Schistosoma mansoni: in vitro adhesion of parasite eggs to the vascular endothelium. Subsequent inhibition by a monoclonal antibody directed to a carbohydrate epitope.

Schistosoma mansoni eggs come into direct contact with the vascular endothelium, particularly in the postcapillary venules of the mesenteric tract (oviposition site). We investigated the adhesion of eggs to endothelial cells in a static in vitro assay and in a flow-based in vitro assay. Live S. mansoni eggs rapidly attached, in a time-dependent manner, to the human endothelial cell line ECV 304, but not KOH-treated eggs. Activation of ECV monolayers with interleukin-1 promoted live S. mansoni eggs adhesion. An in vitro flow-based assay of human umbilical vein endothelial cells (HUVEC) showed the influence of wall shear stresses on the attachment of eggs to endothelial cells, particularly under postcapillary venule shear stress conditions. Interleukin-1 activation of HUVEC promoted adhesion between live eggs and endothelial cells. Higher wall shear stresses were needed to obtain the detachment of eggs from activated endothelial cells than control cells. Preincubation of interleukin-1-activated HUVEC, in a static in vitro assay, with monoclonal antibodies specific for intercellular adhesion molecule-1, E-selectin, and vascular cell adhesion molecule-1 significantly decreased adhesion of live eggs. Previous studies have shown that a monoclonal antibody specific for a schistosome carbohydrate epitope abundant in eggs is related to the Lewis X antigen. In this study, the anti-Lewis X-specific monoclonal antibody was used for adhesion-inhibition assays. Preincubation of eggs with this monoclonal antibody significantly decreased adhesion of live eggs to interleukin-1-activated HUVEC cultured in vitro. These results suggest that surface adhesion molecules, expressed by endothelial cells under conditions of interleukin-1 activation, directly participate in egg adhesion and that egg carbohydrate antigens play an important role in live S. mansoni egg adhesion to the vascular endothelium.

[Immunofluorescence reaction of antibodies directed against the intestinal epithelium of Schistosoma mansoni. VI. Immunolocalization of a carbohydrate epitope at different developmental stages]. / Etude par la réaction d'immunofluorescence des anticorps dirigés contre l'épithélium intestinal de Schistosoma mansoni. VI. Immunolocalisation d'un épitope glucidique aux différents stades évolutifs.

In the course of previous works, we described an IgM monoclonal antibody directed to a carbohydrate epitope located on the gut epithelium surface of the Schistosoma mansoni adult worm. We provided evidence that this epitope was present in all stages of the parasite and was particularly abundant in eggs. The current work was performed in order to specify the epitope localisation, at each stage, by immunohistochemical techniques. The epitope appears to be located on the peripheral membranes of the adult worm, while it is produced by the alive miracidium in the eggs located in the tissues and subsequently spread out inside the periovular granuloma. Moreover, in adult worms, the observed structure presents itself as a soluble form in organic solvents; on the other hand, in eggs, the epitope was essentially found made of an hydrosoluble substance. These datas can explain why, in experimentally infected mice, the epitope is mainly determined in urines at the sixth week of infestation, when eggs are settled down in the tissues. Besides, the inhibition of the monoclonal antibody fixation by a pentose which contains the Lewis X antigen, painted out that the carbohydrate structure recognised by the monoclonal antibody could be the Lewis X antigen or a very closed structure.

Endothelium activation related increase of soluble intercellular adhesion molecule-1 in human schistosomiasis. Lack of correlation with serology.

Soluble intercellular adhesion molecule-1 (sICAM-1) level was measured in sera from 41 patients with Schistosoma mansoni schistosomiasis and compared with the sICAM-1 level in 41 healthy subjects. A significant increase in serum sICAM-1 was observed in patients with schistosomiasis compared with control subjects. As they were inhabitants of the French Antilles, the patients were, however, not settled in a malaria endemic zone, allowing this cause of sICAM-1 enhancement to be eliminated. No correlation was found between the level of sICAM-1 and the schistosomiasis serological titre. Such results favour the hypothesis of an activation of vascular endothelial cells due to egg deposition.

[Epidemiology of certain endemic parasitic diseases in the town of Guadalupe (Republic of Sao Tome and Principe). II. Other endemic parasitic diseases]. / Epidémiologie de certaines endémies parasitaires dans la ville de Guadalupe (République de Saõ Tomé et Príncipe). II. Autres endémies parasitaires.

