Human intestinal B-cell blasts and plasma cells express the mucosal homing receptor integrin alpha 4 beta 7.
Interactions between homing receptors on circulating leucocytes and endothelial addressins regulate tissue-specific cellular extravasation. Although integrin alpha 4 beta 7 appears to be the main receptor for gut-homing T lymphocytes, less is known about molecules mediating mucosal B cell homing. Expression of integrin alpha 4 beta 7 on B lymphocytes, B cell blasts, and plasma cells in human gut-associated lymphoid tissue (GALT; the Peyer's patches and appendix) and lamina propria was studied by multi-colour immunofluorescence applied on cryosections. Isolated mononuclear cells from the same tissue compartments were examined by flow cytometry and compared with peripheral blood B cells. Integrin alpha 4 beta 7 was expressed by IgA+ B cell blasts and plasma cells (CD38high) in the lamina propria, B cell blasts in GALT, and sIgD+ B lymphocytes in peripheral blood. In contrast, GALT sIgD+ B lymphocytes were negative or only weakly positive for alpha 4 beta 7. These results suggested that B lymphocytes down-regulate alpha 4 beta 7 upon extravasation in GALT but up-regulate this integrin after antigen-priming. Thus, alpha 4 beta 7 may be a homing receptor also for B cell blasts extravasating in the gut lamina propria, where this integrin is maintained on plasma cells, perhaps as a local retention factor.
Farstad
I N
IN
Laboratory for Immunohistochemistry and Immunopathology (LIIPAT), University of Oslo, Rikshospitalet, Norway.
Halstensen
T S
TS
Lazarovits
A I
AI
Norstein
J
J
Fausa
O
O
Brandtzaeg
P
P
D036541:ADP-ribosyl Cyclase; D051997:ADP-ribosyl Cyclase 1; D000328:Adult; D000368:Aged; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000096:biosynthesis; D016175:B-Lymphocyte Subsets / Q000276:immunology; D001402:B-Lymphocytes / Q000166:cytology / Q000378:metabolism*; D002454:Cell Differentiation; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006801:Humans; D007082:Ileum / Q000276:immunology; D007070:Immunoglobulin A / Q000096:biosynthesis; D016023:Integrins / Q000096:biosynthesis*; D007413:Intestinal Mucosa / Q000276:immunology*; D007583:Jejunum / Q000276:immunology; D008562:Membrane Glycoproteins; D009699:N-Glycosyl Hydrolases / Q000096:biosynthesis; D010950:Plasma Cells / Q000378:metabolism*; D016201:Receptors, Lymphocyte Homing / Q000096:biosynthesis*
D015703:Antigens, CD; D000943:Antigens, Differentiation; D007070:Immunoglobulin A; D016023:Integrins; D008562:Membrane Glycoproteins; D016201:Receptors, Lymphocyte Homing; C071777:integrin alpha4beta7; D009699:N-Glycosyl Hydrolases; D036541:ADP-ribosyl Cyclase; C498154:CD38 protein, human; D051997:ADP-ribosyl Cyclase 1