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Innate Response Essay

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The immune system is composed of two parts firstly the innate system and secondly the adaptive system. The innate response is the first line of defence and relies on pattern recognition receptors (PRRs) to recognise specific pathogen associated molecular patterns (PAMPs) and provide a rapid response to the recognised pathogen. This system also has the complement system and phagocytic cells as its disposal. Pathogens expresses PAMPs which activate antigen presenting cells (APC), such as dendritic cells (DC), through ligation of PRR (e.g. Toll-like receptors) found on the APC surface. The adaptive immune system, is the specific response against the pathogens. This response begins with the activation of T-cells, CD4+ T-helper (TH) cells, CD8+ …show more content…

DC are crucial in pathogen recognition and initiating specific immune responses to destroy pathogens. DC phagocytose a diverse selection of antigens and present them to cells as peptides bound to MHC I/II products.
DCs can be immature or mature, immature DCs are found in tissues throughout the body allowing them to monitor the surrounding environment for pathogens and can provide a rapid response to any foreign bodies. DCs become mature when they receive a “danger” signal through PRRs, during the maturation process the cells T cell-stimulating capacity will increase, it will also increase in size allowing an increase in levels of cell surface antigens (e.g. MHC class I/II and CD40) which is important in T cell activation.
DCs will uptake the antigen causing inflammatory cytokines production (e.g. IL-2, INFµ, TNFα) and chemokines allowing the antigen loaded DC to migrate to lymphoid organs. Once there the naïve T cells have; the antigen that stimulated specific TCRs and polarising factors that determine which T-cell is produced - TH1, TH2 or TH17. The T-cells undergo structural changes so that they are programmed for apoptotic

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