Cysticercal Antigens Research Articles

Taenia crassiceps cysticercosis: immune response in susceptible and resistant BALB/c mouse substrains.

Taenia crassiceps can naturally and experimentally infect rodents in which they reproduce by budding. Differences in the susceptibility to T. crassiceps cysticercosis were found between two BALB/c substrains: BALB/cAnN (susceptible) and BALB/cJ (resistant). In chimeric mice, resistance was transferred to susceptible mice with bone marrow cells from the resistant mice, which argues in favor of an immune mediation of the resistant phenotype. To further explore the immune response that could underlie these differences in susceptibility, the specific cellular immune response elicited by the parasite was explored in both substrains. An increased proliferative response and IL-2 levels were induced by cysticercal antigens only in splenocytes from resistant mice. A decrease in the percentage of CD4(+) (11.1%), CD8(+) (17.5%) was found in splenocytes from susceptible BALB/cAnN mice. A study of the TCRV beta repertoire revealed a significant decrease in V beta 2 in both CD4(+) and CD8(+) splenocytes only in the susceptible BALB/cAnN strain.

CD4+ and CD19+ splenocytes undergo apoptosis during an experimental murine infection with Taenia crassiceps.

The Taenia crassiceps cysticercus is a cestode that naturally and experimentally infects rodents in which it reproduces by budding. In the laboratory, a persistent cellular immunosuppression with a concomitant increasing load of parasites has been observed in experimentally infected BALB/cAnN mice. In this study, enhanced apoptosis was found in spleen cells from 30-day infected mice with a typical "ladder-patterned" DNA fragmentation and an increase in phosphatidylserine expression. A characteristic poly-(ADP-ribose) polymerase cleavage indicates that this cell death is caspase-mediated. Apoptosis was detected in the CD4(+) and CD19(+) splenocytes of infected mice after in vitro stimulation with cysticercal antigens. Considering previous results on the crucial role that CD4(+) T cells play in controlling the extent of infection, apoptosis in this T-lymphocyte subpopulation induced by T. crassiceps cysticerci could be responsible for the immunosuppression that underlies parasite success.

Multiple cysticercus nodules in skin and brain in a Balinese woman: A case report

A case of multiple subcutaneous and cerebral cysticercosis in a 33-year-old Balinese female, is reported. The patient suffered from seizures since adolescence, which was not treated. Since three years before admission she started developing multiple nodules in the skin, starting from her forehead and since a year ago also in other parts of the head and body such as shoulders, chest and back. Serum sample tested against cysticercus antigen by immunoblot assay against antigen of Taenia solium was positive. The copro-antigen test was also positive, indicating the presence of the adult worm in the intestines. The patient was treated with praziquantel for the adult T. solium infection and thereafter with albendazole for the larval stages, which resulted in obvious reduction of the cerebral cysts and most of the subcutaneous nodules disappeared. However the adult worm was not recovered in the 24 hours stool specimen and after one year the immunoblot test was still positive. (Med J Indones 2002; 11: 169-73) Keywords: cysticercosis, Taenia solium, praziquantel, albendazole

Assessment of antibody responses to antigens of Mycobacterium tuberculosis and Cysticercus cellulosae in cerebrospinal fluid of chronic meningitis patients for definitive diagnosis as TBM/NCC by passive hemagglutination and immunoblot assays

