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1.
Dobson C. and Cayzer C. J. R. 1982. Passive transfer of immunity with serum in mice infected with Nematospiroides dubius: in vitro effect of immune serum on larval infectivity. International Journal for Parasitology12: 413–421. Incubation of Nematospiroides dubius larvae in serum in vitro induced 15% exsheathment after 3h. Larvae incubated in immune mouse serum at 37°C for 3h lost 20% of their infectivity for mice. Immune serum from donors given 1–7 concurrent or anthelmintic abbreviated infections all depressed larval infectivity to the same extent. Larvae incubated in immune sera were protected from the effects of passively transferred immune serum in mice following infection. The effects of incubation of larvae in immune serum were prolonged into the adult stages of the parasite and were seen as stunting of worms and a reduction in the male-female sex ratio of the parasites.  相似文献   

2.
Intraperitoneally implanted metacestodes of either T. taeniaeformis or T. crassiceps in rats provoked a high degree of resistance to oral challenge with eggs of T. taeniaeformis. This resistance was passively transferred to normal recipients with serum. Immunoglobulin fractions of immune serum containing IgG1 or IgM were most effective in passive transfer and little activity was associated with IgG2 antibodies. No skin-sensitizing antibodies were detectable in immune sera. These findings are in sharp contrast to previous observations involving protective immunoglobulins and reaginic antibodies in serum from rats with hepatic cysticerci of T. taeniaeformis. Possible reasons for this are discussed. Cysticerci implanted into normal rats survived for at least 21 days with no sign of host rejection, whereas those implanted into rats with hepatic infections with T. taeniaeformis were killed and encapsulated. Similar results were obtained by implanting cysticerci in normal rats given inoculations of complete Freund's adjuvant. Repeated inoculations of immune serum had no effect on the survival of implanted cysticerci, and it was concluded that exposure to infection by oncospheres provokes cellular defense mechanisms which can be effective against cysticerci in abnormal sites. Why these mechanisms are inoperative against hepatic cysticerci remains unclear.  相似文献   

3.
Antigen preparations of Plasmodium chabaudi parasites enriched in merozoites and schizonts, obtained from in vitro culture, and combined with saponin protected C57BL/6J mice from P. chabaudi infection as judged by reduced primary parasitemias and recrudescences. Sera passively transferred from immunized and untreated mice after a challenge infection were more protective in recipients than serum from normal mice. Mice treated with antilymphocyte serum during immunization did not develop as strong an immunity to infection as did controls treated with normal serum. Immunized mice had depressed delayed-type hypersensitivity reactions to malarial antigen but increased serum titers of malarial antibody (measured by imniunofluorescence) after challenge with P. chabaudi when compared to immunized mice which remained unchallenged. The protective activity of sera from various groups of mice did not necessarily correlate with the serum antibody titers.  相似文献   

4.
Significant protection against infection with 10 or 30 metacercariae of Fasciola hepatica was conferred on naive rats by the passive transfer of serum derived from rats which had been exposed to primary and challenge infections with 5 or 10 and 30 or 20 metacercariae respectively. Immune serum did not have a pronounced effect on the mortality of metacercariae in vitro. However, its presence was associated with the formation of a precipitate on the tegument of each metacercaria and in the culture medium. The precipitate contained rat antibody and other components, presumably parasite antigens, which elicited the formation of antibody when the precipitate was injected into rats. Viability of metacercariae cultured in immune and normal sera as well as freshly excysted specimens was tested in rats by intraperitoneal infection. Metacercariae cultured in immune serum did not develop. By comparison with the viability of freshly excysted metacercariae, that of some metacercariae cultured in normal serum was impaired; this was attributed to inadequacies in the culture technique. A relationship between precipitate formation in vitro and impaired viability of metacercariae in vivo has yet to be established.  相似文献   

5.
-Yong W. K. and Dobson C. 1982. The passive transfer of proctective immunity against Angiostrongylus cantonensis with immune lymph node cells from different lymphoid tissues in rats. International Journal for Parasitology12: 423–425. Lymph node cells from the posterior cervical and mesenteric lymph nodes of immune rats passively protected syngeneic recipient rats against Angiostrongylus cantonensis better than cells from the spleen, thymic and inguinal lymph nodes either as reduced worms burdens and/or stunted growth. No antibody was detected in the sera of recipient rats after transfer of the cells and before infection which suggested that the protection was cell- rather than antibody-mediated.  相似文献   

