bluuebunny/crossref_metadata_2025 huggingface dataset:
Immunodepression and the course of infection of a chronic Trypanosoma brucei infection in mice
Authors: HUDSON K.M. , TERRY R.J.
Published: October 2007

Summary The relationships between course of infection, antigenic variation, and immunodepression of antibody responses to heterologous antigens have been investigated in mice chronically infected with Trypanosoma brucei. T. brucei Brunel University Trypanosomiasis (BUT) 64 produces a fluctuating parasitaemia lasting about 80 days and ending fatally. It is demonstrated that recurring peaks of parasitaemia are associated with the appearance of new variant antigenic types. At 21 and 31 days of infection, IgG responses to the heterologous antigen, sheep red blood cells (SRBC), are absent and IgM responses are less than 5% of normal. When a single dose of cyclophosphamide (300 mg/Kg) was injected into mice on day 31 of infection, the parasitaemia rose sharply in an uncontrolled fashion and the treated mice died in about 10 days. Cyclophosphamide, given in this way, is known to ablate antibody production completely but temporarily. It is therefore concluded that even though infected mice make extremely poor anti‐body responses to heterologous antigens, they are still capable of producing sufficient antibody to control peaks of parasitaemia associated with the emergence of new variant antigenic types. The significance of these findings is discussed in relation to current hypotheses of trypanosome‐associated immunodepression.
Trypanosoma cruzi: binding of parasite antigens to mammalian cell membranes
Authors: SANTOS R. RIBEIRO DOS , HUDSON L.
Published: October 2007

Summary Muscle and neuronal cell lines were infected with Trypanosoma cruzi and stained for the presence of parasite antigens by immunofluorescence. Up to 72 h post infection, fluorescence was limited to the intracellular amastigote stages. After the release of parasites, at about 96 h, fluorescence was also associated with the membranes of normal and infected cells. This finding was reproduced by passive sensitization of uninfected cells using amastigote antigens at protein concentrations as low as 10 μg ml‐1. Intriguingly, although both normal and transformed cells of muscle and nervous tissue origin adsorbed significant quantities of antigen, lymphocytes and erythrocytes failed to show any detectible uptake.
Complement (C3) levels and the effect of C3 depletion in infections of Trypanosoma brucei in mice
Authors: SHIRAZI MAHSHID FAGHIHI , HOLMAN MARY , HUDSON K.M. , KLAUS G.G.B. , TERRY R.J.
Published: October 2007

Summary Circulating C3 levels and parasitaemias have been measured in four groups of mice chronically infected with Trypanosoma brucei: group A (normal); group B (irradiated, reconstituted); Group C (T cell‐deprived); and group D (T cell‐deprived, C3‐depleted by treatment with cobra venom factor). In groups A‐C, C3 levels first rose two to three times normal, C3 thus behaving as an acute phase reactant. Three weeks after infection C3 returned to normal levels for the remainder of the infection. It is thus unlikely that the severe generalized immunodepression seen in mice infected with this trypanosome, is in any way dependent upon a reduction of circulating C3. The curves of parasitaemia in all four groups of mice were essentially similar, even though in group D mice, C3 levels were reduced to about 10% of normal for the first 3 weeks of infection. From this finding, it is argued that complement has no essential role in the mechanisms whereby mice control successive variant populations of T. brucei in the blood. Variant‐specific IgM antibodies, acting as trypagglutinins, are probably all that are required to control blood stream infections.
O‐antigenic specificity of the protective supernatant factor from Salmonella typhimuvium effective in S. typhimurium‐infected mice
Authors: PLANT JANET E. , GLYNN A.A. , VALTONEN M.V.
Published: October 2007

Summary A supernatant factor (SF) prepared from cultures of Salmonella typhi‐murium protected naturally susceptible inbred mice against challenge with S. typhimurium subcutaneously injected (s.c.i.). but not against Salmonella enteri‐tidis, suggesting that the relevant specificity involves lipopolysaccharide. Further experiments were performed with two transductant strains of S. typhimurium. Strain SH6701 has O‐antigen 4 from S. typhimurium and SH6703 has O‐antigen 9 from S. enteritidis. Immunization with SF from SH6701 protected 95% BALB/c mice challenged with 100 LD50 S. typhimurium s.c.i., whereas SH6703 immunization had no effect on survival or mean survival time. SH 6703 SF gave some protection against homologous challenge. Antibody titres and delayed‐type hypersensitivity reactions were also tested in immunized mice. The SF was, therefore, specific in that O‐antigen 4 was necessary to protect mice against S. typhimurium challenge. Since we have previously demonstrated protein to be necessary for protection by SF, the active factor may be in the form of a protein‐lipopolysaccharide complex.
Immunological regulation of experimental cutaneous leishmaniasis. 1. Immunogenetic aspects of susceptibility to Leishmania tvopica in mice
Authors: HOWARD J.G. , HALE CHRISTINE , CHAN‐LIEW W. LING
Published: October 2007

