module 1 Flashcards
what is the immune system
an organization of cell, tissues and organs within the body that each have their own specialized role in defending against infections
what does the immune system divided into?
- innate
- adaptive
humans and microbes
humans provide the ideal environment for many microbes
- job of the immune system to keep these microbes from entering the body
funcation of the immune system
discriminate
eliminate
discriminate
recognize self from non-self
eliminate
destroy non-self and altered self cells
dysfunctions of the immune system
- autoimmunity and hypersensitivity
- immunodeficiency
autoimmunity and hypersensitivity
misdirected or overly active immune system
immunodeficiency
underactive immune system
antigen
is a foreign protein that induces an immune response
- typically antibody generator
antibody
is a protein that is produced in response to and countering a specific antigen
what is the lymphatic system
vital system considered to be part of the circulatory system and in the immune system
- network of vessels that drains fluid (lymph) thats filtrated from the blood in the capillaries and entered the surrounding tissues called interstitial space
lymph
a colour less fluid containing white blood cells that bathes the tissue and drains through the lympthatic system into the blood stream
circulatory system
where the lymph come from and goes after being filtered
about the cells of immune system
travel between the circulatory system and the lymphatic system
- some reside in the tissues and directly interact with an antigen following a breach of the first immune barrier
lymphoid organs and tissues
Bone marrow
Lymph nodes
MALT (mucosal associated lymphoid tissues)
Spleen
Thymus
Tonsils
Peyer’s patches
Lamina propria of intestinal villi:
GALT:
BALT
Bone marrow, Structure
- Flexible tissue
-Divided in two types; yellow and red marrow - Filled with hematopoietic cells (cells lodged within the bone marrow and which are responsible for producing the cells which circulate in the blood)
bone marrow location
Central cavity inside the bones
bone marrow function , red
- Importance for the immune system
- Site of hematopoiesis (the formation and differentiation of blood cells. Origin of all immune cells)
Site of B-cell development
bone marrow function, yellow
- Some leukocyte development
- produces fat and cartilage
lymph node structure
- Small
- Bean-shaped
- Numerous
- Divided into three roughly concentric regions (cortex, paracortex, and medulla)
- Filled with lymphocytes (White blood cells which arise from the lymphoid progenitor lineage during hematopoiesis, generally refers to B), macrophages and dendritic cell
lymph node location
Grouped along the lymphatic vessels
lymph node function
- Filters the lymph
- Often it is the first organized lymphoid structure that foreign molecules encounter when first entering the body
MALT (mucosal associated lymphoid tissues), structure
- combined surface area of various areas in the body including BALT, GALT, lamina propria of intestinal villi, peyers patches, tonsils, appendix
- Filled with various types of immune cells depending on the location
MALT (mucosal associated lymphoid tissues), location
Mucous membranes lining the digestive, respiratory, and urogenital systems
MALT (mucosal associated lymphoid tissues), function
Initiates immune responses to specific antigens encountered along all mucosal surfaces
BALT
bronchus-asspciated lymphoid tissue, lymphoid structure part of the MALT located in lungs and bronchus
GALT
gut-associated lymphoid tissue; lymphoid structure part of the MALT located in the gut, peyers are part of it.
Lamina propria of intestinal villi:
thin layer of connective tissue rich in immune cells located into the lumen of the small intestine
Peyer’s patches
small masses of lympathic tissue found thrughout the ileum region of the small intestine
Tonsils:
collection of lymphoid tissue facing the aerodigestive tract, mainly located in pharynx
spleen structure
Large, ovoid
Divided into two compartments; white pulp and red pulp
white pulp
macrophages, lymphocytes, t-cells, b-cells, red blood cells
red pulp
cords of billroth (fibrils and connective tissue cells with larger population of monocytes and macrophages)
and splenic sinuses that are filled with blood
spleen location
Situated in the left abdominal cavity
spleen function
Red pulp filters the blood
White pulp is the site of development of immune responses against antigens found in the blood stream
thymus structure
- Flat
- Bi-lobed; each lobe is divided into lobules which are organized each into compartments (cortex and medulla)
- Filled with thymocytes (T-cells found in the thymus), epithelial cells, dendritic cells, and macrophages
thymus location
Situated above the heart
thymus function
Site of T-cell development and maturation
primary lymphoid organs
- thymus
- bone marrow
function or primary lymphoid organs
- lympthocye maturation into cells
b-cell =: bone marrow
t-cell: thymus
secondary lymphoid organs
- spleen
- lymph nodes
- muscosal assocaited lymphoid tissue (MALT)
function of secondary lymphoid organs
- site of lymphocye activation into effector cells
through interaction with trapped antigens
immunocompetent cell
denoting a mature lymphocyte that is capable of recognizing a specific antigen and mediating an immune response
effector cells
donating a mature lymphocyte that has been activated and mediates an immune response against a specific antigen
major histocompatibility complex Class I and discrimination
- It presents a ‘sample’ of proteins found inside the cell
- Another class of these MHC molecule (MHC II) are present on special cells of the immune system such as macrophages, dendritic cells and B-cells
- Immune cells are then able to scan their area and recognize if there are abnormalities presented via the MHC protein.
