Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
72 Cards in this Set
- Front
- Back
|
Immunology |
Science focused on immune responses to foreign substances and how these responses are used to resist infection |
|
|
Innate Immunity |
- The body's built in ability to recognize and destroy pathogens or their products - Mediated by phagocytes - Occurs within hours after infection - Defends against all invaders equally - No increased induction upon subsequent exposures |
|
|
Phagocytes |
- Cells that can ingest, kill, and digest most microbial pathogens - Present antigens to lymphocytes |
|
|
Adaptive Immunity |
- The acquired ability to recognize and destroy a specific pathogen or its products - Responses are directed at unique pathogen molecules called antigens - Usually takes several days to develop |
|
|
Lymphocytes |
- Exclusive to the adaptive immune system - Specialized leukocytes - Circulated through blood and lymph but concentrated in lymph nodes and spleen - Interact with antigens - Two types: T and B cells |
|
|
Antigen |
- Bind specific receptors on the lymphocyte, triggering genes that promote lymphocyte multiplication and production of pathogen-specific proteins tat interact with the pathogen, marking it for destruction |
|
|
Stem Cells |
- Precursors that allow for the development of cells active in innate and adaptive immunity - Grow in the bone marrow - Can differentiate into any blood cell |
|
|
Lymph |
A fluid similar to blood that contains nucleated cells and proteins but lacks red blood cells |
|
|
Cytokines |
- Proteins that influence many aspects of immune cell differentiation |
|
|
Chmokines |
- Proteins that influence many aspects of immune cell differentiation |
|
|
Erythrocytes |
- Red blood cells - Non-nucleated - Function to carry oxygen from the lungs to the tissues - Comprise most of the total blood cells in human blood |
|
|
Leukocytes |
- Carry about 0.1% of the cells in blood - Nucleated - White blood cells - Include phagocytes (innate immune response) and lymphocytes (adaptive response) |
|
|
Plasma |
A liquid containing proteins and other solutes |
|
|
Serum |
- The fluid that remains when blood and plasma clots - Contains no cells or clotting proteins - Contains high concentration of proteins, including soluble immune proteins: antibodies |
|
|
Antibodies |
- Also called immunoglobulins - Soluble proteins produced by B cells and plasma cells in response to exposure to antigens - Interact with particular antigens - Generally do not directly kill the pathogen - May block interactions - Neutralize toxins - Have four polypeptide chains: 2 heavy and 2 light - Fab = antigen binding fragment |
|
|
Where in the circulatory system are leukocytes and solutes passed in between the blood and the lymphatic system? |
The capillary beds |
|
|
Lymph Nodes |
Organs that contain lymphocytes and phagocytes arranged to encounter microorganisms and antigens as they travel through the lymphatic circulation |
|
|
MALT |
- Mucosa-associated lymphoid tissue (MALT) - Part of the lymphatic system - Carries out both the innate and adaptive immune responses - Interacts with antigens and microorganisms that enter the body through mucous membranes, including those of the gut, the genitourinary tract, and bronchial tissues - Contains phagocytes and lymphocytes |
|
|
T Cells |
- Begin development in the bone marrow but mature in the thymus - Protect against intracellular pathogens such as viruses and certain bacteria through their TCR - Mediate production of antibodies - Interact with antigens - Specifically kill off targeted cells |
|
|
B Cells |
- Mature in bone marrow - Type of lymphocyte - Have antibodies on their surface - Precursors of antibody-producing plasma cells - Specialized APCs (antigen presenting cells) |
|
|
What are the primary lymphoid organs? |
The thymus and the bone marrow |
|
|
Myeloid Cells |
- Can be divided into two lineages: monocytes and granulocytes - Active in innate immunity - Derived from myeloid precursor cells |
|
|
Monocytes |
- Immature cells - Circulating precursors of macrophages and dendritic cells |
|
|
Granulocytes |
- Derived from myeloid precursors - Contain cytoplasmic inclusions, or granules, that can be visualized by staining - Granules contain toxins or enzymes that are released to kill target cells |
|
|
Antigen-Presenting Cells |
- Engulf, process, and present antigens to lymphocytes - Include macrophages and dendritic cells |
|
|
Macrophages |
- The first defines cells that interact with a pathogen - Abundant in many tissues, especially the spleen, lymph nodes, and MALT |
|
|
Neutrophils |
- Type of granulocyte - Central to innate immunity - Actively motile - Contains lysosomes |
