bluuebunny/crossref_metadata_2025 huggingface dataset:
Alterations in blood eosinophil morphology, binding capacity for complexed IgG and kinetics in patients with tropical (filarial) eosinophilia
Authors: SPRY C. J. F.
Published: October 2007

As the significance of the eosinophilia which is found in some patients with chronic filarial infections is unknown, blood eosinophils were studied in seven patients with tropical (filarial) eosinophilia who had blood eosinophil counts between 5·2 and 56·6 × 109/1. In six of these patients over 20% of the eosinophils were vacuolated, and degranulated eosinophils were found in the three patients with the most severe illness. In four patients serum eosinophil cationic protein levels were raised, and serial studies in two showed that they returned to normal after treatment with diethylcarbamazine. In addition, an increased proportion of eosinophils in these patients were able to bind to complexed IgG suggesting that they were responding to stimuli in the blood, and in one patient the blood eosinophil half‐time clearance was prolonged. Labelled cells were cleared into the spleen, liver and bone marrow. These findings support the hypothesis that in patients with tropical (filarial) eosinophilia, blood eosinophils are induced to release their granule constituents into the circulation. It is suggested that these secretion products may interact with microfilariae, and may give rise to some of the clinical features of chronic filarial infections.
Proteolytic cleavage of IgG bound to the Fc receptor of Schistosoma mansoni schistosomula
Authors: AURIAULT C. , OUAISSI M.A. , TORPIER G. , EISEN H. , CAPRON A.
Published: October 2007

After the binding of IgG to the surface Fc receptor of Schistosoma mansoni schistosomula, the Fab portions of IgG are cleaved and small peptides are liberated in the culture medium. At least two types of proteinase activities have been demonstrated in the secretory products of schistosomula. One is an endoprotease with trypsin‐like activity, with an optimum pH of 7 and an optimum temperature of 45°C. The other is a metalloaminopeptidase with an optimum pH of 7 and temperature of 37°C.
A study of immunoregulation of BALB/c mice by Echinococcus granulosus equinus during prolonged infection
Authors: ALLAN D. , JENKINS P. , CONNOR R. J. , DIXON J. B.
Published: October 2007

Two models of intraperitoneal infection with E. granulosus equinus by protoscolices and by cyst passage in BALB/c mice were used to provide mesenteric lymph node cells for adoptive cell transfer into syngeneic recipient normal responder mice. The cell transfer inocula were shown to have depleted Thy‐1 cells, but to be highly suppressive to the normal sheep erythrocyte response of the recipients. The nature of the depletion and non‐specific suppression, and the infectious nature of the latter, are discussed in relation to other examples of mitogenic stimulation resulting in non‐specific T cell suppressor activity. The functions of Ly‐2,3+ cells, not only as suppressor, but as alloreactive cytotoxic cells, are discussed as a possible, autoimmune explanation for the longevity of the parasite within the mouse model, in contradistinction to the predictable early rejection of analogous xenografts.
Severe strongyloidiasis associated with hypogammaglobulinaemia
Authors: OLIVEIRA R.BRANDT DE , VOLTARELLI J. C. , MENEGHELLI U. G.
Published: October 2007

The association of severe strongyloidiasis and hypogammaglobulinaemia in one patient is described. Severe strongyloidiasis was observed twice (March 1971 and June 1974), and the Strongyloides stercoralis infestation probably lasted for at least 58 months (from March 1971 to December 1975), in spite of successive thiabendazole courses of treatment. Immunological studies performed disclosed severe, steady hypogammaglobulinaemia but no abnormality in cell‐mediated immunity. The respiratory infections also seen during the follow‐up were ascribable more to humoral immunity impairment than to cell‐mediated immunity impairment. This is the first report of the association of hypogammaglobulinaemia and severe strongyloidiasis, and it suggests that humoral immunity plays a relevant role in the human defences against S. stercoralis infestation.
The heterolgous protection of rats against a challenge with Fasciola hepatica by prior infection with the nematode Nippostrongylus brasiliensis
Authors: DOY T.G. , HUGHES D.L. , HARNESS E.
Published: October 2007

Previous infection of rats with Nippostrongylus brasiliensis was shown to result in protection against an oral challenge with Fusciola hepatica metacercariae but not against an intraperitoneal challenge with newly excysted juvenile (NEJ) flukes. The timing of the challenge was important and a double infection with the nematode gave more consistent results than a single. Resistance appeared to be associated with a prior induction of intestinal eosinophilia. Sera from these resistant rats, however, failed to induce eosinophil adherence to NEJ flukes in vitro.
An investigation of the antigenic structure of Toxoplasma gondii
Authors: HUGHES H.P.A. , BALFOUR A.H.
Published: October 2007