Summary Models of the different disease patterns of cutaneous leishmaniasis can be induced by the same dose of L. tropica promastigotes in various inbred strains of mice. The susceptibility of BALB/c is exceptional, essentially dosage independent (being demonstrable with as few as 20 parasites) and leads to huge progressive lesions with fatal visceral and cutaneous metastasis. Lesions also extend progressively but more slowly in DBA/1 and DBA/2 mice. Strains A, C57BL/6 and CBA are relatively resistant to even 2 × 107 promastigotes, with arrest of lesion growth within 3 weeks and subsequent gradual healing. Similar resistance of A.SW to 2 × 105 is overcome by a larger dose. The major inter‐strain differences are H‐2 independent, for C57BL/10 congenic mice possessing six different H‐2 antigen complexes all show early arrest of lesion growth leading to healing (H‐2s H‐2a, H‐2k) or mild residual disease (H‐2b H‐2d, H‐2q). Inter‐line differences within the latter group varied between experiments such that no clear rank order emerged. Inexorable disease progression was found in congenic BALB/B, BALB/c and BALB/K alike, although it was significantly slower in the latter line when infected with smaller doses. Genetic control of BALB/c susceptibility is thus predominantly in the non‐H‐2 background with only a minor H‐2 linked regulatory influence on the later stage. C57BL/6, BALB/c and their F1 hybrid characteristically display ‘healing’, ‘fatal progressive’ and ‘non‐healing’ lesions respectively over a wide dose range. ‘BALB/c‐like’ susceptibility segregates strictly in the F2 and backcross progeny according to a one predominant gene prediction. A comparison of the present data with those concerning genetic regulation of acute and chronic stages of systemic L. donovani infection in mice (Bradley, 1977, Blackwell, Freeman & Bradley 1980) reveals differing control for the outcome of cutaneous L. tropica infection, in which other important genetic influences must be involved.
Schistosoma mansoni: age‐dependent susceptibility to immune elimination of schistosomula artificially introduced into preinfected mice
Authors: BLUM K. , CIOLI D.
Published: October 2007

Mice chronically infected with Schistosoma mansoni exhibited a significant resistance to a second infection with the same parasite, as demonstrated by their challenge worm burdens measured by portal perfusion. A decreased worm recovery was also exhibited by chronically infected mice when the challenge was administered intravenously using 3‐h schistosomula obtained by the isolated skin technique or using 5‐, 6‐, 7‐ and 9‐day‐old schistosomula obtained from the lungs ofinfected donor mice. Variable results were obtained with 10‐ and II‐day‐old forms, while schistosomula which were 12days old or older, did not undergo significant rejection when introduced into the mesenteric veins of preinfected mice. Attempts to analyse these phenomena using the‘lung assay’were made complicated by the observation that the day of maximum recovery from the lungs was dependent upon the age of injected worms.
The response of mice immune to Schistosoma mansoni to a challenge infection which bypasses the skin: evidence for two mechanisms of immunity
Authors: MILLER K.L. , SMITHERS S. R. , SHER A.
Published: October 2007

Mice which had developed immunity to reinfection with Schistosoma mansoni following exposure to 20 cercariae and mice which had been immunized against S. mansoni by exposure to 400 highly irradiated (20 krad) cercariae, were tested for their ability to resist a percutaneous cercarial challenge and an intravenous challenge with 5‐day‐old lung‐stage schistosomula derived from the same cercariae. Although both types of immune mice showed a marked resistance to a cercarial challenge, only the infected mice showed a comparable immunity to an intravenous challenge with lung schistosomula. These results confirm earlier studies which suggest that the major attrition of a cercarial challenge in infected mice occurs at the post‐lung stage, whilst the attrition of a challenge infection in mice immunized with highly irradiated cercariae takes place in the skin. They provide further evidence for two separate mechanisms of immunity against S. mansoni in mice.
Serum‐mediated adherence of feline granulocytes to microfilariae of Brugia pahangi in vitro: variations with parasite maturation
Authors: JOHNSON P. , SUSWILLO R.R. , DENHAM D.A.
Published: October 2007

Feline eosinophils and neutrophils readily adhered in vitro to the sheaths of microfilariae of Brugia pahangi in the presence of suitable serum. Both cell types flattened along the surface of the parasite undergoing cytoplasmic changes which included degranulation. Adherence was dependent on properties of both the serum and the history of the microfilaria used. Two types of serum factor were found to mediate adherence. Heat labile factors were present in sera from infected and uninfected cats as well as in sera from other species. They were removed by preincubation of sera with zymosan suggesting that complement components were involved. This suggestion was supported by the demonstratior, of C3 on the surface of microfilariae participating in adherence reactions. A heat stable factor, present in the serum of less than 10% of infected cats, also mediated adherence. This factor was demonstrated to be IgG by immunoadsorption and immunofluorescence. The ability of the microfilariae to participate in the adherence reaction mediated by complement factor varied with maturation of the parasite. Microfilariae obtained directly from the uteri of adult worms, or produced in vitro, did not possess the ability to participate in adherence. Young blood microfilariae (i.e. taken from the blood of cats recently patent) were similar to the in vitro produced parasites; however, the majority of blood microfilariae from infections of greater than three weeks patency participated in this form of adherence. No difference between blood and uterinelin vitro microfilariae was seen in adherence reactions mediated by heat stable antibody.
Killing of newly excysted juveniles of Fasciola hepatica in sensitized rats
Authors: DAVIES CAROLINE , GOOSE J.
Published: October 2007

Newly excysted juvenile Fasciola hepatica were injected intraperitoneally into previously sensitized rats. They were recovered at various intervals post‐injection and examined by light and electron microscopy. The challenge flukes were rapidly coated with peritoneal cells which, in the early stages, were mainly eosinophils. The eosinophils adhered closely to the flukes and degranulated on to their surface releasing cytochemically detectable peroxidase. Vacuoles formed in the tegument of the flukes beneath the adherent eosinophils and these increased in size until they spanned the width of the tegument, thus destroying its continuity. From 4 h post‐injection some of the flukes had lost their teguments and were surrounded by phagocytic cells, particularly neutrophils; at this stage they were judged to be dead. During the first five minutes post‐injection degranulating mast cells were associated with the challenge flukes. Their role in eosinophil chemotaxis is discussed as are the possible mechanisms of eosinophil adherence and degranulation.