Tanned sheep erythrocytes stabilized with pyruvic aldehyde and glutaraldehyde, called double-aldehyde-stabilized cells, were used to standardize passive hemagglutination assay (PHA) for detection of antibody responses to sonicate extract of Mycobacterium tuberculosis and Cysticercus cellulosae soluble antigens. PHA was performed in the following groups of cerebrospinal fluid (CSF) samples: group I – chronic infections of the central nervous system with the possible diagnosis of tuberculous meningitis (TBM), tuberculoma and neurocysticercosis (NCC) ( n=88), and group II – controls which included (a) non-infectious non-neurological conditions ( n=30), (b) infectious neurological conditions ( n=21) and (c) non-infectious neurological conditions ( n=133). PHA could detect anti-mycobacterial antibodies at the sensitivity level of 80.76% with a specificity of 92.4% and anti-cysticercal antibodies with a sensitivity of 100% and specificity of 92.94%. However, in 6.33% (i.e. 14/221) of group I and group II (c) CSFs both anti-mycobacterial and anti-cysticercal antibodies were detected. Immunoblot analysis of CSFs derived from TBM patients reacted predominantly to 120-kDa, 96-kDa, 65-kDa, 38-kDa, 26-kDa, 23-kDa, 19-kDa and 12–14-kDa and 4–6-kDa antigens of M. tuberculosis sonicate extract (MTSE), whilst CSFs of proven NCC reacted to >110-kDa, 96-kDa, 80-kDa, 66–68-kDa, 52-kDa and 26–28-kDa antigens of porcine whole cyst sonicate extract (PCSE). On immunoblot analysis, some of the CSFs of TBM patients were PHA positive for both MTSE and PCSE showed antibody reactivity to 70-kDa and 10-kDa antigens of C. cellulosae. Similarly CSF antibody of some Guillain Barre syndrome and myeloradiculopathy patients reacted with cysticercal antigens. But per se no cross-reactivity between MTSE and anti-cysticercal antibodies and vice-versa were observed. However, findings of this study should alert laboratory personnel especially in endemic areas to be extra careful in interpretation of antibody detection results.

Use of Taenia crassiceps cysticercus antigen preparations for detection of antibodies in cerebrospinal fluid samples from patients with neurocysticercosis (Taenia solium).

Antigen extracts obtained from the vesicular fluid of Taenia crassiceps cysticerci and from fractions purified by affinity chromatography with the lectin concanavalin A and the glycoprotein antigen separated by electrophoresis were used for the detection of Taenia solium anticysticercus antibodies. The sensitivity and specificity obtained for all antigens were 100% in enzyme-linked immunosorbent assay with good reproducibility. Using immunoblotting of the three antigens, low-molecular-mass peptides (18 and 14 kDa) were characterized only in cerebrospinal fluid samples from patients with neurocysticercosis. The results confirm that antigen fractions purified from T. crassiceps cisticerci are important sources of specific peptides and proved to be efficient in detecting anti-T. solium antibodies.

Cellular immune responses in human neurocysticercosis.

Studies on the role of cell-mediated immune responses in human neurocysticercosis (NCC) are lacking. Various cell-mediated immune responses such as lymphocyte subpopulation, lymphocyte transformation to cysticercus antigens and cytokine profile were carried out in NCC patients. Lymphocyte transformation assays using larval antigens showed significantly higher (3)H-thymidine uptake. Immunophenotyping analysis showed an insignificant increase in B cells and a decrease in total T cells. However, there was a significant decrease (P < 0.05) in CD8+ T cells whereas there was no change in other cells like CD4+, HLA-DR+ and CD16+/CD56+. Cytokine profile revealed significantly higher (P < 0.01) production of Th1 cytokines (gamma-IFN and IL-2) using cysticercal antigens as stimulants for peripheral blood mononuclear cells, while there was no difference in IL-4 levels between NCC patients and healthy controls. The cytokine profile indicated the involvement of Th-1-like responses in NCC patients.

