bluuebunny/crossref_metadata_2025 huggingface dataset:
Antibody responses in mice protected against malaria by vaccination
Authors: PLAYFAIR J.H.L. , SOUZA J.B.DE
Published: October 2007

Summary Mice were vaccinated against lethal P. yoelii or P. berghei malaria and their immunofluorescent anti‐parasite antibody levels followed after infection with live homologous parasites. There was a good correlation between antibody titres (especially IgG) and protection, under various experimental conditions, including: different doses of vaccine, different strains of mice, and increase or decrease of macrophage function. When antiserum was passively transferred to normal recipients, protection against challenge also correlated with antibody titre, though even with high titres only a small number of parasites could be completely eliminated. P. berghei was much more difficult to protect against than P. yoelii, despite similar antibody responses. We conclude that antibody is important in the protective effect of vaccination, but that other properties of both the host and the parasite influence its effectiveness.
Increased hepatotoxicity of bacterial lipopolysaccharide in mice infected with Schistosoma mansoni
Authors: FERLUGA J. , DOENHOFF M.J. , ALLISON A.C.
Published: October 2007

Summary Mice infected with Schistosoma mansoni were highly sensitive to the lethal effects of bacterial lipopolysaccharide (LPS).The hyper‐reactive state of LPS coincided with the development around the parasite eggs of multiple granulomas in the liver. Elevated aspartate transaminase levels in blood and severe hypoglycaemia in LPS‐challenged animals indicated extensive liver parenchymal cell damage. There was also a complete depletion of glycogen in hepatocytes of these animals. From this work and studies on other hepatitis models, it is suggested that individuals affected with granulomatous disorders may be at risk because of everyday exposure to LPS from the gut.
Murine Schistosomiasis mansoni: anti‐schistosomula antibodies and the IgG subclasses involved in the complement‐ and eosinophilmediated killing of schistosomula in vitro
Authors: RAMALHO‐PINTO F.J. , ROSSI ROSEMARY DE , SMITHERS S.R
Published: October 2007

Summary Protein A‐sepharose affinity chromatography was used to isolate IgG subclasses from the serum of CBA mice chronically infected with Schistosoma mansoni. The subclasses were tested for the presence of two antibodies which are responsible for the death of young schistosomula in vitro; ‘lethal antibody’ (LA), which kills schistosomula in co‐operation with complement and ‘eosinophil adherence antibody’ (EAA) which causes the death of schistosomula by promoting the adherence of eosinophils to the parasite. LA and EAA were detected only in the IgG fraction of the serum. LA was concentrated in the IgG2a fraction and EAA in the IgG1 fraction. The development of IgG subclasses specific for schistosomula was followed in mice exposed to twenty cercariae by the fluorescent antibody technique. IgG1, IgG2a and IgG2b antibodies were detected 2 weeks after infection and their titres rose steadily to reach high levels by weeks 12 or 14. IgM antibody was not detected until week 6 and IgA until week 10; both were present at lower concentrations than the IgG1 antibodies.
Histopathological changes following primary, secondary and repeated infections of rats with Strongyloides ratti, with special reference to tissue eosinophils
Authors: MOQBEL R.
Published: October 2007

Summary The histopathological responses to the nematode Strongyloides ratti have been studied in rats following single and multiple percutaneous infections. Under these conditions, rats developed an effective immune response which was shown to be retrophasic, i.e. during primary infection, adult worms in the small intestine were the main target of the response: during secondary infection, the intestinal and, more strongly, the pulmonary phases were affected; following multiple infections, the response was principally effective during the cutaneous phase. An increase in the number of tissue eosinophils in all these sites was a common feature which varied according to the level of immunity acquired by the host. There was an increase in the percentage of degranulated mesenteric mast cells which coincided with the expulsion of the intestinal phase during primary and secondary infections. No direct contact between eosinophils and any stage of the parasite was seen in the small intestine or lungs of normal and immune rats during primary and secondary infections. However, in the skin of hyperimmune rats, eosinophils increased rapidly (within 3–6 h) forming eosinophil‐rich granulo‐mata in which eosinophils were seen in close contact with the cuticle of the invading larvae. This may suggest an in vivo effector role for these cells. This and other possible roles of eosinophils in vivo have been discussed in the light of the in vitro action of eosinophils in other parasitic systems. Both the tissue eosinophil response and the percentage of degranulation of mesenteric mast cells, during the intestinal phase, were affected following treatment with corticosteroids.
A study of the antigens produced by adult Fasciola hepatica maintained in vitro
Authors: LEHNER R.P. , SEWELL M.M.H.
Published: October 2007

Summary Metabolic antigen of adult Fasciola hepatica was prepared by concentrating the culture medium in which 100 adult flukes had been maintained in vitro for 7 days. Serological reactions between this antigen and sera from fluke‐infected rabbits, rats and sheep were studied using immunodiffusion in agar and enzyme linked immunosorbent assay. The used medium contained a number of antigenic components and their various reactions with the sera from these different hosts were investigated.
Studies on the responsiveness of spleen cells to various polyclonal T and B cell activators during Trichinella spiralis infection
Authors: LJUNGSTRÖM I.
Published: October 2007