6.
A protective immunity against the cestode Hymenolepis nana was transferred with serum taken from actively immunized mice. All of 17 pooled sera examined, which were taken from mice immunized for 3 or more weeks, were strongly effective. Intraperitoneal injection of a total of 3·0 ml serum made the recipient mice (4–5 weeks old) almost completely immune. In almost all the mice given immune serum no cysticercoids were found on day 4. In mice receiving immune serum, oncospheres hatched, invaded the intestinal villi and differentiated to stage II or III larvae, but failed to develop to fully developed cysticercoids. The degree of protection conferred by serum transfer was similar to, but slightly weaker than that stimulated by active immunization. The major effect of immune serum was damaging hatched oncospheres in both the intestinal lumen and the villi within 1 day post infection.  相似文献   

7.
An original protocol of cell transfer from Schistosoma mansoni-infected rats to normal recipient rats is used to investigate the protective role of phagocytic cell populations, described as effector cells in vitro, against a challenge infection with S. mansoni. Nonadherent, eosinophil-enriched and -adherent, macrophage-rich cell preparations, injected via intradermal and subcutaneous routes at the precise site of exposure to cercariae, were able to significantly protect the recipient rats. The time-course study of this protective effect according to the time after infection of donor rats revealed that eosinophils were the major cell population involved in the early phase of infection (4 to 5 weeks), whereas macrophages could also be incriminated thereafter. A rosette assay using anti-immunoglobulin-coated erythrocytes indicated a sequence of the various antibody isotypes under study (IgG1, IgG2a, IgE) on the eosinophil surface, during the course of infection. As previously shown in vitro, cytophilic antibodies seemed to participate in the protective effect of eosinophils, since eosinophil-enriched cells from normal rats, sensitized in vitro with immune complexes present in infected rat serum, could also confer significant protection. These observations establish therefore the relevance between our previous in vitro studies and rat resistance to a challenge infection with S. mansoni, underlining the major role played by the interaction between antibodies and phagocytic cells (eosinophils and macrophages).  相似文献   

8.

Background

One of the most common causes of morbidity and mortality in children with sickle cell disease (SCD) is infection with the pneumococcal bacterium (Streptococcus pneumoniae). Unfortunately, the polysaccharide-conjugate vaccine appears to be less effective in individuals with SCD when compared to the general population. We sought to better understand the relative efficacy of pneumococcal vaccination in a SCD mouse challenge model.

Methods

Transgenic control and SCD mice were monitored for mortality after intranasal pneumococcal infection or pneumococcal vaccination with Prevnar-13 and type-matched challenge. Anti-pneumococcal antibody titers were measured by ELISA and opsonophagocytosis was measured in vitro.

Results

Mortality after pneumococcal infection was similar between control and SCD mice. However, after three intramuscular polysaccharide-conjugate vaccinations, all control mice were protected following high-dose intranasal infection, whereas 60% of SCD mice died. Anti-pneumococcal antibody titers showed initial IgG and IgM responses in both groups, but waning titers were observed in the SCD group, even after boosting. When functionally assayed in vitro, serum from SCD mice 13 weeks after a second booster shot maintained little to no ability to opsonize pneumococci, while serum from control mice sustained a significantly higher capacity opsonization. Thus, it appears that SCD mice do not maintain antibody responses to pneumococcal polysaccharides after Prevnar-13 vaccination, thereby leaving them susceptible to mortality after type-matched infection.

Conclusion

Our results emphasize the need to better understand the correlates of immune protection in SCD so that pneumococcal vaccines can be improved and mortality reduced in this susceptible population.  相似文献   

9.
CBA mice which had recovered from infection with Trypanosoma musculi were immune to challenge with all strains of the homologous species that were tested but were still full susceptible to challenge with T. cruzi, T. brucei or T. evansi. A heavy challenge inoculum of T. musculi was cleared rapidly from the blood of mice which had recently recovered from infection but, in mice which had recovered 11 months earlier, the parasitaemia changed very little for 3–4 days but then fell abruptly within a few hours. Immunization with a parasite extract in multiple emulsion conferred a strong though not complete protection against homologous challenge.Serum from mice which had recovered from infection had a marked neutralizing effect in vitro on the infectivity of the homologous parasites although the numbers of live organisms were not reduced during the period of in vitro incubation. The test did not reveal antigenic differences among three isolates of the parasite.A summary is given of the sequence of events that is thought to make up the immune response of mice to T. musculi.  相似文献   

