To clarify about the women in Africa that are seemingly immune to HIV there are many receptors on the white blood cell. HIV will attach it self to one type of receptor, inject its RNA and then the RNA will get to work replicating itself on the yummy DNA inside. I have drawn this out to show in somewhat better detail. My art is really shitty in paint, this took me about 15 minutes LOL, but should give you a better idea.
The women that are not effected by HIV do not have this "C" receptor, therefore the virus cannot attach and inject and replicate. In the future any treatment will probably revolve around this.
And for where i got this info i got this back in highschool at an HIV seminar that my advanced genetics class went to on a "field trip" of sorts. So this isnt from some teacher who thinks they know what they're talking about this is from professionals. This was about 1998 (i was a junior in a senior advanced class). My personal understanding of it may not be perfect, but the basic concept im explaining is sound if i remember correctly.
And while we're on the subject there has been news recently (like within the past couple of days) of a possible "cure". (actually there's been a few of them popping up within recent days, 3 different ones from the US and one from another country, i think it was either china or in taiwan.)