Mechanical fragmentation has been the prime method for preparing soluble Toxoplasrna gondii antigens for use in serodiagnosis. The three methods most commonly used (lysis‐in‐water, sonication and freeze‐thawing) all yielded three antigenic peaks (4, 5 and 6) on crossed immunoelectrophoresis. Antigen 6 has been shown to be heat stable (56°C/I h) and appears to be a major antigen in the indirect haemagglutination test (IHAT). Saponin and octyl glucoside were found to be the most effective detergents for solubilization when used in combination, yielding between 7 and 11 antigens. Using a new triple‐staining technique, antigen 3 has been characterized as a glycoprotein, antigen 7 as a lipopolysacchiaride and antigens 1, 2, 4, 5, 6 and 8 to 11 as proteins. Molecular weight determination by gel filtration has been carried out and the majority of the antigens have a mol. wt of 105 to 1.5 × 105 daltons. Crossed immunoelectro‐focusing has shown that all the antigens are isoelectric at acidic pH. The findings of this preliminary investigation into the basic antigenic structure of T. gondii are discussed in relation to future work and the rational development of serodiagnostic tests.
Immunoprecipitation of biosynthetically‐labelled proteins from different Papua New Guinea Plasmodium falciparum isolates by sera from individuals in the endemic area
Authors: BROWN G.V. , ANDERS R.F. , STACE J.D. , ALPERS M.P. , MITCHELL G.F.
Published: October 2007

The human serum antibody response to Plasmodium falciparum infection in Papua New Guinea has been studied by electrophoretic analysis of immunoprecipitated biosynthetically‐labelled malaria proteins fro‐m three different isolates maintained in long‐term in vitro culture. Differences in protein antigenic composition in different lines have been described and simplified by examination of antigens recognized only by hyperimmune serum. An in vitro assay has been used to screen various human sera containing antimalarial antibody for their ability to inhibit parasite growth and the immunoprecipitation profiles of non‐inhibitory sera have been compared with those of a hyperimmune serum pool. In the discussion, emphasis is placed on the value of immunoprecipitation analyses using clinically‐defined sera with known in vitro function in the identification of antigens which may be responsible for the induction of host‐protective immunity.
Schistosomiasis from S. mansoni in mice: the relationship between acquired immunity and serum levels of lethal antibody
Authors: MOTA‐SANTOS T.A. , M. TOLEDO MARTA‐INEZ , CORREA M.C.R. , CORREA‐OLIVETRA R. , GAZZINELLI G.
Published: October 2007

Acquired immunity to Schistosoma mansoni induced by a primary infection with cercariae of one or both sexes was assessed in mice by the recovery of parasites of a challenge infection from the lungs or the liver. In addition, the antibody‐dependent complement‐mediated cytotoxicity against schistosomula in vitro was titrated in sera obtained from both groups of animals. The degree of immunity as detected by the lung recovery technique in mice infected with a mixture of male and female cercariae was variable and lower than 50%. In contrast, no immunity was observed in the group of animals infected with 40 ‘single‐sex’cercariae. The titre of lethal antibody in a pool of sera from these animals was about 10, whereas it was about 640 in a pool of sera from bisexually infected animals. Lethal antibody titres ranged from 20 to 120 for unisexual infection and 240 to 1920 for bisexually infected mice. In some cases a significant degree of immunity was detected by liver perfusion in mice with a primary unisexual infection. However, the lethal antibody titre of sera from mice with a 'single‐sex’infection remained low, even when the immunity was apparent.
Inhibition of adherence and cytotoxicity by circulating immune complexes formed in experimental filariasis
Authors: KARAVODIN LINDA M. , ASH L. R.
Published: October 2007

Summary Peritoneal exudate cells (PEC) from normal jirds (Meriones unguiculatus) showed adherence to Brugia pahangi microfilariae, and subsequent cytotoxicity in the presence of antimicrofilarial antisera. Heat inactiviation of the antisera diminished both adherence and cytotoxicity, but readdition of fresh normal jird sera only partially restored the reactions. Macrophages were the predominant adherent cell type. Circulating immune complexes precipitated with polyethylene glycol (PEG) from the sera of jirds with an 8‐month infection inhibited both of these reactions. Complement consumption by the precipitated complexes was found not to be the cause of inhibition. Blocking of adherence and cytotoxicity by circulating immune complexes may be preventing the trapping of microfilariae in vivo, and may play a role in the persistence of microfilaraemia in the jird.
Decreasing immunogenicity of developing schistosome larvae
Authors: SHER A. , BENNO D.
Published: October 2007

Summary Cercariae, skin stage schistosomula, and lung stage schistosomula of Schistosoma mansoni were attenuated by gamma irradiation and tested for their ability to induce protective immunity against cercarial challenge in C57B1/6J mice. The highest levels of resistance were induced by cercariae administered either percutaneously or intramuscularly. Skin stage schistosomula inoculated intramuscularly gave less protection while lung stage schistosomula from syngeneic donors were the least immunogenic. A similar ranking in immunogenicity was observed when the anti‐skin stage schistosomular antibody responses induced by the different parasite stages were compared. In contrast, none of the immunization protocols were found to stimulate antibodies capable of recognizing lung stage schistosomula. These results suggest that, as schistosome larvae mature from the cercarial to the lung stage, they undergo a substantial loss in immunogenicity. This change may help explain the failure of older larvae to be immunologically destroyed in infected hosts.
Phytohaemagglutinin reactivity in circulating peripheral blood lymphocytes during a Trypanosoma brucei infection: sequential studies in individual guinea‐pigs
Authors: LONGSTAFFE J. A. , TERRY R. J.
Published: October 2007

