EXAM 4 P2 Flashcards
B cell receptor proteins
how B cells express antibodies on their surface
what happens if the B cell receptor binds a foreign antigen
it is taken up and expressed on the cell surface in the context of a MHC 2 complex
first check
uptake and degradation of the pathogen
first check is that it’s a non-self antigen
second check
done by TH2 cells that release cytokines
the B cell now multiplies, with some differentiating into plasma cells
job is to breakout lots of antibodies and release them into the body.
what are cytokines
molecules that activate the B cell and say it’s correct in finding the antigen (aids with plasma formation)
released by TH2 cells
TH2 cells
recognize the B cell that is expressing a foreign antigen in the class 2 MHC.
release cytokines in response
innate response is immediate with foreign material
about how long does antibody production take
2 weeks, vaccines
memory cells
remain in the body for several years (long life)
differentiated B cell
able to remember they saw the antigen so if they make contact with it again, it will respond immediately.
they do not need a TH2 to bind the antigen
response is quick (1-2 days)
antibody structure
2 heavy chains and 2 light chains
proteins, variable and constant regions, disulfide bonds
IgG, IgM, and IgA
IgG
most abundant in the blood and able to cross the placenta
allows a babies immune system to be completely developed and contain antibodies from the mothers blood. high affinity
IgM
most common B cell receptor
can form a pentameric structure, the first in the most rapid response (lymph and blood). first plasma cells produced make this form.
low affinity antigen binding, but has many binding sites
bonds are not tight
IgA
forms a dimer structure
found in mucus membranes (lungs, mouth, digestive and urinary tract)
neutralizing antibodies
block the function of the antigen when directly bound to the antibody.
bind to the toucan protein and inhibit toucan from binding to the cell.
bind virus spike protein to inhibit virus from binding to the host cell
Tc cells
recognize virus infected cells
assists in the killing of infected cells when antibodies mark the infected for attack with the Tc
opsonization
increased phagocytosis
complement
series of proteins the body produces that circulate your blood all the time, interacting with antibody-antigen complexes
cause lysis/destruction of bacterial cells and opsonization
how vaccines work
first antigen injection has primary response from IgM
boosters activate memory cells
secondary response is IgG, more rapid
types of vaccine components
whole bacterial cells that have been killed by heating or chemical treatment
whole virus particles that have been killed
attenuated cells
have a mutation that prevents them from actually causing the disease
toxoids (inactivated toxin proteins)
proteins that actually cause symptoms of the infection without the toxic proteins activated
anthrax and tetanus vaccine
recombinant/synthetic antigens
pure proteins (HPV vax) and mRNA (COVID vax)
phagocytes role with antigen presentation
put fragments into their MHC and present it to cells of the adaptive response (T cells)
TH1 is activated and releases cytokines, causing inflammation
TH2 activates B cells to multiply and produce antibodies
host
organism that houses a microbe
colonization or infection
relates to growth of a microbe within the host
colonization relates to non-pathogens
infection relates to pathogens
disease
an injury or impaired function of the host
a microbe colonizes you but doesn’t cause problems
pathogen
a microbe that causes disease
obligate pathogens
only found on the host and must infect the host in order to grow and reproduce
opportunistic pathogens
commonly found in non-disease states
do not normally cause disease, but can impair host
pathogenicity
ability of a microbe to cause disease
qualitative
yes or no question
virulence
measure of the degree of pathogenicity of a microbe
the relative severity of symptoms
quantitative
most gut E. coli have low virulence
roles of normal (microbe) flora of the human body
competes with pathogens for space and nutrients
produces products that inhibit pathogens
synthesize vitamins for the host (gut)
stimulate development of immune tissues
what surfaces do microflora colonize
skin surfaces and mucus membrane surfaces
approx. 10^13 human cells and 10^14 bacterial cells
