E. Yu. Sarkisyan¹, H. A. Haroutyunyan², Ye. G. Sargisova¹*

¹H. Buniatian Institute of Biochemistry of National Academy of Sciences of Armenia, Yerevan;
²Laboratory of Biochemical and Biophysical Investigations,
Scientific-Research Centre, Yerevan State Medical University after Mkhitar Heratsi, Armenia;
*e-mail: lizasar2001@yahoo.com

Received: 22 April 2025; Revised: 09 July 2025;
Accepted: September 2025; Available on-line: 2025

Purification of human plasma adenosine deaminase 2 (ADA2) is challenging due to its low physiological concentration and co-purification of human immunoglobulin G (IgG), which has similar physicochemical properties. This study describes a novel approach exploiting avian immune tolerance to human IgG to selectively produce antibodies against native and active human ADA2. Chickens were rendered tolerant to human IgG, enabling subsequent immunization with a preparation containing both ADA2 and human IgG. This strategy successfully elicited a specific immune response, yielding antibodies exclusively to ADA2. These anti-ADA2 antibodies (IgY), purified from egg yolks, were subsequently employed in an affinity column. This immunopurification method allowed the isolation of an electrophoretically homogeneous preparation of human ADA2. This study demonstrates the utility of inducing immune tolerance to human IgG in chickens.