Summary Spleen cells from mice infected with Trichinella spiralis 1, 2, 3 and 8 weeks before the assay, were stimulated with various polyclonal T and B cell activators. It was observed that T. spiralis infection was accompanied by increased spontaneous DNA synthesis which probably reflects lymphocyte activation in vivo. The infection also caused a depressed T cell reactivity during the intestinal stage (1 week after infection) and enhanced DxS response during the late muscular stage (8 weeks after infection). The depression of T cell reactivity seems to reflect qualitative rather than quantitive changes, presumably associated with the regulation of the host's specific immune response to the parasitic antigen. The increased response to DxS may partially be associated with increased macrophage activity. Attempts to evaluate the effects of infection on the reactivity of the cells to PHA and Con A during the migration stage and onwards, to PPD and LPS during the whole observation period and to DxS before the late muscular stage gave conflicting results.
Studies on the mechanisms of adverse reactions produced by diethylcarbamazine in patients with onchocerciasis—Mazzotti reaction
Authors: GUERRA‐CACERES J.G. , BRYCESON A.D.M. , QUAKYI I. , SPRY C.J.F.
Published: October 2007

Summary The treatment of patients with onchocerciasis with diethylcarbamazine (DEC) can produce local or systemic reactions within a few hours—the Mazzotti reaction. In order to study the immunological mechanisms which could underly this reaction, three patients were studied who were undergoing treatment, and two normal subjects who had been treated successfully previously were controls. Blood eosinophils were vacuolated and a higher proportion than normal had Fc receptors. After taking 50 mg DEC orally, in parallel with the development of symptoms in the three patients, localised in two and generalized in one, there was a fall in blood eosinophil counts which were lowest at 12 h. Serum IgG levels fell slightly in all three patients, and the serum IgE level fell in one, but there were no changes in the titres of antimicrofilarial antibodies. Levels of circulating immune complexes were not elevated at any time, and complement levels did not alter during the reaction. From these findings and a review of previous work on the mechanisms of the Mazzotti reaction it is suggested that when microfilarae are damaged by DEC, an inflammatory reaction is produced which may be localised or generalized. The reaction does not appear to require the generation of circulating immune complexes, or systemic complement activation, even when the reaction is generalized. It is suggested that the clinical features of the reaction may be due to the effects of mediators secreted from inflammatory cells including eosinophils, in sites where microfilarae are being destroyed.
Coccidiosis: localization of lymphoblasts in the infected small intestine
Authors: ROSE M. ELAINE , HESKETH PATRICIA , OGILVIE BRIDGET M.
Published: October 2007

Summary Peripheral blood lymphocytes of chickens and thoracic duct lymphocytes and mesenteric lymph node cells of rats, were labelled with 125‐deoxyuridine and injected intravenously into chickens or rats respectively. Sixteen to 18 h later the intestines of coccidia infected animals contained more radioactivity than those of uninfected controls. This result was obtained with cell suspensions from both infected and normal donors indicating that, as with nematode infected rodents, the increased homing of the cells to parasitised gut was not antigen specific. In chickens the stimulus which causes the increased homing of cells to the intestine was induced within hours of parasite inoculation. This reflects the rapid response of this host, previously described with other parameters, and which may be characteristic of birds.
Genetic control of immunity to parasites: adoptive transfer of immunity between inbred strains of mice characterized by rapid and slow immune expulsion of Trichinella spiralis
Authors: WAKELIN D. , DONACHIE ANNE M.
Published: October 2007

Summary Adoptive transfer of immunity with immune mesenteric lymph node cells (IMLNC) was used to analyse the roles of immune and inflammatory events in determining the strain‐characteristic time of expulsion of Trichinella spiralis from mice. Transfer of IMLNC within and between three rapidly responding strains (NIH, SWR, DBA1–all H‐2q) resulted in accelerated worm expulsion, worm loss commencing before day 8 in each case. When NIH cells were transferred to slow‐responder B10 congenic mice (B10G‐H‐2q) mice, immunity was evident at 8 days as a reduction in worm fecundity and only by 12 days as a reduction in worm numbers. A similar result was obtained when B10G cells were given to B10G recipients. In the reciprocal transfer, IMLNC from B10G transferred immunity to NIH as effectively and as rapidly as did NIH cells. Cells capable of transferring immunity were present in B10G mice as early as 4 days after infection, even though worm expulsion in this strain does not occur until after day 12. Thus following heterologous transfers of IMLNC, the time of worm expulsion was determined by the response of the recipient, and presumably by the ability to generate intestinal inflammatory changes. Earlier work has shown that the strain‐characteristic time of worm expulsion is genetically determined, but not by H‐2 linked genes. A corollary of the present work is that non‐H‐2 linked genes control the generation of intestinal inflammatory changes in T. spiralis infections. H‐2 genes may control lymphocyte responsiveness to infection and the haplotype H‐2q may determine a rapid response. Comparisons are made with the genetic control of resistance to Listeria monocytogenes and possible mechanisms are discussed.
Immunological regulation of experimental cutaneous leishmaniasis. 2. Studies with Biozzi high and low responder lines of mice
Authors: HALE CHRISTINE , HOWARD J.G.
Published: October 2007

