Adaptive Immunity (7.3) Flashcards
Describe adaptive immunity
Immune response that is specific to a particular antigen
State the 2 distinguishing features of the adaptive immune response
- specificity
2. immunological memory
Describe specificity as a distinguishing feature of the adaptive immune response
Ability to recognise and respond exclusively to specific antigens
Describe immunological memory as a distinguishing feature of the adaptive immune response
Ability of cells of the adaptive immune system to ‘remember’ antigens after primary exposure
State what may occur as a result of immunological memory in the adaptive immune response if the ‘same’ pathogen is encountered again
Easily mount a large and rapid response to antigen
Provide the name of the cells most crucial to the adaptive immune response
Lymphocytes
State what each lymphocyte has for each antigen
Different receptor
State whether or not lymphocytes are able to undergo proliferation
Yes.
State the 2 classifications of lymphocytes
- B lymphocytes
2. T lymphocytes
State whether or not lymphocytes can undergo clonal selection
Yes.
State the 2 classifications of lymphocytes
- B lymphocytes
2. T lymphocytes
State where B lymphocytes develop
Bone marrow
State where T lymphocytes develop
Bone marrow
State where B lymphocytes complete their maturation
Peripheral lymphoid organs and tissues
State where T lymphocytes differentiate
Thymus
Describe cell-mediated immunity
Immune response that is mediated by T lymphocytes
State what cell has a heavy involvement in humoral immunity
B lymphocytes
State what B lymphocytes produce throughout the humoral immune response
Specific antibodies against foreign antigens
State where B lymphocytes release antibodies throughout the humoral immune response
Blood and lymphatic vessels
Provide an alternative term for bodily fluids
Humoral
Describe differentiation
Modification of the structure and function of a cell that occurs during its’ development
State approximately how many B lymphocytes may be circling through the blood of a human being
Billions
Provide the term used to describe mature lymphocytes that have not been activated by an antigen
Naive
Describe naive
Mature lymphocytes that have not been activated by an antigen
State what occurs when a B lymphocyte meets and binds to a specific antigen
B lymphocyte is triggered/activated
State what occurs when a B lymphocyte is activated in the humoral immune response
B cell differentiates and proliferates
State what cytokines released by helper T lymphocytes are important for
Activation of B lymphocytes
State the 2 types of daughter cells differentiated into by activated B lymphocytes
- plasma cells
- memory B lymphocytes
State in what part of the body memory B lymphocytes remain in for long periods of time
Lymphoid tissue
State whether or not memory B lymphocytes can remain in lymphoid tissue for an animal’s lifetime
Yes
State what memory B lymphocytes are responsible for
Immunity following infection or vaccination
State whether or not memory B lymphocytes can divide
Yes.
State what cells memory B lymphocytes can give rise to if secondary exposure to a specific antigen occurs
Plasma cells
State what plasma cells are responsible for
Producing and secreting antibodies for immune protection
State how helper T lymphocytes can activate B lymphocytes
Cytokines
State what cells are responsible for the production of immunoglobulins
B lymphocytes
State where immunoglobulins produced by B lymphocytes are released
Blood and lymph
State what the basic unit of an antibody molecule is
Y-shaped protein
State what antibody molecules are composed of
- two long heavy chains
- two short light chains
Provide a term to describe the amino acid sequences that form of the top of the ‘arms’ of the Y-shaped antibody
