The production of K88 antigen by Escherichia coli and Salmonella typhimurium strains with recombinant DNA.

Expression of K88ab antigen by strains with recombinant DNA, differing in molecular weight or promoter, was subjected to investigation. Strains with recombinant DNA produced greater amounts of antigen than did field isolates. Maximal production was recorded for the E. coli C600 strain with 10.85 kb recombinant DNA with promoter P1 of the pBR322 vector. The substitution of promoter Ptac for promoter P1 did not result in an increased expression of K88ab antigen. The production of K88ab antigen by Salmonella typhimurium TM333 with recombinant DNA was on a level comparable to that of E. coli C600 or E. coli HB101 strains with the same recombinant DNA.