Cited research: Science 328, 508–512 (2010)

Patients with HIV are prone to life-threatening Salmonella infections, thought to be a result of HIV hijacking cellular immunity. But the real culprit may lie in the antibody-based immune system, according to a study conducted at the University of Malawi in Blantyre and the University of Birmingham, UK.

The team, led by Calman MacLennan in Birmingham, found that HIV-infected serum contains high levels of an antibody that binds lipopolysaccharide (LPS) molecules in the bacteria's outer membrane, inhibiting the normal destruction of Salmonella by the immune system. Antibodies that bind to the bacteria's outer-membrane proteins, the team finds, restore the ability to kill the invaders.

Researchers have previously proposed a Salmonella vaccine targeting LPS, but the findings suggest that this approach may actually boost infection. The outer-membrane proteins may be a better vaccine target.