摘要:

SummaryElicited, mouse peritoneal exudate cells were fractionated by centrifugation on discontinuous Percoll density gradients. Two subpopulations of neutrophils, each of greater than 90% purity, were isolated at discontinuous density gradient interfaces different from the region of mononuclear cell enrichment (i.e., 1.0694‐1.0871 and 1.0872‐1.1002 g/ml for neutrophils and less than 1.0694 g/ml for mononuclear cells). Peritoneal exudate cells were mixed withProteus mirabilisin the presence of 1% normal mouse serum for 30 min. The mixtures were fractionated on gradients of Percoll diluted with a clacium‐free medium. Populations of cells banding at densities greater than 1.0693 g/ml were washed free of gradient material, and neutrophil suspensions containing intracellular bacteria and which were relatively free of extracellular bacteria were isolated. Less than 7% of the total bacteria present was extracellular. The continuing extracellular presence of a heat‐labile component of normal mouse serum was essential for maximal intracellular kill ofP. mirabilisby mouse peritoneal neutrophils.

ISSN:0004-945X    

DOI:10.1038/icb.1985.42

出版商:Nature Publishing Group    

年代:1985

数据来源: WILEY

摘要:

SummaryInbred mice fed with a 40% mixture of palmyrah flour pellets showed a significantly reduced capacity to mount a delayed‐type hypersensitivity (DTH) response to sheep red blood cells (SRBC). Maximal suppression of DTH was noted after 6 days of feeding but was detectable even after 2 days. Maximal suppression occurred when flour feed was maintained into the sensitization period (with SRBC). The suppressive effect was transferable to normal mice fed with pelletsad libitumby viable spleen cells from mice fed with the 40% flour pellet mixture for a period of 2 days. Further characterization of the cells which were able to transfer suppression showed them to be T cells, some of which possess the Ly‐1 surface antigen. The cells appear to be negative for Ly‐2 surface antigen. Historically, no evidence of lesions was noted in the liver and other organs of recipient mice which received cells from flour‐fed donors. We thus favour the interpretation that oral feeding of mice with palmyrah flour induced the generation of T suppressor cells which were able to suppress the DTH response to SRBC. The significance and implications of these findings are discussed.

ISSN:0004-945X    

DOI:10.1038/icb.1985.43

出版商:Nature Publishing Group    

年代:1985

数据来源: WILEY

摘要:

SummaryThe cannulated prescapular lymph node of the foetal lamb was challenged with killedBrucella abortus.Usually, both efferent prescapular ducts were cannulated and one node left as a control. Nodes were given primary or secondary challenges with doses of 109‐ 2 × 1010brucella organisms and the lymph‐borne response of the nodes followed.The foetal lymph node produced a vigorous cellular response to the injected brucella, restricted to the challenged side. The total cell output and, more strikingly, large cell output increased to reach a peak value 4‐5 days after challenge. This cellular response was seemingly dose‐dependent.The output of antibody after a primary challenge was delayed considerably and could not be detected in the lymph until well after the cellular response had subsided. The concentrations of antibody produced were quite low and almost all mercaptoethanol‐sensitive. With secondary challenges the output of antibody occurred much more quickly, in phase with the cellular response, and appreciable amounts of mercaptoethanol‐resistant antibody were produced.Under exceptional circumstances, high titre, highly specific anti‐brucella antibody has been produced in foetal lymph. The foetal lymph node provides a powerful tool for further studies of the ontogeny of the immune response, and might help elucidate the failure of newborn animals to respond to some important bacterial antigens.

ISSN:0004-945X    

DOI:10.1038/icb.1985.44

出版商:Nature Publishing Group    

年代:1985

数据来源: WILEY

摘要:

SummarySurgical techniques are described for the long‐term collection of lymph from both prescapular efferent lymph duels of foetal lambsin utero. Lymph ducts in foetal lambs 95 to 136 days post‐conception were cannulated with a high rate of success. Lymph flow from the cannulas was not compromised by deliberate primary or secondary challenge of the lymph nodes with a wide variety of antigens, and often continued for long periods after the lambs were born naturally. The techniques allow cellular and humoral lymph‐borne immune responses of foetal lambs to authentic primary antigenic challenge to be studiedin utero, uncomplicated by any previous experience of antigens. Loss of lymphocytes from the cannulated ducts depleted the numbers of cells in the lymph, but lymph protein concentrations were unaffected by lymph drainage.

ISSN:0004-945X    

DOI:10.1038/icb.1985.45

出版商:Nature Publishing Group    

年代:1985

数据来源: WILEY

摘要:

SummaryLeishmania donovanipromastigotes were found to release excretory‐secretory antigens (ESA) in the culture medium which reacted against rabbit antiserum to live promastigotes (RA‐LP). The active material was purified and found to contain mainly polysaccharides with about 23% of protein. A polysaccharide‐rich antigen (PRA) was also isolated from the promastigote debris by the phenol‐water extraction procedure. When tested against RA‐LP in agar gel diffusion, both the preparations were found to be antigenically identical to each other as well as to a preparation of crude soluble antigen (CSA). The determinants involved were shown to be polysaccharide in nature. Gel filtration of all the three preparations showed that the antigenic activity was distributed in various eluted fractions. Both CSA and PRA also exhibited considerable electrophoretic heterogeneity in immunoelectrophoresis, although ESA showed only two overlapping faster moving bands. It is concluded that ESA represented a mixture of highly negatively charged mucopolysaccharides of varying sizes. The minimum molecular weight of the basic structural unit was around 2 × 104daltons. These materials were probably derived from antigenically similar complexes of larger molecular weights located on the outer surface of the parasite and were released in the culture medium during their multiplication. Information available so far from this study suggests that the polysaccharide determinants of ESA/PRA did not elicit any marked immune response in kala‐azar patients.

