bluuebunny/crossref_metadata_2025 huggingface dataset:
The interaction of human T‐lymphocytes and Entamoeba histolytica: killing of virulent amoebae by lectin‐dependent lymphocytes
Authors: SALATA ROBERT A. , COX JOANNA G. , RAVDIN JONATHAN I.
Published: October 2007

Summary Clinical and experimental studies indicate that following invasive disease due to Entamoeba histolytica, development of human cell‐mediated immune mechanisms may provide protective immunity. Activated, human monocyte‐derived macrophages in vitro can kill virulent axaenic amoebic trophozoites. This study describes the interaction of lectin‐stimulated T‐lymphocytes and E. histolytica trophozoites (virulent strain HM1‐IMSS). Amoebae progressively killed unstimulated nonimmune T‐lymphocytes over 18 h incubation with no effect on amoebic viability. T‐lymphocytes, stimulated with phytohaemagglutinin (PHA), were progressively cytotoxic for virulent HMI amoebae over 18 h incubation, but were also reduced in viability themselves. Lymphocyte cytotoxicity for amoebae was absent if PHA was removed before or added only during the assay. PHA‐stimulated T‐lymphocytes killed amoebae at cell ratios of lymphocytes to amoebae as low as 50:1 and cytotoxicity was antibody‐independent. PHA‐stimulated T‐lymphocytes, depleted of T8‐bearing cells by complement‐mediated lysis, were unable to kill amoebae. Adherence of PHA‐stimulated T‐lymphocytes to amoebae was greater than with unstimulated T‐lymphocytes. Inhibition of the amoebic adherence lectin with N‐acetyl‐D‐galactosamine decreased lymphocyte‐amoebic adherence and resulted in increased lymphocyte amoebicidal activity and lymphocyte survival. Suspension of amoebae with or without adherent PHA‐stimulated T‐lymphocytes in a 10% dextran solution indicated that cytotoxicity was contact dependent. In summary, PHA‐stimulated T‐lymphocytes of the T8‐phenotype can kill virulent axaenic E. histolytica trophozoites through a contact‐dependent, antibody‐independent mechanism.
The production of reactive oxygen species in mice infected or immunized with Plasmodium berghei
Authors: LI M. , LI Y. J.
Published: October 2007

Summary The capacity of peritoneal exudate cells (PEC) obtained from mice infected or immunized with Plasmodium berghei to produce reactive oxygen species (ROS) and the biological basis of this response was investigated, using luminol‐dependent zymosan‐triggered chemiluminescence (CL). CL response of PEC from infected mice increased at the early stage but was significantly depressed at the later course of the infection. A similar biphasic activity of peroxidase was also observed in PEC from infected mice. On the other hand, PEC from immunized mice exhibited concomitant increases of the ability to produce CL, the activity of peroxidase and the expression of Fc and C3 receptors on cell surface. Compared with the controls, PEC from immunized mice showed an elevated background CL, responded more rapidly to the stimulation and generated considerably higher CL when triggered with opsonized zymosan. The data suggest that phagocytes in immunized mice are active in the production of ROS while those in infected mice are less active, and the inhibition of the ability of phagocytes to produce ROS may be one of the mechanisms for the parasites to escape from host immune system.
Target antigens of malaria transmission blocking immunity exist as a stable membrane bound complex
Authors: KUMAR NIRBHAY
Published: October 2007

Summary Monoclonal antibodies (MoAbs) blocking transmission of malaria by blocking fertilization of female gametes by male gametes in the mosquito midgut immunoprecipitate three polypeptides (apparent non‐reduced mol. wt of 230000, 48000, 45000) from the surface of gametes and zygotes of Plasmodium gallinaceum and P. falciparum. Earlier studies have shown that the epitopes with which the MoAbs react are present only on the mol. wt 230000 polypeptide in P. gallinaceum and the 48 000/45 000 mol. wt antigens in P. falciparum (Kumar 1985, Vermeulen et al. 1985). In gel permeation chromatography all three polypeptides were found to be co‐eluted. Cross‐linking reagents were used to cross‐link proteins on the intact cells and in the soluble extracts. The cross‐linked product immunoprecipitated by the MoAbs showed an approximate mol. wt of 290000 to 300000, suggesting a stoichiometry of 1:1 between the high and low mol. wt polypeptides. Evidence was also obtained for the existence of a subpopulation of the 48 000/45 000 mol. wt polypeptides which is not complexed with the 230 000 mol. wt polypeptide. These data indicate that the 230 000 polypeptide is physically associated with the 48 000 and 45 000 polypeptides; the high and low molecular weight polypeptides appear to exist in a stable membrane bound complex.
Isolation and characterization of salivary antigens from the female tick, Dermacentor andersoni
Authors: GORDON J. R. , ALLEN J. R.
Published: October 2007

Summary The salivary glands of ixodid ticks are complex organs which are known to contain the antigens responsible for tick resistance in animals. We have identified a large number of proteins from salivary gland extracts (SGE)*, at least some of which are immunologically recognized by tick resistant animals and which are therefore presumed to be secreted salivary components. During the 6 to 10 day feeding process, a number of these antigens alter in concentration according to individual kinetics, and some of these changes correlate with the kinetics of skin test reactivity of SGE obtained at different times throughout the feeding period. By use of immunoaffinity chromatography we have isolated large quantities of many of the salivary antigens (SGA) contained in SGE, and found that they contain several esterase activities. SGA stimulates both immediate and delayed skin reactions in tick resistant guinea‐pigs, and these reactions are about 200‐fold more intense, per unit protein, than those elicited by SGE. The skin reactions to SGA are basophil‐mediated and have many features in common with the cutaneous basophil hypersensitivity reactions of tick resistant animals. The demonstrated antigenic complexity of the glands may have profound implications for attempts to develop anti‐tick vaccines, as it may eventually be found that candidate vaccines will have to incorporate more than one tick antigen in order to be effective.
Monoclonal antibodies that distinguish Trypanosoma congolense, T. vivax and T. brucei
Authors: NANTULYA V. M. , MUSOKE A. J. , RURANGIRWA F. R. , SAIGAR N. , MINJA S. H.
Published: October 2007

