Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
193 Cards in this Set
- Front
- Back
what type of virus?
- components 2 |
- non-enveloped virus
- capside protein - genome (nucleic acid) |
|
|
what is a virus
- 3 characteristics |
- obligate intracellular parasite
- submicroscopic "filterable" infectious agent - possess genetic material |
|
|
are viruses living?
- yes or no - definition of life |
- no
- life: capacity to maintain an electrochemical gradient across a membrane - viruses cant do this |
|
|
do viruses have a membrane?
- how do they acquire a membrane - what is this called |
- viruses have no membrane
- they incorporate lipid bilayer material from the host cell - called a viral envelope |
|
|
molecular Koch's postulates
- gene's role in confirming cause |
-identify gene responsible for CS
- show gene is present in strains that cause disease - gene is absent in avirulent strains - disrupt gene reduces virulence - introduce cloned gene to avirulent strain confers virulence |
|
what type of virus
- components 4 (L to R) |
enveloped virus
- envelope and matrix proteins - envelope (lipid) - capsid - genome (nucleic acid) |
|
|
viral genome components
2 |
RNA
DNA |
|
|
viral genome form
2 |
single strand: ss
double strand: ds |
|
|
polarity for ss genome
3 types |
positive
negative ambisense |
|
|
positive sense genome
translation process similar to what |
- genome that can be translated to protein directly
- same polarity as mRNA |
|
|
negative sense genome
translation process |
- a complimentary copy must be made first
- need to make a positive sense before replication |
|
|
ambisense polarity
characteristic |
- contains pos and neg polarity genes
|
|
|
viral genome structure
3 shapes |
- linear
- segmented - circular |
|
|
reverse transcriptase
- unique to what viruses? - what does it do? |
- unique to retroviruses
- converts RNA to DNA |
|
|
coding regions: what do they produce
|
genes that produce proteins
|
|
|
open reading frame (ORF)
contains 3 things |
-start codon
-stop codon - intervening sequence of at least 100 AA |
|
|
non-structural proteins: important for what 2 things
|
- proteins important for viral replication and host cell regulation
|
|
|
structural proteins are what
4 types |
- components of the virion
- envelope proteins - matrix proteins - capsid proteins - additional proteins |
|
|
non- coding regions
are these translated? contain 3 things |
untranslated region (UTR)
- regulatory elements - scaffolding - terminal repeats |
|
|
virulence factor?
definition are they essential? coding or noncoding area |
- gene or untranslated region not essential for virus replication
- can be either coding or noncoding region |
|
|
how are viruses identified
|
sequencing
|
|
|
capsid
what is it? |
protein shell surrounding the nucleic acid genome
|
|
|
acronyms for capsid
|
capsomeres
nucleocapsid proteins nucleoproteins |
|
|
2 types of capsid
shapes |
symmetrical
complex |
|
|
2 types of symmetrical capsids
shape example of virus |
icosahedral: 20 sided structure, Norwalk virus
helical or cylindrical: capsomeres arranged in a spiral staircase, Rhabdovirus (rabies) |
|
|
animal viruses with helical capsids are enveloped or nonenveloped
|
enveloped
|
|
|
capsid function
4 things |
-genome unpacking
- host cell attachment (for non-enveloped) - genome released into cells - regulatory functions (non-structural proteins) |
|
|
envelope: lipid bilayer
what forms it? 4 things |
- nuclear membrane
- ER - Golgi - plasma membrane |
|
|
glycosylated and non glycosylated proteins:
- names for each where are they located |
- envelope proteins (glycosylated)
- matrix proteins (matrix proteins) |
|
|
envelope functions:
5 things |
- carries attachment proteins
- carries host cell entry proteins (fusion) - protects nucleocapsid - facilitates direct cell-cell transmission of virion (escapes Ab exposure) - camouflage |
|
|
prion: "proteinaceous infectious particles"
resistant to? 3 things |
-heat
- UV radiation - ionizing radiation |
|
|
do prions contain nucleic acid
|
no
|
|
|
define:
PrPc PrPsc |
- host encoded prion protein
- modified infectious form |
|
|
prion conformation change
is it a foreign protein? change causes increased what |
PrPc changed to PrPsc
- protein changed, its not foreign - conformation change allows for protein aggregation b/c of increased beta-sheet structure |
|
|
source of prions: 3
|
- spontaneous