This study has analysed the response to phytohaemagglutinin of peripheral blood lymphocytes from guinea‐pigs infected with Trypanosoma brucei brucei. By this means it was possible to follow the response of individual animals throughout an infection. A culture method using whole blood permitted fewer cell manipulations and eliminated the necessity to supplement cultures with heterologous serum. Selection of appropriate strains of T.b. brucei produced a relatively chronic infection in guinea‐pigs. Results from this system indicate that, even late in the disease, significant mitogen reactivity still remains in some individuals. More significantly, these mitogen ‘responders’ controlled successive parasitaemic waves producing a fluctuating parasitaemia whereas the animals showing poor mitogen responsiveness—‘non‐responders’ failed to control successive waves and showed plateau parasitaemias.
Enhanced resistance to Plasmodium berghei in mice previously infected with Trichinella spiralis
Authors: NGWENYA B. Z.
Published: October 2007

Infection with Trichinella spiralis larvae greatly enhanced the resistance of adult mice against fatal infection with Plasmodium berghei given 10 and 30 days after T. spiralis infection. Mice infected with T. spiralis had a markedly activated mononuclear phagocytic system and significantly low reticulocyte levels at the time the mice were challenged with P. berghei. Therefore, the partially subdued parasitaemia and prolonged survival of Trichinella—Plasmodium‐infected mice may be attributed, in part, to macrophage activity and reticulocytopenia exerting a specific anti‐P. berghei effect. This study suggests the role of T. spiralis induced reticulocytopenia and activated macrophages as potential mechanisms in resistance to P. berghei infection.
Humoral responses against Trypanosoma brucei variable surface antigen are induced by degenerating parasites
Authors: SENDASHONGA CYRIAQUE N. , BLACK S. J.
Published: October 2007

An analysis was made of the inductive stimuli for anti‐T. brucei variant surface glycoprotein (VSG) responses and the role played by humoral immunity in trypanosome wave control. The first wave parasitaemia was influenced by the rate of parasite differentiation from rapidly dividing slender forms to short lived stumpy forms. Remission of first wave parasitaemia was caused by a humoral immune response against external determinants of surface expressed VSG. Anti‐VSG responses were accompanied by anti‐trypanosome plasma membrane responses and were followed by non‐specific responses. Responses appeared to be initiated by fragments of parasites on which VSG external determinants and plasma membrane antigens were accessible and were possibly accelerated and amplified by a trypanosome mitogen which was not VSG. The parasite fragments may have arisen as a result of degeneration of stumpy form but not slender form parasites.
Activation of the alternative pathway of bovine complement by Trypanosoma congolense
Authors: TABEL H.
Published: October 2007

Homogenates of Trypanosoma congolense and particulate and supernatant fractions thereof were, by two different techniques, shown to activate bovine complement via the alternative pathway. (1) All three preparations converted complement factor Bbov to its split product Bγ2 as demonstrated (a) qualitatively by immunoelectrophoresis and (b) quantitatively by radial immunodiffusion. (2) Lysis of guinea‐pig erythrocytes by bovine complement via the alternative pathway was inhibited by whole homogenates and particulate fractions of T. congolense organisms.
A comparison of saponin with other adjuvants for the potentiation of protective immunity by a killedPlasmodium yoeliivaccine in the mouse
Authors: BOMFORD R. , McCOLM A. A. , DALTON L.
Published: October 2007

The protective immunity conferred by subcutaneous injection of outbred CD‐1 mice with a killedPlasmodium yoelii(YM strain) vaccine was strongly potentiated by saponin. By adjusting the dose of antigen, the number of immunizations and the number of living parasites in the challenge infection, conditions were defined where antigen alone was non‐protective but 100% protection was obtained by the addition of saponin. Inbred BALB/c, CBA/CA and C57 Bl mice were much less responsive than the CD‐1 mice. The following adjuvants were compared with saponin: mineral oil emulsions (Freund's incomplete and complete adjuvants); Al(OH)3(Alhydrogel); bacteria and synthetic bacterial derivatives (Bordetella pertussis, Corynebacterium parvumand muramyl dipeptide); surface active materials (digitonin, vitamin A, Arquad 18, dimethyldioctadecyl ammonium bromide, and the polyene antibiotics, Nystatin and Amphotericin B). None of these adjuvants were as effective as saponin, although FCA, Al(OH)3and C.parvumaugmented immunity considerably. The possible reasons for the efficacy of saponin as an adjuvant for protozoal vaccines are discussed. TheP. yoelli/mouse system provides a sensitive and rapid screening assay for comparison of potential adjuvants suitable for use with a malaria vaccine.
Protective immunity and specificity of antibody responses elicited in cattle by irradiated Trypanosoma brucei
Authors: MORRISON W. I. , BLACK S. J. , PARIS J. , HINSON C. A. , WELLS P. W.
Published: October 2007

The level and specificity of antibody responses elicited in cattle by irradiated non‐infective Trypanosoma brucei were examined and related to the development of protective immunity. These responses were compared with those induced by infection and by inoculation with purified variable surface glycoprotein (VSG) in adjuvant. It was found that 107 or more irradiated trypanosomes inoculated intravenously into cattle conferred complete protection against challenge with 103 homologous trypanosomes 14 days later. Animals immunized with 106 organisms showed partial protection. Of the assays used for detection of antibody, neutralization of infectivity was slightly more sensitive than either the Farr assay or the immunofluorescence test which were both more sensitive than solid‐phase radioimmunoassay (RIA). Detection of specific antibody correlated with immunity, in that all animals inoculated intravenously with 106 or more trypanosomes developed neutralizing activity in their sera. The antibody responses after intravenous inoculation were consistently superior to those induced by the subcutaneous route. By carrying out blocking assays, most of the antibody elicited by irradiated trypanosomes was found to be specific for antigenic determinants on the VSG exposed on the surface of live trypanosomes. A similar specificity was found for the antibody induced during infection with T. brucei. Conversely, a large component of the antibody induced by purified VSG in adjuvant appeared to be directed against determinants on the VSG which are not exposed on live trypanosomes and are probably not involved in protective immunity.
Protective antibodies against erythrocytic stages of Plasmodium falciparum in experimental infection of the squirrel monkey, Saimiri sciureus
Authors: GYSIN J. , DUBOIS P. , DA SILVA L. PEREIRA
Published: October 2007

Serum and ascitic fluid from squirrel monkeys (Saimiri sciureus) inoculated with erythrocytic stages of Plasmodium falciparum were collected at different periods of the infection. Protection against P. falciparum was achieved by passive transfer of the sera or fluid recovered from animals after spontaneous or drug‐induced cure. Purified immunoglobulins from the ascitic fluid also conferred protection. In contrast, protective antibodies directed against erythrocytic stages of P. falciparum could never be demonstrated during the acute phase of infection in spite of the high titres of malarial antibodies detected by immunofluorescence. The comparative immunochemical analysis of antigens recognized by protective and non‐protective antibodies revealed quantitative differences which may be of use for the identification of antigens inducing protection.
Trypanosoma cruzi: deficient lymphocyte reactivity during experimental acute Chagas’ disease in the absence of suppressor T cells
Authors: KIERSZENBAUM F. , BUDZKO DELIA B.
Published: October 2007

Infection of mice with Trypanosoma cruzi has been shown to lead to an impaired ability of lymphocytes to proliferate in response to mitogenic stimulation which is manifested during the acute period of the disease. A possible involvement of suppressor T lymphocytes has been postulated by other authors and was investigated in this work as a part of our efforts to disclose the mechanisms underlying the immunologic deficiency. Spleen cells from acutely infected CBA/J mice readily exhibited unresponsiveness to stimulation with concanavalin A, phytohaemagglutinin or a bacterial lipopolysaccharide. However, these cells were unable to reduce the responses that normal syngeneic‐mouse spleen cells mounted to these mitogens when cultured together in equal proportions. Furthermore, removal of the Lyt 2.1‐bearing cells, known to include the suppressor T cell subpopulation, from infected mouse splenocyte suspensions, did not alter the deficient responsive status of the remaining cells. These results, together with the severe depletion of the T‐cell compartment which occurs in the spleens of animals acutely infected with T. cruzi, do not support an important role of suppressor T lymphocytes in the noted deficiency in lymphoid cell reactivity to mitogens. Reduced numbers of responder cells, intrinsic lymphocyte alterations or suppression by cells other than T lymphocytes remain plausible explanations to be explored.
Kinetics of expulsion of the nematode, Nippostrongylus brasiliensis, in mast‐cell deficient W/Wv mice
Authors: MITCHELL LESLIE ANN , WESCOTT RICHARD B. , PERRYMAN LANCE E.
Published: October 2007

Summary Mucosal mast‐cell hyperplasia is frequently observed in intestinal nematode infections and it has been suggested that mast‐cell responses to parasite antigens are involved in worm expulsion (self cure). To evaluate the importance of this mechanism, the course of infection and expulsion of Nippostrongylus brasiliensis was compared in mast‐cell deficient W/Wv and normal (+/+) mice. Initial infectivity rates were similar, but the subsequent kinetics of expulsion of adult worms differed principally in that the onset of expulsion in mast‐cell deficient mice appeared to occur 24–36 h later than that in normal mice. Expulsion was complete by the 14th day post infection in both W/Wv and normal mice. Worm fertility (as estimated by faecal egg output) also differed in W/Wv and normal mice, with maximal egg output in W/Wv mice occurring 24 h later than that in normal mice. Although a few mast cells were present in the intestinal mucosa and tongue of W/Wv mice, their numbers did not change during the course of infection with N. brasiliensis. In contrast, worm expulsion in normal mice was associated with a moderate increase in numbers of intestinal mast cells, commencing at the onset of expulsion and peaking several days after expulsion was completed.
Mechanisms of Schistosoma mansoni egg excretion: Parasitological observations in immunosuppressed mice reconstituted with immune serum
Authors: DUNNE D. W. , HASSOUNAH O. , MUSALLAM R. , LUCAS S. , PEPYS M. B. , BALTZ MARILYN , DOENHOFF M.
Published: October 2007

Summary CBA mice which had been deprived of their T cells by a combination of adult thymectomy and injection of rabbit anti‐mouse thymocyte serum failed to excrete as many Schistosoma mansoni eggs in their faeces as immunologically intact controls. This failure of parasite egg excretion was not obviously attributable to any marked change in the amount of faecal matter produced, or to a change in the size of the worm burden, or to the number or distribution of eggs in the tissues as a result of T‐cell deprivation. S. mansoni eggs freshly isolated from T‐cell‐deprived mice and injected intravenously into normal animals, induced lung granulomas which were the same size as those induced by injection of eggs from normal donors. The rate of S. mansoni egg excretion was not affected by the density of eggs in the tissues, in as much as there was a linear relationship between the number of tissue‐bound eggs and the number of eggs detected in the faeces. Treatment of infected mice with the immunosuppressant hydrocortisone acetate also induced a marked reduction in the rate of egg excretion. Injections of serum derived from chronically infected normal mouse donors increased the rate of egg excretion in both T‐cell‐deprived and steroid‐treated mice, but the degree of reconstitution obtained by daily serum injections was only partial relative to normal egg excretion rates. Treatment of infected normal or deprived serum‐treated mice with cobra venom factor to reduce serum complement C3 levels had no effect on the rate of S. mansoni egg excretion.
Site of expression of immunity to Naegleria fowled in immunized mice
Authors: THONG Y. H. , CARTER R‐F. , FERRANTE A. , ROWAN‐KELLY B.
Published: October 2007

