Use of viral vectors for vaccine production in plants

Abstract

The small size of plant viral genomes, the ease with which they can be manipulated, and the simplicity of the infection process is making the viral vectors an attractive alternative to the transgenic systems for the expression of foreign proteins in plants. One use of these virus expression systems is for vaccine production. There are two basic types of viral system that have been developed for the production of immunogenic peptides and proteins in plants: epitope presentation and polypeptide expression systems. In this review, we discuss advances made in this field.

Figure 1

Genome organization of viruses used to express heterologous peptides and proteins in plants. Positions where epitopes have been inserted into the coat proteins of the various viruses are shown by black arrows. The positions where foreign proteins (shown hatched) have been inserted into the viral genomes are also indicated. The functions of various virus genes are shown as: CP, coat protein; HC‐Pro, helper component proteinase; Hel, helicase; MP, movement protein; LCP, large coat protein; Pol, RNA‐dependent RNA polymerase; Pro, proteinase; ProC, proteinase cofactor; Reg, regulatory protein; TGB, triple gene block; VPg, virus protein genome‐linked; P1‐Pro, P1‐Proteinase; P3, protein P3; 6K, 6 kDa protein; SCP, small coat protein; VPg‐Pro, VPg‐Proteinase. The asterisk (*) represents a leaky termination codon. CPMV, cowpea mosaic virus; PPV, plum pox virus; PVX, potato virus X; TBSV, tomato bushy stunt virus; TMV, tobacco mosaic virus.