Researchers from the Duke University Medical Centre in the US have found out that even the most effective and powerful antibodies available to fight HIV fail to see the virus until and unless it has invaded a healthy cell.

A journal Nature Structural & Molecular Biology is said to have reported some previous research which suggested that two of the most robust antibodies against HIV -- called 2F5 and 4E10, specifically target the outer coating of the virus called the MPER region of gp41.

`Achilles heel', is one such area or part of the virus which can be targeted by the antibodies.

Duke Human Vaccine Institute (DHVI) director Barton Haynes who was the senior study author, according to a Duke release said "What our studies revealed, however, is that the virus actually creates two versions of this 'Achilles heel'".

He further said that since the Achilles heel is not easy to find unless the virus has already gained entry, therefore the first-responding antibodies are not of much help.

The findings are therefore of utmost importance since they help the researchers know which particular part of the virus needs to eb recognized by the antibody.