Summary An experiment was performed which confirmed a previous finding that mice are protected against Naegleria fowleri infection by immunization with amoeba‐free supernatant from amoeba cultures. Histological observations suggested that this protection is expressed mainly at the nasal mucosa and possibly results from the combined effects of polymorphonuclear leucocyte‐mediated killing of the amoeba and mechanical elimination of the organisms by extensive shedding of necrotic epithelium.
Antibody‐dependent cytotoxicity of Trypanosoma cruzi antigen‐coated mouse cell lines by eosinophils and neutrophils
Authors: LÓPEZ A. F. , SANTOS R. RIBEIRO DOS , SANDERSON C. J.
Published: October 2007

Summary Eosinophils and neutrophils are shown to be cytotoxic against two syngeneic mouse cell lines cells when these are coated with T. cruzi antigen and anti‐T. cruzi antibody. Activity is detected within 5 h of incubation. Highest levels of cytotoxicity are obtained at antibody dilutions of 1:100 and 1:1000, while antiserum at 1:10 is shown to be inhibitory. Eosinophils show significant activity at an effector to target ratio of 5:1. No cytotoxicity occurs in the absence of either antigen, antibody or effector cells. This phenomenon may be a model for the tissue destruction in acute T. cruzi infection, where the lysis of trypanosomes may lead to antigen coating of host cells, followed by antibody‐dependent granulocyte‐mediated cytotoxicity of the host cells.
Suppression of primary and secondary antibody responses and inhibition of antigen priming during Babesia microti infections in mice
Authors: GRAY G. D. , PHILLIPS R. S.
Published: October 2007

Summary The antibody response to sheep red blood cells (SRBC) has been measured in C57B1 mice infected with the intra‐erythrocytic piroplasm Babesia microti. The primary antibody response is severely reduced or abolished when antigen is administered at the time of maximum parasitaemia. The secondary antibody response of infected mice, which had been primed with SRBC, is reduced but retains the characteristics of a secondary response. Mice injected with SRBC at maximum parasitaemia failed to become primed to that antigen: these mice gave a primary antibody response to a second injection of SRBC given after the infection had become sub‐patent. B. microti, therefore, can completely prevent the induction of memory, but only partially inhibit the expression of memory.
Role of macrophage‐processed antigen in a Plasmodium berghei model
Authors: PARASHAR ARUNA , SEHGAL S. , NAIK S. , AIKAT B.K.
Published: October 2007

Summary The present study demonstrates that malarial parasite could be processed by macrophages in vitro to release ‘super antigens’. These super antigens obtained from the peritoneal macrophages were more protective than those processed by the splenic adherent cells. BCG‐stimulated macrophages were also able to process the antigens efficiently and these antigens were even superior to those obtained from the unstimulated macrophages. These modified antigens were potent inducers of DFPS to malarial antigens. It is thus concluded that parasite antigens, processed in vitro, carry specific immunogenic potential and are able to protect the recipients to parasite challenge.
The athymic nude rat. IV. Immunocytochemical study to detect T‐cells, and immunological and histopathological reactions against Trichinella spiralis
Authors: VOS J.G. , RUITENBERG E.J. , BASTEN NETTY VAN , BUYS JANNIE , ELGERSMA ANNEKE , KRUIZINGA W.
Published: October 2007

Summary The anti‐parasite response was investigated after oral infection of athymic nude (rnu/rnu) rats and heterozygous (+/rnu) littermates with 1000 muscle larvae of Trichinella spiralis. No IgM, IgG and IgE antibodies were detected in serum of rnu/rnu rats. Expulsion of adult worms from the small intestine was prolonged (worms were nearly all expelled at days 14 and 91 in +/rnu and rnu/rnu rats respectively). The yield of muscle larvae in the carcasses of nude rats at day 91 was 33 times higher than in +/rnu rats. In contrast to the strong inflammatory reaction in the parasitized tongue of +/rnu rats, no infiltration was observed in rnu/rnu rats. Using an immunoperoxide method with monoclonal anti‐rat T‐cell antibody, no T cells were identified in spleen, mesenteric lymph node and Peyer's patches. These data support earlier studies that the nude rat lacks functional T cells. As the counts of connective tissue mast cells (CTMC), intestinal mast cells (IMC) and globule leucocytes (GL) in small intestine of uninfected rnu/rnu rats were equal or higher than in +/rnu rats, it is concluded that the origin of these cells is thymus‐independent. In contrast to +/rnu rats, infection of rnu/rnu rats induced no increase of CTMC, IMC or GL. Thus, these cells depend on T cells to undergo proliferation. Finally, results of this study were inconclusive whether IMC are precursors for GL, or that they represent independent cell populations.
Immunization of owl monkeys to Plasmodium falciparum with merozoites from cultures of a knobless clone
Authors: TRAGER W. , LANNERS H.N. , STANLEY H.A. , LANGRETH S.G.
Published: October 2007