Summary Monoclonal antibodies (MoAbs) were derived against in‐vitro‐propagated procyclic forms of Trypanosoma congolense, T. vivax, T. brucei brucei and T. b. rhodesiense in order to identify antigens for use in immunodiagnosis of African trypanosomiasis. The antibodies have been tested against procyclic and bloodstream form trypanosomes of 13 T. congolense, six T. vivax six T. b. brucei, four T. b. rhodesiense, five T. b. gambiense and three T. simiae isolates from different geographical areas by indirect immunofluorescent antibody test (IFAT) and enzyme‐linked immunosorbent assay (ELISA). The MoAbs raised against T. b. brucei reacted with all the brucei group of trypanosomes but not with T. congolense, T. simiae or T. vivax. Likewise, MoAbs against T. congolense reacted with T. congolense and T. simiae but not with any of the other species, while those against T. vivax reacted with T. vivax only. The antigens recognized by these MoAbs were present in lysates of bloodstream trypanosomes as well as midgut (for T. congolense and T. brucei) and epimastigote forms from infected Glossina morsitans centralis. There was no reactivity of the MoAbs with Theileria parva, Anaplasma marginale, Babesia bigemina or Plasmodium falciparum. These antibodies and the antigens they recognize should, therefore, prove useful in the development of assay systems for immunodiagnosis of African trypanosomiasis.
Trichinella spiralis: Intestinal expression of systemic stage‐specific immunity to newborn larvae
Authors: WANG CHING HUA , BELL R. G.
Published: October 2007

Summary Rats immunized with newborn Trichinella spiralis larvae i.v. were found to confer a specific anti‐newborn larvae immunity in the small intestine. In rats immunized with newborn larvae i. v. and then challenged with adult worms intraintestinally, total newborn larvae recovery was reduced by 75–90% in thoracic duct lymph and in hepatic portal vein blood. No newborn larvae were found in the peritoneal fluid of immunized rats. In addition to an absolute reduction in number, larval migration from the small intestine to the thoracic duct was delayed by 6–12 h and migration to the portal vein was inhibited for at least 8 h. The establishment of adult worms in the small intestine and female worm fecundity were not affected by anti‐newborn larvae immunity. Identical quantitative effects on newborn larvae migration from the small intestine were achieved by homologous transfer of anti‐newborn larvae immune serum i. v. into naive recipient rats.
Evaluation of T‐cell subsets in the lesion infiltrates of human cutaneous and mucocutaneous leishmaniasis
Authors: BARRAL ALDINA , JESUS AMÉLIA R. , ALMEIDA R. P. , CARVALHO E. M. , BARRAL‐NETTO M. , COSTA J. M. L. , BADARO R. , ROCHA H. , JOHNSON W. D.
Published: October 2007

Summary We have characterized the T‐lymphocytes in the skin lesions of 10 patients with cutaneous leishmaniasis and in the nasal lesions of seven patients with mucosal leishmaniasis. with the immunoperoxidase and monoclonal antibody techniques. There was predominance of cells with helper phenotype (Leu 3A + 3B) over suppressor phenotype (Leu 2a) in the lesions of both groups. The helper/suppressor (H/S) ratio in the skin lesions was 1±6 ± 0±5 and in the nasal lesions of mucosal leishmaniasis was 1±7 ± 0±8. The H/S ratios in the peripheral blood of patients with cutaneous leishmaniasis (2±1 ± 0±8) and in patients with mucosal leishmaniasis (1±6 ± 0±8) were comparable and similar to the ratios in the skin and nasal biopsies. The percentage of T‐cells and macrophages expressing the Dr antigen in the cutaneous group (69±5 ± 13±7) was not significantly different from the mucosal patients (90±3 ± 5±7). We conclude that the immunopathology of the skin lesions in cutaneous leishmaniasis is similar to the nasal lesions of mucosal leishmaniasis.
Schistosoma mansoni: autoradiographic tracking studies of isotopically‐labelled challenge parasites in naive and vaccinated CBA/Ca mice
Authors: KAMIYA H. , SMITHERS S. R. , MCLAREN DIANE J.
Published: October 2007

