Immunological communications最新文献

Treatment of rat spleen cells with normal guinea pig serum (GPS) has been shown to produce a significant loss of responsiveness to stimulation with either Con A or PHA. This phenomenon was seen even when the spleen cells were triggered with mitogens up to 96 hr after treatment with GPS, suggesting that GPS had produced a long-lasting alteration in some cells or removed a cell subpopulation. Glass-wool non-adherent spleen cells, known to produce greater responses that unfractionated spleen cells, also had their responses to Con A and PHA reduced by GPS treatment though the response was still greater than that of untreated, unfractionated cells, suggesting that the actual responder cells had been spared by GPS. Suppressor cells did not appear to be the target of GPS because such an effect would have resulted in increased responsiveness and the opposite result was obtained. That a helper cell was affected by GPS was suggested by the following observations: a) the virtually unresponsive GPS-treated spleen cells produced greater than normal responses after removal of glass-wool-adherent suppressor cells; b) the response of glass-wool-nonadherent spleen cells was significantly decreased after GPS treatment; and c) mixtures containing equal numbers of glass-wool-nonadherent and GPS-treated spleen cells also showed reduced responsiveness after GPS treatment.

C3H/HeJ mice which had been primed with either virulent or killed T. pallidum were studied for in vivo delayed-type hypersensitivity (DTH) responses to T. pallidum following local footpad challenge. Mice sustaining a chronic infection of 5 months duration failed to develop a DTH to treponemal antigens, whereas priming by a single intravenous injection with killed organisms resulted in a significant DTH response in mice when challenged 5 days later. Treatment of mice prior to priming with a single sublethal dose of cyclophosphamide (100 mg/kg body weight) not only failed to potentiate T. pallidum-DTH, but abrogated the response observed in untreated primed animals.

A low-molecular weight compound N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7) resulted in strongly enhanced phagocytosis of polystyrene latex beads by peritoneal macrophages of BALB/c mice after intraperitoneal administration. Binding of C3 cleavage product (C3b) to peritoneal macrophages after intraperitoneal injection of W-7 was also enhanced as shown by fluorescent antibody technique. Antibody against W-7 was not detected in the sera of these mice. Therefore, close association of enhanced phagocytosis of polystyrene latex beads with increased binding of C3 cleavage product to macrophages was demonstrated through induction by a low-molecular weight compound in vivo.

Mice bearing a Lewis lung carcinoma (LLC) were passively immunized against prostaglandin E2 (PGE2) by administration of rabbit serum containing anti-PGE2 antibodies. The effect of PGE2-immune serum on the suppressed immunity of LLC-bearing mice was examined. Treatment of tumor-bearing mice with anti-PGE2 prevented the suppression of lymphocyte mitogenesis and the alterations in macrophage migration which typically occur in LLC-bearing mice. Furthermore, tumor growth was reduced in LLC-bearing mice which received antibodies directed against PGE2 rather than a placebo treatment.

HLA-DR antigens released by cultured human melanoma cells were harvested from spent medium. Antigenic activity was monitored by quantitative absorption analysis in the mixed hemadsorption assay using anti-HLA-DR rabbit antiserum. Following concentration by amicon filtration, and removal of insoluble components by centrifugation at 136,000 g, the spent medium was subjected to KBr (density, 1.23 g/ml) flotation. The antigenic material was enriched in the upper one-third fraction (lipoprotein-rich), by a factor of 7 with 79% recovery. Further purification of this upper fraction by sucrose (5-30%) density gradient resulted in a marked increase in antigenic activity in the bottom fraction (No. 6), by a factor of 167 with 56% recovery from the spent medium concentrate. Thus, these procedures offer a promising approach towards the isolation of HLA-DR antigens from shed material of cultured melanoma cells for further purification and structural studies.

Nuclear proteins synthesised by mouse lymphocytes stimulated by the B-lymphocyte mitogen lipopolysaccharide have been analysed by 2-dimensional polyacrylamide gel electrophoresis. It has been shown that the rate of synthesis of both nucleoplasmic proteins and nonhistone chromatin proteins is stimulated dramatically by LPS and many nuclear proteins are synthesised that were undetectable in resting lymphocytes. The majority of these proteins are synthesised by lymphoblasts and plasma cells, the lymphocytes that remain small after LPS stimulation synthesizing relatively few proteins. Two chromatin proteins that have previously been shown to appear in the nucleus within 4h of mitogen stimulation exhibit a continuous increase in their rate of synthesis during lymphocyte differentiation. The possible roles of these proteins in differentiating lymphocytes are discussed.

Procedures for isolation of antigenically active preparations of human HLA antigens were monitored using a sensitive and quantitative radioimmunoassay for HLA-A, B, C or HLA-DR antigens. These assays involve binding of radiolabeled monoclonal antibodies to appropriate target cells and inhibition of this binding by solubilized antigen preparations. Fixation of the target cells with glutaraldehyde allows quantitation of inhibitors in high concentrations of nonionic detergents. Using this assay, it was possible to examine quantitatively the relative merits of several alternative procedures for isolating both class I and class II antigens. For example, chromatography of cell lysates on columns of Ricinus communis agglutinin gave high recoveries of DR antigens purified from the majority of cell proteins. When Lens culinaris hemagglutinin was used for separation of cell lysates approximately 90% of the A, B, C antigens but only 32% of the DR antigens bound the column and were eluted by alpha-methyl-mannoside. Immunoadsorbent column were then used to recover antigenically active molecules suitable for structural or functional studies from these enriched fractions.

A monolayer of a clone of endothelial cells derived from rat lung cells (RLE) was overlaid with 1 M urea to extract the surface proteins. Hydrolysis and SDS-gel electrophoresis of the urea extracted cell surface proteins (UCSP) yielded four peptides of 350,000, 84,000, 66,000 and 18,500 molecular weight. Of these only the 66,000 and 18,500 molecular weight peptides reacted with antibodies raised in rabbit against rat lung endothelial cells (RLE). The 18,500 mol. wt. antigenic peptide was a serum protein associated with the cell surface, whereas the 66,000 mol. wt. peptide was the surface antigen synthesized and released into the medium by the rat lung endothelial cells. On rocket immunoelectrophoresis, the 66,000 mol. wt. rat kidney fibroblast surface peptide produced only a single rocket whereas peptides of RLE produced two rockets, suggesting the presence of an additional antigenic peptide which could serve as a marker for endothelial cells.

A mouse myeloma IgE protein was cross-linked with dimethylsuberimidate to induce polymerization and incubated with normal human peripheral blood T lymphocytes in tissue culture. After 24 hours at 37 degrees C approximately 30% of the cells formed rosettes with IgE sensitized red cells as compared with much lower levels in the controls. A variety of controls established that the cellular receptors involved in rosette formation were specific for IgE. Monomeric mouse IgE failed to induce a response.

We developed a method which provides a mechanism for isolating adherent mononuclear cells without subjecting them to traumatic physical or chemical methods of removal from their surface attachment sites. This method uses gelatin, which is solid at room temperature and liquid at 37 degrees C, as the adhering surface. Blood monocytes bind to gelatin-coated flasks at room temperature and are easily and gently removed when the gelatin is liquified at 37 degrees C. Monocytes, so isolated, are viable and functional [phagocytosis, adherence and Fc(IgG) and C3 receptor activity].