Huma immunity Flashcards
What are the types of light chain in an antibody?
→κ or λ chain
How many types of heavy chains?
→5
→μ,δ,γ,α or ε chain
What is the hinge region made from?
→disulphide bonds
→between the cystine groups
What Bcells have antibodies?
→activate Bcells- membrane bound
→plasma
Which regions make the antigen binding domain?
→variable region of H and L
What do all chains have at the beginning and end and why?
→NH3 at the beginning
→COO3 at the end
→chains are a string of amino acids
Where is the hinge region and why?
→between CH1 and CH2 for flexibility
What group is added to the antibody to allow interaction of immune cells?
→CHO glycosylation on CH2
Which fragments make the Fc fragment?
→CH2 and CH3 domain
Which fragments make the Fab fragment?
→variable and 1st constant domain
What is the function of Fab fragment?
→binds to antigens
→antigen-binding site
What is the function of the Fc region?
→interacts with Fc receptors on macrophages and some proteins of the complement system
→bear a highly conserved N-glycosylation site
What is the Fv region?
→the smallest fragment that maintains the full binding capacity of the intact antibody
What are hypervariable regions?
→3 of them
→on heavy and light chains
What are the functions of antibodies?
→Virus & toxin neutralization- prevents pathogen-host binding →Opsonization+ ADCP →Complement fixing/+ MAC formation (CDC)-Phagocytosis or lysis →Opsonization \+ ADCC leads to NK-induced apoptosis
What is ADCC and ADCP?
→ADCC: an excess of engaged CD16A induces the release of cytotoxic granules which kill the target
→ADCP: an excess of engaged CD32A induces the phagocytosis of the microbe or target cell
What gene region fixes light chain?
→VD-J
Describe IgM
→3rd most common →heaviest →fixes complement →does not cross placenta →pentameric
What is the function of IgM?
→Main Ab of primary response
→ best at forming immune complexes fixing complement;
→monomer serves as BCR
What are the functions of IgD?
→BCR;
→indicates mature B cells
→only Ab not secreted
What are the functions of IgG?
→Main Ab of secondary responses
→neutralize toxins;
→opsonization
What are the functions of IgA?
→Secreted into mucous, tears, saliva, colostrum
What are the functions of IgE?
→allergy
→parasite
Which Igs can cross the placenta?
→IgG
Which Igs fixes complement?
→IgM
→IgG
Which Igs is heaviest?
→IgM
How many types of IgG?
→1-4
How many types of IgA?
→2
Which Igs is involved in primary response?
→IgM
What joins the two IgA monomers?
→J chain
What is another structure found in IgA?
→secretory component