adaptive immunity
DESCRIPTION
Adaptive Immunity. Response occurs within days of the infection Highly specific Highly diverse Memory component Major cell types involved: T cells, B cells and antigen presenting cells. Antigens and Antibodies (CH4). - PowerPoint PPT PresentationTRANSCRIPT
Adaptive ImmunityResponse occurs within days of the infection
Highly specific
Highly diverse
Memory component
Major cell types involved: T cells, B cells and antigen presenting cells
Antigens and Antibodies (CH4)Antigen – any substance that binds specifically to an antibody or a T cell receptor (TCR).
Antibody- a protein (immunoglobulin) that recognizes a specific region (component) of an antigen.
Naïve B cells – membrane-boundActivated B cells (plasma cells) – soluble (have been secreted)
Immunogen- a substance capable of eliciting an immune response.
EpitopeEpitope – portion of an antigen that reacts with an antibody or T cell receptor (TCR) also known as an antigenic determinant.
Properties of immunogenicityForeignness – molecule must be recognized as foreign.
tolerance – unresponsiveness to self antigens.
Properties of immunogenicityMolecular size –correlation between size an immunogenicity.
Bigger is better – i.e. macromolecules
Chemical composition/complexity
Properties of immunogenicityProcessing and presentation – important for T cell responses, ability of the antigen to be phagocytosed and processed.
LargeInsolubleAggregates
ImmunogenicityImmunogenicity also depends on:
Host factorsDosageRoute of entry
Recall:Jerne, Talmadge & Burnet – clonal selection theory
Antibody Structure
Antibody-Mediated Effector FunctionsOpsonization – promotion of phyagocytosis of antigens by macrophages and neutrophils.
Fc receptor (FcR)
Metzger 1994
Antibody-Mediated Effector FunctionsActivate and assist complement system
Antibody ClassesImmunoglobulin G (IgG)
Most abundant class Four subclassesActivate complement system
Antibody ClassesImmunoglobulin M (IgM)
Pentamer1st class produced in responseto an antigenActivates complement system
Antibody ClassesImmunoglobulin A (IgA)
Predominant class in secretions Secretory IgA
Antibody ClassesImmunoglobulin E (IgE)
Hypersensitivity reactions
Antibody ClassesImmunoglobulin D (IgD)
Major membrane-bound immunoglobulin expressed by mature B cells.
Antigenic determinants on immunoglobulins
IsotypeAllotypeIdiotype