摘要:

SummaryCytotoxic effects of mouse cells onPlasmodium yoeliiwere sought directly by incubating parasitized red cells with cells of various kinds for 16 h and then determining the percentage parasite survivalin vivo, in terms of infectivity for the mouse. Cell populations rich in lymphocytes, e. g. lymph node and spleen, were less active than peritoneal cells and blood. Parasite killing by peritoneal cells was associated with macrophages: treatment with anti‐macrophage serum (AMS) or depletion by adherence or centrifugation on Ficoll decreased activity. Polymorphonuclear leucocytes (PMN) in induced exudates may have contributed to killing, although not as actively cell for cell, and an effect of eosinophils in worm‐induced exudates was not excluded. White blood cells were most active of all and fractionation on Ficoll confirmed that lymphocytes were relatively ineffective. The effector cell was phagocytic but it was insensitive to AMS. Tests on populations with high or low proportions of PMN showed that parasite killing was independent of PMN number. It is concluded that the effector cell belongs to the monocyte‐macrophage series and has acquired the ability to kill the parasite before becoming fully differentiated into a macro

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1982.tb00421.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

SummaryPretreatment of mice with BCG induced a high level of protection against infection withTaenia taeniaeformis.Protection was manifested both during and after establishment by the parasite suggesting that two separate mechanisms were stimulated by BCG. The first inhibits initial establishment by the parasite and may be antibody mediated. The second is responsible for the destruction of developing strobilocerci in the liver and may require the involvement of cellular defence mechanisms.

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1982.tb00422.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

SummaryCercariae, skin stage schistosomula, and lung stage schistosomula ofSchistosoma mansoniwere attenuated by gamma irradiation and tested for their ability to induce protective immunity against cercarial challenge in C57B1/6J mice. The highest levels of resistance were induced by cercariae administered either percutaneously or intramuscularly. Skin stage schistosomula inoculated intramuscularly gave less protection while lung stage schistosomula from syngeneic donors were the least immunogenic. A similar ranking in immunogenicity was observed when the anti‐skin stage schistosomular antibody responses induced by the different parasite stages were compared. In contrast, none of the immunization protocols were found to stimulate antibodies capable of recognizing lung stage schistosomula. These results suggest that, as schistosome larvae mature from the cercarial to the lung stage, they undergo a substantial loss in immunogenicity. This change may help explain the failure of older larvae to be immunologically destroyed in infected host

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1982.tb00423.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

SummaryGlycoproteins fromTrypanosoma cruziepimastigotes have been extracted by diiodosalycilic acid and lithium salts, and phenol‐water biphasic partition. Peanut agglutinin has been used in a one step preparative method for fractionating the total extract in order to separate the so‐called galactose‐terminal glycoproteins. The different fractions have been studied by SDS electrophoresis, ultracentrifugation and immunoelectrophoresis techniques. The experimental immunogenicity, antigenicity and specificity of the PNA affinity fractions has been eval

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1982.tb00424.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

SummaryIt was possible to block the transmission of infection of the rodent malaria parasitePlasmodium yoelii nigeriensistoAnopheles stephensimosquitoes by immunizing mice with a vaccine containing formalin‐fixed gametes. Both intramuscular and intravenous routes were effective, immunity was achieved with a single dose and the immunity persisted for 6 months at least. Transmission‐blocking immunity was found to reside in a serum factor, probably antibody, and to be directed against extracellular gametes, acting on them in the gut of the mosquito, while gametocytes in the circulation of the vertebrate host remained unaffected. The gamete vaccine afforded partial protection against the disease, but immunization with asexual parasites alone showed that this protection was due largely to the presence of asexual forms as contaminants and that anti‐gamete immunity is stage spe

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1982.tb00425.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

SummarySchistosomes grown in mice were tested at different stages of development for susceptibility to anin vitrocytotoxic effector mechanism involving eosinophils and an antibody directed against mouse determinants. Despite the fact that 5‐day lung worms and 6‐week adult worms both bound the antibody to their surfaces, eosinophils attached preferentially to the adults and killed them. Complement had an enhancing effect in this system. Those eosinophils which did adhere to the lung worms degranulated onto the tegument but were unable to mediate damage or killing, even when complement was activated at the parasite surface. The resistance shown by the lung worms was shared by 2‐week worms and small 3‐week worms. Larger 3‐week worms and older stages were, however, susceptible to cell‐mediated cytotoxicity in this system. We suggest that the host antigen disguise constitutes the major protective mechanism utilized by older schistosomes to evade immunity, but that the younger stages have an additional and equally effective mechanism of

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1982.tb00426.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY