摘要:

SummaryEosinophils and neutrophils, purified by density gradient centrifugation from the blood of infected mice resistant to reinfection, were tested for their ability to adhere to the different parasitic larval stages of the murine nematode parasiteNematospiroides dubius. Cells were tested for adherence to larvae which had been sensitised with immune mouse serum (IMS) or normal mouse serum (NMS) in the presence of Ca2+and Mg2+ions, EDTA, or EGTA. Differences were observed in the degree of cell adherence to the different stages of the parasite. However, the adherence of the two cell types to any given stage of the parasite was similar. Adherence to the sheathed infective third‐stage (L3) larvae, 96 h post‐infective larvae and to adult worms depended to a large degree on conditions suitable for complement activation (viz. fresh serum and the presence of Ca2+and Mg2+ions). Complement was activated both via the alternative pathway by the parasite itself and via the classical pathway by parasite‐bound antibodies. In these conditions, cell adherence probably occurred predominantly through the interaction of leucocyte third component of complement (C3) receptors with parasite‐bound C3. In contrast, adherence of cells to exsheathed L3 and to the 48 h and 72 h post‐infective larval stages appeared to involve antibody/Fc receptor as well as C3/C3 receptor interaction. The data indicate thatN. dubiusmay undergo a series of antigenic changes during its life cycle and that antibodies capable of mediating granulocyte attachment are elicited predominantly against the early tissue developmental forms of the parasite.

ISSN:0004-945X    

DOI:10.1038/icb.1983.58

出版商:Nature Publishing Group    

年代:1983

数据来源: WILEY

摘要:

SummaryHeat‐treated and untreated sera from rats immune toStrongyloides rattiare capable of arming both immune and non‐immune macrophages and eosinophilsin vitro. These cells are capable of killing larvae of the parasite. Electron microscopy has indicated multi‐point attachment of the cells to the epicuticular transverse grooves of the larvae within 4 and 24 h of incubation at 37°.

ISSN:0004-945X    

DOI:10.1038/icb.1983.59

出版商:Nature Publishing Group    

年代:1983

数据来源: WILEY

摘要:

SummaryActivities of certain acid hydrolases of the spleen were followed in three different rodents during the course ofPlasmodium bergheiinfection. In albino rats where sterile immunity against the infection develops, the specific activities of a few acid hydrolases first declined then increased from day 7 and showed a several‐fold increase over control values when there were no detectable parasites in peripheral circulation. In contrast, inMastomys natalensisand albino mice which succumb to infection the levels of these enzymes were reduced throughout the course of infection. These results indicate a close correlation between host resistance to infection and the level of lysosomal enzymes in spleen.

ISSN:0004-945X    

DOI:10.1038/icb.1983.60

出版商:Nature Publishing Group    

年代:1983

数据来源: WILEY

摘要:

SummaryThe relationships among virus‐specified proteins of Murray Valley encephalitis (MVE), Kunjin (KUN) and West Nile (WN) viruses were investigated by peptide mapping of exhaustive proteolytic digests of radioactively labelled polypeptides. Maps of the three structural proteins (E, C and M) derived from purified virions and of two non‐structural proteins (NV5 and NV4) obtained from infected cells were compared. For each polypeptide considered, the peptide maps of the KUN and WN virus‐specified proteins were more similar to each other than either was to the map of the corresponding MVE virus‐specified protein. Since the polypeptides considered together account for approximately 60% of the coding capacity of the flavivirus genome, our results suggested that, for the three viruses examined, the genomes of KUN and WN viruses are the most closely related.

