Retrovirus, AIDS, and Tumor Viruses Flashcards Preview

Micro and Immuno - Exam 2 > Retrovirus, AIDS, and Tumor Viruses > Flashcards

Flashcards in Retrovirus, AIDS, and Tumor Viruses Deck (49)
Loading flashcards...
1
Q

Retrovirus Genome

A

(+)ssRNA

2
Q

Retrovirus Virion

A

Enveloped

3
Q

Retrovirus Incubation

A

Varies

4
Q

Retrovirus Strains

A

A-Type
B-Type
C-Type
D-Type

5
Q

Retrovirus A-Type

A

Shell and hollow center

Immature particle

6
Q

Retrovirus B-Type

A

Circular nucleus

Eccentric location

7
Q

Retrovirus C-type

A

Circular nucleus

Central location

8
Q

Retrovirus D-Type

A

Cylindrical nucleus

Central location

9
Q

Retrovirus Replication

A

As it enters the cell, it undergoes reverse transcription - ssRNA genome becomes dsDNA
The viral dsDNA integrates itself into the host, making it a provirus

10
Q

Reverse Transcription

A

Defining Feature of Retroviruses
Occurs within a large complex similar to nucleocapsid
Infection cannot progress if reverse transcription does not occur

11
Q

What initiates Reverse Transcription

A

Initiates once the nucleocapsid is inside the cytoplasm

12
Q

What is necessary for Reverse Transcription to occur?

A

Need higher levels of NTP

Low levels of NTP prevent reverse trasncriptase

13
Q

What happens to Revers Transcription between genome copies

A

Silent when the copies are identical

Many different recombinations can occur when different genomes are in the virion

14
Q

What is necessary for Integration of a Retrovirus to occur

A

The retrovirus must access the nucleus

15
Q

When does a Retrovirus access the nucleus?

A

During Mitosis

It can infect non-dividing cells, but the mechanism is unknown

16
Q

Integration

A

3’ end of processing dsDNA atacks the target DNA, creating a nick
Host repairs the nick, but in doing so, integrates the viral DNA
Integration is permanent

17
Q

Endogenous provirus

A

If a retrovirus is integrated into the germ-line

18
Q

Retrovirus Complications

A

Integration may disrupt host genes, causing diseases such as cancer

19
Q

Retrovirus Symptoms

A

Many infections are benign

But they can cause significant disease

20
Q

Slow Retrovirus

A

Effect is like high-level mutagenesis

Eventually results in tumorigenesis

21
Q

Cytopathic Retrovirus

A

Minority of Retroviruses carry cytopathic genes

Cause tissue damage directly

22
Q

Actute Transforming Viruses

A

Induce rapid tumor formation
Carry host genes - mitogenic or antiapoptotic
Often replication defective because host gene replaces an essential gene

23
Q

Human T-Cell Leukemia Virus Genome

A

(+)ssRNA

24
Q

Human T-Cell Leukemia Virus Virion

A

Enveloped

25
Q

What are the two diseases of Human T-Cell Leukemia Virus?

A

Adult T-Cell Lymphoma/Leukemia (ATLL)

HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP)

26
Q

Human T-Cell Leukemia Virus Incubation

A

ATLL - 30-50 years

HAM/TSP - 3 years

27
Q

What are the types of Human T-Cell Leukemia Virus?

A

Types 1, 2, 3, 4

Type 1 is the most common in humans

28
Q

Human T-Cell Leukemia Virus Replication

A

Cytoplasm

29
Q

ATLL Symptoms

A

Tumors, Immunosuppression

30
Q

HAM/TSP Symptoms

A

Bladder issues, LL back pain, Leg weakness, ED, and impotence

31
Q

Human T-Cell Leukemia Virus Transmission

A

Person to person:

  • Mother-to child via breastfeeding
  • Sharing needles
  • Blood transfusions
  • Sex
32
Q

How does Human T-Cell Leukemia Virus spread in the body?

A

Via infected cells being in contact with naive cells

33
Q

ATLL

A

Occurs in 2-4% of cases of HTLV-1
Antigen activation triggers transcription of provirus
Virus tax protein and others stimulate cell proliferation
Cells become transformed generating tumors

34
Q

HAM/TSP

A

Occurs in 1-2% of cases
Following transfusions
Infected T-cells enter the CNS
-activates astrocytes and microglial cells
-recruit inflammatory cells and cause further tissue damage

35
Q

Human T-Cell Leukemia Virus Prevalence

A

Millions of people worldwide

36
Q

Human T-Cell Leukemia Virus Prevention

A

Eliminate breastfeeding for HTLV-1 positive mothers

Increased screening for blood products

37
Q

Human T-Cell Leukemia Virus Treatment

A

ATLL - treat the leukemia/lymphoma with chemotherapy regardless of HTLV infetions
HAM/TSP - corticosteroids, interferon yields temporary relief of symptoms

38
Q

HIV Genome

A

(+)ssRNA

39
Q

HIV Virion

A

Enveloped

40
Q

HIV Incubation

A

HIV - 2 weeks

AIDS - 6 months-25 years

41
Q

HIV Strains

A

Two main types in humans - Types 1 and 2

42
Q

HIV Replication

A

In the Cytoplasm

43
Q

HIV immune response inhibition

A

Targets memory T-cells (CD4+)

44
Q

HIV Symptoms

A

Immunosuppression

Wasting - weight loss

45
Q

HIV Transmission

A

Sex
Needle sharing
Mother to infant

46
Q

HIV Complications

A

Immunosuppression and AIDS development

47
Q

HIV Prevalence

A

Worldwide pandemic

Highest impact is in Sub-Saharan Africa

48
Q

HIV Prevention

A

Sexual behavior and protection

Blood screening

49
Q

HIV Treatment

A

Antiviral treatments

  • Nucleoside reverse transcriptase inhibitor
  • Protease inhibitors
  • Non-nucleoside RT inhibitor
  • Highly active antiretroviral therapy