Lecture 8: B-Cell Effector Responses Flashcards
Antibodies are ________ proteins present in _______ but can enter ______.
Globular
Serum
Tissues
How many binding sites do Antibody have?
At least 2 binding sites
What is an Epitope?
The part of an antigen that can actually fit into the binding site of an antibody
What is a Hapten?
Low molecular weight molecules that do not themselves stimulate an immune response but can do so when bound to a carrier protein
What is a Paratope?
The part of the antibody than can actually bind the epitope
What is cross-reactivity?
Antigen is recognised by an antibody produced to a different antigen, this is due to shared structural features that match the binding sites
What is Avidity?
The total strength of the Ab-Ag binding interaction
What is Affinity?
The strength of the interaction between a single antigen-binding site and its antigen
IgE is associated with ________________
Allergic diseases i.e. Asthma and Hay fever
What is the role of IgD?
Found on B cell surfaces but it’s function is unclear
Does the brain have immunoglobulins?
Normally no Ig in the brain
Give an overview of linked recognition:
- B cells and helper T cells must recognise epitopes of the same molecular complex in order for the T cell to provide help
- Peptides presented by MHC2 on B cells to T cells
- T cell activates the B cell which dy/dx into plasma cells
What are the 3 major functions of antibodies?
Neutralisation
Opsonisation
Complement Activation
What is Neutralisation?
- Binding of ab to toxins
- Blocking bacteria’s ability to adhere
- Bind to viruses to prevent their entry into host cells
What is Opsonisation?
Coating of a pathogen to make it more easy to digest via phagocytosis
How do Ig activate the C’ system?
IgG/IgM attached to pathogens activate the classical pathway by binding C1q
How do Ig activate immune cells?
The Fc region binds to their Fc Receptors
Why are Ig needed for phagocytosis?
Binding of ab to the FcR on phagocytes allows cross linking of the FcR which activates phagocytosis
How do antibodies help NK cells?
FcR on the NK cells bind to antibodies on coated targets and initiates killing (Antibody-Dependent Cellular Cytotoxicity)
