Flashcards in this deck (112)

• The main functions of the immune system include protecting from infection and playing a role in many aspects of health and disease.
  immune_system functions
• The two major arms of the immune response are innate immunity and adaptive immunity.
  immune_system innate adaptive
• The innate immune system responds rapidly using germline encoded immune receptors that recognize broad classes of pathogens.
  innate_immunity immune_receptors
• The adaptive immune system responds more slowly but with higher specificity and has memory capabilities.
  adaptive_immunity specificity
• The major cell types of innate immunity include macrophages, neutrophils, and natural killer cells.
  innate_immunity cell_types
• The major cell types of adaptive immunity include T cells and B cells.
  adaptive_immunity cell_types
• Cellular immunity primarily removes intracellular pathogens while humoral immunity targets extracellular pathogens.
  cellular_immunity humoral_immunity
• Cluster of differentiation (CD) markers are used to identify specific cell types in the immune system, such as CD4 for T helper cells and CD8 for cytotoxic T cells.
  cd_markers immune_system cell_types
• The immune system distinguishes self from non-self using innate and adaptive immune responses.
  self_vs_non-self immune_system
• The primary role of the immune system is to protect from infection and also to defend against tumors.
  immune_system infection tumors
• Inappropriate immune responses can lead to conditions such as autoimmunity and allergies.
  immune_response autoimmunity allergies
• The immune system plays a role in tissue regeneration and scarring.
  immune_system tissue_regeneration scarring
• A successful immune response includes features such as recognition of pathogens, activation of immune cells, and elimination of pathogens.
  immune_response features
• The immune response to a pathogen involves the following steps: 1) Recognition of a pathogen; 2) Determining the type of pathogen; 3) Elimination of the pathogen; 4) Development of immune memory; and 5) Avoiding damage to self-tissues.
  immunology immune_response
• The immune system must defend the body from infection while maintaining tolerance to self and to commensal organisms.
  immunology tolerance
• The immune system is organized into two major arms: the innate immune response and the adaptive immune response.
  immunology immune_system
• Key cell types of the innate immune response include myeloid cells, natural killer cells, and others such as macrophages and neutrophils.
  immunology innate_immunity
• The adaptive immune response is characterized by B and T lymphocytes.
  immunology adaptive_immunity
• B lymphocytes produce antibodies that block infection and eliminate extracellular pathogens.
  immunology b_lymphocytes
• T lymphocytes are responsible for eradicating intracellular pathogens.
  immunology t_lymphocytes
• Innate immunity includes immediate defense mechanisms such as mechanical barriers, chemical barriers, and biological barriers.
  immunology innate_immunity
• The innate immune system recognizes broad categories of pathogens through germline-encoded innate immune receptors.
  immunology innate_immunity
• Adaptive immunity generates pathogen-specific immunity through specialized antigen receptors on lymphocytes.
  immunology adaptive_immunity
• The specialized antigen receptors of B lymphocytes can be secreted as antibodies.
  immunology b_lymphocytes
• The diagram illustrates the principal components of innate and adaptive immunity over time after infection, showing that innate immunity acts within hours while adaptive immunity develops over days.
  immunology immune_response diagram
• The innate immune response includes cells such as phagocytes and NK cells.
  immunology innate_immunity
• Mechanical barriers in innate immunity include skin and mucus.
  immunology innate_immunity
• Chemical barriers in innate immunity include enzymes like lysozyme and antimicrobial proteins such as beta-defensins.
  immunology innate_immunity
• The process of recognizing a pathogen in the immune response is known as pathogen recognition.
  immunology pathogen_recognition
• The elimination of a pathogen involves determining the appropriate response.
  immunology pathogen_elimination
• The development of immune memory leads to a faster and more robust response upon re-exposure to the same pathogen.
  immunology immune_memory
• The receptor of T lymphocytes is the T cell receptor.
  immunology t_lymphocytes
• Humoral immunity involves B lymphocytes that secrete antibodies to eliminate extracellular microbes.
  immunology humoral_immunity
• Cell-mediated immunity involves T lymphocytes that can kill infected cells and eliminate reservoirs of infection.
  immunology cell-mediated_immunity
• The adaptive immune response has a noticeable lag phase to initiation, beginning four to seven days after pathogen exposure.
  immunology adaptive_immune_response
• Adaptive immune responses are highly antigen-specific and have memory capabilities for quicker defense upon re-exposure to the same pathogen.
  immunology adaptive_immune_response
• Innate immune cells do not have the same memory capability as adaptive immune cells.
  immunology innate_immunity
• In humoral immunity, B lymphocytes secrete antibodies that eliminate extracellular microbes.
  immunology humoral_immunity
• In cell-mediated immunity, some T lymphocytes secrete cytokines that recruit and activate phagocytes.
  immunology cell-mediated_immunity
• Cytotoxic T lymphocytes (CTLs) kill infected cells and eliminate reservoirs of infection.
  immunology cytotoxic_t_lymphocytes
• Phagocytes can ingest and destroy pathogens such as Borrelia burgdorferi and Salmonella typhi.
  immunology pathogens
• Humoral immunity refers to soluble substances found in blood and other body fluids.
  immunology humoral_immunity
• Antibodies secreted by B lymphocytes bind to microbes, preventing further dissemination and enhancing microbial uptake by phagocytes.
  immunology antibodies
• The immune system uses both cells and secreted factors to defend the body.
  immunology immune_system
• Cellular immunity refers to cells, while humoral immunity refers to soluble immune factors like antibodies.
  immunology cellular_immunity
• The immune mechanisms that effectively clear Borrelia burgdorferi may not be the same as those effective against Salmonella typhi.
  immunology pathogens
• Phagocytes can ingest and destroy pathogens they encounter in body fluids.
  immunology phagocytes
• The comparison of humoral and cell-mediated immunity shows that humoral immunity involves B lymphocytes and secreted antibodies, while cell-mediated immunity involves T lymphocytes and macrophages.
  immunology comparison humoral_immunity cell-mediated_immunity
• The principal function of antigen presenting cells (APCs) is to engulf pathogens and present digested pieces to alert and recruit other immune cells. Examples of APCs include macrophages, B cells, and dendritic cells.
  immune_system apcs
• Antigen-specific lymphocytes include B and T cells, which mediate specific recognition of pathogens. Upon encountering their specific antigen, they undergo clonal proliferation and differentiate into specialized subtypes such as effector cells and memory cells.
  immune_system lymphocytes
• Effector cells carry out the functions of the immune response and include macrophages, granulocytes, and T cells. These cells can mediate the removal of pathogens without further differentiation.
  immune_system effector_cells
• B lymphocytes are mediators of humoral immunity, while T lymphocytes are mediators of cell-mediated immunity.
  immune_system lymphocytes
• Dendritic cells initiate T cell responses, while macrophages are involved in the effector phase of cell-mediated immunity.
  immune_system apcs
• Granulocytes include neutrophils, basophils, and eosinophils, which phagocytose pathogens and mediate inflammation.
  immune_system granulocytes
• Mast cells regulate blood vessel dilation and mediate inflammation.
  immune_system mast_cells
• Natural Killer (NK) cells destroy virally infected or tumorigenic cells as part of the innate immune response.
  immune_system nk_cells
• B lymphocytes produce antibodies (immunoglobulins) that are specialized for each pathogen and found in the blood as soluble proteins.
  immune_system b_lymphocytes
• T lymphocytes recognize infected or transformed cells and are responsible for their destruction and elimination from the body.
  immune_system t_lymphocytes
• The table detailing cell types and their principal functions in the immune system includes lymphocytes (B and T cells), antigen-presenting cells (dendritic cells, macrophages), and effector cells (T lymphocytes, macrophages, granulocytes). See image:
  immune_system cell_types
• Immune cells can be identified by their cell surface molecules called CD Markers. These are receptors or proteins found on the plasma membrane.
  immunology cells
• All B lymphocytes express the cell surface receptors CD19 and CD20.
  immunology b_cells
• All T cells express CD3.
  immunology t_cells
• CD3+ T cells can be divided into two subsets: CD4 helper T cells and CD8 cytotoxic T cells.
  immunology t_cells
• CD4 helper T cells provide help signals to activate other immune subsets, while CD8 cytotoxic T cells kill infected or cancerous cells.
  immunology t_cells
• Clinical diagnostics use the CD marker system to identify a patient's type of leukemia or lymphoma cell.
  immunology diagnostics
• Major identifying cell surface markers for immune cells include CD34 and c-kit for Hematopoietic stem cells (HSC).
  immunology cell_markers
• B cells express the surface markers CD19 and CD20.
  immunology b_cells
• T cells express the surface marker CD3.
  immunology t_cells
• NK cells express the surface markers CD16 and CD56.
  immunology nk_cells
• Antigens are defined as an organism, molecule, or part of a molecule that is recognized by the immune system.
  immunology antigens
• Antigens can be simple or complex, protein or carbohydrate.
  immunology antigens
• The immune system can recognize altered self, which refers to changes in the body's cells after infection or malignant transformation.
  immunology self_recognition
• Altered self antigens may be mutated gene products or normal proteins expressed at higher levels due to aberrant regulation.
  immunology altered_self
• Microorganisms bear repeating patterns of molecular structure on their surface, known as PAMPs or DAMPs.
  immunology patterns
• PAMPs are specific targets of the immune system and include structures like the cell walls of Gram-positive and Gram-negative bacteria.
