Lecture 12: Innate immunity Flashcards
What are the 3 lines of defense?
- surface defenses
- innate immunity
- adaptive immune system
What is the first line of defense?
Is the surface protection composed of anatomical and physiological barriers that keep microbes from penetrating sterile body compartments
What makes up the first line of defense?
physcial, chemical, and genetic barriers
What is the second line of defense?
Is a cellular and chemical system that comes immediately into play if infectious agents make it past the surface defenses.
What makes up the second line of defense?
Inflammatory response, interferons, phagocytes and complement
Where does the first line of defense have barriers?
at the portals of entry
What is the defense mechanism of the skin?
tightly packed epithelial cells
keratin
lysozyme, salt, and sweat
What is the defense mechanism of the mucous membranes?
mucociliary system
What is the defense mechanism of the eye
tears (lysozyme & salt)
epithelium
What is the defense mechanism of the mouth?
saliva (lysozyme)
What is the defense mechanism of the stomach?
acid
What is the defense mechanism of the genitourinary?
urine flow
What is the defense mechanism of the genetic defenses?
antigens
What is the reticuloendothelial system (RES)?
a communicating compartment of the body that provides passageway within and between organs and tissues, coexists and helps form niche for collection of phygocytic cells (mononuclear phagocyte system)
What is the RES packed with?
Macrophages that recognize nonself markers
What is the reticulum of the RES?
a support network of connective tissue fibers surrounding all organs
What is the thymus the site of?
White blood cell maturation
What parts of the body make up the RES?
thymus lymph nodes tonsils spleen lympoid tissue of the gut and respiratory tract
Where do macrophages of the RES wait to attack?
skin lungs liver Lymph nodes spleen Bone marrow
What is the lymphatic system?
A compartmentalized network of vessels, cells, and specialized accessory organs
What is the purpose of the lymphatic system?
Transports lymph through an increasingly larger tributary system of vessels and lymph nodes, leading to major vessels that drain back to the circulatory system
What are the 3 functions of the lymphatic system?
- return extra fluid to the circulatory system
- “drain-off” system for the inflammatory response
- watches, recognizes, and protects against foreign materials in the body through lymphocytes, phagocytes, and antibodies
What is lymphatic fluid and what is its purpose?
It is a plasmalike liquid that is carried by lymphatic circulation and it transports numerous white blood cells. It also transports fats, cellular debris, and infectious agents that have gained access to tissue spaces
What are lymphatic vessels comparable to?
thin-walled veins
Where are lymphatic vessels?
everywhere except the central nervous system, bone, placenta, and thymus
What are lymphatic vessels easily permeable to?
extracellular fluid from the circulatory system
Where are many lymphatic vessels found?
Found in high numbers in the hands, feet, and around the areola of the breast
What is the pattern of lymph flow?
Lymph flows from the extremities to the heart
How is the only way lymph can move?
Lymph moves only through the contraction of the skeletal muscles
What occurs at the thymus?
t-cell maturation
Where do t-cells go?
T cells subsequently migrate to and settle in the lymph nodes and spleen
What is the structure of lymph nodes and how are they stationed?
Small, encapsulated, bean-shaped organs
Stationed in clusters along lymphatic channels and large blood vessels of the thoracic and abdominal cavities
Where are the 3 main sites of lymph nodes found?
the armpit (axillary nodes)
groin (inguinal nodes)
neck (cervical nodes)
What does the spleen do?
serves as a filter for blood by removing worn out red blood cells as well as filters out pathogens
How do adults without a spleen differ from children without a spleen?
adults can live a relatively normal life, but children’s immune system becomes severely compromised
How is the spleen related to hemorrhages?
spleen can store blood that is released in the event of a hemorrhage
What is gut-associated lymphoid tissue (GALT) and what does it do?
discrete bundles of lymphocytes on or just beneath the intestinal mucosa
provides an effective first-strike potential against the constant influx of microbes in food
What 2 things are made of GALT?
appendix and lacteals
What are peyer’s patches?
a cluster of lymphocytes in the ileum of the small intestine
Where are sites similar to GALT found?
respiratory tract and tonsils
What do breasts of pregnant and lactating women become?
antibody-producing lymphoid tissues
What makes up whole blood?
blood cells
plasma
serum
What is hematopoiesis?
the production of blood cells
What are stem cells?
the start of new blood cells in the bone marrow
What are examples of granulocytes?
Neutrophils, eosinophils, basophils, mast cells
What are examples of agranulocytes/
Lymphocytes (B and T cells), monocytes, macrophages, dendritic cells
What are erythrocytes?
red blood cells
What are platelets?
crucial part in the blood clotting process
tiny plate-shaped cytoplasmic bags of blood-clotting chemicals
What are the types of leukocytes?
monocytes (form macrophages)
macrophages (phagocyte)
neutrophils (phagocytes and granulocytes)
What are eosinophils and what do they respond to?
Fungus, helminths, inflammatory reactions
What are basophils and what do they respond to?
inflammatory events, allergies
What do mast cells respond to?
allergic response
What are natural killer cells?
Kills host cells that contain intracellular pathogens
What are t cells?
Small lymphocyte, some kill infected host cells, others regulate adapted immune response
What are B cells?