Summary The migration of isotopically‐labelled challenge parasites of Schistosoma mansoni in naive CBA/Ca mice, and CBA/Ca mice vaccinated 4 weeks previously with about 600 radiation‐attenuated cercariae, has been followed by means of compressed organ autoradiography. In naive mice, only 16% of the challenge parasites failed to migrate from the skin to the lungs, whereas up to half of the individuals that succeeded in reaching the pulmonary vasculature did not move on to the liver. The tracking technique thus revealed a total loss of 58% of the challenge parasites, which correlated well with the fact that only 50% of the challenge was recovered as adult worms by retrograde perfusion of the hepatic portal system. Challenge migration in vaccinated mice initially proceeded more slowly than in naive mice, but peak numbers of foci were eventually recorded in the lungs on the same day in both groups of individuals. We did not therefore recognize a delay in parasite migration in vaccinated mice. In the present experiments, 58±5% of the challenge failed to reach the lungs of vaccinated rodents, and 25% of those parasites that did attain the pulmonary vasculature were not recruited to the liver. The tracking technique thus accounted for a total loss of 83±5% of the parasites, which again correlated well with the fact that we recovered only 22% of the challenge as adult worms at portal perfusion. The data presented here prove conclusively that the major phase of immune‐dependent challenge elimination in vaccinated CBA/Ca mice occurs in the cutaneous tissues, and that only a small proportion of the parasites are lost in the lungs. These data are entirely consistent with those we have published elsewhere for the CBA/Ca mouse using a multiplicity of different techniques; they differ however, from results reported by others for the C57 Black strain of mouse. Possible reasons for these discrepancies are discussed.
Plasmodium chabaudi: a rodent malaria model for in‐vivo and in‐vitro cytoadherence of malaria parasites in the absence of knobs
Authors: COX J. , SEMOFF S. , HOMMEL M.
Published: October 2007

Summary The ability of Plasmodium chabaudi infected erythrocytes to bind to endothelial cells in vivo and to various murine cell lines in vitro is described. A procedure for the selective recovery of a sequestering subpopulation of schizont‐infected erythrocytes from hepatic sinusoids of BALB/c mice, using a combination of body perfusion, trypsin treatment and Percoll density centrifugation was developed. The serial subinoculation of such a subpopulation was used to select for a clone of parasites (strain AJJ) with considerably better cytoadherent characteristics than the parent line (strain AJ). In contrast, it was demonstrated that another clone (PC7), showed no cytoadherence in vivo or in vitro. This study shows that parasite induced alterations occurred on the surface of erythrocytes infected with late developmental stages of P. chabaudi. The antigenicity of these molecules in the infected mouse was demonstrated using immune serum and affinity chromatography. Cytoadherence and surface antigenic changes in P. chabaudi schizont‐infected erythrocytes were demonstrated in the absence of the submembranous ‘knobs’ associated with cytoadherence in P. falciparum.
Cytotoxic T‐cells elicited in cattle challenged withTheileria parva(Muguga): evidence for restriction by class I MHC determinants and parasite strain specificity
Authors: MORRISON W. I. , GODDEERIS B. M. , TEALE A. J. , GROOCOCK C. M. , KEMP S. J. , STAGG D. A.
Published: October 2007

SummaryThe MHC restriction and parasite strain specificity of cytotoxic cells elicited in a group ofTheileria parva(Muguga)‐immunized cattle following homologous challenge, were investigated. The cytotoxic cells were specific for parasitized target cells and in 9 of the 10 animals examined, they were clearly genetically restricted. Cytotoxicity could be inhibited by monoclonal antibodies (MoAb) to class I MHC molecules but not by MoAb to class II molecules, indicating that a large component of the response was restricted by class I MHC determinants. Low levels of inhibition of cytotoxicity were also obtained with a MoAb to the T‐cell subset marker BoT8, suggesting that at least part of the response was mediated by BoT8+lymphocytes. When cytotoxic cells from individual cattle were assayed on panels of parasitized target cells, there was a close correlation between susceptibility of the target cells to lysis and sharing of BoLA‐A locus‐encoded specificities with the effectors. This observation, taken together with the knowledge that within several of the sets of BoLA‐A‐matched targets the relevant BoLA‐A specificities were on different MHC haplotypes, indicated that the responses were restricted predominantly by BoLA‐A products.

In individual cattle there was a striking bias in the restriction of the response to one or other BoLA‐A specificity. Among the six specificities represented, responses restricted by w6, w8 and KN18 consistently predominated over responses restricted by w7, w10 and w11. In the three cattle tested for parasite strain specificity, two showed complete specificity and one partial specificity for cells infected with the parasite stock used for immunization,T. parva(Muguga).
Macrophage procoagulant activity in experimental African trypanosomiasis
Authors: ROSSI BARTIRA C. , DEAN ROGER T. , TERRY ROLAND J.
Published: October 2007

Summary Peritoneal macrophages from mice infected with Trypanosoma brucei brucei expressed a greatly elevated procoagulant activity (PCA) which could be reversed to normal levels after trypanocidal therapy. Comparison with infection caused by the non‐pathogenic T. musculi suggested that the level of PCA related to parasite pathogenicity. Unstimulated macrophages, which generate only slight PCA upon stimulation with zymosan, become hyperresponsive to this stimulus during the course of infection. Hyperresponsiveness is not a generalized feature of these cells during infection, as they become progressively hyporesponsive to the same stimulus in terms of lysosomal enzyme secretion. We were unable to demonstrate a direct role of the trypanosomes in macrophage activation; however, artificial removal of the glycoprotein coat rendered the parasites highly stimulatory for macrophages even in the absence of opsonins. These results suggest that the parasites may activate macrophages indirectly, and that the resulting elevated PCA may play a role in the abnormal blood coagulation known to occur in this disease.
T‐lymphocyte requirement for the induction of mouse macrophage procoagulant activity by Trypanosoma brucei
Authors: ROSSI BARTIRA C. , DEAN ROGER T. , TERRY ROLAND J.
Published: October 2007

