Section 5 Review Flashcards
Bacteria normally found at various non-sterile body sites are called
commensal organisms
The consortium of colonizing microbes has been dubbed the human ________ or ________
microbiota or microbiome
What are the benefits of Commensals
- Make vitamins and digest food
- Prevent colonization by pathogens (compete with them for food and produced antibacterial agents that kill them)
What are the risks of commensals
- might cause disease in immunocompromised patients
- anaerobic gas gangrene if it gets in surrounding tissues
What is the specificity of innate or non-adaptive immunity
non-specific
When does innate or non-adaptive immunity occur
present at birth
Does innate immunity have memory
no
What cells are involved with innate immunity
antigen-present cells such as macrophages
What is the specificity for adaptive immunity
specifc
When does adaptive immunity occur
upon exposure to antigens
Does adaptive immunity have memory
yes, faster response upon second exposure
What type of cells are involved with adaptive immunity
T-cells and B-cells
What are the types of adaptive immunity
- Humoral immunity (mediated by B-cells and activated by T-cells
- Cell-mediated immunity (T-cells)
What are the Physical barriers in innate immunity
- skin - hard to colonize
- mucous membranes - mucous secreted traps pathogens
- lungs
What are the chemical barriers in innate immunity
- acidic pH of the stomach
- Lysozymes in tears
- Lysozyme in secreted mucous destroys pathogens
- defensins
What are macrophages considered to be
antigen-presenting cells
What are the signs of inflammation
- swelling
- redness
- heat/fever
- pain
What are the steps of inflammation in innate immunity
- macrophages phagocytose bacteria
- macrophages release chemicals to start inflammation
- more macrophages are called to the site of infection
How many serum proteins (complement factors) make up the complement cascade
20
What do complement factors do
attack bacterial invaders
What do complement factors do?
Attack bacterial invaders
Effective ness by which an antigen elicits an immune response
Immunogeniciy
What are the most effective antigens or the most immunogenic
proteins
Any molecule that when introduced in the body will elicit an immune response in the form of antibody production
antigen or immunogen
Every antibody has a ________ ________ and a __________ ________
constant region, variable region
What do variable regions bind to
antigens
Every antibody has a tail known as the ___________, and two arms known as the _____________
Fc region, Fab regions
What are the 5 classes of antibodies
- IgG
- IgM
- IgA
- IgD
- IgE
Why are there 5 classes of antibodies
because of the differences in the constant regions
What does IgG contain
abundant in blood and tissue fluids
What does IgA contain
abundant in secretions such as tears and breast milk
What does IgM contain
first antibody detected during an immune response
When do antibodies appear in the blood in the primary antibody response
after several days
When do antibodies appear in the blood in the secondary antibody response
within hours due to memory from the first encounter
Which antibodies appear first in the primary antibody response
IgM and IgG
Which antibodies appear first in the secondary antibody response
IgG with a much higher response
What is the encounter in a primary antibody response
first disease encounter or first vaccination
What is the encounter in a secondary antibody response
second disease encounter or booster dose
What is the function of B-cells in adaptive immunity
- Differentiate into plasma cells that produce antibodies specific to the antigen
- memory cells that retain the memory of the antigen for faster response on the second encounter
What type of adaptive immunity is involved in the B-cells
humoral
In B-cells, what is antigen bound
circulating blood
Are there sub-types of B-cells?
no
What is the function of T-cells in adaptive immunity
- Links the humoral and cell-mediated immunity
- activates differentiation of B-cells to plasma and memory cells.
What type of adaptive immunity is involved with T-cells
Humoral and cell-mediated; both
In T-cells what is antigen bound
Present on MHC proteins on surface of APC or nucleated cell
Are their sub-types of T cells?
T helper cells
T cytotoxic cells
What lymphocytes are involved in humoral immunity
B-cells to make antibodies specific for the antigen
T helper cells assist
What antigens are recognized in humoral immunity
extracellular antigens that have been recognized by macrophages, phagocytosed, degraded, and antigens presented on the surface of APC only
What are the two mechanism levels in Humoral immunity
- Clonal selection and expansion at the B-cells level
- B-cell differentiation into plasma cells (antibody-producing cells) and memory cells for faster response on the second encounter. This step is influenced by T helper cells.
What is the host cell in humoral immunity
APC
What MHC is involved in humoral immunity
the antigen is presented on MHCII
What lymphocytes are involved in cell-mediated immunity
Cytotoxic T cells destroy the infected body cell
What levels of the mechanism are involved in cell-mediated immunity
Cytotoxic T cells recognize the antigen on surface of infected host cells
What is the antigen recognized in cell-mediated immunity
antigens are from intracellular pathogens like viruses and intracellular bacteria that did not enter the cell by phagocytosis
What is the host cell in cell-mediated immunity
any nucleated cell
What is the MHC involved in cell-mediated immunity
antigen presented on MHCI
What do Cytotoxic T cells secrete
- Perforin
- Toxic “Granzymes”
What do perforins do
forms pore in target cell membrane
What do toxic “granzymes” do
enter targe cell through pores and destroy it
What are the types of pathogens
Primary - disease in healthy host
Opportunistic - disease in immunocompromised host
What are the types of pathogenicity
- Infectivity - how easy is it for the pathogen to cause disease
- Virulence - how severe is the disease
What are the virulence factors
- pathogenicity islands
- plasmids
- phage genomes
What are the routes of transmission
- Reservoir
- Vector
An animal, bird, or insect that normally harbors the pathogen, in which the pathogen can replicate
reservoir
an insect or a tick that transmits the pathogen from one host or reservoir to the next
vector
What are the routes of transmission
- horizontally
- vertical
- accidental
transmission from one member of a species to another
horizontal transmission
the passage of a pathogen from parent to offspring
vertical transmission
when a host that is not part of the normal infection cycle unintentionally encounters that cycle. Usually, a reservoir is involved
accidental transmission
What are the portals of entry
- oral with food
- airborne
- eye
- mucosal surfaces
- parenteral (injection in the bloodstream)
What are exotoxins?
- Gram-negative and positive species
- synthesized in the cytoplasm; may or may not be secreted
- protein, generally inactivated by heat
- a distinct toxic mechanism for each
- generally very potent; some are among the most potent toxins known
What are endotoxins
- gram-negative species only
- component of the outer membrane
- Lipopolysaccharide, heat stable
- innate immune response; a systemic response leads to fever, a dramatic drop in blood pressure, and disseminated intravascular coagulation
- not very toxic; small amounts lead to an appropriate response that helps clear an infection
What happens in the Type II secretion system for bacterial exotoxins
Ex: Cholera toxin
Toxin secreted into periplasm first then moved out by a piston-like assembly
What happens in the Type III secretion system for bacterial exotoxins
Ex: Shiga toxin
Toxin moves from cytoplasm directly to the outside (molecular syringe) without passing by periplasm
What happens in the Type IV secretion system for bacterial exotoxins
Ex: Bordetella pertussis
Either could happen. toxin secreted or toxin moves
animal diseases accidentally transmitted to humans
Zoonotic disease
acquired in a hospital setting
nosocomial infections
The stimulation of an immune response by deliberate inoculation with an immunogen
immunization
