Remus Lupin was supposed to be on the H.I.V. metaphor. It was someone who had been infected young, who suffered stigma, who had a fear of infecting others, who was terrified he would pass on his condition to his son. And it was a way of examining prejudice, unwarranted prejudice towards a group of people. And also, examining why people might become embittered when they're treated that unfairly.