Inflammatory Mediators


Cytokines and chemokines are soluble inflammatory mediators that are naturally produced during an inflammatory response. The type of immune response (pro‐ or anti‐inflammatory, cell mediated or humoral) elicited by these molecules largely depends on the initial cytokines released in response to bodily injury or pathogen invasion. The characteristic signs of inflammation: redness, swelling, heat and pain are the result of coordinated, intricate signalling responses by these soluble mediators that primarily facilitate cellular infiltration to the site of infection. The nature of the immune response is further complicated by the fact that several cytokines can promote both pro‐ and anti‐inflammatory responses. Although cytokines and chemokines are often effective at resolving inflammation, aberrant cytokine and chemokine signalling have been shown to contribute to many autoimmune diseases.

Key Concepts

  • Fine‐tuned immune signalling is critical for resolution of potentially harmful stimuli.
  • Inflammatory mediators are the molecules responsible for immunological homeostasis.
  • Cytokines and chemokines link the innate and adaptive immune systems.
  • Inflammatory mediators regulate physiological processes distinct from the immune system.
  • Cytokines and chemokines are powerful signalling proteins.
  • Arachidoic acid is synthesised into prostaglandins and leukotrienes.
  • Activation of the complement system yields anaphylatoxin production.

Keywords: inflammation; cytokine; chemokine; interleukin; macrophage activation; cellular infiltration; neutrophil; leukotrienes; prostaglandins; complement

Figure 1. Overview of the primary effector cells and their functions that contribute to inflammation.
Figure 2. Naïve CD4+ T helper (TH) cell differentiation into distinct effector subsets. Naïve CD4+ T cells are activated by dendritic cells within the lymph node. The TH subset is determined by the cytokine milieu in the lymph node during antigen presentation.


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Alvine, Travis D, Knopick, Peter L, Nilles, Matthew L, and Bradley, David S(Sep 2015) Inflammatory Mediators. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1002/9780470015902.a0000945.pub2]