Cysticercosis: towards the design of a diagnostic kit based on synthetic peptides

Cysticercosis caused by Taenia solium is a very common disease in developing countries that seriously affects human health. Diagnosis can only be confirmed with the aid of computerized tomography or nuclear magnetic resonance (NMR) creating obvious difficulties for epidemiological studies. Reliable immunoassays employing cerebrospinal fluid (CSF) have been developed, based on the use of cysticercal antigens. However, the reliance on parasite material is restrictive. Herein, we report the advances in the design of a diagnostic kit based on immunodominant synthetic peptides, targeting four candidate epitopes KETc1, KETc12, 410 and 413 which were identified from three different clones (KETc1, 12 and 4) selected from a cDNA library of Taenia crassiceps. CSF antibodies against T. solium cysticercal antigens (TCA) as well as the four peptides were determined by enzyme-linked immunoabsorbent assays (ELISA) using two panels of CSF from patients with confirmed neurocysticercosis and other neurological diseases. In the first CSF panel which included patients with high level of antibodies against TCA, KETc12 exhibited almost the same sensitivity (87.5%) as TCA (93.7%) and 100% specificity. In the second panel of 110 CSF collected at random, two peptides (KETc1 and KETc12) exhibited sensitivities of 40 and 36%, respectively, and were 100% specific.

Immunotherapy for porcine cysticercosis: implications for prevention of human disease. Cysticercosis Working Group in Peru.

Taenia solium cysticercosis is an important cause of human disease in many developing countries. Porcine cysticercosis is a vital link in the transmission of this disease and impairs meat production. A treatment for porcine cysticercosis may be an effective way of preventing human disease that would also benefit pig farmers, facilitating control programs in disease-endemic regions. Previous research suggests that reinfection with cysticercosis or immunotherapy with cysticercal antigens may cause degeneration of cysticerci, potentially curing porcine cysticercosis. Therefore, a blinded, randomized, controlled study to assess the efficacy and safety of immunotherapy in 28 naturally parasitized pigs was performed. Four groups of pigs with similar weights were inoculated twice with membrane-enriched cysticercal antigens (MA), saline, aqueous-soluble crude cysticercal antigens (AA) in adjuvant (Freund's complete then incomplete), or adjuvant alone. Immunotherapy was well tolerated but had no consistent effect on the macroscopic appearance of cysticerci or eosinophil count. Histopathologic findings were variable, with both severe and minimal inflammatory reactions seen in adjacent cysticerci in all pigs. Nine (64%) of 14 pigs given immunotherapy developed new antibody bands on electroimmunotransfer blot compared with one (7%) of 14 control pigs (P < 0.01). Treatment with AA in adjuvant caused a significant increase in the proportion of cysticerci that failed to evaginate and were, therefore, not viable for infecting humans (34% for pigs given AA in adjuvant compared with 10% for adjuvant alone; P < 0.04). Although immunotherapy caused a statistically significant decrease in the viability of cysticerci, this immunologic reaction was not great enough to prevent human disease.

Evaluation of the efficacy of albendazole against the larvae of Taenia solium in experimentally infected pigs, and kinetics of the immune response

Cysticercosis, a disease of economic and public health importance, is caused by Cysticercus cellulosae, the metacestode stage of Taenia solium. Experimental induction of cysticercosis was achieved in young pigs by feeding an optimum dose of 20,000 T. solium (Indian strain) eggs after immunosuppression, to assess the effect of albendazole and development of the immune response to cysticercus antigens before and after treatment. Histopathological studies revealed the presence of cysticerci in liver, lungs and muscles. Treatment with albendazole at 15 mg kg −1 body weight daily for 30 days starting from day 0 or 15 days post-infection resulted in 100% cure rates. Increases in antibody titre to crude soluble extract and a Sephadex G-200 purified antigenic fraction of Cysticercus cellulosae were found on days 25, 40 and 55 post-infection in untreated pigs and those in which treatment started on day 15 post-infection, whereas no increase in antibody response was observed in pigs in which treatment started on day 0.

