Abstract
Toxoplasma gondii is a widespread protozoan parasite that poses significant health risks globally. Current serological tests for diagnosing T. gondii infections are hindered by high costs, cumbersomeness, and the necessity for skills and expertise. This study aimed to identify promising antigens for the development of an immunochromatographic rapid diagnostic test (RDT). Whole-cell antigens were isolated from the virulent RH strain of T. gondii maintained in Swiss albino male mice. After infection, peritoneal fluid was harvested, and tachyzoites were processed to obtain whole cell lysates, which were subjected to SDS-PAGE and Western blot analysis. Five novel antigenic protein bands reactive to anti-Toxoplasma IgG and IgM antibodies were identified on western blot. Subsequent LC-MS/MS analysis revealed 158 proteins. However, only 18 proteins were selected on the basis of high mascot score (> 40) and were investigated further. On BLAST search 10 of these proteins exhibited significant homology (> 90%) with closely related microorganisms hence these were excluded. Out of remaining 8, T. gondii specific glyceraldehyde-3-phosphate dehydrogenase (GAPDH1) and lactate dehydrogenase (LDH1) were found to be reactive to both IgG and IgM on western blot, indicating their potential as reliable biomarkers for T. gondii infection.