Production of natural killer cell stimulatory factor (interleukin 12) by peripheral blood mononuclear cells.

Abstract

SummaryNatural killer cell stimulatory factor (NKSF), or interleukin 12 (IL 12), is a 70-kD heterodimeric cytokine composed of two covalently linked chains, p40 and p35 . NKSFAL 12 has multiple effects on T and NK cells and was originally identified and purified from the supernatant fluid of EpsteinBarr virus (EBV)-transformed human B lymphoblastoid cell lines. We have produced a panel of monoclonal antibodies against both chains of NKSFAL 12 . Some of these antibodies have neutralizing activity, and several combinations of them have been used to establish sensitive radioimmunoassays detecting the free p40 chain, the free p35 chain, or the p70 heterodimer. Using these reagents, we have determined that most EBV transformed human B lymphoblastoid cell lines constitutively produce low levels of the p70 heterodimer and an excess of the free p40 chain, whereas Burkitt lymphoma-derived, T, myeloid, and many solid tumor-derived cell lines produce neither. Production of both p40 and p70 is increased several-fold upon stimulation of the EBVtransformed cell lines with phorbol diesters . The ability of supernatant fluids from unstimulated and phorbol diester-stimulated cell lines to induce interferon y (IFN-y) production from T and NK cells, one of the effects of NKSFAL 12, parallels the levels of production of the p70 heterodimer, known to be the biologically active form of NKSFAL 12 . Staphylococcus aureus Cowan I strain (SAC) and other stimuli induce accumulation of p40 mRNA and production of both p40 and p70 by peripheral blood mononuclear cells (PBMC) . The producer cells appear to include both adherent cells and nonadherent lymphocytes, possibly B cells. The supernatant fluids from SAC-stimulated PBMC mediate the typical functions of NKSFAL 12 (i.e., IFN-y induction, mitogenic effects on T/NK blasts, enhancement of NK cell cytotoxicity) at concentrations of p70 similar to those at which recombinant NKSFAL 12 mediates the same functions . Moreover, these activities are significantly inhibited by anti-NKSF/IL12 antibodies . The neutralizing anti-NKSF/IL12 antibodies also inhibit 85% of the IFN-y production in response to SAC, an NKSF/IL 12 inducer, and approximately 50% of the IFN-y production in response to non-NKSF/IL12-inducers such as IL-2, phytohemaglutinin, and anti-CD3 antibodies . These results indicate that induced or constitutively produced NKSFAL12 has a major role in facilitating IFN-y production by peripheral blood lymphocytes . Our findings that NKSFAL 12 is both spontaneously produced and inducible in adherent PBMC and lymphocytes suggest that NKSFAL 12 might be a major physiological regulator of T and NK cell function during an immune response and inflammation .i A. D'Andrea and M . Rengaraju contributed equally to this work . 1387J . Exp. Med .

Mannosylated Lipoarabinomannans Inhibit IL-12 Production by Human Dendritic Cells: Evidence for a Negative Signal Delivered Through the Mannose Receptor

“…Indeed, in humans, IL-12 deficiency leads to a predisposition to mycobacterial infections despite the formation of mature granulomas (3). Surprisingly, M. tuberculosis, the causative agent of human tuberculosis, induces IL-12 production in vitro from murine phagocytic cells (38) and human DCs (39) and in vivo at the human infection site (40). The M. tuberculosis 19-kDa lipoprotein was found to be the potent stimulator of TLR-2-dependent IL-12 production by human macrophages (41).…”

CD4 T Cell-Mediated Alloresistance to Fully MHC-Mismatched Allogeneic Bone Marrow Engraftment Is Dependent on CD40-CD40 Ligand Interactions, and Lasting T Cell Tolerance Is Induced by Bone Marrow Transplantation with Initial Blockade of this Pathway

“…CD8 ϩ CTL activation that is independent of CD40L/CD40 interactions occurs by both CD4 Thdependent (35) and CD4 cell-independent pathways (34, 36 -38) and in the absence of CD4-mediated APC conditioning (31-34, 39 -41). CD4 cell-independent APC activation can occur via LPR (42)(43)(44), C3R (45), Fc␥R (46), and CpG oligodinucleotides (45,(47)(48)(49), and these pathways are associated with the production of mediators of CD8 T cell activation, such as type I IFNs (44,46,50), TNF-␣ (51), IL-12 (52)(53)(54)(55)(56)(57), and IL-15 (58). Thus, we hypothesize that the failure to achieve engraftment in a proportion of animals receiving BMT with costimulatory blockade as the only immunosuppression may reflect such "bypass activation" of APCs due to exposure to microorganisms that cannot be controlled, and that this activation leads to the Th-independent activation of alloreactive recipient CD8 cells that then reject the donor marrow and prevent tolerance induction.…”

IL-23 Production by Cosecretion of Endogenous p19 and Transgenic p40 in Keratin 14/p40 Transgenic Mice: Evidence for Enhanced Cutaneous Immunity

“…This proinflammatory cytokine is mainly produced by activated dendritic cells, monocytes, and keratinocytes (KC) 2 (1)(2)(3)(4). Apart from its capacity to enhance proliferation and cytotoxicity of T and NK cells, IL-12 commits differentiation of naive CD4 and CD8 T cells to cells that preferentially produce IFN-␥ and IL-2 (T1 cells) (5,6).…”