摘要:

Summary125I‐labelled proteins associated with the surface of the oncosphere and metacestode stages ofTaenia pisiformiswere investigated, together with the presence of host immunoglobulin G on the parasite surface. Rabbit IgG was detected by enzyme‐linked immunosorbent assay (ELISA) in the acid washes (pH 3.0) of viable 3‐week migratory metacestodes and 8‐week mature cystic metacestodes from the liver and peritoneal cavity, respectively, of rabbits orally infected with eggs ofT. pisiformis.However, specific anti‐T. pisiformisIgG antibodies could not be detected in these washes using ELISA. When intact and washed hatch‐activated oncospheres and 3‐week and 8‐week metacestode stages were iodinated with Bolton‐Hunter125reagent and examined by SDS‐PAGE and autoradiography, there appeared to be a marked loss and/or reduction of labelled proteins on the mature cystic metacestode compared to the oncosphere and 3‐week juvenile metacestode stages. Six‐week post‐infection rabbit sera strongly immunoprecipitated a 43 kD iodinated protein from oncospheres together with others including a 65 kD polypeptide. Only the 65 kD polypeptide, which is the major iodinated protein on 3‐week liver metacestodes, was immunoprecipitated from these juvenile or the mature metacestode stages. The results are discussed in relation to survival of metacestodes in the host, and as to how acquired resistance might result from both frequent egg challen

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1988.tb00218.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

SummaryThe possible existence of stage‐specific immune responses toTaenia Taeniaeformisinfection was investigated in C3H/He mice vaccinated with antigens prepared from either the oncosphere or metacestode stages. Mice were immunized twice, 2 weeks apart, with antigen in Freund'B complete adjuvant. Two weeks after the second immunization they were challenged with 250T. Taeniaeformiseggs and killed day 0, 5, 10, 15, 20, 25, 30, 45 and 60 after infection. Gross examination of the livers revealed marked differences between oncosphere (TtO) and metacestode (TtM) vaccinated mice. Very few metacestodes were found in the first group but most of those that evaded the initial host attack developed like the cysts found in the control group. In contrast, many degenerating metacestodes were found in the TtM vaccinated group. In a subsequent experiment groups of mice were vaccinated with varying doses of either TtO or TtM to determine whether the qualitative differences observed above were due to antigen dose effects. However, varying antigen doses gave the same results. These data show that vaccination with oncospheres generates an immune response capable of killing invading larvae soon after infection whereas vaccination with TtM results in larvae being killed at a later stage, suggesting that there are stage‐specific, host‐protective ant

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1988.tb00219.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

SummarySerum antibody responses in two strains of mice infected with embryonated eggs ofHymenolepis nanawere analysed by the enzyme‐linked immunosorbent assay (ELISA) and immunoprecipitation (TP) using sodium deoxycholate (DOC)‐solubilized antigens prepared from embryonaled eggs (eggs), mouse‐derived cysticercoids (cysts) and adult tapeworms with immature segments only (adults). Highly susceptible dd mice, which harbour mature tapeworms for a long period (>70 days), produced high levels of antibodies to all three different stages ofH. nana.BALB/c mice, almost all of which expel adult tapeworms by 30 days after infection, produced high levels of antibody against egg antigens only. The high antibody titres to cyst and adult antigens in dd mice did not lead to expulsion of the worms. However, worms are rejecled early in BALB/c mice when there is little or no detectable serum antibody. The antibody responses to eggs seen in BALB/c mice which had long since shed their adult worms were probably due to ingestion of eggs from faeces of other infected mice. Antibodies to eggs were not detected in BALB/c mice which were initially inoculated with eggs (day 0) and then treated with praziquantel on day 6 after the tissue phase of infection only. The different antibody responses to egg antigens and the other two antigens (cyst and adult) in BALB/c mice suggest a difference in antigen specificity between eggs and both cysts and adults. A major antigen component with Mt 32 000 appears to be specific to the egg (or oncosphere) stage ofH. nana.Antibody to this major component of eggs was absorbed only with intact eggs, but not with intact cysts nor adults with immature segments only, so that the antigen appears to be on the surface of the oncos

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1988.tb00220.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

SummaryCross‐reactivity was demonstrated between circulating antibodies fromTrichuris trichiura‐infected humans and T.muris‐infected mice for heterologous antigen preparations. Mouse immune sera raised against excretory/secretory (E/S) products and anterior end homogenate from adultT. murisshowed marked affinity forT. trichiuraadult homogenate in ELISA, and35S‐methionine‐labelled adultT. murisE/S products were precipitated byT. trichiurainfection sera. Monoclonal antibodies recognizing a 48 kDTrichinella spiralismuscle larval β‐stichocyte granule antigen also showed avidity forT. trichiuraadult homogenate in ELISA, as did scrum from mice with patentT. murisworm burdens. This cross‐reactivity is thought to result from shared stichocyte antigens and the relevance of this observatio

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1988.tb00221.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

