Hairy Roots as a Vaccine Production and Delivery System

Abstract

Prevention of infectious diseases by vaccination is often limited because of the lack of safe, effective, and accessible vaccines. Traditional vaccines are expensive and require special conditions for storage, distribution, and administration. Plants have potential for large-scale production of a variety of inexpensive and highly effective recombinant proteins for biomedical and pharmaceutical applications, including subunit vaccines. There are several approaches for the production of vaccine antigens in plants, including transient expression systems based on Agrobacterium delivery of binary vectors or plant viral vectors, stable transgenic plants, and plant cell or tissue cultures. Axenic plant cultures maintained under defined physical and chemical conditions appear to be an attractive production platform when target proteins need to be synthesized in a fully controlled environment. Hairy root cultures meet the criteria for such a system. Hairy root cultures, generated from edible plants and producing target antigens, provide a potential approach for the development of vaccines for oral delivery. With this approach, there are no protein extraction and purification costs and the active biomolecule is protected by the plant cell wall during passage through the upper gastrointestinal tract. This allows for gradual release of antigen at mucosal surfaces in the gut. Lyophilized hairy root cultures expressing vaccine antigens can be stored at ambient temperature for extended periods of time, which should facilitate storage and distribution, ultimately allowing for large populations to be vaccinated.

Production of a tumour‐targeting antibody with a human‐compatible glycosylation profile in N. benthamiana hairy root cultures

“…A major advantage of HRs is the possibility to secrete the recombinant proteins in the culture medium. Previous literature showed that the addition of protein stabilizing agents (PVP and gelatin) and KNO 3 in the medium improved antibody recovery . Moreover, some authors also highlighted the importance of the auxin NAA in increasing rhizosecretion of recombinant proteins .…”

Means to optimize protein expression in transgenic plants

“…Individual culture condition factors in plant cell culture or conventional crop systems which directly or indirectly influence protein production are diverse and previous work has covered them comprehensively [69,70]. A recent review summarizes the existing modeling approaches for plant cultures and the parameters that were covered by the models [71].…”

Current Developments and Future Prospects for Plant-Made Biopharmaceuticals Against Rabies

“…These can be propagated in bioreactors providing a high biosafety system alleviating the concerns related to undesired gene flow that may occur in plants grown in open fields. Moreover, biomass propagation can be optimized and production times reduced [43,44]. An study conducted by Singh et al [45] shows results of engineered tomato hairy roots to achieve the expression of a fusion protein comprising the G protein and the ricin toxin B chain (RGP-RTB).…”