- 16 Sep 2015 16:09
#14600303
Immunology is the study of physiological mechanisms that defend the body from pathogens. Body develops cells dedicated to defense which form the immune system.
Adaptive immunity takes time to develop, while the innate immune system is active immediatly but is less specific and less flexible.
Not all microbes are harmful, some are even helpful. The immune system plays a role in controlling indigenous microflora.
Protective immunity is developed against a specific pathogen. This is the system utilized using vaccinations with attenuated or killed infectious agents.
430 BC Thucydides recognized that only those who had recovered from the plague could nurse the sick without becoming sick again.
15th century, chinese and turks used dried crusts from small pox pustules to induced immunity.
1796 Jenner realized milkmaids who contracted cowpox did not contract small pox. Tested theory on 8 year old boy. Bioethics panel outraged.
Opportunistic pathogens cause disease if the body's defenses are weakened or it get's into a part of the body it isn't native to.
Constant evolutionary struggle between immune system and pathogen, replication times favor the pathogen.
Bacteria
Salmonella enteritidis- food poisoning
Mycobacterium tuberculosis- tuberculosis
Staphylococcus aureas- flesh eating disease
Virus
Variola- small pox
influenza- flu
HIV- AIDS
Fungi
Epidermophyton floccosum- ringworm
Candida albicans- thrush, systemic candidaisis
Protozoa
Trypaosoma Brucei- sleeping sickness
Leishmania dovani- lechmaniasis
Plasmodium falciparum- malaria
Worms
ascaris lumbricoides- ascariasis
schistosoma manosoni- schistosomiasis
Over 1000 microbial species in the human gut, these bacteria typically cause no harm to the host. They are called commensal bacteria. These bacteria are also killed by antibiotics.
Physical barriers against infection: Skin, epithelial linings of the respiritory, gastrointestinal, and urogenital tracts. Mucosal surfaces most vulnerable to infection.
Mucosal surfaces are bathed in mucus; thick fluid containing glycoproteins, proteoglycans, and protective enzymes.
Lysozyme in tears and saliva, antibacterial.
Respiratory tract mucos constantly removed to clean material out.
Stomach, vagina, and skin acidic to prevent bacterial growth.
Defnins, proteins that poke holes in pathogens.
Innate immune response
Innate immune system is determined entirely by inherited genes. Consists of two parts. Recognition and recruitment of effect mechanisms (cells).
Complement: series of proteins that act to tag an invader for phagocytosis by other immune cells or by poking holes in the microbe by completing the complement cascade.
Inflammation: the process of responding to invaders. Resident efector cells respond by releasing cytokines which induce vasodilation and vascular permiability allowing proteins, fluid, and inflammatory cells to leave blood and enter tissue.
The innate defense system is the fast first line that produces acute inflamation and has some specificity for microbes, uses different receptors to recognize pathogens.
The adaptive immune system takes longer to develope (about a week) is highly specific to antigens, uses one type of receptor. Primary response to novel pathogen, secondary response to known pathogens.
The innate and adaptive immune system work together through direct cell contact and interactions with chemical mediators (cytokines and chemokines).
Many cells of the innate immune system are the same cells used by the adaptive immune system.
Adaptive immunity-lymphocyte selection and proliferation: A single lymphocyte will have a receptor with a single specificity. When a foreign epitope is recognized by the lymphocyte receptor the cell will proliferate.
Immune cell classes:
Lymphoid cells, 20-50% of white blood cells. T cells, B cells, and NK cells.
Mononuclear phagocytes: Monocytes that circulate in blood, Macrophages.
Granulocytic cells: Neutrophils, Eosinophils, and basophiles.
Dendritic cells: main function is the presentation of antigen to T cells.
Hematophoiesis: generation of blood cells. Red blood cells, white blood cells, megakaryocytes.
Origionate from pluripotent hematopoitic stem cells whose progeny differentiate under the influence of various hematopoietic growth factors.
Hematopoetic stem cells differentiate into three lineages:
Lymphoid lineage- NK cells, T cells, adn B cells.
Myeloid lineage- Macrophages, dendritic cells, granulocytes, and mast cells.
Erythroid lineage- erythroblasts (red blood cells), Megakaryocyte (platelets)
Most abundant leukocyte is the neutrophils, followed by the lymphocytes.
Leukocytes- general term for white blood cells.
Lymphocytes, class of white blood cells that breaks down into small and large. Small lymphocytes are adaptive immune cells (B calls and T cells). Large granular lymphocytes, Natural Killer cells, innate immune cell.
Naive lymphcytes are samll lymphocytes that have not interacted with antigens.
Lymphoblasts are lymphocytes that have interacted with antigen and proliferate. Differentiate into effector cells and memory cells.
Effector cells eliminate antigen, Plasma B cells secrete antibody, cytokine producing T helper cells (CD4 cell), T cytotoxic cells (CD8 cell).
Natural Killer cells kill human cells that are infected with virus'.
Neutrophils are phagocytic cells.
