Presence ofSchistosoma mansoni antigens in liver,spleen and kidney of infected mice: a sequential study

In the present study the kinetics of the uptake and deposition ofSchistosoma mansoni antigens in liver, spleen and kidney ofS. mansoni infected Swiss mice have been investigated in relation to duration of infection and infection dose (50, 100, 200 cercariae). The presence of antigen was studied with a direct immunofluorescence reaction on frozen sections of the organs, using a number of fluorescein isothiocyanate (FITC)-labeled antisera produced against various antigen preparations isolated from different life-cycle stages of the parasite. The presence of antigen was demonstrable with two of the antisera, directed against the circulating anodic antigen (CAA) and against total soluble egg antigen (SEA).CAA was demonstrable from 1 week post infection (p.i.) onwards in Kupffer cells in the liver, from 2–3 weeks p.i. onwards in macrophages in the marginal zones in the spleen and from 3 weeks onwards in kidney glomeruli. Immunofluorescence reactions on CAA in kidney glomeruli, however, were only weak positive until 12 weeks p.i., whereafter strong positive reactions were found.SEA was demonstrable from 5 weeks p.i. onwards in Kupffer cells in the liver and from 4 weeks p.i. onwards in macrophages of the spleen. In contrast to CAA, SEA was not detectable in kidney glomeruli.     

Nervous system ofSchistosoma mansoni cercaria: Organization and fine structure

As observed by transmission electron microscopy of serially sectionedSchistosoma mansoni cercaria, the nervous system is distributed throughout the three anatomic segments of the larva-i.e., the anterior organ (oral sucker), the body (midsegment), and the tail. The central ganglion, a neuropile surrounded by cell bodies, is located in the anterior area of the body segment. It tapers anteriorly into two lobes from which a pair of anterior central nerve trunks extend longitudinally. The posterior region of the central ganglion tapers into a pair of nerve trunks (posterior central nerve trunks). Twelve peripheral nerve trunks are evenly distributed around the ganglion. Six trunks course anteriad (anterior peripheral nerve trunks) and six course posteriad (posterior peripheral nerve trunks). A pair of dorsal and ventral nerve trunks, positioned opposite each other, extend the length of the tail. All nerve trunks are unsheathed. The nervous system contains three types of vesicles. Type I vesicles average 47.66±2.57 nm in diameter, vary in electron density, and have electron-lucent peripheries. Type II vesicles have a mean diameter of 18.41±2.57 nm, are electron-lucent and are concentrated mostly in the presynaptic area of the synaptic and neuromuscular junctions. The mean diameter of Type III vesicles is 57.47±16.08 nm. They are electron-dense and are concentrated mostly in the tegumental ciliated papillac and their accompanying dendrites. Two types of synaptic junctions are present. Type1 synapse has dense material incorporated in its postsynaptic membrane, while Type2 synapse has dense material of various dimensions incorporated in its presynaptic membrane and usually in its postsynaptic membrane. Synaptic and neuromuscular junctions are similar.     

Comparison of two egyptian strains ofSchistosoma mansoni in hamsters

In human infection withSchistosoma mansoni from Beni-Suef, the eggs were encountered more frequently in the urine of patients than in infection withS. mansoni from Giza, where eggs were passed into the stool. A comparative study of the two strains ofS. mansoni from Beni-Suef and Giza has been carried out in golden hamster. Consistent strain differences were observed. The Beni-Suef strain proved to have lower worm recovery and different egg distribution patterns in tissues of infected hamsters. Worms of both sexes of this strain were larger in size and required a longer period to reach maturity. Hence, the prepatent period was prolonged. Significant differences between the two strains were also noted in the number of eggs per worm. A lower mortality rate and a longer survival time were encountered in hamsters infected with the Beni-Suef strain.This work was supported by the Naval Medical Research and Development Command, NMC, NCR, Bethesda, MD. Work Unit No. 3M161102BS10.AA421     

The immunopathology ofSchistosoma mansoni granulomas in human colonic schistosomiasis

Summary The immunopathology ofSchistosoma mansoni infection was studied in colonic biopsies obtained from 14 patients with established schistosomiasis. The characteristic lesions of this parasitic infection are mainly induced by the presence of living eggs in the tissue. Different types of lesions can be present simultaneously. The earliest lesions contain T-lymphocytes as well as accessory cells around living eggs. They transform into granulomas composed of eosinophils, T-lymphocytes, a few B-lymphocytes and large mononuclear cells expressing major histocompatibility (MHC) class II antigens. These cells are also Mac 387 positive. This means that they are monocytes/macrophages freshly recruited from the blood. In other, probably older, granulomas, MHC class II positive cells tend to disappear and the centrally located multinucleated giant cells are negative for antibodies directed against MHC class II antigens. It appears thus that the composition of the granulomas in schistosomiasis is variable. The lesions may have characteristics of cell-mediated immunity and/or of a foreign-body reaction. Contrary to what is often seen in Crohn's disease or intestinal tuberculosis no major hyperplasia of the lymphoid tissue is observed in the colon in association withS. mansoni infection.     

