摘要:

SummaryPrior to any exposure to malaria, most adults have T cells specific for malaria parasites and various malaria proteins. The protein for which this has been shown more than any other is the circumsporozoite protein (CSP) of Plasmo‐dium falciparum. These T cells can be present in high frequency and appear to have arisen through exposure to other (non‐malaria) organisms. Although T cells are thought to provide protection against sporozoites, these T cells specific for cross‐reactive organisms are clearly unable to protect against malaria, and may be preferentially expanded following exposure to malaria sporozoites. Thus, cross‐reactive organisms have the potential to skew the repertoire of sporozoite‐induced T cells and affect the induction of protective immunity. This is analogous to the concept of ‘original antigenic sin’ whereby prior exposure to one strain of influenza virus was shown to be able to divert the antibody response to a second challenging strain to focus on the shared (cross‐rea

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1993.tb00599.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SummaryA number of different but complementary approaches have been used to demonstrate the immunogenicity of Necator americanus acetylcholinesterase to infected individuals. Western blotting of parasite somatic extracts with human post‐infection sera and a specific rabbit antiserum to AChE resulted in the development of almost identical antigen‐recognition profiles. AChE‐containing fractions produced by preparative iso‐electric focusing were subsequently shown to be antigenic in ELISA using post‐infection sera. This preliminary data was reinforced by the affinity‐purification of AChE by immobilized post‐infection IgG, and the immunoprecipitation of AChE activity from ES by post‐infection IgG. Finally, AChE purified by affinity chromatography on edrophonium chloride was shown to be antigenic by Western blotting, and in ELISA, against post‐infection sera, although a degree of re‐activity was also seen with normal human sera. This data is discussed in the context of the host‐

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1993.tb00600.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SummaryLevels of sCD23, total and specific IgE were found to be considerably elevated in the plasma of a helminth infected population from Papua New Guinea. Using age‐corrected data, a significant negative correlation was seen between sCD23 and total IgE in the young, at a time when hookworms are being rapidly acquired, and total IgE levels are rising most dramatically. It is suggested on the basis of this data that this inverse correlation is due to the stabilizing effect of IgE on the FceRII receptor in vivo, and that the high levels of sCD23 seen in hookworm infected individuals are partly responsible for the high levels of IgE recorded in these patient

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1993.tb00601.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SummaryWBB6F1 ‐+‐ /+ mice were infested with larval Haemaphysalis longicornis ticks twice at an interval of 14 days: apparent resistance against ticks was expressed in the second infestation. The first infestation induced degranula‐tion of a small number of mast cells at the feeding sites within 6 days, and resulted in two‐fold increases of mast cell numbers on day 14 with a significant elevation of total immunoglobulin E (IgE) levels in sera and high proportion of IgE‐bound mast cells. The second infestation resulted in the intensive degranulation of the increased mast cells at the feeding sites. Eosinophils infiltrated into the feeding sites of ticks: the second infestation led to a greater maximal level of the infiltrating eosinophils. These data suggest that the resistance against larval H. longicornis ticks in mice may be expressed as a result of immediate hypersensitivity and many eosinophils infiltrating from the blood to the feeding sites might contribute to the tick

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1993.tb00602.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SummarySome strains of inbred mice survive acute infection with Trypanosoma cruzi while others die within a few weeks after infection. Mice which express B10 background genes and either the H‐2q or H‐2dhaplotypes are resistant and survive. However, mice which share the B10 genetic background but express H‐2kalleles die, usually within 4 weeks following infection. These data confirm that at least 1 gene in the major histocompatibility complex can determine whether an animal lives or dies during the acute phase. Expression of the H‐2qhaplotype on the B10 genetic background or in DBA/l mice is associated with resistance, but H‐2qmice expressing the C3H background are susceptible. Therefore, at least I gene in the genetic background also influences resistance. Our data suggest that genes associated with resistance must be present in both the MHC and the genetic background or the animal will die. The isotypes and specificities of parasite reactive antibodies found in the serum of different inbred mouse strains were assessed during acute infection. Levels of IgM were higher in sera from mice which express the resistant B10 background than in sera from mice expressing the susceptible C3H background. Conversely, mice which share the C3H background genes produced high levels of anti‐parasite IgG2a when compared to B10 congenic strains. Antigen specificity, however, may be influenced by both background and MHC genes, as congenic strains expressing different MHC haplotypes recognized different constellations of T. cruzi antigens. These data suggest a correlation between genes which influence antibody specificity or isotype and the genes which determine the ability of various inbred mouse strains to survive acute infection wi

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1993.tb00603.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SummaryThe lytic effect of complement activated through the alternative pathway (AP) was studied on pathogenic and nonpathogenic Entamoeba histolytica recently isolated from stool samples. Recent nonpathogenic isolates were nearly unaffected by exposure to AP whereas recent pathogenic stool isolates were highly susceptible to AP dependent complement‐mediated lysis. Complement susceptible pathogenic stool isolates developed complement resistance in vivo during hamster liver passage and in vitro during cultivation in the presence of increasing concentrations of normal human serum (NHS). Since a clone of pathogenic HM‐l.IMSS which initially was highly susceptible also acquired complement resistance during cultivation in the presence of NHS, it is concluded that complement resistance was caused by induction rather than by selection alone. Because cultivation in the presence of heat‐inactivated NHS did not affect complement susceptibility of the cloned HM‐l.IMSS, complement activation itself might induce complement resistance in pathogenic E. hist

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1993.tb00604.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SummaryP. falciparum merozoite antigens, merozoite surface protein‐l (MSP‐1) and rhoptry associated protein‐1 (RAP‐1), were shown to be liberated into the supernatant of in vitro parasite cultures and to be included in the endotoxin‐like exoantigen complex, previously designated Ag7. Material affinity purified from culture supernatants, using immobilized monoclonal antibodies specific for RAP‐1 or MSP‐1, stimulated normal human mononuclear cells to produce TNF and IL‐6 in vitro. However, stimulation of TNF was absent, and that of IL‐6 was reduced, when the antigens were purified from detergent extracts of infected erythro‐cytes. These results indicate that the RAP‐1 and MSP‐1 proteins themselves do not stimulate the production of TNF. Instead, other components associating with these exoantigens may be responsible for the TNF production. Mouse antisera blocking TNF production stimulated by P. yoelii exoantigens also blocked TNF production stimulated by material affinity purified from P. falciparum culture supernatants using RAP‐1 specific monoclonal antibody, indicating the conserved structure of t

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1993.tb00605.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SummaryTwo synthetic polypeptides containing multiple B‐ and T‐cell epitopes derived from the conserved regions of two vaccine candidate antigens namely MSA‐1 and RESA of human malarial parasite P. falciparum were studied for immunogenicity and protectivity. Both constructs elicited strong antibody and lymphocyte proliferation responses in BALB/c mice immunized with the carrier‐free peptides. In an ELISA, these peptides also bound antibodies present in the sera from the P. vivax infected humans as well as from the P. yoelii infected mice. Significantly, our data showed that immunization of mice with these P. falciparum peptide could impart partial protection against P. yoelii challenge infection. Our finding that synthetic peptides representing portions of P. falciparum antigens were capable of stimulating protective immune responses against rodent malaria suggests that murine malaria model P. yoelii may provide a suitable system for primary screening of potentially protective synthetic imm

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1993.tb00606.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY