O Neospora caninum é um protozoário apicomplexa com maior implicação em abortamentos em muitos países do mundo. As perdas econômicas determinadas pela neosporose incluem além dos abortamentos também o descarte precoce de vacas, os custos de reposição de novos animais no rebanho, a queda na produção leiteira, bem como na produção da gordura no leite. O diagnóstico imunológico envolve a aquisição de kits diagnósticos existentes no mercado os quais apresentam alto custo. Portanto, o objetivo do presente trabalho foi à produção de hibridomas secretores de anticorpos policlonais com afinidade ao Neospora caninum (cepa Nc-1) para utilização em imunodiagnósticos. Para a produção dos anticorpos usou-se o protozoário sonicado, proveniente da cultura em células VERO, que foi purificado por filtração. Esses taquizoítos foram utilizados na imunização dos camundongos BALB/c, usando-se como adjuvante a saponina, o que permitiu a obtenção de anticorpos policlonais capazes de revelar a fluoresceína na reação da imunofluorescência indireta. A fusão das células esplênicas, provenientes dos camundongos imunizados com as células de mieloma SP2/0 resultou na obtenção de 72,4% de hibridomas secretores de anticorpos anti-Nc-1. Esses hibridomas secretaram anticorpos positivos ao N. caninum e negativos ao Toxoplasma gondii.

The Neospora caninum is a protozoan Apicomplexa with greater involvement in abortions worldwide. The economic losses determined by neosporosis also include abortions besides the early disposal of cows, costs for replacing animals in the herd, drop in milk production as well as milk in fat production. The immunological diagnosis involves purchasing costly diagnostic kits on the market. Therefore, the aim of this study was the production of hybridomas secreting polyclonal antibodies with affinity to Neospora caninum (Nc-1 strain) for immunodiagnostic use. For antibodies production, we used sonicated protozoa from Vero cells in culture, purified by filtration. These tachyzoites were employed for immunization of BALB / c mice using saponin as adjuvant, which allowed obtaining polyclonal antibodies capable of revealing fluorescein reaction in indirect immunofluorescence. The fusion of splenic cells, from the immunized mice with myeloma cells SP2 / 0 resulted in 72.4% hybridomas secreting anti-Nc-1antibodies. These hybridomas secreted antibodies positive to N. caninum and negative to Toxoplasma gondii.

The aim of this work was to evaluate the utility of ELISA-based testing of total IgG (IgGt) antibodies and its subclasses (IgG1, IgG2, IgG3 and IgG4) against soluble (STAg) and recombinant (rSAG1 and rMIC3) antigens of Toxoplasma gondii for diagnosing congenital toxoplasmosis. Sera from 217 newborns initially testing positive for specific IgM in filter paper dried blood spots were tested for specific IgM and IgG by ELFA-VIDAS®. Congenital toxoplasmosis was confirmed in 175 and ruled out in 42 infants. The validity of the ELISA tests was determined using the persistence of IgG antibodies (ELFA-VIDAS® kit) at the end of 12 months, which is considered the reference test for the diagnosis of congenital toxoplasmosis. The frequency of positivity with IgGt against STAg, rSAG1 and rMIC3 was found in 97.2%, 96.3% and 80.2%, respectively, of the newborns with confirmed congenital toxoplasmosis. IgG1 reacted with all three antigens, while IgG3 and IgG4 reacted preferentially with rMIC3. Higher mean values of reactivity (sample optical density/cut-off) were found for all subclasses when using rMIC3. All of the antigens showed high sensitivity and low specificity in detecting anti-T. gondii IgGt and IgG1 and low sensitivity and high specificity in detecting IgG3 and IgG4. In conclusion, the combined detection of IgG antibody subclasses against recombinant toxoplasmic antigens may be useful for the early diagnosis of congenital toxoplasmosis.