Susceptibility to Leishmania tropica was studied in Biozzi‘high’(Ab/H) and‘low’(Ab/L) responder mice of Selections I and III which, although originally selected with heterologous erythrocytes and Salmonella flagellar antigens respectively, both show non‐specific separation of antibody responses. Ab/H Sel I rapidly develop large, ulcerated, progressive, non‐healing lesions (occasionally desseminating fatally) accompanied by rising serum antibody titres. Ab/L Sel I produce only small lesions, even with the largest infecting dose, which heal after 2 months with minimal antibody responses. Specific delayed‐type hypersensitivity (DTH) levels found in both are normal and equivalent. (Ab/H × Ab/L)F1 mice behave intermediately. A smaller inter‐line difference is only detectable in Sel III with lower infecting doses. Both Ab/L and Ab/H mice given high doses develop chronic non‐healing disease. These results imply that spontaneous resolution of cutaneous L. tropica lesions during the immune phase is independent of humoral antibody. While the great resistance and slower development of lesions found in Ab/L Sel I are entirely consistent with the macrophage‘hyperactivity’characteristic of the line, attempts to demonstrate this in vitro with comparisons of infected peritoneal exudate cells have been inconclusive so far.
Bovine immune response to African trypanosomes: specific antibodies to variable surface glycoproteins of Trypanosoma brucei
Authors: MUSOKE A. J. , NANTULYA V. M. , BARBET A. F. , KIRONDE F. , McGUIRE T.C.
Published: October 2007

Cattle were infected with two different clones of Trypanosoma hrurei (MITat 1.2 and ILTat 1.3) and antibody response was followed by radioimmunoassay. In four of the seven animals there were at least two peaks of antibody activity to the infecting clones, with the second peak much higher than the first. Specific antibodies (IgG1 and IgM but not IgG2) were eluted from the immunoabsorbent columns on which the variant surface glycoproteins (VSGs) were coupled. By neutralization of infectivity tests, IgM antibodies from the first peak of antibody activity were more efficient in neutralizing trypanosomes than IgGl but the reverse was true of the antibodies isolated from the second peak. By absorption with multiple variable antigen types isolated during the course of infection, all the IgM and IgG1 in the first 3 weeks of infection were shown to be specific. It is suggested that polyclonal B cell stimulation leading to dysfunction in the control of IgM and IgG production may not be responsible for the high levels of these immunoglobulins in bovine trypanosomiasis.
Neutrophil‐mediated cytotoxicity to schistosomula of Schistosoma mansoni in vitro: studies on the kinetics of complement and/or antibody‐dependent adherence and killing
Authors: INCANI R.N. , McLAREN DIANE J.
Published: October 2007

The capacity of rat peritoneal neutrophils to adhere to and kill schistosomula of Schistosoma mansoni in vitro has been investigated. Neutrophils adhere readily to schistosomula in the presence of antibody plus complement (C) (fresh immune rat serum), antibody alone (heat‐inactivated immune rat serum) and C alone (fresh normal rat serum), but not with heat‐inactivated normal rat serum. However, schistosomular killing is only achieved with neutrophils and fIRS or MRS. In the presence of hiIRS the cells detach after 6 h without producing a significant level of parasite death. The system involving neutrophils plus fIRS is the most efficient in terms of serum dilution and the rate of schistosomular killing. The complement‐dependent antibody involved in this system belongs to the class IgG and occurs in rat serum at peak titres, 6–8 wk after a primary schistosome infection. Neutrophil adherence in the presence of MRS depends upon the generation of C3b molecules at the parasite surface via the alternative pathway of C activation. Studies on the antibody alone system indicate that the lack of significant schistosomular killing might result from the absence of factors which stimulate cell migration, since if a chemokinetic agent is introduced into the assay a 30% increase in mortality is recorded. The possible participation of neutrophils in the destruction of a primary and/or challenge infection in vivo is discussed.
An analysis of allergy, immunoglobulin E, and diagnostic skin tests in schistosomiasis
Authors: WELTMAN J. K. , SENFT A. W.
Published: October 2007

Factors governing the sensitization or desensitization of basophils and mast cells are discussed. Mathematical models are proposed which illustrate the effects of rising or falling specific or non‐specific IgE titres on the tendency of these cells to degranulate. The models presented are consistent with the hypothesis that fine‐tuning of the degranulatory event is achieved by one or more of the following mechanisms: alteration of the number of IgE receptors on the mast cell membrane; displacement of specific anti‐schistosomal IgE by anti‐other‐IgE molecules; clipping or otherwise inactivating mast cell‐fixed specific IgE receptor sites so as to render these incapable of binding antigen. Mechanisms proposed may explain how a mast cell population may evolve from highly sensitive to non‐reactive allergic states during early and/or chronic periods of schistosomiasis, only to revert to highly sensitive states once again, after the disease has been overcome.
Humoral mechanisms in the immune response of insects to larvae of Hymenolepis diminuta (Cestoda)
Authors: LACKIE ANN M.
Published: October 2007

Previous work has shown that larvae of Hymenolepis diminuta are not encapsulated by the haemocytes of the locust, Schistocerca gregaria, but are encapsulated by haemocytes of the cockroach, Periplaneta americana. The specificity of the cellular immune response in vivo, and of the agglutinating activity of the sera against vertebrate erythrocytes in vitro, is known to differ between the two species of insect. Accordingly, the sera of each of these species was tested for its agglutinating activity in vitro against a pure suspension of a known number of freshly‐hatched oncospheres of H. diminuta; it was found that serum of P. americana strongly agglutinated oncospheres while the serum of S. gregaria had no effect. The agglutinating activity of cockroach serum was only partially removed by preadsorption with either human, rat or rabbit erythrocytes, all of which are strongly agglutinated by the serum. Although the function in vivo of this agglutinating activity directed against oncospheres is not known, it is suggested that this observation—that both the haemocytes and serum of one insect species respond to the parasite whereas the serum and haemocytes of another species apparently do not—may be of some relevance to the immune recognition mechanisms of insects.
Partial purification and characterization of protection‐inducing antigens from the muscle larva of Trichinella spiralis by molecular sizing chromatography and preparative flatbed isoelectric focusing
Authors: DESPOMMIER D.D.
Published: October 2007

