We also thank Liz Verrecchio (Main Line Fertility Center, Bryn Mawr, PA), M. cells. The antiviral activity and mechanisms of action of PDB-based compounds were dependent on oligomer size, with smaller molecules preventing reverse transcription and larger oligomers obstructing viral entry. Mouse monoclonal antibody to Keratin 7. The protein encoded by this gene is a member of the keratin gene family. The type IIcytokeratins consist of basic or neutral proteins which are arranged in pairs of heterotypic keratinchains coexpressed during differentiation of simple and stratified epithelial tissues. This type IIcytokeratin is specifically expressed in the simple epithelia lining the cavities of the internalorgans and in the gland ducts and blood vessels. The genes encoding the type II cytokeratinsare clustered in a region of chromosome 12q12-q13. Alternative splicing may result in severaltranscript variants; however, not all variants have been fully described Importantly, irrespective of molecular size, PDBs potently inhibited computer virus illness and transmission within genital cells samples. Furthermore, the PDB inhibitors exhibited superb toxicity and stability profiles and were found to be safe for vaginal application model of murine cervicovaginal toxicity and by conducting efficacy screening in the presence of seminal plasma and genital secretions. Finally, we set out to assess the capabilities of PDB-based compounds to inhibit HIV-1 transmission inside a polarized human being cervical explant model, as this may represent an important preclinical predictor of microbicide effectiveness. MATERIALS AND METHODS Ethics statement. Healthy donor blood and seminal plasma samples were collected following Drexel University Institutional Review Board (IRB) approval. Normal human ectocervical tissue samples were acquired from HIV-1-seronegative premenopausal women as part of their standard care. The genital tissue samples were deidentified and thus exempted from IRB review. Eight-week-old Swiss Webster and C57BL/6 (The Jackson Laboratory, Bar Harbor, ME) female mice were housed in animal facilities in accordance with the Drexel University College of Medicine Institutional Animal Care and Use Committee (IACUC) regulations on the care and protection of laboratory animals. Female rhesus macaques (HIV-1 fusion and contamination assays. The methodology used for the antiviral activity assays as part of the standard algorithm for screening candidate microbicides was followed as previously described (31). Cell viability and efficacy were tested in parallel using a commercially available soluble tetrazolium-based procedure (CellTiter 96 cell proliferation assay; Promega, Madison, WI). Fusion assays assessed the abilities of the compounds to block cell-to-cell fusion mediated by the HIV-1 envelope (Env) present on one Tat-expressing cell line that interacts with CD4 and CXCR4 or CCR5 coreceptors expressed on a separate target cell line possessing a long terminal repeat (LTR)–galactosidase (-gal) reporter. Compounds were used to pretreat target cells (P4-R5 MAGI or MAGI-CCR5) for 1 h at 37C, prior to the addition of HL2/3 cells (expressing HIV-1 Tat and CXCR4-tropic Env from HXB2/3gpt) or HeLa-R5-16 cells (expressing HIV-1 Tat and Pronase E CCR5-tropic Env). The incubation was continued for 48 h, after which fusion was monitored by measuring -gal Pronase E activity (Tropix Gal-Screen; Applied Biosystems, Grand Island, NY). Cell-free HIV-1 contamination assays were used to detect the capacities of PDB compounds to block the infection of MAGI and TZM-bl cells. The target cells were preincubated with compounds for 15 min at 37C, following contamination with 10 50% tissue culture infectious doses (TCID50) of HIV-1IIIB or HIV-1Ba-L. The PDBs were also evaluated in a altered assay in which the Pronase E compound and virus were preincubated for 1 h prior to the addition of the target cells. At 48 h postinfection, Pronase E -gal activity was determined by chemiluminescence. CD4-dependent cell-to-cell transmission assays were performed to determine whether PDB 14-mer (PDB14) prevented the transmission of HIV-1 from an infected cell to a target cell. CD4-positive GHOST (3) X4/R5 cells served as targets. The virus-transmitting cells were either H9 cells chronically infected with HIV-1SK1 (CXCR4 tropic) or MOLT4-CCR5 cells chronically infected with HIV-1JR-CSF (CCR5 tropic). Twenty-four hours prior to the assay, the target cells were seeded into 96-well flat-bottom plates. On the day of the assay, CD4+ GHOST (3) X4/R5 target cells were 100% confluent, and the HIV-1-transmitting cells were treated with mitomycin C (200 g/ml) (Sigma-Aldrich) for 60 min at 37C. PDB14 was added to the target cells, followed by the addition of 1 1,000 (CXCR4-tropic) or 4,000 to 8,000 (CCR5-tropic) effector cells. The HIV-1-transmitting cells and targets were incubated with PDB14 for 4 h, followed by three washes. Twenty hours later, the wells were.