  immunology bacteria
• Bacterial flagella are made up of repetitive protein subunits.
  immunology bacteria
• Many viruses express double-stranded RNA as part of their life cycle.
  immunology viruses
• Innate immune cells use receptors that are germline encoded to recognize pathogen-associated antigens.
  immunology innate_immunity
• B and T cells express receptors generated through DNA recombination.
  immunology adaptive_immunity
• The process of DNA rearrangement can generate up to 10^{17} unique receptors.
  immunology receptors
• Each B or T cell expresses only one type of receptor, which is always on the cell surface, although B cells can secrete their receptors in the form of antibodies.
  immunology b_cells
• Illustration shows an antigen with antibodies bound to its surface.
  immunology antigens
• Table listing major identifying cell surface markers includes Hematopoietic stem cell, B cell, T cell, and NK cell with their corresponding CD markers.
  immunology cell_markers
• The two main types of immunity are innate immunity and adaptive immunity.
  immunology immune_system
• Innate immunity recognizes structures shared by classes of microbes known as PAMPs.
  immunology innate_immunity
• Adaptive immunity recognizes specific structural details of microbial molecules called antigens.
  immunology adaptive_immunity
• The receptors used in innate immunity are located in the plasma membrane, endosomal membrane, and cytosol.
  immunology receptors
• The receptors in adaptive immunity are located only in the plasma membrane.
  immunology adaptive_immunity
• Innate immunity has about 100 different types of invariant receptors, while adaptive immunity has only 2 types of receptors (Ig and TCR).
  immunology receptors
• The number of unique antigens recognized by the adaptive immune system is estimated to be greater than 10^7.
  immunology adaptive_immunity
• In the immune response, clonal expansion can lead to about 10^6 microbe-specific T cells.
  immunology immune_response
• The contraction phase of the immune response results in about 10^4 T cells remaining after the response.
  immunology immune_response
• The early innate defense relies on invariant, germline-encoded receptors recognizing common features of pathogens.
  immunology innate_immunity
• Adaptive immunity provides enhanced protection against reinfection by recognizing a particular pathogen.
  immunology adaptive_immunity
• The classic cadence of the immune response shows the number of microbe-specific T cells over time, indicating phases of clonal expansion and contraction.
  immunology immune_response
• The graph depicting the classic cadence of the immune response shows the number of CD8+ T cells and CD4+ T cells over days after infection.
  immunology immune_response
• The innate immune system is crucially important but has limitations as it can be overcome by many pathogens.
  immunology innate_immunity
• Adaptive immunity is characterized by the formation of memory cells after an initial response to a pathogen.
  immunology adaptive_immunity
• The discrimination of self and nonself in innate immunity is based on the recognition of healthy host cells that do not express certain molecules.
  immunology self_nonself_discrimination
• In adaptive immunity, self-reactive lymphocytes are eliminated or inactivated to avoid autoimmunity.
  immunology adaptive_immunity
• The genes encoding receptors in innate immunity are germline encoded and present in all cells.
  immunology receptors
• In adaptive immunity, receptors are formed by somatic recombination of gene segments only in B and T cells.
  immunology receptors
• The table comparing innate and adaptive immunity features highlights differences in specificity, microbial molecules recognized, receptors, distribution, genes, and self-non-self discrimination. See the comparison table for details:
  immunology innate_vs_adaptive_immunity
• The innate immune response fails to eliminate a new infection, leading to activated antigen presenting cells being delivered to the draining lymph nodes.
  immune_system innate_immunity
• When a recirculating lymphocyte encounters its corresponding antigen, it is induced to proliferate and differentiate into effector B or T lymphocytes.
  immune_system adaptive_immunity
• A subset of proliferating lymphocytes differentiates into memory cells, which are ready to respond rapidly to the same pathogen if encountered again.
  immune_system memory_cells
• After infection clears, antigen-specific lymphocytes gradually decrease from its peak in a phase called resolution phase.
  immune_system resolution_phase
• Following resolution, antigen-specific lymphocytes are sustained at a level that is slightly higher than prior to infection, contributing to immunological memory.
  immune_system immunological_memory
• The immune system defends the body against infection, with the innate immune system acting quickly but lacking the ability to recognize certain pathogens.
  immune_system innate_immunity
• Adaptive immunity is based on clonal selection from a repertoire of lymphocytes bearing highly diverse antigen-specific receptors.
  immune_system adaptive_immunity
• Host defense requires different recognition systems and a wide variety of effector mechanisms to seek out and destroy diverse pathogens.
  immune_system host_defense
• The innate immune system provides non-specific protective immunity, while adaptive immunity provides specific protective immunity that prevents reinfection.
  immune_system immunity_types