Variable regions
State what allows antibodies to bind to different antigens
Variation of antibody variable regions
State what binds to identical antigen-binding sites
Identical antigens
State what the single ‘stem’ of the Y-shaped antibody is
Conserved sequence in all antibodies
Provide a term to describe the single ‘stem’ of the Y-shaped antibody
Constant region
State what both the heavy and light chains of an antibody have
- variable region
- constant region
State what naturally-produced antibodies consist of
Two identical variable regions
State what the constant region of an antigen is capable of
Binding to and initiating other immune components
State the 3 ways in which antibodies can act
- monomers
- dimers
- pentameters
State the 5 main classes of antibody molecules
- IgG
- IgM
- IgA
- IgD
- IgE
State whether or not antibodies directly destroy pathogens
No
State the 4 major functions of antibodies
- neutralisation of bacterial toxins
- neutralisation of pathogens
- agglutination
- precipitation
Describe the neutralisation of bacterial toxins of antibodies
Antibodies bind to bacterial toxins and block the action of toxins
Describe the neutralisation of pathogens of antibodies
Antibodies bind to antigens on pathogen surface required for entry into host cells to prevent pathogen invasion of host cells
Describe the agglutination of antibodies
Antibodies bind to antigens on cell surface, forming antigen-antibody complexes which activate phagocytes and the complement cascade resulting in cell destruction
Describe the precipitation of antibodies
Antibodies bind to soluble antigens, causing them to become insoluble and precipitate out of a solution
State what the antigen-antibody complex activates
- complement proteins
State 3 ways the the antigen-antibody complex inactivates antigens
- neutralisation
- agglutination
- precipitation
State what agglutination enhances
Phagocytosis
State what neutralisation enhances
Phagocytosis
State what precipitation enhances
Phagocytosis
State what the complement protein enhances
Phagocytosis and inflammation
State what cells are primarily involved in humoral immunity
B lymphocytes
State what cells are primarily involved in cell-mediated immunity
T lymphocytes
State what cell-mediated immunity is mediated by
TCR
State what TCR represnts
T cell receptors
State what T lymphocytes can be classified as depending on their function
- helper
- cytotoxic
- memory
Describe the role of helper T lymphocytes in the cell-mediated immune response
- secrete cytokines
- activate macrophages
- activate B lymphocytes
State what the secretion of cytokines by helper T lymphocytes in the cell-mediated immune response results in
Inflammation
State what occurs to the B lymphocytes activated by helper T lymphocytes in the cell-mediated immune response
Become antibody-secreting plasma cells or memory B lymphocytes
Describe the role of cytotoxic T lymphocytes in the cell-mediated immune response
- recognise
- kill
foreign, infected or abnormal host cells by releasing toxic compounds
Describe when memory T lymphocytes are produced in the cell-mediated immune response
Produced after helper and cytotoxic T lymphocytes have been activated during an infection
State what cytotoxic T lymphocytes and helper T lymphocytes differentiate into once activated
Antigen-specific memory T lymphocytes
State whether or not the memory T lymphocytes persist after the infection is resolved
Yes.
State why memory T lymphocytes persist after an infection has been resolved
To ensure prompt response should the same pathogen reinfect the organism
State what TCRs are central to
Function of T lymphocytes in the adaptive immune response
State what TCRs are composed of
Two polypeptide chains
State whether or not TCRs have a variable and constant region
Yes.