10.
Taenia taeniaeformis oncospheres, injected parenterally with or without adjuvants, stimulated a high degree of protective immunity in mice against challenge infection with eggs. Furthermore, the supernatant from a centrifuged (twice for 30 min at 4500 g) preparation of oncospheres which had been frozen, thawed and sonicated, induced more than 90% protection when used as a vaccine with adjuvant. By contrast, centrifuged (1 h at 3500 g) supernatant medium collected during 72 h incubation of activated T. taeniaeformis oncospheres in vitro in serum-free culture medium was only marginally host-protective. The results indicate that materials from disrupted oncospheres should be a suitable starting preparation for identification and purification of ‘host-protective’ antigens.  相似文献   

11.
Offspring of control female rats received colostrum from females immune to Trypanosoma gambiense after birth. Subsequently, these offspring had high titers of agglutinating and phagocytosis-promoting activities in their sera. They were not protected against challenge infection, although a delay of parasitemia and extended survival were often observed. On the other hand, the offspring of immune females, which had received colostrum from control females after birth, showed low agglutinating and phagocytosis-promoting activities in their sera; 50% were protected against infection. It was concluded that antibodies (IgG) passing through the placenta of immunized females were more effective than antibodies (IgA) derived from colostrum from immunized females in protecting offspring against trypanosome infection. Phagocytosis-promoting activity was detected in both colostral IgA-rich fractions from the colostra of immunized females and serum IgA-rich fractions from the control females' offspring, which had received colostrum from immune females. Pepsin digestion resulted in the loss of such activity. It is possible that the phagocytosis-promoting activity of IgA antibodies was not present in the products obtained by means of pepsin treatment.  相似文献   

12.
Activated oncospheres of T. hydatigena within filtration membrane diffusion chambers implanted intraperitoneally into dogs developed into larvae 3 mm in dia possessing a scolex anlage without hooks. Exogenous antigens released by developing T. hydatigena larvae failed to stimulate any measurable resistance in the dogs to challenge infection with E. granulosus protoscolices.  相似文献   

13.
Free infectious Plasmodium berghei parasites (FP) were used in a system suitable for measurement of protective antibody in the serum of rats recovered from malaria. By the fluorescent antibody technique it was demonstrated that the free parasites, but not parasites in erythrocytes, became coated with antibody after incubation in recovered rat serum. Because immune sera capable of coating free parasites did not protect mice against FP inocula, but partially or completely protected rats, it is probable that antibody coating alone is not sufficient to kill the parasites. It was further demonstrated in vitro, with one strain of P. berghei, that phagocytes more readily ingested parasites in the presence of immune serum than in the presence of normal serum. This observation suggests that phagocytosis of the antibody coated parasite probably was required to prevent infection.  相似文献   

14.
Nippostrongylus brasiliensis: effects of immunity on the pre-intestinal and intestinal larval stages of the parasite. International journal for Parasitology4: 183–191. Migration of the pre-intestinal larval stages of N. brasiliensis was studied in rats undergoing either primary or challenge infections. In rats undergoing a primary infection, more than 67 percent of larvae successfully migrated from the skin to the oesophagus by 70 h after infection, and subsequently over 90 per cent of these larvae became established in the small intestine as sexually mature adults. In immune rats undergoing a second infection, 46 per cent of larvae completed migration to the oesophagus by 70 h and of these, only 1·6 per cent became established in the intestine to produce eggs. These inhibitory effects on the pre-intestinal and intestinal larval stages were even more pronounced in immune rats undergoing a third or fourth infection and in addition, there was a prolonged sojourn and substantial retention of larvae in their lungs. There was no evidence that the immune response had an adverse effect on oesophageal fourth stags larvae as these organisms (obtained from immune donors) were able to establish and develop to maturity when transferred per os to normal animals.Syngeneic transfer of immune mesenteric lymph node cells to normal recipients, caused expulsion of parasites from the intestine but failed to effect migration of pre-intestinal larval stages. The implications of these findings are discussed in the context of current knowledge of the mechanisms of immunity to helminths.  相似文献   

