摘要:

SummaryLive attenuated strains of salmonellae are showing promise as live oral vaccines against human typhoid fever and otherSalmonellainfections of man and animals. Attenuation can be achieved by introducing genetically defined, non‐reverting mutations into specific genes on theSalmonellachromosome. Mutations in thegalE oraroA genes ofSalmonellainhibit the ability of the bacteria to growin vivo, and strains carrying such lesions are effective vaccines against salmonellosis. Genetic determinants encoding for the expression of potentially protective antigens from heterologous, non‐Salmonellapathogens can be readily introduced into these attenuatedSalmonellastrains. Expression of the heterologous antigen does not affect the ability of theSalmonellahost to be used as aSalmonellavaccine. Mice infected orally with aSalmonella typhimurium aroA vaccine expressing theEscherichia coliheat‐labile toxin B subunit developed both a secretory and serum antibody response to this antigen. These serum antibodies were able to neutralise the activity ofE. coliheat‐labile toxin in tissue culture assays. A humoral and cell‐mediated (DTH) immune response was detected against beta galactosidase, an intracellular antigen, in mice infected with anaroA vaccine expressing this cloned antigen. The prospects for the development of liveSalmonellavaccines as a method for delivering heterologous antigens derived from bacteria, viruses and parasites is

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1987.tb00496.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryMice with self‐limitingP. yoeliior fatalP. bergheiinfections exhibited a markedly impaired ability to mount specific splenic cytotoxic T‐lymphocyte responses to immunization with infectious ectromelia (EV), vaccinia (VAC), or lymphocytic choriomeningitis viruses (LCMV). Lymph node responsiveness, however, was not impaired. Primary CTL responses were depressed in mice immunized 7 days afterP. bergheiinfection, while inP. yoelii‐infected mice, depressed responses were detected only during the period corresponding with maximal parasitemia (days 9–12). Secondary VAC‐specific CTL responsesin vitroby spleen cells of mice previously immunized duringP. yoeliiinfection were also depressed if UV‐inactivated rather than infectious VAC was used for immunization. In addition, spleen cells of mice already immune to VAC failed to yield normal secondary CTL responsesin vitroduring the period of maximalP. yoeliiparasitaemia. Collectively, these findings indicate that, during patent malaria infections, priming for and expression of virus‐specific CTL responses may

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1987.tb00497.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryThe mouse macrophage cell line J774 was easily infected byT. cruziepimastigotes which were transformed to amastigotes that multipled inside the cells. Spleen‐T‐cells fromT. cruziimmune mice stimulated with Concanavalin A orT. cruzi, but not with unrelated antigens, released lymphokines into the supernatants that when added to J774 cells were unable to induce complete trypanocidal activity, although they were able to delay the rate of infection by protecting the cells from being infected. Addition of bacterial lipopolysacharide (LPS), although inactive by itself, acted synergistically with the supernatants in inducing complete trypanocidal activity without affecting the susceptibility of J774 cells to infection. Gamma‐interferon (γ‐IFN) activity was detected in the supernatants, however, but was not solely responsible for the trypanocidal inducing activities, since: (1) there was no correlation between the levels of γ‐IFN and macrophage activation; (2) γ‐IFN alone was less effective than the supernatants alone; and (3) two active fractions of 100 000–150 000 mol. wt and 30 000 mol. wt were separated by gel filtration chromatography of the lymphokine preparations. The latter, which showed the characteristics of γ‐IFN with respect to size, pH 2 sensitivity and antiviral activity, had some trypanocidal activity alone. However, the 100 000–150 000 mol. wt fraction was active only in the presence of LPS. Finally, this trypanocidal inducing activity of the supernatants was not due to the induction of synthesis of γ

