The researchers point out that antibodies stick to HIV particles, preventing them from infecting other cells and triggering their destruction by immune cells.
According to them, this antibody response starts out strong in HIV-infected individuals but eventually peters out.
They say that they wanted to discern why this happens, and thus examined the cells that make the antibodies, known as B cells.
The examination of the cells revealed that HIV gradually depletes the numbers of healthy, functional B cells.
The research group observed that individuals with high levels of HIV in their blood had lots of B cells, but they failed to replicate normally or to produce high-quality antibodies.
The researchers say that the fatigued B cells sported a protein called FCRL4, which dampens B cells' ability to respond to infection.
It is yet to be seen how HIV turns on FCRL4, the researchers add.