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”
