An individual has a wound on the hand that gets infected with Staphylococcus aureus. Trace the entire innate immune response, assuming that the Staph is not cleared and that this is the first time this individual has seen S. aureus. The answer includes, but is not limited to: a discussion of the phagocytic response, cells involved, and mechanisms of killing; any complement activation that is possible; and the initiation of inflammatory response and outcome resulting from inflammation.
When bacteria are first encountered by the immune system, one of the first cell types to counter the infection is the neutrophil. These cells recognize bacteria by means of cell surface receptors such as mannose receptors, that bind onto common pathogen-associated molecules such prokaryotic carbohydrates. Both neutrophils and macrophages will phagocytose the bacteria, taking them into intracellular vesicles where they can be destroyed. Phagocytes release several antimicrobial substances into the phagocytic vesicle, for example enzymes such as lysozyme and cathepsins, that attack the bacterial cell walls. Phagocytes also release reactive oxygen and nitrogen species into the vacuole, which are toxic for the bacteria.
Bacteria in the tissue can activate the alternate pathway of ...
This solution gives an overview of the entire innate immune response to a bacterial infection of the skin, using Staphylococcus aureus as an example.