Biosafety investigations in an r-DNA production plant

Employees of a biotechnological production plant for recombinant interferon-2a have been participating in a 1-year study on occupational hygiene and the resulting biosafety aspects. Most of the employees have been employed in the plant for more than 6 years. Weekly stool samples were analysed for tetracycline (used as selection marker)-resistant coliforms as well as for rDNA (IFN gene) (interferon gene) and for the production organism. Various analytical methods, including the polymerase chain reaction, were applied to show that neither rDNA nor the production organism could be found in any of the stool samples and that there was no change or trend in the gut flora with respect to tetracycline resistance. In addition it could be shown that the tetracycline-resistance gene, as well as the rDNA, are completely inactivated in the course of the production process and thus no further recombination can take place. Blood samples were taken to show that none of the employees had anti-product antibodies. Correspondence to: E. K. Weibel