IgM and IgG but not cytokine secretion is restricted to the CD27+ B lymphocyte subset.
In a recent study we reported that CD27 is expressed on a subpopulation of human B lymphocytes and presented circumstantial phenotypic evidence that CD27 expression may be acquired late during B cell differentiation. Here we present functional data showing that, after in vitro stimulation, CD27+ but not CD27- B cells secrete large amounts of both IgM and IgG. Using double immunofluorescence staining of CD27 and IgD, three functionally different B cell subsets representing distinct stages of B cell differentiation can be isolated: 1) the CD27- IgD+ B cells, which do not secrete appreciable Ig; 2) the CD27+IgD+ B cells, which exclusively secrete IgM; and 3) the CD27+IgD- B cells, which comprise the IgG-producing cells. Furthermore, costimulation of CD27- B cells with low m.w. B cell growth factor, in the presence or in the absence of a CD40 mAb, does not induce these cells to become Ig-secreting cells. Although CD27- B cells hardly secrete Ig of any isotype in response to Staphylococcus aureus+IL-2, these cells proliferate vigorously and express the IL-2R alpha chain (CD25) under these stimulatory conditions. Furthermore, both CD27- and CD27+ B cells are capable of producing similar amounts of IL-6 and TNF-alpha. Taken together, these findings indicate that CD27 is a unique non-Ig surface marker discriminating naive from primed B lymphocytes. Furthermore, the capacity to proliferate and to secrete the B cell differentiation factors IL-6 and TNF-alpha already exists at an early B cell differentiation stage at which the cells lack CD27 expression and are not induced to produce Ig.
Maurer
D
D
Institute of Immunology, University of Vienna, Austria.
Fischer
G F
GF
Fae
I
I
Majdic
O
O
Stuhlmeier
K
K
Von Jeney
N
N
Holter
W
W
Knapp
W
W
D015703:Antigens, CD / Q000032:analysis*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis*; D016175:B-Lymphocyte Subsets / Q000276:immunology*; D016207:Cytokines / Q000378:metabolism*; D006801:Humans; D007072:Immunoglobulin D / Q000378:metabolism; D007074:Immunoglobulin G / Q000378:metabolism*; D007075:Immunoglobulin M / Q000378:metabolism*; D066298:In Vitro Techniques; D015850:Interleukin-6 / Q000378:metabolism; D008213:Lymphocyte Activation; D011947:Receptors, Antigen, B-Cell / Q000378:metabolism; D015375:Receptors, Interleukin-2 / Q000378:metabolism; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D016207:Cytokines; D007072:Immunoglobulin D; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D015850:Interleukin-6; D011947:Receptors, Antigen, B-Cell; D015375:Receptors, Interleukin-2; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7; D014409:Tumor Necrosis Factor-alpha