Purification and Characterization of Immunoglobulin Y (IgY) Targeting Surface Antigen 1 (SAG1) of Toxoplasma gondii

Abstract

Toxoplasma gondii (T. gondii) is an obligate intracellular protozoan parasite responsible for toxoplasmosis, a disease with significant health implications for humans and animals. The surface antigen 1 (SAG1) of T. gondii is a major immunodominant protein that facilitates host cell invasion, making it an ideal target for diagnostic and therapeutic interventions. Immunoglobulin Y (IgY), the primary antibody in avian species, offers unique advantages over mammalian IgG, including easier animal care, lower costs, high-yield production, and potential passive immunization. Objectives: This study aimed to induce, purify, and characterize IgY antibodies targeting T. gondii SAG1 from hen egg yolks. Methods: The coding region of the mature portion of T. gondii SAG1 was amplified by PCR, cloned into the pET32a(+) vector for heterologous expression in E. coli. The recombinant SAG1 (rSAG1) was purified by affinity chromatography and used to immunize hens. IgY was extracted from egg yolks using PEG. SDS-PAGE and spectrophotometry were used to evaluate purity and concentration. By ELISA, Western blot, and flow cytometry, the specificity of IgY was assessed against recombinant and endogenous, native, and denatured SAG1. Results: Purified IgY demonstrated strong recognition of both recombinant and native SAG1 in ELISA and Western blot, and against T. gondii tachyzoites by flow cytometry. Conclusions: SAG1-specific IgY was produced in a pure form; it could be helpful in research, diagnosis, and treatment at low costs on a larger production scale, with minimal animal harm.