Flashcards in Immunoglobulins Deck (13):
What are immunoglobulins?
They are glycoproteins (sugar proteins)
What are immunoglobulins used for?
- Opsonize- immunoglobulins coat antigen (say bacteria) & mark it & get it phagocytized
- Neutralize- Can coat pathogen with antibodies & make it ineffective by taking up binding sites
- Activation of complement system- Antibody binds and activates complement system which introduces MAC which makes pores which destroys pathogen
What do B cells secrete? What type of response?
- Immunoglobulins (Ig's), they create immunoglobulins
- They make a lot of immunoglobulins
- But only one antigen type, one type of antibody specific to one antigen
- They have humoral response
Structure of immunoglobulin/antibody
- 2 Heavy regions & 2 light regions
- held together by disulfide bonds
- Fab region (top half) binds antigens (specific to antigen). Determines antigen binding
- Fc region (bottom half) binds to receptors on cells
Immediate response, acute infection
If we take blood sample from a patient and find IgG what does that mean?
It means they have been infected with the bug for awhile because the body takes awhile
Function of IgG
- It does everything
- Main Ig in blood
- Activate complement system, create membrane attack complex MAC.
- Kill it
What does IgM do?
- Immediate response
- Important structure (pentomeric) Fc region bound together in middle, Fab portions sticking out so it can bind many antigens (5)
- Great for agglutination because its huge
- Bind or fix complement
- Found on B cell surface
- Mucous membrane
- Gets passed from mother to baby through breast milk, baby receives passive immunity
- Gastric wall
- Intestinal mucosa
Anywhere where there is mucous
- Structure: diameric & dimer
- Does not fix complement (activate membrane attack complex)
What do the IgM & IgG have in common?
They both activate the complement system whereas the others do not
- Found in monomeric state
- Found on B-cell surface
- Does not fix complement