Summary We have previously shown that peritoneal macrophages from Trypanosoma brucei infected mice, but not from uninfected mice, expressed high levels of procoagulant activity that could not be produced in vitro by incubation of unstimulated macrophages with bloodstream forms of trypanosomes. In the present study we demonstrate that trypanosome‐induced macrophage activation can be achieved in vitro by providing either sensitized (day 7 of infection) lymphocytes and trypanosomes or the supernatant fluid from this interaction. The ability of lymphocytes to secrete macrophage‐activating lymphokines is enhanced up to day 12 of infection but was absent in the later stages. Although enhancement of the procoagulant activity occurred in infected nude mice, it seems that macrophage function in African trypanosomiasis, as regards the expression of procoagulant activity, is regulated by T‐lymphocytes.
Anti‐idiotypic antibodies: preparation and identification; application to the detection of antigens of Plasmodium falciparum
Authors: ZHOU WEISHENG , LI YINGJIE
Published: October 2007

Summary Anti‐idiotypic antibodies (anti 94D1 Id and anti 94C3Id) were prepared by immunizing rabbits with designated monoclonal antibodies (MoAb) 94D1MoAb (94D1Id) and 94C3MoAb (94C3Id) specific for Plasmodium falciparum. The specificity of both was directed against idiotypes of the relevant MoAb. The interaction between 94D1Id and anti94D1Id or 94C3Id and anti94C31d was almost completely inhibited when sufficient concentration of P. falciparum antigen was added, suggesting that the idiotypes recognized by anti‐94D1Id or anti94C3Id were located in the antigen binding site of the MoAbs or the construction of the V region of anti‐idiotypic antibodies may be similiar to that of P. falciparum antigenic determinants combining with MoAb. Each 4i assay (inhibition of idiotype‐anti‐idiotype interaction) had a different specificity and sensitivity in detecting P. falciparum asexual antigens. The 94C3Id‐anti94C3Id system detected a minimal level of 0±001% parasitaemia and did not cross‐react with other species, suggesting that 94C3Id‐anti94C3Id system is species specific and may become a valuable tool for immunodiagnosis.
Impaired natural defence of beige (Chediak‐Higashi syndrome) mice against tissue‐migrating larvae of Strongyloides ratti and its reconstitution by bone marrow cells
Authors: NAWA Y. , ABE T. , IMAI J. , MARUYAMA H.
Published: October 2007

Summary The susceptibility of C57BL/6‐bgJ/bgJ mice, which exhibit a murine counterpart of the Chediak‐Higashi syndrome, to infection with Strongyloides ratti was examined. After a primary infection, the peak of the daily larval output in faeces (LPG) of bgJbgJ mice was approximately twice as high as that of their littermate bgJ/+ mice. The total number of tissue migrating larvae recovered from bgJ/bgJ mice at 36 h after infection was also approximately twice as high as that from bgJ+mice. However, after a primary infection, bgJ/bgJ mice could completely expel adult worms in the intestine by day 14. When an equal number of tissue migrating larvae obtained from the head of +/+ mice were implanted into bgJ/bgJ and bgJ/+ mice, the magnitude and the kinetics of LPG were comparable between them, indicating that in both groups implanted larvae established in the intestine lo become adult worms and then they were expelled by day 13. Thus, immune mechanisms involved in worm expulsion of bgJ/bgJ mice were comparable to those of bgJ/+mice. The higher susceptibility of bgJ/bgJ mice could be reduced to the level of bgJ/+ mice by bone marrow grafting from bgJ/+mice 6 weeks prior to infection. Furthermore, when lethally irradiated bgJ/bgJ mice or bgJ/+mice were reconstituted with either type of bone marrow cells, the mice given bgJ/bgJ bone marrow cells showed higher susceptibility to infection with S. ratti regardless of the genotype of the recipients. These results indicate that the impaired natural defence of bgJ/bgJ mice is predetermined at the level of haemopoietic stem cells.
T‐cell‐dependent eosinophilia in the cerebrospinal fluid of the mouse infected with Angiostrongylus cantonensis
Authors: SUGAYA HIROKO , YOSHIMURA KENTARO
Published: October 2007

Summary Eosinophilia of the cerebrospinai fluid (CSF) in permissive (rats) and non‐permissive (mice) hosts infected with Angiostrongylus cantonensis, and the possible mechanism of the eosinophilia were studied. In three strains of thymic mice (ICR, ddY and BALB/c), the infection provoked a marked CSF eosinophilia starting at around day 12, reaching a peak level at day 20 and maintaining significantly high levels until day 35, In contrast, in athymic nude mice of BALB/c strain the infection failed to evoke this eosinophilia, suggesting T‐ceil dependence of murine CSF eosinophilia. Humoral antibodies did not correlate with the induction of eosinophilia. A time‐course study of worm recovery in the mouse brains indicated a gradual but consistent reduction in worm burden in accordance with the rapid rise in CSF eosinophil levels. Bone marrow eosinophilia occurred in mice at day 5, which preceded CSF eosinophilia. Jirds. a permissive but less susceptible host, developed a CSF eosinophilia with a peak level at day 17, but which declined rapidly following the peak. Permissive rat hosts developed significant peripheral and bone marrow eosinophilia at day 35 but their CSF eosinophilia was markedly less prominent than that of mice and jirds. These data clearly indicate that there are distinct differences in the mechanism of eosinophilia and eosinophilia‐inducing factors between permissive and non‐permissive hosts.
Excretory/secretory antigen of Toxocara canis: recognition profiles of polyclonal and larvicidal monoclonal antibodies
Authors: DEL AGUILA C. , CUELLAR C. , GUILLÉN J.L.
Published: October 2007

