Factors affecting the acquisition of resistance against Schistosoma mansoni in the mouse. I. Demonstration of resistance to reinfection using a model system that involves perfusion of mice within three weeks of challenge

1978 ◽  
Vol 52 (3) ◽  
pp. 173-186 ◽  
Author(s):  
M. Doenhoff ◽  
Q. Bickle ◽  
E. Long ◽  
J. Bain ◽  
A. McGregor
Keyword(s):  
Schistosoma Mansoni ◽  
Primary Infection ◽  
Model System ◽  
Challenge Infection ◽  
Factors Affecting ◽  
Experimental Animals ◽  
Challenge Control ◽  
Excretion Rates ◽  
Homologous Challenge

ABSTRACTThe degree of resistance acquired by Schistosoma mansoni-infected mice against homologous challenge has been determined by perfusion of the animals within three weeks of the challenge, at which time the challenge-derived organisms were morphologically distinguishable from the primary infection which induced the resistance. The method has been compared with assays based on determination of the number of organisms migrating through the lung, and with perfusions at a later time when the challenge has matured. The results obtained with the three week perfusion method, showing that resistance was acquired by eight weeks after a primary infection, were confirmed by the longer survival of, and reduced egg excretion rates and tissue egg burdens in the experimental animals relative to respective challenge control animals. However, some discrepancy in challenge-derived worm numbers was found between animals perfused three weeks after challenge and those autopsied at later times. The possible reasons for this difference are discussed. The degree of resistance that was acquired was to some extent dependent on the size of the challenge infection.

Factors affecting the acquisition of resistance against Schistosoma mansoni in the mouse. The effect of varying the route and the number of primary infections, and the correlation between the size of the primary infection and the degree of resistance that is acquired

Parasitology ◽  
1980 ◽  
Vol 81 (2) ◽  
pp. 355-371 ◽  
Author(s):  
E. Long ◽  
R. Harrison ◽  
Q. Bickle ◽  
J. Bain ◽  
G. Nelson ◽  
...  
Keyword(s):  
Schistosoma Mansoni ◽  
Primary Infection ◽  
Worm Burden ◽  
The Other ◽  
Single Infection ◽  
Factors Affecting ◽  
Relative Lack ◽  
Skin Site ◽  
Homologous Challenge ◽  
Inducing Resistance

SUMMARYMice given primary infections of Schistosoma mansoni by percutaneous or subcutaneous routes were found to acquire a higher degree of resistance against homologous challenge after 7–8 weeks than mice infected intraperitoneally. Mice infected by the intraperitoneal route tended to have smaller worm burdens than those infected with the same number of cercariae by the other two routes and this may, in part, have contributed to the relative lack of efficacy of intraperitoneal infections in inducing resistance to re-infection. The same degree of resistance was acquired after primary percutaneous infection irrespective of whether it was administered in 3 equivalent weekly doses, or the same total number of cercariae was administered as a single infection. The same degree of resistance was also observed when a percutaneous challenge was administered on the same or a different skin site to that which received the percutaneous primary infection. The degree of resistance to re-infection acquired after a percutaneous primary infection correlated well with the size of the primary worm burden and the number of eggs in the intestine and liver, but did not correlate with the number of eggs in the lungs.

Factors affecting the acquisition of resistance against Schistosoma mansoni in the mouse. IV. The inability of T-cell-deprived mice to resist re-infection, and other in vivo studies on the mechanisms of resistance

Parasitology ◽  
1979 ◽  
Vol 78 (2) ◽  
pp. 171-183 ◽  
Author(s):  
M. Doenhoff ◽  
E. Long
Keyword(s):  
Schistosoma Mansoni ◽  
Primary Infection ◽  
Acquired Resistance ◽  
Challenge Infection ◽  
In Vivo Studies ◽  
Hydrocortisone Acetate ◽  
Mechanisms Of Resistance ◽  
Factors Affecting ◽  
Partial Depletion

SUMMARYCBA mice deprived of their T-cells by means of thymectomy and administration of rabbit anti-mouse thymocyte serum before a primary infection of Schistosoma mansoni, failed to resist re-infection to the same extent as immunologically intact controls. However, little difference was made to the degree of resistance to re-infection acquired by thymectomized S. mansoni-infected mice when the anti-thymocyte serum was administered after the primary infection and just before the challenge. Hydrocortisone acetate, when administered to primarily infected mice just before reinfection appeared to reduce the degree of acquired resistance, but the drug also had a schistosomicidal effect on the challenge-derived organisms. An attempt to specifically suppress the acquisition of resistance against S. mansoni by administering serum from homologously infected, resistant donors before and during the course of a primary infection failed, and partial depletion of complement activity with cobra venom factor that was administered just before challenge also failed to affect resistance. Serum obtained from mice with chronic S. mansoni infections and injected intradermally at the site of subsequent administration of a homologous percutaneous challenge infection failed to markedly inhibit maturation of the challenge in the recipient. Recipients of 3 ml of serum from heavily infected donors were also not significantly more resistant to challenge than untreated controls. However, isolated skin from heavily infected mice allowed fewer cercariae to penetrate and emerge transformed as schistosomula than did isolated skin from uninfected controls.

