As a part of the safety evaluation of Pseudomonas vaccine(CFC-101), antigenicity tests were carried out in guinea pigs and mice. In active systemic anaphylaxis(ASA) test, guinea pigs showed no sign or only moderate sign(1/5) when sensitized and challenged with up to 200 ㎍/㎏. In homologous passive cutaneous anaphylaxis(PCA) test using guinea pigs, inoculation of CFC-101 alone did not produce CFC-101-specific antibody. When inoculated with 200 ㎍/㎏ plus adjuvant, challenge of 200 ㎍/㎏ produced PCA titer of 32(5/5) but challenge of 20 ㎍/㎏ did not produce CFC-101-specific antibody. In heterologous PCA test using mice, CFC-101-specific antibody was not detected when sensitized with CFC-101 alone. Some animals(3/12) showed positive PCA response when inoculated with 200 ㎍/㎏ plus alum. In passive hemagglutination (PHA) test, although no antibody was detected at 20 ㎍/㎏, inoculation of 200 ㎍/㎏ alone or with alum produced positive response in all animals. This result has already been predicted because CFC-101 is a vaccine developed for the purpose of immunization. From the above results, it can be concluded that there is no adverse antigenic potential up to 10 times clinical dose of 200 ㎍/㎏.