Summary Aotus trivirgatus monkeys of karyotype 2 were treated as follows. Three received two injections of purified merozoites of a knobless (K‐) clone of Plasmodium falciparum with muramyl dipeptide as adjuvant; three received similar injections but with merozoites of a wild‐type knobby (K+) strain; three controls received MDP with human erythrocytes in the amounts estimated to be present as contaminants in the merozoite preparations. A month after the second injection all nine monkeys were inoculated with parasites of the wild‐type knobby strain from another infected Aotus. The monkeys that had received the K‐ material developed only extremely low infections markedly different from the infections in the controls. Of those that received K+ material, one died early with low parasitaemia, one was protected and one had the same level of infection as the controls. In the combined group of immunized animals, four out of six were protected.
The detection and measurement of coproantibodies to Nippostrongylus brasiliensis in rats following a primary infection
Authors: WEDRYCHOWICZ H. , MACLEAN J.M. , HOLMES P.H.
Published: October 2007

Summary Investigations were initiated to study the possible detection and measurement of coproantibodies in animals infected with a gastrointestinal nematode parasite. Faecal extracts, extracts of small intestinal mucosa and sera of rats infected with intestinal nematode Nippostrongylus brasiliensis were examined for total IgA, IgM and IgG levels and haemagglutinating and precipitating antibodies specific to parasite antigens over a 30‐day‐period following infection. It was found that in both faecal and mucosal extracts immunoglobulin concentrations increased after a primary infection. In faecal extracts there was a seven‐fold increase of IgA, a three to six‐fold increase of IgG and about a fifty‐fold increase of IgM. Haemagglutinins in faecal extracts detected by adult worm excretory‐secretory (ES) products and adult worm and infective larvae somatic extracts were observed from 3 days after infection (DAI). Haemagglutinins detected by ES products reached their highest titres on 11–12 DAI while those reacting with adult worm somatic extracts showed the highest level between IS and 19 DAI. A similar pattern of response was found in the antibody levels of the intestinal mucosa. Haemagglutinins detected in faeces during the first 12 DAI reacted with the same antigens as antibodies present in the sera at that time but coproantibodies from 18, 24 and 30 DAI were different from those circulating in sera at that stage of the infection. The results suggest that measurement of coproantibody levels may provide a convenient and useful index of local immune responses to gastrointestinal helminths.
Genetic association of murine susceptibility to Brugia malayi microfilaraemia
Authors: FANNING MARY M. , KAZURA J.W.
Published: October 2007

Summary The influence of host genetics on susceptibility of mice to Brugia malayi microfilariae and its possible mechanism were studied. There was a strain‐association for duration and peak level of microfilaraemia: CBA/CaJ, C3H/HeJ, DBA/1J, AuSs/J and A.Sw/Snhad a short duration (3–5 days) and low parasitemia (19–26 parasites/100 /il blood) compared to C57Br/cdJ, AKR/J, C57BL/6J, 129/J, BALB/cJ, DBA/2J, B10.D2/NSn, B10.D2/OSn and SJL/J(duration of 58–73 days, peak parasitaemia of 58–74 parasites/100 μl blood). Relative resistance to microfilariae was not related to the H‐2 complex as determined in studies of congenic C3H.B10 (H‐2b) and B10.H‐2k mice and their background strains. This trait was inherited in a dominant fashion and involved a single or small number of genes. Serum anti‐microfilarial antibodies reached highest levels in strains with a long duration compared to those with a short duration of parasitaemia (geometric mean titres of 1:13450 vs 1:284). The distribution of 5lCr‐labelled microfilariae among the livers, spleens, lungs and kidneys of a resistant (CBA/CaJ) and a susceptible (C57BL/6J) strain was similar. Transfer of immune lymphoid cells or sera between histocompatible (H‐2k) resistant CBA/CaJmice and susceptible C57Br/cdJ animals did not alter the duration of microfilaraemia.
Antibody‐dependent ingestion of P. falciparum merozoites by human blood monocytes
Authors: KHUSMITH S. , DRUILHE P.
Published: October 2007

Summary The binding of malarial antibodies to peripheral blood monocytes and the ability of these armed monocytes to attach to and ingest P. falciparum merozoites and schizont infected erythrocytes was evaluated by an in vitro assay. Monocytes from normal unsensitized subjects were preincubated with sera from individuals with various states of immunity to malaria and sera from normal controls. A marked difference in the level of merozoite phagocytosis was observed depending on immune status of the individuals whose sera were tested, but not on the antibody levels measured by fluorescence or precipitation tests. By protein‐A‐sepharose fractionation of these sera it appeared that the merozoite phagocytosis was mediated by immunoglobulin of the IgG class. Immunoglobulins eluted from these preincubated monocytes were able to bind to the parasites as detected by indirect fluorescent test. Similar assays performed with different strains and antibodies from various geographical areas indicated that the merozoite recognition and ingestion was not strain specific. The monocyte‐immunoglobulin co‐operation was effective in the phagocytosis of merozoites but not of schizont infected erythrocytes or normal erythrocytes. However, some degree of adhesion to the schizonts was recorded. These data seem to indicate that human blood monocytes can be specifically armed in vitro by cytophilic IgG with antimalarial specificity, and that such an effect is able to enhance markedly the clearance of free parasites but not of intact schizonts.
Activation of complement in C‐reactive protein positive sera by phosphorylcholine‐bearing component isolated from parasite extract
Authors: SUGANE KAZUO , OSHIMA TOMOO
Published: October 2007