Using an anti‐C3 fluorescein conjugate, it was demonstrated that C3 was not bound to the surface of challenge flukes either in vitro or in vitro in immune serum.
Immune responses of rats to live Vibrio cholerae: secretion of antibodies in bile
Authors: JACKSON G. D. F. , COOPER G. N.
Published: October 2007

Agglutinating and vibriocidal antibodies appear in the bile of rats within a few days of intravenous or intraintestinal injection of live Vibrio cholerae. Whereas the presence of IgM and IgG antibodies are accounted for by passive exudation from serum, those of the IgA class are selectively (actively) transferred from serum to bile. Bile duct ligation causes a 10‐fold increase in serum IgA levels over a 48‐h period; a similar increase in agglutinating antibody titre occurs only in rats injected intraintestinally, thus providing further evidence for the predominance of IgA‐antibody formation when antigen is taken up from the intestinal lumen. Biliary antibodies do not appear to augment the antibody levels in mucus secretions that adhere to the small intestine surfaces. However, when the bile flow is interrupted by bile duct occlusion or cannulation, the antibody levels in these secretions increase in parenterally‐immunized animals. It is unlikely, therefore, that bile duct ligation will provide a satisfactory approach to determining the protective function of biliary V. cholerae antibody.
Immunization of ferrets against Diroflaria immitis by means of chemically abbreviated infections
Authors: BLAIR LYNDIA SLAYTON , CAMPBELL W. C.
Published: October 2007

Ferrets were exposed to two successive inoculations with 30 third‐stage larvae of the canine heartworm Dirofilaria immitis, the inoculations being approximately 5 months apart. Each infection was terminated by ivermectin therapy approximately 2 months after inoculation. The ferrets were challenged with 30 larvae 3 weeks after the termination of the second infection, and were necropsied approximately 6 months after challenge. Of the four ferrets that survived this protracted experimentation, two were entirely free of heartworm while the other two had only a single female worm each. In contrast, 14 control ferrets that had not been immunized (four of which had been given ivermectin doses) were all infected at necropsy, yielding a mean of 6.6 worms per ferret.
Stimulation of immunity to Nematospiroides dubius in mice using larvae attenuated by cobalt 60 irradiation
Authors: HAGAN P. , BEHNKE J.M. , A. PARISH HEATHER
Published: October 2007

Infective larvae of Nematospiroides dubius attenuated by cobalt 60 irradiation are extremely effective at stimulating immunity. Previously, such levels of protection could only be obtained with multiple immunizations of normal larvae. The critical factor underlying this protective response appears to be the dose of irradiation given to the immunizing infection. Various doses of irradiation have been tested and the most effective of these range between 10 and 30 krad. The experiments show that provided this level of irradiation is used, the number of immunizing infections is relatively unimportant. Such use of irradiated larvae will be of value in attempting to analyse the immune mechanisms which operate against N. dubius. The possible mechanisms of immunity to N. dubius are discussed.
Immunity to Strongyloides ratti in rats. 1. Adoptive transfer with mesenteric lymph node cells
Authors: MOQBEL R. , WAKELIN D.
Published: October 2007

Adoptive transfer of immunity against the enteral phase of Strongyloides ratti was monitored using four parameters; namely, number of worms recovered, position occupied in the host's small intestine, worm length and fecundity. When immune mesenteric lymph node cells (IMLNC) were transferred from donors infected for 20, 26 or 32 days into recipients infected for 3 days, a marked acceleration of worm expulsion was evident by day 16 post‐infection (p.i.). IMLNC from day‐16 p.i. donors did not transfer expulsion. In an experiment in which recipients were given 2 × 108 or 1 × 108 IMLNC from donors infected for 26 days, accelerated worm expulsion occurred only with the higher inoculum, although manifestations of direct worm immunity, i.e. altered position and reduced length and fecundity, were evident in both cases. Transfer of IMLNC appeared to have no effect upon worm establishment; when cells were transferred on the day of infection a period of 16 days was necessary to effect both direct anti‐worm immunity and expulsion, although the former was evident on day 14 p.i. However, when IMLNC were transferred to rats already infected for 6 days, a very significant reduction of their worm burden was apparent 10 days after IMLNC transfer.
The nature of immunity against Trypanosoma crtczi in mice recovered from acute infection
Authors: SCOTT M.T.
Published: October 2007

Protective immunity against a lethal, Y strain, T. cruzi infection could be transferred to normal mice by either serum or spleen cells from mice which had recovered from the acute phase of infection. The ability of spleen cells to transfer immunity was abolished by B lymphocyte removal (anti‐Ig column fractiona‐tion), but was relatively insensitive to T lymphocyte depletion (anti‐Thy 1.2 plus complement) or macrophage removal (Sephadex G‐10 fractionation). Immune spleen cells gave an anamnestic antibody response when injected together with T. cruzi antigen into lethally irradiated recipients and these antibodies conferred protection in a passive transfer system. T cell depletion reduced, but did not abolish, this antibody response. These data imply that the protective immunity of T. cruzi‐convalescent mice is predominantly B cell‐mediated with T cell involvement being restricted to a helper role.
Suppressor T cells in the specific control of the carrier response to schistosomula in mice infected with Schistosoma mansoni
Authors: RAMALHO‐PINTO F.J. , SMITHERS S.R.
Published: October 2007