- mutation - infection: introduction of PrPsc material form infected animals |
|
|
prion mech of damage
what do they form |
- misfolded proteins propagate PrPsc forms
- form beta-sheet structure - allows them to aggregate |
|
|
chaperone protein function
|
helps other proteins form properly
|
|
|
pathogenesis of prion dz
5 steps |
- ingestion of PrPsc
- PrPsc enter circulation, cross BBB - neurons uptake PrPsc and initiate change from PrPc to PrPsc - PrPsc cant be removed, accumulate, release PrPsc to infect other neurons - sponge like holes left in brain |
|
|
virus classificatoin criteria
4 things |
- presence or absence of envelope
- capsid symmetry - viral genome characteristics - NUCLEOTIDE SEQUENCING |
|
|
what determines if a host becomes infected: 2 things
|
susceptibility
risk |
|
|
what is susceptibility
|
presence of receptor and machinery in host cell to support virus replication
genetic predisposition |
|
|
what is risk
other factors involved: 4 things |
probability of host becoming infected
- environment - behavior/temporal factors - presence of preventative measures - vector requirements |
|
|
arbovirus: what is it
|
arthropod born virus
|
|
|
virus attachment
- how is it mediated - how is it blocked |
- receptor mediated
- blocked by Ab |
|
|
neutralizing Ab
|
Ab that blocks attachment
- directed at non-conserved peptide region |
|
|
virus replication steps
5 |
attachment
entry uncoating transcription genome synthesis |
|
|
DNA viral transcription process
2 steps |
-host or virus DNA dependent RNA polymerase generates viral mRNA
- mRNA translated into viral proteins |
|
|
RNA viral transcription
- what does it require |
requires viral RNA dependent polymerase to make mRNA
|
|
|
positive sense vs negative sense RNA viruses with respect to RdRp
|
negative sense RNA viruses must carry premade RdRp for use upon cell entry
|
|
|
where do DNA viruses replicate
what do they use from the host 2 exceptions |
replicate in nucleus
use host DdDp to make copies poxvirus and herpesvirus use viral polymerase |
|
|
RNA genome synthesis: use what type of polymerase
exception |
replicate through RdRp
retroviruses: use reverse transcriptase |
|
|
minamilism
|
max strength with minimal proteins used
|
|
|
early translational products
|
non structural proteins
- polymerases - regulatory proteins |
|
|
late translational products
|
structural proteins
- capsid proteins - envelope glycoproteins |
|
|
productive vs abortive infection
|
productive: production of infectious viral progeny
abortive: replication steps occur, no mature virus made |
|
|
dsDNA virus example
# proteins produced what does vhs do what does vp16 do |
- alpha herpes virus (HSV-1)
- 80 proteins - vhs cuts up host cell mRNA, first step to block host cell defenses - vp16 facilitates transcription of herpes virus RNA |
|
|
positive strand RNA virus example
# proteins produced where does replication occur |
Corona virus (FIPV)
8 proteins replication in the cytoplasm |
|
|
retrovirus replication
where does replication occur name the important intermediate step - what is important about this |
- even though it is an RNA virus, it replicates in the nucleus (DNA step)
- provirus - if virus infects germ cell, virus becomes generational |
|
|
do RdRp viruses have proof reading function
- error rate - no two viral genomes are identical: what is this called |
- no 5'3' exonuclease
- no proofreading - error 1/10,000 - quasispecies |
|
|
cells for growing virus
3 lines - info for each |
- primary cell line (kidney, fetal cells), used for 40 generations
- transformed cell line, immortal, neoplastic - continuous cell line, non transformed but are immortal (fetal origin) |
|
|
outcomes after viral infection to cells
4 |
- cytopathic death (necrotic, apoptotic, atypical)
- cytopathic non death (syncytium: fusion into multinucleated cell) - non cytopathic (no visual change to cell monolayer) - tranformation (immortalization) |
|
what is syncytia, why do viruses use this method
|
- viruses with fusion proteins in envelope promote fusion of infected cell with those around it
- cells fuse to form a single large multi nucleated cell - virus spreads w/o exiting the cell, avoid neutralizing Ab |
|
|
apoptotic pathways
2 define them |
-intrinsic: initiated in response to unscheduled change in DNA or protein synthesis
- extrinsic: engagement of Fas ligand receptor on cell surface |
|
|
disease definitoin
|
a condition that impairs normal function
|
|
|
pathology def.
