Laboratory Activity 17 – Determination of Anti-HIV 1/2 Flashcards
1
Q
(AIDS); human retrovirus
A
HIV-1 and 2
2
Q
(+) ss-RNA
A
Retroviruses
3
Q
reverse transcriptase
A
Retroviruses
4
Q
This enzyme enables the virus to convert viral RNA to DNA in contrast to the normal process of transcription, where DNA is converted to RNA
A
reverse transcriptase
5
Q
HIV infects
A
CD4+ T cells
macrophages
dendritic cells
6
Q
HIV Mode of Transmission
A
Sexual contact
Mother to infant
Needle sharing by drug users
Blood or blood product transfusion Transplantation of tissues or organs
Contact with contaminated blood/body fluids
7
Q
Human T cell lymphotropic virus type III (HTLV-III)
Lymphadenopathyassociated virus (LAV)
AIDS-associated retrovirus (ARV)
A
HIV-1
8
Q
Endemic in West Africa; less pathogenic and has a lower rate of transmission
A
HIV-2
9
Q
Group-specific antigen
A
gag
10
Q
Polymerase
A
pol
11
Q
Envelope
A
env
12
Q
Transactivator
A
tat
13
Q
Regulator of viral expression
A
rev
14
Q
Viral infectivity
A
vif
15
Q
Viral protein R
A
vpr
16
Q
Viral protein U
A
vpu
17
Q
Negative-regulation factor
A
nef
18
Q
Core proteins and matrix proteins
A
gag
19
Q
Reverse transcriptase, protease, and integrase enzymes
A
pol
20
Q
Transmembrane glycoproteins
A
env
21
Q
Positive regulator of transcription
A
tat
22
Q
Allows export of unspliced and partially spliced transcripts from the nucleus
A
rev
23
Q
Affects particle infectivity
A
vif
24
Q
Transport of DNA to the nucleus; augments virion
roduction; arrests cell cycle
A
vpr
25
Promotes intracellular degradation of CD4 and
nhances the release of virus from the cell membrane
vpu
26
Augments viral replication in vivo and in vitro; down- regulates CD4 and MHC class II
nef
27
codes for gp160/120 and gp41
HSV 1
28
codes for gp140 and gp34
HSV 2
29
codes for p 55 → p15, p17, and p24
Note: sor codes for p24
HSV 1
30
codes for p26
HSV 2
31
Transcribes RNA to DNA
Reverse transcriptase
32
inserts viral DNA to host cell’s DNA
Integrase
33
cleaves structural protein
RNase and Protease
34
May last from many months to years
Primary stage
35
also known as AIDS-related complex (ARC)
Intermediate stage
36
Infected persons may experience an initial lu-like illness, and then remain symptomatic or exhibit only chronic ymphadenopathy for many years.
Primary stage
37
There are physical symptoms, but no opportunistic infections
Intermediate stage
38
is usually seen within 2 to 10 years after initial infection with the HIV
Final stage
39
Pneumocystis jiroveci, Mycobacterium tuberculosis, and fungal infections
Pneumonia
40
oral candidiasis; thrush
Candida albicans
41
diarrhea and weight loss
Cryptosporidia and microsporidia
42
Enteric bacterial infection
Salmonella and Campylobacter
43
Toxoplasma gondii
cysts in the brain
44
Cryptococcus neoformans
meningitis
45
Cytomegalovirus
inflammation of retina, brain and spinal cord
46
multi-focal tumor of endothelial cells
Kaposi’s sarcoma
47
The CD4:CD8 ratio
reduced from normal
48
CD4-positive T-cell counts
decreased
49
CD4-positive T-cell function
impaired
50
B-cell activation
abnormal
51
Macrophage function
impaired
52
NK cell function
impaired
53
Viral antigen is coated on a solid support → patient serum added → after incubation and washing, enzyme-labeled antihuman globulin (AHG) is added followed by substrate
Enzyme-linked immunosorbent assay (ELISA)
54
HIV antigen is adsorbed onto carrier particles → the particles agglutinate in the presence of antibody
Slide agglutination test
55
Anti-HIV bound to a solid support is incubated with serum → after washing, enzyme-labeled anti-HIV-1 is added followed by substrate
p24 antigen test (HIV-1 Ag)
56
p24 antigen precedes antibody by several weeks; positives must be confirmed by neutralization assay
p24 antigen test (HIV-1 Ag)
57
a. Screening Tests
Enzyme-linked immunosorbent assay (ELISA)
Slide agglutination test
p24 antigen test (HIV-1 Ag)
58
b. Confirmatory Tests
Western blot testing
Immunofluorescence assay (IFA)
Radioimmunoprecipitation Assay (RIPA)
59
A lysate of HIV antigen is separated into components by electrophoresis and transferred to nitrocellulose paper → the resulting blot is cut into strips and reacted with serum → labeled antihuman globulin is added
Western blot testing
60
HIV infection is indicated by reactivity in two (2) of the following bands:
61
o Antibody test: Serum is incubated with virally infected cells on a glass slide → fluorescence-labeled antihuman globulin is added
62
o Antigen test: Patient cells are fixed to a slide and incubated with HIV-specific antiserum
Immunofluorescence assay (IFA)
63
Employs a soluble second antibody to precipitate the bound antigen
Radioimmunoprecipitation Assay (RIPA)
64
o IgM antibody against the p24 core protein usually develops within [?] after infection
6 to 8 weeks
65
o Within weeks, IgG antibodies against p24 appear, as do antibodies against [?] (i.e., gp160, gp120, gp41) and [?] (i.e., p31, p51, p66)
envelope gene products
polymerase gene products
66
o The HIV isolation technique can detect antigens before antibodies develop and can be used to monitor antiviral treatment
67
• The patient’s monocytes are stimulated and grown in culture ® the culture supernatant can be tested for the presence of antigens
68
• A modified enzyme-linked immunosorbent assay (ELISA) can be performed on plasma, serum, cerebrospinal fluid (CSF), and culture fluids to detect the presence of HIV antigens
69
• Immunofluorescence assay (IFA) can be used to detect HIV antigens
70
• Virus grown on culture
71
• Expensive, time-consuming and hazardous; not routinely performed
72
can be used to detect viral RNA
In situ hybridization and filter, hybridization
73
o Cells from peripheral blood and lymph nodes can be used
In situ hybridization and filter, hybridization
74
can be used to detect viral DNA in infected cells
Southern blot hybridization
75
can be used to amplify both RNA and DNA, which provides extremely sensitive systems for RNA and DNA detection
Polymerase chain reaction (PCR) techniques
76
o Viral DNA from infected cells is amplified, then identified using labeled probes
Polymerase chain reaction (PCR) techniques
77
o Extremely sensitive technique
Polymerase chain reaction (PCR) techniques
78
Tests to Stage and Monitor HIV
• CD4 T cell count
• HIV-1 viral load assay
79
o Purposes: Used to predict disease progression, determine when to start antiretroviral therapy, monitor response to therapy
Tests to Stage and Monitor HIV
80
o Test 2-8 weeks after the start of therapy and then every 3-4 months (the same assay should be used to assess changes)
Tests to Stage and Monitor HIV
81
Tests to Stage and Monitor HIV
o Methods include:
• Reverse transcriptase-polymerase chain reaction (RT-PCR)
• Branched DNA (bDNA)
• Nucleic acid sequence-based amplification (NASBA)
