Antibody isotypes in human schistosomiasis mansoni.

The natural infection of a community with the hookworm Necator americanus induces a vigorous humoral response to both larval and adult parasite antigens. This response occurs in all five human antibody isotypes, and data are presented to show that, at the population level, isotypes respond differently, following chemotherapy and during reinfection, to changes in antigen stimulation. The differential response probably reflects the fact that the parasite, during the course of its life cycle, presents different amounts of antigens at different anatomical locations. It is suggested that IgG and IgM responses against adult excretory-secretory (ES) products most accurately reflect the efficacy of chemotherapy, and the load of resident adult infection, while IgG responses against larval somatic antigens reflect continuous exposure to infection. These hypotheses should now be tested, at the level of the individual, in a longitudinal manner using more closely spaced sampling intervals. This repetitive sampling, and the inclusion of a measure of the exposure of the population to infective stages, will allow more definitive conclusions to be made about the role of the immune response in controlling worm burdens.

Ulcerative colitis (UC), a severe chronic inflammatory disorder of the colon, is one of the inflammatory bowel diseases (IBD) that affects humans and several domestic animal species, including cats and dogs. Helminth infections and autoimmune diseases are inversely correlated, as explained by the hygiene hypothesis, which suggests that IBD is infrequent in countries where helminth infections are common but more prevalent in developed nations. This study investigated the therapeutic and prophylactic potential of Trichinella spiralis (T. spiralis) antigens in an experimental colitis model for IBD. Mice were divided into eight groups: normal model, colitis model, larval antigen prophylaxis, adult antigen prophylaxis, larval antigen therapeutic, adult antigen therapeutic, larval antigen prophylaxis and therapeutic, and adult antigen prophylaxis and therapeutic. Colitis was induced intrarectally by administering a single dose of 0.2 ml of acetic acid, except in the healthy group, which received PBS (0.2 ml). The mice were euthanized 12 days after colitis induction. The therapeutic and prophylactic potential of T. spiralis antigens were assessed through colitis severity and histopathological, immunological, and immunohistochemical examinations. The results showed a significant reduction in Disease Activity Index (DAI), an increase in goblet cells' acidic mucin levels, reduced iNOS and TNF-α expression, and decreased serum levels of IFN-γ and IL-10 cytokines in Groups IV-VIII compared to the colitis model, particularly in the group that received adult worm antigen both prophylactically and therapeutically. This study demonstrated that T. spiralis antigens, especially from adult worms, had protective and therapeutic effects on experimental colitis, with a superior effect when administered both before and after colitis induction by reducing inflammation and modulating the immune response. Thus, T. spiralis antigens may improve disease outcomes and provide a novel treatment approach for ulcerative colitis.

A serum IgG response to Strongyloides papillosus infection was analysed in rabbits. IgG production was induced against 30-200 kDa larval somatic antigens and 21-160 kDa adult excretory/secretory (ES) antigens at 4 weeks postinfection. No immunoreactivity was detected between sera of infected animals and any proteins of larval ES and adult somatic antigens. Protection against larval challenge infection was investigated in rabbits immunized by primary infection and by intradermal inoculations of larval somatic and adult ES antigens. Primarily infected animals had 90% fewer or less worms from day 2 onwards after challenge, and lower faecal egg outputs after challenge, when compared with those in susceptible animals. Immunization with larval somatic antigens induced effective protection, showing 52.6-81.5% reductions in worm recovery from day 5 onwards after challenge, and lower faecal egg outputs after challenge. Systemic immunization with adult ES antigens failed to protect the animals against challenge. The possibility that resistance to S. papillosus reinfection is performed on the killing of migrating larvae in the early stages of infection is discussed. Systemic immune responses to larval somatic antigens might play an important role in the resistance.

The sensitivity and specificity of crude and affinity-purified antigens of Clonorchis sinensis obtained from the infected rabbits were studied. Stage-specific antigenic proteins from the eggs, metacercariae and adult worms were characterized by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and enzyme-linked immunosorbent assay (ELISA) The results were as follows: The antibody-binding antigen (ABA) purified from whole worm crude antigen (WWA) by CNBr-activated Sepharose 4B affinity chromatography made 4 specific bands against rabbit anti-sera on Ouchterlony gel diffusion plate, while WWA made 7 bands. Major WWA protein bands by SDS-PAGE were found at 16,300-18,500 and 28,000-29,000 daltons, while major ABA protein bands were at 18,000-21,000 and 29,000-31,000 daltons. The reactivity of ABA with rabbit anti-sera in ELISA was remarkably less sensitive than that of WWA. Molecular weights of egg antigen (EGA), metacercarial antigen (MEA) and adult worm antigen (WWA) of C. sinensis ranged from 15,000-200,000 daltons, 15,000-100,000 daltons and 11,000-80,000 daltons, respectively. Major WWA proteins consisted mainly of polypeptide bands of low molecular weight, less than 31,000 daltons, while those of EGA and MEA consisted of higher molecular weights than 30,000 daltons. The ELISA reactivities of WWA to rabbit anti-sera were remarkably greater than those of MEA. EGA showed negative reaction throughout the experiments. WWA showed higher optical density (O.D.) than 1.0, when reacted with rabbit anti-sera obtained at 4-6 weeks after the infection. In the rabbit anti-sera later than 12 weeks after the infection, the O.D. reacting with WWA showed a plateau without variation. MEA showed relatively low O.D. values (<0.6), when reacted with anti-sera from lightly infected groups throughout the experiments, although there were some weak positive cases (O.D.>0.6) in heavily infected groups. MEA reacted with rabbit anti-sera showed negative results on Ouchterlony gel diffusion plates. Summarizing the above results, it is suggested that the whole worm antigen prepared from the adult worms of C. sinensis is most highly antigenic. However, this antigen might reveal cross reactions with other trematodes such as Paragonimus westermani, therefore, purification of antigenic proteins from the crude antigen is essential to increase the sensitivity and specificity for the immunodiagnosis of clonorchiasis.

BackgroundCirculating lymphocytes are essential for the immune response to helminth infections, as they secrete cytokines and thus coordinate subsequent immunological processes. In canine angiostrongylosis, a potentially fatal disease caused by the metastrongylid nematode Angiostrongylus vasorum, the underlying immune mechanisms driving disease progression remain poorly understood despite the severe clinical consequences. Canine peripheral blood mononuclear cells (PBMCs) were isolated from healthy dogs and stimulated with three different antigens of A vasorum, including adult excretory-secretory products (ESP), adult full-worm somatic antigen, and first-stage larval (L1) somatic antigen. Temporal dynamics and magnitude of relative cytokine expression (IFNγ, TNF, IL-4, IL-6, IL-10, IL-13) was evaluated after 4 h, 24 h, and 5 days of antigen exposure via quantitative reverse transcription PCR. To determine whether the cytokine expression changes translated into shifts in circulating mononuclear cell subsets or proliferative activity, phenotypic characterisation by flow cytometry was conducted after a 72 h stimulation with L1 antigen or ESP, and compared to unstimulated controls.ResultsEarly responses varied across antigen types, with ESP promoting a regulatory cytokine profile with modest upregulation of IL-4, IL-6, and IL-10, and downregulation of IFNγ, TNF, and IL-13. Adult antigen induced increased expression of all examined cytokines, while L1 antigen triggered the strongest inflammatory response compared to the other antigens. At 24 h, all responses were amplified, particularly those to L1 and adult antigen, and showed a shift towards a Th2 cytokine profile with increased IL-4 and IL-13 expression. By five days, IL-4 and IL-13 remained predominant. No change in the relative abundance of major immune cell populations (CD4⁺ T cells, CD8⁺ T cells, B cells, neutrophils, monocytes, and CD14⁻ CD22⁻ antigen-presenting cells) was observed in flow cytometry following stimulation. However, a notable increase in Ki67 expression, a marker of cell proliferation, was detected in CD8⁺ T cells after L1 antigen stimulation.ConclusionsDistinct cytokine profiles elicited by different A. vasorum antigens suggest that the parasite’s modulation of host immunity and induction of stage-specific responses are key to persistence and clinical presentation of canine angiostrongylosis. Further investigation into the antigenic components and immune pathways may lead to tailored therapies, improved clinical management, and to a deeper understanding of stage-specific aspects of helminth infections.