SummaryThe antibody‐dependent cell‐mediated larvicidal response of AO rats againstTrichinella spiralisnewborn larvae was studiedin vivo.Rats were immunized with 2000‐3000 muscle larvae orally and then challenged 6‐20 days later with 10 000‐20 000 newborn larvae intraperitoneally. Newborn larvae recovery from the peritoneal cavity decreased significantly and was accompanied by cuticular cell adherence and killing of newborn larvae by day 9 of infection. Similar effects were observed when newborn larvae were incubated with blood obtained from immunized rats. The cell adherence and larvicidal responses reached their peak by day 16 of the primary infection. Passive transfer experiments demonstrated that newborn larvae infectivity was substantially impaired once cell adherence occurred. Culicular adherence took placein vitroonly when immune serum was added to the incubation medium. Complete destruction of newborn larvaein vivoafter passive transfer, as measured by muscle larvae burden was only evident after exposure to both immune serum and immune cells, not to either alone. Non‐specific stimulation of the peritoneal cavity with a sterile intestinal infection failed to induce cuticular adherence or larval killing in these rats. We conclude that a stage‐specific antibody‐dependent cell‐mediated larvicidal response is rapidly generatedin vivoafter the host is exposed to newborn larvae. It is a systemic response which impairs the infectivity of newborn larvae and can destroy them before they re

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1988.tb00222.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

SummaryThe model ofOnchocerca lienalismicrofilariae (mf) in CBA mice has been employed to examine the immunological mechanisms underlying the destruction of skin‐dwelling mf in onchocerciasis. Comparative studies among tmmunologically intact (CBA/H) or deficient (CBA/N, T‐cell‐deprived) syngeneic animals demonstrated that levels of mf of a primary infection were reduced most rapidly in fully immunocompetent mice. Significant reductions in recoveries of a secondary infection were evident in CBA/H (80%) and CBA/N (44%) mice, but not in T‐cell‐deprived animals. The establishment of primary and secondary infections was apparently not influenced by complement, as judged by C3 depletion with Cobra Venom Factor. Eosinophilia was demonstrated to varying degrees in all infected animals; similar levels occurred in CBA/H and CBA/N mice which were greatly elevated after mf challenge. In contrast, the eosinophil response of T‐cell‐deprived mice was weak and not potentiated during secondary infection. Type I immediate hypersensitivity responses to soluble mf antigen (mf‐Ag) were mounted by all groups, but significantly less strongly in T‐cell‐deprived mice. Type IV delayed responses were generally weak, although CBA/N mice reacted strongly in the early phase of primary infections. During the first 2 weeks of infection CBA/H and T‐cell‐deprived mice mounted rapid IgM responses to mf‐Ag. Subsequently, levels of IgG2a, IgG2b and IgGI increased in all mice. There was a potentiated IgG2a, IgG2b and IgG I response in all groups following challenge, with levels of IgGJ highest in CBA/H mice. IgE responses were also detected by passive cutaneous anaphylaxis during primary and secondary infections. Peak levels of parasite‐specific antibodies coincided with

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1988.tb00223.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

SummaryThe diagnosis of human infection byToxocara canisrelies heavily upon serological tests, the specificity of which can be inadequate in regions of endemic helminthiasis. When different population groups of tropical Venezuela were evaluated using ELISA based uponToxocaraexcretory‐secretory antigen (TcES A), solid‐phase adsorption of the sera with extracts of a wide variety of non‐homologous parasites revealed the existence of significant cross‐reactivity. This was effectively and conveniently overcome when the test sera were incubated in the presence of the soluble parasite extracts in a competitive inhibition ELISA. The mean reduction of ELISA values caused by pre‐adsorption of the sera tested was 32‐2%, and that caused by competitive inhibition was 42‐3%, the effects of these two procedures being strongly correlated (r=0.83). The magnitude of the reduction was inversely proportional to the actual ELISA value (r=‐0.55), and ranged from a mean of 68.0% in sera from apparently healthy individuals of medium‐high socio‐economic level, down to 28.1% in heavily parasitized Amazon Indians.Ascarisshowed the greatest degree of cross‐reactivity in these tests, although under conditions of competitive inhibition even sera with high levels of antibody against this parasite could be negative inToxocaraELISA. Western blotting revealed a major 81 400 D component that was shared betweenAscarisand TcESA.Our results indicate that the competitive inhibition of cross‐reactivity by soluble non‐homologous parasite extracts provides a convenient and economical means of increasing the specificity of ELISA for the determination of the seroprevalence of toxocariasi

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1988.tb00224.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

SummaryThe liver mcrozoites of malaria parasites arc of paramount importance, as they initiate the parasite invasion of red blood cells and start the cycle associated with the clinical features of malaria. Investigating liver merozoite antigen is difficult because of the lack of a rodent model of human malaria. In addition, only a low proportion of cells are obtainedin vivo, the parasites fromCebusandAotusmonkeys are immature, and in‐vitro experiments with liver cells are often confounded by contamination with the natural mosquito flora co‐purified with the sporozoites used for seeding the liver cultures.In our study, mature liver schizonts were shown to possess many of the antigenic determinants recognized by MoAbs and sera specific for defined sporozoite and blood‐stage antigens. We employed an immunofluorescence procedure based on evaluating parasites in cryosections prepared from infected chimpanzee liver. Sufficient numbers of sectioned parasites were evaluated with each antibody to assure the reproducibility of the results, and the fixation procedure used was sufficiently non‐destructive to parasite antigens so that clear differences between reactions of specific antibodies and negative controls were observed.Our evidence for sharing of epitopes by liver merozoites and sporozoites or by liver merozoites and asexual blood‐stage parasites raises the possibility that immune responses elicited against sporozoites or asexual stage antigens being considered as vaccine candidates may also act against this important, little‐studied stage of t

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1988.tb00225.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY