IL-6 knock-out mice show modified basal immune functions, but normal immune responses to stress.
To better determine the role of interleukin-6 in the mechanisms that regulate stress-induced immunosuppression, we used in this study an interleukin-6-deficient mice model recently generated by gene targeting. We report here that, in basal conditions, mutant mice are characterized by altered immune functions. Natural killer activity and interleukin-2 production are lower in splenocytes of interleukin-6 deficient mice compared to those of controls, whereas Concanavalin A-induced splenocyte proliferation is comparable with that observed in wild-type mice. Moreover, splenocyte concentrations of the immunosuppressive opioid peptide beta-endorphin are higher in interleukin-6 deficient mice while serum corticosterone concentrations are unchanged. After exposure to 16 h of restraint stress, a significant suppression of the immune parameters is exhibited and a significant increase of splenocyte beta-endorphin concentrations are present in knock-out and normal animals. Finally, corticosterone is normally induced in stressed interleukin-6-deficient mice, thus demonstrating that interleukin-6 is not crucial for the activation of the hypothalamic-pituitary-adrenal axis. In conclusion, our results indicate that interleukin-6 is not a key factor in the immunosuppression observed after restraint stress.
Manfredi
B
B
Department of Pharmacology, University of Milano, Via Vanvitelli 32, Milano, 20129, Italy.
Sacerdote
P
P
Gaspani
L
L
Poli
V
V
Panerai
A E
AE
D000818:Animals; D002455:Cell Division / Q000187:drug effects; D003208:Concanavalin A / Q000494:pharmacology; D007107:Immune System / Q000276:immunology*; D015850:Interleukin-6 / Q000235:genetics*; D007694:Killer Cells, Natural / Q000166:cytology / Q000276:immunology; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D015213:Neuroimmunomodulation / Q000276:immunology*; D012149:Restraint, Physical; D013154:Spleen / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D013312:Stress, Physiological / Q000276:immunology*; D001615:beta-Endorphin / Q000378:metabolism*
D015850:Interleukin-6; D003208:Concanavalin A; D001615:beta-Endorphin