B cells and their antibodies Flashcards
(54 cards)
what are B cells
-are cells that are produced from fluid called T cells
- and they produce antibodies
what is Ig
they are glycoproteins that binds specifically to the antigen and are important of humoral immunity
they are produced by B cells in response to pathogen
when is Ig called antibody
when they secreted by B cells
when is Ig called B cell receptor (BCR)
when they bound on membrane of B cell
What is the purpose of BCR
is to guide B cells in there development
what is the purpose of antibody
to protect our body against pathogens/ diseases
how does structure of antibody
- 2 alpha and beta chains
-it have 2 antigen binding sites - it have constant and variable region with 2 identical heavy chain and 2 identical light chain
what are the regions of antibody
- variable region : variable aa sequence. VH and VL, forms antigen binding sites
- Constant region : constant aa sequences. determine effector function
what are 3 fragment of antibody
- Fv region : fragment variable
- Fab region: fragment antigen binding
-FC region: fragment crystallizable
important to know that Fc and C region
C region is not Fc region
structure of antibody vs BCR
- BCR has Ig beta and Ig alpha chain used in signaling
- antibody don’t have them
how does structure of antibody relate to it’s function
- variable region: contain antigen binding site and recognize the target antigen.
-constant region: translate the binding of target antigen to the effector function, in few words it ensures proper effective function to antigen take place
how do we get antigen binding sites
how is the shape of antibody binding site
binding site shape depends on the antigen
when is small protein so called hapten it has deep pocket shape but when protein is large it has flat surfaces
how does antibody binds antigen
through non-covalent bonds ( H-bonds, hydrophobic, and Vdw forces)
antigen specificity
-Ab binds specific part of Ag called epitope
-two antibodies can binds one antigen but different two epitopes of antigen
- antigen have different epitopes
two types of epitopes
conformational (discontinuous) and linear (continuous)
what are five class of antibody isotypes
are IgG, IgM, IgD, IgE and IgA, all classes have same variable region but each class have specific constant region with specific effector function
what do B cells produce
-each B cells produce antibodies with one specific aa sequence structure
what kind of antibodies are produced by B cells
- antibodies that recognize appropriate antigen and
- antibodies that generate appropriate effector function
when does antibodies obtain their specific structure
during B cells development
how do B cell develop
what are 7 characteristic of B cells / must and their solutions
- must be able to produce antibodies against antigen they never encounter before
- by creating many different cell that produce antibodies and they will divide and survive
-must avoid producing antibodies that fight against our own body
* eliminating cells that produce unsuitable antibodies
* eliminate T cells that help B cells to produce antibody with unsuitable binding sites
-must know when to initiate response against antigen
*communicate with T cells
-must be able to increase affinity of antibodies to specific target antigen
* somatic hypermutation and selection
-must give antibodies appropriate characteristics to perform specific effector function
* change of immunoglobulin constant region/ class switch which is induced by enzyme A
-must produce large amount of antibodies to fight against antigen
* development of short lived and long lived plasma cells
-must provide body with immunological memory that ensure production of more and better antibodies
*produce long lived memory cells encoding appropriate antibodies
how does B cells be able to produce antibodies for antigen they never encounter before
by creating many different cell that produce antibodies and they will divide and survive
