Let's all remember to keep in mind that this is what we've all had protecting us this long, so don't go and be careless now thinking you aren't gonna' get it. It still just takes ONE time.
Although it is VERY interesting, and cool that at least our body defends certain things like that.
If you read the article, you'll note that the incidence of transmission of HIV is extremely low. HPV however, will be transmitted 100 percent of the time.
The most notable, to me, aspect of this study is that Langerhans cells are located in the mucosa. For men, that means their foreskin, it seems this study is at odds with all the studies out of Africa that are advocating mass circumcision. Probably the biggest issue at work here is the health of a person's immune system. If one is malnourished, suffering from malaria, etc, then the protective mechanism may not be as strong.