We studied the antigens of adults and third-stage larvae of the meningeal worm, Parelaphostrongylus tenuis, in an attempt to identify potential serodiagnostic molecules for this important infection of wild ungulates. Soluble extracts of P. tenuis adult worms and third-stage larvae were separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and two-dimensional (2D) electrophoresis and analyzed by immunoblotting using purified rabbit anti-P. tenuis immunoglobulin G (IgG). The IgG antibodies were obtained from animals immunized with P. tenuis adult worm or third-stage larva soluble extract and serum from elk infected with P. tenuis. Out of more than 75 antigens (as shown by 2D electrophoresis and immunoblotting), 7 antigens from adults (four 170-120-kD molecules with isoelectric points between 6.0 and 6.6, two 55-kD molecules with isoelectric points of 5.6 and 5.8, and one 13-kD molecule) and 2 antigens from third-stage larvae (one 25-30-kD molecule with an isoelectric point of 6.3 and one 13-kD molecule) distinguished P. tenuis from two other nematodes, Dictyocaulus viviparus and Trichinella spiralis. Initial results using serum from experimentally infected elk indicate that this serum recognized a similar profile of P. tenuis antigens when compared with the serum from immunized rabbits. This research has set the foundation for the development of a test for P. tenuis infections in wild and recently domesticated elk and and other ungulates.

Hepatitis B prevalence and associated factors in adults presenting for infection screening in northern Thailand

Developing larvae of Schistosoma mansoni migrate through various tissues en route to the liver and mesenteric veins of their definitive host. Regional (lymph node) and systemic (spleen) blastogenic responses to cercarial, adult and egg antigens were measured in CBA/J mice at various times after exposure to normal or irradiated S. mansoni cercariae. Among the separate lymph node groups studied were those draining the tail, thoracic region, intestines, head and neck, and the pelvis. Blastogenic responses were assayed by a micromethod requiring 10(5) cells in 20 microliter volumes per culture. Up to 5 weeks post-cercarial exposure the pattern of responses in lymphoid tissues of infected mice coincided with the migratory route of the parasites. Following oviposition, cellular reactivity was pronounced in all lymph node groups. The reactivity of mice exposed to irradiated cercariae followed a pattern suggestive of a sustained antigenic stimulus only in the nodes draining the tail and lungs. Splenic (systemic) reactivity was roughly comparable between the two exposure groups. These data show the independence and vast differences in the host regional responses following normal or irradiated cercarial exposure.

Two monoclonal antibodies (MAbs) specific to tobacco budworm, Heliothis virescens (F), and bollworm, Helicoverpa zea (Boddie), eggs were established. These MAbs were tested against all tobacco budworm or bollworm life stages by enzyme-linked immunosobent assay (ELISA). The MAb for tobacco budworm is specific only to budworm egg and adult female antigens, and the MAb for bollworm is specific only to bollworm egg antigen. Eggs of other lepidopterous species tested by ELISA did not react to the species-specific bollworm or budworm MAbs. Eggs from feral insect populations were tested to determine specificity of MAbs, and no cross-reactivity was observed between bollworm and budworm eggs. This highly species-specific characteristic of MAb for bollworm or budworm eggs can be used to distinguish each of these 2 important pests and, thus, help in insecticide selection decisions and insecticide resistance management.

Monoclonal antibodies were generated against transferrin purified from chick embryo extract by fusing spleen cells from BALB/c mice immunized against embryonic transferrin, with myeloma cells. Antibodies produced by the selected hybridoma clones were all type IgG. Twelve clones were selected for secretion of antibodies to the embryo extract-derived transferrin, and three clones were studied extensively. Immunoblotting was used to demonstrate antibody binding to several avian transferrin proteins derived from adult chicken serum, adult chicken peripheral nerves, and ovotransferrin. Screening and detailed epitope analysis were accomplished by solid-phase immunoassay. The results indicated that two clones, 2G9.1 and 2B11.1, recognized the embryonic and egg antigens in preference to the adult proteins. However, a third clone, 6H2.1, recognized the nerve-derived transferrin preferentially to both the embryonic and adult serum antigens. None of the clones recognized the serum-derived transferrin in preference to the other antigens. These results indicate that embryonic epitope(s) are conserved in the nerve- but not the serum-derived transferrin. They also show that the neural antigen has site(s) distinct from the embryonic proteins. No changes in displacement curves were observed after these proteins were digested with neuraminidase, indicating that the epitope differences discovered are not intimately related to sialic acid residues on the various transferrins.

