Chapter 17: Adaptive Specific Host Defenses Flashcards
Specificity
Refers to the adaptive immune system’s ability to target pathogens.
Memory
Refers to its ability to quickly respond to pathogens to which it has previously been exposed.
Primary Response
The immune system’s first time responding to a bacteria/virus; where programming for memory and specificity occur.
Secondary Response
Is faster and stronger as a result of the body’s memory of the first exposure; also is specific to the pathogen itself.
B Cells
Mature in the bone marrow and are responsible for the production of glycoproteins called antibodies, or immunoglobins.
Antibodies
Involved in the body’s defense against pathogens and toxins in the extracellular environment.
Humoral Immunity
Mechanisms of adaptive specific immunity that involve B cells and antibody production.
T Cells
Mature in the thymus; function as the central orchestrator of both innate and adaptive immune responses; responsible for destruction of cells infected with intracellular pathogens.
Cellular Immunity
The targeting and destruction of intracellular pathogens by T cells.
Antigens/Immunogens
Similar to PAMPs, but unique to a specific pathogen.
Antigenic
A molecule that stimulates antibody production.
Haptens
Free epitopes that are not part of the complex 3-D structure of a larger antigen.
Antibodies/Immunoglobulins
Glycoproteins that are present in both the blood and tissue fluids.
Disulfide Bonds
A covalent bond between the sulfhydryl R groups found on two cysteine amino acids.
Heavy Chains
The two largest chains on an antibody; identical to each other.
Light Chains
The two smaller chains on an antibody; identical to each other.
Fab Region
The two ‘arms’ of the Y-shaped antibody molecule; stands for ‘fragment of antigen binding’.
Variable Region
Serves as the site of antigen binding; the amino acid sequence dictates the 3-D structure, and thus the specific 3-D epitope to which the Fab region is capable of binding.
Constant Region
Includes the trunk of the Y lower portion of each arm of the Y.
Fc Region
The trunk of the Y; stands for ‘fragment of crystallization’; the site of complement factor binding and binding to phagocytic cells during antibody-mediated opsonization.
Isotype/Class
How antibodies are group; determined by the constant region.
IgG
Most abundant antibody in human blood; penetrates efficiently into tissue spaces, and is the only antibody class with the ability to cross the placental barrier, providing passive immunity to the developing fetus during pregnancy.
IgM
The first antibody produced and secreted by B cells during the primary and secondary immune responses, making pathogen-specific IgM a valuable diagnostic marker during active or recent infections.
IgA
The most common and abundant antibody class found in the mucus secretions that protect the mucous membranes; traps pathogens in mucus so that they can later be eliminated form the body.
IgD
Not secreted by B cells and only trace amounts are detected in serums; a membrane-bound monomer found in the surface of B cells, where it serves as an antigen-binding receptor.
IgE
The least abundant antibody class in serum; its role in adaptive immunity is restricted to anti-parasitic defenses.
Neutralization
Involves the binding of certain antibodies (IgG, IgM, or IgA) to epitopes on the surface of pathogens or toxins, preventing their attachment to cells.
Opsonization
The coating of a pathogen with molecules, such as complement factors, C-reactive protein, and serum amyloid A, to assist in phagocyte binding to facilitate phagocytosis.
Agglutination/Aggregation
Involves the cross-linking of pathogens by antibodies to create large aggregates.
Complement System
Promotes the inflammatory response, recruits phagocytes to site of infection, enhances phagocytosis by opsonization, and kills gram-negative bacterial pathogens with the membrane attack complex (MAC).
Classical Pathway
Requires the initial binding of IgG or IgM antibodies to the surface of a pathogen cell, allowing for recruitment and activation of the C1 complex.
Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC)
Enhances killing of pathogens that are too large to be phagocytosed.
Major Histocompatibility Complex (MHC)
A collection of genes encoding for MHC molecules found in the surface of all nucleated cells of the body.
Human Leukocyte Antigen (HLA) Genes
The MHC genes in humans.
MHC I
Found on all nucleated cells; they present normal self-antigens as well as abnormal or nonself pathogens to the effector T cells involved in cellular immunity.
MHC II
Only found on macrophages, dendritic cells, and B cells; they present abnormal or nonself pathogen antigens for the initial activation of T cells.
Antigen-Presenting Cells (APCs)
Macrophages, dendritic cells, and B cells that have the ability to present antigens specifically for the purpose of activating T cells.
T-Cell Independent Activation
What the activation of B cells without the cooperation of helper T cells is referred to and occurs when BCRs interact with T-independent antigens.
T-Cell Independent Activation
What the activation of B cells without the cooperation of helper T cells is referred to and occurs when BCRs interact with T-independent antigens.
Plasma Cells
Antibody factories that secrete large quantities of antibodies.
