Single cell analysis of adenoid CD5+ B cells and their protective contributions to nasopharyngeal immunity.
OBJECTIVE
CD5+ B cells are phenotypically and functionally distinct from the conventional (CD5-) B cells, and the function of CD5+ B cells in the upper respiratory tract remains unknown. A previous study showed that immunoglobulin A-producing cells in the adenoid play a protective role in the nasopharynx. In the present study, the contribution of adenoid CD5+ B cells to nasopharyngeal immunity at the single cell level was investigated.


METHODS
In vitro laboratory study.


METHODS
Mononuclear cells were isolated from adenoids of children aged 1 to 12 years, and the frequency of CD5+ B cells was determined by flow cytometry. The numbers of cells producing immunoglobulin M, immunoglobulin G, and immunoglobulin A in sorted adenoid CD5+ B cells were determined by enzyme-linked immunospot assay. Further, to characterize adenoid CD5+ B cells, the expression of various surface molecules was analyzed by flow cytometry.


RESULTS
The results showed that adenoids of young children contain a relatively large number of CD5+ B cells, which have a greater capacity for antibody production than do CD5- B cells. CD5+ B cells also differed from CD5- B cells in the expression of interleukin receptors Il-4R, IL-5R, and IL-10R as well as CD27, B7-1, B7-2, Fas, and Bcl-2.


CONCLUSIONS
These findings suggest that adenoid CD5+ B cells contribute to protective immunity by forming a first line of defense in the upper respiratory tract of young children and that they are probably regulated in a manner that differs from that of CD5- B cells.
Arita
Miori
M
Department of Otolaryngology, Oita Medical University, Hazama-machi, Oita 879-5593, Japan.
Kodama
Satoru
S
Suzuki
Masashi
M
Mogi
Goro
G
D000233:Adenoidectomy; D000234:Adenoids / Q000276:immunology* / Q000473:pathology / Q000601:surgery; D000907:Antibodies, Bacterial / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology*; D018956:CD5 Antigens / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D046508:Culture Techniques; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D006984:Hypertrophy / Q000473:pathology; D007070:Immunoglobulin A / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D007075:Immunoglobulin M / Q000276:immunology; D007223:Infant; D008297:Male; D009305:Nasopharynx / Q000276:immunology* / Q000473:pathology; D018123:Receptors, Interleukin / Q000276:immunology; D012141:Respiratory Tract Infections / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology
D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D018956:CD5 Antigens; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D018123:Receptors, Interleukin