Factors affecting the acquisition of resistance against Schistosoma mansoni in the mouse. 2. The time at which resistance to reinfection develops

1978 ◽  
Vol 52 (3) ◽  
pp. 187-191 ◽  
Author(s):  
E. Long ◽  
M. Doenhoff ◽  
J. Bain
Keyword(s):  
Schistosoma Mansoni ◽  
Partial Resistance ◽  
Primary Infection ◽  
Factors Affecting ◽  
Degree Of Protection ◽  
Maximum Resistance ◽  
Homologous Challenge

ABSTRACTMice developed a partial resistance against homologous challenge with Schistosoma mansoni as early as two weeks after primary infections of 35 to 75 cercariae, and the degree of protection increased to an apparent maximum by 6 weeks. Animals given a primary infection of only 25 cercariae required a longer period to acquire maximum resistance.

scholarly journals The nylon bag technique in the determination of ruminal feed protein degradation

1983 ◽  
Vol 55 (1) ◽  
pp. 1-78 ◽  
Author(s):  
Jouko Setälä
Keyword(s):  
Particulate Matter ◽  
Pore Size ◽  
Control Sample ◽  
Sample Treatment ◽  
Sample Weight ◽  
Factors Affecting ◽  
Experimental Animals ◽  
Incubation Periods ◽  
Feed Protein

The investigation included experiments in which factors affecting the reliability of the nylon bag method were studied. The possibility of applying the feed protein degradabilities to practical feeding conditions was also examined. In the experiments concerning reliability, such factors as bag porosity, sample weight, sample treatment, washing procedure, diets, and differences between animals and incubation days were studied. The feed protein degradabilities were also determined by using as incubation periods the ruminal retention times for particulate matter of different feeds, evaluated as a function of DM intake/100 kg liveweight in different diets. A nylon bag, with a pore size of 40 µm and internal dimensions of 6 X 12 cm was selected for the degradability determinations. The sample weight used in incubations was 57 —60  mg DM/cm2. In the determination of feed protein degradability, when sheep are used as experimental animals, it is recommended that for routine determinations only one animal be used, analyzing the contents of two bags for each incubation period during two successive days. A control sample of which degradability is determined in advance in many sheep, should be used in all incubations in order to control the digestive processes in the rumen of the experimental sheep. The actual degradabilities analyzed by the bag method are applicable in practise, if they are determined using animals at similar feeding levels and on diets similar to those prevailing under the conditions in which the degradabilities are going to be used.

Homologous and heterologous resistance in Echinostoma revolutum infections in mice

Parasitology ◽  
1980 ◽  
Vol 80 (3) ◽  
pp. 479-486 ◽  
Author(s):  
S. B. Sirag ◽  
N. Ø. Christensen ◽  
F. Frandsen ◽  
J. Monrad ◽  
P. Nansen
Keyword(s):  
Primary Infection ◽  
Worm Burden ◽  
Challenge Infection ◽  
Control Group ◽  
Echinostoma Revolutum ◽  
Heterologous Challenge ◽  
Challenge Control ◽  
Complete Resistance ◽  
Group A ◽  
High Level

SummaryHomologous and heterologous resistance in Echinostoma revolutum infections was studied in mice. A high level of homologous resistance was demonstrated in mice harbouring a 13-day-old primary E. revolutum infection with 9–10 and 11–15 worms, corresponding to a 70·0 and 66·7% reduction in the size of the established worm burden as compared with that of the challenge control group. A 14- and 20-day-old primary infection with 3–4 worms induced a level of resistance of 61·7 and 81·8% respectively, while higher worm levels of 9–10 and 11–15 induced almost complete resistance corresponding to a 95·1–100% reduction in the size of the established worm burden. Complete resistance was also demonstrated in mice challenged 8 days after elimination of a 20-day-old primary infection with 11–15 worms by anthelmintic treatment. A primary 43-day-old Schistosoma mansoni infection induced a 73·1% reduction in the size of the established E. revolutum challenge infection while infections of an age of 79 and 99 days conferred complete resistance to heterologous challenge with E. revolutum. Primary pre-patent S. mansoni infections and a patent S. bovis infection of an age of 56 days did not induce any resistance to challenge with E. revolutum. A primary 14- and 21-day-old infection of E. revolutum did not stimulate any significant level of resistance to heterologous challenge with S. mansoni.

