Integration of immunodeficiency virus in oocytes via intracytoplasmic injection: possible but extremely unlikely

Objective: To determine if human oocytes can be infected with HIV-1 via intracytoplasmic injection and to determine the infection threshold. Design: Twenty-eight donated immature and unfertilized human oocytes from HIV-negative women were injected with 4 x 10(4) HIV-1 virions and 13 oocytes were used as uninjected controls. To determine the infection threshold, 543 cat oocytes were injected with 4 x 10(4), 4 x 10(2), or 40 copies of feline immunodeficiency virus (FIV) and 376 oocytes were used as controls. Setting: Academic hospital. Patient(s)/Animal(s): Donated immature human oocytes and mature cat oocytes. Intervention(s): Injection with HIV-1 or FIV. Main Outcome Measure(s): Viral integration as measured by fluorescent in situ hybridization with HIV-1-specific probes or by nested FIV polymerase chain reaction. Result(s): We detected viral integration in three of 28 (11%) human oocytes injected with 4 x 10(4) copies of HIV-1. When injected with high dose FIV (4 x 10(4) copies) 16%-49% of cat oocytes showed viral integration. This decreased to 2%-7% and 0.6%-1.8% when an intermediate (4 x 10(2) copies) or low (40 copies) dose was injected, respectively. Conclusion(s): Human and cat oocytes can be infected with HIV-1 and FIV respectively, when injected with high amounts of virus. The probability of viral integration is extremely low when small amounts of virus particles are injected. Taking into account the small volume injected during intracytoplasmic injection, the chances of viral integration are 0.00002%. (Fertil Steril (R) 2012; 98: 173-7. (C) 2012 by American Society for Reproductive Medicine.)