How is active and passive immunity different?
Active Immunity is from our body's response to a pathogen, it makes memory B-cells which last up to 10 yrs. Passive Immunity has no memory. It only lasts a few months.
Example Passive Immunity
Injections of Antiboides/Immunoglobulin (artifical). Mom breastfeeding baby, IgG antibodies traveling to baby via placenta (passive).
Lymphocytes communicate with each other and with phagocytes by means of these special communicating molecules
special type of cytokines that are often used to communicate between white blood cells; effectiveness of immune system depends on the communication
Antigen presenting cells
For antigens to trigger an immune response, they must be recognized by lymphocytes, esp. T cells. When phagocytes encounter microbes, they take them in and break them down. As the microbe is being broken down into its component parts, fragments of microbial antigen are then displayed on the surface of the antigen-presenting cell where they can be recognized by TH cells.
Pentamer (can bind to 10 different pathogens). Good at Agglutination (prevents attachment). One of the first antibodies produced.
Dimer. In secretions (mucus, saliva, breast milk). Active in Agglutination & Neutalization. Binds to antigen, prevents toxin from binding to cells and being toxic.
The best antibody. IgM works until IgGs are ready. Monomer. Does all three jobs: Neutralization, Aggulatination, Opsonization.
Enhanced Phagocytosis. Phagocytes have special receptors on them which bind to the stem of antibodies. Phagocytes grab onto antibodies -- can take in microbes even if they have a capsule.
Monomer. Most often attached to basophils. Histomine. Tells basophils when to activate inflation.
Clumps pathogens, preventing their spread and reducing the number of units that phagocytes need to pick up.
Antibody-dependent cell mediated cytoxicity
Natural killer ells recognize bound antibody causing them ro release perforins and lytic enzymes
Difference from Helper T cell and Cytoxic T cells? which interacts with antigen presenting cells and b cells?
Helper T Cells play central role in coordination of immune response, releasing cytokines that activate phagocytes and other lymphocytes. Cytotoxic T cells recognize and destroy body cells that are infected or cancerous. Activation by T-dependent antigens requires cytokines from TH cells
humoral immunity steps
(1) Phagocyte eats a pathogen and displays its Ag. The phagocyte is then known as an antigen presenting cell (APC).
(2) APC attracts Helper T cell
(3) Helper T Cell activates B cell
(4) B cell becomes plasma cells AND memory cells
How are plasma and memory B cells different?
Plasma cells are short-lived; antibody-producing; antibodies produced by plasma cells are released into blood and tissue where they will bind to the antigen recognized by the B cell.
Some of the B cells differentiate into memory B cells, long-lived B cells that can rapidly divide and differentiate when they encounter antigen. Memory B and T cells are the basis for the immunologic memory that protects you from repeated infections by some pathogens
cell mediated immunity steps
The action of TC cells, "cell mediated immunity," is important in controlling viral infections and cancer, also bacterial infections.
1. Activated TC binds to MHCI of infected host cell with its T-cell receptor.
2. TC releases perforins
3. Perforins penetrate host cell membrane and cause cytoplasm to leak out.
Cell mediated immunity is mediated by ___-lymphocytes. Humoral-mediated immunity is mediated by __-lymphocytes
Cell mediated immunity always involves cells _______ cells and is directed against _______ pathogens
How is the secondary response different from the primary response?
Primary response: when the body first encounters an antigen and the immune response is triggered, the first class of antibody to be produced is IgM. After a few days, the B cells switch into production of IgG antibodies which circulate through the body, helping to clear the pathogen. During primary response, it can take more than a week before there is strong production of IgG antibody. The secondary response is quite different. When the body encounters an antigen the second time, memory B cells rapidly divide and differentiate into plasma cells and begin production of IgG and IgM antibodies. IgG production is particulary strong and far exceeds the primary response.
What is one consequence to an over-reaction of the immune system?
Autoimmune disorders like: RA, diabetes, allergies.