Needles may be more effective than tablets, study says

Researchers at the Trudeau Institute have made a new discovery that may allow for the delivery of more effective vaccines to prevent chronic parasitic worm infections.

The discovery, made by a team led by Dr. Markus Mohrs, stems from work with cytokines, which are the messengers used by cells of the immune system to communicate with each other. Cytokines also aid in determining the size and quality of an immune system response to infection.

Little was known about how long cytokines operate during an infection until Mohrs' team revealed when and where in the body cytokine signals are received.

According to the study, which appeared in the current issue of the journal Nature Immunology, cytokines signal to both neighboring cells and spread throughout an affected lymph node to influence cells that are not actively involved in fighting an infection.

Because of the way the cytokines react, bystander cells can respond inappropriately when a different infection is encountered by the immune system.

Dr. Mohrs' findings reveal a potential explanation for chronic infections' abilities to alter immune responses to subsequent infections or vaccination procedures. The findings are important for vaccines designed for the developing world, where chronic parasitic infections may derail vaccination programs that have proven effective in healthy individuals.

The study suggests that, because only bystander cells in the same lymph node as those responding to a parasitic infection are affected by active cytokines, people infected with gastrointestinal worms could potentially respond better to vaccines injected under the skin than those taken orally.