Adaptive Immunity Flashcards
List and describe the attributes of the adaptive immune response.
Adaptive immunity: the body’s ability to recognize and defend itself against distinct invaders and their products
adaptive immunity unlike innate immunity has a resistance to a particular foreign agent (memory), its resistance increase with repeated exposure it’s traits are
Antigenic specificity: has specific responses for specific antigens
Diversity: can remember and defend against a wide range of pathogens
Immunologic memory: defense gets stronger upon repeated exposure
Self-nonself recognition: able to differentiate between normal cells/products in body and those of antigens
Define antigen and discuss the role of antigens in the immune response
antigens are a foreign substances that induces an immune
1. response in the body their role includes
2. triggering the body to respond and fight
3. being what epitopes recognize
4. can be found in pathogens, food, and dust
Properties of antigens
1. Molecules the body recognizes as foreign and worthy of attack
2. Recognized by three-dimensional regions called epitopes
3. Include various bacterial components as well as proteins of viruses, fungi, and protozoa
4. Food and dust can also contain antigenic particles
List the elements of the of the adaptive immune response, including cells, organs, tissues, signaling molecules and describe their specific roles.
Lymphatic system: screens the tissues of the body for foreign antigens
where antigen presentation occurs
Transition from innate to adaptive immune response
Composed of lymphatic vessels and lymphatic cells, tissues, organs
Lymph: similar composition to blood plasma; arises from fluid leaked from blood vessels into surrounding tissues
Flow of lymph- lymphatic vessels return lymph from tissues to circulatory system in a one-way system
Lymphoid Organs:
Primary: red bone marrow, thymus
Secondary: lymph nodes, spleen, tonsils, MALT (mucosa associated lymphatic tissue)
Lymphocytes
Identified by cluster of differentiation (CD)
Different to differentiate morphologically, have to use surface proteins
3 major populations
B lymphocytes- mature in bone marrow
Found in spleen, MALT, lymph nodes, some in blood
Primary job is to differentiate into plasma cells, the secretion of antibodies
T lymphocytes- produced in red bone marrow, mature in thymus
Circulate in lymph and in blood- migrate to secondary lymphoid organs
Mature T cells are naive until activation by antigen presentation by phagocytes
Proliferate into various effector and memory cells
CD8+ cytotoxic T lymphocyte: directly kills virally infected cells and abnormal cells
CD4+ helper T lymphocyte: helps regulate B and T cell activities
Natural Killer (NK) cells
Cytotoxic- secrete toxins onto surface of virally infected cells/tumors
Recognizes abnormal cells by multiples mechanisms
Reduced MHC I- “missing self”
Fc portion of antibodies
nonspecific
T Cell Receptor
On T cell cytoplasmic membrane
Antigen binding sites complementary to epitopes
Do not recognize epitopes directly- only through association with an MHC protein
TCR’s act primarily against cells with intracellular pathogens
B cell Receptor
Each B cell generates a single BCR- multiple copies on each cell
Recognizes only one epitope
The entire repertoire of an individual’s BCRs can recognize millions of different epitopes
Discuss antibody structure, including different types, and function.
Antibodies are immunoglobulins similar to BCR’s
Secreted by activated B cells called plasma cells
Identical antigen binding sites and specificity as BCR of activated B cell
Composed of Fc Body, 2 heavy chains and 2 light chains
Linked by disulfide bonds
Chains have constant and variable regions- form binding sites
Fc body determines type and function of antibody
Antibody Function- antigen binding sites complementary to epitopes
Activation of complement
Neutralization- bind to receptor sites on invader
Opsonization-display to phagocyte
Killing by oxidation
Agglutination- make bacterial cells clump together, bind to each other’s receptors
Antibody dependent cellular cytotoxicity
5 classes of antibodies
IgM: 1st antibody produced, neutralization/agglutination
IgG: most common, longest lasting antibody, all functions
IgA: associated with body secretions- neutralization, agglutination
IgE: response to parasitic infections, allergies
IgD: function unknown
Compare and contrast the two classes of MHC molecules.
Major Histocompatibility Complex- antigens bind in groove of MHC molecules, hold and position antigenic determinants for presentation to T cells
MHC class 1: these proteins found on all nucleated cells, show self/altered self
Display to CD8+ cytotoxic T cells
MHC class 2: these are found on antigen presenting cells (APCs) and B cells, display foreign antigen
Display to CD4+ T helper cells