The soluble portion of a large particle fraction which was derived from the muscle larva of T. spiralis was subjected to molecular sizing column chromatography using Sephacryl S‐200. Five major peaks of 280 nm absorbing material were obtained. Analysis by immunoelectrophoresis revealed that each peak contained antigens, with the majority of them occurring in peaks 3,4 and 5. Preliminary studies indicated that peak 4 (mol. wt range 20 000‐10 000) contained protection‐inducing antigens. Crossed‐immunoelectrophoretic and single‐dimension electrophoretic analysis of peak 4 revealed a minimum of 10 antigens, while analytical isoelectric focusing demonstrated the presence of proteins with widely different pl, ranging from 4·0 to 9·0. Peak 4 was fractionated by preparative flatbed isoeletric focusing (PIEF) using two gradients: one from 3·5 to 9·5 and the other from 3·5 to 5·5. Fused rocket immunoelectrophoretic (FRIEP) analysis of both runs indicated that several antigens were separated from the others: one at pl 4·0 and the other at pl 9·0. The remaining antigens focused between pl 4·3 and 4·9. One hundred micrograms of whole peak 4, pl 9·0 antigen and the group of antigens at pl 4·3–4·9 were each separately injected, along with Freund's complete adjuvant, into mice. In addition, a portion of the pl 4·0 antigen was also assayed for protection. All antigenic preparations induced significant levels of protection. The pl 4·0 was further analysed on high‐performance liquid chromatography (HPLC). Two sharp peaks of antigen, as detected by FRIEP, were eluted isocratically with 65% acetonitrile from a (2–18 (aliphatic) column. Both peaks of antigen showed complete cross‐reactivity on FRIEP and absorbed at 220 nm. Amino acid analysis of each HPLC peak revealed no detectable differences in composition. Each peak contained a predominance of aspartic (13 mol%) and glutamic (18 mol%) acid. This antigen did not contain significant quantities of aromatic amino acids, and absorbed strongly at 206 nm. Neither the pl 4·0 or pl 9·0 antigen stained positively with the PAS reaction.
Non‐specific immune responses in CBA/N mice infected with Trypanosoma brucei
Authors: GASBARRE L.C. , FINERTY J.F. , LOUIS J. A.
Published: October 2007

CBA/N mice carry a genetic defect which causes a maturational arrest of normal B lymphocyte development, and results in an inability to mount IgM antibody responses against certain T lymphocyte‐independent antigens. These mice were found to survive an experimental infection with Trypanosoma brucei two to three times longer than conventional mice. This enhanced survival does not appear to be related to the level of infection of the host since parasitaemias were similar in all strains tested. In addition, the level of non‐specific polyclonal B cell activation as assessed by the enumeration of anti‐TNP antibody‐producing cells in the spleens of infected animals was found to be similar in CBA/N, CB A/CaT6 and A/J mice. In contrast, the level of circulating immune complex‐like material was lower in CBA/N mice at a time when mice of other strains were dying from the effects of the infection. Finally, although CBA/N mice survive a T. brucei infection for a longer time interval, they exhibit a non‐specific immunosuppression similar to that seen in conventional mice.
Taenia solium: mitogenic effect of larval extracts on murine B lymphocytes
Authors: SEALEY M. , RAMOS C. , WILLMS KAETHE , ORTIZ‐ORTIZ L.
Published: October 2007

The effect of an extract (CE) obtained from Cysticercus cellulosae on the proliferation of lymphocytes was studied in cultures of murine spleen cells. The addition of CE to the cultures resulted in the highly significant uptake and incorporation of tritiated thymidine (3H‐TdR) into DNA. This phenomena was dose‐dependent, with doses lower and higher than the optimal concentration causing less marked effects. The kinetic peak of this response was found to occur on day 2 of culture. CE evoked a proliferative response in cultures of spleen cells from congenitally athymic (nu/nu) BALB/c mice. Cultures of bone marrow‐derived (B) lymphocytes, generated by treatment of spleen cells with rabbit antithymocyte serum and complement, incorporated 3H‐TdR to a degree similar to that of normal spleen cell cultures. CE did not induce the proliferation of thymocytes. To eliminate the possibility that the mitogenic effect of CE was due to LPS, we carried out experiments using Polymyxin B (PB). CE was mitogenic after treatment with PB which inactivated the LPS effect. In addition, CE elicited 3H‐TdR uptake in spleen cells from the LPS nonresponsive C3H/HeJ mouse strain.
Effect of immunosuppression on the size and metastasis of amoebic liver abscesses in hamsters
Authors: GHADIRIAN E. , MEEROVITCH E.
Published: October 2007

