Week 2 B Cells Flashcards
What are 4 components of the innate immune system?
- Physical barriers: skin, mucosal membranes
- Innate immune cells: neutrophils, monocytes, macrophages, eosinophils, basophils, NK cells and dendritic cells
- Circulating effector proteins
a, Complement system
b, Antimicrobial peptides & proteins - Cytokines
What is TNF alpha important for?
An important cytokine of innate immunity
Released by activated phagocytes
Recruits neutrophils and monocytes
Induces fever, leads to liver synthesis of actue-phase proteins
What is the important aspect of the C-reactive protein (CRP)?
An important antimicrobial peptide, it performs opsonization and activation of complement system
In medicine it is used as an inflammation marker
C3b does what?
Peforms opsonization of pathogens, even more effective than antibodies
What complement components are responsible for the membrane-attack complex?
C5b, C6, C7, C8, C9
What are the cellular components of the adaptive immune system?
Lymphocytes: T and B cells
What cells of the innate immune response connect it to the adaptive immune response?
Dendritic cells
Mononuclear phagocytes
What are the primary lymphoid organs?
Bone marrow:
- source of lymphocyte progenitors
- maturation of B cells
Thymus
- maturation of T cells
What are the secondary lymphoid organs?
Spleen - doesn’t make blood cells!
- collects antigens from the blood
- initiates adaptive immune responses
Lymph nodes
- collect antigens from tissues
- initiate adaptive immune responses
Cutaneous/mucosal ‘immune tissues’ (e.g. Peyer’s patches)
What region of the lymph nodes contains mostly B cells?
What region for mostly T cells?
B cells - primary lymphoid follicles
T cells - paracortical area
What is different about the specificity of the adaptive immune system, as opposed to the innate system?
T and B cells are specific for a large variety of antigens (epitopes)
What is different about the diversity of the adaptive immune system, as opposed to the innate system?
Clone-specific receptors (not present in the germline)
(VDJ recombination)
How do cells of the adaptive immune system reproduce in a way that creates an immunlogical memory?
“Clonal Expansion”
it takes 4-5 days before clonal expansion is complete and the lymphocytes have differentiated into effector cells, and so the first adaptive immune response to a pathogen only occurs several days after the infection begins and has been detected by the innate immune system. Most of the lymphocytes generated by the clonal expansion in any given immune response will eventually die. However, a significant number of activated antigen-specific B cells and T cells persist after antigen has been eliminated. These cells are known as memory cells and form the basis of immunological memory. They can be reactivated much more quickly than naive lymphocytes, which ensures a more rapid and effective response on a second encounter with a pathogen and thereby usually provides lasting protective immunity.
What are the components of the structure of antibodies?
- 2 identical heavy chains and 2 identical light chains, connected by S-S bonds, which makes flexible hinge region that can spread its “arms” out for better binding ability
- variable and constant regions
- variable regions contain the binding sites for epitopes
If you split an antibody into 3 parts, what are they?
The two “arms” are Fab (fragment: antigen binding)
- retain their antigen binding ability
The “tail” is Fc (fragment: crystallizable)
- Fc-receptor binding
- induces complement activation via the classical pathway
