Chapter 35 Flashcards
Acquired (adaptive) immunity
Lymphocyte receptors provide pathogen-specific recognition. Defends against infection of body cells and fluids. Has 2 branches: 1) humoral immunity: extra cellular defense. The fight through the work of B cells. 2) cell mediated immunity: intracellular (example: virus)
Innate immunity
A form of defense common to all animals that is active immediately upon exposure to pathogens and that is the same whether or not the pathogen has been encountered previously.
Humoral immunity
B cell activation. Production of antibodies from plasma cells. Memory cells made. Defend.
Cell mediated immunity
T cell activation. Cytotoxic T cells- binds to and/or lyses (cuts) cells. Memory cells made. Defend.
Phagocytosis
A type of endocytosis in which large particulate substances or small organisms are taken up by a cell. It is carried out by some protists and by certain immune cells of animals (in mammals, mainly macrophages, neutrophils, and dendritic cells).
Barrier defenses
Okay
Neutrophil
The most abundant type of white blood cell. Neutrophils are phagocytic and tend to self-destruct as they destroy foreign invaders, limiting their life span to a few days.
Macrophage
A phagocytic cell present in many tissues that functions in innate immunity by destroying microbes and in acquired immunity as an antigen-presenting cell.
Natural killer cell
A type of white blood cell that can kill tumor cells and virus-infected cells as part of innate immunity.
Lymphocyte
A type of white blood cell that mediates immune responses. The two main classes are B cells and T cells.
T cells
The class of lymphocytes that mature in the thymus; they include both effector cells for the cell-mediated immune response and helper cells required for both branches of adaptive immunity.
B cells
The lymphocytes that complete their development in the bone marrow and become effector cells for the humoral immune response.
Antigen
A substance that elicits an immune response by binding to receptors of B cells, antibodies, or T cells.
Epitope
A small, accessible region of an antigen to which an antigen receptor or antibody binds; also called an antigenic determinant.
Antigen receptor
The general term for a surface protein, located on B cells and T cells, that binds to antigens, initiating adaptive immune responses. The antigen receptors on B cells are called B cell receptors, and the antigen receptors on T cells are called T cell receptors.
Plasma cell
The antibody-secreting effector cell of humoral immunity. Plasma cells arise from antigen-stimulated B cells.
Antibodies
A protein secreted by plasma cells (differentiated B cells) that binds to a particular antigen; also called immunoglobulin. All antibodies have the same Y-shaped structure and in their monomer form consist of two identical heavy chains and two identical light chains.
Helper T cell
A type of T cell that, when activated, secretes cytokines that promote the response of B cells (humoral response) and cytotoxic T cells (cell-mediated response) to antigens.
Clonal selection
The process by which an antigen selectively binds to and activates only those lymphocytes bearing receptors specific for the antigen. The selected lymphocytes proliferate and differentiate into a clone of effector cells and a clone of memory cells specific for the stimulating antigen.
Major histocompatibility complex (MHC) molecules
A host protein that functions in antigen presentation. Foreign MHC molecules on transplanted tissue can trigger T cell responses that may lead to rejection of the transplant. Genes in a group that make proteins that can present antigen fragments on outside of cells.
Cytotoxic T cell
A type of lymphocyte that, when activated, kills infected cells as well as certain cancer cells and transplanted cells.
Cell mediated immune response
The branch of adaptive immunity that involves the activation of cytotoxic T cells, which defend against infected cells.
Humoral immune response
The branch of adaptive immunity that involves the activation of B cells and that leads to the production of antibodies, which defend against bacteria and viruses in body fluids.
Active immunity
Long-lasting immunity conferred by the action of B cells and T cells and the resulting B and T memory cells specific for a pathogen. Active immunity can develop as a result of natural infection or immunization.
Passive immunity
Short-term immunity conferred by the transfer of antibodies, as occurs in the transfer of maternal antibodies to a fetus or nursing infant.
Allergen
An antigen that triggers an exaggerated immune response.
Autoimmune disease
An immunological disorder in which the immune system turns against self.
Antibodies part 2
Produced by B plasma cells
Primary response
Body is first exposed to antigen, lymphocyte is activated.
Secondary response
The same antigen is encountered at a later time. The immune response is now faster and of greater magnitude.
Class I MHC molecules
found on all nucleated cells. (put out a “help” sign)
Class II MHC molecules
found on macrophages, B cells, dendrites
Antigen receptor
The general term for a surface protein, located on B cells and T cells, that binds to antigens, initiating adaptive immune responses. The antigen receptors on B cells are called B cell receptors, and the antigen receptors on T cells are called T cell receptors.
Antigen presenting cell
A cell that upon ingesting pathogens or internalizing pathogen proteins generates peptide fragments that are bound by class II MHC molecules and subsequently displayed on the cell surface to T cells. Macrophages, dendritic cells, and B cells are the primary antigen-presenting cells.
Antigen
A substance that elicits an immune response by binding to receptors of B cells, antibodies, or T cells.
Cytotoxic T cell
A type of lymphocyte that, when activated, kills infected cells as well as certain cancer cells and transplanted cells. A bind to protein fragments displayed on class I MHC molecules - to kill cells.
Antigen recognition
- B cell receptors bind to intact antigens. Then clonal selection begins.
- T cell receptors bind antigens displayed by antigen presenting cells (APC) (have it inside) on their MHC’s. Then clonal selection begins.
Helper T cells
Bind to proteins displayed by class II MHC molecules
Helper T lymphocytes
Function in both humoral and cell mediated immunity. Stimulated by MHC class II. Binds to MHC, clonal selection, memory helper T and activated helper T are made. Activated helper T secretes cytokines (they are just a chemical message)
Function of antibodies
Antibodies function in three distinct ways. They bind directly to antigens, effectively coating the surface of the invader, in order to prevent pathogens from entering or damaging healthy body cells. Antibodies can also stimulate other parts of the immune system (e.g. complement proteins) to destroy the pathogens. And, antibodies can mark pathogens through a process called opsonization so that the pathogens can be identified and neutralized by other immune cells.
Inflammatory response
An innate immune defense triggered by physical injury or infection of tissue involving the release of substances that promote swelling, enhance the infiltration of white blood cells, and aid in tissue repair and destruction of invading pathogens.
Histamine
A substance released by mast cells that causes blood vessels to dilate and become more permeable in inflammatory and allergic responses.
Physical barrier defenses
The skin (also known as the epithelial surface) functions as a continuous, impassable barrier to potentially-infectious pathogens . The skin is considered the first defense of the innate immune system; it is the first of the nonspecific barrier defenses.
Cellular defenses (toll like receptor)
Cytotoxic T cells
Allergies
Allergic diseases and symptoms occur because of an active immune system that reacts to things that are usually harmless, such as pollens, pet dander or foods.
Describe inflammatory response
Inflammatory response: 1) tissue injury; release of chemical signals. Macrophages release chemicals and histamine is released by mast cells which cause step 2. 2) capillaries widen and become more permeable- increased blood flow causes redness, heat, swelling and delivers antimicrobial proteins to site. Phagocytes and leukocytes attracted.
Dendritic cell
Dendritic cells (DCs) are antigen-presenting cells (also known as accessory cells) of the mammalian immune system. Their main function is to process antigen material and present it on the cell surface to the T cells of the immune system. They act as messengers between the innate and the adaptive immune systems.
Leukocyte
A blood cell that functions in fighting infections; also called a white blood cell.
Plasma B cell
Produce and secrete large amounts of antibodies. Antibodies assist in destruction of microbes binds to them, and makes them easier targets for phagocytes.
