T/F: HIV isn’t actually oncogenic, it’s immune suppressive
True
T/F: cancer from a viral infection requires a persistent infection and usually develops decades after an acute infection
True
HTLV (human T lymphotropic virus) is of _______ family.
Retroviridae
HTLV genome? Capsid? Envelope?
RNA +
Diploid
Reverse transcriptase
Enveloped
Icosahedral capsid
HTLV-1: think ____ protein
TAX
HTLV infection causing ________ leukemia/lymphoma. Could present with:
Adult T cell
Lymphadenopathy, maculopapular skin lesions, lytic bone lesion, hypercalcemia
Blood smear of Adult T cell leukemia/lymphoma appears ________
Like a flower with indented nuclei with condensed chromatin and basophilic cytoplasms
HTLV infects _____ T cells
CD 4+
T/F: HTLV-1 is just like HIV in that they are both retroviruses that infect CD4+ T cell and both replicate its genome quickly inside the cell
False; all is true until the last part of the statement. HTLV-1 replicates slowly so to maintain genetic stability whereas HIV replicates quickly with less stability than HTLV-1
How can HTLV-1 lead to lymphoma?
It doesn’t cause the T cells to die, but instead it pushes CD4 T cells to proliferate and transform
Endemic areas of HTLV-1:
Japan
Caribbean
Equatorial Africa and south America
T/F: HTLV-1 is a human only virus
True
Transmitted primarily by breastfeeding
Also: sexual intercourse, IVDU, contaminated blood products
Tax is an _______ found in ______that regulates _____
Oncoprotein
HTLV-1
Viral mRNA transcription and translation (basically functions in viral production by inducing expression of IL-2 and IL-2 receptors)
What is the function of Rex protein in HTLV-1?
Rex helps get unspliced viral RNAs out of the nucleus
What is the HTLV-1 viral protein that limits Tax oncoprotein activity by promoting cell survival and is necessary for maintaining transformation?
HBZ
Host cell receptor for HTLV-1:
GLUT-1 receptor
HTLV-1 replication cycle (initial): _____ inserted inside the cytoplasm and _______ is activated to convert viral ssRNA into __________, then makes complementary DNA strand.
Capsid
Reverse transcriptase
Single-stranded DNA
HTLV-1 replication cycle (integration): dsDNA transported into host cell ________, using ________ to get incorporated into cellular chromosomal DNA. Due to similar nature to host DNA, viral dsDNA gets transcribed and translated into viral proteins.
Nucleus
Viral integrase
HTLV-1 replication cycle (release): once enough _____ is made, unspliced viral RNA is released from the ____ and gets packaged up into its ______ and bud from the infected cell to gain its ____
Viral protein
Nucleus
Capsid coat
Envelope
T/F: HTLV-1 genome contain oncogenes and integrate into sites near cellular oncogenes like other oncovirus.
False; HTLV-1 genome does not contain oncogene, instead they promote oncogenesis by promoting synthesis of IL2 (uncontrolled T cell growth and eventual malignant transformation of the cell
EBV is of _____ family
Herpesviridae
What are the three most common EBV infections:
Infectious mononucleosis
Nasopharyngeal carcinoma
African Burkitt Lymphoma
EBV genome, capsid, envelope?
dsDNA linear genome
icosahedral capsid
envelope
Where does EBV replicate their genome?
Inside host nucleus. EBV makes their own DNA polymerase to replicate
EBV can gain access to blood and infect B cells using CD____ as the host cell receptor for entry
CD21
T/F: EBV-infected B lymphocytes undergo polyclonal activation and these B cells produce heterophile antibodies and the stimulate the production of atypical lymphocytes (CD 8 or NK origin= not B cells)
True
Herpesviruses get their envelope from:
Nuclear membrane
T/F: atypical lymphocytes seen in mono blood smear are B lymphocytes because EBV infects B cells
False; they are atypical lymphocytes, of CD8 and NK origin
How is EBV diagnosed? How to tell latency?
antibodies against viral capsid antigen (VCA)
Look for EBNA (nuclear antigen) if latency is established
How does EBV infected B-cells become immortalized?
EBV tolerates a translocation of c-myc and this helps progress the cell towards being cancerous
Remember c-myc is an oncogene that promotes cell growth (as seen in Burkitt lymphoma)
Serology where IgM and IgG VCA are detected means _____ infections. Where IgG is present but no IgM means ______ infections
Acute
Months of infection (EBNA will be detected because latency has established)
A positive EBV-EBNA IgG (nuclear antigen) means ______
Associated with past infection
EBNA means latency has esablished
What are Downey cells?
Atypical T cells seen in EBV. (CD 8 T cell) looks like ballerina skirts
Author
lykthrnn
ID
348568
Card Set
Viral Causes of Leukemia and Lymphoma Microbiology
