Evaluation of 3,3′-Diindolylmethane with Gardasil Quadrivalent HPV Vaccine in K14-HPV16-Transgenic Mice Cervical Histology

Background: The effects of 3,3'-diindolylmethane (DIM) together with the Gardasil vaccine on cervical histology were evaluated using the K14-HPV16-transgenic mouse model. The possibility that DIM could enhance the efficacy of this preventive vaccine in this model was explored. Materials and Methods: Transgenic mice were given 1000 mg/kg of DIM in the diet for 28 weeks. The mice were injected with Gardasil Quadrivalent HPV vaccine. Some mice were sacrificed at 28 weeks. Other groups were removed from the DIM diet after 28 weeks to a diet with no DIM for either 4 or 8 weeks. Results: Cervical histology indicated that a high percentage of transgenic mice fed DIM and vaccinated with Gardasil manifested normal cervical epitheliums at 4 weeks after DIM discontinuation. Conclusion: Vaccination pre-supplemented with DIM may provide with a window of protection of at least four weeks in this transgenic model. However, extrapolation to the effect in humans is beyond the limited scope of the histological data presented here.