Summary Phosphorylcholine‐bearing component levels in extracts of various parasites were determined by a capillary precipitin test using anti‐phosphorylcho‐line Ig A myeloma protein, TEPC‐15. Phosphorylcholine was demonstrated as a structural component not only in nematodes but also in trematodes and cestodes. The phosphorylcholine‐bearing component was isolated from an extract of Toxocara canis larvae using a TEPC‐15‐Sepharose 4B column. The component reacted with C‐reactive protein in sera to form one precipitin line in Immunoelectrophoresis. The component provided two Brilliant Coomassie Blue positive bands in SDS‐polyacrylamide gel electrophoresis. It reacted with C‐reactive protein to activate complement in serum.
The effects of indomethacin on in vitro peripheral blood mononuclear cell reactivity in human schistosomiasis
Authors: BARSOUM I.S. , TODD C.W. , HABIB M. , ALAMY M.A. EL , COLLEY D.G.
Published: October 2007

Summary The peripheral blood mononuclear cell (PBMN) proliferative responses of cells from patients with schistosomiasis were studied in the presence and absence of indomethacin in the culture medium. PBMN cultures were exposed to antigenic extracts of either adult S. mansoni worms (SWAP) or cercariae (CAP), and assayed for the incorporation of tritiated thymidine. More than 70% of the 48 patients studied with SWAP and the 40 patients studied with CAP, were not substantially effected by the addition of indomethacin to the cultures. The remainder (less than 30%) was augmented more than 50% by indomethacin and comprise a group which gave initially low responses to these antigenic preparations. Further analysis indicated that in some schistosomal patients the effect of an adherent suppressor cell population may, in part, be based on a prostaglandin‐mediated, indomethacin‐sensitive suppressive mechanism. However, the majority of patients, most of whom display adherent suppressor cells, are unaffected by indomethacin. Apparently, other adherent cell suppressor mechanisms are responsible for the regulation observed.
Immunoregulation of genetically controlled acquired responses to Leishmania donovani infection in mice: the effects of parasite dose, cyclophosphamide and sublethal irradiation
Authors: ULCZAK ORYSIA M. , BLACKWELL JENEFER M.
Published: October 2007

Summary On a B10 (Lshs) genetic background, the development of acquired T cell mediated immunity to Leishmania donovani infection in mice is under H‐2 linked genetic control. Following intravenous inoculation of 107 amastigotes three phenotypic patterns of recovery have been described: ‘early cure’ (H‐2r,s), ‘cure’ (H‐2b) and ‘non‐cure’ (H‐2d,q,f). In an attempt to determine the immunological basis for this H‐2 linked genetic control the effects of varying parasite dose (5 × 103 to 5 × 107 amastigotes) and of pre‐treatments with cyclophosphamide (50 or 200 mg/kgbody weight CY) or sublethal irradiation (100 or 550 rad) on the course of infection, and on circulating anti‐leishmanial IgG levels, were examined in strains representative of the three phenotypes: B10.D2/n (H‐2d), C57BL/10ScSn (H‐2b) and B10.RIII (H‐2r). It was found that with low parasite doses (5 × 103 or 5 × 104) ‘non‐cure’ mice presented a ‘cure’ profile whilst raising the dose (5 × 107) caused some perturbation of the normal self‐curing response in ‘cure’ (but not ‘early cure’) mice. The highest dose did not, however, lead to progressive disease in the genetically non‐cure strain. For the parasite dose experiments circulating anti‐leishmanial IgG levels were higher in the early cure and cure strains than in the H‐2d non‐cure strain. The higher doses of CY and sublethal irradiation administered prior to infection had a clear prophylactic effect on the non‐cure strain with some effect also observed in cure and early cure strains. This was thought to be due to deletion of the precursors of T suppressor (Ts) cells suppressing cell‐mediated immunity. Resolution of the liver parasite load in pre‐treated mice took place despite minimal or undetectable levels of circulating anti‐leishmanial IgG. Similarly, the earlier resolution of parasite load in pre‐treated cure and early cure mice occurred even though the antibody response was severely reduced. This suggests that the high antibody responses observed in early cure and cure strains do not normally mediate cure and may simply reflect the independent effect of H‐2 on T helper function for the humoral response.
Murine malaria: dissociation of natural killer (NK) cell activity and resistance to Plasmodium chabaudi
Authors: SKAMENE EMIL , STEVENSON MARY M. , LEMIEUX SUZANNE
Published: October 2007

Summary Striking differences in the resistance to P. chabaudi infection among different inbred mouse strains have previously been correlated with the level of both the spontaneous and the infection‐induced enhanced level of NK cell activity. We have examined this putative correlation in individual animals of backcross progeny derived from A/J (malaria‐susceptible, low NK cell activity) and BIO‐A (malaria‐resistant, high NK cell activity) progenitors. We have found that NK cell activity and resistance to malaria segregated independently. Furthermore, C57BL/6‐bg/bg mice which are deficient in NK cell activity were found to be as resistant to malaria as their heterozygous C57BL/6‐bg/+ siblings. We conclude that low NK cell activity, characteristic of A/J strain mice, is not a sufficient determinant of the exquisite susceptibility of these animals to infection with Plasmodium chabaudi.
Immune mechanisms in C57B1 mice genetically resistant to Trypanosoma congolense infection. II. Aspects of the humoral response
Authors: MACASKILL J.A. , HOLMES P.H. , WHITELAW D.D. , JENNINGS F.W. , URQUHART G.M.
Published: October 2007

