Antigen-specific activation of human T-cells: The role of monocytes and monocyte subpopulations

464

/ THIRD

INTERNATIONAL

WORKSHOP

ON

CYTOKINES

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88

ANTIGEN-SPECIFIC ACTIVATION OF HUMAN T-CELLS: THE ROLE OF MONOCYTES AND MONOCYTE SUBPOPULATIONS D.Lorenzen, E.Graae. FLFettina. H.-D.Flad. and M.Ernst Forschungsinstitut Borstel, Department of Immunology and Cell Biology, D-2061 Borstel, FRG We investigated the participation of different monocyte and lymphocyte subsets in the induction and augmentation of IFN-y production in human T-cells. Elutriationderived highly purified monocytes (>95% CD1 4+) from tuberculin (PPD) skin test positive and negative individuals were used as antigen presenting cells. Only CD3 CD4+CD6CD1 6- T-cells from PPD skin test positive donors responded to PPDpulsed monocytes with significant production of IFNy. However, upon polyclonal stimulation with anti-CD3 moAb or with PHA T-cells (CD4+ and CD8+) from both PPD skin test positive and negative donors produced IFN-y. IFN-y production of total T-cells or defined subpopulations required the participation of monocytes and could be enhanced by increased proportions of monocytes. Further separation of elutriated monocytes into CD84+ (Fc-y-R I) and CD64- monocytes indicated that CD64- monocytes were more efficient to induce IFN-y in human T-cells. Furthermore, increased numbers of CD64+ monocytes added to CD8+ T-cells resulted in a significantly lower IFNy production of CD4+ T-cells. We conclude from our data that CD84 and CD64- monocytes play an important regulatory role in antigen specific T-cell lymphokine r&aSe. Supported by grant 01 KI 88276 of BMFT

INTRACELLULAR

THELIAL

CELL

ROLE

PROLIFERATION

OF INTERLEUKIN

AND

1 ALPHA

IN

REGULATING

HUMAN

ENOO-

SENESCENCE.

Maier+*, R. Cece+, 7. Baciag* and G. Ragnotti+ +Unit of General ogy and Immunology, University of Erescia. I-25123 Erescia and *Laboratory nolecular Biology, American Red Cross, Rockville, 20855 Md, U.S.A. Interleukin 1 alpha (IL 11, a polypeptide regulator of immune function

J.A.H.

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89

86

RECEPTOR AWTAGONIST(S)DERIVEBFRGM GLUCOCORTICOID-TREATED ACCESORYCELLS. M. L. Lukid and S. IL-l

POTENTIAL

RECEPTOR AND

IL-~

St&i&Gruji~i6. Inst.Microbiol.Inxnunol.,School of Medicine and Inst.Biol.Res., 11000 Belgrade, Yugoslavia. Regulatory effects of glucocorticoids (GCs) on the production of monokines was examined by analyzing the bioactivity of the supernatants derived from human monocytes, rat peritoneal IQ, as well as human and rat keratinocytes, which were exposed to various synthetic GCs. In agreement with previous findings, all supernatants examined did not contain detectable amounts of IL-l and IL-6, as determined by DlOS and Bg assays, respectively. Additionaly, these GC-free supernatants suppressed in dose-dependent fashion specific responses to IL-1 and IL-~. Lysates prepared from the same GC-treated cells lack this activity. The IL-l antagonist was further asz@;“.sL~; ;;;;titive inhibition assay using DIOS cells and After fractionation on sephadex G-50 column that separated IL-l and IL-l antagonist molecules, it was shown that inhibitory molecule expressed IL-l-receptor antagonist activity. The presence of functional IL-1-ra was demonstrated in all GC-treated accessory cell-derived supernatants (MO, MO and keratinocytes). It still remains to be established whether IL-l-pa and IL-6-ra activity induced by GCs are mediated by different molecules. Thus, our data provide further support for important interaction of GCs with accessory cells, suggesting that GC-induced IL-1 and IL-6 antagonists may be in viva mediators of antiinflammatory and immunosuppressive -effects of GCs. (Supp. by RSF, Belgrade).

90

87 SAMONELLA-INDUCED BY MACROPHAGES RESISTANT MOUSE

BCGF PROMOTES IL-2-INDUCED PROLlFERA-I’lON OF CD.56+ AND CD3+ LYMPHOCYTES IN VITRO A.Malvein. P.Kovanen. T.Timonen Dept. of Pathology, Univ.of Helsinki, SF-00290. LMW-BCGF, a 12 kD protein, is presently known as one of the B-cell growth factors. We investigated the influence of BCGF on the growth of T lymphocytes and non-MHC-restricted killer cells in culture. The addition of 5% of BCGF to PBL resulted in the expression of Tat receptors on both CD56+(82%) and CD3+(76%) cells after one week of culture, but cell proliferadon required the presence of rIL-2. The cell proliferation was most profound with the combination of BCGF and IL-2, and cell numbers exceeded those of IL-2-supplemented cultures 2-10 fold. The addition of BCGF did not influence the frequencies of CD3+ and CD56+ cells, nor LAK activity. During 3 weeks, the combination of BCGF and rIL-2 increased the total amount of lymphocytes up to 200-400 fold. These results show that BCGF is potent stimulator of lymphocyte proliferation in vitro.

PRODUCTION OF CYTOKINES FROM SUSCEPTIBLE AND STRAINS. Pi. A. Arena

aP.a

University of Messina, I-98100 Messina, Italy. We have previously shown that TNFa plays an important role in murine salmonellosis. The present work was undertaken to analyze the factors involved in the production of TNF’a, IL-l and IL-6 by mouse macrophages stimulated in vitro with Salmonella typhimurium. Monolayers of peritoneal macrophages from genetically resistant (CBA) and susceptible (BALB/c) mice were infected with the M525 RP4 strain of S. typhymurium opsonized with normal mouse serum at a bacteria to cell ratio of 1O:l. Kinetic studies revealed that considerable amounts of TNF’a, IL-1 and IL-6 were produced with peak levels at about 10 h after the addition of bacteria. No significant differences were noted in the amounts of IL-1 and IL-6 produced by CBA and BALB/c. On the contrary, macrophages from CBA secreted significantly higher levels of TNFa than those from BALB/c. Genetic resistance to murine salmonellosis may be related to a differential ability to produce TNFa in response to Salmonella infection.

COMBINED EFFECT OF INTERLEUKIN 2 AND PROLACTIN ON GENERATION OF LAK ACTIVITY BY NK CELLS L. Matera, G. Bellone, A. Cesano and E. Oberholtzer Institute of Internal Medicine, University of Turin, 10126 Turin, Italy We have previously shown that NK cells express membrane receptors for the hormone Prolactin (Prl) and that binding of the hormone is followed by changes in both the native MHC-unrestricted killing and the spontaneous DNA syntesis the hormone enhances of these cells. Here we show that the response of NK cells to the specific growth factor Both the generation of cytotoxicity INterleukin 2 (ILZ). against NK resistant cells lines and the 3H-TdR uptake by ILZ-stimulated NK cells were significantly increased in the presence of physiological to supra-physiological (12-25 rig/ml) of Prl. The combined use of sub-optimal concentrations of both factors was very effective in inducing high levels of LAK activity. The effect of Prl on the IL2

responsiveness

of

the

of

NK

cells

was

secondary

to

up-regulation

alpha-chain ILZ-receptor (0725, TAC). Remarkable levels of LAK activity wre also observed when NK cells were cultured with Prl alone. These results indicate that Prl act as a growth/differentiating factor for NK cells.