antibodies Flashcards
what are immunoglobulins
globular glycoproteins with unique structure/class synthesised by B lymphocytes or plasma cells
what is an antibody
an Immunglobulin molecule with specificity from an epitope of the molecule that make an antigens
how do antibodies bind to antigens
noncovalenty to immobilise and tag them
describe antigen binding sites
antibodies have a specific 3D shape complementary to their target
what is antibody affinity
a measure of the strength of the interaction between an antibody paratope and its epitope
describe antibody solubility
often in soluble forms as they are components of humeral (soluble) immune responses
describe the basic structure of immunoglobulins
- Y shape
- fragment antigen binding (Fab) region - arm of the Y and gives antibody is specificity
- fragment crystallisable (Fc) region - stem of Y and does not bind antigens but interacts with immune cells and proteins
what are the 4 polypeptide chains of immunoglobulins
2 identical light chains
2 identical heavy chains
what joins chains in immunoglobulins
disulphide bonds —> monomeric unit
how are heavy and light chains aligned
amino protein (NH terminal) of heavy and light chain form epitope binding site
where is the light chains encoded
chromosome 2 and 22
where are heavy chains encoded
chromosome 14
what are the domains of light chains
kappa and lambda
what are the heavy chain domains
mu, delta, gamma, epsilon and alpha
what are the antibody classes
IgM, IgD, IgG, IgA, IgE
what are the subtypes of the antibody classes
- 9 isotopes
- 4 - IgG
- 2 - IgA
- 1- IgM, IgE and IgD
what is the function of isotypes
- bifunctional
- recognise and bind to antigens forming immune complex
- promote activation of the effector mechanism and removal and degradation of antibody/ antigen complex