SUMMARY: Hepatitis B virus (HBV) infections are a group of infections that primarily affect the liver and cause inflammatory hepatitis. This group of infections; In Turkey, it develops as acute hepatitis at a rate of 2% to 10%, and 4% to 6% of these cases later develop as chronic hepatitis. 10% of chronic hepatitis cases face the risk of developing hepatocellular carcinoma (HCC) in the future. Various methods are used in the diagnosis of HBV infections. The most commonly used method in diagnosis is the screening of serological indicators (ELISA tests: HBsAg, Anti-HBs, Anti-HBc IgM and Anti-HBc IgG) in serum. Among these indicators, the 'HBsAg' test is the first test used for screening purposes for HBV infection and in the study and interpretation of test results; Evaluation is made by taking into account various factors related to the patient, employee and test procedure. Accuracy and reliability of laboratory test results; It is a very important parameter in terms of both patient safety and control of laboratory test processes. In our case; Based on the 'HBsAg' test result of one patient, our studies and recommendations regarding the false positive HBsAg test results detected in a total of three patients are included. In the root cause analysis studies conducted on the process of 3 patients with unusual 'HBsAg' positivity; Lack of training among the relevant personnel, lack of awareness, failure to carry out device technical service maintenance checks on time, and deficiencies in communication with clinicians came to the fore. As a result of our work on these inappropriate test results; Regular service maintenance and checks of ELISA devices, follow-up and traceability of quality-control studies, and effective communication between the patient's physician and the patient's clinic will prevent the development of situations that may jeopardize patient safety on a laboratory basis.

A total of 35 pigs aged 15 weeks old, and 21 pigs aged 8 weeks old were divided into 7 groups. Groups 1 and 2 were uninfected and challenge control groups, respectively. Groups 3 and 4 were infected weekly with 6 increasing doses of Ascaris suum eggs, and group 4 was additionally treated with pyrantel. Groups 5, 6, and 7 were immunized weekly with the 14, 42, or 97 kDa fractions from adult worms, respectively. Animals of groups 2-7 were challenged with 10000 A. suum eggs 7 days after the last infection/immunization. Serum was sampled weekly and specific IgG1, IgG2, and IgM responses were measured. Pigs of groups 5, 6, and 7 showed high IgG1 and IgG2 responses especially against adult worms antigens, while infected groups had high IgG1 and IgM responses, especially against larva. The IgG1 responses were negatively correlated to the numbers of larvae in the lungs, and positively associated with the liver white spot numbers. There was a positive correlation between IgG2 and the numbers of white spots and lung larvae, while IgM was negatively correlated with these parasitological measures. These findings are discussed and it is suggested that acquired resistance against A. suum larvae is correlated with the induction of IgG1 and IgM, and not with IgG2, and that future vaccination protocols may focus on inducing the Th2 activity.

Resistance produced in mice by exposure to irradiated Schistosoma mansoni cercariae

Changes in the flow and composition of gastric lymph in sheep repeatedly infected with Ostertagia circumcincta

Onchocerciasis is caused by the filarial nematode Onchocerca volvulus and is a major public health problem in West and Central Africa. With only partial and long-term treatment currently available, there is a need to develop a suitable vaccine. We analysed the antibody response to infective L3 larvae because this stage is thought to be associated with host protective immunity. In addition, we have related our findings to the age, gender and current infection intensity of our participants: variables that may significantly influence antibody production. Interestingly, whilst 90% of our study group were seropositive for adult specific immunoglobulin (Ig)E, only 23% produced L3 specific IgE. This is in contrast to IgG4 where seropositivity was comparable at 96% and 92%, respectively. Furthermore, IgG levels were significantly affected by age and the intensity of infection but unaffected by host gender. This finding is independent for the IgG subclass (IgG1, IgG2, IgG3 and IgG4) and its specificity (L3 versus adult antigen). In summary, we show that L3 larvae induce little specific IgE and the antibody response shows a different isotype balance than that against adult antigens. Both host and parasite variables can influence antibody production in this disease.