Suppression of host resistance to Listeria monocytogenes by acute cold/restraint stress: lack of direct IL-6 involvement.
We conducted kinetic studies to evaluate the effects of acute cold/restraint stress (ACRS) on both primary and secondary host resistance to Listeria monocytogenes (LM). The involvement of IL-6 also was investigated using IL-6 knockout (KO) mice on the BALB/c background. ACRS dramatically increased the serum corticosterone levels, indicating that ACRS activated the hypothalamic-pituitary-adrenal (HPA) axis. ACRS significantly inhibited host resistance to LM during a primary but not a secondary LM infection. During the primary infection, ACRS caused a significant delay in clearance of LM, loss of body weight, reduced food/water intake, and elevated levels of pro-inflammatory cytokines (IL-6, IL-1beta, and TNFalpha) and IFNgamma. ACRS IL-6 KO mice showed higher LM burdens than did IL-6 KO controls, suggesting that IL-6 is not required for the ACRS-impairment of host resistance. Elevated levels of IL-1beta and TNFalpha may compensate for the absence of IL-6 and maintain the ACRS-induced impairment, in that the serum and splenic IL-1beta and TNFalpha levels were significantly higher in infected ACRS IL-6 KO mice, but not in control IL-6 KO mice, as compared to respective wild type controls. ACRS appears to inhibit IL-6 independent mechanisms associated with innate immunity and/or the development of adaptive immunity, but these reactions are unable to modulate the more efficient secondary immune responses.
Cao
Ling
L
Laboratory of Clinical and Environmental Endocrinology and Immunology, Wadsworth Center, New York State Department of Health, Empire State Plaza, P.O. Box 509, Albany, NY 12201-0509, USA.
Lawrence
David A
DA
D000208:Acute Disease; D000818:Animals; D002478:Cells, Cultured; D003080:Cold Temperature / Q000009:adverse effects; D003345:Corticosterone / Q000097:blood / Q000276:immunology; D016207:Cytokines / Q000097:blood / Q000276:immunology; D007030:Hypothalamo-Hypophyseal System / Q000276:immunology / Q000382:microbiology; D007036:Hypothermia, Induced / Q000009:adverse effects; D007108:Immune Tolerance / Q000276:immunology*; D007113:Immunity, Innate / Q000235:genetics / Q000276:immunology*; D015850:Interleukin-6 / Q000172:deficiency* / Q000235:genetics; D008089:Listeria monocytogenes / Q000276:immunology*; D008088:Listeriosis / Q000235:genetics / Q000276:immunology* / Q000523:psychology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D012149:Restraint, Physical; D013312:Stress, Physiological / Q000235:genetics / Q000276:immunology* / Q000382:microbiology*
D016207:Cytokines; D015850:Interleukin-6; D003345:Corticosterone