The effect of T‐cell depletion on experimental hepatic amoebiasis in hamsters was investigated. Thymectomized and anti‐T‐cell (ATS) treated animals as well as sham‐operated and unoperated controls were inoculated intrahepatically, following laparotomy, at 7 weeks of age with 1 × 105 axenic trophozoites of Entamoeba histolytica. In neonatally thymectomized hamsters the mean weight of the liver abscess 10 days post‐inoculation was significantly greater than in neonatally sham‐operated or unoperated controls, but there was no significant difference between these groups of animals in the size of metastatic foci to other organs. On the other hand, a combination of neonatal thymectomy and ATS treatment enhanced both the size of the primary abscess in the liver and the size of metastases to other sites. Adult thymectomy did not have a significant effect either on the size of the primary abscess or on metastatic dissemination of amoebae from the liver. Treatment of hamsters with ATS shortly before or after intrahepatic challenge increased significantly the size of the abscess, but similar treatment 2–3 weeks prior to challenge had no effect. These observations suggest that thymus‐dependent cell‐mediated immunity plays an important role in the host response to E. histolytica infection.
Thymus graft reconstitution of T‐cell‐deprived mice infected with Trypanosoma musculi
Authors: TARGETT G.A.T. , LEUCHARS ELIZABETH , DAVIES A.J.S. , VIENS P.
Published: October 2007

T‐cell‐deprived CBA mice were given thymus graft implants during the course of an infection with Trypanosoma musculi and at a time when the parasitaemia was high. As a consequence of the grafts, most of the mice survived the infection whereas control ungrafted mice died. In grafted animals there was generally a period of 6&80 days after grafting during which time parasitic numbers remained high, and a further period of 200 or more days when trypanosomes were still detectable in the circulation. The mice were highly variable in their responses and possible reasons for this are considered.
The binding of antibodies from Plasmodium berghei‐infected rats to isoantigenic and parasite‐specific antigenic sites on the surfaces of infected reticulocytes
Authors: BROWN K. N. , McLAREN DIANE J. , HILLS L. A. , JARRA W.
Published: October 2007

Summary Ferritin‐labelling techniques at the ultrastructural level have shown that antiserum from August rats immune to P. berghei infection contains antibodies which bind to the surfaces of parasitized reticulocytes but not to uninfected cells. Two antibody specificities have been demonstrated by comparing antisera i absorbed with infected reticulocytes, ii absorbed with uninfected reticulocytes, and iii unabsorbed. Ferritin labelling was much increased with antiserum preabsorbed with uninfected reticulocytes, and also with heat‐inactivated serum, indicating a blocking effect on parasite‐specific antibody binding by cold‐reacting anti‐erythrocyte isoantibodies known to be present. Energy‐dependent aggregation, shedding and endocytosis of labelled material was observed at the surfaces of unfixed infected reticulocytes.
Giardiasis in mice: analysis of humoral and cellular immune responses to Giardia muris
Authors: ANDERS R. F. , ROBERTS‐THOMSON I. C. , MITCHELL G. F.
Published: October 2007

Summary Humoral and cellular immune responses have been evaluated in two inbred strains of mice which differ markedly in their susceptibility to infection with Giardia muris. Serum IgG and IgA antibody levels and IgA levels in intestinal washes were determined by a solid‐phase radioimmunoassay using G. muris antigen prepared by sonication of trophozoites, while cell‐mediated immunity was assessed by a radiometric ear‐assay for delayed‐type hypersensitivity. Following infection of BALB/c mice (resistant) and C3H/He mice (susceptible), the IgG and IgA antibody levels in serum progressively increased over the period of study with C3H/He mice having significantly higher titres of IgA antibodies than BALB/c late in the infection. Systemic immunization with G. muris trophozoites resulted in high titres of IgG antibodies in the serum. IgA antibodies were detected in intestinal washes 2 weeks after infection with a subsequent fall in levels in BALB/c mice but a progressive increase in levels in C3H/He mice. Prior immunization resulted in IgA antibodies being detected earlier in the intestinal washings after a challenge infection. Delayed‐type hypersensitivity to G. muris antigens could not be detected during an infection but a positive response was elicited following antigen priming in mice pretreated with cyclophosphamide. The immune responses evaluated in this study were assessed using a whole G. muris trophozoite sonicate and variations in the quantitative aspects of the responses did not account for observed differences in the course of infection in the two strains of mice.
Vaccination to prevent transmission of Plasmodium yoelii malaria
Authors: MENDIS K. N. , TARGETT G. A. T.
Published: October 2007

Summary It was possible to block the transmission of infection of the rodent malaria parasite Plasmodium yoelii nigeriensis to Anopheles stephensi mosquitoes 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 specific.
The unspecific antibody response to N. meningitidis group A capsular polysaccharide often seen in bacteraemic diseases
Authors: KÄYHTY HELENA
Published: October 2007

When studying acute and convalescent phase sera of patients with bacteraemic diseases, an unexpected rise of antibody activity (measured as binding of radioactive antigen) towards the capsular polysaccharide of Neisseria meningitidis group A (MenA) was observed in 59 out of 292 patients whose infection was caused by other organisms (other groups of N. meningitidis, Haemophilus influenzae, Streptococcus pneumoniae, Escherichia coli or Staphylococcus aureus). This non‐specific reaction was not seen in non‐bacteraemic diseases (Mycoplasma pneumonia, viral meningitis) or after immunization with H. influenzae type b capsular polysaccharide or Salmonella and cholera whole cell vaccines. The ‘unspecific’ anti‐MenA antibodies were of all immunoglobulin classes A, G and M tested, and had lower avidity than did those in the specific response. They were clearly inhibitable by N‐acetylmannosamine which inhibited the specific antibodies only marginally.
Trypanosoma brucei: the mechanism of remission in murine infections. A calculator simulation
Authors: HERBERT W. J.
Published: October 2007