|
a departure or deviation from a normal condition
|
|
|
name 7 sites for virus entry, and the 2 most important
- b/c they are this type of surface |
skin, blood, resp tract, oropharynx, GIT, urogenital, conjunctiva
- RESPIRATORY AND GIT - mucosal surfaces |
|
|
how do arboviruses enter host
|
through arthropod vector
|
|
|
how do viruses end up infecting the CNS
what is special about nervous system that allows proliferation of virus |
- enter through mucosal surface, access ECM and find peripheral nerve
- nervous system is immunoprivelaged so virus replicate with no defense |
|
|
what is the prodromal stage, why is it important
|
- period of time when virus is being shed without CS
- allows for spread of virus |
|
|
neonatal mouse example given virus <24 hours old
what happened |
- no immune system <24 hours old
- became tolerant of virus (seen as self) - mouse becomes persistently infected - if immunosuppressed mouse infected with virus is given T cells from acutely infected mouse, mouse dead - T cells actually cause death |
|
|
how long will viral infection usually last
- why is this important |
- usually last 2 weeks
- this is why it takes 2 weeks for vaccination to work |
|
|
what are PAMPS
name 3 how are they recognized by cells |
-pathogen associated molecular patterns
- dsRNA - dsDNA (in the cytoplasm) - viral proteins - recognized by toll like receptors (TLRs) on cell surface |
|
|
how does initial recognition of infection occur
- danger signals: name 2 - what do vaccinces have similiar to these |
- necrotic death
- inflammation - vaccines have adjuvants that produce danger signal |
|
|
how does RNAi work
- what is the result |
- recognizes dsRNA
- dices up the ds to eventually form ss - makes more dsRNA in the end - AMPLIFICATION of viral genome |
|
|
what cytokines have direct antiviral actions
|
interferons
|
|
|
cytokines operate at different distances: name 3
when and how can they be measured |
- autocrine: cannot be measured in body fluids
- paracrine: detected during pathological states - endocrine: measured in body fluids |
|
|
cytokines are pleiotropic: more than one action
- name the cytokine - name 3 areas of action - what does the cytokine do in each |
- innate: IFN-antiviral
- adaptive: IFN- Th1 - inflammatory: IFN induction of NO |
|
|
IFN type 1, why is it produced, what does it do
|
- virus infected cells produce Type 1 IFN
- induces a virus resistant state surrounding cells - paracrine activity |
|
|
Type 2 IFN "immune IFN"
also called IFN gamma produced by 2 types of cells |
- NK cells
- T cells |
|
|
what is PKR
it does 3 things, what are they |
- PKR is an IFN stimulated protein
- induction of apoptosis - INHIBITION OF PROTEIN SYNTHESIS - activation of other antiviral pathways |
|
|
what MHC class to NK cells bind to
what is the end result for the cell |
MHC class 1
apoptosis |
|
|
acquired or adaptive immunity
2 responses, what cells are produced |
TH1: CTLs
TH2: Ab |
|
|
what type of protection does the adaptive immune system create? 1 word
|
MEMORY
|
|
|
stages of adaptive immunity
6 stages |
- recognition of Ag (clonal selection)
- proliferation of B and T cells (clonal expansion) - implement effector functions (cytokines, killing, Ab) - maturation of effector functions (affinity maturation) - removal of unused lymphocytes (apoptosis) - memory |
|
|
2 roles of adaptive immunity
|
- virus-specific Ab prevents infection of cells (neutralizing Abs)
- cell mediated immunity (CTL clears viral infected cells) |
|
|
What type of immunity can be transferred b/w animals
2 ways this is done |
- humoral immunity can be transferred
- Passive Ab (colostrum and transplacental) - gamma globulin (Ab) therapy |
|
|
can cell mediated immunity (CMI) be transferred b/w animals
|
no
|
|
|
TH1 immunity is what kind
|
CMI
|
|
|
TH2 is what kind of immunity
|
humoral
|
|
|
what does the APC communicate with in TH1 immunity
|
- APC presents Ag to TH1 cell via MHC II
- TH1 cells communicates with CD4 |
|
|