Stool, blood and urine specimens have been collected from 380 inhabitants of all age groups living in the small town of Guadalupe in May 1992. The seroprevalence of Falciparum malaria (96%), toxoplasmosis (73.3%), have been measured.

[Epidemiology of certain endemic parasitic diseases in the town of Guadalupe (Republic of Sao Tome and Principe) I. Schistosomiasis intercalatum and intestinal worms]. / Epidémiologie de certaines endémies parasitaires dans la ville de Guadalupe (République de Saõ Tomé et Príncipe). I. Schistosomose à S. intercalatum et verminoses intestinales.

Schistosomiasis intercalatum in known to exist in Saõ Tomé since 1988, (Corachan et al.). It is transmitted by Bulinus forskalii, (Brown et al., 1989). Stool, blood and urine specimens have been collected from 380 inhabitants of all age groups living in the small town of Guadalupe close to the Agua Traz river and Agua Polino. The prevalence of schistosomiasis by detection of S. intercalatum eggs in a 10 mg stool thick smear (Kato technique) is 25.5%. An excreted Schistosoma polysaccharide antigen, detected by means of a monoclonal antibody (Ripert et al., 1992), is found in 49.1% of the urine samples. Patients voiding S. intercalatum eggs in stools have been treated with praziquantel (40 mg/kg body weight), as recommended by WHO Expert Committee on Schistosomiasis, but it might be wise to also treat persons excreting antigen in urine. The prevalence of intestinal helminthiasis, ascariasis (73.7%), trichuriasis (73.7%) and necatoriasis have been measured.

[Malaria indices, larval ecology and trophic activity of Anopheles mosquitoes in Djohong (Adamaoua, Cameroon) in the rainy season]. / Indices paludométriques, écologie larvaire et activité trophique des anophèles à Djohong (Adamaoua, Cameroun) en saison des pluies.

In Djohong in the wet season the prevalence of malaria is 17.5% for Plasmodium falciparum and 1.1% for Plasmodium malariae. In children 2 to 9 years of age the plasmodic index is 38.6% (mesoendemicity) for the children of the peasants and 9.4% for those belonging to other socioeconomical groups. In infants less than 12 months old, the plasmodic index is 9.3%, this relatively high rate corresponding to the high transmission period of the rainy season. Anopheles gambiae is the mosquito species most often found in the area (2/3 of the mosquitoes caught in the houses). The breeding sites in he surrounding of the houses are rainwater holes linked to human activity. At a larger distance from the houses, in the valley, the breeding sites are water holes borrowed for the retting of cassava tubercle or natural rock pools found in the basaltic shores of the Mbere river. The trophic activity of Anopheles gambiae and Anopheles funestus is high between 0 and 4 hours a.m. In October the mean number of anopheline mosquitoes bites per night per inhabitant is 33 inside the houses and 7 outside.

[Study by the immunofluorescence reaction of antibodies directed against antigens of the gut epithelium of Schistosoma mansoni. V. Modulation of granulomatous reaction around the egg under the influence of an IgM monoclonal antibody]. / Etude par la réaction d'mmunofluorescence des anticorps dirigés contre les antigènes de l'épithélium intestinal de Schistosoma mansoni. V. Modulation de la réaction granulomateuse autour de l'oeuf sous l'influence d'un anticorps monoclonal de classe IgM.

The periovular granulomatous reaction has been reduced in vivo by an IgM monoclonal antibody. The granulomatous reaction has been obtained either in unsensitized, or sensitized as well as immunized mouse. The granulomatous reduction could be explained by a decrease in egg viability, owing to the fact that the monoclonal antibody is lethal against an in vitro miracidium suspension.

Etude epidemiologique de l'onchocercose dans la vallee de la Bini (Adamaoua) Cameroun : prevalence de l'infestation et charge parasitaire

L'Enquete epidemiologique effectuee dans la vallee de la Bini montre que l'onchocercose touche l'ensemble de la population urbaine. Les resultats obtenus dans les villages sont sensiblement identiques. On note en effet que la prevalence parasitaire est de 57;3pour les hommes et de 50;3pour les femmes. Cette difference entre les sexes est encore accentuee par le calcul du nombre moyen de microfilaires par biopsie entamee. Celui-ci est de 55 pour les hommes et de 22 pour les femmes

[Evaluation of an indirect hemagglutination test for the serodiagnosis of amebiasis]. / Evaluation d'un test d'hémagglutination indirecte amibiase (HAI) pour le serodiagnostic de l'amibiase.

