Mphi1 and Mphi2 can be re-polarized by Th2 or Th1 cytokines, respectively, and respond to exogenous danger signals

Macrophages (Mphi) represent a dynamic cell population that develops and operates within a changing microenvironment. In parallel to Th1/Th2 cells, primary Mphi may undergo classical (Mphi1) or alternative (Mphi2) activation. Here, we investigated whether Mphi1/Mphi2 may be re-polarized by a seconda...

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Bibliographic Details
Published in:Immunobiology (1979) 2006, Vol.211 (6-8), p.473-486
Main Authors: Gratchev, Alexei, Kzhyshkowska, Julia, Köthe, Kirsten, Muller-Molinet, Isabelle, Kannookadan, Sheila, Utikal, Jochen, Goerdt, Sergij
Format: Article
Language:English
Subjects:
Cells, Cultured
Cytokines - physiology
Humans
Lipopolysaccharides - immunology
Macrophages - immunology
Macrophages - metabolism
Receptors, Cytokine - biosynthesis
Receptors, Cytokine - genetics
Th1 Cells - immunology
Th1 Cells - physiology
Th2 Cells - immunology
Th2 Cells - physiology
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Summary:Macrophages (Mphi) represent a dynamic cell population that develops and operates within a changing microenvironment. In parallel to Th1/Th2 cells, primary Mphi may undergo classical (Mphi1) or alternative (Mphi2) activation. Here, we investigated whether Mphi1/Mphi2 may be re-polarized by a secondary stimulation by Th1 or Th2 cytokines or by exogenous danger signals. We established that Mphi1IFNgamma respond to alternative activation by IL-4 and IL-10 by de novo secretion of Th2 cytokines AMAC-1 and IL-1ra, and by an increase in phagocytic capacity and a decrease in bactericidal activity. Vice versa, Mphi2 responded to classical activation by IFNgamma exhibiting reduced phagocytosis and significantly increased bacterial killing while being refractory regarding secretion of TNFalpha, IL-1beta and IL-12. In response to the bacterial danger signals LPS and MDP, both Mphi1 and Mphi2 produced IL-1beta and TNFalpha; in addition Mphi2 expressed the Th1-inducing cytokine IL-12. The ability of Mphi to be re-polarized and to react to exogenous danger signals is a precondition to down-regulate an outdated immune reaction and to retain the capacity to mount an adequate anti-bacterial response. Selective refractoriness of Mphi1 and Mphi2 to IFNgamma- and LPS-induced cytokine secretion may contribute to prevent autoimmunity.
ISSN:0171-2985