'How body becomes prone to rotavirus infection decoded'

In a first, researchers have discovered how a brief disruption in the guts of pre-born mice can compromise their adult immunity to rotavirus infection, which kills nearly 2,15,000 humans annually, mostly in the developing world.

The scientists, including those from the University of Toronto in Canada, inhibited a natural chemical process in the intestine called the 'lymphotoxin pathway' which plays a major role in the development of the immune system.

The findings, of their study, published in the journal Science Immunology, revealed that this inhibition prevented a robust antibody response in adult mice to rotavirus.

According to the researchers, this early disruption limits the ability of the immune system to later trigger and generate the production of Immunoglobulin A (IgA) antibodies against the virus.

They added that disturbing the pathway also interferes with the functioning of gut cells supporting the antibody response -- the mesenteric lymph node stromal cells.

"It was surprising that these non-immune stromal cells were so important to the immune response," said Jennifer Gommerman, study co-author from the University of Toronto.

Disturbing the stromal cells, she said, affected the ability of immune B cells to produce IgA that neutralized rotavirus.

"We're just beginning to understand the influence these stromal cells can have," Gommerman added.

Adding to the findings, the scientists said there is a growing importance to study the environment in which immune cells function.

"We typically think of a lymph node as just a bag of lymphocytes, but there is also this supporting structure that clearly has an active role in shaping immunity," Gommerman said.

While several dysfunctions in the immune system may lead to reduced immunity against rotavirus in low-income countries, the researchers said, the findings of the current study offer a hint that prevention may be possible.

In the future, Gommerman said, the findings may lead to an intervention where a pregnant woman in a resource-depleted area may take a dietary supplement to ensure proper development of tissues that support immunity in her growing baby.

While this kind of intervention is likely a long way off, she said, a more immediate next step is a collaborative study on IgA immune responses to other pathogens such as norovirus -- another highly contagious disease.