A novel pathway of human B cell activation initiated by CK226 surface antigen.
In this study we analyzed the effect of CK226 monoclonal antibody (mAb) on human B cell activation and proliferation. This mAb was shown to recognize a 75-kDa surface molecule expressed on both T and B lymphocytes and to mediate T lymphocyte activation and proliferation. Flow cytometry analysis of B cell populations isolated from peripheral blood, tonsil and spleen showed that CK226 surface antigen is highly expressed on 40-80% of surface Ig+ cells. When purified B cells were cultured in the presence of CK226 mAb, up-regulation of major histocompatibility complex class II and CD23 surface structures and the de novo expression of CD25 antigen could be detected within 48 h. In addition, B cells underwent proliferation ([3H] thymidine uptake) in the absence of either T cells or exogenous lymphokines. Proliferation was potentiated by the addition of suboptimal concentrations (0.5 ng/ml) of phorbol 12-myristate 13-acetate (PMA). Cells recovered at day 5 were surface Ig+ and no CD3+ cells could be detected. CK226-induced proliferation (either in the presence or in the absence of PMA) was not inhibited by anti-CD25 mAb. Addition of exogenous interleukin 2 to CK226-stimulated B cells resulted in further increase of B cell proliferation. On the other hand, CK226 mAb did not display a co-stimulatory effect with submitogenic concentrations of either anti-Ig antibody or Staphylococcus aureus Cowan strain I bacteria. In addition proliferation induced by mitogenic concentrations of the above stimuli was inhibited in a dose-dependent fashion by CK226 mAb.
Poggi
A
A
Istituto Nazionale per la Ricerca sul Cancro, University of Genoa, Italy.
Maggi
E
E
Biagiotti
R
R
Giudizi
M G
MG
Almerigogna
F
F
Pella
N
N
Caligaris-Cappio
F
F
Romagnani
S
S
Moretta
L
L
D000888:Antibodies, Anti-Idiotypic / Q000276:immunology; D000911:Antibodies, Monoclonal; D015703:Antigens, CD / Q000096:biosynthesis; D000944:Antigens, Differentiation, B-Lymphocyte / Q000096:biosynthesis; D000954:Antigens, Surface / Q000502:physiology*; D001402:B-Lymphocytes / Q000276:immunology*; D005786:Gene Expression Regulation / Q000276:immunology; D006681:HLA-D Antigens / Q000096:biosynthesis; D006801:Humans; D007075:Immunoglobulin M / Q000276:immunology; D007376:Interleukin-2 / Q000502:physiology; D008213:Lymphocyte Activation / Q000276:immunology; D014066:Palatine Tonsil / Q000166:cytology; D011961:Receptors, Fc / Q000096:biosynthesis; D017455:Receptors, IgE; D015375:Receptors, Interleukin-2 / Q000096:biosynthesis; D013154:Spleen / Q000166:cytology; D013211:Staphylococcus aureus / Q000276:immunology; D015854:Up-Regulation / Q000276:immunology
D000888:Antibodies, Anti-Idiotypic; D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000944:Antigens, Differentiation, B-Lymphocyte; D000954:Antigens, Surface; D006681:HLA-D Antigens; D007075:Immunoglobulin M; D007376:Interleukin-2; D011961:Receptors, Fc; D017455:Receptors, IgE; D015375:Receptors, Interleukin-2