HIV ‘boots’ itself into the body precisely by getting the immune system to react to it and thereby make lots of new activated CD4 cells to infect: if the CD4 cells don’t recognise it as foreign, no infection gets established. What these cells appear to do is to suppress the response in CD4 cells to HIV by inducing the CD4 cells to change the MHC molecules on their surface. The job of these molecules is to detect foreign proteins