count":121,"title":["T Cell-Independent IgA Class Switch Recombination Is Restricted to the GALT and Occurs Prior to Manifest Germinal Center Formation"],"prefix":"10.1093","volume":"184","author":[{"given":"Peter","family":"Bergqvist","sequence":"first","affiliation":[{"name":"Department of Microbiology and Immunology, Mucosal Immunobiology and Vaccine Center, Institute of Biomedicine, University of Gothenburg , Gothenburg,","place":["Sweden"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anneli","family":"Stensson","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Immunology, Mucosal Immunobiology and Vaccine Center, Institute of Biomedicine, University of Gothenburg , Gothenburg,","place":["Sweden"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nils Y","family":"Lycke","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Immunology, Mucosal Immunobiology and Vaccine Center, Institute of Biomedicine, University of Gothenburg , Gothenburg,","place":["Sweden"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mats","family":"Bemark","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Immunology, Mucosal Immunobiology and Vaccine Center, Institute of Biomedicine, University of Gothenburg , Gothenburg,","place":["Sweden"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"286","published-online":{"date-parts":[[2010,4,1]]},"reference":[{"key":"2026012806353353600_r1","doi-asserted-by":"crossref","first-page":"583","DOI":"10.1016\/B978-012491543-5\/50035-8","article-title":"IgA B cell development.","volume-title":"Mucosal immunology","author":"Strober","year":"2005","edition":"3rd Ed"},{"key":"2026012806353353600_r2","doi-asserted-by":"crossref","first-page":"261","DOI":"10.1146\/annurev.immunol.26.021607.090248","article-title":"Mechanism and regulation of class switch recombination.","volume":"26","author":"Stavnezer","year":"2008","journal-title":"Annu. 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