Progress and challenges in production of recombinant Newcastle disease virus hemagglutinin-neuraminidase subunit vaccine

Abstract

Recombinant Newcastle disease (ND) subunit vaccines are safe, efficacious and compatible with DIVA strategies. Hence, are promising alternatives to conventional live and inactivated vaccines for ND control and prevention. While production of hemagglutinin-neuraminidase (HN)-based ND subunit vaccines have been extensively evaluated at lab-scale, significant barriers impeding successful translation from high-cost, small bench scale production to low-cost mass production remain. This review details current state and challenges in efficacious HN subunit design, advantages and disadvantages of available production routes using different expression hosts together with gaps and solutions regarding quantitative analytical methods used for formulation in dose-efficiency studies. Critical factors influencing HN subunit vaccine immunogenicity such as protein structure, glycosylation and amino acid variations are discussed. Construct design and available expression hosts are then analyzed from viewpoint of yield and quality measured in terms of efficacy. The current deficiency in available quantitative methods for effective dose-efficacy studies is given emphasis, underscoring the importance of robust analytical methods for determination of optimal vaccine dose. The review outlines current state and way forward for the development of HN ND subunit vaccines and other recombinant subunit vaccines for veterinary applications.