Depressed T-cell proliferation associated with susceptibility to experimental Taenia crassiceps infection

Peritoneal infection with Taenia crassiceps cysticerci of naturally resistant (C57BL/10J and C57BL/6J) and susceptible (BALB/cAnN) mice induces a cellular immune depression. T-cell proliferation in response to concanavalin A (ConA) or anti-CD3 was significantly depressed in infected mice of all strains tested. However, in resistant mice, the diminished response to ConA was transient and animals recovered normal responsiveness at day 40, whereas susceptible mice remained suppressed throughout the 40 days of the experiment. In contrast, the proliferative response to anti-CD3 was lower in infected mice than in noninfected controls regardless of differences in natural susceptibility of the strains. Intraperitoneal injection of mice with a parasite extract also induced a depression of the response to ConA, although not as strong as that produced by the parasite itself. This depression is not due to direct effects by parasite antigens over host lymphocytes, as proliferation is not affected by the presence of cysticercal antigens added in vitro. Diminished interleukin-2 production during the parasitosis accounts at least in part for the diminished responses to ConA. A primary infection favors parasite establishment after a second challenge, pointing to the relevance of the immunodepression in generating a host environment favorable to the parasite.

Analysis of antigenic variation in Cysticercus cellulosae and partially purified cysticercal antigens by crossed immunoelectrophoresis

Rabbit anticysticercal polyclonal antibodies were used to analyse soluble antigens for a whole cyst sonicate of Cysticercus cellulosae derived from geographically different infected pigs, human tissue and partially purified cysticercal antigens by crossed immunoelectrophoresis (CIE). There were qualitative and quantitative differences in the antigens for porcine and human cyst sonicates. On analysis by CIE with intermediate gel technique (CIE-i.g.), human cyst sonicate (HCS) lacked four immunodominant parasite antigens (15, 16, 17 and 18) found in the porcine cyst sonicate (PCS). An immunoaffinity (·) purified parasitic antigen (IAPP) and antigen B, respectively contained 11 and five antigens. Five antigenic components of antigen B were immunochemically identical to 2, 3, 4, 5 and 16 antigens of PCS 8 88 . Further, the antigen B was found to be derived chiefly from scolex and vesicular fluid.

Cross reactions in the immunodiagnosis of schistosomiasis and cysticercosis by a cerebrospinal fluid enzyme-linked immunosorbent assay

Cerebrospinal fluid was collected from 3 groups of patients (suspected cysticercosis patients, myelopathy patients, and neurological patients) and assayed for antibodies to Cysticercus cellulosae and schistosome soluble egg antigen. In the myelopathy and neurological patients there was a significant correlation ( P < 0·05) between seropositivity for the two diseases. Samples which were positive in both assays were tested by inhibition assay with the heterologous antigen to determine the specificity of the reaction. In one of 5 cases the reaction to cysticercus antigen was completely inhibited by addition of schistosome soluble egg antigen. In the reverse assay there was minimal inhibition by cysticercus antigen.

Specific antibodies in serum of patients with hydatidosis recognised by immunoblotting

Hydatid fluids from sheep, goat, pig and man, after resolution by sodium dodecyl sulphate-polyacrylamide gel electrophoresis under reducing conditions, revealed at least 15 discrete polypeptide bands of 8-116 Kda. By ELISA, sera from all 20 cases of hydatidosis showed anti-hydatid antibody, but so did 11 (73%) of 15 sera samples from cysticercosis patients, eight (67%) of 12 sera from patients with other parasitic infections (amoebic liver abscess or hymenolepiasis) and one (4%) of 25 sera from healthy controls. Antibody to cysticercus antigen was found in 14 (93%) of 15 sera from cysticercosis patients, 17 (85%) of 20 sera from hydatid patients, six (50%) of 12 sera from patients with other parasitic infections and one (4%) of 25 sera from healthy controls. Sera from 17 (85%) of 20 hydatid patients, 11 (73%) of 15 cysticercosis patients and five (42%) of 12 patients with other parasitic infections had antibodies to both hydatid and cysticercus antigens. Sera from 20 surgically confirmed cases of hydatidosis reacted with 12 polypeptides of 8-116 Kda in Western immunoblot with hydatid antigens. Polypeptides of 16, 24, 38, 45 and 58 Kda were recognised by all hydatidosis sera but also by many sera from patients with other infections. However, polypeptides of 8 and 116 Kda were recognised by all hydatidosis sera but not by any sera from patients with cysticercosis, other parasitic infections or viral hepatitis, or from healthy controls. Thus, recognition of 8- and 116-Kda hydatid antigens by a patient's serum appears to be a specific test confirming a clinical diagnosis in an individual case of hydatidosis.

