Monoclonal antibodies (MAb) against Taenia crassiceps and Taenia solium cysticerci were produced and showed cross-reactivity with a 14-kDa protein from T. solium and with 18-and 14-kDa proteins from T. crassiceps. These MAbs and antibodies from cerebrospinal fluid (CSF) as well as serum samples from patients with neurocysticercosis (NC) reacted with 18-and 14-kDa T. crassiceps proteins purified by immunoaffinity chromatography using a Sepharose column coupled with MAbs (anti-excretory/secretory or anti-vesicular fluid antigens). Immunoaffinity-purified 18-and 14-kDa proteins were used in the design of a diagnostic enzymelinked immunosorbent assay (ELISA) to detect antibodies in 23 CSF and 20 serum samples from patients with NC, showing 100% sensitivity. The test specificity was determined using 42 noninflammatory CSF samples and 70 inflammatory CSF samples from patients with other neurological disorders (OND), showing 100% and 99.1% (confidence interval, 97.3% to 100%) specificity, respectively. A false-positive CSF sample result in the OND group was from a human immunodeficiency virus-positive patient with meningoencephalitis. By using serum samples from 194 healthy individuals, the specificity was 100%. Analysis of an additional 16 serum samples from individuals with other parasitic diseases (13 with intestinal parasitosis and 3 with schistosomiasis) showed negative results. Three (10%) serum samples from patients with hydatidosis were positive in our ELISA and in ELISA with T. solium cysticerci antigens. Two of them were also positive by immunoblotting. The use of 18-and 14-kDa T. crassiceps immunoaffinity-purified proteins for detection of anti-cysticercus antibodies in CSF and/or serum samples using an ELISA system showed a good performance and high specificity for serum samples, dispensing with the use of confirmatory tests, such as immunoblotting, for checking specificity.

In order to evaluate the taeniosis-cysticercosis complex in a population of a peasants ' settlement, located at Teodoro Sampaio, state of São Paulo, Brazil (longitude 52°36'12", latitude 22°17'12") The taeniosis-cysticercosis complex is an important cause of morbidity and mortality, widespread not only in most underdeveloped countries, but also in industrialized ones (Raether & Hanel 2003). There is strong evidence supporting the high prevalence of Taenia infection in humans from resource-poor areas, especially in rural areas with deficient sanitation, low hygienic standards, and unusual customs, such as consumption of raw pork (Phiri et al. 2003).Taenia solium and Taenia saginata are two taenids of great economic and medical importance, causing bovine and porcine cysticercosis and taeniosis in humans. The encysted larva, known as cysticercus from T. saginata and T. solium are found in cattle and swine, respectively, and the adult tapeworm of T. saginata and T. solium are found in man. The cycle is completed when eggs in proglottids shed from the human tapeworm are disseminated to the environment through feces, followed by the ingestion by cattle or swine, and then the viable cysts are eaten by man in undercooked beef (Lees et al. 2002). People are also infected by ingestion of T. solium or T. saginata eggs by contact with carriers or contaminated foods. Cysticercosis is an infection caused by cysticercus, the larval stage of Cestoda Family Taeniidae. Neurocysticercosis (NC), the nervous-system form of cysticercosis is caused by larvae of tapeworm T. solium (Carpio 2002).In Brazil, several previous studies have shown that NC in humans is an important public-health problem; although, very few reports on the prevalence and distribution of porcine cysticercosis have been published (Sakai et al. 2001). In the state of São Paulo, the frequency of anti-T. solium cysticercus antibodies in humans was determined in few counties (Vaz et al. 1990, Bragazza et al. 2002. Nonetheless, studies about the prevalence of T. saginata infection in humans or the presence of T. saginata cysticercus in cattle are scarce (Ungar & Germano 1992). Dias et al. (1991) found in 311 samples of stools of humans living in the state of São Paulo an occurrence of 0.5% in Taenia sp. eggs; of which 273 were identified as T. saginata proglottidis.The ELISA screening test is commonly used for the serological diagnosis of cysticercosis, although it crossreacts with cestoda parasites such as Hymenolepis nana and Echinococcus granulosos (Garcia et al. 2003, Ishida et al. 2003. Low-molecular-weight glycoproteins obtained from T. solium by affinity chromatography, considerably improved the specificity of ELISA screening tests, but a large amount of antigens is required (Tsang et al. 1989). Recently, it has successfully been reported the use of low-molecular-weight peptides obtained from the vesicular fluid of T. crassiceps antigens (Tcra-VF) and T. crassiceps cysticercus glycoproteins (Tcra-GP and Tcra(18-14)-GP in ELISA and immunoblot assays , Ishida e...

