RESUMEN
The effects of IFN-gamma on macrophage (M phi)-mediated antigen-specific T-cell proliferation was investigated. A well-defined assay system using purified resident populations of antigen-pulsed peritoneal M phi and immune T cells was used to measure M phi-induced antigen-specific T-cell proliferation. Antibody affinity purified or recombinant IFN-gamma inhibited M phi-induced T-cell proliferation when KLH-pulsed M phi from mice given IFN-gamma prior to KLH were cultured with KLH immune T cells from normal mice. Monoclonal rat anti-IFN-gamma antibody neutralized the inhibitory effect of IFN-gamma. This inhibition of T-cell proliferation occurred despite the fact that these M phi appeared to be activated by IFN-gamma treatment as measured by increased tumoricidal activity. The mechanism for the inhibition was unrelated to class II (Ia) expression, IL-1 secretion, and prostaglandin secretion. These results demonstrate the complex and sensitive role IFN-gamma has in regulating the immune response.
Asunto(s)
Epítopos/inmunología , Inmunosupresores/farmacología , Interferón gamma/farmacología , Activación de Linfocitos/efectos de los fármacos , Macrófagos/inmunología , Linfocitos T/inmunología , Animales , Anticuerpos Monoclonales/administración & dosificación , Citotoxicidad Inmunológica/efectos de los fármacos , Indometacina/farmacología , Interferón gamma/inmunología , Activación de Macrófagos/efectos de los fármacos , Ratones , Ratones Endogámicos CBARESUMEN
IFN-alpha/beta has been previously shown to cause the suppression of various immune responses. The reason for this immunosuppression, however, remains unknown. The studies described in this report demonstrate that treatment of mice with poly I:C or partially purified IFN alpha/beta inhibited the ability of KLH pulsed macrophages to induce proliferation of KLH immune T cells. This failure to generate antigen induced proliferation was not caused by the production of prostaglandins or other suppressive molecules by IFN treated macrophages, nor did this treatment induce suppressor macrophages.
Asunto(s)
Interferón Tipo I/farmacología , Activación de Linfocitos , Poli I-C/farmacología , Linfocitos T/inmunología , Animales , Antígenos , Indometacina/farmacología , Activación de Linfocitos/efectos de los fármacos , Macrófagos/inmunología , Ratones , Ratones Endogámicos CBARESUMEN
The cloned monocyte/macrophage cell line RAW 264.7 was previously shown to produce thymocyte mitogenic and co-mitogenic activity that eluted from a Sephadex G-75 column not only at approximately 16,000 daltons, the m.w. described for interleukin 1 (IL 1), but also at 30,000 to 40,000 daltons. The studies reported here indicate that the 30,000 to 40,000 dalton molecule has thymic differentiating activity. Thymocytes from A/J mice were fractionated on discontinuous BSA gradients, which yielded populations of cells enriched for immature and mature cells. The cells found at the interface between 35 and 29% BSA (band 1 cells), which are the most immature, were cultured for 48 hr with highly purified IL 1, with the 30,000 to 40,000 dalton form of thymocyte co-mitogenic activity obtained after Sephadex G-75 chromatography and chromatofocusing chromatography, or with media alone. The surface antigens TL-3, H-2Kk, Thy-1.2, Lyt-1, and Lyt-2 were examined by immunofluorescence. It was found that the highly purified 30,000 to 40,000 dalton species of co-mitogenic activity induced a significant increase in the content of surface H-2Kk, a decrease in TL-3, and a very small decrease in Thy-1.2 on the cell surface, whereas IL 1 was not capable of inducing a change in these surface antigens. There was no change in Lyt-1 on the surface of band 1 thymocytes after incubation with either IL 1 or the 30,000 to 40,000 dalton species. The 30,000 to 40,000 dalton species caused a significant decrease in the percentage of cells staining positive for Lyt-2, whereas IL 1 caused a smaller but significant decrease in Lyt-2. These changes in the surface markers TL-3, H-2Kk, and Thy-1.2 are consistent with changes that occur during thymocyte differentiation. It was also observed that the proliferative response to the 30,000 to 40,000 dalton form and IL 1 increased with increasing functional maturity of each band of thymocytes when used in the thymocyte mitogenic assay. However, only the 30,000 to 40,000 dalton form was capable of inducing a proliferative response in the immature band 1 thymocytes in the thymocyte co-mitogenic assay. These results indicate that the RAW 264.7 cells produce a factor that has, in addition to thymocyte co-mitogenic activity, thymocyte differentiation activity, and this factor is distinct from IL 1.
Asunto(s)
Antígenos de Superficie/análisis , Macrófagos/metabolismo , Mitógenos/farmacología , Monocitos/metabolismo , Linfocitos T/inmunología , Animales , Diferenciación Celular , Línea Celular , Cromatografía en Gel , Técnica del Anticuerpo Fluorescente , Lipopolisacáridos/farmacología , Activación de Linfocitos , Ratones , Ratones Endogámicos A , Ratones Endogámicos C3H , Mitógenos/aislamiento & purificación , Peso Molecular , Linfocitos T/citologíaRESUMEN
The cloned monocyte/macrophage cell line RAW 264.7 was investigated for interleukin 1 (IL-1) production. Of the inducers tested, bacterial lipopolysaccharide was found to be the most effective. The cyclic nucleotide analogs 8-BrcAMP and 8-BrcGMP were also tested, with only 8-BrcGMP being capable of inducing a small amount of IL-1 activity. Gel filtration studies revealed thymocyte mitogenic and comitogenic activity in three molecular-weight peaks: greater than 70,000, 30,000 to 40,000, and 12,000 to 18,000 Da. The multiple-molecular-weight forms were present when samples were prepared under serum-free conditions and also when samples were prepared and chromatographed in high ionic strength NaCl or under disulfide reducing conditions. Molecular charge heterogeneity was observed when proteins were chromatographed using column chromatofocusing (PBE 94). The intermediate-molecular-weight form eluted from the column over a pH range of 5.0 to 5.4; while the low-molecular-weight form eluted at three separate pH's: greater than or equal to 7.4 (unbound material), 5.2, and 4.8. The low-molecular-weight and intermediate-molecular-weight forms exhibited different dose-response curves when assayed under conditions used by other investigators (1 X 10(7) cells/ml; phytohemagglutinin, 1 microgram/ml), but very similar dose-response curves when assayed under conditions used by our laboratory (2 X 10(6) cells/ml; concanavalin A, 0.25 microgram/ml) in a thymocyte comitogen assay. The possible relationship of these multiple-molecular-weight species of thymocyte comitogenic activity from RAW 264.7 to other biological activities from cloned and noncloned cellular sources is discussed.