He worked on the mechanism of activation of the immune system by viral antigens. He was awarded a D.Phil. in 1997 for his thesis titled The processing and presentation of viral antigens.[13] After graduation, he attended Harvard Medical School, where he earned his Doctor of Medicine (M.D.) degree in 2000.[14] Between 2000 and 2003 he worked as a resident in internal medicine at the Massachusetts General Hospital. From 2003 to 2006 he trained in oncology as a Fellow at the Dana-Farber Cancer Institute (under Harvard Medical School) in Boston, Massachusetts.[15][16]