The carrier effect, using TNP‐labelled schistosomula was used to measure the helper T‐cell activity against the schistosomula surface in CBA mice exposed to 30 cercariae of Schistosoma mansoni. After infection the helper T‐cell activity reached a peak in 8–10 days, but by 6 weeks it had declined to background levels. Five × 107 spleen cells from chronically (12‐week) infected mice when injected into 9‐day infected mice caused a specific suppression of the helper T‐cell response to schistosomula. Subsequent fractionation of the spleen cell population using a nylon wool column and specific depletion of T cells from the spleen cell population with anti‐Thy 1·2 antisera and complement, showed that the suppressive activity was due to T cells. We conclude that during infection of mice with S. mansoni a population of suppressor T cells is generated which partially regulates antibody production against schistosome surface antigens.
Characterization of surface antigens of Trichinella spiralis infective larvae
Authors: Parkhouse R.M.E. , Philipp M. , Bridget  , Ogilvie M.
Published: October 2007

Infective larvae of Trichinella spiralis were surface‐labelled with radioactive iodine, and the products were characterized biochemically and immunochemically. The labelled material was restricted to two basic subunits: a lentil lectin‐adherent glycoprotein (GP), mol. wt 47K, and a lentil lectin‐non‐adherent protein fraction (P), mol. wt 55K. Both of these form homologous dimers through as yet unspecified covalent bonds to yield GP90 and P105. The GP is further polymerized into higher molecular weight forms by disulphide bond‐dependent associations, suggesting a highly cross‐linked arrangement in the cuticle. To what extent this structure contributes to the overall organization of the cuticle remains to be established. The two labelled surface molecules are immunogenic in the infected host, and do not react with a panel of sera taken from animals chronically infected with other nematode species. The approach therefore offers immediate possibilities for immunodiagnosis in nematode infections, and for a comparative immunochemical study of the surface cuticle of different stages of the same and different nematode species and for studies of the function of the nematode cuticle.
Immune recognition of Echinococcus granulosus. 1. Parasite‐activated, primary transformation by normal murine lymph node cells
Authors: DIXON J. B. , JENKINS P. , ALLAN D.
Published: October 2007

Summary Culture of murine lymph node cells together with living protoscolices of Echinoccus granulosus is described. The presence of the parasite induced potent blastic transformation in lymphocytes of unimmunized mice as indicated by tritiated thymidine incorporation. The response was markedly reduced by killing the parasite immediately prior to culture. No blastogenic activity was detectable in supernatants from living parasites cultured alone. Protoscolices from artificially infected syngeneic mice were effective stimuli, as were protoscolices from naturally infected horse and sheep. Stimulation was not detectably reduced by maintenance of the parasite in vitro for 72 h at 37°C or for 46 days at 4°C prior to culture. It is concluded that unprimed lymphocytes are stimulated to transform by surface contact with a stimulator synthesized, but not secreted, by the parasite. The biological significance of the reaction and its possible contribution to immunosuppression are discussed.
Immunological and histopathological reactions of the rat against the tapeworm Hymenolepis diminuta and the effects of anti‐thymocyte serum
Authors: HINDSBO O. , ANDREASSEN J. , RUITENBERG J.
Published: October 2007

Summary Anti‐thymocyte‐serum (ATS) treated Wistar rats infected with 100 cysticercoids of the rat intestinal cestode Hymenolepis diminuta showed a delayed destrobilation and expulsion of the worms compared with saline‐treated infected rats. This result strengthens previous evidence of an immunological nature of the destrobilation and expulsion in lumen‐dwelling cestodes—even in their most susceptible hosts. The migration of the worms in the small intestine during the first 20 days of a primary 100‐worm infection is described and the anterior migration of the destrobilated worms to the first 10% of the pylorus is emphasized and compared with similar migrations of the nematode Nippostrongylus brasiliensis in the rat. No serum antibodies were detected using passive cutaneous anaphylaxis and the indirect immunofluorescence test, although the thymus‐independent areas of the mesenteric lymph nodes showed an increase in pyroninophilic cells. In the small intestine, no response to the tapeworm infection could be detected in pyroninophilic cells and globule leucocytes, but mast cell and eosinophilic cell numbers were increased in the saline‐treated infected rats. Although the host responses to H. diminuta are shown to be thymus‐dependent, the possibility of thymus‐independent activity in the host reactions cannot be ruled out.
Killing of the malarial parasite Plasmodium yoelii in vitro by cells of myeloid origin
Authors: TAVERNE JANICE , DOCKRELL HAZEL M. , PLAYFAIR J. H. L.
Published: October 2007

Summary Cytotoxic effects of mouse cells on Plasmodium yoelii were sought directly by incubating parasitized red cells with cells of various kinds for 16 h and then determining the percentage parasite survival in vivo, in terms of infectivity for the mouse. Cell populations rich in lymphocytes, e. g. lymph node and spleen, were less active than peritoneal cells and blood. Parasite killing by peritoneal cells was associated with macrophages: treatment with anti‐macrophage serum (AMS) or depletion by adherence or centrifugation on Ficoll decreased activity. Polymorphonuclear leucocytes (PMN) in induced exudates may have contributed to killing, although not as actively cell for cell, and an effect of eosinophils in worm‐induced exudates was not excluded. White blood cells were most active of all and fractionation on Ficoll confirmed that lymphocytes were relatively ineffective. The effector cell was phagocytic but it was insensitive to AMS. Tests on populations with high or low proportions of PMN showed that parasite killing was independent of PMN number. It is concluded that the effector cell belongs to the monocyte‐macrophage series and has acquired the ability to kill the parasite before becoming fully differentiated into a macrophage.
BCG‐induced inhibition and destruction of Taenia taeniaeformis in mice
Authors: THOMPSON R. C. A. , PENHALE W. J. , WHITE T. R. , PASS D. A.
Published: October 2007

