Zymosan (yeast): induction of sickness behavior and interaction with LPS

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Physiol Behav. 2003 Nov;80(2-3):177-84.

Zymosan: induction of sickness behavior and interaction with

lipopolysaccharide.

Cremeans- JK, Newberry BH.

Department of Psychology, Kent State University, 44242, Kent, OH, USA

The yeast particulate zymosan (Zy) activates innate immune system cells and

induces cytokine secretion. There is also evidence that Zy can affect

biologic responses to bacterial lipopolysaccharide (LPS) and that the

pathways by which these two agents act upon immune cells are only partially

distinct.

The present experiments assessed the ability of Zy to elicit CNS-mediated

sickness symptoms and to alter their responses to LPS.

In Experiment 1, Zy induced elements of the sickness behavior syndrome

dose-responsively in Long- rats, as indicated by reductions in

consumption of a highly palatable bait and in body temperature.

In Experiment 2, Zy exerted a priming effect, sensitizing animals to

subsequent LPS as measured by reductions in bait consumption, 24-h

laboratory chow intake, and body temperature.

Experiment 3 failed to provide evidence for LPS-to-Zy cross-tolerance but

did indicate that the administration of Zy disrupts previously acquired LPS

tolerance.

These results suggest that the specifics of exposure to microbially derived

innate immune activators have to be taken into account in investigating the

biologic bases of sickness behaviors and developing models of coinfection.

PMID: 14637214 [PubMed - in process]

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