15.
Alizadeh H. and Wakelin D. 1982. Comparison of rapid expulsion of Trichinella spiralis in mice and rats. International Journal for Parasitology12: 65–73. Primary infections of Tricliinella spiralis in both NIH mice and Wistar rats resulted in increased levels of mucosal mast cells and goblet cells. In mice the numbers of both cell types rose sharply before worm expulsion (days 8–10), remained at an increased level for a short time and declined quickly, reaching control levels on day 14 for goblet cells and between days 28 and 35 for mast cells. In contrast, in rats, the numbers of goblet cells and mast cells increased during worm expulsion and remained above control levels for a prolonged period. Challenge infections given shortly after expulsion of a primary infection (day 14) were expelled rapidly, worm loss being virtually complete with 24 h. In mice this response to challenge was short-lived and persisted only until day 16 after primary infection. After this time, challenge worms were expelled more slowly after infection. In rats the rapid expulsion response was expressed for at least 7 weeks after primary infection. Mice and rats showed differences in the conditions of infection necessary to prime for rapid expulsion, mice requiring larger and longer duration primary infections, but the expression of the response appeared to be similar in both species. In mice it was shown that rapid expulsion of T. spiralis was a response evoked specifically by prior infection with this species; infections with other intestinal nematodes had no effect. Similarly, the effect upon challenge infection was also specific to T. spiralis. The rapidity with which challenge infections are expelled suggests that either the specific inflammatory changes generated during primary infection result in an environment that is unsuitable for establishment of subsequent infections or that challenge infections provide a stimulus that can provoke an almost instantaneous response in the primed intestine. The relationship of the observed cellular changes to such mechanisms is discussed.  相似文献   

16.
Serum opsonins and the passive transfer of protection in Babesia rodhaini infections of rats. International Journal for Parasitology4: 197–201. An investigation into the protective activity of serum from rats immune to B. rodhaini and the role played by opsonins in that activity was undertaken. One, three and six infections with B. rodhaini resulted in corresponding increases in the titre of specific protective antibody demonstrable by the administration of immune serum to rats. Drug control of infection resulted in a lower level of protective activity than that which developed when rats controlled infection unaided. Protective activity following recovery from a single drug controlled infection was undiminished 20 weeks after infection.Serum opsonins were detected in an in vitro culture system of normal rat peritoneal macrophages and these antibodies were specific for parasitized erythrocytes. It is suggested that opsonins were largely responsible for the protective effect demonstrated by assay in rats but that their importance, relative to other antibodies with a possible protective function, in the development of acquired immunity remains to be determined.  相似文献   

17.
18.
Immunity to the coccidial parasite, Eimeria nieschulzi, in CD-F rats was assessed by the numbers of oocysts shed in relation to the time after inoculation. Intravenous injections of syngeneic thoracic duct lymphocytes (TDL) from immunized rats elicited various degrees of adoptive immunity against primary infections of E. nieschulzi. Of the 16 rats injected with 109 sensitized TDL, 7 were totally immune to a subsequent challenge by the parasite. This number of injected TDL also raised the serum antibody level to that of immune rats. Contact with immune TDL was deleterious to sporozoites of E. nieschulzi in vitro and produced immunocytoadherence of parasite to cell.  相似文献   

19.
Oral infection with mouse-derived cysticercoids (cysts) of Hymenolepis nana on day 0 did not make the 5 ± 1 week old mouse host immune to egg challenge by day 7 of the prepatent period, although the number of cyst-derived tapeworms was 1000 times greater than that of egg-derived tapeworms sufficient to make the host immune by day 7. Neither cysts recovered from immunologically competent 5 ± 1 week old donor mice, which should have become immune within 2 days of egg inoculation, nor those from incompetent 5–7 day-old baby mice given eggs when 0–2 days old made the host immune. The time course of differentiation of cysts in baby mice was not different from that in 5 ± 1 week-old mice. Mice infected twice with cysts on days 0 and 4 did not become immune either. Rapid protective immunity against egg challenge was acquired by inoculation exclusively with eggs but not with cysts. Apparently cysts differ from oncospheres in their immunogenicity. The importance of cysts for analysing the mouse—H. nana system from the immunological point of view is discussed.  相似文献   

20.
On Day 5 after immunization with Trypanosoma gambiense, spleens were removed from immune mice. Spleen cell suspensions were passed through a glass bead column and separated into filtrate and adherent cell subpopulations. Each subpopulation was transferred into normal mice intraperitoneally, and the production of agglutinins and the protection against experimental infection with T. gambiense were studied in vivo. The adherent subpopulation contained cells which were capable of producing and releasing the agglutinin into the serum of the recipient, but the filtrate did not contain such cells.The adherent fraction was found to be effective in the prevention of experimental infection, but the filtrate was only slightly effective. When both cell subpopulations were mixed together, immune responses were enhanced. With cortisone and anti-mouse thymic cell serum treatment before immunization with trypanosomal antigen, agglutinin production was greatly suppressed, and the mice were not protected against experimental infection. However, after treatment of immune spleen cells in vitro with anti-mouse thymic cell serum, recipients of viable cells showed agglutinin production and were found to withstand infection.  相似文献   

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