Sickness behavior in mice deficient in interleukin-6 during
turpentine abscess and influenza pneumonitis.
Kozak, Wieslaw, Valeria Poli, Dariusz Soszynski, Carole A. Conn, Lisa
R. Leon, Matthew J. Kluger.
Institute for Basic and Applied Medical Research, The Lovelace
Institutes, 2425 Ridgecrest Dr. SE, Albuquerque, New Mexico 87108,
USA, Istituto di Ricerche di Biologia Molecolare IRBM P. Angeletti,
00040 Pomezia (Rome), ITALY
APStracts 3:0341R, 1996.
Kozak, Wieslaw, Valeria Poli, Dariusz Soszynski, Carole A. Conn, Lisa
R. Leon, and Matthew J. Kluger. Sickness behavior in mice deficient
in interleukin-6 during turpentine abscess and influenza pneumonitis.
American Journal of Physiology (Regulatory Integrative Comp.
Physiol.). Interleukin-6 (IL-6), among other cytokines, is thought to
be involved in the regulation of sickness behavior (e.g., anorexia,
cachexia, fever, lethargy) induced by infections (bacterial and viral
origin) and sterile tissue necrosis (burns, surgical traumas). Mice
deficient in IL-6 (IL-6 KO) were generated by gene targeting.
Homozygous IL-6 KO male and female mice, and their appropriate
controls, were implanted with biotelemeters to monitor body
temperature (Tb) and motor activity (Act). Normal circadian rhythms
in Tb and Act as well as rates of food intake and weight gain did not
differ significantly between sex-matched IL-6 KO and control groups
at 30[acute]iC in a 12/12 h light/dark cycle. Sterile tissue damage
was induced in mice by subcutaneous injection of turpentine (0.1 ml;
left hindlimb). Influenza pneumonitis was induced by intranasal
inoculation of mouse adapted influenza A virus (17.5 PFU). Lack of
IL-6 completely prevented fever, anorexia and cachexia due to
turpentine abscess in both sexes. It did not prevent lethargy,
although IL-6 KO mice recovered to normal Act significantly sooner
than wild type mice. Symptoms of sickness were only slightly modified
during influenza virus infection in IL-6 KO mice. Attenuation of
sickness behavior was more pronounced in IL-6 KO female than in male
mice. We conclude that, although IL-6 is induced during both
turpentine abscess and influenza infection, this cytokine appears to
be more critical in induction of the symptoms of sickness behavior
during sterile tissue abscess than during influenza infection.
Received 6 June 1996; accepted in final form 12 August 1996.
APS Manuscript Number R320-6.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 19 September 1996