Comparative evaluation of cysticercal antigens and immunoassays in the diagnosis of neurocysticercosis

Enzyme linked immunosorbent assay (ELISA), dot immunobinding assay (DIA) and passive haemagglutination assay (PHA) were evaluated for the detection of anticysticercal antibodies in cerebrospinal fluids (CSF) from neurocysticercosis (NCC) patients. Results from the three tests were similar. Higher titres of antibodies were observed to the antigens in porcine whole-cyst sonicate than to those in vesicular fluid or scolex or membrane sonicates. Affinity purified parasitic antigens showed a higher degree of specificity and sensitivity in PHA than in ELISA or DIA. Western blot analyses with cyst antigens showed that CSF antibodies from confirmed NCC patients consistently recognized a protein in the region of 64-68 kDa. Other proteins, of 110, 94-97, 80, 72-75, 52, 45, 26-28 and 16-18 kDa, showed heterogenous reactivity, whereas the partially purified antigen of 64-68 kDa showed a high degree of sensitivity and specificity.

Detection and characterisation of circulating cysticercal antigens in human cerebrospinal fluid

With biotin labelled and unlabelled immunoglobulin fraction of anticysticercal antibodies raised in rabbits, tandem-enzyme linked immunosorbent assay (T-ELISA), capture-dot immunobinding assay (C-DIA) and reverse passive haemagglutination (RPHA) tests were developed for the detection of cysticercal antigens. The sensitivity levels were respectively, 9 ng ml −1, 2 ng ml −1 and 45 ng ml −1. All three methods were of equal specificity as none of the antigens of Mycobacterium tuberculosis, Japanese encephalitis virus and Echinococcus granulosus reacted with anticysticercal IgG. Cysticercal antigens were detected in the cerebrospinal fluid (CSF) of confirmed neurocysticercosis at sensitivity levels of 91·6% by T-ELISA, 83·33% by C-DIA and 75% by RPHA and specificity levels of >93%. Western analysis of these antigens in CSF showed mainly antigens of 64–68 kDa and 24–28 kDA. By crossed immunoelectrophoresis (CIE) with an intermediate gel technique, five circulating antigens were found to be released from scolex and fluid.

Sub acute and chronic meningitis in children—An immunological study of cerebrospinal fluid

Cerebrospinal fluid (CSF) from 274 cases of subacute to chronic meningitis in age groups from 3 months to 12 years were analysed for the presence of antibody response to mycobacterial and cysticercal antigens by enzyme linked immunosorbent assay (ELISA). Simultaneously other correlative parameters such as CSF cell cytology by cytospin studies, mycobacterial antigens of Lipoarabinomannan (LAM) type (a polysaccharide antigen) by reverse passive haemagglutination assay (RPHA) CSF C-reactive protein (CRP) by latex agglutination and microbial cultures for mycobacterium tuberculosis and fungi were carried out. Antimycobacterial antibody was present in 35.4% of the cases. In 57.66% of the cases there was no demonstrable immune response to either mycobacterial or cysticercal antigens. However, it was interesting to note that 5.47% of the cases revealed the presence of anticysticercal antibody in the CSF. The mycobacterial antigen (LAM polysaccharide antigen) was found in 72.6% of the cases. There was no evidence of carcinomatous or cryptococcal meningitis. This study stresses the role of multimodal diagnostic tests on CSF for investigating cases of chronic and subacute meningitis irrespective of leading clues such as tuberculosis.

Immunodiagnosis of human cysticercosis (Taenia solium) with antigens purified by monoclonal antibodies.

