IgM‐ and IgD‐bearing peripheral blood lymphocytes differentiate to IgM but not IgG or IgA immunoglobulin‐secreting cells

Abstract

Human peripheral blood mononuclear cells were depleted of surface IgM+ or IgD+ cells and assayed for mitogen-induced differentiation to immunoglobulin-secreting cells (ISC) of IgM, IgG and IgA classes. Stimulatory agents included T cell-dependent pokeweed mitogen, B cell mitogen Staphylococcus aureus bacteria strain Cowan I, and a combination of the two which gives uniform, high levels of ISC from all normal donors. Depletion of either IgM- or IgD-bearing B lymphocytes resulted in loss of cells bearing the other Ig class and blocked most of the mitogenic reactivity to anti-IgM and anti-IgD. Proliferative responses to Cowan I in these depleted populations were about 20% that of unfractionated mononuclear cells. Depletion of T cells increased the mitogenic response to Cowan I and to the two antibody preparations, showing that they are T-independent mitogens. Depletion of IgD+ cells caused partial loss of mitogen-induced IgM ISC (22%-60% of unseparated controls) but no loss of IgG or IgA ISC. Depletion of IgM-bearing cells caused complete loss of IgM ISC, but no loss of IgG or IgA ISC. We previously demonstrated that anti-IgM ISC, but no loss of IgG or IgA ISC. We previously demonstrated that anti-IgM antibody blocked mitogen induction of Ig secretion of these three classes in spleen cells, but only IgM secretion in blood mononuclear cells. Together, the results suggest that the majority of cells in normal blood responding to mitogens to mature to IgG or IgA production belong to IgM-, IgD- B cell subjects, in contrast to precursors of secreting cells for these isotypes in the spleen. Thus, these blood precursors appear to be more mature than the corresponding spleen cells.

Inhibition of N-linked oligosaccharide trimming mannosidases blocks human B cell development.

“…As non-Ig controls, we routinely analyzed HLA-A,B antigens to afford a diagnosis of N-linked glycan type in cultures where Ig synthesis was strongly inhibited. It should be emphasized that addition of inhibitor is required at a timepoint preceding significant Ig synthesis, which is on day 3 or later, in PWM -SAC stimulated cultures (Saiki and Ralph, 1981;Scholten et al, 1986). We conclude that in the presence of SW, terminal modifications can take place, resulting in the addition of a single sialic acid per N-linked glycan and acquisition of EndoH resistance.…”

“…The synergy between PWM and SAC has been interpreted as evidence in favour of a two-signal model for B cell activation (Saiki and Ralph, 1981;Falkoff et al, 1982). For most donors, the combination of PWM and SAC acts synergistically.…”

The kinetics and phenotype of the human B‐cell response following immunization with a heptavalent pneumococcal‐CRM197 conjugate vaccine

“…Analysis of B‐cell division by flow cytometry and carboxy‐fluorescein diacetate, succinimidyl ester (CFSE) labelling has shown that five days of in‐vitro stimulation is long enough for the cells to undergo at least four division cycles and that this number of division cycles is necessary for antibody secretion 19 . This system preferentially activates memory B cells, 26,27 and induces IgM memory B cells (CD27 + IgM + IgD + ) to secrete IgM and IgG, while class switched memory B cells (CD27 + IgM – IgD – ) will secrete IgG and IgA 28 . The SAC + IL‐2 system probably induces a mixture of pre‐existing memory B cells and newly generated precursor plasma cells to secrete antibody.…”

Severe deficiency of switched memory B cells (CD27+IgM−IgD−) in subgroups of patients with common variable immunodeficiency: a new approach to classify a heterogeneous disease

“…They, however, failed also to produce significant levels of IgG, confirming the previous finding that SAC plus IL-2 is not sufficient to induce class switch in vitro. 15 The data presented in Table 2 also explain why in cultures of PBLs stimulated with SAC plus IL-2 it is impossible to correlate IgM production in vitro to the IgM memory B-cell pool: In the presence of CD4 ϩ T cells, both CD27 Ϫ IgM ϩ naive B cells and CD27 ϩ IgM ϩ memory B cells are induced to IgM production.…”