ISSN:0004-945X    

DOI:10.1038/icb.1985.46

出版商:Nature Publishing Group    

年代:1985

数据来源: WILEY

摘要:

SummaryVarious preparations of somaticNematospiroides dubiusantigens were emulsified in Freund's complete adjuvant and assayed in Quackenbush mice for efficacy as vaccines against homologous infection. Soluble and particulate fractions were given by two different routes. Only minimal protection was induced by vaccination with either soluble or particulate parasite fractions used independently when compared with the adjuvant control. Fewer and smaller worms were recovered from, and significantly fewer parasite eggs were voided by, mice which had been treated previously with both soluble somatic protein (15 μgN. dubiusper mouse) by the intraperitoneal route and particulate antigen by subcutaneous injection These mice showed higher antibody titres in comparison with other mice treated with either fraction alone. Further, treatment with both antigen fractions together appeared to exert a synergistic effect in comparison with either fraction administered alone.

ISSN:0004-945X    

DOI:10.1038/icb.1985.47

出版商:Nature Publishing Group    

年代:1985

数据来源: WILEY

摘要:

SummaryWe describe a mycoplasma‐free human fibrosarcoma cell line, MR‐83, which glows readily in liquid culture and as clones in semi‐solid agar with a plating efficiency of about 0.5%. It has a stable karyotype consisting of a modal number of 49‐51 chromosomes, with two translocations and a deletion. The cell line shows resistance to adriamycin in semi‐solid agar assay, and responds to Epidermal Growth Factor (EGF) by increased DNA synthesis, as measured by thymidine uptake.

ISSN:0004-945X    

DOI:10.1038/icb.1985.48

出版商:Nature Publishing Group    

年代:1985

数据来源: WILEY

摘要:

SummaryIn vivothe majority of sympathetic neurones are adrenergic, whereasin vitrothey can become cholinergic. This atypical cholinergic development can be suppressed by addition of a glucocorticoid to the culture medium (McLennan, Hill and Hendry, 1980). In this paper we have investigated the possibility that glucocorticoids influence the choice of sympathetic transmitter typein vivo. Reduction in circulatory glucocorticoids by adrenalectomy of 2‐day‐old rat pups did not result in increased cholinergic development in their superior cervical ganglia. Furthermore, administration of exogenous corticosterone to increase circulatory glucocorticoids in young rats did not prevent the developmental switch in transmitter type of the sympathetic innervation of the sweat gland from adrenergic to cholinergic. It is concluded that the developmental regulation of sympathetic transmitter typein vitromay not be analogous to thatin vivo.

ISSN:0004-945X    

DOI:10.1038/icb.1985.49

出版商:Nature Publishing Group    

年代:1985

数据来源: WILEY

摘要:

SummarySodium permeability (P22Na) and steady state transepithelial concentration differences of Na (ΔcNa) were measured in stationary droplets in proximal tubules of rats in both the non‐expanded (NE) and subsequent mannitol‐saline volume‐expanded (VE) state. The test solutions for tubular injection were either an artificial tubular solution (AS) in group I rats or harvested proximal tubular fluid (HTF) in a second group of rats (group II) ΔcNa(mmol.kg‐1H2O) was significantly reduced (p<0.001) with HTF in the VE state (12.1 ± 0.8 SEM) when compared to HTF in the NE state (17.8 ± 1.8) and AS in both NE (17±4. 1.0) and VE (18.2 ± 1.0). P22Nacalculated from the half‐time of disappearance of22Na from the droplets, when using paired experiments were 8.1 ± 1.7×10‐5mm2.sec‐1and 7.3 ± 1.8 with HTF in NE and subsequent VE and 8.6 ± 1.1 and 7.7 ± 0.8 with AS in NE and VE. These permeability results did not differ from each other significantly. In these experiments with zero net Na and water fluxes, the 32% reduction of ΔcNacannot be accounted for by an increased backleak of Na, since P22Nawould have had to increase by 32%. These results therefore provide strong evidence for a factor present in proximal tubular fluid consequent upon VE which inhibits Na transport without altering transcpithelial PNa, but do not exclude an effect of such a factor on the cellular Na entry step or the Na pump itself.

ISSN:0004-945X    

DOI:10.1038/icb.1985.50

出版商:Nature Publishing Group    

年代:1985

数据来源: WILEY

摘要:

SummaryProduction of diffusible pigment in a strain ofStaphylococcus aureus(WG260) has been associated with a plasmid of c.26 megadaltons which can be co‐transduced with inducible erythromycin and spectinomycin resistance. However, the diffusible pigment plasmid can be lost from the transductants without loss of inducible erythromycin and spectinomycin resistance. The evidence suggests that the resistance determinants are located on an element similar or identical to transposon Tn554, and, during transduction of the diffusible pigment plasmid, a copy of the resistance determinants always inserts into the chromosome of the transductant. This is the first report of such an element occurring on a plasmid in a clinical isolate ofS. aureas. To date, the diffusible pigment plasmid has been isolated only as the open‐circular conformation of plasmid DNA and is probably a highly relaxable plasmid. The production of the orange, diffusible pigment was shown to be independent of colony pigmentation.

ISSN:0004-945X    

DOI:10.1038/icb.1985.51

出版商:Nature Publishing Group    

年代:1985

数据来源: WILEY