Intro Prt 2 Flashcards
7 HUMAN ONCOVIRUSES
Human papilloma virus
Epstein barr virus
Hepatitis B virus
Human herpes virus
Merkel cell polyomavirus
HTLV
Hepatitis C virus
→ benign & malignant warts
• Types___,____ = cervical cancer
• Human papillomaviruses (HPV)
16 & 18
- infectious mononucleosis, Burkitt’s lymphoma, Hodgkin’s lymphoma & nasopharyngeal carcinoma
• Epstein-Barr virus (EBV)
hepatocellular carcinoma
• Hepatitis B virus (HBV)
Kaposi’s sarcoma
• Human herpesvirus 8
→ Merkel cell carcinoma, neuroectodermal tumor
• Merkel cell polyomavirus
leukemia & lymphoma
Human T-cell Lymphotropic Virus
hepatocellular carcinoma
• Hepatitis C virus
- has only a single molecule of circular RNA
- No capsid or envelope; affect only plant diseases
Viroids
- Infectious; no detectable nucleic acid, only a single type of protein molecule; highly resistant to heat, formaldehyde, UV
- transmissible spongiform encephalopathies (kuru, Creutzfeldt-Jakob, scrapie in sheep/goats)
Prions
- Circular, ssRNA dependent on viruses for replication and encapsidation; does not code for proteins; affect crops
Virusoids
- satellite’, viroid-like, larger than viroids
Virusoids
Nucleic acid & proteins
- Require a “helper virus” to replicate (ex. Hepa D virus)
Defective Viruses
• recombinant viral particles with its core/backbone and envelope proteins derived from different viruses, unable to produce surface protein on their own
Pseudovirions
- Viruses that infect and replicate in the bacteria or the archaea; do not attach eukaryotic cells.
Bacteriophages
- Results in progeny virus that carries traits not found together in either parent
Recombination
ex. Influenza virus - the formation of recombinant is caused by reassortment of individual genome fragments
Recombination
• One virus provides a gene product in which the second is defective,
allowing the 2nd virus to grow; genotypes remain unchanged
Complementation
• Genome of a virus becomes randomly incorporated within capsid proteins specified by a different virus;
not a stable genetic change
Phenotypic Mixing/Masking or transcapsidation
- Infection with 2 viruses leads to an inhibition of multiplication of one of the viruses (block receptors for adsorption, compete with replication apparatus, induce cell to produce inhibitors or interferons
Interference
- Cell or tissue cultures or fertile eggs - for analyses of viral replication and protein function
2.______ - de novo from live animal cells, for primary isolation, studies of pathogenesis
Animal culture
Cell cultures:
a.________ -cells isolated from human or animal tissue using enzymatic or mechanical methods; adherent or suspension types.
Ex.
Primary monkey kidney cells, human embryonic kidney
Primary cells
b._______ - cells that have been continually passaged over a long period of time, finite or continuous cell lines.
______\-derived from diploid cell lines or from malignant tissue, ex. Hep-2 cells (human epidermoid carcinoma), HeLa cells (cervical carcinoma)
Cell lines
Continuous cell lines
is commonly used to describe the density of adherent cells and it is used as a measure of their proliferation.
•_____ confluency means that 10% of the surface the dish or flask used is covered with cells
•____ means that it is entirely covered
Cell culture
10%
100%
The level of confluency is important as the cells change their growth with changing densities.
• Low density cells (10-20%) usually grow slower than 50% confluent cells.
• If the plate is completely grown by cells, they tend to grow much slower again.
DETECTION OF VIRUS-INFECTED CELLS
- Development of CYTOPATIC EFFECTS (CPE)
- Appearance of a virus-encoded protein
- Detection of virus
- Hemadsorption
• Cell lysis or necrosis
• Rapid rounding of cells
• Inclusion body formation
• Focal areas of fused cells - syncytia
• Giant cell formation
• Cytoplasmic vacuolization
Development of CYTOPATIC EFFECTS (CPE) (morphologic changes in the cells)
Appearance of a virus-encoded protein,
ex.______ of influenza virus. Specific antisera can be used for detection.
Hemagglutinin
Detection of virus-specific nucleic acid. Molecular based assays -___
PCR
- adsorption of erythrocytes to infected cells,
ex.
Parainfluenza, influenza
Hemadsorption
Direct
droplet or aerosol infection (eg,4);
influenza
rhinovirus
measles
small pox
Direct
sexual contact (eg,4)
papillomavirus
hepatitis B
herpes simplex type 2
human immunodeficiency virus
Direct
by hand-mouth, hand-eye, or mouth-mouth contact (eg,2);
herpes simplex
Epstein-Barr virus
Direct
exchange of contaminated blood (eg,3).
hepatitis B
hepatitis C
human immunodeficiency virus
Indirect transmission by the
fecal-oral route (eg,3) or by
fomites (eg,2).
enteroviruses, rotaviruses, and hepatitis A
Norwalk virus and rhinovirus
animal to animal, with humans an accidental host.
Spread may be by bite (_____) or by droplet or aerosol infection from rodent-contaminated quarters (eg,2).
rabies
arenaviruses and hantaviruses
Transmission by means of an arthropod vector (eg, arboviruses, now classified primarily as 3)
togaviruses, flaviviruses, and bunyaviruses
MOT
(eg, influenza, rhinovirus, measles, and small pox);
droplet or aerosol infection
MOT
(eg, papillomavirus, hepatitis B, herpes simplex type 2, and human immunodeficiency virus);
sexual contact
MOT
(eg, herpes simplex and Epstein-Barr virus);
hand-mouth, hand-eye, or mouth-mouth contact
MOT
(eg, hepatitis B, hepatitis C, and human immunodeficiency virus).
exchange of contaminated blood
MOT
______(eg, enteroviruses, rotaviruses, and hepatitis A) or by
_______(eg, Norwalk virus and rhinovirus).
fecal-oral route
fomites
Transmission from animal to animal, with humans an accidental host. Spread may be by______ (rabies) or by droplet or aerosol infection from______-contaminated quarters (eg, arenaviruses and hantaviruses).
bite
rodent
MOT
(eg, arboviruses, now classified primarily as togaviruses, flaviviruses, and bunyaviruses)
arthropod vector
• Self-limiting
• Symptoms of sudden onset or last a short time
• Ex. rhinoviruses
Acute, nonpersistent infection
Acute, nonpersistent infection
Ex.
Rhinovirus
• Virus persists in an occult/hidden/cryptic form
• No new virus
• Intermittent flare-ups clinically
• Ex. Herpesviruses, chickenpox
• Latent infection
Latent infection ex
Herpesviruses, chickenpox
Replicating virus continuously detected often at low levels
• Mild or no symptoms
• Associated with certain types of cancer or progressive degenerative disease
• Ex. EBV, hepatitis B
Chronic or persistent infection
Chronic ex
EBV, hepatitis B
• Long incubation periods
• Slow, progressive diseases
• Ex. HIV
Slow Infection
is commonly used to describe the density of adherent cells and it is used as a measure of their proliferation.
•_____ confluency means that 10% of the surface the dish or flask used is covered with cells
•____ means that it is entirely covered
Cell culture
10%
100%
