Clonal Selection/Antibody Structure Flashcards
what is the Clonal Selection Theory in reference to?
immune specificity and memory
in the Clonal Selection Theory, what does recognition of an antigen signal a cell to do?
undergo proliferation
what do proliferating lymphocytes differentiate into?
effector cells and memory cells
clonal selection holds true for _________________
both B and T cells
what secretes antibodies (Ab)?
effector B cells (plasma cells)
what are immunoglobulins?
antibodies because they are globular, not fibrous
an antibody molecule monomer consists of ___________________
two heavy (H) chains and two light (L) chains
what bond links an H chain to an L chain?
disulfide (S-S) bonds
what produces the “hinge region” in an antibody molecule monomer?
the disulfide bond between the heavy (H) chains
what does cleaving the antibody molecule at the hinge regions result in?
Fab (two identical) and Fc (one) fragments
what makes up the Fab fragment?
one complete light chain and part of one heavy chain
how many binding sites for antigens are on one fab fragment?
one
what does bivalency refer to?
two Fab fragments per antibody molecule, so two identical binding sites for an antigen on each monomer
what region (Fc or Fab) determines the specific effector function(s) the immune system will take on an antigen-antibody complex?
Fc region
what is a region of about 100 amino acids tightly folded in an immunoglobulin chain?
a domain
the light chain has ____ domains and the heavy chain has ____ domains
two
four, sometimes five
what are the domains called at the N-terminus in both the heavy and light chains?
variable regions
VH and VL
what are the domains away from the N-terminus called?
constant regions
what are the parts of antibodies that actually make contact with the antigen?
complementarity-determining region (CDR)
what does idiotype refer to?
the unique antigen specificities of an antibody
how many classes/isotypes of immunoglobulins are there in mammals?
five
what is IgM found in the serum as?
a pentamer
what holds the pentamer together?
J chain polypeptide (joining chain)
what classes can form polymeric immunoglobulins?
IgM and IgA
what is IgA found in the serum as?
monomers and dimers
what is the IgA in mucosal secretions called?
secretory IgA
what are the two types of light chains?
kappa and lambda
each IgA dimer includes one _________________ and one additional polypeptide called ___________________
J chain polypeptide
secretory component (SC)
what is multiple myeloma?
cancer of a plasma cell
is myeloma protein a normal anitbody?
yes, just produced in very large amounts
what are the two types of domains that make up an immunoglobulin molecule?
variable regions (for heavy and light chains)
constant regions (for heavy and light chains)
each binding site has ___ complementarity-determining region(s): ___ variable heavy CDR(s) and ___ variable light CDR(s)
six
three
three
what is the difference between idiotype and isotype?
idiotype: antigenic specificities of an antibody
isotype: class of immunoglobulin molecule
