K.K.D. and P.S. sincerely acknowledge the support and facility provided by the M.D. University, Rohtak, Haryana. P.S. acknowledges the infrastructural support from Department of Science and Technology, Govt. of India through FIST grant (Grant No. 1196 SR/FST/LS-I/2017/4).Plants as bioreactors have been widely used to express efficient vaccine antigens against viral, bacterial and protozoan infections. To date, many different plant-based expression systems have been analyzed, with a growing preference for transient expression systems. Antibody expression in diverse plant species for therapeutic applications is well known, and this review provides an overview of various aspects of plant-based biopharmaceutical production. Here, we highlight c...