Summary Pretreatment of mice with BCG induced a high level of protection against infection with Taenia taeniaeformis. Protection was manifested both during and after establishment by the parasite suggesting that two separate mechanisms were stimulated by BCG. The first inhibits initial establishment by the parasite and may be antibody mediated. The second is responsible for the destruction of developing strobilocerci in the liver and may require the involvement of cellular defence mechanisms.
Peanut agglutinin affinity chromatography of Trypanosoma cruzi glycoproteins
Authors: MARCIPAR A. J. , LENTWOJT E. , SEGARD E. , AFCHAIN D. , FRUIT J. , CAPRON A.
Published: October 2007

Summary Glycoproteins from Trypanosoma cruzi epimastigotes have been extracted by diiodosalycilic acid and lithium salts, and phenol‐water biphasic partition. Peanut agglutinin has been used in a one step preparative method for fractionating the total extract in order to separate the so‐called galactose‐terminal glycoproteins. The different fractions have been studied by SDS electrophoresis, ultracentrifugation and immunoelectrophoresis techniques. The experimental immunogenicity, antigenicity and specificity of the PNA affinity fractions has been evaluated.
The protective role of acquired host antigens during schistosome maturation
Authors: MCLAREN DIANE J. , TERRY R. J.
Published: October 2007

Summary Schistosomes grown in mice were tested at different stages of development for susceptibility to an in vitro cytotoxic effector mechanism involving eosinophils and an antibody directed against mouse determinants. Despite the fact that 5‐day lung worms and 6‐week adult worms both bound the antibody to their surfaces, eosinophils attached preferentially to the adults and killed them. Complement had an enhancing effect in this system. Those eosinophils which did adhere to the lung worms degranulated onto the tegument but were unable to mediate damage or killing, even when complement was activated at the parasite surface. The resistance shown by the lung worms was shared by 2‐week worms and small 3‐week worms. Larger 3‐week worms and older stages were, however, susceptible to cell‐mediated cytotoxicity in this system. We suggest that the host antigen disguise constitutes the major protective mechanism utilized by older schistosomes to evade immunity, but that the younger stages have an additional and equally effective mechanism of resistance.
The in‐vitro interaction between several components of the canine immune system and infective larvae of Ancylostoma caninum
Authors: KLAVER‐WESSELING J. C. M. , VETTER J. C. M. , SCHOEMAN E. N.
Published: October 2007

In this paper, in‐vitro experiments are reported which indicate that in dogs infected with the hookworm Ancylostoma caninum, there exists a cooperation between specific IgG antibodies and fixed complement components (C3). This relation is important in the adherence of peripheral blood leucocytes to the surface of the larvae. Fixation of complement occurs via the alternative pathway.
The protein‐lipopolysaccharide complex extracted with trichloracetic acid from Salmonella typhimurium effective in protection of mice against S. typhimurium infection
Authors: PLANT JANET E. , WILSON B. M. , GLYNN A. A.
Published: October 2007

A protein‐lipopolysaccharide complex has previously been postulated as necessary to protect susceptible mice against Salmonella typhimurium infection. Lipopolysaccharide attached to non‐specific proteins, bovine serum albumin or methylated BSA, gave a specific delayed‐type hypersensitivity (DTH) reaction when injected into the footpad of mice sensitized with sublethal doses of S. typhimurium. However, immunization of BALB/c mice with the complex gave no survivors after challenge with 100 LD50S. typhimurium. Trichloracetic acid extraction of bacterial cultures produced lipopolysaccharide with attached protein. This method gave simple and convenient production of an active factor, demonstrating few major protein bands after electrophoresis. The complex elicited specific DTH reactions in sensitized mice and protected 37% of BALB/c mice against 100 LD50S. typhimurium. Combinations of protein:lipopolysaccharide were used in DTH experiments to determine the relative importance of the components. A minimum requirement for both was demonstrated, although the ratio was not critical. Use of O‐antigenic mutant strains of Salmonella indicated a role for protein in the specificity of activity of the complex.
Suppression of mitogen‐induced lymphocyte transformation by plasma from patients with hepatosplenic Schistosomiasis mansoni: role of immune complexes*
Authors: KAMAL K. A. , HIGASHI G. I.
Published: October 2007

