Desenvolvimento de ELISA indireto e teste imunocromatográfico com antígenos recombinantes TES30 e TES120 para o diagnóstico da toxocaríase

Abstract

Toxocariasis is a neglected cosmopolitan disease capable of affecting numerous animals. In humans, the larva can cause damage for months or even years, and depending on its location, such damage may be irreversible. Its difficult diagnosis is one of the main contributing points to its neglected disease character. With a wide range of non-specific signs and symptoms, diagnosis are based on clinical signs, patient history, eosinophilia, and screening for antibodies against total IgE and specific antibodies. The search for specific antibodies is based on the native production of Toxocara canis (TES) excretion and secretion antigens in a laborious, specialized manner, with extensive use of inputs and time. Alternatively, studies have evaluated whether recombinant proteins would have the ability to improve the current disease diagnosis landscape. Thus, this thesis aimed to develop and evaluate an immunoenzymatic and immunochromatographic test with recombinant proteins of T. canis excretion and secretion antigens (rTES-30 and rTES-120) for diagnosis and epidemiological studies of T. canis infection. The recombinant proteins expressed in Escherichia coli showed, in immunoassay tests (ELISA), sensitivities and specificities (above 81%) in experimental model (mouse), human, bovine, ovine and equine. The sensitivity, between 56 and 69%, of the proteins expressed in Pichia pastoris does not favor their use in toxocariasis immunodiagnosis. Moreover, the prototype immunochromatographic test showed diagnostic capacity in humans with sensitivity and specificity, of 74 and 73%, respectively. In conclusion, the present work demonstrated progress in the diagnosis of toxocariasis, presenting a functional model for immunoenzymatic and immunochromatographic diagnosis.