Anti-Ascaris suumimmunoglobulin Y as a novel biotechnological tool for the diagnosis of human ascariasis

Abstract

Human ascariasis is a neglected tropical disease of great relevance to public health and is considered the most frequent helminthiasis in poor regions. Accurately diagnosing this parasite has been challenging due to limitations of current diagnostic methods. Immunoglobulin Y (IgY) technology is a very effective alternative for the production of highly specific and profitable antibodies. This study aimed to produce and apply anti-Ascaris suum IgY antibodies in the immunodiagnosis of human ascariasis. Five immunizations comprising total saline extract from A. suum adult life forms were given at 14-day intervals to Gallus gallus domesticus hens of the Isa Brown line. Eggs and blood samples were collected weekly and fortnightly, respectively, to monitor the production of antibodies. The specificity of antibodies was confirmed by dot-blot, kinetic enzyme-linked immunosorbent assay (ELISA), avidity ELISA, immunoblotting and indirect immunofluorescence antibody tests. The application for disease diagnosis was performed through the detection of immune complexes in human serum samples by sandwich ELISA. Peaks of IgY anti-A. suum production occurred at weeks 6 and 8. IgY showed high avidity levels after the second dose of immunization, ranging from 64% to 93%, with a mean avidity index of 78.30%. Purified IgY recognized 12 bands of proteins from A. suum saline extract. Eggs, the uterine portion and cuticles of A. suum female adult are reactive in immunofluorescence. The detection of immune complexes showed diagnostic values of 80% sensitivity and 90% specificity. In conclusion, specific IgY have been shown to be a potential immunodiagnostic tool with promising future applications in human ascariasis.

IgY antibody and human neurocysticercosis: a novel approach on immunodiagnosis usingTaenia crassicepshydrophobic antigens

“…Lopes et al . (2019), immunizing hens with A. suum antigenic extract, obtained high AI levels of IgY after the second immunization, ranging from 64% (week 2) to 93% (week 10). In this study, we showed high avidity indexes in only 8 weeks of experimentation, ranging from 66.1% (week 2) to 95.08% (week 8).…”

“…Successful application of specific IgY antibodies for antigen recognition by WB and IFAT has been recently performed in other studies with helminths, such as S. venezuelensis (Faria et al ., 2019) and A. suum (Lopes et al ., 2019).…”

“…Nevertheless, detection of circulating immune complexes (CIC) can be used for NCC diagnosis, since it has been successfully applied in helminth diagnosis approaches (Faria et al ., 2019; Lopes et al ., 2019). This method provides clarity to understand changes in the organism before and after disease treatment, since CIC can be present in plasma, and also be found attached to lymphocytes.…”

Use of polyclonal IgY antibodies to detect serum immune complexes in patients with active hookworm infection

“…Data were expressed as the ELISA index (EI) as follows: EI = OD/cut-off of the negative controls (control group − group immunized with PBS) + three standard deviations. To establish the cut-off values for the control group, the OD values from the first 6 weeks were used (Faria et al ., 2019; Lopes et al ., 2019).…”

“…Due to the advantages mentioned above, polyclonal IgY antibodies have been widely used in applications related to parasitic diseases such as toxoplasmosis (Ferreira Júnior et al ., 2012), schistosomiasis (Lei et al ., 2012), trichinellosis (Liu et al ., 2013), strongyloidiasis (Faria et al ., 2019) and ascariasis (Lopes et al ., 2019). In view of this, we developed the first sensitive, specific and noninvasive IgY sandwich-based ELISA to detect immune complexes (ICs) in serum, indicating active hookworm infection.…”