Summary Five monoclonal antibodies against the excretory/secretory (E/S) antigen of Toxocara canis were obtained and characterized. Immunoprecipitating activity was demonstrated in an in‐vitro micropre‐cipitating assay using live T. canis larvae. Their capacity to kill larvae was also shown in an in‐vitro assay. Two zones of reactivity were observed in 7.5 and 12.5% SDS‐PAGE (177‐77 kD, 43‐15 kD) of immunoprecipitates of human and mouse positive polyclonal anlisera. The murine monoclonal antibodies showed a common pattern of reactivity with the proteins in the 177‐77 kD range.
Echinococcus multilocularis: the non‐specific binding of different species of immunoglobulins to alveolar hydatid cysts grown in vivo and in vitro
Authors: ALKARMI T. O. , ALSHAKARCHI Z. , BEHBEHANI K.
Published: October 2007

Summary Alveolar hydatid cysts (AHC) were isolated from C57BL/6J and BALB/c mice al 8 and 12 weeks post‐infection from subcutaneous and intraperitoneal foci and cultured in in vitro. Freshly isolated as well as in vitro‐grown cysts were incubated with Fc or F(ab')2 fragments of human, rabbit, mouse, goat or sheep immunoglobulins, then washed and incubated with a fluorescein‐conjugated rabbit or goat F(ab')2 fraction of antisera to each of the above primary sera. Significant fluorescence on the surface of AHC was detected when they were incubated with human, rabbit or mouse Fc fractions followed by the addition of goat or rabbit fluorescein‐conjugated antiserum. No fluorescence was detected when the AHC were incubated with the F(ab')2 fragments and fluorescein‐conjugated antiserum, except when the primary antiserum was mouse F(ab')2 fractions. Cysts grown in vitro retained their binding ability to human, rabbit or mouse Fc fractions. However, the intensity of fluorescence decreased proportionally with lime. The maximum intensity of staining was observed with small cysts. Large cysts showed diminished fluorescence. The non‐specific binding of human, mouse or rabbit immunoglobulins (Fc fractions) to AHC was also confirmed by rosetting with sheep erythrocytes (SRBC) which suggests that the larvae of Echinococcus multilocularis may utilize the presence of Fc receptors on their surface in order to elude immune destruction by the host.
Eitneria tenella: immunological diversity between asexual generations
Authors: MCDONALD V. , WISHER M. H. , ROSE M. ELAINE , JEFFERS T. K.
Published: October 2007

Summary In the development of a normal strain, WIS, of Eimeria tenella there are three generations of schizogony whereas in an attenuated line, WIS‐F‐96, derived from WIS, the second and third are absent. Chickens immunized by infection with WIS‐F‐96, however, were highly resistant to oral challenge with sporulated oocysts of WIS, and histological studies indicated that the immune response was directed against the sporozoites from that challenge inoculum. When challenge of the WIS‐F‐96‐primed chickens consisted of second generation merozoites of WIS (inoculated intracaecally), immunity was less pronounced and the histological data indicated that the merozoites proceeded to develop normally in these birds. These indications of immunological diversity between the merozoites of the first and second generations of schizogony of E. tenella WIS correlated with the results of preliminary studies of the antigenic composition of these developmental stages.
Western blot analysis of reactivity to larval and adult Strongyloides ratti antigens in mice
Authors: NORTHERN CAROLYN , GROVE DAVID I.
Published: October 2007

Summary Mice were infected once, twice or many times with Strongyloides ratti infective larvae, and the parasite was allowed to complete its development. Other mice were infected many times with either infective larvae only, by aborting the infection with cambendazole. or with adult worms transferred by intraoesophageal intubation. Sera from these animals were analysed by immunoblotting against SDS‐PAGE separations of larval and adult worm water‐soluble, deoxycholate‐soluble, sodium dodecyl sulphate‐soluble and excretory/secretory antigens. Minimal antibody responses were observed after primary and secondary infections. Mice exposed to multiple complete infections reacted strongly to both larval and adult antigens but greater responses were observed against the larval preparations. Stage‐specific effects were noted in mice infected with larvae only or adult worms only. Mice exposed only to larvae reacted with larval antigens and to a minor degree to somatic adult worm antigens while those mice which were exposed only to adult worms failed to react with any of the antigen preparations. Some cross‐reactions were found, however, as mice infected only with larvae displayed strong reactions against both larva] and adult excretory/secretory products. These data demonstrate differences in sero‐reactivity to infective larvae and adult worms and suggest that humoral immunity is induced by larvae migrating through the tissues and not by adult worms in the gut.
Molecular and serological characteristics of the glutathione S‐transferases of Schistosoma japonicum and Schistosoma mansoni
Authors: TIU WILFRED U. , DAVERN KATHY M. , WRIGHT MARK D. , BOARD PHILLIP G. , MITCHELL GRAHAM F.
Published: October 2007

Summary When aqueous extracts of Schistosoma japonicum and S. mansoni adult worms are passed over columns of glutathione‐conjugated agarose, two molecular species of Mr 26000 and Mr 28000 are detected in eluates as analysed by SDS‐PAGE, these eluates having glutathione S‐transferase (GST) activity. The molecules, termed Sj26 and Sj28 from S. japonicum and Sm26 and Sm28 from S. mansoni, can be immunogenic in rabbits or mice and appear not to be linked together as subunits of GST heterodimers. The elution profile of SjGST (Sj26 + Sj28) from glutathione columns resembles that of SmGST (Sm26 + Sm28) and, by peptide mapping, radioiodinated Sj26 and Sm26 are related as are the two Mr28000 molecules. Similarities between radioiodinated Sj2S and Sm28 are also obvious on two‐dimensional gel electrophoresis with some differences being observed between Sj26 and Sm26. The Mr28000 molecules are more prominent than the Mr 26000 molecules and, although Sj28 is a poor immunogen in mice, immunological cross‐reactivity between Sj28 and Sm28 is generally more readily detected than that between Sj26 and Sm26. Whether experimental vaccination against schistosomiasis japonica and schistosomiasis mansoni reported with cloned GSTs can be improved by incorporation of both Mr28000 and Mr 26000 species into the vaccine remains to be determined. On this point, the present data suggest that vaccination of mice with Sj26 plus Sm28 should be a useful means of increasing antibody responses to the GSTs of S. japonicum.
Characterization of epitopes on the 25 kD protein of the macrogametes/zygotes of Plasmodium falciparum
Authors: FRIES HELLA C. W. , LAMERS MARIEKE B. A. C. , SMITS MARI A. , PONNUDURAI THIVI , MEUWISSEN JOSEPH H. E. TH.
Published: October 2007

