OBTAINING IMMUNODIAGNOSTIC DRUGS FROM TOXOCARA CANIS ANTIGENS FOR SERODIAGNOSIS OF TOXOCARIASIS IN HUMANS

Infekciâ i Immunitet

O. Evdokimova¹  I. Kanina¹  M. Novak¹  A. Novak¹ 

[1] ФГБОУ ВО Рязанский государственный медицинский университет им. ак. И.П. Павлова;

关键词: токсокароз;    иммунодиагностика;    экскреторно-секреторный антиген;    иммуноферментный анализ;    инвазионные яйца;    immunodiagnostics;    excretory secretory antigen;    linked immunosorbent assay;    invasive eggs;    diagnosticum.;   

DOI  :  10.15789/2220-7619-OID-1804

来源: DOAJ

【 摘 要 】

Toxocarosis is a helminthic human invasion that has a wide range of hosts with epizootic distribution. The seropositivity of the population in countries with a temperate climate is about 37%, in regions with tropical climates - up to 92%. Almost all age groups of the population are at risk of invasion by this nematode species. The immunological method currently retains diagnostic significance for toxocariasis, because the reaction of the immune system to helminths is accompanied by the formation of sensitization, and techniques and methods of taking clinical material to identify the migratory form of toxocarosis in humans are  time-consuming and invasive.The purpose of this study is development of  an immunobiological preparation based on excretory-secretory antigens of Toxocara canis larvae for serodiagnosis  of larva migrans syndrome in humans in the reactions of enzyme linked  immunoassay. Antigens were obtained from Toxocara canis larvae by cultivation of  eggs isolated from the uterus of female nematodes in a nutrient medium with glutamine. Purification of the preparation from ballast substances was carried out by centrifugation at 8000 g for 20 minutes followed by filtration through microfiltration membrane with a pore diameter of 0,05-0,15 microns, type MFAS-P-1 (manufactured by CJSC STC Vladipor). Blood serums of student  volunteers from  countries where the incidence of toxocariasis remains high were tested to detect antibodies to toxocars.  Enzyme linked immunoassay with commercial antigens of “Toxocara-IgG-ELISA-BEST” system was used for the selection of seropositive and seronegative sera, that was also used as a control. Diagnostic antigenic preparations with different protein concentrations were prepared for examination of seropositive sera to determine the optimal dose of the antigenic drugs.Results. In an enzyme linked immunoassay with use of a standard test system Toxocara-IgG antibodies were detected in 20 sera (8%) from 250 studied samples, what indicates about antigenic stimulation of the immune system by helminths and possible  disease in past. In the ELISA method with experimental antigen samples, the number of seropositive samples correlated with the protein concentration in antigenic preparations: at a concentration of 1,96 μg / ml   5,2% of positive results were detected, 1,71 μg / ml - 3.2%, 0.33 μg / ml - 0.8% (Pearson's correlation coefficient 0,94). The number of positive sera detected with a commercial antigen in a standard ELISA test system was identical to the number of positive sera detected by an experimental antigen sample  with a protein concentration of 2,49 μg/ml. Thus, the immunodiagnostic preparations obtained by the experimental method based on the excretory-secretory antigens of Toxocara canis are characterized by high sensitivity and can be used to detect Toxocar-IgG antibodies in enzyme-linked immunosorbent assay. The protein concentration of   the antigen preparation of at least 2.49 μg / ml is optimal and correlates whit sensitivity of the commercial antigen of the standard ELISA.

【 授权许可】

Unknown