“We found that not all HIV-infected individuals have similar types of neutrophils,” said Elahi. “As the HIV disease progresses, neutrophils become more activated and more potent, and in turn activate the body’s T cells, which likely causes some of the problems associated with HIV infection such as inflammation and rapid aging.”
When the neutrophils get stressed they release the protein galectin-9. This protein can interact with different immune cells once it starts to saturate the blood. The team discovered, for example, that galectin-9 strongly reacted with T-cells. That made them more susceptible to HIV infection, which led to a rushing effect and then inflammation and a hyper-immune response. Elahi’s previous work showed that patients with HIV and some forms of cancer had elevated galectin-9 blood levels. The new study identified the protein’s major source.
The study showed that neutrophils have an “alarm” reaction when shedding proteins such as galectin-9. It is linked to oxidative stress, when the body cannot naturally remove certain oxygen-containing molecules that become harmful to cells. It’s thought that this is a factor in the development of Parkinson’s disease, Alzheimer’s disease, cancer, heart failure and autism.
The findings show that preventing galectin-9 shedding could be a powerful tool in reducing many of the negative effects of HIV infection.
“We have been looking at phloretin and vitamin C in the lab and our data are very promising,” Elahi said of the antioxidant compound and vitamin. “We know that both are good at reducing galectin-9 shedding, so we believe they can prevent the hyper-activation of neutrophils. We hope that our results will spark renewed investigation into the role of neutrophils in T cell activation in other acute and chronic conditions.”
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