Sperm as a noninvasive gene delivery system for preimplantation embryos.

OBJECTIVE: To determine if sperm could be manipulated to be a noninvasive transport carrier for the delivery of gene fragments to the blastocyst. DESIGN: Sperm cells carrying foreign DNA fragments from human papillomavirus (HPV) types 16, 18, 31, and 33 were allowed to migrate from one end of an artificial reproductive tube and to come in contact with hatching mouse blastocysts at the other end of the tube. The blastocysts were then washed and analyzed for the presence of the foreign DNA fragments. SETTING: Clinical and academic research environment. MAIN OUTCOME MEASURE: Detection of amplified products from transferred foreign DNA using the polymerase chain reaction and primers targeted at the E6-E7 region for different HPV types. RESULTS: Polymerase chain reaction analyses showed transference of DNA HPV type 18 to the blastocysts. Not all types of DNA fragments were transferred equally. CONCLUSION: The results suggested the possibility of using sperm as a noninvasive gene delivery system for passing on gene fragments to preimplantation embryos. It was demonstrated that certain DNA fragments were easier to deliver than others, indicating the necessity for exploring all the factors involved in the mechanism of the transference process. The study also serves to highlight the possibility of unintentional transmission of viral or bacterial DNA to the developing embryo via the sperm.