Foreign gene expression in Corynebacterium pseudotuberculosis: developmentof a live vaccine vector

A defined phospholipase D mutant of Corynebacterium pseudotuberculosis, des ignated Terminus, was used as a live vector to express and deliver a range of candidate vaccine antigens to sheep. Expression levels of the foreign ge nes in Terminus were evaluated when directed from a number of different pro moters, both constitutively expressed and inducible, as fusions with expres sed genes including a signal sequence, and from chromosomal and episomal lo ci. In general expression levels were low and it appeared that some of the recombinant proteins were tolerated by C. pseudotuberculosis Terminus bette r than others. Gene expression was however sufficiently high for three of t he genes to elicit antibody responses specific to the recombinant protein f ollowing a single dose of the live Terminus vector vaccine. This work sugge sts that C. pseudotuberculosis Terminus has potential for development as a live veterinary vaccine vector. (C) 1999 Elsevier Science Ltd. All rights r eserved.