167 sera have been tested to appreciate the value of an indirect hemagglutination test (Amibiase HAI FUMOUZE) comparatively to an agglutination test of sensibilized particles of latex (Bichro latex Amibe Fumouze BLA) Amibiase HAI test comes out as sensitive and specific for the detection of antibodies in patients suffering from visceral amoebiasis. But some antibodies are also detected in patients with an antecedent of amoebiasis, as it is usually the case with some other techniques. A high positivity of the indirect hemagglutination test, and the concordance between the test HAI and the BLA one are in favour of a visceral amoebiasis. While lower rates or discrepancy between the two tests may evoke an hidden infestation in patients coming out or originated from endemic zones.

Etude epidemiologique du foyer de bilharziose a schistosoma intercalatum de Bata (Guinee Equatoriale)

Un antigene polysaccharidique caracteristique du genre schistosoma excrete dans l'urine est mis en evidence; avant et apres traitement par le praziquantel (40 mg/kg) dans la ville de Bata; ou un foyer de bilharziose a schistosoma intercalatum a ete identifie. Le test de detection urinaire de l'antigene met en jeu un anticorps monoclonal et fait appel a la technique d'inhibition de l'hemagglutination passive. Parmi les 779 sujets examines 145; soit 18;6 pour cent d'entre eux eliminent des oeufs de schistosoma intercalatum dans leurs selles et 305; soit 39;1 pour cent excretent de l'antigene dans les urines; ce qui dans la bilharziose traduit l'existence d'une profonde impregnation antigenique de l'organisme

Aspects epidemiologiques du paludisme dans la ville de Kumba (Cameroun-Province du Sud Ouest)

L'enquete paludometrique effectuee en fin de saison des pluies en octobre 1987 a Kumba; ville du Sud Ouest du Cameroun; a partir d'un echantillon de 804 sujets etabli montre la frequence des acces febriles et des automedications inadequates pratiquees. Elle apprecie le retentissement du paludisme sur la morbidite et la mortalite dans cette region forestiere. Plasmodium falciparum est l'hematozoaire le plus frequent; present sur 26;1 pour cent des lames examinees et responsable de 97;7 pour cent des infestations

Detection with a monoclonal antibody of a polysaccharide antigen, excreted in the urine, in the schistosomiasis intercalatum focus of Edea (Cameroon).

The detection in the urine specimens of a sample of the inhabitants of Edea of a polysaccharide antigen characteristic for the genus Schistosoma, with monoclonal antibody by means of the inhibition of a passive haemagglutination test, shows that this technique is very sensitive for measuring prevalence of schistosomiasis due to S. intercalatum. In Edea, looking for eggs in stool specimens gives a low prevalence rate of the disease because of the low parasitic load. The prevalence by age, according to the voiding of eggs, is evoluting parallel to the excretion of the antigen.

[Evaluation of malarial indices in the forest region of Djoum (southern Cameroon)]. / Evaluation des indices paludométriques dans la région forestière de Djoum (Sud Cameroun).

The authors report the results of a sample survey carried out in Djoum to evaluate the main malarial indexes among 0-15 years old children. These investigations suggest that malaria is hyperendemic in this forestry area, at the end of the dry season.

Effect of a mass treatment with praziquantel on the excretion in urine of a polysaccharide antigen used for diagnosis of schistosomiasis due to S. mansoni in Cameroon.

The detection in urine, with a monoclonal antibody, of an excreted polysaccharide antigen characteristic of the genus Schistosoma, allows evaluation of the effect of praziquantel used for mass treatment, in a focus of S. mansoni infection. Inhibition of the passive haemagglutination test, which was used for detecting the polysaccharide antigen in urine, is more sensitive for measuring prevalence than the determination of eggs in stools by means of direct examination and the formalin-ether concentration technique. Nine months after anthelminthic treatment, the percentage of inhabitants excreting antigen in urine diminished markedly, while the circulating antibody levels remained high. The test for detecting the antigen in urine seems to be the most efficient way to monitor the effect of mass treatment in intestinal schistosomiasis.

[Study of antibodies directed against antigens of the gut epithelium of Schistosoma mansoni using an immunofluorescence reaction. IV. Blocking action on immunity of an IgM monoclonal antibody]. / Etude par la réaction d'immunofluorescence des anticorps dirigés contre les antigènes de l'épithélium intestinal de Schistosoma mansoni. IV. Etude du pouvoir bloquant sur l'immunité d'un anticorps monoclonal de classe IgM.

