Flashcards in The immune system Deck (57):
Innate (Nonspecific) Immunity
defenses that are always active
lack ability to target specific invaders over others
"specific immunity;" defenses that target a specific pathogen; slower to act, but can create immunological memory of an infection for faster attacks in the future
produces all leukocytes (WBCs) that participate in the immune system through the process of hematopoiesis
location of blood storage and activation of B-Cells, which turn into plasma cells to produce antibodies for adaptive (specific) immunity
subsection of specific immunity; involves antibodies that dissolve and act in the blood (rather than within cells)
-involves B cells
-Production of antibodies that are specific to the antigens. B-cells are lymphocytes that produce antibodies, they mature in the bone marrow and are activated in the spleen and lymph nodes.
another type of adaptive immune cells that mature in the thymus (right in front of the pericardium)
subsection of specific immunity involving T cells; immunie system is coordinate by T-cells who directly kill virally infected cells
place for immune cells to communicate and mount an attack; B-cells can activate here
Gut-Associated Lymphoid Tissue (GALT)
other immune tissue in close proximity to the digestive system (a site of potential invasion); tonsils/adenoids in head, Peyer's Patches in the small intestine, and appendix (contains lymphoid aggregates)
Hematopoietic Stem Cells
Produce granulocytes and agranulocytes. precursur cell for all other blood cells including RBCs and WBCs
Granulocytes vs aganulocytes
Granulocytes contain granules: neutrophils, eosinophils, and basophils
Agranulocytes: lymphocytes and monocytes
agranulocytes, responsible for antibody production, immune system modulation, and targeted killing of infected cells.
Phagocytic cells in the bloodstream, agranulocytes. They become macrophages in tissues (microglia, langerhans (skin), and osteoclasts).
Nonspecific/ innate Immune Response
Cells can carry these out without learning.
Immune cells learn to recognize and respond to certain antigens. The specific immune system is further divided into the cell-mediated and the humoral immune system
Noncellular Nonspecific Defenses
Normal gastrointestinal flora
Provides a physical barrier and secretes antimicrobial enzymes
Example of antibacterial enzymes on the skin
Antimicrobial and is present in tears and saliva
Is present on mucous membrane and traps incoming pathogens
Antimicrobial mechanism in the digestive system
Normal gastrointestinal flora
Provides competition, making it hard for pathogenic bacterial to grow in the gut
Set of proteins in the blood that can create holes in bacteria
Professional antigen- presenting cells
Include macrophages, dendrite cells in the skin, some B-cells, and certain activated epithelial cells
What are the differences between MHC-I and MHC-II?
MHC-I is found in all nucleated cells and presents proteins created within the cell (endogenous antigens); this can allow for detection of cells infected with intracellular pathogens (especially virus). MHC-II is only found in antigen-presenting cells and presents proteins that result from the digestion of extracellular pathogens that have been brought in by endocytosis (exogenous antigens).
Compare and contrast B and T cells:
-Both B and T cells develop in the bone marrow.
-B cells mature in Bone marrow, but are activated by spleen or lymph nodes. T-cells mature in thymus.
-B-cells major function is to produce antibodies
-T-cell's major function is to coordinate immune system and directly kill infected cells
-B and T-cells are specific/adaptive immunity
-B-cells are part of humoral system while T-cells are part of cell-mediated immunity
Pattern Recognition Receptors
They recognize the category of the invader for production of appropriate cytokines to recruit the right type of immune cells. TOll like receptors
Natural Killer (NK) Cells
A type of nonspecific lymphocyte that are able to detect the down-regulation of MHC and induce apoptosis in these virally infected cells. Cancer cells may also downregulate MHC production, so NK cells also offer protection from the growth of cancer as well.
Granulocytes (3 types)
Phagocytic, follow bacteria via chemotaxis, they can detect bacteria one they have been opsonized (tagged with antibody from B-cell). They create pus.