State how many antigen binding sites TCRs have
One
State whether or not TCRs bind to antigens on pathogens
No
State to what TCRs bind
Fragments of antigens that are displayed or presented on APC surfaces
State what the binding of TCRs to APCs triggers
Signal transduction in the T lymphocyte
State what signal transduction in the T lymphocyte triggered by TCR and APC binding results in
- proliferation
- cytokine release
- activation of cytotoxic function
State what T lymphocytes check
Antigens of cells they come in contact with
State what all nucleated cells have
MHCI molecules
State to what the antigens presented by surface proteins of nucleated cells are presented
MHC-I molecules of cytotoxic T lymphocytes
State what occurs when an APC engulfs a pathogen
Antigens of the pathogen are broken into smaller peptides
State what occur to antigen fragments produced by APC breakdown
Bind to MHC-II molecules inside the cell
State where the antigen-MHC-II complexes move to after binding
Cell surface
State to what cells antigen-MHC-II complexes present to after moving to the cell surface
Helper T lymphocytes
State what the TCRs on the helper T lymphocytes recognise
Antigen-MHC-II complex
State what signal transduction in the helper T lymphocyte leads to for the involved APC
Activation
State what occurs after initial exposure in the primary immune response
B and T lymphocytes form B and T memory lymphocytes
Provide the antibody that are predominately involved in the primary immune response
IgM
State what occurs much faster in the secondary immune response
Lymphocyte proliferation and antibody production
Provide the antibody that are predominately involved in the secondary immune response
IgG
Provide the antibody that are predominately involved in the secondary immune response
IgG
Describe the location of IgG antibodies
- blood
- lymph/extracellular fluid
Describe the function of IgG antibodies
- agglutination
- complement activation
Describe the location of IgM antibodies
- blood
- lymph
Describe the function of IgM antibodies
- agglutination
- complement activation
Describe the function of IgA antibodies
- mucosal immunity
Describe the location of IgA antibodies
- secretions (e.g. tears, saliva, milk)
Describe the location of IgD antibodies
- blood
- lymph
(largely present on B lymphocyte surfaces)
Describe the function of IgD antibodies
- possibly regulating innate immune response
function largely unknown
Describe the location of IgE antibodies
- blood
- lymph
(attached to mast cells)
Describe the function of IgE antibodies
- allergic reactions
Describe the structure of IgG antibodies
Monomers
Describe the structure of IgM antibodies
Pentamers
Describe the structure of IgA antibodies
Dimers
Describe the structure of IgD antibodies
Monomers
Describe the structure of IgE antibodies
Monomers
State where B lymphocytes commence differentiation
Peripheral lymphoid organs and tissues
State the major site of final B lymphocyte maturation
Spleen
Describe plasma cells
Activated B lymphocytes that produce large quantities of the same type of antibody
State what receptor helper T cells express
CD4
State what receptor cytotoxic T cells express
CD8
State what receptor T regulatory cells express
CD4 & CD25
State the role of T regulatory cells
Distinguish between self and non-self
State what cells MHCI receptor are found upon
All normal self cells
State at alternative name for TLR receptor
T cell receptor (TCR)
State to what TCR/TLRs bind to on APC
MHCII
State whether or not non-phagocytic leukocytes have MHCII markers
No.
State why non-phagocytic leukocytes do not have MHCII markers
These cells do not present fragments of antigens
State what receptors are expressed by T cells
TCR and either CD4 or CD8 (but not both)
State the role of TCR
Recognise MHCI or MHCII
Describe MHC
Gene region that codes for MHC proteins
State to what cells MHCI communicate
Cytotoxic T lymphocytes
State what MHCI proteins present
- self-antigens
- proteins produced intracellularly (such as antigens produced by virus-infected cells)
State what occurs if a cytotoxic T lymphocyte reacts to an antigen being presented by MHCI markers
Becomes activated and releases toxic peptides that damage and target the cell membrane - inducing apoptosis
State upon what cells MHCII are present
APC
State what MHCII presents
Antigens that originated extracellularly and have been processed by phagocytosis
State to what cells MHCII primarily communicate
Helper T lymphocytes
State what occurs if a helper T lymphocyte reacts to an antigen being presented by MHCII markers
Cytokine secretion attracting immune cells to infection site
State what the shape of antibodies released by plasma cells mirrors
B Cell Receptor
State what the presence of foreign antigens initiates the production of
Antibodies by plasma cells
State what an activated cytotoxic T cells will do if it encounters a body cell presenting the antigen that it is specific for
Signals to the cell to undergo apoptosis
Describe humoral immunity
Immune response involving B lymphocytes that produce specific antibodies against foreign antigens
Provide the names of the defensive molecules involved in both the innate and adaptive immune responses
- complement proteins
- cytokines
State the two classification of cytokines as defensive molecules in both the innate and adaptive immune responses
- interferons
- chemokines
Describe B lymphocytes
Lymphocytes that produce large quantities of antibodies when stimulated
Describe T lymphocytes
Lymphocyte that is responsible for the cell-mediated immune response