Cross-immunity to Schistosoma mansoni and S. haematobium in the hamster

Parasitology ◽  
1976 ◽  
Vol 73 (1) ◽  
pp. 53-64 ◽  
Author(s):  
M. A. Smith ◽  
J. A. Clegg ◽  
G. Webbe
Keyword(s):  
Schistosoma Mansoni ◽  
Primary Infection ◽  
Rabbit Antiserum ◽  
The Other ◽  
Stage Of Development ◽  
Recovery Assay ◽  
Cross Immunity ◽  
Common Antigens ◽  
High Level ◽  
Homologous Challenge

SummaryHamsters (WO strain) with a primary infection of Schistosoma mansoni or S. haematobium rapidly developed immunity to homologous challenge judged by the lung recovery assay. Immunity was detected at 4–5 weeks and reached a plateau 6 weeks after infection.Using this information, hamsters with an 8-week primary infection with S. mansoni or S. haematobium were tested for resistance to homologous reinfection and resistance to a challenge with the other species of schistosome. Primary infection with S. mansoni or S. haematobium conferred a high level of immunity to reinfection with either species of schistosome judged by the perfusion assay, involving recovery of adult worms 6–10 weeks following challenge. Estimation of the level of immunity with the lung recovery assay, 5 days after challenge, indicated that immunity due to a primary infection with S.mansoni acted at or before migration of the challenge through the lungs but immunity stimulated by a primary S. haematobium infection was only partially effective at the lung stage and substantial destruction of challenging organisms occurred at a later stage of development.Antibodies in immune sera of hamsters with a primary S. mansoni or S. haematobium infection were shown to bind to common antigens on the surface of young schistosomula of either species by u.v. microscopy using as detecting agent a fluorescein-labelled rabbit antiserum directed against hamster globulins.

Attempts to protect goats against challenge withTrypanosoma vivaxby initiation of primary infections with large numbers of metacyclic trypanosomes

Parasitology ◽  
1988 ◽  
Vol 97 (3) ◽  
pp. 383-392 ◽  
Author(s):  
G. J. Vos ◽  
S. K. Moloo ◽  
R. T. Nelson ◽  
P. R. Gardiner
Keyword(s):  
Primary Infection ◽  
Antibody Responses ◽  
Trypanosoma Vivax ◽  
Diminazene Aceturate ◽  
Experimental Animals ◽  
Large Numbers ◽  
Variable Antigen ◽  
Homologous Challenge ◽  
Different Doses ◽  
Group 1

SummaryAttempts were made to immunize goats by infection with large numbers of metacyclic trypanosomes of a clone ofTrypanosoma vivax, followed by chemotherapy. Five groups of 6 goats each were infected intradermally with 5 different doses of cultured metacyclics ofT. vivax, ranging from 102to 106trypanosomes/goat. Four weeks after infection, the goats were treated with 10 mg/kg diminazene aceturate (Berenil, Hoechst A.G.). Three weeks after treatment, 3 goats in each group were challenged intradermally with 104homologous metacyclics derived from culture. The remaining 3 goats in each group were challenged by 20 tsetse infected with the homologous clone. Five out of 30 goats were resistant to homologous challenge; 4 of the goats that had been challenged with cultured parasites, and 1 that had been challenged by tsetse. In each group 1 goat was protected. Protection was therefore not apparently influenced by the number of trypanosomes used to establish the primary infection. In another experiment, 6 goats were each infected by feeding 100 tsetse on the goats for 15 consecutive days. Three weeks after infection the goats were treated with Berenil and 3 weeks later challenged by 20 tsetse infected with the homologous clone. Three out of the 6 goats resisted challenge. The susceptible goats in both experiments, however, showed a reduction in the peak of parasitaemia following challenge compared with both challenge controls and the initial infections. Lytic antibodies to cultured metacyclics ofT. vivaxwere detected in goats that resisted challenge after a primary infection with cultured metacyclics, and in resistant and susceptible goats after a primary infection by tsetse. All infected goats produced lytic antibodies to live bloodstream forms, as well as antibodies to bloodstream form lysates (demonstrated by ELISA). It is suggested that the immunity that had been induced in some of the experimental animals is due to antibody responses to both metacyclic and bloodstream variable antigen types (VATs) expressed during infection.

