Block 3 Flashcards
What viruses have natural onclytic tendencies
Reovirus
Parvovirus
Coxsackie
CPR (The essentials)
others:
genetically manipulated viruses to kill cancer cells
HSV
vaccinia
polio
adeno
How is polyomavirus special
circular dsDNA
early genes ==> large T antigen and small T anritgen
late genes ==> VP1-4
ALSO AFTER BEING ENDOCYTOSE GOES TO ER BEFORE NUCLEUS
BK virus
4 serotypes
disease upon immunosuppression
infection at young age
persistent in proximal renal tubular cells but can infect other T cells or other cells
10% of renal transplant polyomavirus associated nephorpaty
THINK TRANSPLANT IMMUNOSUPRESSION
10-25% BMT hemoraghic cystitis
cancer in animal modles not humans
JC virus
1 serotype
infections HUMAN GLIAL CELLS VIA SEROTONIN RECEPTOR
disease upon immunosupression like BK
persists in kidney, lymphocytes, bonne marrow cells
PML progressive multifocal leukoencephalopaty
DEMYELINATING DISEASE
cancer in animal models not humans
MCC
only PyV that can cause cancer in humans
starting during childhood
no cell culture systems
fast growing, PAINLESS, DOME SHAPED
RISK IN IMMUNOCOMPROMSIED, OLD PEOPLE SUN EXPSOED AREAS
integration into host chromosome in most MCC and mutation of LgT antigen in DDB
what causes cancer in MCC
integration into host chromosome and mutation in LgT
LgT expression in 98% of MCC
mutation in DBD of LgT
recall that LgT antigen (of early genes) consists of DNA binding domain, J domain (DNa replication), LXLCME, helicase domain
screen these viruses in pre engraftment
HBV HCV HIV CMV EBV syphilis
pre engraftment infections due to immunosupression
respriatoyr viruses
enteric viruses
HHV reactiv
HSV reactivation
post engraftment infections
30-100 days
CMV
adeno
HHV 6
RSV, IFV< PIV, MPV, RV (CA respiratory)
Retroviral mediated oncogenesis
non transforming and transforming
transforming oncogenesis
an oncogene is introduced
a MUTATED COPY OF A CELL GENE INVOLVD IN GROWTH CONTROL
infection introduces the mutated ONCOGENE ==> rapid tumor onset
Oncogenes include Src in the sarcoma virus
non transforming oncogenesis
ACTIVATING HOST GENES or INACTIVATING
dont transform culture cells
6 months - 1 year
promoter insertion enhancer insertion (virus inserts in wrong directly opposite to gene but U3 is a strong viral enhancer that inappropriately turns on the cell promoter)
most viruses containing oncognes are
DEFECCTIVE
bc oncogene replaces some necessary viral genes
Basis for hiv strain tropism
envelope sequence of diff HIV have PREFERENCE FOR DIFF CO RECEPTORS
env interacts with CD4
induces CONFORMATIONAL CHANGE IN ENV
EXPOSES CO RECEPTOR BINDING SITE
gp41 FUSION DOMAINS EXPOSED. FUSION DOMAINS ENTER CELL MEMBRANE
co receptor engaged, gp41 snaps back
CAN YOU BLOCK SNAP BACK??? to block fusion
T20 blocks snapback of gp41
hiv infection pathogenesis
enters at mucosal surface
gets to the DC. DC brings HIV to the T cells in LYMPH NODES AND INFECTS T CELLS
replication within T cells, spills into circulation (viremia)
asymptomatic phase, FDC traps the virus and keeps viremia low BUT GALT is where REPLICATION IS HAPPENING
DC CAN CONTAIN THE VIRUS, BUT MOST REPLICATION IS STILL HAPPENING IN THE DLN
acute retroviral syndrome
sudden burst of virus production with decline in CD4 T cells
early vigorous CTL and humoral response helps clear viremia (along with FDC)
controlled it appears but high level persists in LN/GALT
HIV clinical features
progression of HIV
CD4:CD8 ratio, CD4 counts, viral load (RNA)
patients with a low set point have better prognosis
hiv diagnosis
Ab ELISA (detects ab to virus, initial screening) only 4-6 weeks after infection does it show positive. not detecting efore
Ag elisa (p24 capsid) 7-14 days after infection
WB ==> confifirmatory. detects HIV protein
rtPCR quantitatves RNA IN BLOOD
CAN DETECT BEFORE SEROCONVERSION
gauges viral load in ASYMPTOMATIC PATIENTS with low titers
ideal pathogen for vaccine
1) few serotypes
2) limitated mutageness of antigens
3) natural immunity after infection
4) acute infection that can be CLEARED FROM MOST IMMUNOCOMPETNET PEOPLE
How to make live vaccine
1) passage of a virus in animal host ca n make a weaker virus (Yellow fever)
2) isoalted virus from a diff species but provides cross protection
Cowpox/vaccinia to immunize smallpox
3) passage a pathogen in TC at a lower temp ==> select mutants that can’t replicate at BT (warmer)
aka flumist
inactiated virus
generates immune response BUT CAN’T MAKE INFECTIOUS VIRIONS
HAV, HBV, HPV, influenza, polio (salk), rabies
salk vs sabin admin
salk REQUIRES PARENTERAL
sabin ==> oral. rep in intestines
think salking teenager hates their parents (parenteral)
rash with central umbilication
COWPOX
pustules, vesicular
Roseola
fever, seizures then mobilliform rash (resembes measles)
Descending rash
measles and rubella.
rubella has more posterior cervical lymphoadeopathy
the only RNA virus that is double stranded
Reovirus
the only DNA virus that is single stranded
parvovirus
why is hepadnavirus special
circular, partially ds DNA virus
replicates in nucleus and cytoplasm
RNA all enveloped except
the ones that cause gut infections
reovirus
calcivirus (norovirus)
picornavirus
all positive sense RNA are icosahdral except
coronavirus (helical)
SEGMENTED GENOMES thus can
undergo reassortment
bunyavirus, orthomyxo, areno, reovirus
BOAR
paramyxovirus shape
paranomal mixer has HELICAL DECORATIONS HANGING FROM THE PARTY
helical shape
enveloped (ghost wearing a ghost cloak)
requirement of viruses. the main goal
MAKE MORE MRNA and new viral genomes
so need to make +mRNA from -mRNA
genomic type defines nuclei acid detection and diagnostics
baltimore classification
genomic type
6 classes -
plaque forming assay
plaque represents spread initiatited by a single infectious unit (pfu)