ISSN:0004-945X    

DOI:10.1038/icb.1983.61

出版商:Nature Publishing Group    

年代:1983

数据来源: WILEY

摘要:

SummaryRufous night herons, Pacific herons, little egrets and intermediate egrets were experimentally infected with Murray Valley encephalitis, Kunjin or Japanese encephalitis viruses. Viraemias of at least one day's duration were detected in all birds except two intermediate egrets inoculated with a very low dose of Kunjin virus and one rufous night heron inoculated with Japanese encephalitis virus. There was usually a viraemia of 3 to 5 days' duration commencing on the first or second day and continuing until day 5 or 6 and rarely until day 7. Maximum titres tended to be higher in young birds, up to 2–5 months of age (104–105mouse LD50/ml), than in older birds more than 8 months of age (103–104mouse LD50/ml). Significant differences in maximum viraemia titres were not observed in the different species or between Murray Valley encephalitis and Kunjin viruses. Japanese encephalitis viraemias were significantly lower, but this was probably due to the high mouse brain passage level of the strain used. The onset of viraemia was earlier in intermediate egrets than in rufous night herons inoculated with similar doses of Murray Valley encephalitis virus, but no difference in the susceptibility to infection was observed. With Kunjin virus there was a significant difference in the susceptibility of intermediate egrets and rufous night herons, with rufous night herons being more susceptible to infection with low doses of virus. This difference in threshold of infection, if it extends to other species with both Kunjin and Murray Valley encephalitis viruses, may, in part, be an explanation for the greater incidence of natural infections observed in rufous night herons compared with other species and orders of water birds.

ISSN:0004-945X    

DOI:10.1038/icb.1983.62

出版商:Nature Publishing Group    

年代:1983

数据来源: WILEY

摘要:

SummaryAntibody responses of rufous night herons (Nycticorax caledonicus) and little egrets (Egretta garzetta) following infection with Murray Valley encephalitis and Kunjin viruses were determined. Haemagglutinin‐inhibiting antibodies were first detected on day 5 or 6 after inoculation and increased rapidly, reaching maximum titres of 320 to 2560 between 10 and 20 days after inoculation. Titres declined to 20–320 between 60 and 120 days after inoculation, then tended to remain stationary. Titres were 2‐ to 8‐fold higher to infecting virus than heterologous virus. Neutralizing antibody development paralleled that of HI antibodies with titres maintained at a higher level for longer periods; however, they did eventually decline to low levels. Following MVE virus infection IgM (19S), HI antibodies were 80–100% of HI antibodies detectable on day 6 or 7 after inoculation and declined rapidly, becoming undetectable by 20 days after inoculation. With Kunjin virus infections, IgM HI antibodies represented 90–100% of HI antibodies detectable on day 6 or 7 after inoculation. Significant levels of IgM HI antibodies were still detectable 20 days after inoculation (5–30% of total HI antibodies) and, in some birds, even at 27 days after inoculation (up to 10%), IgG (7S) HI antibodies were low or undetectable on day 6 or 7 after inoculation, then increased rapidly with rapidly rising HI antibody titres. The specificity of IgM and IgG antibodies and unfractionated sera was determined by testing against Murray Valley encephalitis, Kunjin, Japanese encephalitis and West Nile virus haemagglutinating antigens. It was possible to determine with which virus a bird had been infected from the pattern of cross‐reaction with these antigens. These results should provide a rational basis for the interpretation of serological results from naturally infected birds.

ISSN:0004-945X    

DOI:10.1038/icb.1983.63

出版商:Nature Publishing Group    

年代:1983

数据来源: WILEY

摘要:

SummaryWe attempted to delect and quantify the mechanical effects of change in right atrial pressure on the chronotropic properties of the cardiac pacemaker, when blood volume was altered in an isohaemic fashion by ± 27% in 8 conscious rabbits. Under control conditions there was a strong negative association between heart rate and right atrial pressure, attributable to the baroreceptor‐heart rate reflex. After deletion of the main afferent sources of reflex effects on heart rate, by denervating the arterial baroreceptors and chemoreceptors, there was an insignificant association between heart rate and right atrial pressure or arterial pressure. Then, in addition, the main neurohumoral effects on the cardiac pacemaker were eliminated by three different pharmacologic treatments: (1) the cardiac nerves were blocked by instilling 2% procaine into the pericardial sac, (2) cardiac β‐adrenoceptors and cholinergic receptors were blocked with intravenous propranolol and hyoscine methyl bromide, (3) the above treatments were combined with autonomic ganglion‐blockade by intravenous pentolinium. The combination of cardiac afferent and efferent blockade (1 and 3) revealed a small but consistent positive association between heart rate and right atrial pressure of 1·3 and 0·7 beats/min/mmHg, respectively. With efferent blockade alone (2), there was a steeper positive association of 2·3 beats/min/mmHg. We conclude that in the conscious rabbit there may be a mechanical effect of right atrial pressure on the cardiac pacemaker, but that it is so small as to be of little importance under physiological conditions.