Monoclonal antibodies were generated from mice immunized with scolex protein antigen of Cysticercus cellulosae. Three monoclonal antibodies specific for cysticercal antigens, which did not show any cross-reactivity with Taenia solium or Taenia saginata antigens, were selected. Each monoclonal antibody coupled to Sepharose could purify one antigen, which appeared as a single band on polyacrylamide gel electrophoresis. When antigens purified by monoclonal antibodies were used to detect antibody in serum samples taken from patients with cysticercosis, taeniasis, and other parasitic infections in an enzyme-linked immunosorbent assay, cross-reactivity was observed until a serum dilution of 1:128 was reached. Since serum samples from unexposed subjects showed positive reactions until a dilution of 1:64 was reached, we chose a discriminative dilution (1:128) above which no cross-reaction was observed. The percent positive serum samples from cysticercosis patients was 100% by the enzyme-linked immunosorbent assay with any of the antigens purified by monoclonal antibodies.

ELISA in the diagnosis of neurocysticercosis.

IgM antibodies against cysticercus antigens were measured by enzyme-linked immunosorbent assay (ELISA) in 133 serum and 126 cerebrospinal fluid (CSF) samples from patients with active neurocysticercosis (NCC), in 61 serum and 32 CSF samples from patients with inactive NCC, and in 556 serum and 449 CSF samples from patients with other neurological disorders. For diagnosis of active NCC the test showed 50% sensitivity with 70% specificity in serum and 87% sensitivity with 95% specificity in CSF. We concluded that the use of the ELISA with serum is not reliable for diagnosis of NCC and therefore cannot be used routinely for the detection of cases or epidemiological studies. Conversely, ELISA used with CSF is highly dependable for detecting all forms of active NCC. The possible explanations for the discrepancy between serum and CSF results are discussed.

Host-parasite relationship in cysticercosis: Immunologic study in different compartments of the host

Cysticerci parasitize several mammalian species, including man, in which the parasitic disease shows unique characteristics since cysticerci are established mainly in immunologically privileged sites and can survive for many years. The study of the human immune response to cysticerci is helpful in diagnosis and could perhaps also aid in preventing or curing the disease. Anti-cysticercus IgG can be detected in serum and cerebrospinal fluid (CSF) of almost all patients with neurocysticercosis, by the enzyme-linked immunosorbent assay (ELISA); antibodies of the other classes are found less frequently. Antibodies react with up to eight Taenia solium cysticercus antigens, mainly with antigen B. This antigen has an affinity for collagen and is not commonly found in the CSF. It could therefore be participating in vasculitic processes spotted in the brain of neurocysticercotic patients. Immunoglobulins are also identified on the surface of the parasites: IgG is detected on parasites obtained from various tissues; IgM, IgA and IgE mostly on extracerebral cysticerci. We discuss the possibility of extraneural cysticerci being destroyed by the immune response of the host whereas natural aging may cause brain cysticerci death.

Antigen-Antibody Analyses in Neurocysticercosis

In this report we show that there are 37 polypeptides of larval Taenia solium which react with antibodies from humans with neurocysticercosis. Six of these 37 polypeptides are recognized by antibodies present in the sera of both patients and control individuals. Thus, a minimum of 31 antigens are specific for cysticerci. We describe herein the antigens more frequently recognized by the patients, and the immunoglobulin classes favored in antibody production against each of the cysticercal antigens. It was found that there are 10 major polypeptides with molecular weights of 200,000, 64,000, 62,000-61,000, 53,000, 45,000, 41,000, 36,000-35,000, 30,000 and 16,000 daltons. About 65% of the larval components found to be antigenic are glycoproteins with oligosaccharide chains containing N-acetyl-D-glycosamine and alpha-D-galactose. These results suggest that the sugar moieties of glycoproteins may play a role in the antigenicity of larval T. solium. Based on these observations polypeptides with molecular weights of 64,000, 53,000, and 32,000-30,000 daltons are probably the best choice as sources of antigen to develop an optimal immunological test for the serological diagnosis of neurocysticercosis.