Abstract:

Pertactin (PRN) is identified as one of the most important protective immunogen of Bordetella bronchiseptica (Bb). To study the immunogenicity of region 1 (R1) of PRN, the complete coding sequence (2 040 bp) and its 5′terminal 1 173 bp fragment of the prn gene were separately cloned into the prokaryotic expression vector pGEXKG, and expressed in the E. coli BL21 (DE3) with induction by IPTG. The concentration of purified expression products, glutathione Stransferase (GST)R1 and GSTPRN were 312.6 and 207.3 μg·mL1, and the purity of them were 95.2% and 92.4%, respectively. The GSTR1 and GSTPRN showed the similar immunological reactivity in Westernblot analysis. Mice, immunized subcutaneously with two doses of purified GSTR1 or GSTPRN proteins mixed with an equal volume of Freund′s adjuvant, produced robust PRNspecific IgG antibody levels. In these two groups, all 9 mice survived intranasal challenge with three times the 50% lethal dose (LD50) of virulent Bb HH0809, whereas 3 of 9 and 7 of 9 mice survived challenge with ten times LD50, respectively. Furthermore, complete protection (10/10) against intraperitoneal (i.p.) challenge with ten times the LD50 of virulent HH0809 strain was seen in mice that were injected i.p. with 0.5 mL rabbit antiGSTR1 or antiGSTPRN serum, whilst there were no survivors in group of mice that received PRNabsorbed rabbit antiGSTR1 (0/5) or antiGSTPRN serum (0/5). In this study, we have shown that the recombinant GSTR1 protein had strong immunogenicity against Bb infection, which built a good foundation for the further research of highly efficient vaccine against bordetellosis.