Expression of CD2 on porcine B lymphocytes.
Remarkable interspecies differences in CD2 expression on B lymphocytes have been reported in mammals. Human and rat B cells lack CD2, whilst B lymphocytes in mice are CD2+. In pigs, B cells have been supposed not to express CD2. We show here, however, that CD2 is present at a low level on a prominent subset of porcine B cells. Moreover, we describe changes in the proportions of CD2+ and CD2- B-cell subsets during ontogeny. Before contact with microflora, the majority of peripheral surface immunoglobulin M+ (sIgM+) B cells express CD2 and sIgM+CD2- B cells are rare. Shortly after colonization of conventional (CV) piglets with complex intestinal microflora, numerous CD2- B cells appear in the periphery and their relative number increases with age in both CV and specific pathogen-free (SPF) pigs. However, monoassociation of germ-free (GF) piglets with a single Escherichia coli strain does not result in a significant increase of sIgM+CD2- B cells in the periphery. We suggest that CD2 is down-regulated in porcine B lymphocytes upon activation with microflora in mucosa-associated lymphatic tissues. In bone marrow (BM), we identified putative porcine B-cell precursors. These cells express CD2 at low density and do not bear either the common myelomonocytic antigen or T and B-lymphocyte receptors. Similar to mouse and human pre-B cells, this lymphocyte-sized subset expresses CD25 and class II antigens. CD2 positivity of these cells indicates that CD2 is expressed earlier than sIgM during B lymphopoiesis in pigs.
Sinkora
J
J
Department of Immunology and Gnotobiology, Institute of Microbiology, Academy of Sciences of the Czech Republic, Novy Hradek.
Reháková
Z
Z
Sinkora
M
M
Cukrowska
B
B
Tlaskalová-Hogenová
H
H
Bianchi
A T
AT
De Geus
B
B
D000375:Aging / Q000276:immunology; D000818:Animals; D000943:Antigens, Differentiation / Q000378:metabolism; D016175:B-Lymphocyte Subsets / Q000276:immunology*; D001853:Bone Marrow / Q000276:immunology; D018801:CD2 Antigens / Q000378:metabolism*; D002454:Cell Differentiation / Q000276:immunology; D004927:Escherichia coli Infections / Q000276:immunology; D005260:Female; D005434:Flow Cytometry; D005856:Germ-Free Life; D016130:Immunophenotyping; D007422:Intestines / Q000382:microbiology; D007963:Leukocytes, Mononuclear / Q000276:immunology; D013552:Swine / Q000276:immunology*
D000943:Antigens, Differentiation; D018801:CD2 Antigens