- If abnormalities or
antigens (non-self) ar4e detected, an immune response can be initiate
elimination roles
- pathogen (antigen) enters the body
- immune system rexognize the antigen
- activation of effector cells
- elinination of pathogen
innate immune
Consists of physical, soluble, and cellular barriers that are scattered throughout the body to prevent the entry of any infections agent and response non-specifically
adaptive immune
Consists of cells and soluble components capable of recognizing and responding to specific pathogens
what is adaptive further divided into
antibody-mediated humoral immunity (b-cell) and cell-mediated immunity (T-cell)
innate immunity components
- first line of defence against foreign agents
- Physical, soluble and cellular barriers
innate function
- Immediate recognition and response to invading pathogens- response within minutes or hours
- Recognizes general patterns not specific for any one antigen; limits the type of immune response initiated
adaptive components
- Humoral immunity (mediated by B-cells)
- Cell-medicated immunity (mediated by T-cells
adaptive functions
Longer time required to initate a response to invading pathogens- response within days
- Capable of recognizing and respond to specific antigens- its large diversity gives much wider range of responses that can be initiated
- Results in immunological memory- allows for quick response upon a second infection with the same pathogen
the amebocyte
is the oldest types of cells that is believed to have given rise to a type of cell found in the human immune system today- the phagocyte
phagocytes
major role in the innate immunity. They have the ability to move by pseudopodia and they can engulf free pathogens by phagocytosis
Pseudopodia
cell membrane protrusions that extend from motile and phagocytosing cells
Phagocytosis
the ingestion of bacteria or other material by phagocytes and amoeboid protozoans
Amebocyte
a mobile cell (moving like an amoeba) in the body of invertebrates. Move by pseudopodia
Evolution of lymphoid tissues GALT-
almost all vertebrates have gut-associated lymphoid tissues
Evolution of lymphoid tissues Thymus/spleen-
most vertebrates have
Evolution of lymphoid tissues Bone marrow
not many vertebrates generate lymphocytes in the bone marrow. Specifically sharks and rays are evolutionarily the earliest examples of organisms with B and T-cells
Evolution of lymphoid tissues
not all vertebrates have lymph nodes indicating that they are more recent evolutionary traits
Evolution of Innate immune system
- Found in vertebrates, invertebrates and plants
- The fruit fly is the preferred model organism for biological research because of its well-developed innate immune system
Evolution of Adaptive immune system
- Found only in subphylum vertebrata, which includes all animals with a backbone
- Only more complex organisms within this subphylum have a well-developed adaptive immune system
what does every cell originate from
pluripotent hematopoietic stem cells (HSC) in the fetal liver and the bone marrow
what is the process that gives rise to all cells
hematopoiesis
Pluripotent
cells capable of giving rise to several different cell types
Hematopoiesis
: the formation and differentiation of blood cells
Hematopoiesis is divided into two lineages:
- Myeloid
- Lymphoid
Hematopoietic stem cell
- Every blood cell arises from (HSC)
- Blood cells include; erythrocytes (red blood cells), platelets and leukocytes (white blood cells)
Erythrocytes and platelets
- Platelets are a central contributor to the process of coagulation wound healing, and fibrinolysis
- Inflammatory functions that influences both innate and adaptive immune response
Mast cells
- Located in the tissues are called granulocytes (group of white blood cells characterized by secretory granules in their cytoplasm)
- Larger granules containing histamine and other pharmacologically active substances
Neutrophil
- Most abundant type of leukocyte
Possess the characteristics of both granulocytes and phagocytes
Monocyte and macrophage
Are PHAGOCYTES
Mono- IN BLOOD
Macro- IN TISSUES
basophil
Non-phagocytic granulocytes
Lymphoid progenitor
Ability to differentiate into two major types of cells of the adaptive immune system
B-cell
T-Cell
Myeloid progenitor
Ability to differentiate into four different groups of myeloid
cells
- Granulocyte
- Monocyte
- Erythrocyte (RBC)
- Thrombocyte (platelet)
Granulocyte
- Neutrophil
- Eosinophil
- Basophil
- Mast cell
Monocyte
Macrophage
Self-renewal
Ability to divide itself to replace “older” cells to keep the pool of stem cells constant
Pluripotent (multipotent)
- Ability to differentiate into several cell types
- Once it commits to a lineage it loses its ability of self-renewal and becomes a myeloid or lymphoid
Erythrocytes and platelets, Found to participate in:
- Intervention against microbial threats
- Recruitment and promotion of innate effector cell functions
- Modulating antigen presentation
- Enhancement of adaptive immune response
formed during hematopoiesis*
mast cell function
Similar to basophils and is still under investigation, but play a role in development of allergies
Granulocyte characteristics-
polymorphic nucleus (irregular form or splits into more or less separated lobes)
Granules containing lytic enzymes (peroxidase, lysozyme aiding in elimination of infection
Phagocytic characteristic-
ability to engulf and absorb (kill) bacteria
where do monocytes travel
outside of the circulatory system by moving across blood vessel walls
when do monocytes become macrophages
through tissue
- cell gets bigger
- increase # and complexity of intracellular structures
- better phagocytic abilities
- most efficient phagocytes
basophil Granulocyte characteristics
have a polymorphic nucleus and have granules containing pharmacologically active substances (heparin, histamine)
- Largerst granules
- Least common type of granulocyte
b-cell
- Plasmocyte
- Memory b-cell
t-cell
- Helper t- cell
- Cytotoxic t-cell
- Memory t-cell
myeloid progenitor function
Generates the majority of the cells in the innate immune system
eosinophil
Are phagocytic granulocytes
Play a role in the defense against multicellular parasites like helminths
Eosinophil Granulocyte characteristic
- polymorphic nucleus and have granules able to damage parasitic membranes
eosinophil
Phagocytic characteristic
their phagocytic role is minor in comparison to other phagocytes like neutrophils
what are t-cell part of
Cell-mediated immunity, a subset of the adaptive immunity
where do t-cell mature
thymus
features of t-cells
- Non phagocytic cell
- Have specific receptors at their cell surface called T-cell receptors (TCR)
characteristics of t-cells
Specificity- one T- cell expresses many TCR that recognize the same specific antigen or epitope
Diversity- recognizes a different antigen through their TCR specificity
t-cell subsets
- Helper t-cell
- Cyctoxic t-cell
Regulatory T-cells (prevent development of autoimmune disease
- Cyctoxic t-cell
what is b-cell a part of
Humoral immunity,
where do b-cell mature
Mature in bone marrow
features of b-cells
Non phagocytic cells that have specific receptors at surface called B-cell receptor (BCR)
- BCR are the membranes-bound form of antibodies
characteristics b-cells
Specificity- one B-cell expresses many BCR that recognize the same specific antigen or epitope
Diversity- every B-cell in the body recognizes a different antigen through their BCR specificity
natural killer cells
Granular lymphocytes
about NK cells
have granules which contain perforin (a protein released by cytoplasmic granules, that destroys targeted cells by creating lesions like pores in their membranes) and granzymes (proteases released by cytoplasmic granules, that induce programmed cell death in the target cells)
what does NK cells have the ability to do
Ability to recognize tumour or virus-infected cells despite lacking antigen-speicifc receptors
- They distinguish abnormal cells and destroy them
exception of NK cells
lymphoid lineage as their role is in innate immune
Effector and memory helper T-cell
- Specialized T-cells that express the CD4 costimulatroy molecule on their cell surface
- Activated when they recognize an antigen -MHC class II (cell surface proteins essential for the adaptive immunity to recognize foreign molecules) complex
Effector cells helper t-cell
helper t-cells play a role in activation of other immune cells, such as B-cells, cytotoxic t-cells, and macrophages
Memory cells helper-t cell
generate memory cells that recognize the same specific antigen. If the pathogen reinfects the body, these cells display quicker and stronger response to eliminate the threat
Effector and memory cytotoxic T-cell
- Specialized T-cells that express the CD8 co-stimulatory molecule on their cell surface, which is why they can also be called CD8 t-cells
- Activated when they recognize an antigen MHC class I (surface protein essential for the adaptive immunity to recognize foreign molecules)
effector cells cytotoxic t-cell
role in monitoring cells of the body and eliminating any cells that display foreign antigen complexed with MHC class I
memory cytotoxic t-cell
recognize the same antigen. Makes it stronger and quicker when pathogen comes back
Plasmacyte and memory B-cell
- Plasma cells
- Are the effector form of the activated naïve B-cells (mature cells are naïve until they interact with a foreign antigen for the first time)
- Produce and secrete highly specialized antibodies,
- Generate memory cells that recognize the same specific antigen.
Dendritic cell
Can arise from either they myeloid or the lymphoid progenitor cells
- Part of innate and adaptive immunity
function of dendritic cell
- Capture and engulf antigens that evaded the innate immune response and present them to the adaptive immune cells such as T-cells, allowing an adaptive immune response to be initiated
- The link or bridge between the innate and adaptive immune systems, as they communicate between branches
- Most common subtype is Langerhans dendritic cells
Langerhans dendritic cells location
(located under the surface epithelium in the mucous mem)
Small pox vaccine 1796
- Cowpox can produce cross-immunity to small pox
- Through observation of milkmaids were generally immune to small pox
- Stop by vaccination by 1979
Pasteurization and vaccination , Small pox vaccine
- Louis pasteur was french invented the process of pasteurization -
- Demonstrated that pathogens were responsible for spoiling drinks
- Introduced the concept of using heat to destroy pathogen
Louis pasteur vaccines
- First was disease chicken cholera, introduced chickens to an attenuated form of virus and chickens became immune
Vaccines for anthrax and rabies
1890s- many scientists
- Complement was first discovered in the 1890s and was described to aid or complement the killing of bacteria
- At least 30 types of glycoprotein macromolecules that make up the complement system
- Present in the body as soluble proteins in the blood or as memebrane-assoicated proteins
These circulate in an inactive form until activated by a complement activation pathway
1908-nobel prize elie metchnikoff and paul ehrlich
- Developed the phagocytic theory
- The basis of inflammation and major defence mechanism against bacterial infection was a cellular reaction, where cells are able to move, or migrate in order to reach and internalize solid particles within intracellular vesicles
- Paul father of humoral immunity
Introduced concept of transferring blood serum to treat and counteract diphtheria
1913- Nobel prize- charles riche
- Discovered anaphylaxis through studies involving dogs
- After initial low dose of a substance with no effect, a new dose several weeks produced reaction in dogs and even proved fatal for most
- In 1901 Charles invented the word anaphylaxis which then lead the understanding of the dangers of hypersentivity reactions and to pave the way to control them
1972- Nobel prize- gerald edelman and rodney porter
- Antibody structure
- Found the structure
Allows us to better understand how the immune system reacts during infection and how each part of the antibody carriers out its tasks
1987- Nobel prize- susumu tonegawa
Determined the mechanism by which the immune system generates an almost limitless variety of antibodies
2011- Nobel prize- jules hoffman and bruce beutler
The discovery of toll-like receptors (TLRs) was an important event in the field of immunology that created a better understanding of the components of the innate immunity and their complexity
first TLR was identified in:
- 1994 but the role of TLRs was still unknown
- 1996 hoffman found that toll receptors in D
- 1998 beutler discovered that lipopolysaccharides (large molecules found on the outer membrane of gram-negative bacteria; elicit strong immune response)
bacteria
- Unicellular
- Prokaryotic organisms that have no organized internal membranous structure such as nuclei, mitochondria, lysosomes
- Genomes are circular, double-stranded DNA that do not code for as many proteins as eukaryotic genomes
example of bacteria
CHOLERA
CHOLERA characterisitcs
Is an acute, diarrheal illness caused by an infection of the intestine with the bacterium vibrio cholerae
CHOLERA Symptoms
Most often the disease is mild
1 in 10 infected persons will have severe disease characterized by profuse watery diarrhea, vomiting and leg cramps
CHOLERA Transmission
Cholera is contracted by eating or drinking foods contaminated with the bacterium
CHOLERA Diagnosis and treatment
Via stool sample and rectal swap
Can be life threatening if not treated properly through rehydration therapy and antibiotic treatment
Viruses
- Can infect a variety of organisms, from fungi and bacteria to plants and animals. However, because they rely on the host cell for metabolism and reproduction, viruses are not themselves typically considered organisms
- They infect animals are surrounded by an outer lipid envelope
what is virus composed of
- Composed of a viral genome of nucleic acid (DNA OR RNA) that is surrounded by a protein coat (capsid)
virus genome can be
double -or-single stranded (dsDNA, ssDNA, dsRNA or ssRNA)
example of virus
Influenza
Influenza Characteristics
- Contagious respiratory illness which varies in severity
Main types are A, B, C
Influenza Symptoms
Fever
Cough
Sore throat
Running nose
Headache
Influenza Transmission
Type a and b responsible for seasonal flu