Small lymphocyte, when activated, differentiates into plasma cells
What are plasma cells?
Lymphocyte, makes antibodies
What are dendritic cells?
Stimulates B cells to differentiate
Presentation of foreign antigens
What are the 4 mechanisms that play a role in 2nd line of defense?
Inflammation
Phagocytosis
Interferon
complement
What are the main functions of inflamation?
Mobilize and attract immune components to injury
Start tissue repair, localize and clear harmful substances
Destroy and block further invasion of microbes
What are the functions of phagocytosis?
Survey tissue and find microbes, particulates, injured/dead cells
Ingest and eliminate
Extract any immunogenic info from what was ingested
What 3 cells participate in phagocytosis?
Neutrophils, monocytes, eosinophils, macrophages
What is an early sign of infection?
increased neutrophils in the blood
What are histiocytes?
specialized macrophages, in certain tissues (lung, liver, skin, spleen, lymph, bone marrow, kidney, bone, brain) – take up permanent residence
What are PAMPs?
pathogen-associated molecular patterns, shared by many organisms… “red flags”
What are PRRs? and where are they found?
Patter recognition receptors and they are found on phagocytes, dendritic cells, endothelial cells, and lymphocytes
What do PRRs do?
They recognize and then bind PAMPs
Do all cells have PRRs?
Yes
What is chronic granulomatous disease (CGD)?
Inherited disorder
Defective phagocytes, can ingest but not kill
What happens if you have CGD?
serious recurring bacterial infections before the age of 2
What does a capsule around a cell do?
prevents phagocytosis
How does mycobacterium tuberculosis work?
it escapes destruction and uses the phagocyte to multiple
What 2 types of cells kill extracellularly?
eosinophils and nk cells
How do eosinophils kill extracellularly?
They attack helminths by attaching to them then secrete toxins to kill it. When there are high levels of eosinophils you can assume there is a helminth infection
How do Nk cells kill extracellularly?
They secrete toxins onto the surface of infected cells or tumors
What are cytokines?
small active molecules produced by monocytes, macrophages, lymphocytes, fibroblasts, mast cells, platelets and endothelial cells that are suppose to regulate, stimulate, suppress, and control cell development, inflammation, and immunity
What is rubor?
redness caused by increased circulation and vasodilation in the injured tissue
What is calor?
warmth caused by the heat given off by the increased flow of blood
What is tumor?
swelling caused by fluid escaping into the tissues
What is dolor?
pain caused by the stimulation of nerve endings
What is diapedesis?
The movement of wbcs from blood vessels to tissues
How do WBCs get transported?
The endothelial cells lining venules have adhesive receptors that captrue them and transport them to intracellular spaces
What is chemotaxis?
The movement of cells in response to a chemical stimulus for example cells swarm to infection and perform immune functions
What are the benefits of edema and leaky vessels?
the increase of fluid dilutes toxic substances and the clotting of fibrin from the vessels can prevent the spread of toxins and the neutrophils are involved in phagocytoses and destroying bacteria
What is pus?
the accumulation of white mass of cells, debris, and bacteria
What is pyogenic?
bacteria that stimulates the formation of pus
What are the classifications for a fever of unknown origin?
intermittent fever great than 101 f that lasts longer than 3 week
What are pyrogens?
substances that make the hypothalamus regulate temperature to a higher setting
What are exogenous and endogenous pyrogens?
exogenous are products of infection and endogenous are cells of the body
What are benefits of fever?
- inhibits certain viruses that need cold temperatures
- reduces nutrition of bacteria
- increases metabolism which increases immune reactions
What are the side effects of a fever?
tachycardia, tachypnea, and lowers seizure threshold
What are interferons?
proteins that prevent viral replication, but are not virus specifc
What are interferons produced by? and which is the most powerful?
alpha and gamma by t cells
beta by fibroblasts (most powerful)
What diseases are interferons used to treat?
luekemia, herpes, hepatitis,
What are defensisn?
Small peptides that function nonspecifically to protect against a broad range of pathogens
What do defensins do?
- Punch holes in cytoplasmic membranes
- Interfere with internal signaling and other metabolic processes
- Interfere with the protein that preserves the shape of bacterial proteins under heat stress
Does inflammation increase of decrease the production of defensins?
increase
How do you lose nk cells?
repeated viral infections
What is complementing?
the process of 26 blood proteins that work together to destroy bacteria and some viruses
How does complementing work?
there is a chemical series and the first is activated then the second then the third and so on?
what are the 3 pathways of how they are activated?
classical pathway, alternative pathway, and lectin pathway
What is the classical pathway?
initiated either by the foreign cell membrane of a parasite or a surface antibody
What is the alternative pathway?
activated when components of the complement pathway recognize and bind to pathogen membranes
quicker response than the classical pathway
What is the lectin pathway?
mannose binding proteins (lectins) must bind to mannose residues on the surface of pathogens in order for the pathway to proceed
Where is hemoglobin found?
RBCs
Where is transferrin found?
in blood and tissue fluids
Where is lactoferrin found?
milk and saliva
Where is ferritin found?
every cell
What are siderophores?
proteins produced by bacteria that are able to take iron from other proteins
Are peptides able to kill microbes?
yes trying to use them to make drugs
