摘要:

SummaryLymphocytes generated in mice by infection withSalmonella enteritidis11RX release interleukin 2 and macrophage activation factor upon subsequentin vitroculture with bacterial antigens. Lymphokine release requires the co‐culture of non‐adherent sensitized Lyt 1+2‐T cells and adherent metabolically active accessory cells; the interaction between these two populations is restricted by the H‐2I‐A locus. Following systemic immunization with the 11RX strain, the two lymphokines are produced in parallel by peritoneal cells, whereas spleen cells primarily release macrophage activation factor.

ISSN:0004-945X    

DOI:10.1038/icb.1985.53

出版商:Nature Publishing Group    

年代:1985

数据来源: WILEY

摘要:

SummaryAn erythrocyte sialoglycoprotein common antigen has been identified by a monoclonal antibody. The antigen recognised by the JCS‐2 antibody was determined by immunoprecipitation, Western blotting and partial amino acid sequencing. Western blot analysis of human erythrocyte ghost membranes separated on sodium dodecyl sulphate polyacrylamide gel electrophoresis shows that the sialoglycoproteins common antigen occurs on the alpha, beta, gamma and delta sialoglycoproteins, either in their monomeric or dimeric form and as the heterodimer in the case of alpha and delta. TheN‐terminal sequence of the antigen prepared by immunoaffinity chromatography of the Triton‐X100 extract of human erythrocyte ghost shows the first 9 residues to be identical to the known sequence of the MN blood group glycoproteins. The common epitope on the sialoglycoproteins resides on the oligosaccharide and contains sialic acid.

ISSN:0004-945X    

DOI:10.1038/icb.1985.54

出版商:Nature Publishing Group    

年代:1985

数据来源: WILEY

摘要:

SummaryIn this study we have modified a microPlasmodium falciparum in vitrogrowth inhibition assay to allow dissection of growth inhibition induced by test sera into two categories: inhibition of intracellular schizont growth and inhibition of uptake of merozoites into a second cohort of erythrocytes. This was achieved using morphology‐controlled synchronised cultures with incubation times restricted to cover either ring to schizont development or schizont to ring development. Sera tested were obtained from a large prospective study of healthy residents of Madang, Papua New Guinea, who were carefully documented with respect to presence of malarial parasites in the blood, spleen size, age, sex and history of fever. In the ring to schizont assay sera from all the children tested inhibited parasitic growth by at least 20%, compared to only 10 of 39 adults tested (P<0.0005). In the schizont to ring assay 20 of 39 adult sera tested inhibited the uptake of14C‐isoleucine intoP. falciparumprotein compared to 3 of the 15 children's sera tested (P<0.01). These results are interpreted as reflecting a switch from non‐specific mechanisms of resistance with increasing age.

ISSN:0004-945X    

DOI:10.1038/icb.1985.55

出版商:Nature Publishing Group    

年代:1985

数据来源: WILEY

摘要:

SummaryWhenStrongyloides rattifree‐living infective larvae were incubated with peritoneal exudate cells from normal or previously infected mice, cell attachment occurred only in the presence of normal (NMS) or immune mouse serum (IMS). This non‐specific effect was transitory with larvae being alive and free of cells 24 h after incubation. Cell attachment was mediated by complement. When incubated with infective larvae which had penetrated mouse skin, both normal and immune cells attached to larvae in the absence of serum. This effect was again transitory except when immune cells or immune serum were present, indicating a specific immunological mechanism. Again, larvae remained viable. When incubated with isolated parasitic adult worms, persistent cell attachment occurred in the presence of immune serum, immune cells or both, but all worms remained viable. This system provides a means for investigating the mechanisms of resistance to reinfection in strongyloidiasis.

ISSN:0004-945X    

DOI:10.1038/icb.1985.56

出版商:Nature Publishing Group    

年代:1985

数据来源: WILEY

摘要:

SummaryThe role of neutrophils and eosinophils in the acquired resistance of mice to infection with the helminthNematospiroides dubiushas been investigatedin vivoby testing infected mice for their resistance to a challenge dose of larvae following treatment with monoclonal rat antibodies (MAbs) specific for mouse granulocytes. Treatment of normal and infected mice with NIMP‐R10 MAb reduced the number of neutrophils in the peripheral blood and peritoneal cavity during the ensuing 2‐5 days without affecting macrophage or eosinophil levels. The effect of this MAb on immunity depended on the immune status of the mice tested. The partial resistance of mice receiving a primary ‘immunising’ infection, followed by passive transfer of immune serum and challenge at 4 days, was completely suppressed by NIMP‐R10 MAb. The acquired resistance of mice challenged 10 days after being given a single ‘immunising’ infection was halved by NIMP‐R10 treatment, while that of ‘twice‐immunised’ mice (infected on days 0 and 14, challenged on day 24) was unaffected. Treatment of twice‐infected mice with the eosinophil‐specific MAb NIMP‐R6 reduced the number of eosinophils in the blood and peritoneal cavity by 40‐60%, but caused no significant loss of immunity.The data indicate that after infection of mice withN. dubius, neutrophils play a predominant role in early resistance to reinfection, but they become progressively less essential as activated macrophages and (following a second infection) eosinophils become prevalent.The lack of effect of NIMP‐R6 MAb treatment on the immunity of twice‐infected mice may have been due to an insufficient reduction in eosinophil numbers; however, it seems likely that the neutrophils and macrophages present in these mice would have provided adequate protection even in the absence of eosinophils.