Spread through droplets of saliva
Influenza Diagnosis and treatment
infection can be confirmed by quick lab tests on respiratory tests
Antiviral medication
Flu shot
fungi
- Are eukaryotic, heterotrophic organisms that have rigid cellulose or chitin based walls and reproduce primarily by forming spores
- These spores most commonly cause infection on the skin or in the lungs as you are most likely to come into contact with them through touching or inhaling them
- Divided into molds and yeast
when are people prone to fungal infections
if their immune system has been weakened or taking antibodics
molds and yeasts
molds and multicellular and yeasts are single cell
exampel of fungal infection
Vaginal yeast infection
Vaginal yeast infection Characteristics
When there is an overgrowth of yeast candida in the vagina
Relatively common as nearly 75% of all women have had one
Vaginal yeast infection Symptoms
Women usually experiences genital itching
Or rash
Vaginal yeast infection Transmission
Present in and on the body in small amounts but when an imbalance in the immune system occurs it multiplies
Vaginal yeast infection Diagnosis and treatment
By visual examination and lab tests from vaginal wall
Antifungal cream,, ointment, tablets
protozoa
- Unicellular, heterotrophic eukaryotes and examples include amoeba and paramecium
- Protozoa do not cell walls, variety of rapid and flexible movements
exampel of protozoa
Malaria
Malaria Characteristics
Mosquito-borne disease by a parasite in the genus plasmodium
Malaria Symptoms
Fever
chills
Flu
Malaria Transmission
When female anopheles mosquito (the vector) infected with the parasite bites a human, an infection begins that develops into the disease of malaria
Malaria
Diagnosis and treatment
Take preventative drugs are taken
Malaria parasites can be identified in blood by microscopic analysis
Helminths
- Parasite worms are simple invertebrates, some of which are infectious parasites
- Multicellular and have differentiated tissues
- Bc they are animals their physiology is similar in some ways to our
why are helminths difficult to treat
because drugs that kill helminths are frequently very toxic to human cell
examples of helminths
Schistosomiasis
Schistosomiasis Characteristics
Disease caused by parasitic worms or helminths
Schistosomiasis Symptoms
- some show no during early infection
- Adult worms; produce eggs that travel to intestine liver or bladder, causing inflammation or scarring
- Fever
- Chills
- Lymphoid organ enlargement
- Abdominal pain
- Diarrhea
Those are bodies reaction to eggs produced by worms not by the worms themselves
Schistosomiasis Transmission
- Parasites causing this disease are found in some types of freshwater snails and when infectious form of the parasite emerges from the snail it infects the water surrounding it
- The water affects human by infecting skin
Schistosomiasis Diagnosis and treatment
- Via stool or urine sample
- Lab tests
- Blood sample
Treatment: “praziquantel” which kills the worm
prions
new class of disease causing agent
about prions
- An emerging class of infectious agent, only a protein linked to degenerative disorders of the central nervous system (CNS)
- if protein on regular things misfold they are called prions
normal and abnormal prions
normal prion proteins can be degraded while the abnormal proteins accumulate in brain tissue as they are resistant to degradation
example of prions infectious agent
Bovine spongiform encephalopathy (BSE)
Bovine spongiform encephalopathy (BSE) Characteristics
- Also known as Mad Cow disease is a fatal neurogenerative disease of cows resulting from prions
For unknown reasons, normal proteins transform into infectious agents called prions that attack the central nervous system of a cow
Bovine spongiform encephalopathy (BSE), Transmission
Originated from food fed to cows that contains sheep products infected with scrapie- a prion disease in sheep
Bovine spongiform encephalopathy (BSE), Symptoms
- Nervousness or aggressive behaviour
- Difficulty with coordination
- Trouble standing up
- Decreased milk production
- Weight loss
- Not seen right away
But happens quickly
another exmaple of a prions infectious disease
Creutzfeldt-jakob disease (CJD)
Creutzfeldt-jakob disease (CJD) Characteristics
Is the most common human prion disease
Creutzfeldt-jakob disease (CJD), Transmission
- Exposure to brain tissue or spinal fluid from an infected individual
Inheriting mutated prion (PRNP) gene
Creutzfeldt-jakob disease (CJD), Symptoms
- Loss of muscle coordination
- Impaired memory and decision making
- Visual disturbances
- Dementia
- Coma
- Death
Creutzfeldt-jakob disease (CJD), Diagnosis and treatment
- Done by ruling out other disease using electroencephalograms (EEG), cerebrospinal fluid based tests or magnetic resonance imaging
- No specific treatment just things to treat pain