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1987.tb00498.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryMice exposed to primary infections with the parasitic intestinal nematodeNematospiroides dubiusfailed to show the mucosal mast cell (MMC) response which is characteristic of infections with other species of intestinal nematode and which was readily induced in these mice by infections withNippostrongylus brasiliensisorTrichinella spiralis.The failure to generate a mucosal mastocytosis was independent of host strain or sex. When infections withN. dubiuswere established before, or concurrently with,T. spiralisorN. brasiliensis, the MMC response elicited by these species was delayed and/or depressed as was expulsion of the worms themselves. Infection withN. dubiusgiven when a MMC response was already established, by exposure toT. spiralis, had no effect on MMC numbers. The possibility that the effects ofN. dubiusupon MMC responses reflect a lack of mastocytopoietic potential, rather than an active interference, was excluded by showing that SJL mice, which expel primary infections withN. dubiusand express strong immunity to reinfection, developed marked mastocytosis during secondary infections. The depression of MMC responses byN. dubiusis discussed in relation to the known immunosuppressive properties of this parasite and in relation to the T cell mediated control of MMC development.

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1987.tb00499.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryTaeniaestatin, a recently isolatedTaenia taeniaeformisproteinase inhibitor, was used to inhibit equine neutrophil migration. Taeniaestatin itself was not chemotactic when used as a chemotactic factor but taeniaestatin did inhibit neutrophil chemokinesis when tested in a Zigmond‐Hirsch checkerboard assay. A dose‐dependent inhibition of both chemokinesis and chemotaxis was observed when zymosan activated bovine sera (ZABS) was used as the chemotactic factor. This inhibition was>95% when 5 u of taeniaestatin was present on both the cell and chemotactic factor side of the chambers. Equine neutrophils gave dose‐ and time‐dependent migration responses to purified bovine C5a with an ED50of 1±04 ± 10–7M. Taeniaestatin inhibited the C5a‐mediated chemotactic and chemokinetic neutrophil responses (51% using 1 u and>95% with 5 u of taeniaestatin). The inhibition of leucocyte motility by taeniaestatin was reversible and without cytotoxicity at the highest doses of taeniae

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1987.tb00500.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryGuinea‐pigs made T‐cell deficient by thymectomy and irradiation, and protected with syngeneic bone marrow cells (TXB) have a greatly reduced capacity to express normal cell‐mediated immune functions, based on their poor responses to T‐cell mitogens, prolonged acceptance of skin allografts, and susceptibility to the lethal effects of graft‐versus‐host disease. Further evidence for impaired T‐cell activity in TXB guinea pigs was based on their inability to be fully sensitized to mycobacterial antigens, and increased susceptibility to an intradermally induced infection with the intracellular protozoan parasite,Toxoplasma gondii(RH strain). After challenge at multiple sites with 106or 105parasites, toxoplasmosis in thymus‐intact, fully immunocompetent guinea pigs is a self‐limiting and survivable infection, whereas the disease takes an acutely lethal course in the majority of TXB guinea‐pigs. The latter also had more parasites disseminating to various tissues sites than their euthymic counterparts. The reduced capacity of TXB guinea‐pigs to respond to mycobacterial products, and to generate anti‐Toxoplasmaimmunity can be restored by an intravenous infusion of normal syngeneic thymocytes. These findings provide substantial direct evidence strengthening the concept that protection against toxoplasmosis is heavily dependent upon an intact T‐cell component of t

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1987.tb00501.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummarySummaryThe accumulated andde novosynthesized antigens expressed by L3, L4 and adultNecator americanus. recognized by both the natural host, man, and the experimental host, the hamster, were identified by immunoblotting and immunoprecipitation analysis. Following infection of neonatal hamsters serum samples were taken on days 17, 35 and 117. Only serum taken 117 days after infection showed significant reactivity in immunoblotting experiments, recognizing adult epitopes of 30000, 33000, 48000 and 69000 mol. wt thereby suggesting that few accumulated antigens are shared between developmental stages. By contrast, immunoprecipitation analysis of metabolically labelled proteins suggested that L3 and in particular L4 larvae synthesize some antigens which comigrate with those synthesized and accumulated by adult worms. In addition, L4 larvae synthesize a 41000 mol. wt excretory/secretory (ES) stage specific antigen.Parallel experiments using serum samples from infected humans, demonstrated that hamsters and man recognize many antigens of identical molecular weight. Notable in this respect are accumulated adult antigens of 30000, 33000, 48000 and 69000 andde novosynthesized antigens of 30000, 33000, 44000, 46000 and 69000 mol. wt. Some individual human sera mainly recognized L3 antigens of 47000–69000 mol. wt in immunoblotting experiments whilst others simultaneously recognized adult epitopes. This differential recognition of developmental stages by individual human sera suggests that genetic or epidemiological factors are operative and warrants further study.Overall, these studies confirm the pronounced immunogenicity ofNecator americanusin both man and an animal model and pave the way for analysis of the relevance of these antigens to field situation