NK cells are found throughout tissues but mainly in circulation. Secretes cytokins with prevent viral replication and activate T cell mediated immunity.
Neutrophils- effectors of innate immunity specialized in phagocytosis. Work in anaerobic conditions. Die at site of infection and create pus. contains toxic substances in intracellular granules.
Monocyte progenitors in the bone marrow differentiate into pro-monocytes which enter the blood where they differentiate into monocytes. Monocytes circulate in the blood for about 8 hours then mature and migrate into tissues and become macrophages. Phagocytic cells.
Dendritic cells activate T cells. Mast cells specialized in fighting parasites and are the main cause of allergies.
Dendritic cells are so called because of their many surface folds. Possess high levels of surface MHC class II molecules. Can also present MHC I. Process and present peptide antigens to T cells. Their role is to recognize antigens through innate receptors and present them to T cells.
Follicular dendritic cells Hold intact antigens in specialized areas of lymphoid tissues. Not related to regular dendritic cells. Found in germinal layers of the secondary lymphoid tissues.
Mast cells are found in the skin, connective tissue, and mucosal epithelial tissue of the respiritory and digestive tract. The origin of mast cells is uncertain but precursors differentiate in teh bone marrow and mature in tissues. When activated they degrandulate and releast pharmacological mediates like Histamine which causes inflammation.
Eosinophil, killing of antibody coated parasites through release of granules.
Basophil, controlling immune responses to parasites.
Eosinophils are granular leukocytes which stain with Eosin. They are present at low levels in circulation. Have some phagocytic activity but primarily involved in killing parasites. They usually bind to antibody coated parasites an release granules.
Basophils are granulocytes which stain with basica dyes and are present in extremely low numbers in circulation. Basophils and mast cells are very similar. both contain and release large electron dense granules during allergic responses.
Megakaryocytes in the bone marrow produce platelets. Function controlled by large number of cytokines, including thrombopoietin a glycoprotein hormone produced mainly by liver and kidney that regulates platelets.
Erythrocytes bind to immune complexes composed of antigen and antibody and carry these complexes to the liver where these are cleared by kupffer cells. Erythrocytes have an important immunological role in clearing immune complexes. Kupffer cells are phagocytic cells of the liver that line the hepatic sinusoids.
Neutorphiles are stored in bone marrow and released during infections.
Mononuclear phagocyte system, system of phagocytes located mainly in the organs and tissues.
Macrophage like cells in liver=kupffer cells
macrophage like cells in brain= microglia
Opsonization, way of making microbes more palatable to the phagocyte. Such as complement or antibody.
Adaptive immunity takes time to develop, while the innate immune system is active immediatly but is less specific and less flexible.
Not all microbes are harmful, some are even helpful. The immune system plays a role in controlling indigenous microflora.
Protective immunity is developed against a specific pathogen. This is the system utilized using vaccinations with attenuated or killed infectious agents.
430 BC Thucydides recognized that only those who had recovered from the plague could nurse the sick without becoming sick again.
15th century, chinese and turks used dried crusts from small pox pustules to induced immunity.
1796 Jenner realized milkmaids who contracted cowpox did not contract small pox. Tested theory on 8 year old boy. Bioethics panel outraged.
Opportunistic pathogens cause disease if the body's defenses are weakened or it get's into a part of the body it isn't native to.
Constant evolutionary struggle between immune system and pathogen, replication times favor the pathogen.
Bacteria
Salmonella enteritidis- food poisoning
Mycobacterium tuberculosis- tuberculosis
Staphylococcus aureas- flesh eating disease
Virus
Variola- small pox
influenza- flu
HIV- AIDS
Fungi
Epidermophyton floccosum- ringworm
Candida albicans- thrush, systemic candidaisis
Protozoa
Trypaosoma Brucei- sleeping sickness
Leishmania dovani- lechmaniasis
Plasmodium falciparum- malaria
Worms
ascaris lumbricoides- ascariasis
schistosoma manosoni- schistosomiasis
Over 1000 microbial species in the human gut, these bacteria typically cause no harm to the host. They are called commensal bacteria. These bacteria are also killed by antibiotics.
Physical barriers against infection: Skin, epithelial linings of the respiritory, gastrointestinal, and urogenital tracts. Mucosal surfaces most vulnerable to infection.
Mucosal surfaces are bathed in mucus; thick fluid containing glycoproteins, proteoglycans, and protective enzymes.
Lysozyme in tears and saliva, antibacterial.
Respiratory tract mucos constantly removed to clean material out.
Stomach, vagina, and skin acidic to prevent bacterial growth.
Defnins, proteins that poke holes in pathogens.
Innate immune response
Innate immune system is determined entirely by inherited genes. Consists of two parts. Recognition and recruitment of effect mechanisms (cells).
Complement: series of proteins that act to tag an invader for phagocytosis by other immune cells or by poking holes in the microbe by completing the complement cascade.
