The immune system is responsible to protect the body from foreign pathogens via a barrier. When pathogen exposure happened the barrier which is physical like skin and mucus and mechanical like fluid flow and cilia and also chemical like pH, antibodies and enzymes. When barrier fails there is the innate immune response which is rapid and nonspecific like the cell that includes macrophages, neutrophils, dendrites, basophils, eosinophils, and a natural killer.In chemical immune response with interferons and complements. Then, antigen presenting cells facilitate to the innate immune response and create adaptive immune response with are specific with memory and slow; cell-mediated responses like B lymphocytes with plasma cell, T lymphocytes with cytotoxic, helper, and regulatory T cells that leads to destroy or suppress the pathogen so does the antibody-mediated responses via chemical reaction like antibodies.
The immune system splits into lymphoid tissue and immune cells. Lymphoid tissues include primary lymphoid tissues that immune cells which are (basophil/ mast cell, eosinophil, neutrophil, macrophage, monocyte, dendrites cells, and lymphocytes) form and mature in the thymus gland and bone marrow which make most blood cells. The secondary lymphoid tissue activates mature immune cells; encapsulated in spleen and lymph nodes and unencapsulated which is diffused in tonsils and GALT. Immune cells like basophils and mast cells have rare WBC in blood and the main function is releasing chemicals that fix allergies and inflammation response. Eosinophils have few percentages of WBC in blood and its main function to kill invaders such as parasites. Neutrophils have 50 to 70 percent of WBC in blood and they form bands and their main function is also to kill invaders. Monocytes and macrophages have the small percentage of WBC in blood and known as mononuclear phagocyte system that has histiocytes, kupffer cells, microglia, osteoclast, and reticuloendothelial cells and its primary function is to absorb and kill invaders with antigen presentation. Dendrites cells don’t have WBC in blood and know as Langerhans cells and its main function is to determine pathogens and activate other immune cells via antigen presentation. Lymphocytes (B L plasma and memory cell, T L L cytotoxin T, helper T, and natural killer cells )and plasma cells have 20 to 35 percent of WBC in blood and their main function is detected specific reactions to invader and creation of antibodies.
How immune cells made. The development starts with pluripotent hematopoietic stem cells that form committed progenitor cells that form mast cell, eosinophil, basophil, neutrophil, dendritic cell, monocyte that form macrophage, megakaryocyte that form platelets, reticulocyte that forms erythrocyte. The lymphocyte stem cells form lymphocyte B which forms plasma cell. They are also made in thymus and they form lymphocyte T. Also NK cell, Eosinophil, basophil, and neutrophil.
Creation of self-tolerance in primary lymphoid tissues where bone marrow and thymus gland and they put their receptors to bind to the self-antigen and die via apoptosis and those ones who don’t respond to self-antigen go into the cell and form clones.
Membrane attack complex making pores in pathogens via proteins that are complement and water with ions go into the pathogen cell via pores of the membrane attack complexes and cell lysis and swell.
The antibody has two chains one is light and the other one is heavy and they are both are connected with a disulfide bond. It starts with antigen binding site where it connects with chains and fab region and Fc region and in the middle, the hinge region let the movement of the arms. Antigen binding which has antibodies and they site on the arms
Barriers that are chemical, physical and mechanical. The epithelium is a physical barrier that protects the skin and mucous membrane. Glandular Secretions are chemical barriers that secrete mucus, antibodies, enzymes to kill pathogens. Stomach acidity is a chemical barrier that has low pH level that is in the stomach so it can kill pathogens that are consumed. Mechanical removal is responsible for removing pathogens physically via mucociliary escalator, tears, coughing, sneezing and GI ability to move.
Phagocytosis take the pathogens right into the immune cell it has absorbed pathogen and lysosomal enzymes absorb pathogen and making antigenic fragments. Primary phagocytes are the neutrophil, dendrites cell, and macrophages.
Antigen presenting cells includes antigenic fragment.
