The genetically engineered vaccine against human chorionic gonadotropin enters Phase I/II clinical trials faces a problem, its possible resolution

Objectives: To determine the causes for formation of nodules in 5 out of 9 women immunized with the genetically engineered vaccine against hCG. Material and Methods: Studies were carried out in C57BL/6 strain of mice. Vaccine was given not only by intradermal but also by intramuscular route. Results: Nodules were formed in mice when vaccine was given by intradermal route but not by intramuscular route. No antibodies were measurable after 1 µg of the Protein version of the vaccine. However the vaccine given at 2 µg dose (equivalent to 388 µg human dose) induced good antibody response in every mouse. Conclusion: Vaccine may be given by intramuscular and not by intradermal route. The dose of the vaccine for women should be at least 300 µg of the Protein version of the vaccine after priming with the DNA version of the vaccine to induce antibody response.