SUmlTlaryInterleukin-12 (IL-12) induces differentiation of T helper 1 (Thl) cells, primarily through its ability to prime T cells for high interferon-~/ (IFN-~) production. We now report that the presence of IL-12 during the first several days of in vitro clonal expansion in bruiting dilution cultures of polyclonally stimulated human peripheral blood CD4 + and CD8 + T cells also induces stable priming for high IL-10 production. This effect was demonstrated with T cells from both healthy donors and HIV(+) patients. Priming for IL-4 production, which requires IL-4, was maximum in cultures containing both IL-12 and IL-4. IL-4 modestly inhibited the IL-12-induced priming for IFN-% but almost completely suppressed the priming for IL-10 production. A proportion of the clones generated from memory CD45RO + cells, but not those generated from naive CD451KO-CD4 + T cells, produced some combinations of IFN-% IL-10, and IL-4 even in the absence of IL-12 and IL-4, suggesting in vivo cytokine priming; virtually all CD4 § clones generated from either CD45RO(-) or (+) cells, however, produced high levels of both IFN-~/and IL-10 when IL-12 was present during expansion. These results indicate that each Thl-type (IFN-~/) and Th2-type (IL-4 and IL-10) cytokine gene is independently regulated in human T cells and that the dichotomy between T cells with the cytokine production pattern of Thl and Th2 cells is not due to a direct differentiation-inducing effect of immunoregulatory cytokines, but rather to secondary selective mechanisms. Particular combinations ofcytokines induce a predominant generation ofT cell clones with anomalous patterns of cytokine production (e.g., IFN-~ and IL-4 or IFN-~/ and IL-10) that can also be found in a proportion of fresh peripheral blood T cells with "memory" phenotype or clones generated from them and that may identify novel Th subsets with iminunoregulatory functions.

SumnlaryThe production of cytokines in monocytes/macrophages is regulated by several different cytokines that have activating or inhibitory effects. Interleukin (IL)-10, IL-4, IL-13, and transforming growth factor (TGF)-~ are usually considered to be the most important macrophage-deactivating factors, with inhibitory effects on cytokine production. Unlike IL-IO and TGF-/3, which appear to act as downmodulators of many phagocytic cell functions, the mode of action of IL-4 and IL-13 is more complex. Addition of IL-4 and IL-13 to peripheral blood mononuclear cell (PBMC) cultures inhibited production of II.-12, tumor necrosis factor (TNF)-o~, IL-10, and II:1/~ induced by lipopolysaccharide (LPS) or Staphylococcus aureus added simultaneously with the cytokines. However, pretreatment of PBMC with II.-4 or I1.-13 for >--20 h enhanced the production of I1.-12 and TNF<~ in response to LPS or S. aureus several fold in these cells; this IL-4-induced priming for the two cytokines was inhibited by anti-IL-4 neutralizing antibodies. IL-4 priming also enhanced the accumulation of IL-12 and TNF-ot mR.NA induced by LPS and S. aureus. The enhanced accumulation of transcripts for the 1I.-12 p35 and p40 chains by IL-4 priming was reflected in enhanced secretion of both the IL-12 free p40 chain and the p70 heterodimer. These results suggest an unexpected complexity in the regulatory role of IL-4 and IL-13 in immune responses.

SummaryThe present study was designed to define molecules and structures involved in the interaction of natural killer (NK) cells with the vascular endothelium in vitro. Resting and interleukin 2 (IIs2)-activated NK cells were studied for their capacity to adhere to resting and 114-treated human umbilical vein endothelial cells (EC). In the absence of stimuli, NK cells showed appreciable adhesion to EC, with levels of binding intermediate between polymorphs and monocytes . The binding ability was increased by pretreatment of NK cells with 11,2. Using the appropriate monoclonal antibody, the (32 leukocyte integrin CD18/CD11a was identified as the major adhesion pathway of NK cells to unstimulated EC . Activation of EC with IIA increased the binding of NK cells. In addition to the CD18-CD11a/intercellular adhesion molecule pathway, the interaction of resting or IL2-activated NK cells to IL-1-activated EC involved the VLA-4 (a4131 )-vascular cell adhesion molecule 1 receptor/counter-receptor pair. No evidence for appreciable involvement of endothelial-leukocyte adhesion molecule was obtained . Often, NK cells interacted either with the culture substrate or with the EC surface via dot-shaped adhesion structures (podosomes) protruding from the ventral surface and consisting of a core of F-actin surrounded by a ring of vinculin and talin . The identification of molecules and microanatomical structures involved in the interaction of NK cells with EC may provide a better understanding of the regulation of NK cell recruitment from blood, their extravasation, and their migration to tissues.

Eight patients with epithelial ovarian carcinoma persisting after chemotherapy, selected for having a residual tumor no larger than 1 cm in diameter, were treated intra-peritoneally (i.p.) with recombinant interferon-gamma twice weekly for 3 months. Toxicity consisted of fever and malaise in all patients and a transient rise in hepatic enzyme levels in 3 patients. The cytotoxic function of peripheral blood and peritoneal tumor-associated lymphocytes (TAL) and macrophages (TAM), was studied using cell lines as targets. I.p. IFN-gamma augmented the cytotoxic activity of lymphocytes and mononuclear phagocytes: stimulation was more marked and more frequently observed with TAL and occasionally TAM than with blood effectors, suggesting preferential modulation at the site of tumor growth and IFN administration. Surgical laparotomy revealed that 1 patient had a complete response, 2 a partial response and 2 had stable disease, while 3 patients had progressive disease. In this small series of patients there was no obvious, strict correlation between immunomodulation by IFN-gamma and clinical response. These results indicate that, in contrast to its lack of activity in advanced ovarian carcinoma, IFN-gamma has definite immunomodulatory and antitumor activity in the presence of limited tumor burden.

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