Microbicides 2004 Microbicides 200428-31 March 2004, Hilton London MetropoleThe conference42 million men, women and children worldwide were living with HIV by the end of December 2002 (source: UNAIDS), including five million newly-infected during that year alone. Another 45 million people will become infected between 2002 and 2010, unless the current transmission rates can be vastly reduced. Of the 42 million, 29.4 million live in sub-Saharan Africa and 58% of them are women. Not only are women more susceptible to HIV infection, many are powerless to insist on the use of condoms or other methods of protecting themselves. In this context, and with the knowledge that an effective HIV vaccine is unlikely to be available for several years, the need for an effective topical microbicide grows ever more urgent. 2004 should prove to be a landmark year in the field of microbicide development as the first Phase III trials of novel products are due to start – the next step along the road to making a microbicide available to the millions worldwide in desperate need of protection.The aims of the Microbicides 2004 conference are to:Report novel or innovative work in the microbicides fieldProvide updates on recent microbicides research, divided into three tracks: basic science, clinical science, and behavioural science (including public health and the microbicide marketplace)Provide a forum for the discussion of new developments in microbicide research including ethical, clinical, behavioural and methodological issuesPresent opportunities for knowledge-sharing between microbicide researchers, public-health workers and advocacy organisations.There will be an opening ceremony on the evening of Sunday 28 March at which politicians, policy makers and the international media are expected. The conference will run for a full three days, each of which will contain:Scientific overviews and presentations with plenary sessions, invited lecturers and presentations of original researchWorkshops to review issues unique to microbicides such as trial design and outcome measures, and ethical issues in the clinical trials of microbicidesPoster sessions. Focus on LondonFollowing the successful Microbicides conferences in Washington in 2000 and Antwerp in 2002, March 2004 sees the focus move to London.The venue is the Hilton Metropole Hotel, two minutes by taxi from Paddington station and the Heathrow Express, with a journey time from the airport of 15 minutes. The hotel is in walking distance of Hyde Park and London’s main shopping streets, and close to Imperial College. Accommodation will be available at the venue and other hotels in the vicinity.London in March offers a variety of diversions for out-of-conference relaxation, including sight-seeing and shopping; the arts and the theatre; and pubs, clubs and restaurants to suit every taste. Conference staff will be on hand to help delegates plan their spare time.To book your place or find out more information, e-mail info@microbicides2004.org.uk or telephone the Event Office on +44 (0) 20 7720 4411
Oral: invited speaker Oral: Track A Oral: Track B Oral: Track C Poster: Track A Poster: Track B Poster: Track C Abstract only Authors

02352 THETA-DEFENSINS PROTECT CELLS FROM INFECTION BY HERPES SIMPLEX VIRUS 

Yasin, Bushra*,
Wang, W.**, Pang, M.*, Cheshenko, N.***, Hong, T.**, Waring, A. J.**, Herold, B. C.***, Wagar, E. A. **, and Lehrer, R. I.**
Depts. of Pathology and Laboratory Medicine* and Dept. of Medicine**David Geffen School of Medicine At UCLA, Los Angeles, CA 90095, Dept. Pediatrics & Microbiology***, Mount Sinai Medical School, New York, NY 10029, USA

Theta (q) ) defensins are cyclic octadecapeptides that are encoded by ?-defensin (DEFT) genes. Intact DEFT genes exist in various non-human primates, including Old World monkeys (rhesus and pigtail macaques), lesser apes, and orangutans. Three rhesus ?-defensin peptides (RTD-1, -2, and –3) were purified from the leukocytes and bone marrow of rhesus macaques. However, although the human genome contains at least six different DEFT genes, all of them contain a premature stop codon that stops translation. Thus, ?-defensin peptides are not present in human neutrophils. Retrocyclins 1, -2, and -3 are ?-defensins that could be expressed in human leukocytes if the human DEFT gene sequences lacked the premature stop codon. Previous studies have shown that retrocyclin-1 protected human cells from infection by T and M-tropic strains of HIV-1.

Herpes simplex virus (HSV) is also a sexually-transmitted viral pathogen, and herpes infections may predispose to infection by HIV-1. We tested the ability of 20 synthetic ?-defensins to protect ME-180 cervical epithelial cells from infection by HSV-1 and HSV-2 using an MTT assay. The peptides included RTDs 1-3 and retrocyclins 1-3. We also tested 14 retrocyclin analogs, including the retro, enantio and retroenantio forms of retrocyclin-1. Peptides and viruses were co-incubated for 2 h before being added to target cell monolayers. Cells were then incubated at 37oC. for 72 h and viral infection and cytotoxicity were assessed. To study the mechanisms of retrocyclin action, we examined the binding of retrocyclin-2 to the HSV-2 glycoprotein gB2 in surface plasmon resonance studies. Temperature shift experiments were employed to determine whether q-defensins blocked viral attachment, penetration, and nuclear transport. To delineate the steps inhibited by theta-defensins, synchronized infections were induced and monitored to examine transport of the tegument protein VP 16 to the nucleus or expression of the immediate early gene product, ICP4.

Retrocyclin-2 provided 100% protection from HSV-2 without causing cytotoxicity or requiring pre-incubation with the virus. Retrocyclin-2 additionally blocked viral attachment and markedly diminished HSV-2 nuclear translocation of VP 16 and ICP4 expression. Human ?-defensins HNP 1-3 also protected human cells from HSV-2 but had little effect on binding. Also, retrocyclin-2 bound to immobilized glycoprotein gB2 with high affinity (KD, 13.3 nM) but did not bind to enzymatically deglycosylated gB2. Given its small size (18 residues), minimal cytotoxicity, and effectiveness in inactivating both HSV-2 and HIV-1, retrocyclin-2 provides an intriguing prototype for topical viral microbicide development.

Dr. Bushra Yasin
c/o Dr. Elizabeth Wagar, AL-206 CHS, UCLA Dept. of Pathology and Laboratory Medicine, 10833 Le Conte Avenue, Los Angeles, CA 90095-1732
(Telephone) 310-794-7110 (Fax) 310-206-8175 (E-mail) byasin@mednet.ucla.edu