The innate immune system is the defense mechanism that is activated immediately or shortly after the body is exposed to invading microorganisms.1 This system is quick in response and does not have a memory, meaning it doesn’t need previous exposure to the foreign microbe’s antigen before it can be activated.2 The adaptive immune system consists of antigen-specific immune responses.2 This system is slow in response because after it is exposed to an antigen, it needs time to process the antigen and then recruit the proper cells to elicit an immune response.2 Thus the adaptive immune system requires more time.2 The adaptive immune system does have a memory because subsequent exposure to the same antigen will trigger a much faster response.2
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Infection occurs when pathogens are able to cross the epithelial surfaces of the body and overcome the host’s innate immune system.8 When the pathogen enters the tissues, they are first recognized by macrophages.8 MCP1 promotes monocytes to become macrophages in the tissues.9 Neutrophils will also be recruited to the site of infection.8 IL-8 promotes neutrophils to exit the bloodstream and enter nearby tissues.9 During an infection, inflammation serves to fight the infection.8 TNF-alpha induces a local inflammatory response which helps control infections .9 A number of inflammatory responses such as pain, swelling, heat, and redness, can occur at the infection site.8 CRP is secreted in response to inflammation and helps activate complement, binds to Fc receptors, and enhances phagocytosis.10 IL-6 increases body temperature and initiates acute phase response.9 IL-1-Beta induces fever, T-cell & macrophage activation.11 Also during inflammation, the surfaces of blood vessel endothelium express cell-adhesion molecules known as ICAM- 1 and ICAM-2.9 If there is tissue damage, fibrinogen helps form blood clots to stop bleeding.12 PAI1 is the main inhibitor of plasminogen activators (inhibits the breakdown of blood clots) and plays a role in regulating fibrinolysis.13 If the innate immune system fails to resolve the infection, then the cells of this system will initiate the adaptive immune system.8 IL-18 helps TH1 induction.11 The two T helper cells regulate each …show more content…
IgA is responsible for defending against microorganisms at body surfaces that are lined with mucous membranes such as the eyes, nose, and GI tract.16 IgA is found in the bloodstream, in secretions made by mucous membranes (in tears and saliva), and in the colostrum.16 IgM is found in the bloodstream and is made when an antigen is encountered for the very first time.16 When IgM attaches to the antigen, the complement system is activated, allowing the microorganism to be easier to engulf.16 IgE is responsible for triggering allergic reactions.16 These antibodies bind to basophils and mast cells.16 When these units come in contact with allergens, they release substances such as histamines to cause inflammation and damage nearby tissues.16 IgE is found in small amounts in the bloodstream and digestive system.16 Individuals with allergic disorders have higher amounts of IgE.16 IgD is found on the surface of most B cells but their exact function is unknown.17 IgG is found in the bloodstream and tissues.16 IgG is produced when the body is exposed to an antigen a second time and is responsible for protection against microorganisms such as bacteria, fungi, and viruses.16 There are four subclasses of human IgG: IgG1, IgG2, IgG3, and IgG4.3 Since IgG1, IgG3, IgG4 can cross the placenta, they are responsible for protecting the developing fetus .3 IgG3 also plays a role in complement activation and helps with opsonization.3 IgA and IgM exist as dimers and pentamers,
Infection occurs when pathogens are able to cross the epithelial surfaces of the body and overcome the host’s innate immune system.8 When the pathogen enters the tissues, they are first recognized by macrophages.8 MCP1 promotes monocytes to become macrophages in the tissues.9 Neutrophils will also be recruited to the site of infection.8 IL-8 promotes neutrophils to exit the bloodstream and enter nearby tissues.9 During an infection, inflammation serves to fight the infection.8 TNF-alpha induces a local inflammatory response which helps control infections .9 A number of inflammatory responses such as pain, swelling, heat, and redness, can occur at the infection site.8 CRP is secreted in response to inflammation and helps activate complement, binds to Fc receptors, and enhances phagocytosis.10 IL-6 increases body temperature and initiates acute phase response.9 IL-1-Beta induces fever, T-cell & macrophage activation.11 Also during inflammation, the surfaces of blood vessel endothelium express cell-adhesion molecules known as ICAM- 1 and ICAM-2.9 If there is tissue damage, fibrinogen helps form blood clots to stop bleeding.12 PAI1 is the main inhibitor of plasminogen activators (inhibits the breakdown of blood clots) and plays a role in regulating fibrinolysis.13 If the innate immune system fails to resolve the infection, then the cells of this system will initiate the adaptive immune system.8 IL-18 helps TH1 induction.11 The two T helper cells regulate each …show more content…
IgA is responsible for defending against microorganisms at body surfaces that are lined with mucous membranes such as the eyes, nose, and GI tract.16 IgA is found in the bloodstream, in secretions made by mucous membranes (in tears and saliva), and in the colostrum.16 IgM is found in the bloodstream and is made when an antigen is encountered for the very first time.16 When IgM attaches to the antigen, the complement system is activated, allowing the microorganism to be easier to engulf.16 IgE is responsible for triggering allergic reactions.16 These antibodies bind to basophils and mast cells.16 When these units come in contact with allergens, they release substances such as histamines to cause inflammation and damage nearby tissues.16 IgE is found in small amounts in the bloodstream and digestive system.16 Individuals with allergic disorders have higher amounts of IgE.16 IgD is found on the surface of most B cells but their exact function is unknown.17 IgG is found in the bloodstream and tissues.16 IgG is produced when the body is exposed to an antigen a second time and is responsible for protection against microorganisms such as bacteria, fungi, and viruses.16 There are four subclasses of human IgG: IgG1, IgG2, IgG3, and IgG4.3 Since IgG1, IgG3, IgG4 can cross the placenta, they are responsible for protecting the developing fetus .3 IgG3 also plays a role in complement activation and helps with opsonization.3 IgA and IgM exist as dimers and pentamers,