Immunizing potential of ultraviolet-attenuated cercariae ofSchistosoma mansoni in rodent hosts

Schistosoma mansoni cercariae attenuated with ultraviolet (UV) irradiation (254 nm) at a dose of 18 mJ/cm² induced partial resistance against a homologous challenge in male ICR mice and male Hartley guinea pigs. The reduction in the adult worm burden was 51% and 37%±13%, respectively. On the other hand, male and female Mongolian gerbils (Meriones unguiculatus) vaccinated with UV-attenuated cercariae exhibited marginal resistance (13%±9% and 22%±10%, respectively). This raises the possibility that gerbils might have an unknown immune-characteristic nature. The usefulness of UV-attenuated cercariae is discussed with respect to the control of the disease.     

Stereoscan observations of the miracidium and early sporocyst ofSchistosoma mansoni

Summary Whole miracidia ofSchistosoma mansoni, miracidia vibrated in an ultrasonic cleaner, and the miracidium-sporocyst transition were studied in the steroscan electron microscope. After vibrating, the cilia broke off near the bases and the epidermal cella, intercellular ridge and sensory structures were revealed. The apical papilla had a folded surface with penetrating sensory cilia. The number of epidermal cells varied between 17 and 22. The lateral papillae appeared as bulbous projections on either side between the first and second tiers of epidermal cells. There was a ciliated pit nerve ending close to each lateral papilla. A few ciliated pits were found between the cells in the first tier, and up to twelve ciliated pits with long cilia could be found between the second and third tiers. Miracidia placed in haemolymph fromPlanorbarius corneus cast off the apical ciliated part of the epithelial cells, and large scars appeared where the ciliated plates had been. Later, the syncytial intercellular ridge dispersed throughout the surface of the mother sporocyst, and small cytoplasmic knobs appeared on the surface. The apical papilla and the lateral papillae were still observed a few hours after shedding the ciliated plates, but the ciliated pits disappeared shortly after the ciliated plates were lost.     

The energy metabolism ofSchistosoma mansoni during its development in the hamster

A detailed study was made of the changes in the carbohydrate metabolism ofSchistosoma mansoni occurring during both the penetration of the skin of a hamster and the subsequent development of the schistosome in the lung, liver, and mesenteric veins of the host. During infection, within a few hours a transition occurs from a fully aerobic to a largely anaerobic energy metabolism. By 5 h postinfection, about 6% of carbohydrate breakdown occurs in the aerobic reactions of the Krebs cycle, whereas the rest occurs in the anaerobic formation of lactate. The contribution of aerobic processes to carbohydrate breakdown remains at this level of 6% until 3 weeks postinfection and then gradually declines to the adult level of 2.5%. Measurement of the protein content of developing schistosomes shows that an exponential growth occurs over a 15-day period after the arrival of the schistosomes in the liver (days 11–25 postinfection). During this period the protein content of the parasites increases about 100-fold, but despite this change in size, no major changes occur in the end-product pattern of carbohydrate breakdown. We conclude that during this period the rate of oxygen diffusion into the tissues is not a limiting factor for aerobic metabolism. A limited diffusion of oxygen may play a role in the decreasing contribution of aerobic processes during the later stages of maturation of the schistosomes.     

Immunological characterization of human glomerular basement membrane antigens.

Normal human glomerular basement membrane (H-GBM) was solubilized by collagenase and subjected to crossed immunoelectrophoresis with rabbit antibodies against H-GBM. Seven precipitates appeared with the mobility of alpha, beta, and gamma globulins. Only two of these precipitates might be specific for GBM, since the other precipitates disappeared after absorption of the antiserum with liver and placenta. In normal human urine one precipitate, cross-reacting with one of the H-GBM precipitates, was found; this precipitate could also be demonstrated in human placenta and liver.     

