IL-1 Production Likely Responsible For Pertussis Vaccine Side Effects.(Brief Article)

2001 JUL 4 - (NewsRx.com & NewsRx.net) --

by N.R. Saltmarsh, staff medical writer - Researchers in Ireland have pinpointed the mechanisms behind some of the neurological side effects seen with the whole-cell pertussis vaccine (Pw).

Pw, but not the new acellular pertussis vaccines (Pa), stimulated production of the pro-inflammatory cytokine interleukin(beta) (IL-1(beta)) and hindered release of the inhibitory neurotransmitters (gamma)aminobutyric acid and adenosine in the hippocampus in a novel murine model, reported Sheila Donnelly, National University of Ireland.

Until now, the mechanisms behind Pw side effects - specifically local, systemic, and neuronal reactions, including fevers and convulsions - remained elusive because of a lack of appropriate animal models in which to study the vaccine on a molecular level, the researchers said.

"Here we describe a novel murine model wherein seizure-like behavioral changes are induced following parenteral administration of Pw," said Donnelly and coworkers.

They found that Pw increased IL-1(beta) production, which has been associated with many neurodegenerative conditions, in the hippocampus and hypothalamus. In addition, the vaccine limited the release of the inhibitory neurotransmitters (gamma)aminobutyric acid and adenosine in the hippocampus. Giving the mice an inhibitor of IL-1(beta)-converting enzyme reduced the seizure-like behavior.

Mice given Pa showed neither increases in IL-1(beta) nor behavior changes, but Pa did increase production of anti-inflammatory IL-10, said Donnelly and associates ("Whole-cell but not acellular pertussis vaccines induce convulsive activity in mice: ...