what does the TH1 cell produce after formation of the tri molecular complex with the APC
what effect does this have |
TH1 cell produces IL2
- drive proliferation of T helper cells - autocrine loop to drive its own proliferation |
|
|
in CMI, what does the virus infected cell present to CTL, and what does the CTL add to the TMC (tri molecular complex)
what does this form |
MHC I
tri molecular complex: CTL has CD8, infected cell has MHC I |
|
|
what forms the TMC in TH2 humoral immunity
what is the result: 3 things |
- B cell has MHC II
- TH2 cell has CD4 - Ag - B cells then: proliferate, differentiate into plasma cells, make Ab |
|
|
what is the purpose of CD4 and CD8 in the TMC
|
- stabilize the binding
|
|
|
for Class I and II MHC, which results in killing and which is help
which CD is involved in each |
MHC I: CD4 kill
MHC II: CD8 help |
|
|
what 3 things are involved in CTL killing of a virus infected cell
|
- granzyme in CTL
- perforin pore in infected cell - FAS ligand binding b/w the cells |
|
|
what are the 5 different Ab produced, what are their characteristics
|
- IgG: virus neutralization
- IgE: parasitic, allergies - IgA: mucosal surfaces - IgM: pentameric Ab, first produced - IgD: naive B cells |
|
|
which Ab has high avidity, why
is this the first or last Ab produced affinity? |
IgM: has high avidity b/c of lots of binding sites for Ag
has low affinity though |
|
|
name 4 actions of Ab
|
- neutralize virus infectivity of cells
- opsonize virus and virus infected cells - complement mediated lysis of ENVELOPED viruses - Ab dependent cell mediated cytotoxicity |
|
|
what is ADE
how does it work |
-Ab-dependent enhancement of infection
- non neutralizing Ab can act as receptor for the virus on cells that possess Fc receptors (macrophage) |
|
|
what is complement mediated membrane attack complex, what viruses are affected
is it classical or alternative complement pathway |
-MAC strips envelope from virus
- classical pathway |
|
|
how does the Ab-dependent cell-mediated cytotoxicity pathway work
3 results |
- Fc receptors on surface of NK cells bind to Ab of infected cell
- infected cell goes through apoptosis - cell turn into bleb of Ag content - APC presents bleb to CTL |
|
|
what is a follicular dendritic cell (location, function)
|
- maintains B cell memory by preserving Ag
- located in lymph nodes |
|
|
what effect does HIV have on FDC
|
- destroys FDCs
- immune system regresses to that of neonate, no memory - death due to secondary illness |
|
|
what type of viruses hide in the epidermis
name 3 cancers associated with these: cattle, cattle, sheep and the cofactor involved |
- papillomaviruses
- cattle: alimentary tract carcinoma, bracken fern - cattle: eye and skin carcinoma, sunlight - sheep: skin carcinoma, sunlight |
|
|
how does HIV use APC to cause illness
|
- uses APC as trojan horse to get in close proximity to T cell
- then invades the TH1 cell |
|
|
nomenclature for viruses
5 things |
- virus type
- species - city isolated - year isolated - H and N type of proteins |
|
|
how many Ab binding sites on the influenza HA protein
|
5 sites
|
|
|
Ag drift vs Ag shift
|
- drift: single or small numbers of changes
- shift: replacement of most or all sites, almost like a new virus |
|
|
what is the principle source of new subtypes of influenza virus
|
aquatic birds
|
|
|
what is special about pigs that allows for exchange of viral nucleotides
|
- pigs have both avian and human receptors
- allows for viral mixing |
|
|
what is special about Alpha herpes virus latency
|
- all virus transcription shuts down, except for latency-associated transcripts (LATs)
- by producing only LATs, the immune system cannot track down the virus - cells divide with no evidence of infection - virus replication and virion production resumes after triggering event |
|
|
how does down regulation of MHC I help virus replication
|
- virus will cause downregulation of MHC1 on host cell
- NK cells cant find infected cells due to absence of MHC1 - virus avoids TMC with the CTL |
|
|
what is the goal of vaccination?
|
- not to eliminate the virus, but to eliminate the pathology
|
|
|
vaccine approaches
6 ways (hint, what does the vaccine contain) |
- infection with wild-type virus
- MLV - inactivated virus - subunit formulation - peptide (single epitope) - DNA vaccine |
|
|
what does a minimal vaccine contain
|
- single peptide that can form a TMC
|
|
|
what is a DIVA marker
|
- marker in the vaccine that will differentiate b/w infected and vaccinated animals
|
|
|
inactivated virus or killed whole virus vaccines
- how are the produced - what do they contain |
- virus propagated in culture system
- contain inactivated virus (formalin, heat, irradiation, etc) - have an adjuvant (danger signal) |
|
|
considerations when using killed vaccine
- type of immunity - safety - booster? - onset, duration |
- humoral immunity only, TH2 response (Ab production)
- generally "safer' - booster usually required - slower onset, my not have long duration |
|
|
timing of vaccination
where does the window occur, and for how long |
- presence of maternal Ab will block vaccination
- but need to vaccinate before onset of dz - 2 week window |
|
|
MLV: what does it contain
|
- genetically engineered wild-type w/o the virulence gene
|
|
|
how many doses of MLV vaccine are usually required
|
- single dose for long term protection
|
|
|
why dont MLV vaccines cause infection
- hint: how are they created - does replication occur? - does dz occur? |
- cultured in cells of a different species
- grown in unnatural host - virus can still replicate, but not cause dz |
|
|
what type of immunity is activated by MLV vaccine
|
CMI and humoral immunity
|
|
|
MLV considerations
- why we might not use them: 5 reasons |
- may cause dz (especially in pregnant animals)
- reversion to virulence - can be inactivated (heat, light, disinfectants) - cant differentiate b/w infected and vaccinated - cold chain or on-site preparation |
|
|
1st MLV vaccine
when and what dz |
1950s for Rinderpest
|
|
|
what is in a subunit vaccine
|
- viral proteins separated from the whole virus
- essentially a concentrated killed vaccine |
|
|
advantages of subunit vaccine
2 things |
- increase Ag mass
- incorporate DIVA marker |
|
|
how do we protect neonates from infection
|
- vaccinate the dam
- passive transfer of IgG through colostrum |
|
|
antivirals
ion channel blocking: 2 drugs |
- amantadine
- rimantadine |
|
|
antivirals
polymerase inhibitors: 3 drugs (but name the big one) |
- acyclovir***
- zidovudine - efavirenz |
|
|
effectiveness of viral disinfectant is dependent on what
|
- presence of envelope
|
|
|
common disinfectants:
5 ways |
- alcohol
- bleach - quaternary ammonium compounds (QACs) - oxidative compounds - irradiation |
|
|
name an oxidative compound antiviral
trade name and major virus it inactivates |
- Virkon
- inactivate Parvovirus - considered the gold standard |
|
|
are ds or ss viruses more susceptible to irradiation
|
- ss more susceptible
- if only 1 strand breaks in a ds virus there is still some stability |
|
|
ideal properties of antiviral compounds
4 things |
- broad spectrum
- minimal toxicity to host - minimal side effects - no appearance of resistant viruses after wide spread use |
|
|
amantadine is used for what virus
what protein does it block MOA |
- influenza virus
- blocks M2 protein - prevents UNCOATING of virus, genomic RNA cannot be released |
|
|
side effects of amantadine
Hint: 2 -nergic effects |
- dopaminergic and adrenergic activity
- CNS side effects (nervousness, agitation, insominia) |
|
|
Acyclovir: what does it target
what virus does it target MOA |
- herpes viruses
- targets viral genome replication - acyclovir enters cell and is converted - incorporates into viral genome - results in dsDNA chain termination |
|
|
what 2 things do DNA polymerase (host and viral) look for
what drug blocks one of these |
- template to copy from
- a free 3' hydroxyl group to add next nucleotide to - acyclovir incorporates into viral genome, prevents addition of next nucleotide |
|
|
important properties of acyclovir
4 things |
- drug is only active in infected cell
- higher affinity for viral DNA polymerase (high therapeutic ratio) - irreversible inhibition - low toxicity to non-viral infected cells |
|
|
what is thymidine kinase, what does it do
|
- TK is a virus enzyme that phosphorylates acyclovir in an infected cell
|
|
|
how are viruses resistant to acyclovir
|
- mutations in TK
- TK negative mutants - TK-low producers so the drug isnt converted to active form |
|
|
retrovirus drugs
3 classes |
- nucleoside analog RT inhibitors (RT only produced by the virus)
- non-nucleoside analog RT inhibitors - protease inhibitors (no assembly of virus) |
|
|
nucleoside RT inhibitor
-drug name -what is it - how does it work -specificy at high [ ] |
- AZT
- synthetic thymidine analog - acts as a chain terminator - generally specific for RT, but can inhibit host polymerases at high [ ] |
|
|
ability to make a diagnosis is based on 3 things
|
- clinical observations
- history - develop a differential list |
|
|
what do genotypic detection methods look for
|
- genotype: entire genetic makeup of a virus
- look for presence of specific nucleic acids - nucleic acids or transcriptional RNA |
|
|
phenotypic detection methods
- define phenotype - what do test look for |
- phenotype: entire physical, biochemical, physiological make-up of a virus
- look for presence of the virus - viral structures: filterable particles, electron microscopy, in vitro replication of virus in cells |
|
|
how else can we look for virus (i.e. not the virus itself)
|
- host response: Ab formation
|
|
|
presence of virus
- how to we look for small, filterable particles |
- innoculate filtered particles back into susceptible host
- check for dz |
|
|
electron microscopy
- downsides - Sn |
- cost, technical requirements
- need lots of virus in order to visualize - 10^5 viral particles in sample |
|
|
in vitro replication of viruses in cells is performed how
|
- tissue cultures
|
|
|
tissue explant: define
|
- type of tissue culture
- take tissue slice and place on petri dish - new cell growth onto the dish creates a layer of cells |
|
|
cell suspension: define
|
- break down tissue with enzymes to from a broth
- usually in tubes |
|
|
tissue culture: 2 categories
|
- primary tissue culture
- cell lines |
|
|
primary cell cultures
- lifespan |
- have a finite life span or passage level
- usually less than 10 passages |
|
|
continuous cell lines: definition
- lifespan |
- abnormal and often transformed cell lines
- indefinite lifespan (with proper care) |
|
|
how do you form a passage
|
- have a monolayer and trt with trypsin
- culture goes into single cell suspension - put some into another container - essentially increasing cell numbers in different containers |
|
|
what are we looking for when we visualize a monolayer of cells for virus detection
|
- cytopathic effect
- CPE |
|
|
what is CPE, does it always occur with viral infection, why
|
- CPE is a lytic event for the infected cell
- CPE lacks Sp, not all viruses cause CPE during infection - there are cytopathic and non-cytopathic viruses |
|
what are plaque forming units
|
- PFUs are when you infect a culture cell monolayer
- cover it with soft agar to restrict diffusion - appearance of "plaques" or clear areas where the virus killed the monolayer - can quantify virus particles based on number of clear zones seen |
|
|
what do we view during histopathology to identify presence of virus
2 things |
- non-specific viral structures
- inclusion bodies: accumulation of viral components in cytoplasm of infected cells - syncytia or giant cells: due to fusion protein, cells fuse together |
|
how does the hemagglutination test work
|
- virus causes RBCs to agglutinate
|
|
|
advantages of hemagglutination test
|
- easy to do
- inexpensive |
|
|
disadvantages to hemagglutination test
|
- many variables present: age/fragility of RBC, species, pH
- not virus specific |
|
|
what do we look for in host response to virus
2 things |
- viral proteins
- Ab response |
|
|
2 types of Ab tests
|
- direct
- indirect |
|
|
direct Ab assays use what type of Ab
|
- primary Ab only
- can be either polyclonal or monoclonal |
|
|
how are Ab labeled for direct Ab tests
3 ways, but the most important one is? |
- fluorescent dye
- radiolabeled Ab - enzyme labeled (most common) |
|
|
what does ELISA stand for
|
- enzyme linked immunosorbant assay
|
|
|
how does Direct FA test work
what do you need for comparison |
- fluorescent Ab binds to Ag in infected cells
- requires fluorescent microscope - positive control - negative control |
|
|
which viral test is more specific for detecting a specific virus?
|
FA or fluorescent Ab
|
|
|
what types of tissue can FA testing be used on?
2 tissues |
- tissue culture from suspect culture
- tissue directly from animal |
|
|
what does an indirect Ab test for?
- how many Abs used for test, name them |
-indirect Ab test detects Ab to the specific Ag, not the Ag itself
- uses primary and secondary Abs |
|
|
what 3 things are required in an INDIRECT FA test
|
- infected cells
- specific primary Ab - labeled secondary Ab specific for the primary Ab |
|
|
Indirect FA testing is good for what purpose
|
- identify an unknown virus isolate using a battery of known primary isolates
- test the patients serum for Ab - identify exposure |
|
|
ELISA
MOA properties, uses 4 things |
- indicator Abs bonded to enzymes that catalyze a visible reaction
- visible product - very sensitive - automated - quantify Ag or Ab |
|
|
direct ELISA process
|
- add Ab specific to viral Ag to plate
- add unknown sample containing Ag to plate - add second enzyme-labeled Ab specific to Ag/Ab conjugated - second Ab binds to Ag - color change if positive |
|
|
agar gel immunodiffusion test
- what is this test commonly called - what virus does it test for |
- coggins test
- equine infectious anemia virus (EIA) |
|
what forms in a positive test?
|
- line of precipitation Ag-Ab
|
|
|
what do virus neutralization tests aka serum neutralization tests (SN) detect
|
- test humoral immunity
- identify Abs present in patient serum that neutralize viruses |
|
|
how are Serum neutralization tests done
|
- cell culture, animal, or embryonated egg is innoculated with serum containing Ab and will then be tested with virus
|
|
|
what occurs during SN test if serum has Ab to virus
|
- Ab in serum blocks virus attachment to cells
- infection cant occur |
|
- how is this test read
- what do purple and clear well indicate |
- purple wells indicate live cells
- clear wells indicate that virus has killed cells - wells with a higher dilution (less serum with same virus added) contain a higher Ab conc. |
|
|
what test would we run to detect protective Abs
|
- serum/virus neutralization test
|
|
|
hemagglutination inhibition test tests for what
|
- presence of Ab that prevent virus from causing hemagglutination of RBCs
|
|
|
hemagglutination test
- what do we dilute - what is it testing for |
- dilute virus
- testing to see how much virus is present |
|
|
SN test
- what are we diluting - what is it testing for |
- diluting Ab
- testing for amount of Ab present |
|
|
hemagglutination inhibition test
- what are we diluting - what does it test for |
- diluting Ab
- testing for Ab conc. |
|
|
lateral flow ELISA
- example of viruses tested for 2 viruses |
- parvo virus
- influenza virus type A |
|
|
what does DIVA stand for
|
- Differentiation of Infected or Vaccinated Animals
|
|
western blot testing example for DIVA
|
- when making the vaccine, we would use 1 Ag
- if the animal reacts to other Ag as well, then it is a natural infection and not response to the vaccine |
|
|
what is special about glycoproteins (envelope proteins)
|
- most are host protective
|