|
|
Dendritic Cells |
- Phagocytes that specialize in presenting antigens to lymphocytes |
|
|
What are the secondary lymphoid organs? |
- Lymph nodes - MALT - Spleen - The sites where antigens interact with antigen-presenting phagocytes and lymphocytes to generate an adaptive immune response |
|
|
Degranulation |
- The release of granules - Can cause allergy symptoms and inflammation |
|
|
Mast Cells |
- A type of granulocyte - Derived from myeloid precursors - Capable of degranulation: the releasing of granules |
|
|
Plasma Cells |
- Antibody producers |
|
|
PAMPs |
- Pathogen- associated molecular patterns (PAMPs) - Consist of repeating subunits - Displayed by macromolecules inside and on the surface of pathogens - e.g., LPS, bacterial flagellin, lipoteichoic acids |
|
|
PRRs |
- Pattern recognition receptors (PRRs) - Molecules that interact directly with PAMPs - Characteristic of phagocytes - Each PRR interacts with a particular PAMP to activate the phagocyte to ingest and destroy the targeted pathogen by phagocytosis |
|
|
Primary Adaptive Immune Response |
- Generated after first exposure to an antigen - Stimulates growth and multiplication of antigen-reactive cells, creating clones, large umbers of identical antigen reactive cells - Clones confer long-term specific immunity |
|
|
TCRs |
- T cell receptors - The antigen-binding proteins of T cells - Membrane-spanning from cell surface to extracellular environment - Consists of two polypeptides, an alpha chain and a beta chain - Each polypeptide consists of several domains |
|
|
BCRs |
- B cell receptors (BCRs) - Cell-surface antibodies |
|
|
Secondary Adaptive Immune Response |
- Results as second exposure to the same antigen - Clones of antigen-reactive cells created in primary adaptive immune response are activated to generate a faster, stronger response - Products quickly target pathogen for destruction - Memory - |
|
|
Tolerance |
- The acquired inability to generate an immune response against self antigens - Ensures that adaptive immunity is directed to outside agents that pose genuine threats to the host and not to host proteins |
|
|
MHC |
- Major histocompatibility complex (MHC) - Proteins found on host cells surfaces - All cells present MHC I proteins - Required for T cell recognition |
|
|
MHC I |
- Displayed by all nucleated cells |
|
|
MHC II |
- Displayed by APCs (macrophages, dendritic cells, and B cells) |
|
|
Antigen Presentation |
1) APCs ingest bacteria, viruses, and other antigenic material by phagocytosis or through internalization of molecular antigens bound to BCR 2) APCs degrade antigens to small peptides 3) MHC proteins inside the APC bind the peptides derived from the ingested pathogens 4) MHC-embedded peptides are transported to the phagocyte surface where the complex is displayed 5) MHC I and MHC II proteins embedded with pathogen peptides are the targets for T cells |
|
|
Th1 Cells |
- T-helper cells - Interact with peptide-MHC II complexes on the surface of APCs - This interaction causes the Th cells to differentiate into one of two subsets that indirectly mediate immune reactions - Th1 cells interact with peptide-MHC II complexes on the surface of macrophages and produce cytokines that activate the macrophages - This ehances the phagocytosis of cells displaying the target peptide and causes the inflammatory reactions that limit the spread of infections |
|
|
Th2 Cells |
- T-helper cells - Use cytokines to stimulate antigen-reactive B cells to produce antibodies |
|
|
Tc Cells |
- T-cytotoxic cells - CD8 T cells - Recognize the peptide-MHC I complex on an infected cell - When Tc cells interact with the infected cell, they secrete proteins that kill the peptide-bearing infected cell - Granules within the cell are released at the contact site into the target cell to cause apoptosis |
|
|
Antibody Formation |
1) B cells binds antigens through interactions with BCR 2) The B cell is induced to ingest the antigen-containing pathogen by phagocytosis 3) Pathogen-derived peptide antigens are complexed with MHC II and are presented not eh surface oft eh B cell to Th2 cells 4) Th2 cells produce cytokines that stimulate B cells to grow and divide 5) Many B cells become plasma cells that produce soluble antibodies |
|
|
Neutralization |
The process by which specific serum antibodies can bind toxins such as tetanus, blocking the binding of the toxin to host cell receptors |
|
|
Opsonization |
- The enhancement of phagocytosis due to the deposition of antibody or complement on the surface of a pathogen or other antigen - The serum component acts as a bridge between microbes and specific receptors on phagocytes |
|
|
Complement |
