A unique B2 B cell subset in the intestine.
Over 80% of the body's activated B cells are located in mucosal sites, including the intestine. The intestine contains IgM(+) B cells, but these cells have not been characterized phenotypically or in terms of their developmental origins. We describe a previously unidentified and unique subset of immunoglobulin M(+) B cells that present with an AA4.1(-)CD21(-)CD23(-) major histocompatibility complex class II(bright) surface phenotype and are characterized by a low frequency of somatic hypermutation and the potential ability to produce interleukin-12p70. This B cell subset resides within the normal mucosa of the large intestine and expands in response to inflammation. Some of these intestinal B cells originate from the AA4.1(+) immature B2 cell pool in the steady state and are also recruited from the recirculating naive B cell pool in the context of intestinal inflammation. They develop in an antigen-independent and BAFF-dependent manner in the absence of T cell help. Expansion of these cells can be induced in the absence of the spleen and gut-associated lymphoid tissues. These results describe the existence of an alternative pathway of B cell maturation in the periphery that gives rise to a tissue-specific B cell subset.
Experimental Pathology Unit, Massachusetts General Hospital, Boston, MA 02114, USA.
Yasuyo
Y
Shimomura
Atsuhiro
A
Ogawa
Mayumi
M
Kawada
Ken
K
Sugimoto
Emiko
E
Mizoguchi
Hai-Ning
HN
Shi
Shiv
S
Pillai
Atul K
AK
Bhan
Atsushi
A
Mizoguchi
D048868:Adaptor Proteins, Signal Transducing / Q000032:analysis*; D000818:Animals; D000906:Antibodies / Q000276:immunology; D000071183:Autophagy-Related Proteins; D016175:B-Lymphocyte Subsets / Q000276:immunology*; D006681:HLA-D Antigens / Q000276:immunology; D006801:Humans; D018928:Immunity, Mucosal; D007075:Immunoglobulin M / Q000276:immunology*; D016130:Immunophenotyping; D007249:Inflammation / Q000276:immunology; D007413:Intestinal Mucosa / Q000276:immunology*; D007420:Intestine, Large / Q000276:immunology*; D008562:Membrane Glycoproteins / Q000032:analysis*; D051379:Mice; D017464:Receptors, Complement 3d / Q000172:deficiency*; D017455:Receptors, IgE / Q000172:deficiency*
D048868:Adaptor Proteins, Signal Transducing; D000906:Antibodies; D000071183:Autophagy-Related Proteins; D006681:HLA-D Antigens; D007075:Immunoglobulin M; D008562:Membrane Glycoproteins; C476215:PLEKHM1 protein, human; D017464:Receptors, Complement 3d; D017455:Receptors, IgE