Flashcards in Antigen Receptors: lymphocytes Deck (61):
What do helper T cells do?
What do CTL do?
Kill infected cells
What is class 1 HLA/MHC found on?
All nucleated cells
What is class 2 MHC/HLA found on?
Professional APCs (macro, dendritic, b cells, some thymocytes)
What does HLA stand for?
Human leukocyte antigen
What is an antigen?
Part of a molecule that is recognized by the immune system
What is an immunogen?
An antigen that that evokes a specific immune response
What is a tolerogen?
An antigen that induces immunologic tolerance
What is an endogenous antigen?
The body’s own cellular components or intracellular pathogens
What are self-antigens?
What are tissue specific antigens called?
What are viruses, intracellular bacteria, and parasites called?
____________ antigens are those that enter the body from outside
__________ are small molecules that cannot induce an immune response alone but they can when coupled with a carrier protein
Haptens are clinically important in what 2 processes?
Drug allergies and vaccine design
BCR are made of two ________ chains (Ig__ and Ig___). Does this molecule participate in signaling?
Invariate, alpha, beta, yes
Antibodies in circulation are what?
Surface immunoglobins in which the cytoplasmic and TM domain are removed and replaced with a tail piece
The EC tips of Ab are variable or non-variable?
What chain is the longest portion of the antibody?
What type of bonds keeps antibodies together?
What does digestion of Ab with papain do?
It breaks off the two branch regions above the hinge
What does pepsin do to Ab?
Cleaves below the hinge and leaves the binding domains all connected
When an antibody is digested by either papain or pepsin does it retain function?
No, need the whole thing to be able to have the immune system recognize it
How many hypervariable domains are on each v domain
3, they are flanked on all sides by framework regions (total of 4)
What allows flexibility of Ab?
There are hinges below the branch which allow 2 and 3D flexibility
What distinguishes the _____ different isotopes of Ig?
5; charge, size, AA sequence, carb content
Subclasses of Ig are defined by what?
Constant region of heavy chain
How many classes and subclasses are in humans of Ig?
Allotype is determined by _____________ differences on the _____ chains
Idiotype of Ig is determined by __________ ___________ on the ______ region
Antigenic determinants, variable
What is the first Ig produced in response to an antigen? What does it look like?
What antibody is produced by neonates?
What is the purpose of the J chain in Ig?
Binds to secretory cells of the mucosa
What is the predominant Ab of secondary immune responses?
What is the most abundant Ab?
IgG, it makes up 80% of total serum Ab
How many different types of IgG are there? Where are the differences found?>
4, differences are on the H chain
What subclass of IgG are most abundant?
IgG1 then 2 then 3 then 4
What activates the classical complement pathway?
IgA can be found as what two forms?
Monomer or dimer, but it is predominantly a monomer
What does IgA primarily function in?
Where is IgA found?
Breast milk (protects new borns), saliva, tears, mucus
What is the function of IgE?
Binds to blood basophils and tissue mast cells with high affinity (CD23a and CD23b)
Reacts in asthma, allergies, and helminth infections
What Ig has no know function? Where is it found in the body?
IgD; mature B cells have a receptor for it but it doesn’t activate B cells
What kind of bond do Ab form with their Ag?
Non-covalent and these are reversible
What is the strength that an Ab bonds to Ag called? What is the overall strength of Ab binding to Ag while factoring in number of binding domains?
What are Ag that require both Th and B cells to stimulate an Ab response called?
T-dependent Ags, they are proteins
What are polysaccharides and lipids that can stimulate Ab responses without T help called?
On TCR what are the different chains?
Beta and alpha chains
(The more distal ends of both are variable)
(The beta chain has a larger bump out near the TM domain)
What is the the order of the hypervariable loops on TCR from lateral to medial?
What type of T cells express gamma/delta chains?
What is the most variable region on TCR?
3, the innermost portion
What CD do all T cells express?
What does the CD3 complex ensure?
Cell surface expression of TCR and is involved in signal transduction
CD4 T cells are know as what? What do they bind to? What do they do?
Helper T cells, MHC/HLA 2, they activate macrophages and secrete cytokines and stimulate B cells to produce Ab
What are CD8 T cells called? What do they bind to? What do they do?
CTL (cytotoxic t lymphocytes), MHC/HLA1 , they kill intercellular pathogens
What do gamma/delta T cells do?
Recognize lipid Ags, can recognize DAMPs, don’t seem to be restricted to a MHC/HLA
What are not processed but bind directly to HLA class 2? What are some associated conditions
Super antigens; staph entero toxins (food poisoning), staph toxic shock syndrome, staph exfoliating toxins (scalded skin syndrome), step pyrogenic exotoxins, H1N1, SARS, Ebola
What are monoclonal Ab?
They are antibodies which recognize on epitope that originated from one cell
Antibodies targeting IL1 are important in the treatment of what disease?
Ab targeting VEGF-A are important in targeting what?