9-Immunity by B cells and Ab's Flashcards
A lot of repeats in this chapter from previous chapters objectives. I excluded the repeats.
What are the functions of Igα and Igβ on the B surface membrane?
Their tails transduce the signal of clustering of IgM’s to the inside of the B cell
What is the function of the B cell co-receptor?
it delivers the necessary signals needed to activate a naive B cell when IgM clusters form on the surface.
What is the fxn of CR2 of the B cell co-receptor?
it recognizes the complement fragments on a pathogen
What is the fxn of CD19 of the B cell co-receptor?
acts as the signaling chain of the receptor
What is the fxn of CD81 of the B cell co-receptor?
Unknown, but it does act on HepC cell surface receptor
What special type of Ag’s that B cells can react and activate to without the activation from T cells?
Thymus Independent (TI) 1 and 2
Where does the stimulus come from for TI 1 Ag’s?
They come from innate immunity products like bacterial LPS.
What types of stimuli are TI-2 Ag’s?
They are repetitive carbs or proteins present in high density on the microorganism
How does TI-1 Ag’s activate the B cell?
Basically it’s a bunch of signals from innate immunity- TLR4, BCR’s and co-receptors
How do TI-2 Ag’s activate the B cell?
They act by crosslinking BCR’s and co receptors
What are the 2 main functions of IL-4?
It not only causes growth and proliferation of T cells to TH2 cells, but stimulates B cells when they are activated from TH2 cells
Which cytokines from TH2 cells influcnce the B cell to become a plasma cell?
IL-5 and IL-6
What to centrocytes in the germinal centers compete for on the follicular dendritic cell?
Ag displayed by the FDC
Why must a centrocyte bind the Ag from the FDC and interact with the TH cell to survive?
As centrocytes compete with each other, the ones that find a match and bind are prevented from undergoing apoptosis.
Which type, either plasma or resting B cells, have surface Ig’s?
Resting B
Which type, either plasma or resting B cells, have surface MHC-II?
Resting B
Which type, either plasma or resting B cells, secrete high amts of IG’s?
Plasma
Which type, either plasma or resting B cells, are capable of growth, somatic hypermutation and isotype switching?
Resting B
Why do immunodeficient pt’s have hyper IgM syndrome?
B cells need T cells and their CD40 ligands to undergo isotype switching from IgM to other Ig’s.
What is injected to give passive immunity?
Preformed Ab’s, antiserum or T cells
How does a baby get it’s serum IgG?
It crosses the placenta from mom
How does a baby get it’s serum IgA?
Boob milk from mom
How does a baby get it’s serum IgM?
Babies make it after birth
What happens to all the Ig’s after birth?
THEY RISE
Where is FcR located?
On phahocytic cell- monocytes, macrophages, dendritic cells
What does the FcR function as?
It facilitates the uptake nad degradation of pathogens by phagocytes and professional APC’s
What does the FcR bind to on the pathogen?
IgG
How does an Ag cause degranulation of mast cells via IgE?
IgE is bound to mast cells –> Ag binds to IgE –> degranulation –> allergic response