A simulation (using an electronic calculator program) of the growth of Trypanosoma brucei in the mouse is presented. This suggests that remission of the infection is effected by the removal of ever increasing numbers of the organisms as the immune (antibody) response develops, rather than that a gradual build‐up of antibody on each trypanosome occurs until a fatal concentration is reached, simultaneously, on all of them. The program has enabled a theoretical examination to be made of the effect, on the trypanosome growth curve, of altering the doubling time of the organism, the rate of development of the immune response, and the efficiency of the antibodies. Suggestions are made for further extensions of the program to cover other parameters that may vary during the infections. It should also be possible to use similar simple programs, that do not employ advanced mathematics, to problems of the growth of many organisms.
Eosinophilia, granuloma formation and migratory behaviour of larvae in the congenitally athymic mouse infected with Toxocara canis
Authors: SUGANE K. , OSHIMA T.
Published: October 2007

Peripheral blood eosinophilia, histology of skeletal muscle and brain, and larval recovery were compared between congenitally athymic nude mice (nu/nu) and thymus‐bearing heterozygous littermates (nu/+) for 6 weeks following oral infection with Toxocara canis eggs. By comparing patterns of peripheral blood eosinophil levels in nu/+ and nu/nu, two types of eosinophilias, one T cell dependent and the other independent, were observed. Eosinophil infiltration and granuloma formation around larvae in the skeletal muscle were weaker in degree in nu/nu than nu/+. The total number of larvae in nu/+ decreased from 2 to 6 weeks after infection. This decrease was directly related to a decrease in larval number in skeletal muscle, not in brain or other tissues. In contrast, no significant decrease of the total number of larvae was observed in nu/nu. The results indicate that eosinophilia, granuloma formation and larval recovery are closely related to cell‐mediated immune mechanisms in T. canis‐infected mice.
Polyamine oxidase‐mediated killing of African trypanosomes
Authors: FERRANTE A. , ALLISON A. C. , HIRUMI H.
Published: October 2007

African trypanosomes, Trypanosoma brucei brucei, T. vivax and T. congolense, were killed when incubated in vitro with ruminant sera in the presence of exogeneous spermidine, and were non‐infective for mice. Purified polyamine oxidase in the presence of spermidine‐mediated similar killing of trypanosomes. The abundance of polyamine oxidase activity in ruminant sera which can react with polyamines to produce products with cytotoxic properties may explain the trypanosome killing. This system may contribute to non‐specific parasite killing in vivo.
Progressive sensitization of circulating basophils against Ixodes ricinus L. antigens during repeated infestations of rabbits
Authors: BROSSARD M. , MONNERON J.‐P. , PAPATHEODOROU V.
Published: October 2007

The sensitivity of rabbit basophils to antigens from Ixodes ricinus females has been studied by a degranulation test. Observations of basophil numbers and degranulation were made on the 6th day of each of four sequential infestations. Maximal degranulation of cells was observed after challenge of cells with antigen at a concentration of 106 and 107 pg/ml. At these concentrations, during a 1st infestation, 21.8 and 23.6% of cells degranulated. During a 2nd infestation, these percentages increased (34.8 and 33.8%) and reached 59.8 and 63.8% by the 4th infestation. A plasma factor which partially blocks basophil degranulation, is described. This was already present during the 1st infestation, since in its presence the percentage of degranulation was reduced by 2.8 and 4.0% respectively on challenge with 106 and 107 pg antigen/ml. Inhibition was maximal at the 4th infestation (difference: 16.5 and 20.5%). Basophil sensitization and inhibition of the degranulation are thus both progressive phenomena. After 10–15 infestations on four other rabbits, 75. 0 and 79. 8% degranulation was obtained. The inhibition of degranulation by plasma was also greater (difference: 25. 5 and 27. 4%). IgG specific anti‐I. ricinus antibodies were identified by indirect immunofluorescence. In two animals, they were detected at the 6th day of the 1st infestation. Subsequently, they were generally present for all the animals.
Chemokinetic factors obtained from the larval stage of the cestode, Taenia taeniaeformis
Authors: CAMP C. J. , LEID R. WES
Published: October 2007

Saline extracts of the metacestodes of Taenia taeniaeformis were shown to have chemokinetic as well as chemotactic activity for equine polymorphonuclear leucocytes. Although parasite derived chemotactic activity could be appreciated at high protein inputs, such leucotactic activity was quickly lost upon dilution. In contrast chemokinetic activity was readily observed in saline extracts over a much broader range of protein inputs. Utilizing the Zigmond‐Hirsch checkerboard assay the chemokinetic properties in the saline extracts were more pronounced when chemokinetic factors were loaded into the cell compartment of the chemotactic chambers only. Mild heat treatment or storage at 4°C resulted in little destruction of the chemokinetic factors. However six cycles of rapid freezing and thawing generated marked increases in chemokinetic activity and not chemotactic activity. The results of this work provide for the first time evidence of parasite derived chemokinetic factors.
Murine alloantigen acquisition by schistosomula of Schistosoma mansoni: Further evidence for the presence of K, D, and I region gene products on the tegumental surface
Authors: GITTER B. D. , DAMIAN R. T.
Published: October 2007

