Toxoplasmosis in Singapore.

Area of Science:

• Medical Microbiology
• Immunology
• Parasitology

Background:

• Toxoplasma gondii infections pose significant health risks.
• Accurate detection of anti-Toxoplasma antibodies is crucial for diagnosis and management.
• Understanding the human immune response, including antibody subclasses and specific antigens, is vital for developing effective diagnostics.

Purpose of the Study:

• To characterize the antibody subclasses (IgG, IgA, IgM) against Toxoplasma gondii.
• To identify key antigenic epitopes recognized by these antibodies.
• To develop a novel IgM capture ELISA for improved detection of Toxoplasma gondii infection.

Main Methods:

• Determination of anti-Toxoplasma gondii antibodies across different IgG subclasses.
• Immunoblot analysis to identify reactive antigens and epitopes.
• Production and characterization of monoclonal antibodies.
• Development and validation of an IgM capture ELISA.

Main Results:

• Immunoglobulin G1 (IgG1) was identified as the dominant subclass in the humoral response to T. gondii.
• Major antigens recognized by IgG and IgM antibodies were of molecular weights 22, 35, and 67 kDa.
• A 22 kDa antigen was consistently detected in positive sera but absent in negative sera.
• IgA antibodies were also detected, with a 14 kDa antigen reacting with all IgA-positive sera.
• A monoclonal antibody (5F3 (A)) was utilized to develop a monoclonal-based IgM capture ELISA targeting 22 kDa and 41 kDa epitopes.

Conclusions:

• The study elucidates the specific IgG subclass profiles and identifies key T. gondii antigens involved in the host immune response.
• The developed monoclonal-based IgM capture ELISA shows promise for accurate detection of T. gondii antibodies.
• Further research into epitope mapping and diagnostic assay development can improve T. gondii diagnostics.