Infection Control Today (02.25.2014)
Aids Weekly Plus
Infection Control Today reported on a study in which researchers from the University of California, Los Angeles (UCLA) investigated the role of nutrients in helping the immune system fight major infections such as TB. In the course of this study, the researchers discovered that vitamin A may be important in fighting TB.
The researchers describe the mechanism that vitamin A and a specific gene, called the NPC2 gene, use to help the immune system reduce the level of cholesterol in TB-infected cells. According to the researchers, TB bacteria use the cholesterol in the cell for nutrition and other needs. They hoped that reducing the cholesterol in the TB-infected cell would improve the immune system’s ability to fight the infection.
The active form of vitamin A––all-trans retinoic acid––is responsible for activating the immune system. The team investigated the role of this form of vitamin A in immune defense by comparing its effects on cells to that of vitamin D. They found that the two vitamins did not use the same mechanism to boost the immune system. Only vitamin A decreased the cells’ cholesterol levels, but vitamin A was found to be dependent on the NPC2 gene. Vitamin A induces the cell to express NPC2, which helps the cell remove cholesterol.
The researchers advise that this is an early study and additional research is required before recommending vitamin A supplementation to fight TB or other infections.
The full report, “All-Trans Retinoic Acid–Triggered Antimicrobial Activity Against Mycobacterium tuberculosis Is Dependent on NPC2,” was published in the Journal of Immunology (2014; 192 (5): 2280–2290).