Involved in allergic reactions and invasive parasitic infections, they release histamine, an inflammatory mediator. Causing vasodilation and increased leakiness of blood vessels, allowing additional immune cells to move out of blood stream and into tissues.
Involved in allergic responses, least popular leukocyte in the bloodstream under normal conditions.
have smaller granules and exist in tissues, mucosa, and epithelium. Like basophils. They also release a lot of histamine in response to allergens, leading to inflammatory responses.
innate immunity; protect against viruses; cause flue-like symptoms; cells infected with viruses produce interferons that prevent viral replication and dispersion via:
1) cause nearby cells to decrease production of both viral and cellular proteins
2) decrease permeability of these cells, making it harder for a virus to infect them
3) upregulate MHC-I and MHC-II molecules, thus increasing antigen presentation and better detection of infected cells by the immune system
innate immunity; system of proteins in blood that act nonspecifically on BACTERIA; classical pathway requires binding of an antibody to a pathogen; alternative pathway doesn't require antibodies --> complement proteins punch holes in cell walls of bacteria, rendering them osmotically unstable
target a particular antigen; they contain two heavy chains and two light chains
located at the end of what is called the VARIABLE REGION (domain) at the tips of the antibody's Y; these region contains specific polypeptide sequences that will bind only one specific antigenic sequence
part of the reason why it takes so long to initiate the antibody response; B cell undergoes this process at its antigen-binding region, trying to find the best match for the antigen (improve specificity); only the B-cells that can bind the antigen with high affinity survive, providing a mechanism for generating specificity called CLONAL SELECTION
region of antibody molecule for which natural killer cells, macrophages, monocytes and eosinphils have receptors for, and can initiate the complement cascade.
isotopes of antibody
even though each B-cell makes only one type of antibody, we have many B-cells in our body that can ISOTOPE SWITCH as needed
process of marking for destruction by antibodies, which will cause AGGLUTINATION (clumping) into insoluble complexes that are ingested by phagocytes, or neutralize pathogens
can activate immune cells or mediate allergic reactions
Form from B-cells exposed to antigen and produce antibodies
Also form from B-cells exposed to antigen and lie in wait for a second exposure to a given antigen to be able to mount a rapid, robust response
helper T-cells (Th or CD4+)
respond to antigen on MHC-II and coordinate the rest of the immune system; secrete LYMPHOKINES to activate various arms of immune defense; Th1 cells and Th2 cells; loss of helper T-cells occurs in HIV (advanced AIDS); because MHC-II presents exogenous antigens, CD4+ cells are most effective against BACTERIAL, FUNGAL AND PARASITIC infections
secrete interferon gamma, which activates macrophages
activate B-cells, primarily in parasitic infections
Cytotoxic T-Cells (Tc, CTL, CD8+)
respond to antigen on MCH-I and kill VIRALLY infected cells and intracellular bacteria/fungi (by injecting toxic chemicals to promote apoptosis)
Supressor (regulatory) T-Cells (Treg)
tone down the immune response after an infection and promote self-tolerance; express FoxP3
What are the three main effects of circulating pathogens?
1. Circulating antibodies can mark a pathogen for destruction by phagocytic cells (oponization)
2. Cause agglutination of the pathogen in insoluble complexes that can be taken up by phagocytic cells
3. Neutralize the pathogen by preventing its ability to invade tissue
Positive selection of T cell
maturation of t-cells occur in thymus to select for those only capable of reacting to antigen presented on MHC are allowed to survive ( those that do not undergo apoptosis)
When T-cells that respond to self-antigens undergo apoptosis before leaving thymus
peptide hormone promoting t-cell development
Refers to the stimulation of the immune system to produce antibodies against pathogen
-natural or vaccination
Refers to the transfer of antibodies to prevent infection without stimulation of the plasma cells that produce these antibodies
a circulatory system that consists of one-way vessels with intermittent lymph nodes; connects to the cardiovascular system via the THORACIC DUCT; equalizes fluid distribution, transports fats and fat-soluble compounds in CHYLOMICRONS, and provides sites for mounting immune responses (in germinal centers)