Summary A sexual stage–specific protein of Plasmodium falciparum with a Mr of 25 000 is one of the target antigens of transmission–blocking antibodies. The contributions of tertiary structure and post–translational modifications (glycosy–lation and acylation) to the structure of the epitopes on this protein were the subject of detailed investigations. After modification of the three–dimensional structure and modification or cleavage of carbohydrate groups and linked fatty acids, the immunological reactivity was investigated by three different techniques: (i) immunoprecipitation of radiolabeled proteins, (ii) enzyme–linked immunosorbent assay (ELISA), and (iii) Western blotting. The results of the experiments indicate that the immunological reactivity of the major epitopes on the 25 kD protein, including the epitope involved in transmission–blocking immunity, are dependent on the tertiary structure of the protein and on the presence of linked fatty acids, but not on the presence or absence of carbohydrate groups.
Schistosoma mansoni: migration and attrition of challenge parasites in naive rats and rats protected with vaccine serum
Authors: WARD ROSALIND E. M. , McLAREN DIANE J.
Published: October 2007

Summary The migration of isotopieally labelled Schistosoma mansoni challenge cercariae was monitored, by means of squashed organ autoradiography, in naive Spraguc–Dawley rats and rats protected with serum harvested from twice vaccinated donors. The majority of challenge larvae migrated from the skin to the lungs in both groups of rats, but a significantly increased number of larvae was retained in the lungs of serum recipients on day 8 post–challenge. An average of 25% of the challenge population succeeded in migrating to the livers of naive rats by day 14, compared to only 13% in passively protected animals; serum recipients were shown by perfusion on day 21 to be 73% immune. Histological examination of lung tissue harvested from naive rats challenged intravenously with lung–stage schistosomes revealed small foci composed of mononuclear cells that sometimes enclosed larvae; these worms are likely to be lost due to innate resistance. In the lungs of serum–protected rats, many challenge larvae were seen to be surrounded by extensive eosinophil–enriched inflammatory foci; parasite remnants were also observed within such reactions. Ultrastructural examination of worms recovered from the lungs of passively protected animals revealed muscle disruption and internal vacuolation, although the tegument remained intact. It is proposed that challenge attrition in serum–protected rats occurs essentially in the lungs and involves larval immobilization and subsequent death, perhaps mediated by cellular mechanisms.
Lack of interspecies barriers in anti–Id stimulated antibody production against Echinococcus granulosus antigens
Authors: CAROL HERNAN , HERNANDEZ ANA , BAZ ADRIANA , NIETO ALBERTO
Published: October 2007

Summary Polyclonal human anti–hydatid antibodies were affinity purified from a hydatid patient serum and used to produce a rabbit antiidiotype: serum. These anti–Id antibodies cross–reacted in ELISA with sera from 11 of 12 hydatid patients studied and with 13 infected or immunized mice sera. All mice primed and boosted with anti–Id produced anti–hydatid antibodies in the primary response and exhibited an increase in antibody titre after a booster injection. The same effect was observed with mice primed with antigen and boosted with anti–Id, although these mice exhibited higher antibody titres. A significant idiotype repertoire is shared by anti–hydatid antibodies produced by different individuals of the same or different species, and anti–Id raised against those antibodies behave as surrogate antigens producing a normal primary and secondary response in animals of different species from that used to isolate the Id.
Cell‐mediated immunity in localized cutaneous leishmaniasis patients before and after treatment with immunotherapy or chemotherapy
Authors: CASTES MARIANELLA , MOROS ZOILA , MARTINEZ AMALIA , TRUJILLO DINORAH , CASTELLANOS PEDRO LUIS , RONDON ANTONIO J. , CONVIT JACINTO
Published: October 2007

Summary In previous studies of the treatment of localized cutaneous leishmaniasis (LCL) we demonstrated that the therapeutic efficiency of immunotherapy (BCG plus promastigotes of Leishmania mexicana) is equal to that of chemotherapy (Glucantime), without causing the serious side‐effects of the drug treatment. In the present study, various aspects of cell‐mediated immunity, including the lymphoproliferative response in vitro to mitogens and Leishmania antigen, leishmanin skin test response, and leucocyte subpopulations were evaluated both before treatment and after cure in 39 LCL patients who had received immunotherapy (IT), in 34 submitted to chemotherapy (CT), and in 14 patients cured by the administration of BCG alone. We demonstrated evident signs of T‐cell activation in cured patients who had received either CT or IT. For example, an increased expression of IL‐2 receptors was observed in such patients, compared to their pretreatment values. Also, a significant percentage of patients showed augmented in‐vitro responses to mitogen, and both in‐vitro and in‐vivo reactivity to leishmanial antigen. No evidence was found for the development of an exaggerated immune response to Leishmania parasites in the IT group, because the final level of immunological reactivity was comparable to the CT group. Neither was there any difference in terms of the final immune response between the patients cured by BCG treatment alone and the other groups. However, the therapeutic efficiency of BCG was lower and the mean cure time was longer. We conclude that IT is very useful in the treatment of LCL patients because of its high efficiency, low propensity to produce side‐effects, and the fact that it does not induce a state of hyper‐reactivity.
Opsonization of yeast by the plasma of Biomphalaria glabrata (Gastropoda): a strain‐specific, time‐dependent process
Authors: FRYER SARAH E. , BAYNE CHRISTOPHER J.
Published: October 2007