Immunological characterization of novel secreted antigens of Mycobacterium tuberculosis

Proteins secreted by Mycobacterium tuberculosis are targets of host immune responses and as such are investigated for vaccine and immunodiagnostics development. Computer-driven searches of the M. tuberculosis H37Rv genome had previously identified 45 novel secreted proteins. Here, we report the characterization of these antigens in terms of specificity for the M. tuberculosis complex and the ability to induce human immune responses. BLAST homology searches and Southern hybridization identified 10 genes that were either specific for the M. tuberculosis complex or found in only two nontuberculous mycobacterial species of minor medical significance. Selected recombinant proteins were purified from Escherichia coli cells and tested for the ability to elicit antibody responses in tuberculosis patients. Reactivity of the serum panel was ' 36% with at least one of five novel proteins (Rv0203, Rv0603, Rv1271c, Rv1804c and Rv2253), 56% with the 38 kDa lipoprotein, a M. tuberculosis antigen known to be highly seroreactive, and 68% with a combination of Rv0203, Rv1271c and the 38 kDa antigen. Thus, at least five novel secreted proteins induce antibody responses during active disease; some of these proteins may increase the sensitivity of serological assays based on the 38 kDa antigen.     

Studies on experimental mixed infections ofSchistosoma mansoni andS. haematobium in hamsters

Golden hamsters were superinfected simultaneously with 100Schistosoma haematobium cercariae, 1 and 3 weeks after initial infection with 100S. mansoni cercariae. Results indicate that there was a higher degree of resistance to superinfection withS. haematobium at 1 week following initial infection withS. mansoni than that produced in the other two superinfections. This resistance was evidenced by a reduction in the number and size of worms of both species, decrease inS. haematobium egg extrusion per female and by a striking deviation in the egg distribution pattern of both species. Such an early host resistance was not recorded in previous works. Cross-mating was observed but no hybridization took place and the eggs produced were hatchable and typical of their species.     

Chlorpromazine,other amphiphilic cationic drugs and praziquantel: effects on carbohydrate metabolism ofSchistosoma mansoni

The effects of the amphiphilic cationic drugs chlorpromazine, imipramine, amitriptyline, propranolol and fluoxetine and praziquantel were investigated on glucose uptake and lactate excretion ofSchistosoma mansoni. While praziquantel enhances glucose uptake and lactate excretion at a concentration of 10^–7 M, all the other drugs exert the same effects at concentrations above 10^–5 M. Generally, a constant molar ratio of 12 is found between glucose uptake and lactate excretion. Above 10^–5 M, praziquantel inhibits glucose uptake and lactate excretion. Similar effects are caused by amphiphilic cationic drugs at 10^–3 M. Pre-incubation ofS. mansoni with 10^–5 M praziquantel completely abolish the stimulation of carbohydrate metabolism by serotonin and by 5×10^–5 M chlorpromazine or fluoxetine.The action of praziquantel onS. mansoni resembles that of amphiphilic cationic drugs with respect to their influence on carbohydrate metabolism. This, together with data obtained from electrophysiological and electron microscopic studies, provides evidence for the hypothesis that praziquantel exerts its effect by interacting with membrane structures.     

Immunological features of idiopathic Addison''s disease: characterization of the adrenocortical antigens

The antibodies in the sera of two patients with idiopathic Addison's disease, one reacting specifically with adrenocortical cells, the other with the various cell types which produce steroid hormones, have been found to be predominently IgG. The behaviour of the two antibodies in complement-fixation tests is in agreement with their reactivity, reported in the previous paper, in immunofluorescence tests.

Cell fractionation studies suggest that both adrenal antigens are associated with the microsomal fraction. The biochemical properties of the antigens are consistent with the view that they are lipoproteins, possibly with associated carbohydrate. While the properties of the adrenal antigens are generally similar to those of the thyroid and gastric parietal cell organ-specific autoantigens, they differ from these, and from each other, in their susceptibility to destruction by certain enzymes and chemical treatments.

     

Immunoelectron microscopical localization of a circulating antigen in the excretory system ofSchistosoma mansoni

In this study the excretory system ofSchistosoma mansoni was ultrastructurally examined with a recently described monoclonal antibody (mAb) against a circulating antigen. In previous studies this mAb was found to have affinity for the excretory system. Strong immunoreactivity was found on the flagella of the flame cells and of the collecting ducts throughout the worm. The eggshell and the space between the miracidium and the eggshell showed strong reactivity with a declining gradient towards the exterior, suggesting a secretion process. In cercariae, immunoreactivity was restricted to the tegument, whereas in schistosomula the labeling pattern resembled that of the adult worm, demonstrating positive reactivity of the flame cells and no immunostaining of the tegument. This stage-dependent differential expression of different antigens in the excretory system and in the tegument could suggest a maturation process of the excretory system.     

