Development of bovine IgG3-specific assays using a novel recombinant single-domain binding reagent

Area of Science:

• Immunology
• Veterinary Science

Background:

• Cattle possess three IgG antibody subclasses: IgG1, IgG2, and IgG3.
• The immunological function of bovine IgG3 remains largely unknown.
• Existing commercial monoclonal antibodies (mAbs) show limited specificity for bovine IgG3.

Purpose of the Study:

• To evaluate Ankyron™ AZS40101, a novel ankyrin repeat protein, for its ability to bind bovine IgG3.
• To assess the utility of Ankyron™ AZS40101 in detecting IgG3 antibody responses in cattle.

Main Methods:

• Development and characterization of Ankyron™ AZS40101 for bovine IgG3 binding.
• Application of Ankyron™ AZS40101 in ELISA assays for capture and detection.
• Analysis of antigen-specific IgG subclass responses in vaccinated cattle serum.
• Quantification of total IgG1, IgG2, and IgG3 levels in healthy cattle plasma.

Main Results:

• Ankyron™ AZS40101 demonstrated specific binding to bovine IgG3 with minimal cross-reactivity to IgG1 and IgG2.
• The reagent proved effective as both a capture and detection agent in ELISA.
• A low-level antigen-specific IgG3 response was detected alongside IgG1 and IgG2 responses in vaccinated cattle.
• Bovine IgG3 was measurable in healthy cattle plasma at a mean concentration of 0.19 mg/mL, significantly lower than IgG1 and IgG2.

Conclusions:

• Ankyron™ AZS40101 is a valuable new tool for quantifying bovine IgG3.
• This reagent facilitates the study of IgG3-mediated immune responses in cattle.
• Improved measurement of bovine IgG3 responses to infection and vaccination is now possible.