Name the 2 primary lymphatic organs
Bone marrow
Thymus
Name the 4 secondary lymphatic organs
- Spleen
- Lymph nodes
- Tonsils/adenoids
- Mucosa-associated lymphoid tissue (MALT)
What 2 big things occur in the bone marrow
- Location of hematopoiesis (new RBC production)
- B cell maturation
What special job does the thymus have? Is it larger or smaller as a child?
- Hosts T cell maturation
- Thymus is larger as a child then shrinks with age
What special jobs does the spleen have?
- Removes old RBCs, holds storage of RBCs, recycles iron!!!
- Synthesizes antibodies!!!
- Removes antigens by the way of blood and lymph circulation
What is the result of asplenia? (3 things)
- Increased circulating WBCs and platelets
- Diminished response to some vaccines
- Increased susceptibility to encapsulated bacteria!!! (strep pneumo, H. influenza, N. meningitides)
What is the primary job of the lymph nodes?
Filter foreign molecules and cancer cells
What organs are the first line of defense against ingested or inhaled pathogens?
Tonsils/adenoids
What is the primary function of the MALT organs?
Specializes in dealing with antigens passing through the mucosal epithelium (samples Ag and delivers to lymphoid tissue)
Compare innate vs. adaptive immunity (3 things)
Innate: First line of defense
Adaptive: Second line of defense
Innate: Nonspecific
Adaptive: Highly specific
Innate: No memory defense
Adaptive: Memory defense
How do autoimmune diseases arise?
When the adaptive immune system loses the ability to distinguish from self vs. non-self (innate immune system should only activate adaptive immune system as needed)
Compare and contrast the mechanism, cell-type, MOA, and purpose of humoral immunity vs. cell mediated immunity
Both are types of adaptive immunity
Humoral mechanism: Ab-mediated
Cell-med. mechanism: Cell-mediated
Humoral cell type: B-lymphocytes
Cell-med. cell type: T-lymphocytes
Humoral MOA: ANTIBODIES in circulating system
Cell med. MOA: DIRECT CELL TO CELL CONTACT or secreted soluble products
Humoral purpose: Primary defense against EXTRACELLULAR PATHOGENS (circulating viruses, bacteria)
Cell med. purpose: Primary defense against INTRACELLULAR PATHOGENS (viruses, fungi, intracellular bacteria, tumor antigens)
Describe the steps of activating a mature naive B-lymphocyte
- RECOGNITION: Ag binds to mature naive B-lymph. surface receptor (activation step!)
- PROLIFERATION: B-lymph. proliferate and make clones
- DIFFERENTIATION: Clones will either become a plasma cell or a memory B-cell
What do memory B-cells activate?
Years later, they can activate the SECONDARY immune response
What type of cell produces antibodies? What do Ab do?
- Ab are made from plasma cells (which came from B-lymphocytes)
- Ab tag antigens to mark them for destruction
What is the first antibody produced by plasma cells?
IgM - the first responder!
Which of the antibodies is the largest?
IgM
What is IgM’s job? What might elevated IgM levels indicate?
- IgM is very good at activating the complement system
- Indicates acute/recent infection
What is the most abundant antibody?
IgG (75% of antibodies in blood)
What is IgG’s job?
Opsonization! (Can also activate complement system)
When looking at titer labs, what would a reactive IgG, non-reactive IgM, and high avidity IgG indicate?
Past infection
- Non-reactive IgM means no current infection
- High avidity IgG means body has seen infection/virus before
When looking at titer labs, what would a reactive IgG, reactive IgM, and low avidity IgG indicate?
Primary infection
- Reactive IgM means we have current infection
- Low avidity IgG means this is the first time we are seeing infection
Where do we typically find IgA?
MALT
- Primarily in mucosal membranes and secretions
- Present in GI tract, respiratory tract, saliva, sweat, tears
What is IgA’s job?
Eliminating pathogens through mucosa
WEAK OPSONIZER and NOT good at activating complement system