Autoantibodies to tumor-associated antigens as biomarkers in cancer immunodiagnosis

Cancer sera contain antibodies that react with a unique group of autologous cellular antigens called tumor-associated antigens (TAAs), and therefore these autoantibodies can be considered as reporters from the immune system, to identify authentic TAAs involved in the malignant transformation. Once a TAA is identified, different approaches would be used to comprehensively characterize and validate the identified TAA/anti-TAA systems that are potential biomarkers in cancer immunodiagnosis. In this manner, several novel TAAs such as p62 and p90 have been identified in our previous studies. p62, a member of IGF-II mRNA binding proteins (IMPs), is an oncofetal protein absent in adult tissues, the presence of anti-p62 autoantibodies relates to abnormal expression of p62 in tumor cells. p90 was recently characterized as an inhibitor of the tumor suppressor PP2A (protein phosphatase 2A), and an autoantibody to p90 appears in high frequency in prostate cancer. The present review will focus on the recent advances in studies mainly associated with these two novel TAAs as biomarkers in cancer immunodiagnosis.     

Detection of tumor antigens with monoclonal antibodies: immunopathology and immunodiagnosis.

The immunocytochemical demonstration, using monoclonal antibodies, of diverse cellular constituents has improved our understanding of many aspects of oncology. This review will focus on this approach to facilitate the detection of human tumors, improve their histological classification and provide functional parameters with potential aetiological, prognostic and/or therapeutic value.     

Immunological and chemical characterization of the extracellular antigens from Corynebacterium vaginale.

Supernatants from 72-h peptone-starch-dextrose broth cultures of Corynebacterium vaginale contained significant quantities of three extracellular, soluble antigens (ESA). The ESA were concentrated and partially purified by dialysis followed by ammonium sulfate and ethanol precipitation. Diethylaminoethylcellulose columns were used to isolate two of the three ESA. The ESA were shown to be similar to antigens found on whole C. vaginale cells. Absorption studies indicated that the cell antigens are located at, or near, the surface. On the bases of heat stability, resistance to protease treatment, concanavalin A binding activity, and susceptibility to periodate, it appears that all three ESA are polysaccharide or glycoprotein in nature.     

Gel-filtration chromatography of Salmonella protein antigens and their implication in immunodiagnosis

Crude Barber protein (Bp) antigens were prepared from Salmonella typhi, S. krefeld and S. derby by an original method that has been described previously. These antigens were subjected to gel-filtration chromatography using Sephadex G-200. A sharp peak that eluted together with the void volume was thus separated from a broad second peak that eluted from the column at positions equivalent to 118,000 to 12,000 daltons. The proteins eluted in the latter peak were arbitrarily divided into 5 fractions and, together with the first peak, subjected to polyacrylamide gel electrophoresis and immunoprecipitation with both homologous and heterologous rabbit antisera. The extent of immunological cross reactivities was determined by enzyme-linked immunosorbent assay. The preliminary results obtained by this technique showed species-specific protein antigens to have molecular weights ranging between 36,000 and 68,000 daltons.     

Immunofluorescent localization ofSchistosoma mansoni circulating cathodic antigen in tissues of infected mice using monoclonal antibody

In the present study the kinetics of the uptake and deposition of the major circulating cathodic antigen (CCA) ofSchistosoma mansoni in liver, spleen, and kidney ofS. mansoni infected Swiss mice was investigated in relation to the duration of infection and infection dose (50, 100, 200 cercariae). The presence of antigen was studied with a direct immunofluorescence reaction on frozen sections of the mouse organs, using a fluorescein isothiocyanate (FITC)-labelled mouse IgM monoclonal antibody recognizing a repeating epitope of CCA.CCA was demonstrable from 2 weeks post infection (p.i.) onwards in Kupffer cells in the liver, from 3–4 weeks p.i. onwards in macrophages in the marginal zones in the spleen and from 8 weeks p.i. onwards in kidney glomeruli. The immunofluorescence reactions on CCA in kidney glomeruli, however, remained relatively weak.