Previous studies have demonstrated that shistosomula, recovered from the lungs of Schistosoma mansoni‐infected mice, acquire H‐2Kk and both Ik and Is gene products. We confirmed and extended those observations by identifying several individual antigenic specificities mapping not only to H‐2Kk and I‐Ak (Sher, Hall & Vadas 1978), but to H‐2Dk, I‐Ek, H‐2Kb, H‐2Db and I‐Ab as well. Private H‐2 specificites 23 (H‐2Kk) and 32 (H‐2Dk) were identified on the tegumental surface of schistosomula isolated from C3H/Crgl mice (H‐2k). Larvae isolated from C57Bl/10Sn (B10) mice (H‐2b) were shown to acquire private specificities 33 and 2, which map to H‐2Kb and H‐2Db respectively. I region associated (Ia) antigens coded for by genes mapping in the I‐A subregion (Ia. 2 and 3) and I‐E subregion (Ia. 7) were also acquired from C3H/Crgl mice. Schistosomula from B10 donors were shown to acquire Ia specificities 3 and 8, which are under I‐A subregion control. Evidence that monoclonal antibodies recognize H‐2 antigens on the larval surface is also demonstrated.
Immune mechanisms in C57B1 mice genetically resistant to Trypanosoma congolense infection. I. Effects of immune modulation
Authors: WHITELAW D. D. , MACASKILL J. A. , HOLMES P. H. , JENNINGS F. W. , URQUHART G. M.
Published: October 2007

Summary The effect of immune modulation on the pattern and course of infection with T. congolense was investigated in a strain of mice (C57B1) which is known to possess a significant degree of trypanotolerance, and a susceptible strain (CFLP) which rapidly succumbs to infection. Immunosuppression of C57B1 mice by splenectomy, cyclophosphamide treatment or gamma irradiation reduced their survival to near that of susceptible strains of mice. In contrast, attempts to enhance the immune response of susceptible CFLP mice using either a variety of immunostimulants, simultaneous vaccination with irradiated parasites at the time of infection, passive immunization or reducing the number of parasites used for infection, failed to confer a level of protection comparable to that of C57B1 mice. It was concluded that the basis of trypanotolerance, although immunological in nature, is associated with, as yet, undetermined factors.
The primary humoral immune response of European green lizards (Lacerta viridis) to Leishmania agamae
Authors: INGRAM G. A. , MOLYNEUX D. H.
Published: October 2007

Summary European green lizards, Lacerta viridis, produced relatively thermostable, dithiothreitol‐sensitive, non‐precipitating, agglutinins and complement‐fixing antibodies (CFA) to Leishmania agamae administered subcutaneously (SC), intraperitoneally (IP) or orally (OR). Antibodies were also detected by the immobilization test (IMM) and by enzyme‐linked immunosorbent assay (ELISA). The most sensitive method for the detection of stimulated immunoglobulins was ELISA. Antibodies were detected as early as 3 days post‐infection with ELISA and between 5 and 7 for CFA, direct agglutination (DA) and indirect haemagglutination (IHA). In the case of IMM, the times of first detection varied from 14 to 28 days. Maximum CFA (2‐8), DA (2‐8), IHA (2‐11) and ELISA (2‐16) titres were reached from 42 to 49 days with significantly higher values occurring in the OR and IP groups. With IMM, maxima occurred after 5 or 6 weeks. Following exposure, two‐ to five‐fold significant increases in serum lysozyme levels were demonstrated but the concentrations in sera following SC, IP or OR routes of antigen administration were not significantly different when the groups were compared with each other. The highest lysozyme values (approximately 12.3–12.5 μgml‐1) were found in the SC and OR groups when compared to the IP(7.40 μgml‐1).
Antilymphocyte autoantibody in lethal mouse malaria and its suppression by non‐lethal malaria
Authors: SOUZA J.B. DE , PLAYFAIR J.H.L.
Published: October 2007

Summary Mice infected with lethal P. berghei or P. yoelii malaria develop anti‐lymphocyte autoantibodies less than a week after infection. The autoantibodies are IgM, T‐dependent and cytotoxic to a subpopulation of non‐T lymphocytes at 37°C in the presence of mouse or guinea‐pig complement. Non‐lethal P. yoelii and P. chabaudi do not induce these autoantibodies. X‐irradiated P. berghei parasites induce autoantibodies in normal mice but not in mice infected with non‐lethal P. yoelii suggesting an active suppressor mechanism in the non‐lethal infection.
Passive transfer of immunity against hepatic amoebiasis in the hamster by cells
Authors: GHADIRIAN E. , MEEROVITCH E.
Published: October 2007

Summary The role of passive cell‐mediated transfer of immunity in hepatic amoebiasis in hamsters was studied. The transfer of peritoneal cells from hamsters vaccinated against or protected from hepatic amoebiasis and from those with hepatic amoebiasis, as well as of spleen cells from vaccinated or protected, but not from infected hamsters, conferred immunity against hepatic amoebiasis in recipient normal hamsters. Treatment of the spleen cells from protected hamsters with anti T‐cell serum abolished their ability to transfer immunity. It appears that the effector mechanism in this system is T‐cell dependent.
Mechanisms of protective immunity against Schistosoma mansoni infection in mice vaccinated with irradiated cercariae III. Identification of a mouse strain, P/N, that fails to respond to vaccination
Authors: JAMES STEPHANIE L. , SHER A.
Published: October 2007