Lymphocyte clones are specific to one antigen and can be 1 clone,2 or 3.
T lymphocytes include NK cell that is responsible for killing the virus-infected cells and antibody tagged pathogens. B cells that activate to effector cells that divide into a memory cell that starts the constant secondary response and plasma cells that secrete antibodies and creates Lon lived plasma cells that secrets low level of antibody for ongoing immunity. T cells that are divided into cytotoxic T cell that kills cell showing as MHC antigen complexes. Helper T cells that activate other lymphocytes and Regulatory T cells that don’t let a lot of immune response via causing other lymphocytes.
Primary immune responses antigen can make the clonal expansion, B lymphocytes reproduce and B lymphocytes converts into plasma cells and short-lived effector cells implement the immediate response. Memory B cell with long-lived plasma cells makes the immunologic memory. Secondary immune responses are when memory B cell is exposed themselves once again to the right antigen and then the clone become wider and with a more faster way where they make more effector and memory cells.
Antibody function: Antigen clumping with bacteria and disable bacterial toxins and it acts like optimism to tag antigens for phagocytes where encapsulated bacteria are layered with antibody and antibodies bind to phagocyte receptors that activate phagocytosis. Then it activates degranulation where antibody depends on cell-mediated cytotoxicity. NK cell kills pathogen and mast cell releases histamine and cytokines which happens in activated complements and Activate B lymphocytes where memory cell and plasma cells secrete antibodies.
T lymphocyte activation starts when cell binds to T lymphocyte between MHC receptor and T cell receptor then signal transduction triggers T lymphocyte where Helper T cells bind to MCH II antigen presenting cells and release cytokines that trigger other immune cells. Then, T lymphocytes activate cytotoxic T cell that destroyed specific cells via perforin and granzymes.
Immune responses to extracellular bacteria that can cause inflammation when it enters. Bacteria then activates complement proteins that act like opsonins and coat and it makes membrane attack complex the creates lyses and activates mast cells that secrete chemotaxis that attacks circulating leukocytes and mast cells secrete histamine that increases permeability to the capillary. Complement proteins also present antigen to The cells that activate B lymphocytes and convert into plasma cells. Bacteria absorbed and disable via phagocytes and activate B lymphocytes convert to plasma cell that secretes antibodies. Acute phase proteins also act as opposing made from plasma proteins in capillaries.
Immune responses to viruses as antibodies act like that are opsonins that coating viral parts to make macrophages to be able to attack them better. They then digest the virus and insert viral antigens into the MHC II molecules into their membrane and they are triggered which let them secrete cytokines. The helper T cells activated by binding to a viral antigen on macrophages and when they are activated that initiate cytotoxic cell and B lymphocytes. When plasma cell created via active memory B lymphocytes making them make more antibodies. When cytotoxic T cells activated they attack and kill the cell that is infected.
When it exposed allergen absorbed via antigen presenting cell and they trigger helper T cell that activates B lymphocytes converting to plasma cell and then to the memory cell that then keeps the memory of that allergen that was first met. When it comes again the immune cells triggers faster and the reaction of the body as a result release histamine from mast cells, and cytokines.
ABO blood group: Blood type can be o and antigen on red blood cell makes no A or B antigen as a result antibodies in plasma are anti A and anti B. When blood type is A the antigen on red blood cell A antigen as a result antibodies in plasma are Anti – B. When blood type is B antigen on red blood cell is B antigen as a result antibodies in plasma is Anti-A. When blood type is AB antigen on red blood cell is A and B antigens as a result antibodies in plasma are known to A or B.
Chemical with immune system, nervous system and endocrine system: Pathogens connect with immune cells that connects with physical and emotional stress which is in the brain that interacts with the cytokines and neuropeptides between the immune system which then sends signals to the endocrine cells where hormones respond to the immune cells then from it the hormone connects with the target cells. The Brain connects with hormones and neuropeptide that interact with endocrine cells that send hormones to the target cells that was interacted with brain
CHAPTER 24 Figure 24