Plasma from chronic or advanced hepatosplenic schistosomiasis (mansoni) patients (PCS) suppressed mitogen‐induced responses of normal human peripheral blood mononuclear cells. 1 × 105 Ficoll‐Hypaque isolated lymphocytes were cultured in 100 μ1 RPMI 1640 media with 100 μ1 plasma preparation and stimulated with phytohemagglutinin P (PHA), concanavalin A (Con A), pokeweed mitogen (PWM) and Staphylococcus aureus phage lysate (SPL). Compared to normal human plasma, dose‐response experiments with 10–50% PCS uniformly inhibited the 72‐h PHA, Con A and PWM responses with maximal suppression at 50% plasma concentration. At this concentration, the range of suppression was 42–60%. The inhibitory activity was unaffected by 56°C, 30 min pretreatment of PCS. However, pre‐culture of cells with PHA for 24 h prior to addition of 50% PCS abrogated the suppressor activity. Furthermore, 6‐day cultures with PWM and SPL were not suppressed by 50% PCS. Plasma suppressor activity was nearly eliminated by pre‐treatment of PCS with 4% (w/v) polyethylene glycol (PEG) in all cases. In the putative immune complexes in the PEG precipitates, C1q, C3, C4, IgG, IgM and IgA were identified in nearly all PCS samples. Schistosomal antigen was found in only two of 23 PCS samples tested and significant anti‐schistosomal IgG antibodies were found in all PEG precipitates. The data suggest immune complexes (non‐specific and specific) act to suppress 72‐h mitogenic responses.
Apparent irrelevance of NK cells to resolution of infections with Babesia microti and Plasmodium vinckei petteri in mice
Authors: WOOD P. R. , CLARK I. A.
Published: October 2007

Increased natural killer (NK) cell activity was found in the spleen and peritoneal cavity of mice infected with Babesia microti or Plasmodium vinckei petteri. This increased activity appeared not to be associated with the effectiveness of the host response against these parasites, since it reached its maximum when the parasitaemia was still low, and had decreased by the time the parasites reached peak densities. In addition mice pretreated with 89Strontium or 17β‐oestradiol experienced the same pattern of infection as did control mice, yet the infections induced much lower levels of NK activity in the pretreated mice. The course of infection with B. microti was also unaltered in beige mice, which are genetically deficient in NK cells. Thus we consider it unlikely that NK cells are of primary importance in non‐specific immunity to these haemoprotozoan infections.
Interleukin 2 secretion by sensitized cells from mice infected with Nematospiroides dubius: kinetics and specificity of the response
Authors: PROWSE S. J.
Published: October 2007

The lymphokine Interleukin 2 (IL2) is secreted by T lymphocytes from mice infected by the murine parasitic nematode Nematospiroides dubius upon in vitro re‐stimulation by specific parasite antigens. This study showed that the lymphocytes secreting IL2 were located in the lymphoid tissues draining the site of infection as well as in the spleen and peritoneal cavity of infected mice. There were marked fluctuations in the numbers of IL2 secreting cells in the posterior gastric lymph nodes and the peritoneal cavity at various times following single or multiple infections. However, there was no correlation between the appearance of IL2 secreting cells in infected mice and the development of resistance to re‐infection by third stage larvae (L3). The specificity of the IL2 response for N. dubius antigens was demonstrated by the finding that antigen preparations from other helminths did not stimulate a response. It was also found that living but not killed N. dubius L3 could stimulate IL2 secretion, emphasizing the importance of living L3 in the induction of resistance to re‐infection.
Expression of strain‐specific surface antigens on Plasmodium falciparum‐infected erythrocytes
Authors: HOMMEL M. , DAVID P. H. , OLIGINO LYNETTE D. , DAVID J. R.
Published: October 2007

Antigenic determinants present on the surface of squirrel monkey erythrocytes infected with late developmental stages of P. falciparum were recognized through their ability to bind antibodies present in the serum of immune monkeys. Two different assays were used to demonstrate the presence of these antigenic determinants on the cell surface: the fluorescent labelling of intact cells in suspensions and the binding to protein A‐Sepharose. Such determinants appear to be strain‐specific and have, for a given strain, a variable expression according to whether the parasites are taken from intact or splenectomized animals or whether they have been grown in vitro.
Effects of trichinellosis on levels of eosinophils, eosinophil major basic protein, creatine kinase and basophils in the guinea pig
Authors: LINDOR L. J. , WASSOM D. L. , GLEICH G. J.
Published: October 2007

Summary The effects of multiple infections with Trichinella spiralis on the levels of eosinophil major basic protein (MBP), creatine kinase (CK), and leucocytes were studied in the guinea pig. Plasma MBP levels increased after each of four successive infections with T. spiralis. The times of peak elevations in MBP levels and eosinophilia correlated significantly, and both peaks occurred earlier with increased infection dose. CK levels were elevated most dramatically in the primary infection. A direct correlation between peak CK values and larval dose was observed, and the peak occurred earlier with larger larval doses. A dose‐dependent basophilia was observed in the primary infection and, like the eosinophil response, basophilia occurred earlier and was markedly enhanced after the second infection. The elevations in MBP levels and eosinophil counts persisted into the third and fourth infections; the basophil response persisted only through the third infection.
Sj23, the target antigen in Schistosoma japonicum adult worms of an immunodiagnostic hybridoma antibody
Authors: CRUISE KATHY M. , MITCHELL G. F. , GARCIA E. G. , TIU W. U. , HOCKING ROBYN E. , ANDE R.F.
Published: October 2007

Summary An IgG2a mouse hybridoma‐derived antibody (designated I.134) has been identified which binds to Schistosoma japonicum adult worms and which has immunodiagnostic potential (for detection of antibody) in schistosomiasis japonica in the Philippines. The target epitope of this hybridoma antibody is contained in a 23 000 molecular weight protein of adult worms as analysed by one‐dimensional sodium dodecyl sulphate‐polyacrylamide gel electrophoresis of immunoprecipitates and a gel overlay technique. This adult worm antigen has been labelled biosynthetically using35 S‐methionine as well as exogenously using lactoperoxidase‐catalysed radioiodination and the Bolton and Hunter reagent with intact worms. As anticipated, the low molecular weight protein antigen (designated Sj23) appears to be one of several major immunogenic proteins of worms which induce antibodies in infected Philippine patients.
Plasmodium falciparum parasites induce interferon production in human peripheral blood ‘null’ cells in vitro
Authors: RÖNNBLOM L. , OJO‐AMAIZE E. A. , WIGZELL H. , ALM G. V.
Published: October 2007