Summary Eleven strains of inbred mice were examined for their ability to develop resistance to challenge Schistosoma mansoni infection as a result of previous exposure to homologous cercariae that had been attenuated by high‐dose irradiation. Two strains, C57B1/6J and BALB/c, demonstrated consistently high levels of vaccine‐induced immunity (means of 64% and 58% resistance, respectively, when compared to control groups of the same strain) and were designated as ‘high responder’ strains to vaccination. Six other strains fell into an intermediate category, demonstrating moderate, yet statistically significant, levels of immunity resulting from vaccination (means of 30–50% resistance). Only one of the strains examined consistently failed to respond to vaccination by the development of significant levels of immunity to challenge infection. Animals of the P/N strain demonstrated a mean of only 15% resistance to challenge in five experiments and have been classified as ‘low responders’ to vaccination. P/N mice have previously been characterized as deficient in their ability to mount delayed hypersensitivity reactions, produce lymphokine and display macrophage activation for cytolysis of extracellular and intracellular targets in other experimental systems, suggesting that these immune responses may be critical to the establishment of vaccine‐induced resistance to S. mansoni infection. The availability of high and low responder mouse strains should facilitate a genetic approach to characterization of the immune effector mechanism(s) of vaccine‐induced resistance to S. mansoni infection.
Surface proteins of a filarial nematode: a major soluble antigen and a host component on the cuticle of Litomosoides carinii
Authors: PHILIPP M. , WORMS M. J. , McLAREN DIANE J. , M. OGILVIE BRIDGET , PARKHOUSE R.M. , TAYLOR PATRICIA M.
Published: October 2007

Summary The surface composition of three stages in the life cycle of Litomosoides carinii, a filarial parasite of rodents, has been studied using radio‐iodination techniques. Confirmation that radiolabeled components were confined to the parasite surface was achieved using light and electron microscope autoradiography. Biochemical analysis of extracts of radiolabeled parasites by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS‐PAGE) revealed that one major component (mol. wt. 55000) could be solubilized with the aid of detergents. This component, which was present on male and female adult worms and on post‐parasitic third stage larvae, accounted for about one‐third of the total proteins available for surface iodination, and was antigenic in infected hosts. The remaining surface components could be solubilized only with urea and SDS under reducing conditions. The 55 000 mol. wt. surface antigens of male and female adult worms exhibited identical two‐dimensional tryptic maps, but the similar 55 000 mol.wt. antigen of post‐parasitic third stage larvae was different. There was, however, some sharing of antigenic determinants between adult and larval surface components. The principal protein present in detergent extracts of surface‐radio‐labelled blood microfilariae was host serum albumin.
Non‐specific potentiation of T‐ and B‐lymphocyte proliferation at the early stage of infection by Schistosoma mansoni: role of factors secreted by the larvae
Authors: AURIAULT C. , DESSAINT J.P. , MAZINGUE CHRISTINE , LOYENS ANNE , CAPRON A.
Published: October 2007

Summary The response of rat lymphocytes to schistosomula released products (SRP) was examined. SRP non‐specifically activated lymphocytes by potentiating their proliferative response to PHA, Con A or LPS. The parasite factor involved was dialysable and heat stable. The addition of SRP to cultures containing nylon‐wool non‐adherent lymph node cells resulted in a significant enhancement of cell proliferation. The effect of SRP on athymic nude (Nu/Nu) and litter mate (Nu/+) control rat cells indicated an effect on the proliferation of both B and T lymphocytes. SRP acted in a dose‐dependent manner and its action was observed as early as the beginning of cell division. This corresponds to the in vivo situation, since at the early stage of infection increased proliferative responses of the lymph node cells to mitogens were observed. The adjuvant effect of SRP could partly explain the regulation of the cellular immune response observed during S. mansoni infection by the parasite itself and could represent one of the mechanisms involved in immunity to reinfection that is under the control of the parasite.
Trypanosoma cruzi variants with reduced virulence obtained by mutagenesis
Authors: MARCHAND MARTINE , BOON T.
Published: October 2007

Summary Previous reports have indicated that by mutagen treatment of mouse tumour cells in vitro it is possible to obtain at high frequency stable tumour cell variants that fail to form tumours in syngeneic mice because of increased immunogenicity. By analogy with these tumour cell variants, we examined whether variants with reduced virulence could be obtained by mutagen treatment of trypomastigotes derived from a Trypanosoma cruzi strain that was adapted to culture and produced lethal infections in DBA/2 mice at a dose of 5 × 104 parasites. A very large frequency of T. cruzi clones were obtained that failed to provoke an acute lethal infection after injection of 5 × 105 parasites. Most of these variants with reduced virulence (vir‐) multiplied actively in normal mice until day 8 after injection. After that time the parasitaemia decreased gradually. For most variants a low level of residual parasitaemia persisted for more than 100 days. Unlike the situation encountered with mouse tumour cell variants it was not possible to demonstrate the presence of new antigens on the T. cruzi vir‐ variants. However, these variants seemed to have acquired an increased immunogenicity since they provoked the rejection of virulent parasites injected concomitantly. Mice that had been immunized with living vir‐ clones were protected against a challenge with a virulent clone derived from the original parasite population.