ISSN:0004-945X    

DOI:10.1038/icb.1983.64

出版商:Nature Publishing Group    

年代:1983

数据来源: WILEY

摘要:

SummaryAn enzyme‐linked immunoassay was developed for diagnosing enteric fever. The test measured the inhibition of binding between a labelled, monoclonal IgM antibody and the insolubilized antigen,Salmonella typhilipopolysaccharide (LPS). Good discrimination was seen between 32 proven typhoid cases (88·0 ± 4·4% inhibition) and non‐typhoid cases. The latter consisted of 27 febrile patients bacteriologically and serologically (Widal test) found to be negative for typhoid (26·3 ± 10·8% inhibition), 46 patients screened for syphilis (VDRL test) but found negative (31·2 ± 13·3% inhibition), and 27 healthy blood donors (44·6 ± 13·9% inhibition). The test also efficiently delected all 5 known typhoid carriers (90·6 ± 3·4% inhibition). The antibody binds antigen 9 in the LPS; however, this reaction was inhibited by antibodies directed against both this antigen and an adjacent antigen, 12. Anti‐12 antibodies presumably inhibit by steric hindrance and their importance in the test is discussed. Thus, the assay potentially detects (only) those systemic infections caused by salmonellae that possess antigen 9 or 12 (viz.S. typhiandS. paratyphi A).

ISSN:0004-945X    

DOI:10.1038/icb.1983.65

出版商:Nature Publishing Group    

年代:1983

数据来源: WILEY

摘要:

SummaryPeyer's patch lymphocytes from mice orally primed withV. choleraeinjected into recipient mice together withV. choleraeled to a considerable suppression of IgM antibody‐forming cells in the spleen by comparison with control mice receiving the same schedule but with Peyer's patch lymphocytes from unprimed mice. The effect on the splenic IgA responses of recipients was variable. Incomplete separation of the Peyer's patch cells showed that both T and B cell enriched fractions were active in this suppressive effect.

ISSN:0004-945X    

DOI:10.1038/icb.1983.66

出版商:Nature Publishing Group    

年代:1983

数据来源: WILEY

摘要:

SummaryGlutaraldehyde‐treatedV. cholerasorganisms bind firmly to the surfaces of plastic microELISA plates, thus providing a stable immobilized antigen for use in enzyme‐linked immunosorbent assays (ELISA). Serum absorption and ELISA‐inhibition experiments indicate that, in addition to detecting natural antibodies in normal rat serum, the immobilized antigen may be used to quantitate specific anti‐V. choleraeantibodies induced in rats by injection of live organisms. Apart from serotypically specific anti‐lipopolysaccharide (LPS) antibodies, the reaction with immobilized organisms seems to involve antibodies common to Inaba and Ogawa serotypes; it is suggested that these antibodies are primarily directed against antigens of the outer membrane protein complex ofV. choleraecells. These findings have led to the development of an indirect ELISA method which quantitates levels of antibodies that react with heat‐sensitive surface antigens ofV. choleraewithout involvement of anti‐LPS antibodies. When used in conjunction with the indirect LPS‐ELISA, the test has been found to provide a more detailed description of the serum antibody responses of rats to parenteral injections of liveV. choleraethan has been reported previously.

ISSN:0004-945X    

DOI:10.1038/icb.1983.67

出版商:Nature Publishing Group    

年代:1983

数据来源: WILEY