On Monday 8^th, February, 2010, Assoc.Prof.Pratap Singhasiwanon, Dean, Faculty of Tropical Medicine, Mahidol University, presided over the opening ceremony "The 1^st Tropmed Lecture Series: Antibodies determined Virulence in Dengue", lectured by Dr.Scott B Halstead, MD Director, Supportive R&D&Semior Advisor Pediatric Dengue Vaccine Initiative (PDVI), in occasion of celebrating 50^th Anniversary of Faculty of Tropical Medicine. This event was held at the faculty lecture room 1, 4^th floor, Chamlong Harinasuta Building, Faculty of Tropical Medicine, Mahidol University.