Summary Phagocytosis of yeast by haemocytes of Biomphalaria glabrata, intermediate host of Schistosoma mansoni, is influenced strongly by host plasma components, although it can occur without involvement of such factors. Plasma from two strains of B. glabrata which are resistant to S. mansoni differs in its opsonic properties from the plasma of a susceptible strain. This may reflect the principles which determine compatibility or incompatibility in this host‐parasite system. Opsonization is a time‐dependent process: short periods of incubation in plasma from all strains reduces subsequent phagocytosis in the absence of plasma factors, whereas longer incubation in resistant strain plasma is markedly opsonic. Haemocytes from all strains examined are equally competent in their recognition of either native or opsonized yeast.
The action of a mast cell protease on the cuticular collagens of Necator americanus
Authors: McKEAN P. G. , PRITCHARD D. I.
Published: October 2007

Summary Collagen‐like proteins, thought to be responsible for maintaining the structural integrity of the nematode cuticle, were isolated from adult Necator americanus and shown to be susceptible to digestion by purified mast cell proteases. Although these collagens would appear normally to be masked by superficially expressed (surface) antigens, it is suggested that a sufficiently avid and specific immune response could remove this potentially protective coat, rendering the structurally important underlying layers open to immune attack.
Protective immunization of mice against Schistosoma mansoni with purified adult worm surface membranes
Authors: SMITHERS S. R. , HACKETT FIONA , ALI PIRLANTA OMER , SIMPSON A. J. G.
Published: October 2007

Summary Immunity to Schistosoma mansoni in the mouse was induced by vaccination with adult worm surface membrane (mb‐S). Of several adjuvants tested, including Freund's, BCG and alum, 50 μg of saponin per mouse given subcutaneously with the antigen was the easiest to administer, and gave consistent protection, approaching levels usually seen in our mouse model after exposure to irradiated cercariae. An antibody response to the schistosomular surface was detected in mice immunized with mb‐S plus saponin which was predominantly anti‐polypeptide, not anti‐carbohydrate, and thus similar to the antibody response of mice exposed to irradiated cercariae. The level of antibodies to Mr 90000 and 38000 schistosomular surface antigens as well as to Mr 25000 adult surface membrane antigen was significantly correlated with the presence of protection.
Specific detection of circulating surface/secreted glycoproteins of viable cysticerci in Taenia saginata cysticercosis
Authors: HARRISON L. J. S. , JOSHUA G. W. P. , WRIGHT S. H. , PARKHOUSE R. M. E.
Published: October 2007

Summary A mouse monoclonal antibody (MoAb), reactive with a repetitive carbohydrate epitope on lentil–lectin adherent glycoproteins present on the surface and in the secretions of Taenia saginata cysticerci, was used in the construction of a diagnostic ELISA assay to detect these glycoproteins in the serum of T. saginata infected cattle. The MoAb was used as the trapping layer and subsequently bound glycoprotein was revealed using the same MoAb and biotinylated peroxidase‐streptavidin complex as the developing system. The assay was suitably specific. Exceptionally low background values were obtained with sera from animals with a range of commonly occurring tropical parasitic infections, including Taenia hydatigena, Echinococcus granulosus and Fasciola gigantica. The minimal detection level was approximately 200 live cysticerci in cattle. Parasite derived glycoprotein could be detected in serum from about 4–5 weeks post‐infection onwards and was associated with a current infection, as drug treatment of infected cattle to kill the cysticerci resulted in the disappearance of these components from the circulation, while the titre of anti‐parasite antibody remained high. The same assay also detected Taenia solium cysticercosis in humans.
Susceptible mice present higher macrophage activation than resistant mice during infections with myotropic strains of Trypanosoma cruzi
Authors: RUSSO M. , STAROBINAS N. , RIBEIRO‐DOS‐SANTOS R. , MINOPRIO P. , EISEN H. , HONTEBEYRIE‐JOSKOWICZ M.
Published: October 2007

Summary The kinetics of macrophage activation were compared among inbred strains of mice (C3H, BALB, B6 and BIO.A) that are known to differ in their relative resistance to infections with the myotropic strains (Colombian and CL) of Trypanosoma cruzi. The parameters utilized to measure macrophage activation were rapid spreading on glass surfaces, hydrogen peroxide release and tumour necrosis factor/cachectin production. Macrophages obtained from C3H (susceptible), BALB (intermediate) and B6 or BIO.A (resistant) mice infected with both strains of T. cruzi began to spread rapidly at the onset of parasitaemia. Surprisingly, the amount of hydrogen peroxide released by peritoneal cells obtained from the more susceptible mouse strain (C3H) was significantly higher than in the other mouse strains. Also, only in the serum of C3H mice was tumour necrosis factor/cachectin detected. These results suggest that resistance against infections with myotropic strains of T. cruzi does not correlate with enhanced macrophage activation. It is also shown that the acquired macrophage activation is largely dependent on T‐lymphocytes bearing the phenotypic marker CD4 (helper/inducer), since all parameters of macrophage activation were significantly inhibited in athymic mice or in C3H mice treated in vivo with monoclonal antibody anti‐CD4+ T‐cells.
Vaccination trial against canine visceral leishmaniasis
Authors: DUNAN S. , FROMMEL D. , MONJOUR L. , OGUNKOLADE B. W. , CRUZ A. , QUILICI M. ,   THE PHOCEAN VETERINARY STUDY GROUP ON VISCERAL LEISHMANIASIS
Published: October 2007

