Immune System Flashcards
(18 cards)
The part of our immune system that is always active against infection but lacks the ability to target specific invaders is known as what?
Innate immunity//nonspecific immunity
*Adaptive/specific immunity = opposite (slow but causes immunological memory)
Leukocytes are produced where and through which process ?
In bone marrow; hematopoiesis
What is the location of B cell activation & blood storage ?
Spleen
What is the difference between humoral immunity & cell-mediated immunity ?
HI: driven by B-cells & antibodies
CMI: driven by T-cells
On the skin, there are antibacterial enzymes known as ?
Defensins
A # of proteins in the blood that act as a nonspecific defense against bacteria is known as ?
Complement system
*Can undergo classical (antibody based) or alternative (non-antibody) pathway
Cells that have been infected w/ viruses produce what type of proteins ?
Interferons (prevent viral replication & dispersion)
What does an activated macrophage do ?
- Phagocytizes invader through endocytosis
- Digests invader via enzymes
- Presents little pieces of invader (peptides) to other cells via MHC
- Release cytokines: chemical substances that stimulate inflammation & recruit additional immune cells to the area
All ______ cells in the body express MHC I molecules
Nucleated
Which type of cells are able to detect a downregulation in MHC & induce apoptosis in those infected cells ?
Natural killer cells
When a pathogen is marked by an antibody from a B cell, it has been …?
Opsonized
What are the different granulocytes & what are their functions in the innate immune system ?
Neutrophils: phagocytic cells
Eosinophils: inflammation mediator (releases histamine)
Basophils: allergic responses (release histamine)
*Mast cells: mimic basophils
What happens when an antigen binds to antibodies on the surface of mast cell?
Degranulation = exocytosis of granules—–> release of histamines to induce inflammatory response
Where are naive B cells stored ?
Lymph nodes (until antigen exposure)
When B cells are exposed to an antigen, what type of daughter cells do they form ?
Plasma cells: produce large amounts of antibodies
Memory B cells: stored in lymph node until re-exposure of antigen
How does positive & negative selection of T cells differ ?
+: ONLY T cells that can respond to MHC are matured
-: apoptosis of self-reactive cells
T cell maturation is facilitated by what ?
Thymosin (peptide hormone secreted by thymic cells)
What are the 3 major types of T cells & what are their functions ?
Helper: CD4+: coordinate immune responses (release lymphokines)—-> recognize MHC II antigens
Suppressor: express CD4 & Foxp3: turn off self reactive lymphocytes (self tolerance) & tone down immune response once effectively contained
Cytotoxic (killer): CD8+: directly kills cells by injecting chemicals—-> recognizes MHC I antigens
