6 - Immune System Flashcards
What is an antigen?
B Lymphocyte vs T Lymphocyte
Molecule that bind to T-Cell Receptor or immunoglobulins (IgX)
small region of LARGE MOLECULE
B - Membrane bound Antibodies (Ig); bind variety of molecules
T - TCR; Small peptides on surface of cell
Innate Immune System
No Prior Exposure Required
Cells: Dendritic, Macrophages, Granulocytes, Neutrophils, Eosinophils, Basophils, NK Cells
Adaptive Immune System
Exposure: Prior Exposure Req’d
Cells: Lymphocytes, Plasma Cells, B Cells, T Cells
Antigen - Heavy vs Light Chain?
N-Terminal Region
Heavy = longer, Light = Shorter
Both ends have variable region (N-terminal region) which serve as antigen binding site–2x per molecule
Antibody Subclass: IgM
Pentamer and Largest
First Released–new infection
Antibody Subclass: IgA
Mucosal Immunity, Prevents pathogen entry
Associated with MALT
“Aaaaaaaachoo”
Antibody Subclass: IgD
Function as B-cell receptor
“Damn Boy, I can’t think of a mnemonic”
Antibody Subclass: IgG
Majority of antibodies in plasma
Late Response–chronic infection
Neonatal Passive Immunity
Antibody Subclass: IgE
Allergies/Parasites
Basophils/Mast Cells release Histamine
HistamEEn
What cells antibody can switch classes?
B-Cells can class switch
New) IgM -> IgG (Old
Where are lymphocytes born?
Where do pre-T cells migrate to mature?
Bone marrow
Thymus
How do pre-T cells mature in the thymus?
How are they selected?
Expression of T-Cell Receptors
Positive: Useful Antigen Receptor
Negative: Recognize self too strong = apoptosis
Histological Benefits of Thymus
Blood-Thymus barrier prevents exposure
No afferent lymph vessels
Epithelial Reticular Cells - “educate”, tight junctions and thick basal lamina protect barrier
> 95% of cells eliminated via apoptosis–fail education
Where does lymph enter the node?
Hilus through High Endothelial Venules (HEVs)
What occurs in lymph nodes?
Macrophages/lymphocytes can mount immune response, usually requires multiple passes to get “clean”
What occurs in the Germinal Center?
Mature B-Cells Proliferate/differentiate
Class Switching (M to G) can occur
MALT (Mucosa Associated Lymphoid Tissue)
High IgA
Mucosal openings, distinguished by associated epithelium
What CD can represent antigen stimulation?
CD10
What are the 3 functions of the spleen?
- Monitors Foreign Antigens in Blood
- Activates Lymphocytes (production of antibodies)
- Removes Aged (dead) RBCs
White vs Red Pulp in Spleen
White (dark blue/purple circles): T- Cells, Surround central arteries
Red Pulp (pink/red stain): Majority of space
Where are B and T cells most common?
B - Germinal Center
T - White Pulp
