Phagocytosis. Inflammation

Phagocytosis is a process of bacteria engulfment and their killing. The phagocytic cells of mammals belong to two complementary systems, the myeloid and mononuclear-phagocytic systems. The myeloid system consists of cells that phagocyte rapidly, however they are not able of sustained effort. Tthey are represented by neutrophils and eosinophils. In contrast, cells of the mononuclear-phagocytic system act more slowly but are capable of repeated phagocytosis. Mmonocytes and macrophages are principal cell responsible for. Process of phagocytosis can be divided into several steps: chemotactic movement of phagocytes towards invading bacteria, opsonisation and recognition of bacteria by specific receptors, their engulfment and phagolysosome formation, bacteria killing and resolution. Bacteria can be killed by oxygen or nitrogen dependent mechanisms and by various antibacterial substances.

Inflammation is a defence mechanism, which aims to kill invading germs, restrict a damage of an affected tissue and restore a previous physiological state. Process of inflammation can be also divided into several steps: recruitment of inflammatory cells into a site where germs entered the body, local inflammatory response, systemic response, and resolution. Local inflammatory response comprises acute vascular response represented by vasodilation and increased vascular permeability, acute cellular response mediated mainly by neutrophils, chronic cellular response mediated by monocytes and macrophages in earlier steps and dendritic cells and lymphocytes, when adaptive immune response is requiered to eradicate the invaded germs. Cytokines released by macrophages (IL-1, IL-6, TNF) induce a systemic response. Its basic signs are: fever, malaise, joint aches ...., an increased production of neutrophils by the bone marrow and their output (leucocytosis ), an increased level of plasma proteins (acute phase proteins: CRP, MBL, ....), an increased RBC sedimentation rate etc.

Attachment   Date Size Availability [?] Clinically sensitive [?] Licence
 Phagocytosis 16.3.2012 4.23 MB registered user


Related contributions: