Physiology of IgD. IV. Enhancement of antibody production in mice bearing IgD-secreting plasmacytomas.

Abstract

Immune responses to trinitrophenylated hemocyanin (TNP-KLH), Ficoll (TNP-Ficoll), and Brucella abortus (TNP-BA) were examined in BALB/c mice bearing subcutaneous transplants of TEPC-1017 and TEPC-1033, the two known IgD-secreting BALB/c plasmacytomas. Both primary and secondary 19S and 7S splenic plaque-forming cell (PFC) responses in spleen to intravenously injected TNP-KLH were enhanced three to fivefold. Primary responses to TNP-Ficoll were 1.5-2 times higher than in control mice (particularly the 7S PFC response). Primary responses to TNP-BA were enhanced by TEPC-1017 but suppressed by TEPC-1033, while secondary responses to TNP-BA were enhanced three to sevenfold by both tumors. Intraperitoneal injections of ascites fluid from mice bearing TEPC-1017 or TEPC-1033, or of IgD isolated from such ascites fluid, caused a similar enhancement of the primary response to TNP-KLH, as did the tumor itself, particularly when injected approximately 1 wk before antigen injection. IgD-containing ascites fluid had no effect on the response of athymic (nu/nu) BALB/c mice to TNP-KLH. These findings suggest the existence of an IgD-responsive immunoregulatory T cell.

Role of IgD and Tδ Cells in the Regulation of the Humoral Immune Response

“…I). This was in marked contrast to results with plasmacytomas secreting other isotypes (Zolla-Pazner et al 1974, Xue et al 1984. We hypothesized that the immunoaugmentation resulted from the elevated serum IgD levels in the IgD plasmacytoma-bearing mice.…”

“…As in the case of IgD plasmacytoma-bearing mice, the immunoaugmenting effect of IgD pre-treatment was seen both in primary and secondary responses. Comparable results were obtained with affinity purified IgD (Xue et al 1984). In similar experiments with athymic BALB/c mice, however, IgD had no effect on the response to either T-dependent or T-independent antigens, suggesting a crucial role for T cells in the IgD-induced immunoaugmentation.…”

“…Our interest in IgD has focused on the elucidation of a functional property of IgD myeloma proteins which we first observed in IgD plasmacytoma-bearing mice. BALB/c mice injected with such IgD-secreting tumors show significantly enhanced humoral immune responses (Xue et al 1984). This immunoaugmenting effect of IgD is in marked contrast to the immunosuppressive effects associated with plasmacytomas which secrete other isotypes (Zolla-Pazner et al 1974, Havas et al 1979.…”

IgD in Human Colostrum

“…All of these studies support the concept that IgD may act as a receptor and may regulate B cell differentiation. Recent work by Xue et al (28) demonstrated an enhanced 19s and 7s antibody response to keyhole limpet hemocyanin in mice bearing IgD-secreting plasmacytornas. The authors suggested the existence of an IgD responsive regulatory T cell.…”

IgD-receptor (IgD-R) cross-linking partially protects murine T cells from dexamethasone-induced apoptosis

“…Immunoglobulin D (IgD) is a major antigen receptor isotype coexpressed with IgM on the surface of mature B lymphocytes in mice, humans, and other species. It has been demonstrated that IgD also serves as a ligand for IgD-specific receptors (IgD-R) expressed on CD4 ϩ T cells and that deglycosylated IgD fails to bind to these receptors [1][2][3][4][5]. Moreover, N-acetylgalactosamine blocks the binding of IgD-R to IgD-coated target cells, suggesting that IgD-R have lectin-like properties [6 -8].…”