In: Biology
An inflammatory response is vital to eliminating an infectious agent. Fully describe inflammation, addressing each of the following in the description. (You may use diagrams) a. Complete description of the inflammatory response (be specific) b. Methods (more than one) of the initiation of inflammation c. At least 3 aspects of the immune response that are enhanced by inflammation and how they are enhanced.
A.
The inflammatory response (inflammation) occurs when tissues are injured by bacteria, trauma, toxins, heat, or any other cause. The damaged cells release chemicals including histamine, bradykinin, and prostaglandins. These chemicals cause blood vessels to leak fluid into the tissues, causing swelling. This helps isolate the foreign substance from further contact with body tissues.
The chemicals also attract white blood cells called phagocytes that eat germs and dead or damaged cells. This process is called phagocytosis. Phagocytes eventually die. Pus is formed from a collection of dead tissue, dead bacteria, and live and dead phagocytes.
B. Activation of
Inflammatory pathways impact the pathogenesis of a number of chronic diseases, and involve common inflammatory mediators and regulatory pathways. Inflammatory stimuli activate intracellular signaling pathways that then activate production of inflammatory mediators. Primary inflammatory stimuli, including microbial products and cytokines such as interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α), mediate inflammation through interaction with the TLRs, IL-1 receptor (IL-1R), IL-6 receptor (IL-6R), and the TNF receptor (TNFR). Receptor activation triggers important intracellular signaling pathways, including the mitogen-activated protein kinase (MAPK), nuclear factor kappa-B (NF-κB), and Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathways.
NF-κB pathway
The NF-κB transcription factor plays important roles in inflammatory, immune response, survival, and apoptosis processes. The NF-κB family includes five related transcription factors: P50, p52, RelA (p65), RelB, and c-Rel. NF-κB activity is induced by a range of stimuli, including pathogen-derived substances, intercellular inflammatory cytokines, and many enzymes. Under physiological conditions, IκB proteins present in the cytoplasm inhibit NF-κB. PRRs use similar signal transduction mechanisms to activate IκB kinase (IKK), which is composed of two kinase subunits, IKKα and IKKβ, and a regulatory subunit, such as IKKγ. IKK regulates NF-κB pathway activation through IκB phosphorylation. IκB phosphorylation results in its degradation by the proteasome and the subsequent release of NF-κB for nuclear translocation and gene transcription activation. This pathway regulates pro-inflammatory cytokine production and inflammatory cell recruitment, which contribute to the inflammatory response.
C.