The inhibitory effect on immunity is demonstrated by passive transfer experiments in mice. It can be shown in a secondary infection with Schistosoma mansoni and also in primary infection. The results indicate that blocking activity probably interfers with non specific immunity mechanisms.

Detection with a monoclonal antibody of an antigen, characteristic of the genus Schistosoma, excreted in the urine.

In the host, the antigen excreted by schistosomes in the circulating blood is concentrated in the urine. A mouse monoclonal antibody of the IgM class type lambda, directed against an epitope of the intestinal epithelium of the adult worm, is obtained. The antigen found in the urine of the host as well as the monoclonal antibody has been previously characterized. It is of a polysaccharidic nature, is thermostable and specific for the genus Schistosoma. The antigen is found at all stages of the life cycle and, particularly, in the egg where it is found in large amounts. Detection of the antigen is by means of inhibition of the passive haemagglutination test. There is a fundamental advantage in detecting the metabolic antigen excreted by schistosomes instead of looking for circulating antibodies. The antigen is directly released by the parasite itself, antibodies being, by contrast, produced by the host, indirectly therefore, and in a way that varies from one individual to the next. Collecting urine specimens is, for field workers, easier than obtaining blood from the inhabitants. The detection of the antigen in the urine is made a rather simple procedure since the antigen is concentrated by the kidney and free in urine, instead of remaining conjugated with antibodies like it is in the blood. When used in the Cameroon for the study of prevalence in two foci of schistosomiasis, intestinal (Nalassi Emana) and urinary (Barombi Kotto), the test detecting the antigen in urine gives good correlations with the parasitological examinations looking for eggs of S. mansoni and S. haematobium in feces and urine.

[Epidemiological aspects of malaria in 2 villages of the Manyemen forest region (Cameroon, southwest province)]. / Aspects épidémiologiques du paludisme dans deux villages de la région forestière de Manyemen (Cameroun-province du Sud-ouest).

In terms of parasitaemia in blood, the prevalence was 18.7% for Plasmodium falciparum, 10.5% for P. ovale and 1% for P. malariae in the villages of Mungo Ndor and Kokobuma. The plasmodial index of children from 2 to 9 years of age was 38.2% and the spleen index 26.6%, with a mean HACKETT score of 1.56. Malaria is thus meso-endemic in the region. The immunofluorescent test performed with a P. falciparum antigen was positive in 66% of the children in the same age group. Parasites were seen in 15% of new-born children. The malaria infection indices were higher in Mungo Ndor, which is located on the main road in the vicinity of the Manyemen hospital, than in Kokobuma. Morbidity and mortality due to malaria remain major problems in this part of the South-West Province, in spite of improving primary health care facilities and free chloroquine distribution. Anopheles gambiae is the main vector of malaria in the area, and transmission is interrupted only during the short dry season.

[Epidemiology of filariasis (onchocerciasis and bancroftosis) in the Tala-Mokolo region (Mandara Mountains of North Cameroon)]. / Epidémiologie des filarioses (onchocercose et bancroftose) dans la région de Tala-Mokolo (Monts Mandara-Nord Cameroun).

The effect of the bancroftian filariasis on the health of the inhabitants are minimal in the study area, where the prevalence of the disease (nocturnal microfilaremia) is 0.4% only. But skin snips harboring Onchocerca microfilariae are seen in 12.1% of the sample studied. Onchocerciasis skin lesions, low visual acuity and blindness are often seen in the villages where the prevalence is high, among inhabitants more than 40 years of age. Simulium damnosum is seldom seen in the area, except in the large streams and rivers like the mayo Tsanaga and the mayo Djingliya. Larvae and nymphae of this species hardly succeed in developing on the overspelling of the small dams, this being due more to a discontinuous run of the water in the overspilling than to a to high speed of the water.

[Evaluation of the clinical, parasitological and immunological indices of malaria in the Bonny's Bay area of Central Africa]. / Evaluation des indices cliniques, parasitologiques et immunologiques du paludisme dans la région de la Baie de Bonny en Afrique Centrale.

The authors report the results of 4 sample surveys carried out in Equatorial Guinea and Cameroon in the Bonny's Bay area, to evaluate the main malarial indexes. In rural and semi-rural areas one notice a high rate of fever attacks and splenomegaly. Parasitaemia is more important in rural areas than in urban areas and is decreasing where the therapeutic pressure is strong and long-lasting. Immunological indexes are high everywhere.