Summary n a double‐blind study 393 seronegative dogs, residing in a holoende‐mic area for Leishmania donovani infantum infection, were randomly assigned to an immunization with a partly purified L.d. infantum‐derived preparation, or received adjuvant only. During the first year of the study period the rate of infection was significantly higher in the vaccinated group than in the control one (P < 005), but this difference disappeared during the second year (P = 0–44). Since a similar immunization protocol conferred resistance against experimental murine leishmaniasis, these results stress the differences that may exist between the natural hosts of Leishmania parasites and experimental animal substitutes.
Destruction of normal human eosinophils by Entamoeba histolytica
Authors: LOPEZ‐OSUNA MARTHA , KRETSCHMER ROBERTÓ R.
Published: October 2007

Summary We evaluated the in‐vitro interaction of normal human eosinophil leucocytes and a virulent strain of Entamoeba histolytica (HM1‐IMSS) in the presence of immune serum. At a 10:1 (eosinophil:amoeba) ratio a significant time‐dependent destruction of eosinophils was found from the first hour onward, and a similar, albeit weaker, cytopathic effect was found in the 200:1 ratio mixtures, with some delay in the microscopic evidence of such effect. Results were unaffected by serum factors, and amoebae emerged virtually unharmed throughout these experiments, again regardless of the presence of serum factors. These results indicate that, as with neutrophil leucocytes, virulent E. histolytica is capable of destroying normal human eosinophils in vitro.
Suppression of in–vitro lymphoproliferative responses in acute malaria patients can be partially reversed by indomethacin
Authors: RILEY E. M. , MACLENNAN C. , KWIATKOWSKI D. , GREENWOOD B. M.
Published: October 2007

Summary In–vitro lymphoproliferative responses to malaria antigens are suppressed in patients with acute Plasmodium falciparum infection. Studies with other parasitic diseases have suggested that monocyte/macrophage–derived prostaglandins may be responsible for immunosuppression. Since acute malaria infection is characteristically associated with fever it is likely that prostaglandin E production will also be enhanced in these patients. In this study, indomethacin, a cyclo–oxygenase inhibitor which blocks the synthesis of prostaglandins, was added to the culture medium during assays of lymphoproliferative responses to malaria antigens and other soluble proteins. Responses to several antigens were enhanced in the presence of indomethacin, indicating that prostaglandins may have a generalized immunosuppressive role in malaria–infected individuals. However, responses to malaria antigens were particularly enhanced by indomethacin, suggesting that malaria–specific T–cells are especially sensitive to the effects of prostaglandin, possibly due to prior activation in vivo by circulating malaria antigens.
Cross–reactivity of antibody against an epitope of the Plasmodium falciparum second merozoite surface antigen
Authors: SAUL A. , LORD R. , JONES G. , GEYSEN H. MARIO , GALE J. , MOLLARD R.
Published: October 2007

Summary Monoclonal antibodies directed against the 51 kD merozoite surface antigen of Plasmodium falciparum also bind to other antigens within the infected cell. The sizes of these cross–reacting antigens have been characterized. Immunofluorescence due to the reaction of one of the monoclonal antibodies with these cross–reacting antigens was localized in the intra–erythrocytic parasite and in granules in the infected red cell cytoplasm. This immunofluorescence could be distinguished from the merozoite surface antigen in parasite lines with a variant serotype of the merozoite surface antigen which fails to react with the monoclonal antibodies. It was found that the in–vitro growth inhibition caused by the presence of one of the monoclonal antibodies, 8G10/48, was dependent on the expression of the corresponding serotype of merozoite surface antigen, a finding consistent with the inhibitory effect of this antibody being primarily directed against the merozoite surface antigen and not the cross–reacting antigens. Analysis of the frequency at which epitopes occur suggests that such cross–reacting proteins will be commonly seen in malaria, without the need to postulate a selective advantage for such cross–reacting specificities.
Acute virulent infection with Plasmodium chabaudi does not impair the generation of a protective immune response
Authors: FALANGA PIERRE BARTHÉLÉMY , SILVA LUIZ PEREIRA DA
Published: October 2007

Summary We have investigated whether a protective immune response occurred in mice infected with a virulent cloned strain of Plasmodium chabaudi. Animals inoculated intravenously with 10′ parasitized erythrocytes (PE) showed an exponentially increasing parasitemia and died by day 6 of the infection, presenting a pronounced anaemia. Smaller inocula produced a longer pre–patent period but did not change the lethal course of infection, since mice injected with 100 parasites died on day 12. When anaemia was compensated for by red blood cell (RBC) transfusion, infected mice recovered and thereafter exhibited a strong immunity, comparable to that of mice immunized by a drug–controlled infection. The immune response was P. chabaudi specific, as the mice were fully susceptible to a challenge by P. yoelii. Three transfusions of 5 times 10′ RBC per mouse at 2–day intervals were necessary before all the animals were able to control the infection. Transfusion of a larger number of RBC resulted in a lower anaemia and a delay in reticulocytaemia but, paradoxically, the expression of the immune response was delayed. Three transfusions of 1–2 times 1010 RBC enabled three out of eight mice to survive the infection, while six transfusions enabled all the mice to survive. The data suggest that parasitized immature RBC could play an important role in triggering the protective immune response.