- A group of proteins - Attach to pathogen surfaces, attracted by IgM or IgG antibodies bound to the pathogen - Can form a pore in the pathogen cytoplasmic membrane, directly lysing the pathogen, or - Can stimulate phagocytosis - Assemble in cascades - Three activation pathways: 1) classical - Initiated by antibody-antigen interaction 2) MB-lectin - Initiated by MBL binding to pathogen polysaccharide 3) alternative - Initiated by the attachment of alternative pathway proteins to C3b on the cell surface |
|
|
Natural Active Immunity |
Exposure to infection makes a person immune to further infection |
|
|
Natural Passive Immunity |
Passing on of antibodies from mother to fetus |
|
|
Artificial Active Immunity |
Product of immunization which are often attenuated toxins |
|
|
Artificial Passive Immunity |
- The product of giving someone a dose of antibodies - e.g., antibodies give to combat a rattle snake toxin or a rabid raccoon |
|
|
TLR |
- Toll-like receptor (TLR) - Recognizes a specific PAMP - TLR-2, a PRR on human phagocytes, interact with peptidoglycan, a PAMP present in the cell wall of nearly all bacteria. This activates phagocytes, targeting exposed peptidoglycan |
|
|
TCR V Domains |
- Variable domains of the polypeptide chains of the TCR - Dictates which antigen the TCR is able to bind to |
|
|
TCR C Domains |
- Constant domains of the polypeptide chains of the TCR |
|
|
What are the two kinds of adaptive immunity? |
1) Humoral (antibody-mediated) - Mediated by B cells 2) Cellular - The cells themselves target invaders specifically - Tc cells and natural killer cells |
|
|
Epitope |
The portion of an antigen that is recognized by an immunoglobulin or a T cell receptor |
|
|
Natural Killer Cells |
- Cytotoxic lymphocytes - Distinct from T cells and B cells - Resemble Tc cells in their ability to destroy cancer cells and cells infected with intracellular pathogens - Do not exhibit memory - Do not require prior exposure with the foreign cells - Use MHC I receptors to recognize MHC I proteins which deactivates the natural killer cells - Have complementary receptors for stress proteins exhibited by pathogen-infected cells |
|
|
Fab |
- Antigen-binding fragment of antibodies - Present in variable regions |
|
|
Somatic Recombination |
Gene splicing and rearrangements in the differentiating B cells during their development in the bone marrow |
|
|
Somatic Hypermutation |
The mutation of immunoglobulin genes at rates higher than those observed in other genes |
|
|
Clonal Selection |
Process by which specific cells within the large and dive B-cell pool are stimulated by antigens to reproduce and form B-cell clones (with the same genetic information 1) Self-reactive cells are eliminated at an early stage in development (via apoptosis) 2) Release from primary development site and exposure to its antigen causes proliferation and clone formation 3) All clonal cells react with the same Ag that stimulated its formation |
|
|
Anergy |
The inability to produce an immune response to specific antigens due to neutralization of effector cells |
|
|
CD4 Coreceptor |
A protein found exclusively on Th cells that interacts with MHC II on an antigen-presenting cell |
|
|
CD8 Coreceptor |
A protein found exclusively on Tc cells that interacts with MHC I on a target cell |
|
|
Signal 2 of T Cell Receptor Activation |
- B7 (CD80) protein on surface of an APC binding to CD28 receptor on T cell |
|
|
B Cell Receptor Activation |
1) Antigen binding and cross-linking of surface immunoglobulin 2) B cell is stimulated to produce CD40 and express it on the cell surface 3) The B cell process the antigen an presents it to a Th2 cell via MHC II |
|
|
Alternative Complement Activation Pathway |
- Initiated in response to bacterial and some fungal molecules with repetitive structures - LPS activates C3 to cleave into C3a an C3b - Factor B interacts with bound C3b and is in turn cleaved by Factor D into Ba and Bb - C3bBb acts the C3 converts in this pathway |
|
|
Classical Complement Activation Pathway |
- Mainly involved in antibody mediated recognition (IgG and IgM) - Also in response to some microbial compounds (e.g., LPS) - C4 an dC2 cleaved into C4a and C4b and C2a and C2b - C4b2a is a C3 converts (this cleaves C3 into C3a and C3b) |
|
|
MB-Lectin Complement Activation Pathway |
- Mannose binding protein (MBP) produced when macrophages ingest viruses, bacteria, and other foreign material - Mannose major component of bacterial cell wall, some virus envelopes and antigen-antibody complex - This can act as an opsonin, but also forms a C3 converts via MASP - MBL or ficolin bind surface carbohydrates - This activates MASP which cleaves C4 an dC2 - C4b2a is the C3 converts |