Glycoproteins from the total vesicular fluid of Taenia crassiceps (VF-Tc) were prepared using three different purification methods, consisting of ConA-lectin affinity chromatography (ConA-Tc), preparative electrophoresis (SDS-PAGE) (14 gp-Tc), and monoclonal antibody immunoaffinity chromatography (18/14-Tc). The complex composition represented by the VF-Tc and ConA-Tc antigens revealed peptides ranging from 101- to 14-kDa and from 92- to 12-kDa, respectively. Immunoblotting using lectins confirmed glucose/mannose (glc/man) residues in the 18- and 14-kDa peptides, which are considered specific and immunodominant for the diagnosis of cysticercosis, and indicated that these fractions are glycoproteins. Serum antibodies from a patient with neurocysticercosis that reacted to the 14 gp band from T. crassiceps (Tc) were eluted from immunoblotting membranes and showed reactivity to 14 gp from Taenia solium. In order to determine the similar peptide sequence, the N-terminal amino acid was determined and analyzed with sequences available in public databases. This sequence revealed partial homology between T. crassiceps and T. solium peptides. In addition, mass spectrometry along with theoretical M(r) and pI of the 14 gp-Tc point suggested a close relationship to some peptides of a 150-kDa protein complex of the T. solium previously described. The identification of these common immunogenic sites will contribute to future efforts to develop recombinant antigens and synthetic peptides for immunological assays.

Background: The goal of this study was to estimate the seroprevalence of Toxocara spp., Toxoplasma gondii, and Taenia solium metacestode infection and determine some of the associated risk factors for people living in the Dona Carmen settlement, Pontal of Paranapanema, Sã o Paulo, Brazil. Methods: Serum samples from 194 subjects were tested and participants answered a questionnaire. An enzyme-linked immunosorbent assay (ELISA) system based on Toxocara spp. excretory-secretory antigens obtained from the cultured second-stage larvae of Toxocara canis or vesicular fluid (VF) antigen from Taenia crassiceps metacestode was used to detect anti-Toxocara spp. IgG and IgE and anti-T. solium metacestode, respectively. For cysticercosis, the reactive ELISA samples were assayed by Western blotting using 18 kDa and 14 kDa proteins purified from VF. For T. gondii-specific IgG and IgM antibodies, anti-SAG-1, GRA-1, and GRA-7 epitope specificity was determined by ELISA. Results: Toxoplasma gondii IgG antibodies were found in 102/194 individuals (52.6%) with increased infections in females (P 5 0.02) and those with #US$300 monthly income (P 5 0.01). Positive IgM antibodies were detected in 21/194 individuals (10.8%). Antibodies specific to Toxocara spp. were found in 28/194 subjects (14.4%). All the individuals with Toxocara spp. also had T. gondii-specific IgG antibodies. Taenia solium metacestode antibodies were detected in 11 subjects (5.7%), but none were reactive based on Western blotting. Conclusion: In spite of environmental, educational, and socioeconomic factors favoring parasite infection, the seropositivity rates of T. gondii, Toxocara spp., and T. solium metacestode-specific IgG antibodies are similar to the rates found in studies conducted in different populations in Brazil.