FINAL immunity Flashcards
Briefly describe the innate immune system
Non specific, quick response, no memory. Consists of external defenses, inflammation, NK cells, complement system
Briefly describe adaptive immunty
Ramps up over time via cell signaling, specific, creates memory so it can identify recurring antigens and respond quickly on subsequent exposure. Antibody and cell- mediated.
Describe the first line of defense- physical and biochemical barriers
Physical barriers that cover the body and protect from damage/ infection (i.e., skin normal microbiome)
Describe the second line of defense- inflammation
Systematic process that responds to cellular or tissue damage (regardless of type of insult). Rapid initiation of interactive systems limits tissue damage, destroy contaminating infectious microorganisms, initiate the adaptive immune response, and begin healing.
Four characteristcs of inflammation
1) occurs in vascularized tissues
2) activated rapidly after damage (within seconds)
3) depends on activity of cellular and chemical components
4) non specific
Briefly describe the process of inflammation
Vasodilation, increased vascular permeability, white blood cells adehere to endothelium and migrate into vessel
What cells are involved in innate immunity?
Phagocytes, macrophages, mast cells, neutrophils, eosinophils, basophils, NK cells, dendritic cells
What cell bridges the innate and adaptive immune system?
Dendritic (presents antigens)
This cell type destroys infected host cells to stop the spread of infection
NK cells
These cells circulate through the body looking for potential threats to engulf and destroy
Phagocytes
These cells are a phagocytic cell that has left the circulatory system to hunt for pathogens; it also releases cytokines to signal and recruit other cells to an area where there are pathogens
Macrophages
What is the role of Mast cells in innate immunity?
Found in mucous membranes and connective tissue. Important for wound healing. When activated, release cytokines and granules containing chemical molecules to create and inflammatory cascade. Key player in mounting allergic response.
What cell is the first to arrive at the site of an infection?
Neutrophils
What do eosinophils do in the innate immune response?
Target parasites, involved in allergic response
Secrete highly toxic proteins and free radicals to kill bacteria and parasites
What do basophils do in innate immune response?
Granulocyte that attacks multicellular parasites
Release histamine
What is the complement system?
Typically acts are part of innate immune system
Activation produces factors that destroy pathogens directly or can activate or increase the activity of many other components of the inflammation/ adaptive immune response. Very potent against bacteria.
3 pathways of complement system
Classical- activated by antibodies
Alternative- activated by substances found on surface of infectious organisms like bacteria and yeast
Lectin- activated by plasma proteins that recognize the carbohydrate patterns on many pathogenic microorganisms
Describe the complement cascade
1) opsonization (foreign particles marked for phagocytosis- i.e. coated by opsonins)
2) chemotaxis (attraction of macrophages to a chemical signal (diffuse from a site of inflammation)
3) cell lysis (break down/ destruction of the membrane of foreign cells
4) Agglutination- antibodies cluster and bind pathogens together
Name characteristics for the adaptive immune response
Inducible- effectors of the immune response (lymphocytes and antibodies) do not pre- exist; infection induces production in response to foreign antigen
Develops more slowly (7-14 days to respond)
Very specific- lymphocytes and antibodies induced in response to infection are very specific to infecting microbe
Effectors are long lived and systemic (long term immunological protection/ memory response against specific infections)
What is meant by the term “humoral immunity”
antibodies circulating in blood defending against extracellular microbes/ toxins). Generated by plasma cells (produce antibodies) and memory B cells (long lived memory cells that become activated once a subsequent infection occurs with the same microbe)
What is meant by the term “cellular immunity”
Effector T cells circulate in blood and tissues and defend against intracellular pathogens (i.e., viruses) and cancer cells. Consists of t reg cells, t cytotoxic cells, th cells, and memory t cells
What T cell identifies and kills target cells?
T cytotoxic