A Reassessment of IgM Memory Subsets in Humans.
From paired blood and spleen samples from three adult donors, we performed high-throughput VH sequencing of human B cell subsets defined by IgD and CD27 expression: IgD(+)CD27(+) ("marginal zone [MZ]"), IgD(-)CD27(+) ("memory," including IgM ["IgM-only"], IgG and IgA) and IgD(-)CD27(-) cells ("double-negative," including IgM, IgG, and IgA). A total of 91,294 unique sequences clustered in 42,670 clones, revealing major clonal expansions in each of these subsets. Among these clones, we further analyzed those shared sequences from different subsets or tissues for VH gene mutation, H-CDR3-length, and VH/JH usage, comparing these different characteristics with all sequences from their subset of origin for which these parameters constitute a distinct signature. The IgM-only repertoire profile differed notably from that of MZ B cells by a higher mutation frequency and lower VH4 and higher JH6 gene usage. Strikingly, IgM sequences from clones shared between the MZ and the memory IgG/IgA compartments showed a mutation and repertoire profile of IgM-only and not of MZ B cells. Similarly, all IgM clonal relationships (among MZ, IgM-only, and double-negative compartments) involved sequences with the characteristics of IgM-only B cells. Finally, clonal relationships between tissues suggested distinct recirculation characteristics between MZ and switched B cells. The "IgM-only" subset (including cells with its repertoire signature but higher IgD or lower CD27 expression levels) thus appear as the only subset showing precursor-product relationships with CD27(+) switched memory B cells, indicating that they represent germinal center-derived IgM memory B cells and that IgM memory and MZ B cells constitute two distinct entities.
Institut Necker-Enfants Malades, INSERM U1151-Centre National de la Recherche Scientifique Unité Mixte de Recherche 8253, Université Paris Descartes, Faculté de Médecine-Site Broussais, 75993 Paris Cedex 14, France;
Davide
D
Bagnara
Dipartimento di Informatica, Bioingegneria, Robotica e Ingegneria dei Sistemi, Università degli Studi di Genova, 16146 Genoa, Italy;
Margherita
M
Squillario
Institute of Cancer and Genetics, School of Medicine, Cardiff University, Cardiff CF14 4XN, United Kingdom;
David
D
Kipling
Laboratoire de Physique Statistique, Centre National de la Recherche Scientifique Unité Mixte de Recherche 8550, Université Pierre et Marie Curie and Ecole Normale Supérieure, 75005 Paris, France;
Thierry
T
Mora
Laboratoire de Physique Théorique, Unité Mixte de Recherche 8549, Centre National de la Recherche Scientifique and Ecole Normale Supérieure, 75005 Paris, France; and.
Aleksandra M
AM
Walczak
Institut Necker-Enfants Malades, INSERM U1151-Centre National de la Recherche Scientifique Unité Mixte de Recherche 8253, Université Paris Descartes, Faculté de Médecine-Site Broussais, 75993 Paris Cedex 14, France;
Lucie
L
Da Silva
Institut Necker-Enfants Malades, INSERM U1151-Centre National de la Recherche Scientifique Unité Mixte de Recherche 8253, Université Paris Descartes, Faculté de Médecine-Site Broussais, 75993 Paris Cedex 14, France;
Sandra
S
Weller
Department of Immunobiology, Faculty of Life Sciences and Medicine, King's College London, London SE1 9RT, United Kingdom.
Deborah K
DK
Dunn-Walters
Institut Necker-Enfants Malades, INSERM U1151-Centre National de la Recherche Scientifique Unité Mixte de Recherche 8253, Université Paris Descartes, Faculté de Médecine-Site Broussais, 75993 Paris Cedex 14, France; jean-claude.weill@inserm.fr claude-agnes.reynaud@inserm.fr.
Jean-Claude
JC
Weill
Institut Necker-Enfants Malades, INSERM U1151-Centre National de la Recherche Scientifique Unité Mixte de Recherche 8253, Université Paris Descartes, Faculté de Médecine-Site Broussais, 75993 Paris Cedex 14, France; jean-claude.weill@inserm.fr claude-agnes.reynaud@inserm.fr.
Claude-Agnès
CA
Reynaud
D000328:Adult; D001402:B-Lymphocytes / Q000276:immunology*; D022801:Complementarity Determining Regions / Q000235:genetics* / Q000276:immunology; D005260:Female; D006801:Humans; D007072:Immunoglobulin D / Q000235:genetics / Q000276:immunology; D007143:Immunoglobulin Heavy Chains / Q000235:genetics* / Q000276:immunology; D007075:Immunoglobulin M / Q000235:genetics* / Q000276:immunology; D007156:Immunologic Memory; D008297:Male; D008875:Middle Aged; D009154:Mutation
D022801:Complementarity Determining Regions; D007072:Immunoglobulin D; D007143:Immunoglobulin Heavy Chains; D007075:Immunoglobulin M