Inflammation: the process of responding to invaders. Resident efector cells respond by releasing cytokines which induce vasodilation and vascular permiability allowing proteins, fluid, and inflammatory cells to leave blood and enter tissue.
The innate defense system is the fast first line that produces acute inflamation and has some specificity for microbes, uses different receptors to recognize pathogens.
The adaptive immune system takes longer to develope (about a week) is highly specific to antigens, uses one type of receptor. Primary response to novel pathogen, secondary response to known pathogens.
The innate and adaptive immune system work together through direct cell contact and interactions with chemical mediators (cytokines and chemokines).
Many cells of the innate immune system are the same cells used by the adaptive immune system.
Adaptive immunity-lymphocyte selection and proliferation: A single lymphocyte will have a receptor with a single specificity. When a foreign epitope is recognized by the lymphocyte receptor the cell will proliferate.
Immune cell classes:
Lymphoid cells, 20-50% of white blood cells. T cells, B cells, and NK cells.
Mononuclear phagocytes: Monocytes that circulate in blood, Macrophages.
Granulocytic cells: Neutrophils, Eosinophils, and basophiles.
Dendritic cells: main function is the presentation of antigen to T cells.
Hematophoiesis: generation of blood cells. Red blood cells, white blood cells, megakaryocytes.
Origionate from pluripotent hematopoitic stem cells whose progeny differentiate under the influence of various hematopoietic growth factors.
Hematopoetic stem cells differentiate into three lineages:
Lymphoid lineage- NK cells, T cells, adn B cells.
Myeloid lineage- Macrophages, dendritic cells, granulocytes, and mast cells.
Erythroid lineage- erythroblasts (red blood cells), Megakaryocyte (platelets)
Most abundant leukocyte is the neutrophils, followed by the lymphocytes.
Leukocytes- general term for white blood cells.
Lymphocytes, class of white blood cells that breaks down into small and large. Small lymphocytes are adaptive immune cells (B calls and T cells). Large granular lymphocytes, Natural Killer cells, innate immune cell.
Naive lymphcytes are samll lymphocytes that have not interacted with antigens.
Lymphoblasts are lymphocytes that have interacted with antigen and proliferate. Differentiate into effector cells and memory cells.
Effector cells eliminate antigen, Plasma B cells secrete antibody, cytokine producing T helper cells (CD4 cell), T cytotoxic cells (CD8 cell).
Natural Killer cells kill human cells that are infected with virus'.
Neutrophils are phagocytic cells.
NK cells are found throughout tissues but mainly in circulation. Secretes cytokins with prevent viral replication and activate T cell mediated immunity.
Neutrophils- effectors of innate immunity specialized in phagocytosis. Work in anaerobic conditions. Die at site of infection and create pus. contains toxic substances in intracellular granules.
Monocyte progenitors in the bone marrow differentiate into pro-monocytes which enter the blood where they differentiate into monocytes. Monocytes circulate in the blood for about 8 hours then mature and migrate into tissues and become macrophages. Phagocytic cells.
Dendritic cells activate T cells. Mast cells specialized in fighting parasites and are the main cause of allergies.
Dendritic cells are so called because of their many surface folds. Possess high levels of surface MHC class II molecules. Can also present MHC I. Process and present peptide antigens to T cells. Their role is to recognize antigens through innate receptors and present them to T cells.
Follicular dendritic cells Hold intact antigens in specialized areas of lymphoid tissues. Not related to regular dendritic cells. Found in germinal layers of the secondary lymphoid tissues.
Mast cells are found in the skin, connective tissue, and mucosal epithelial tissue of the respiritory and digestive tract. The origin of mast cells is uncertain but precursors differentiate in teh bone marrow and mature in tissues. When activated they degrandulate and releast pharmacological mediates like Histamine which causes inflammation.
Eosinophil, killing of antibody coated parasites through release of granules.
Basophil, controlling immune responses to parasites.
Eosinophils are granular leukocytes which stain with Eosin. They are present at low levels in circulation. Have some phagocytic activity but primarily involved in killing parasites. They usually bind to antibody coated parasites an release granules.
Basophils are granulocytes which stain with basica dyes and are present in extremely low numbers in circulation. Basophils and mast cells are very similar. both contain and release large electron dense granules during allergic responses.
Megakaryocytes in the bone marrow produce platelets. Function controlled by large number of cytokines, including thrombopoietin a glycoprotein hormone produced mainly by liver and kidney that regulates platelets.
Erythrocytes bind to immune complexes composed of antigen and antibody and carry these complexes to the liver where these are cleared by kupffer cells. Erythrocytes have an important immunological role in clearing immune complexes. Kupffer cells are phagocytic cells of the liver that line the hepatic sinusoids.
Neutorphiles are stored in bone marrow and released during infections.
Mononuclear phagocyte system, system of phagocytes located mainly in the organs and tissues.
Macrophage like cells in liver=kupffer cells
macrophage like cells in brain= microglia
Opsonization, way of making microbes more palatable to the phagocyte. Such as complement or antibody.
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