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1987.tb00502.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryThe interaction of the mouse complement system with adult maleSchistosoma mansoniwas studied by immunocytochemical localization procedures and in‐vitro assays for complement mediated tegument damage. Mouse C3 was demonstrated to be associated with the parasite's tegument, but was localized only in the infoldings of the tegument and not on its free surface. Freshly harvested parasites manifested no detectable tegumental modification when incubated in normal mouse serum or in immune mouse serum. However, parasites which had been allowed to lose their adsorbed host components by elution (incubation in serum free media for 3 h at 37°C) were severely damaged by incubation in normal mouse serum, but not by incubation in immune mouse serum. This damage was shown to be mediated by the alternative complement pathway and appeared to be initially limited to the tubercles of the adult male parasite. Tegument disruption could be blocked by pre‐incubation of the eluted worms in either immune mouse serum or an IgG fraction of immune mouse serum. An IgG fraction of normal mouse serum did not protect the parasite, and infected mouse serum (IMS) which had been depleted of IgG produced tegument damage equivalent to that observed with normal mouse serum (NMS). The addition of I‐IgG to NMS abrogated tegument damage. These data suggest that while adult schistosomes possess surface molecules bearing alternative pathway complement activation sites, these sites are masked by adsorbed host componentsin vivo.These results further indicate that in the absence of these masking host molecules anti‐schistosome IgG may play a role in protecting the adult worm from alternative pathway activation, perhaps by binding to and blocking the activation sites on the tegument associated m

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1987.tb00503.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

SummaryClinical and experimental studies indicate that following invasive disease due toEntamoeba histolytica, development of human cell‐mediated immune mechanisms may provide protective immunity. Activated, human monocyte‐derived macrophagesin vitrocan kill virulent axaenic amoebic trophozoites. This study describes the interaction of lectin‐stimulated T‐lymphocytes andE. histolyticatrophozoites (virulent strain HM1‐IMSS). Amoebae progressively killed unstimulated nonimmune T‐lymphocytes over 18 h incubation with no effect on amoebic viability. T‐lymphocytes, stimulated with phytohaemagglutinin (PHA), were progressively cytotoxic for virulent HMI amoebae over 18 h incubation, but were also reduced in viability themselves. Lymphocyte cytotoxicity for amoebae was absent if PHA was removed before or added only during the assay. PHA‐stimulated T‐lymphocytes killed amoebae at cell ratios of lymphocytes to amoebae as low as 50:1 and cytotoxicity was antibody‐independent. PHA‐stimulated T‐lymphocytes, depleted of T8‐bearing cells by complement‐mediated lysis, were unable to kill amoebae. Adherence of PHA‐stimulated T‐lymphocytes to amoebae was greater than with unstimulated T‐lymphocytes. Inhibition of the amoebic adherence lectin withN‐acetyl‐D‐galactosamine decreased lymphocyte‐amoebic adherence and resulted in increased lymphocyte amoebicidal activity and lymphocyte survival. Suspension of amoebae with or without adherent PHA‐stimulated T‐lymphocytes in a 10% dextran solution indicated that cytotoxicity was contact dependent. In summary, PHA‐stimulated T‐lymphocytes of the T8‐phenotype can kill virulent axaenicE. histolyticatrophozoites through

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1987.tb00504.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1987.tb00505.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY