Exam 2 Flashcards
valence
repeated epitopes on the same pathogen
polyvalent
antigen/pathogen with many binding sites
—— epitopes trigger an immune response
immunogenic
affinity maturation occurs with Ig..
IgG
complement that binds to Fc of antibody, leading to classical pathway and MAC
C1q
70-80% of antibody in blood
IgG
5-10% of antibody in blood
IgM
first antibody made
IgM
10-20% of antibody in blood
IgA
70% of total antibody in body
sIgA
granzymes function
turn target cell’s proteins into DNA proteases
granulysin function
membrane-disrupting
works on intracellular bacteria
CD8 cells fight what kind of infections?
binding requires what?
bacterial intracellular infections
specific MHCI with specific antigen
recently-discovered antigen presenting molecule
CD1
functions like MHCI and presents glycolipids or lipoproteins
CD1
PAMP for CD1 is —–
lipid
proteosome/immunoproteasome function
processes antigens from a pathogen (usually a virus) for presentation on MHCI
antigens processed for —— presentation never touch the cytoplasm
MHCII
genus that can hide in the phagosome
Mycobacterium
CD8 binds to MHCI and produces —-, which incites an autocrine reaction
IL-2
CD4 T-cells bind to ——
MHCII
—- stimulates proliferation of CD4s before differentiation
IL-2
polarization to Th1 causes…
and requires… (4)
macrophage activation/cellular immunity
requires IL-2, IFN-y, IL-12, TGFB
polarization to Th2 causes…
and requires… (1)
humoral immunity
requires IL-4
polarization to Th17 causes…
and requires… (4)
inflammation/allergic response
requires IL-6, IL-21, IL-23, TGFB
polarization to Treg causes…
and requires… (3)
suppression of immune system
requires IL-10, IL-35, TGFB
accessory signal required for CD4s
CD30/CD36/CD28
superantigens
consequence
can bind many different receptors and trigger up to 20% of the T-cells to proliferate at one time
cause toxic shock/widespread inflammation
without T-cells, B-cells can be activated poorly by…
ex) disease condition
polysaccharide, DNA, highly valent molecules
tonsilitis
result of T-cell independent B-cell activation
low-quality IgM
no memory
connects polysaccharide to a protein, enhancing immune response
conjugate vaccine
combines S. pneumoniae capsule, not opsonized by C3b, with protein
Prevnar
pathogens that take advantage of M cells
Yersinia pseudotuberculosis
Salmonella enterica
Polio virus
gamma-delta cells function
monitor cells’ stress signals, MIC-A and MIC-B
MIC-A and MIC-B
cell stress signals, monitored by gamma-delta cells
special subset of CD8 gamma-delta cells
intestinal epithelial lymphocytes (IEL)
2 forms of leprosy
tuberculoid
lepramatous - deadly
explain tuberculoid leprosy
- Th1 cells polarized
- cellular response
- macrophages activated, fight their own infections
interleukins associated with tuberculoid leprosy
IL-2
IFN-y
explain lepramatous leprosy
- Th2 cells polarized
- humoral response
- useless IgE is made, which causes inflammatory cells to initiate tissue healing rather than infection fighting
- infection goes on unchecked
interleukins associated with lepramatous leprosy
IL-4
IL-10
3 people who used PCR to discover molecular phylogenies
Brock
Mullens
Woese
PCR uses…
16s rDNA
sequenced all the 16s rDNA of a community at one time
Pace
16s PCR process
- 1500 bp
- combined with an Amp plasmid
- plasmids introduced to E. coli & selected
- gene is sequenced
4 phyla that 90% of human commensals fall into
Actinobacteria
Proteobacteria
Firmicutes
Bacteroidetes
Proteobacteria are Gram—
Gram negative
Firmicutes are Gram—
Gram positive
Actinobacteria are Gram—
Gram positive
Bacteroidetes are Gram—
Gram negative
obligate anaerobe phylum
Bacteroidetes
3 sections of sm int are successively more…
more neutral and more colonized
—– cells per gram in small intestine
10^5
dominate the small intestine
E. faecalis and L. acidophilus
unique bacteria in the small intestine
fusiforms
—— cells per gram in large intestine
10^11 to 10^12
80% of bacteria in large intestine
Bacteroides
human feces only
Bacteroides thetaiataomicron
contributes to feces smell
butyrate
H2S
methane
reservoir hypothesis
microbes in colon recruit Ab resistance genes or toxin genes from transient bacteria and transfer them via HGT to organisms passing out
produces ammonia and changes pH in urethra
Proteus
in adult women, —— is produced in the vagina, which is used by …..
glycogen
L. acidophilus uses to make lactic acid
pH of vagina
4-5
vagina commensals in premenstrual girls/postmenopausal women
no glycogen, no Lactobacillus
higher pH
Staphylococcus, Streptococcus, Corynebacterium, E. coli
3 environments of skin
moist: nostrils, armpits, belly button
dry: arms, legs, hands, feet
sebaceous: face, scalp, upper chest and back
Moist skin commensals
Corynebacterium
Staphylococcus
Dry skin commensals
Burkholderia
Corynebacterium
Sebaceous skin commensal
Propionibacterium acnes
cause tooth decay
Strep mutans
Strep salivarius
Strep polymerize sucrose to —–, helping them stick to teeth
dextran
(glycocalyx)
cause gum disease
Porphyromonas
Prevotella
Strep intermedius
Fusobacteria
Treponema denticola
Koch’s postulates
- presence/absence rule
- pure culture
- pure culture cells cause disease
- reisolation
established that exposure to pathogen is necessary, but not sufficient
H. pylori
associated with atherosclerosis, but can be found in healthy tissue, as well as absent in some cases of atherosclerosis
Chlamydiophila pneumoniae
bacteria exhibiting differentiation
Chlamydiophila
infectious —— of Chlamydophila waits for the chance to infect a cell
endocytosis causes differentiation into ——–, which…
elementary body
reticulate body - reproduces in a vacuole, causing intracellular infection
resting/harmless state of Chlamydophila
cryptic form
fastidious organisms that Koch tried to culture
M. tuberculosis – blood and human temp
H. pylori – elevated CO2
Treponema pallidum – rabbit testicles
C. pneumoniae – human cells and elevated CO2
Bacillus —— is nonpathogenic
subtilis
B. anthracis must acquire —– to become pathogenic
2 plasmids
——- drank H. pylori, got ulcers and recovered
Barry Marshall
immunohistochemistry
antibodies against a potential pathogen are tagged with a colimetric or fluorescent dye
explain direct ELISA
antigen to well, primary antibody, enzyme - add substrate
problem with direct ELISA
too many false positives
explain indirect ELISA
antigen on well, primary antibody, secondary antibody conjugate with enzyme - add substrate
preferred ELISA
indirect
explain sandwich ELISA
capture antibody on well, antigen, primary antibody, secondary antibody conjugate with enzyme - add substrate
3 types of HIV testing
nucleic acid test (NAT)
P24 antigen test
antibody test
fifth postulate examples (4)
Does elimination of the proposed pathogen eliminate or prevent the disease?
Does antibiotic therapy eliminate the organism and cure the disease? (H. pylori)
Does vaccination against the organism prevent the disease? (HPV/cervical cancer)
Does application of hygiene, disinfection, health practices eliminate the organism and the disease?
dysbiosis
the normal commensal community undergoes a shift to an unhealthy community, stimulated by the keystone species
What is required to get gum disease with P. gingivalis?
P. gingivalis AND the commensals
mechanism of P. gingivalis gum disease
P. gingivalis promotes inflammation through C5a
Normal microbiota expand due to increase in nutrients from lysed bacteria and tissue cells
Bacterial overgrowth results in bone damage
dysbiosis requires…
a keystone species
point mutations cause genetic…
drift
phase variation
changes in the phenotype of a cell during the course of infection
phase variation increases the rate of…
inversions, deletions and duplications
3 types of phase variation
promoter inversion
transcriptional blockage
slipped-strand synthesis
2 types of HGT
tranformation
conjugation
2 types of conjugation
plasmid
transposon
flagellin switching in ——- involves…
Salmonella
inversion of a promoter for flagellin
switching between flagellin is mediated by…
DNA invertase Hin
normal flagellin
made under direction of —–
H2 (fljB)
abnormal flagellin —— is usually prevented by…
H1 (fljC)
a repressor coded for by fljA
fljB lies between….
which can become….
inverted hix repeats which can become loop structures under direction of Hin
after fljB inversion, ——- are no longer made
repressor and H2
intracellular pathogens with no cell walls
urogenital infection with HIV
Mycoplasma penetrans
M. penetrans strain —- does not express normal P24 surface lipoprotein
GTU
M. penetrans antigen
P24 surface lipoprotein
M. penetrans strain —— is wild type and expresses P24
HF-2
the termination stem loop may be very weak in the —— strain of M. penetrans
HF-2
genes with what characteristic are vulnerable to strand slippage?
what is the effect?
repeated bases or sequences
reading frame shift
virulence in B. pertussis is caused by —- gene
bvgS
bvgS contains a sequence of ——, meaning it undergoes —— mutations
GC pairs
frameshift
effect of strand slippage in B. pertussis
The virulent phenotype can easily undergo an insertion and become harmless; likewise the harmless phenotype can undergo mutation and become harmful again
Neisseria’s —- genes allow it to adhere to and invade tissue
opa
N. meningitidis has —— opa genes
N. gonorrhoeae has —– opa genes
3-4
8-13
each opa gene has ——– sequences just after the start codon
5 CTCTT
as a result of the sequence after the opa start codon, there are —– versions of Opa proteins expressed in Neisseria
13
lipooligosaccharide
in Neisseria
variant of LPS without the O-polysaccharides
Different variants of LOS result from slipped-strand synthesis activation & deactivation of enzymes ——- and ——-
glycosyltransferase
siayltransferase
wild type LOS variant
mutation variants
A is wild type
B-F are mutation types
involves enhanced rates of recombination to create new versions of genes
irreversible
antigenic variation
——- active gene(s) and ——- silent gene(s) for N. gonorrhoeae pili
1 pilE gene
20 silent pilS genes
regions at the end of pilE/S genes provides the stretch of similarity needed for homologous recombination
Sma/Cla
2 reasons we don’t have a gonorrhea vaccine
antigenic variation in pili
different Opa proteins
define transformation
a cell is lysed, releasing fragments of DNA, which are taken up by other cells and incorporated into the genome
define conjugation
one cell has the genes for conjugation (usually on a plasmid) and makes a pilus, which allows it to donate plasmids or parts of chromosomes
define transduction
donor cell is killed by a viral infection, and the viruses package up host DNA, which it then deposits in the next cell
first HGT evidence
Griffith’s experiment
“transforming principle”
Griffith said something in the dead S cells was changing R cells into S cells
who used —— to determine that DNA was being exchanged from S to R?
Avery, MacLeod and McCarty used DNase to determine that DNA was being exchanged from dead S to live R
intergenic recombination
pieces of DNA are passed between cells naturally
can take up chromosomal DNA
naturally competent
naturally competent genera (8)
Haemophilus
Neisseria
Campylobacter
Helicobacter
Streptococcus
Legionella
Bacillus
Aggregatibacter
when does competence occur?
end of log/trogophase and beginning of stationary/idiophase
sequences that serve as point of recombination throughout the chromosomes
DNA uptake sequence (DUS)
naturally competent bacteria have surface receptor that recognize…
DUSs
—– and —– are promiscuous competent bacteria
Bacillus
Streptococcus
machinery for GP DNA uptake:
pilus type
3 proteins
nucleic acid
Type IV-like pseudopilus
ComEA receives DNA
EndA degrades one strand
ssDNA enters through ComEC
invading strand replaces degraded strand
machinery for GN DNA uptake:
pilus type
3 proteins
Type IV pilE pilus
retraction through pilQ
ComEA receives DNA
ssDNA enters through ComEC
in conjugation, plasmid is cut at —- and unwound by ——
oriT
relaxase
plasmids undergo ——- replication during conjugation
rolling circle
conjugative transposition relies on the —– system
type IV secretion system
conjugation genes
tra
tra is used to make…
relaxase and pili
organism that transfers antibiotic production on plasmids
Streptomyces
have inverted and direct repeats at the ends
enhances recombination frequency
insertion sequences
IS carries —– gene for a ——-
tnp
transposase
enzyme facilitating transposition
coded for on…
transposase
IS
larger regions, with a payload region and an IS on either end
transposons
cause a huge mutation and phenotype change
transposon
rare type of transposon that can carry its own tra genes and potentially virulence genes
conjugative transposon
the scariest transposon
conjugative transposon
explain lytic infection
2 enzymes
DNase destroys host chromosome
last enzyme is lysozyme, which breaks peptidoglycan layer and releases new viruses
explain lysogenic infection
phage DNA inserted into host DNA
prophage
phage DNA inserted into host DNA
when prophage is inserted, cell is —-
immune to new infection
phage conversion
prophage causes cell to produce toxins
phase conversion of E. coli
lambda virus - becomes immune to further infection
phase conversion of C. diphtheriae
beta virus - produces diphtheria toxin
phase conversion of S. pyogenes
epsilon virus - produces scarlet fever toxin
how is specialized transduction different from generalized?
Prophage inserts at a very specific site
Virus may reliably take a virulence gene with it when it takes the host DNA by mistake
example of specialized transduction
lambda virus inserts in E. coli’s genome near gal genes for galactose utilization
Recipient of this new virus can switch from gal- to gal+
Koch’s HATERS
Theodor Billroth
Max von Pettenkofer
Rudolph Virchow
believed diseased cells only arose from diseased cells
Virchow
had 3 rules similar to Koch’s postulates, but failed to develop pure culture technique
Edwin Klebs
Koch’s first successful demonstration of postulates
tuberculosis in guinea pigs
also published a paper with similar 3 postulates to Koch’s; worked with Koch
Loeffler
cholera animal model
rabbit ligated ileal loop assay
obligate intracellular parasites that lack animal models
rickettsia
chlamydia
somnicells
when stressed, they become dormant and cannot be cultured
examples of somnicells
L. pneumophila
V. cholerae
H. pylori
authors of article did an experiment demonstrating that..
E. coli can form somnicells, and then be recovered from seawater
Acquisition of type III secretion protein by S. bongori
HGT of a PAI
Acquisition of toxin and capsule genes by Bacillus anthracis
conjugative plasmids
When bacterial DNA is inserted into the chromosome of a bacterium with the help of a virus the resulting cell is called a
transductant
When viral DNA is inserted into the chromosome of a bacterium the resulting cell is called a
lysogen
The demonstration that DNA is the transforming principle by Avery et al. using DNase to prevent transformation is analogous to which postulate?
5th
