Tritiated thymidine incorporation was measured after a 48-h culture. GIPL has a direct stimulatory effect on NK cells and induces immunoglobulin secretion in the absence of T lymphocytes and NK cells. These findings suggest that this illness. Glycoinositolphospholipids (GIPLs) are some of the major glycoconjugates present within the cellular surface of (17) and different strains Becampanel of (6). GIPL was shown to contain a glycan moiety linked through a non-inhibits the leishmanicidal activity of murine macrophages (21), and the GIPL induces macrophage apoptosis in the presence of gamma interferon (IFN-), a process that is definitely associated with improved parasite launch (10). GIPL blocks T-cell reactions induced by different polyclonal activators (11), while it activates murine B cells in vitro (2). In the absence of added costimuli, the G strain GIPL stimulates detectable immunoglobulin M (IgM) production by both low- and high-density B cells and potentiates the response induced by either surface Ig ligation or cytokines. The B-cell stimulatory effect of the GIPL is definitely mediated primarily by its oligosaccharide moiety (2). Illness with is definitely associated with a polyclonal B-cell activation, and improved circulating Ig levels are recognized both early during illness and throughout the chronic phase (8, 27). A transient increase Becampanel in NK cell cytotoxic activity is also observed during illness (13), and NK cells have been described as becoming necessary for resistance to illness, probably due to the secretion of IFN- (5). Besides their part in the resistance against different infections because of the cytotoxic activity, NK cells have an important part in regulating B-cell activation. Therefore, in vitro polysaccharide antigen-induced B-cell response requires the presence of NK cells (25). This accessory part is definitely mediated both from the secretion of cytokines from the NK cells and by B-lymphocyteCNK cell contact (12, 25). A earlier study (2) showed the inositol (PIns)-oligosaccharide derived from the G strain GIPL has a stimulatory effect on B cells. However, the requirement for accessory cells in the induction of B-cell activation had not been addressed yet. In the present study, we investigated the effect of the GIPL on B cells purified from mice deficient in both T lymphocytes and NK cells (30). The part of NK cells in the GIPL-induced B-cell Rabbit polyclonal to EFNB2 response was assessed by Becampanel using an NK cell collection recently explained to enhance Ig secretion in an in vitro model of T-cell-independent type 2 (polysaccharide) antigen (29). CD3? transgenic (tg) mice [B6,CBA-TgN(CD3E)26Cpt] were from the Jackson Laboratories (Pub Harbor, Maine); the strain used offers irregular differentiation of both T lymphocytes and NK cells, lacking mature peripheral NK and T cells (29). Mice were used at 8 to 12 weeks of age. The experiments were conducted according to the principles set forth in the (18a). The dextran-conjugated anti-IgD antibody (anti-delta-dextran) was prepared by the Becampanel conjugation of the AF3 anti-IgD monoclonal antibody (28) to high-molecular-weight dextran, as previously explained (4). Murine recombinant interleukin-2 (IL-2) (specific activity, 1.6 106 U/mg) and murine recombinant IL-12 (heterodimeric form) were from Genzyme Corporation (Cambridge, Mass.). Splenic B cells were acquired by discontinuous Percoll gradient fractionation (7, 22). Gradients consisting of 70, 60, and 50% Percoll (with densities of 1 1.086, 1.074, and 1.062 g/ml, respectively) were used. The cells were collected from your 70 to 60% interface after centrifugation (1,900 for 15 min). The B-cell preparation acquired after Percoll fractionation was composed of 95% B cells and 5% non-B cells (data not demonstrated). The B cells were cultured for 7 days in RPMI 1640 supplemented with 10% fetal calf serum (GIBCO, Grand Island, N.Y.), l-glutamine (2 mM), 2-mercaptoethanol (50 M), nonessential amino acids (100 M), sodium pyruvate (1 mM), and gentamicin (50 g/ml) (total RPMI medium), in a final volume of 200 l in flat-bottom 96-well trays (Costar, Cambridge, Mass.). Quantification of IgM was performed by a modification of a previously explained capture Ig enzyme-linked.