recombinant toxin-coregulated pilus a (tcpa) as a candidate subunit cholera vaccine.

background   and   objectives:    the   toxin   co-regulated   pilus   a   (tcpa)   has   been   described   as   a   criti- cal  pathogenicity  factor  of   vibrio  cholerae .  tcpa  is  a  candidate  for  making  subunit  vaccine  against  chol- era.  the  aim  of  this  study  was  to  produce  a  candidate  vaccine  by  expressing  recombinant  tcpa  in   e.  coli . materials and methods: in this study, the toxin co-regulated pilus a gene from el-tor, v. cholerae subspecies, was am- plified by pcr and sub-cloned into prokaryotic expression vector pgex4t1. e. coli bl21 (de3) was transformed with pgex4t1- tcpa and gene expression was induced by iptg and purified by gst resin. the integrity of the product was confirmed by western blot analysis using a standard rabbit anti- v. cholerae antibody. sera reactivity of infected individuals was further analyzed against the recombinant tcpa protein. results: the concentration of purified recombinant protein was calculated to be 8 mg/l of initial culture. the in- tegrity of product was confirmed by western blot analysis using a standard rabbit anti v. cholerae antibody. sera re- activity  of  infected  individual  was  further  analyzed  against  the  recombinant  tcpa  protein.  the  obtained  data  in- dicated  that  recombinant  tcpa  protein  from   v.  cholerae   was  recognized  by  patient  serum  and  animal  sera. conclusion: these results show that the recombinant tcpa is antigenic and could be used in a carrier host as an oral vaccine against cholera.