P Pr ro od du uc ct ti io on n o of f I IL L--1 1 a an nd d i it ts s r re ec ce ep pt to or r a an nt ta ag go on ni is st t i is s r re eg gu ul la at te ed d d di if ff fe er re en nt tl ly y b by y I IF FN N--γ a an nd d I IL L--4 4 i in n h hu um ma an n m mo on no oc cy yt te es s a an nd d a al lv ve eo ol la ar r m ma ac cr ro op ph ha ag ge es s ABSTRACT: Interleukin-4 (IL-4) has previously been found to downregulate interleukin-1 (IL-1) production, but to upregulate the production of IL-1 receptor antagonist (IL-1ra) in human monocytes stimulated with lipopolysaccharide (LPS). In the present study we wanted to determine whether the production of IL-1ra in human monocytes and alveolar macrophages (AMs) is regulated differently at the protein and messenger ribonucleic acid (mRNA) levels by IL-4 and interferon-γ (IFN-γ).AMs and monocytes obtained from healthy donors by bronchoalveolar lavage and centrifugal elutriation were stimulated with LPS in the presence or absence of IL-4 or IFN-γ, and the expression of mRNA for IL-1 and IL-1ra was measured by Northern blot analysis. The production of IL-1 and IL-1ra was quantitated by enzyme immunoassays (EIAs).Spontaneous IL-1ra production was seen in AMs after incubation for 4 h in medium alone, but not in blood monocytes, at both the protein and mRNA levels. The spontaneous expression of the IL-1ra gene in AMs was augmented by incubation with IL-4. Interleukin-1β (IL-1β) production by LPS-stimulated AMs and monocytes was upregulated by IFN-γ, but downregulated by IL-4. Interestingly, when stimulated with LPS, IFN-γ inhibited IL-1ra production by monocytes, but up-regulated its production in human AMs at the protein and mRNA levels.These results suggest that the production of IL-1 and IL-1ra by monocytemacrophages is regulated differently at the mRNA level, depending upon the balance between the production of IL-4 and IFN-γ at the sites of T-cell/macrophage interactions in the lung. Eur Respir J., 1994, 7, 657-663.

Highly purified lymphocytes (greater than 99%) and monocytes (greater than 90%) were isolated by CCE from peripheral blood of healthy donors. Blood lymphocytes were separated by this CCE into 9 subpopulations. The NK activities of these lymphocyte fractions against NK-sensitive K-562 cells and their LAK activities against NK cell-resistant target (Daudi) cells were assayed promptly or after incubation of the fractions for 4 days with or without an optimal concentration of IL-2. NK and LAK activities were measured by 4-hr 51Cr-release assay. On the basis of their NK and LAK activities, these lymphocyte fractions were classified into 3 subpopulations of LAK precursors: one lacking both NK and LAK activities (Fr.2), one with moderate NK activity but low LAK activity (Fr.5), and one possessing both NK and LAK activities (Fr.8). Addition of autologous fresh monocytes to the lymphocyte cultures resulted in a significant increase in induction of LAK activity in Fr.2 and Fr.5. This up-regulation of lymphocytes in Fr. 2 and Fr.5 by monocytes was confirmed in parallel experiments by measuring the blastogenic response of the lymphocytes to IL-2. Deletion of lymphocytes in Fr. 8 of CD16+ (Leu-11+) NK cells resulted in 74% reduction in LAK induction, whereas depletion of mixtures of monocytes and lymphocytes in Fr. 2 of cells reacting with CD3+ (OKT3+) antibody resulted in a 66% reduction in LAK induction. This up-regulation of LAK cell induction from LAK precursors by monocytes was confirmed using 4 lines of human lung cancer cells as targets for LAK activity. These results clearly indicate that human monocytes may cause up-regulation of the expression of IL-2-induced LAK activity in T cells and in a subpopulation of NK cells.

Freshly isolated human peripheral blood monocytes from healthy volunteers are not cytotoxic to allogeneic A375 melanoma cells, but they were rendered tumoricidal by incubation in vitro with either liposomes containing 5 micrograms/mumol phospholipid of muramyl tripeptide phosphatidylethanolamine (liposome-MTP-PE; optimal dose, 500 nmol/ml) or recombinant human interferon gamma (rIFN-gamma; optimal dose, 100 U/ml). A combination of sub-threshold concentrations of liposome-MTP-PE (50 nmol/ml) and rIFN-gamma (1 or 10 U/ml) also induced significant tumor-cell killing, indicating that the effects of rIFN-gamma and liposome-MTP-PE in monocyte activation are synergistic. In contrast to rIFN-gamma, recombinant IFN-alpha and IFN-beta had additive effects with liposome-MTP-PE in human monocyte activation. Since recombinant human IFN-gamma has a synergistic effect with liposome-MTP-PE in monocyte activation, unlike IFN-alpha or IFN-beta, and liposome-MTP-PE as well as rIFN-gamma is available at standardized concentrations, this combination could be of clinical value in the treatment of disseminated malignant disease.

Mononuclear cells (MNC) from pleural effusions and peripheral blood of 18 patients with primary lung cancer with malignant pleural effusion were studied. Pleural and blood MNC generated lymphokine‐activated killer (LAK) activity similarly when cultured for 4 days with an optimal concentration of interleukin 2 (IL‐2). Highly purified lymphocytes (>98%) and monocyte‐macrophages (>90%) were isolated by discontinuous Percoll gradient centrifugation from pleural and blood MNC. Pleural macrophages, as well as blood monocytes, showed significant augmenting effects on in vitro LAK cell induction from pleural and blood lymphocytes by IL‐2. During daily intrapleural administration of IL‐2, significant induction of LAK activity in vivo was observed after 3 days, but then this LAK activity in pleural MNC decreased almost to zero by day 15. Daily injections of IL‐2 resulted in reduction in the up‐regulation of LAK induction by pleural macrophages and also in increase in the levels of soluble IL‐2 receptors in pleural effusions. These findings indicate that in vivo LAK induction of lymphocytes in malignant effusions by IL‐2 may be regulated by macrophages in the effusions.

Cell‐to‐cell interaction between tumors and host inflammatory cells is important for the subsequent cancer progression or regression. We examined the expressions of mRNAs for various proinflammatory cytokines by nine human lung cancer cell lines and the influences of cytokines on their gene expressions. The cytokines used were interleukin 1β (IL‐1β), interleukin 6 (IL‐6), tumor necrosis factor α (TNF‐α), granulocyte‐macrophage colony stimulating factor (GM‐CSF) and monocyte chemotactic and activating factor. Gene expressions of cytokines were measured by Northern blot analysis. Substantial expressions of cytokine genes were detected in several lung cancer cell lines such as RERF‐LC‐MS, RERF‐LC‐OK and VMRC‐LCD, although the levels of expression of each cytokine varied in different cell lines. Four lung cancer cell lines (RERF‐LC‐MS, RERF‐LC‐OK, A549 and YO‐88) were used to examine the effects of exogenous cytokines (IL‐1β, TNF‐α and GM‐CSF) on cytokine gene expressions by the cells. TNF‐α and IL‐1β caused significant changes in the levels of mRNA expressions of certain cytokines. Moreover, on stimulation with TNF‐α, RERF‐LC‐OK cells produced IL‐6 extracellularly. These extensive differences in the levels of gene expressions and productions of cytokines could have profound effects on the interactions between human lung cancer cells and the corresponding host cells.