Macrophage Polarisation Flashcards
What are macrophages?
Macrophages are mononuclear phagocytes that act as tissue-immune sentinels and perform critical homeostatic functions, including phagocytosing spent cells, recycling nutrients, remodelling tissues, and resolving inflammation. Macrophages mediate key antimicrobial responses against bacterial pathogens.
How do macrophages sense PAMPs?
Through cell surface and cytosolic PRRs.
Stimulation by which compounds results in M1-like macrophage polarisation? And stimulation by which compounds results in M2-like macrophage polarisation?
The M1-state occurs upon recognition of PAMPs, such as LPS, and inflammatory immune signalling, such as interferon-gamma. The M2-state entails macrophage activation from type-2 immunity-associated cytokines such as IL-3 and IL-4 or IL-10.
How do intracellular bacteria persist in macrophages?
Intracellular bacteria, like Salmonella enterica, expresses macromolecular secretion systems to inject virulence effector proteins into the host cell cytoplasm to co-opt cellular activities. Manipulation of macrophage polarisation is an important bacterial pathogenesis mechanism facilitating tissue persistence despite host immune responses.
What are granulomas and how are they formed?
Granulomas are immunological microstructures comprised of macrophages and diverse types of immune and nonimmune cells. A macrophage that is not able to kill the thing it has phagocytosed, will recruit other macrophages and other immune and nonimmune cells to surround it and, eventually, form a persisting structure called a granuloma.
