6.5 Flashcards
What is the primary function of B-lymphocytes?
Secretion of Antibodies
Adaptive immunity can be broken into two:
- Primary Lymphoid organs
2. Secondary Lymphoid organs
What are the primary Lymphoid organs?
- Bone marrow (through Lymphoid cell lineage)
2. Thymus
What are the primary Lymphoid organs?
Spleen
Lymph nodes
cutaneous/Mucosal (Payers patches)
In Lymph nodes, what is the location of B cells?
Primary lymphoid follicles in the outer cortex of Lymph node
What are the special features of the adaptive Immunity?
Specificity
Diversity
Memory
Clonal expansion
B cells will divide into
Effector cells (plasma cells) Memory B cells
Other name for Antibodies
Immunoglobulin
Describe what are Antibodies?
Antigen-specific soluble proteins produced by B lymphocytes
2 options for Antibodies:
Membrane bound
Secreted
Structure of Antibodies
- 2x light chains
- 2x heavy chains
What connects the two chains?
Cys residues with S-S bonds
What makes up the Antigen binding site?
Variable domains (Vl/Vh)
After cleaving an antibody at the hinge region what will we get?
2x FAB (Fragment, Antigen Binding) 1x FC (Fragment, Crystallizable)
What is the total receptor diversity of Antibodies?
5x10^13
What makes the combinational diversity?
V(D)J recombination
50V, 25D, 6J
Describe IgG
- Monomer
- High conc in plasma
- Takes part in opsonization (helps phagocytes engulf their target)
- can neutralize bacterial toxins
- can cross placenta membrane
Describe IgD
- Monomer
- used as B cell receptor
Describe IgE
- Monomer
- activates mast cells
- allergic reaction
- defense against parasitic worms
Describe IgA
- Dimer
- involved in mucosal immunity
Describe IgM
- Pentamer
- largest
- used as naive B cell receptor
- involved in complement activation
What is the role of Antibodies?
Complement activation
Neutralize bacterial toxins
Opsonization
Recognition
