Virus p30-related protein in follicular fluids and C virus-like particles on the cell membrane of the human oocyte.

Fluids from 208 follicles were analyzed with respect to the concentration of estradiol and progesterone and to the presence of RD 114 retrovirus p30-related protein (rp), assuming that such a protein indicates the presence of C-virus particles in the follicular fluids. The results obtained showed that 60-80% of the follicular fluids within the same range of steroid hormone levels contained virus p30 rp. Electron microscopy showed 80-nm virus-like particles, more or less well preserved, in about half of the number of oocytes examined. Negative staining of purified follicular fluid particles showed ring-like structures with a size of 100-200 mm. It is concluded that the presence of virus p30 rp in follicular fluids is correlated neither to a certain steroid hormone concentration nor to the oocyte capability to become fertilized and cleave. The observed expression of an endogenous virus genome during oocyte maturation strengthens the hypothesis that this type of genome is active at early developmental stages.