Summary Human peripheral blood mononuclear cells were found to produce interferon (IFN) when stimulated by free P. falciparum parasites in vitro. On the other hand parasite‐infected, intact erythrocytes were unable to induce IFN synthesis. When the IFN was characterized according to sensitivity to anti‐IFN‐α antibodies and pH 2 treatment it was found to consist of IFN‐α. Cell fractionation procedures and analysis of each cell fraction with regard to natural killer (NK) cell activity and IFN‐producing capacity revealed that both activities were confined to the same cell fraction. The possible relevance of the IFN‐NK cell system in malaria is discussed.
Immune depression in bovine trypanosomiasis: effects of acute and chronic Trypanosoma congolense and chronic Trypanosoma vivax infections on antibody response to Brucella abortus vaccine
Authors: RURANGIRWA F.R. , MUSOKE A.J. , NANTULYA V.M. , TABEL H.
Published: October 2007

Summary Cattle were vaccinated with Brucella abortus (S19) vaccine during acute (25 days) and chronic (25 weeks) Trypanosoma congolense and chronic Trypanosoma vivax (25 weeks) infections in order to determine the effect of such infections on the antibody response to the vaccine. It was found that the specific antibody responses of IgG1 and IgG2 sub‐classes were profoundly depressed (80%) in both the acute and chronic infections with T. congolense. Whereas IgM antibody response was also profoundly depressed (90%) in cattle with the acute infection, it was only 50% depressed in those with chronic infection. There was no depression of IgG1, IgG2, or IgM in cattle infected with T. vivax. These animals, however, had no detectable parasitaemia at the time of vaccination and thereafter. These results suggest that during acute infection with T. congolense depressive mechanisms could be acting on the afferent arm of the immune response, namely, antigen recognition and/or processing.
Specific antibody responses to the variable surface glycoproteins of Trypanosoma congolense in infected cattle
Authors: MASAKE RACHAELA. , MUSOKE A.J. , NANTULYA VINAND M.
Published: October 2007

Summary Sera from cattle infected with three Trypanosoma congolense clones (ILNat 2.1, ILNat 3.1 and ILRAD 588) derived from different stocks were analysed for the presence of specific antibodies against the surface glycoproteins (VSGs) of the infecting trypanosomes using the solid and liquid‐phase radioimmunoassays and the neutralization of infectivity test. High levels of IgM, IgGi and IgG2 antibodies against the VSGs of the infecting variable antigen types (VATs) as well as other VATs that arose during the course of infection were detected. In addition, 11 out of 12 infected animals showed recurrent peaks of antibody activity against the infecting trypanosomes. The recurrent peaks of antibody activity against the VSGs of the infecting organisms would suggest either a reappearance of trypanosomes of the infecting types or emergence of organisms that bear similar surface determinants. In contrast to the studies on murine trypanosomiasis, there was little or no antibody activity against 2, 4, 6‐trinitrophenylated bovine serum albumin (TNP‐BSA) in sera from these cattle.
Nematospiroides dubius in the mouse: evidence that adult worms depress the expression of homologous immunity
Authors: BEHNKE J.M. , HANNAH J. , PRITCHARD D.I.
Published: October 2007

Summary Mice immunized by a single infection with irradiated (25 krad) larvae of N. dubius were very resistant to subsequent challenge. However, when normal larvae were administered together with irradiated larvae at immunization, the acquired immunity expressed against a challenge infection was markedly depressed. It was found that as few as 50 normal N. dubius larvae interfered with the immunity that would have otherwise been elicited by the concurrently administered irradiated larvae, but this depressed response was totally alleviated when the normal worms were removed after completing their development in the intestinal mucosa and before they reached adulthood. Adult TV. dubius were transplanted directly into the intestines of mice either 7 days before or after immunization by irradiated larvae; it was shown that the recipient mice were less resistant to challenge than mice which had been sham operated. Transplanted adult worms themselves stimulated very little resistance to challenge in recipient mice. These results established that adult parasites are capable of depressing the expression of homologous immunity in the mouse. The possible mechanisms by which JV. dubius might modulate the host's immunological activity at the intestinal level are discussed and it is proposed that this mechanism is of benefit to the parasite in preventing the host from eliminating the worms during a chronic primary function.
Fasciola hepatica: development of monoclonal antibodies and their use to characterize a glycocalyx antigen in migrating flukes
Authors: HANNA R.E.B. , TRUDGETT A.G.
Published: October 2007

Summary Using mice harbouring early Fasciola hepatica infections, six monoclonal antibodies were prepared against a tegumental antigen present in T1 granules and glycocalyx of flukes. Blocking tests indicated that all monoclonals bound the same T1 epitope (or epitopes in close proximity on the antigen molecule), but this was not the determinant recognized by sheep and cattle. Localization of antibody binding at light and electron microscope levels showed that T1‐type antigen also occurred in metacercarial tegument and in glycocalyx of gut cells and excretory ducts in juvenile and adult flukes. This indicates that the natural host‐antibody response to F. hepatica may be to one antigen early in the infection. Protein A‐gold labelling of monoclonal treated fluke sections revealed that the epitope was probably a polypeptide, unmodified by glycosylation in Golgi bodies. When isolated by immunoadsorption and separated electrophoreti‐cally under reducing conditions T1‐type antigen was found to consist of a polypeptide mol. wt. 50000, possibly linked to smaller entities mol. wt. 25–40 000. Tissue‐specific variations in the antigen molecule might be conferred by linkage of different polypeptides or carbohydrate side‐chains to an antigenic core polypeptide. A component of T1‐type antigen was found to have mol. wt. of 25000, possibly resembling a polypeptide of mol. wt. 24000 from Schistosoma mansoni tegument.
Antibodies to coccidia: detection by the enzyme‐linked immunosorbent assay (ELISA)
Authors: ROSE M.ELAINE , MOCKET A.P.A.
Published: October 2007