ISSN:0004-945X    

DOI:10.1038/icb.1985.57

出版商:Nature Publishing Group    

年代:1985

数据来源: WILEY

摘要:

SummaryIn guinea pigs deprived or ascorbic acid, the oral administration of degradedE. Spinosumcarrageenan induced mild to moderate colitis, whileE. cottoniiconsistently induced severe colitis. A variable degree of colitis was observed in scorbutic animals not receiving carrageenan. By contrast, in animals given large daily supplements of ascorbic acid, neither type of carrageenan consistently induced colitis and seven disease was rarely observed. The severe colitis induced byE. cottoniiin scorbutic animals markedly affected the mid and distal colon and showed histological changes similar to human ulcerative colitis.

ISSN:0004-945X    

DOI:10.1038/icb.1985.58

出版商:Nature Publishing Group    

年代:1985

数据来源: WILEY

摘要:

SummaryAssays of the venom of adult male and female as well as immature funnel‐web spiders (Atrax infensus) were performed both at the end of the winter hibernation period and during the active summer months. For both sexes an increase in venom potency appealed to have occurred with the approach of summer, the venom of adult males then being clearly more potent than that of adult females. However, it was also found that, at least for adult females, forced abstinence from feeding was associated with an increase in venom potency, while feeding (at least on one insect species thatA. infensusis known to accept as prey) seemed to lead to a lowered potency. From these observations it was concluded that the neurotoxin in the venom of female (and presumably also male)A. infensusspiders is probably synthesized in the venom glands rather than being extracted from the prey on whichA. infensusnormally feeds.

ISSN:0004-945X    

DOI:10.1038/icb.1985.59

出版商:Nature Publishing Group    

年代:1985

数据来源: WILEY

摘要:

Summaryα‐Crystallin from human cataractous lenses is so extensively modified that it is unsuitable for structural studies. We have disassembled the protein and, from the remaining traces of unmodified polypeptides, reconstructed a more homogeneous and conformationally discrete molecule. We suggest that this approach may be particularly useful to studies of enzymology and molecular gerontology.

ISSN:0004-945X    

DOI:10.1038/icb.1985.60

出版商:Nature Publishing Group    

年代:1985

数据来源: WILEY

摘要:

SummaryA methicillin‐resistant strain ofStaphylococcus aureus, WG512, was isolated in 1968 and has been shown to harbour a plasmid, pWG14, which encodes the production of a diffusible pigment and resistance to kanamycin, neomycin, streptomycin, lincomycin, erythromyein and spectinomycin. Plasmid pWG14 has only been detected as a slowly migrating band of DNA during agarose‐gel electrophoresis, and this was thought to be the open‐circular form of the plasmid with an estimated molecular weight of 30‐34 Mdal. The transfer properties of this plasmid were compared with a non‐conjugative plasmid encoding tetracycline resistance and the class 2, conjugative plasmid described by Archer and Johnston (1983), Plasmid pWG14 shared many of the conjugative properties of the latter plasmid, including the ability to transfer at high frequency on the surface of a filter membrane and to transfer between non‐lysogenic strains in the absence of Ca++and in the presence of citrate or DNase I. However, unlike the class 2 plasmid, pWG14 was able to transfer in broth culture at low frequency and did not mobilise the non‐conjugative plasmid. Furthermore, the class 2 plasmid and pWG14 were shown to belong to different incompatibility groups. A derivative of WG512, which had lost the ability to produce the diffusible pigment along with plasmid pWG14 but had retained the resistance determinants of plasmid pWG14 in the chromosome, was used to demonstrate that the conjugative mechanism of pWG14 was a property of the plasmid and not the resistance determinants.

ISSN:0004-945X    

DOI:10.1038/icb.1985.61

出版商:Nature Publishing Group    

年代:1985

数据来源: WILEY

摘要:

SummaryRoss River virus was isolated from two out of four seronegative scrum samples obtained from epidemic polyarthritis patients in Australia. Virus isolated from each patient was found to be phenotypically diverse. These isolations suggest that previous failure to isolate virus from epidemic polyarthritis patients in this country may have been due to failure to obtain material (serum) from patients early enough in the course of the disease and to the use of relatively insensitive isolation techniques.

ISSN:0004-945X    

DOI:10.1038/icb.1985.62

出版商:Nature Publishing Group    

年代:1985

数据来源: WILEY