Immune System Flashcards
Natural Immunity (Innate resistance)
Resistance that exist prior to exposure to a microbe.
Born with it, based on our genotype and species.
Involves nonspecific barriers such as: skin, mucous membranes, NK cells and complimentary cytokines proteins, inflammation, and phagocytosis.
Function: to kill invading microorganisms and activates acquired immunity.
Cells in natural immunity: phagocytosis cells, antigen presenting cells, natural killer cells and complement.
Phagocytic cells
Neutrophils, macrophages, and dendritic cells.
Neutrophils
Present during acute inflammation and engulf microbes and kills them using cytoplasmic myeloperoxidase —> toxic to pathogens.
Macrophages
Derived from monocytes and leave the blood stream and differentiate into the tissues.
Dendritic cells
Engulf antigens in the epithelia of the skin, GI and respiratory tract.
Antigen Presenting Cells (APC)
Dendritic cells, macrophages, and B cells.
APC ingest and process antigens —> histocompatability complex II molecule and presented to the T-cell.
Natural killer cells
Contain granules that attack and kill virus-infected or cancerous cells
Complement cytokines
Collection of proteins which form a cascade of events to form the membrane attack complex
—> lyes a pathogen’s cell membrane
Acquired Immunity
Immunity that is obtained after exposure to an antigen.
Improves with repeated exposure and its specific.
Active acquired immunity
Produced by the host after exposure to an antigen or an immunization.
Basis of vaccines
Passive acquired immunity
Immunity acquired via the transfer of antibodies or T-cells to the recipient.
Natural passive acquired immunity
- mother to baby in breast milk or via placenta
Artificial passive acquired immunity
-antibodies are given to a recipient to provide immunity
-ex: rabies, tetanus, hepatitis, and snake bites.
-good way to fight infection, immediate protection, immunity only last 2 weeks
Humoral immunity
Immunity conferred by B-Cells
Provides immunity against some viral infections, toxin induced diseases and diseases caused by pneumococci, meningococcal, and haemophilus.
Cell-mediated immunity
Immunity conferred by T-Cells.
Immunity active against cells infected with intracellular bacteria or viruses.
Defends against CA, fungal infections, parasitic infections, tumors and is responsible for organ transplant rejection
Bone marrow
Responsible for production of immune cells and maturation of B cells
Red pulp: location of RBC storage and turnover
White pulp: immune cell interactions occur
Thymus
Shrinks but provides site for T- cell differentiation, maturation and selection.
Spleen
Lymphoid organ
Contains blood filled sinuses which filter antigens and cells from the blood
Red pulp: RBC storage and turnover
White pulp: site where immune cell interaction occur, APC present to the lymphocytes of the spleen —> trigger immune response
Spleen problems? Splenectomy or sickle cell anemia
-increased risk of streptococcal bacteria infections
—> need the pneumococcal vaccine
Lymph nodes, tonsils, and peyer’s patches
Site of antigen interact with immune cells
Peyer’s patches are lymph follicles in the mucus membrane that lines the small intestine.
CD4 cells, T-helper, or T4 cells
Function to activate macrophages, B-cells, cytotoxic T-cells, and other CD4 cells.
Release lymphokines that begin the inflammatory process
Role in mediating delayed hypersensitivity reactions (TB skin test) by TH1 and TH2
CD8 Cells, cytotoxic T-cells, killer T’s, T8 cells
Function to kill virus infected cells, tumor cells and allograft cells
By releasing cytotoxic chemicals that destroy the cell membrane or induce apoptosis.
Memory T-cells
Allows host to remember antigens and respond quicker and more vigorously after initial exposure.
Cells live for many years, can reproduce themselves.
T-regulatory cells
Slow or stop immune response once the invader is defeated
IgG
Most prominent, binds with viruses, bacteria, and toxins.
Activates the complement and binds to macrophages, primary antibody in the secondary immune response.
Levels increases with each follow up infection and levels rise at the end of a primary infection
Only immunnogobulin that passes the placenta.
IgE
Binds to mast cells, eosinophils, basophils
Involved in parasitic infections and hypersensitivity reactions
IgM
Produced early in the primary immune response
High levels of IgM —> recent infection