Summary The ELISA test was used for the detection of antibodies to coccidia in the serum and/or egg yolk of chickens infected with Eimeria acervulina, E. maxima or E. tenella and in the serum of rats infected with E. nieschulzi. Antigens prepared from different developmental stages of the parasite were tested and the cross‐reaction between different species of Eimeria were examined. The variability in cross‐reactivity of different species and the advantages and possible applications of the test are discussed.
Alternative pathway activation of complement by African trypanosomes lacking a glycoprotein coat
Authors: FERRANTE A. , ALLISON A.C.
Published: October 2007

Summary An in vitro culture Trypanosoma congolense cell line was established using the mammalian cell feeder layer system. One of the principle characteristics of this parasite was its ability to multiply in culture at 35°C, as an uncoated trypanosome (lacking a glycoprotein surface coat) unlike the original blood stream form from which it was derived. This trypanosome was lysed when incubated in normal human serum in contrast to the parasite which possessed a surface coat. The lytic reaction was inhibited by EDTA but not EGTA and occurred in C2‐deficient serum, demonstrating the involvement of the alternative pathway of complement activation. Similar results were obtained with procyclic forms of T. congolense and T. brucei brucei which also lacked surface coats. The results suggest that the glycoprotein surface coat protects the parasite by masking sites on the plasma membrane which are capable of promoting alternative pathway activation.
Studies on the development of anti‐schistosomular surface antibodies by mice exposed to irradiated cercariae, adults and/or eggs of 5. mansoni
Authors: BICKLE Q.D. , FORD M.J. , ANDREWS B.J.
Published: October 2007

Summary Levels of antibody a binding to the schistosomulum surface and b mediating in vitro eosinophil‐dependent cytotoxicity of schistosomula were studied and compared to the in vivo levels of resistance to cercarial challenge in mice infected with irradiated cercariae, unirradiated cercariae of single or mixed sex, or injected with eggs. Antibody‐binding was assessed by counting the number of IgG‐Fc‐receptor bearing cells (P388D1 cells) adhering to mechanically‐transformed schistosomula. Significant levels of adherence occurred with sera taken from 1–2 weeks following exposure to irradiated cercariae, the level increasing gradually thereafter and being enhanced by repeated exposure. Sera from the bisexual infection showed a dramatic increase in binding activity between weeks 5–8, and with the single sex infections there was a steady rise up to week 10 followed by a sharp rise between weeks 10–12. Weekly injections of eggs produced a steady rise in serum binding activity. Sera taken just before challenge were also tested for their ability to mediate killing of schistosomula by eosinophil‐enriched preparations of heterologous rat peritoneal exudate cells in vitro. Significant levels of killing occurred with all sera, but the greatest lethal activity was found in sera from the egg‐injected, chronically‐infected and 200 male cercariae‐infected groups. This ranking did not correlate with in vivo resistance against challenge as assessed by worm recovery, the egg‐injected and single sex‐infected groups failing to manifest significant resistance.
Infection of inbred and nude (athymic) rats with Brugia spp.
Authors: CRUICKSHANK J. K. , PRICE K. M. , MACKENZIE C. D. , SPRY C. J. F. , DENHAM D. A.
Published: October 2007

Summary Infective larvae of Brugia pahangi were injected subcutaneously into inbred PVG (‐RIT) rats, and ‘nude’ (PVG ‐rnu/rnu) (athymic) rats. Adult worms or circulating microfilariae were recovered from 20/34 (59%) of PVG ‐RTIC rats and from 30/30 (100%) of ‘nude’ rats. Fertile worms were regularly found in the lumbar lymphatics and hearts of both strains of rat. Blood eosinophilia first developed in PVG ‐RTIc rats about 17 days, and in all such animals by 6 weeks. High circulating eosinophil counts persisted only in patent animals, proving a useful hallmark for the presence of microfilariae. Nude rats despite patency, developed eosinophilia only latterly and then to a lesser extent. Specific anti‐2?. pahangi IgG antibody was first detected at 7 days in all infected PVG ‐RTT rats, with levels rising until 8 weeks and remaining high only in microfilaraemic animals; total IgE showed a similar response. Specific IgE rose in all the eight patent rats inconsistently and only to low levels in eight non‐patent infected rats. IgG and IgE were undetectable in nude rats. Other strains of inbred rats of different RTI haplotype were also successfully infected with B. pahangi and the human parasite B. malayi, a total of 10/23 (43%) and 5/15 (33%) becoming patent respectively. In the small numbers tested no major influence of RTI haplotype was detected. Infection by the intraperitoneal route did not result in the development of microfilariae. The difference in patency rates between ‘nude’ and normal PVG rats supports the contention that the development of filarial infections is T lymphocyte dependent. Inbred and ‘nude’ rats provide a valuable model of human filariasis, in which many features of filarial immunopathology can be studied.