We know that Minocycline hydrochloride, also known as minocycline (structure), is a  broad spectrum tetracycline antibiotic, and has a  broader spectrum than the other members of the group. It is a bacteriostatic  antibiotic. It is primarily used to treat acne  and other skin infections as well as lyme disease. It may be used to treat certain strains of MRSA infection  and disease caused by drug resistant Acinetobacter. Its also used in DMARD (Disease-Modifying Anti-Rheumatic Drug) for RA. 
Now, Johns Hopkins scientists have found that this safe and inexpensive  antibiotic (minocycline),   effectively  targets infected immune cells in which HIV, the virus  that causes AIDS, lies dormant and prevents them from reactivating and  replicating. 
As per the claim by the researchers, minocycline, likely will improve on the current treatment regimens of  HIV-infected patients if used in combination with a standard drug  cocktail known as HAART (Highly Active Antiretroviral Therapy).  Though HART is really effective in keeping down active replication, minocycline is  another arm of defense against the virus. 
Dr. Janice Clements lead researcher claims that,  unlike the drugs used in HAART which target the virus,  minocycline homes in on, and adjusts T cells, major immune system  agents and targets of HIV infection. and  minocycline  reduces the ability of T cells to activate and proliferate, both steps  crucial to HIV production and progression toward full blown AIDS. 
The idea for using minocycline as an adjunct to HAART resulted when the  Hopkins team learned of research by others on rheumatoid  arthritis patients showing the anti-inflammatory effects of  minocycline on T cells. Interestingly the same researchers earlier found that  minocycline  treatment had multiple beneficial effects in monkeys infected with SIV,  the primate version of HIV. In monkeys treated with minocycline, the virus  load in the cerebrospinal fluid, the viral RNA in  the brain  and the severity of central nervous  system disease were significantly decreased. The drug was also  shown to affect T cell activation and proliferation.  
The team used molecular markers to discover that minocycline very  selectively interrupts certain specific signaling pathways critical for T  cell activation. However, the antibiotic doesn't completely obliterate T  cells or diminish their ability to respond to other infections or  diseases, which is crucial for individuals with HIV. Researchers conclude that,  this new understanding about minocyline's effects on a T cell  might help to  find even more drugs that target its signaling pathways.
At Johns Hopkins and elsewhere, scientists are now testing whether  giving HIV patients minocycline benefits them, let us hope for the positive results.... 
Ref : http://www.usnews.com/science/articles/2010/03/26/existing-antibiotic-might-help-keep-wraps-on-aids-virus.html 
