L-36 Flashcards
(30 cards)
What are B cells?
Lymphocytes that develop in the bone marrow
Do B cells travel to the thymus?
no
What is expressed on the surface of B cells?
Unique antigen receptors (BCR or secreted antibody)
What are plasma cells?
Activated B cells that secrete antibody
What determines the shape of plasma cells?
Extensive Golgi body necessary for antibody production
Do B and T lymphocytes develop in red or yellow bone marrow?
Red
Around how many BCRs cover the surface of each B cell?
100,000
Which main antibody isotypes are expressed on the surface of B cells?
IgM, IgD
What turns the B cell into a plasma cell?
BCR binding antigen and interaction with T cell
What does BCR have that secreted antibodies don’t?
transmembrane domain
What are the three functions of antibodies?
- neutralisation
- opsonisation
- complement activation
Which antibody isotype is best at complement activation?
IgM
When is the phagocyte attraction to antibody strongest?
When antibody is bound to antigen
What is the most abundant antibody class in the blood?
IgG
What is the function of the IgG antibody?
to opsonise/ neutralise
Which two classes of antibody provide passive immunity to babies?
IgG, IgA
Which is the only antibody class that crosses the placenta?
IgG
What class of antibody is present in secretions such as tears, saliva, mucus, and breast milk?
IgA
What is the function of IgA?
- defend mucous membranes especially in the gut
- confers passive immunity to nursing infants
What is the first antibody class produced after initial exposure to antigens?
IgM
Which antibody class is a pentamer when excreted?
IgM
What is the function of IgM?
- target extracellular bacteria
- activates complement
Which antibody class is present in the blood in low concentrations?
IgE
What is the function of IgE antibodies?
- provide immunity to multicellular parasites
- responsible for allergic reactions
