Cyclic shedding of HIV-1 RNA in cervical secretions during the menstrual cycle.

The association between hormone fluctuations during the menstrual cycle and human immunodeficiency virus type 1 (HIV-1) RNA shedding in cervical and vaginal secretions was examined daily for 17 HIV-1-seropositive women, for the duration of 1 cycle. Serum levels of RNA were evaluated 3 times/week. A marginally significant positive correlation between serum levels of progesterone and serum levels of HIV-1 RNA (P=.04) was observed. Cervical virus levels were significantly correlated with the number of days from the midcycle surge in luteinizing hormone (LH) (P=.008). The lowest levels of cervical HIV-1 RNA were present at the LH surge, and this nadir was followed by an increase in virus levels that reached a maximum before the start of menses. In contrast, there was no significant association between the number of days from the LH surge and the level of HIV-1 RNA in vaginal secretions (P=.4). These data support the hypothesis that the level of HIV-1 RNA in cervical secretions is influenced by the menstrual cycle, and they suggest that the risk of heterosexual transmission of HIV-1 may increase as menses is approached.

Identification of a human papillomavirus type 16-specific epitope on the C-terminal arm of the major capsid protein L1.

To characterize epitopes on human papillomavirus (HPV) virus-like particles (VLPs), a panel of mutated HPV-16 VLPs was created. Each mutated VLP had residues substituted from HPV-31 or HPV-52 L1 sequences to the HPV-16 L1 backbone. Mutations were created on the HPV-31 and -52 L1 proteins to determine if HPV-16 type-specific recognition could be transferred. Correct folding of the mutated proteins was verified by resistance to trypsin digestion and by binding to one or more conformation-dependent monoclonal antibodies. Several of the antibodies tested were found to bind to regions already identified as being important for HPV VLP recognition (loops DE, EF, FG, and HI). Sequences at both ends of the long FG loop (amino acids 260 to 290) were required for both H16.V5 and H16.E70 reactivity. A new antibody-binding site was discovered on the C-terminal arm of L1 between positions 427 and 445. Recognition of these residues by the H16.U4 antibody suggests that this region is surface exposed and supports a recently proposed molecular model of HPV VLPs.