RECOGNITION OF EXCRETED-SECRETED AND SOMATIC ANTIGENS FROM TOXOCARA CANIS LARVAE BY SERA OF PATIENTS WITH DIFFERENT CLINICAL MANIFESTATIONS OF HUMAN TOXOCARIASIS

• DOI: 10.22533/at.ed.813332327034

• Palavras-chave: -

• Keywords: human toxocariasis, antigens, western blot, clinical manifestations

• Abstract:

  Human toxocariasis is one of the most reported zoonotic helminth infections in the world, whose etiological agent is Toxocara canis. Depending on the affected organ, several clinical manifestations can be distinguished: visceral toxocariasis, pulmonary toxocariasis, cutaneous toxocariasis, ocular toxocariasis or asymptomatic toxocariasis, among others. This makes the diagnosis very difficult. The purpose of this study is to contribute to the knowledge of human toxocariasis, especially in the serodiagnosis, analysing the recognition of specific antigens by sera from patients with different clinical manifestations of the disease. Western blot technique (WB) was used to analyse larval somatic antigens (LS) and excreted-secreted (ES) antigens of larvae of T. canis, recognized by IgA and IgG class of immunoglobulins. Thus, four detection systems were used: LS/IgG, LS/IgA, ES/IgG, and ES/IgA.

  The antigen detection was greater with LS antigens than ES antigens using  Western blot.  The highest sensitivity (81%) was found with the LS /IgG  system, and the lowest (19%) with the ES/IgA one;  in relation to sera detected by ELISA. Very interesting, with almost all antigen/antibody systems were detected different sets of antigens; depending of kind of toxocariasis were the sera came from. Even more, in several cases a unique antigen, was found only with one kind of toxocariasis sera.  However, it is necessary further studies in order to confirm these results with a more high number of patients presenting these four form of toxocariasis.  The greater percentage of detection (78%) with a specific antigen of 40 kDa, was obtained using ES / IgA, in asyntomatic toxocariasis.  This result is relevant since this antigen could guide diagnosis in the acute phase of the disease.

  However, the finding of specific antigens to some of the clinical manifestations opens the possibility of optimizing techniques using purified antigens to maximize their detection, in order to improve the diagnosis of the different toxocariasis forms.