Summary Some aspects of the humoral response in trypanotolerant C57B1 mice and susceptible A/J mice were investigated to determine the possible basis of trypanotolerance. When the hepatic uptake of 75Se‐labelled T. congolense by infected mice was measured as an index of antibody production, it was found that only C57B1 mice could remove circulating labelled parasites, this ability persisting for several weeks after infection. Estimation of the immunoglobulin concentrations in both strains of mice showed that C57B1 mice developed a pronounced IgM response during the first parasitaemic wave, while A/J mice did not. Over the same period the IgM concentrations in C57B1 mice initially fell, but recovered at the time of peak parasitaemia. In contrast, A/J mice showed a continual fall in total IgG concentrations in the circulation until death 10 days after infection. Finally, it was shown that during the initial rising parasitaemia, the plaque forming cell responses of both strains of mice to sheep red blood cells were normal indicating that neither strain of mice was immunosuppressed. Also, A/J mice vaccinated with irradiated T. brucei on day 4 and C57B1 mice vaccinated either on day 4 or day 60 of a T. congolense infection were able to mount an effective immune response to the vaccine, as judged by the hepatic uptake of radiolabeled parasites. All of the results indicate that the trypanotolerance of C57B1 mice depends, at least in part, on their more efficient antibody response.
Ultrastructural evidence for eosinophil‐mediated destruction of Angiostrongylus cantonensis transferred into the pulmonary artery of non‐permissive hosts
Authors: YOSHIMURA K. , UCHIDA K. , SATO K. , OYA H.
Published: October 2007

Summary Ultrastructural and cytochemical analyses were carried out on cellular reactions to the young adult worms of Angiostrongylus cantonensis surgically transferred into the pulmonary arteries of permissive (rat) and non‐permissive (rabbit and guinea‐pig) hosts. In permissive hosts, no appreciable cellular reactions could be found around worms throughout the course of the observations. By contrast, the infiltration of neutrophils along with eosinophils was observed around worms in non‐permissive hosts even at early stages (days 2 to 4). At day 7 and later, the prominent degranulation (solubilization of the whole granule or the matrix alone with preserved crystalloid, tubulovesicular structure formation, and vacuole formation containing lysosomal contents, etc.) of eosinophils, and subsequent release of the lysosomal contents on to the worm surface were noted. Discharge of large amounts of peroxidase on to the worm surface was also demonstrated. The worms were thus damaged and their cuticular fragments were frequently found removed. In addition to this, degenerative changes, such as lipid‐droplet and vacuole formations, were detectable in the hypodermis, somatic musculature and intestine of the parasites transferred into the non‐permissive hosts, as early as day 4 after transfer. These data suggest that eosinophils would serve as a potential effector cell for killing of pulmonary arterial A. cantonensis in non‐permissive hosts.
Increased leucocyte histamine release by Entamoeba histolytica antigen in patients with amoebic abscess of the liver
Authors: GIL‐RECASENS M.E. , CATS S. , LÓPEZ‐OSUNA M. , ROSENSTEIN Y.J. , ROMO R. , CERVERA J. , KRETSCHMER R.R.
Published: October 2007

Summary Leucocytes (basophils) from non‐atopic adult subjects living in an area highly endemic with Entamoeba histolytica release histamine in a dose‐dependent fashion upon in vitro exposure to an antigen of axenically grown E. histolytica (histolyticin). Leucocytes of patients with acute amoebic liver abscess were significantly more sensitive to this antigen than leucocytes of control subjects, including patients that had recovered from amoebic liver abscess. By comparison Concanavalin‐A induced histamine release found in patients with amoebic liver abscess and healthy controls suggest an immunological mechanism for histolyticin induced in vitro histamine release. This is also suggested by the inability of histolyticin to release histamine from leucocytes of healthy newborn infants and the significant fall in sensitivity to histolyticin following incubation of leucocytes in acid pH. Histamine and other mediators may contribute locally to the early intense inflammatory reaction observed in tissue invasion by E. histolytica.
A histocompatibility barrier to immunization against East Coast fever using Theileria parva‐infected lymphoblastoid cell lines
Authors: DOLAN T.T. , TEALE A.J. , STAGG D.A. , KEMP S.J. , COWAN K.M. , YOUNG A.S. , GROOCOCK C.M. , LEITCH B.L. , SPOONER R.L. , BROWN C.G.D.
Published: October 2007

Summary Histocompatibility may be a barrier to the infection of cattle when Theileria parva parva‐infected tissues or in vitro cultured macroschizont‐infected lymphoblastoid cell lines are used for immunization. By inoculating 103 and 105 infected cells into autologous recipients infection was achieved and immunity engendered. Cell lines inoculated into BoLA matched recipients did not produce patent infections but some recipients developed antibodies to the parasite and 3/5 were immune to challenge. No evidence of infection or immunity was found in BoLA half matched or mismatched cattle. This result suggests that there is an histocompatibility barrier to infection using T. p. parva‐infected lymphoblastoid cells.