Humoral immune responses in human hepatosplenic schistosomiasis mansoni.

The development of hepatosplenic schistosomiasis in humans cannot always be related to the intensity of infection. A study was designed to identify different humoral immunologic responses to Schistosoma mansoni in patients with and without hepatosplenic disease. Twenty-four patients with active hepatosplenic disease were closely matched for age, sex, and fecal egg counts with twenty-four patients with only intestinal disease. A serum sample from each of these patients was tested for antibodies to the major soluble egg antigen (MSA1) by radioimmunoassay, for total and IgM antibodies to egg and worm antigenic preparations by ELISA, and for its ability to suppress antigen stimulated lymphocyte blastogenesis. No difference was found using these assays between the hepatosplenic and the intestinal schistosomiasis patients.

Serodiagnosis of human Schistosoma mansoni infections: enhanced sensitivity and specificity in ELISA using a fraction containing S. mansoni egg antigens omega 1 and alpha 1.

Six fractions of Schistosoma mansoni egg homogenate obtained by cation exchange chromatography were tested in an enzyme-linked immunosorbent assay (ELISA) for their efficacy in serodiagnosis of human S. mansoni infections. One cationic fraction (CEF6) containing egg antigens omega 1 and alpha 1, was found to be highly reactive with a S. mansoni positive reference serum pool. 94 of 95 sera from individuals infected with S. mansoni gave a positive reaction with CEF6, and no cross reactivity was obtained with this antigenic fraction and sera from donors infected with heterologous non-schistosome parasites and cases of avian cercarial dermatitis. Only 10 of 165 sera from patients with S. haematobium and three of 10 sera from patients with S. japonicum were positive with S. mansoni egg CEF6. In one group of patients from West Africa, examined both serologically and parasitologically at a six-monthly interval, the measurement of antibody to CEF6 provided a more sensitive diagnostic aid than stool examination.

Application of the enzyme linked immunosorbent assay (ELISA) for the serodiagnosis of Schistosoma mansoni infections in St. Lucia.

As part of our search for a serodiagnostic assay to replace the expensive and tedious stool examination in the diagnosis of Schistosoma mansoni infection, we have studied the sensitivity, specificity and quantitative features of an enzyme linked immunoassay (ELISA) using crude S. mansoni egg antigen preparation. Results of studies carried out in both London and St. Lucia indicate that the assay can give useful serodiagnostic information ranging from 82 to 99.5% sensitivity, depending on level of infection intensity and method of blood collection and 100% specificity in St. Lucian/St. Vincent populations. The St. Lucia study also showed that the assay could be operated in a qualitative form in an endemic area.

Preliminary investigation of the use of the enzyme linked immunosorbent assay (ELISA) in the serodiagnosis of mycetoma.

Antibody levels in a small group of Sudanese patients with clinically diagnosed mycetoma, and control groups were measured by countercurrent immunoelectrophoresis (CIE) and enzyme linked immunosorbent assay (ELISA). Antigens were prepared from the following organisms: Streptomyces somaliensis, Actinomadura madurae, A. pelletieri, Nocardia brasiliensis and Madurella mycetomi. Positive reactions were obtained in clinical cases against the homologous antigens in both CIE and ELISA; all heterologous and control sera negative in CIE but produced some reaction particularly against N. brasiliensis and M. mycetomi antigens in ELISA.

Serodiagnosis of mansonian schistosomiasis with CEF6, a cationic antigen fraction of Schistosoma mansoni eggs.

Studies of the host-parasite relationship of Schistosoma mansoni in mice revealed that the parasite's eggs were toxic to liver cells of immunosuppressed hosts. Attempts to identify the toxic egg constituent led to the isolation of a fraction CEF6 from crude egg homogenate by cation exchange chromatography. CEF6 contains two cationic antigens, omega 1 and alpha 1, the former being recognized as the putative hepatotoxin. In an initial assessment of its serodiagnostic potential in enzyme immunoassay (ELISA), CEF6 yielded an enhanced degree of sensitivity and specificity when compared with crude egg homogenate, and a subsequent 'blind' inter-laboratory collaborative study confirmed that in certain circumstances the use of a purified fraction such as CEF6 may be advantageous. We here review the experimental work leading up to the isolation of CEF6, and summarize the results so far obtained from its use as a diagnostic aid in human schistosomiasis.

A seroepidemiological survey in the Gezira, Sudan, with special reference to arboviruses.

A serological survey in the Gezira area of the Sudan confirmed that malaria and schistosomiasis were highly endemic. Of other parasitic infections amoebiasis was common but Toxoplasma was less than found in a previous survey. Poliomyelitis and measles infection were universal and there was an extremely high incidence of infection with hepatitis B. Of arboviruses infection with flaviviruses was frequent and more than with alphaviruses.

The serodiagnosis of human hydatid disease: 2. Additional studies on selected sera using indirect haemagglutination (IHA), enzyme linked immunosorbent assay (ELISA) and defined antigen substrate spheres (DASS).

Sixty-one serum samples selected on the basis of reactivity in the complement fixation (CF) and latex agglutination (LA) test, were further examined for sensitivity and specificity by indirect haemagglutination (IHA), enzyme linked immunosorbent assay (ELISA) and defined antigen substrate spheres (DASS). Twenty sera from healthy Europeans and 48 samples from patients with either schistosomiasis or trichinosis were also tested. Comparable levels of sensitivity were found between the CF and LA positive sera and IHA, ELISA and DASS. Of the CF positive LA negative group of sera, many were positive by DASS but only a few reacted in IHA and ELISA. Some cross reactivity was also observed in the schistosomiasis sera tested by IHA and ELISA.