Induction of immunological tolerance in rats to Nippostrongylus brasiliensis infection

Parasitology ◽  
1967 ◽  
Vol 57 (3) ◽  
pp. 403-418 ◽  
Author(s):  
T. Kassai ◽  
I. D. Aitken
Keyword(s):  
Primary Infection ◽  
Worm Burden ◽  
Immunological Tolerance ◽  
Challenge Infection ◽  
The Other ◽  
Nippostrongylus Brasiliensis ◽  
Laboratory Rats ◽  
Successful Attempt ◽  
Other Hand

A successful attempt was made to induce immunological tolerance to N. brasiliensis in laboratory rats by exposing them to larval infections before the age of immunological maturity.The adult capacity of rats to eliminate a primary infection in 3 weeks and to acquire resistance to reinfection was developed by 5 weeks of age. On the other hand, primary infections of 250–660 larvae, originating before 4 weeks of age, survived in 61 of 83 rats up to 10 weeks. These rats were not resistant to challenge at 5 or 7 weeks of age, nor did the challenge infection undergo immune elimination. Such tolerance was evident even in rats whose primary worm burden was chemically abbreviated prior to challenge.It was not always possible to distinguish between tolerant and immune animals on the basis of egg output patterns. Suppression of egg output occurred even in tolerant rats harbouring relatively stable female populations.For immunological experiments on N. brasiliensis infection in rats, the determination of a ‘take ratio’ is advocated: (20 day take/10 day take) × 100. This ratio eliminates the error inherent in variability of takes and renders comparable the results of different experiments.The work was carried out in 1965 during tenure by one of us (T.K.) of an Exchange Scholarship under the British–Hungarian Cultural Agreement. Supervision by Professor W. Mulligan and the co-operation of colleagues in the Wellcome Laboratories are gratefully acknowledged.

Induction of protective immunity toBrugia pahangiin jirds by drug-abbreviated infection

1992 ◽  
Vol 66 (2) ◽  
pp. 147-154 ◽  
Author(s):  
Y. Horii ◽  
H. Nakanishi ◽  
A. Mori ◽  
M. Ueda ◽  
K. Kurokawa ◽  
...  
Keyword(s):  
Post Infection ◽  
Primary Infection ◽  
Protective Immunity ◽  
Challenge Infection ◽  
Significant Protection ◽  
Patent Period ◽  
Infection Period ◽  
Degree Of Protection ◽  
Infected Adult ◽  
Homologous Challenge

ABSTRACTProtective immunity of homologous challenge infection was examined in jirds after drug-abbreviated infection withBrugia pahangi. Mebendazole (MBZ) treatment at the early prepatent (5–7 weeks of post infection) or the late prepatent (7–9 weeks of post infection) period was highly effective in causing almost complete eradication of the primary infection. After challenge infection, the worm burden was significantly reduced 19% (31·1 in average) and 77% (9·5) to that of the controls (38·8 and 41·7), respectively. The magnitude of eosinophil response paralleled the degree of protection. No or only a few microfilariae were seen after challenge infection in jirds treated during the prepatent periods. They were also resistant to intravenous challenge with the microfilariae ofB. pahangi. MBZ treatment at the patent period was, on the contrary, incomplete against primarily infected adult worms, and was not able to induce either significant protection (30·1 vs 33·1 in control) or eosinophil response to the challenge infection.

Interactions of the cysticercoids of Hymenolepis diminuta and Raillietina cesticillus in their intermediate host, Tribolium confusum

Parasitology ◽  
1985 ◽  
Vol 90 (3) ◽  
pp. 421-431 ◽  
Author(s):  
D. M. Gordon ◽  
P. J. Whitfield
Keyword(s):  
Intermediate Host ◽  
Primary Infection ◽  
Challenge Infection ◽  
Tribolium Confusum ◽  
Hymenolepis Diminuta ◽  
Ecological Significance ◽  
Experimental Exposure ◽  
Establishment Success ◽  
Homologous Challenge

This study was based on the experimental exposure of beetles to homologous and heterologous infections of Hymenolepis diminuta and Raillietina cesticillus. The results demonstrated that, for both species over the range of parasite densities employed, the presence of a primary infection had no effect on the establishment success of an homologous challenge infection. The establishment success of R. cesticillus cysticercoids was not affected by the presence of an H. diminuta infection. The existence of an R. cesticillus infection, however, severely reduced the establishment success of an H. diminuta infection. The reduction in H. diminuta establishment was greatest in R. cesticillus infections less than 10 days old. The plausibility of some of the mechanisms that are potentially responsible for the reduction in H. diminuta establishment success is discussed, as is the possible ecological significance of these results.

Sign in / Sign up

Export Citation Format

Share Document