Food Additive May Influence How Well Flu Vaccines Work

Michigan State University researchers have linked to a common food preservative to an altered immune response that possibly hinders flu vaccines.

The study conducted in mice, presented at the 2019 Experimental Biology meeting in Orlando, Fla., April 7 at 9 am, offers up a new potential factor in vaccine effectiveness.

Tert-butylhydroquinone, or tBHQ, can be found in several food products including cooking oils, frozen meats (especially fish) and processed foods such as chips and crackers. Products do not always have to include it on.

"If you get a vaccine, this part of the immune system does not learn to recognize and fight off virus-infected cells," said Robert Freeborn, a fourth-year doctoral student who led the study with Cheryl Rockwell, badociate professor in pharmacology and toxicology. "We have been diagnosed with this disease because it is certain that we are important in carrying out an appropriate immune response to the flu."

Using various flu strains including H1N1 and H3N2, Freeborn and Rockwell focused on CD4 and CD8 T cells and incorporated tHQ in the food of mice in an comparable amount to human consumption.

"CD4 T cells are like movie directors that tell everyone else what to do," Freeborn said. "The CD8 T cells are the actors that do what the director wants."

The researchers looked at several factors including whether or not the cells showed up, were able to recognize the invading virus.

"Overall, we saw a number of CD8 cells in the lungs and CD4 cells that could identify the virus in the mice that were exposed to tBHQ," Freeborn said. "These mice also had widespread inflammation and mucus production in their lungs."

TBHQ also slow down the initial activation of T cells, reducing their ability to fight off infection. This allowed the virus to run rampant in the mice until the cells fully activated.

A second phase of the study shows the additive to the immune system's ability to remember how to respond to the virus, particularly when another strain is introduced to another time. This results in a further recovery and additional weight loss in the mice.

"It's important for the body to be able to recognize a virus and remember how to effectively fight it off," Freeborn said. "That's the point of immunity, TBHQ seems to have this process."

The research is funded by the National Institutes of Health.

Source: Michigan State University