elisa

Question 1

AIDS etiologic agent

Answer 1

hiv type 1. HIV-1 contains an RNA genome and the RNA

dependent DNA polymerase also termed reverse transcriptase.

Question 2

HIV is

unique in some of its properties since

Answer 2

it specifically targets the immune
system, is very immunoevasive, forms significant amounts of progeny virus
in vivo during the later stages of the disease and can be transmitted
during sexual activity.

Question 3

The viral proteins are identified by

Answer 3

the
prefix gp (glycoprotein) or p (protein) followed by a number indicating
the approximate molecular weight in kilodaltons.

Question 4

hiv particle structure

Answer 4

The HIV viral particle is surrounded by a lipid bilayer derived from the host
cell membrane during budding. Beneath the bilayer is a capsid. Within this shell is the viral core.

Question 5

lipid bilayer

Answer 5

The lipid bilayer contains gp 160, gp 120 and gp

41. The gp 41 anchors gp 120 in the bilayer

Question 6

capsid

Answer 6

Beneath the bilayer is a capsid consisting of p17

and p18.

Question 7

viral core

Answer 7

The
walls of the core consists of p24 and p25. within: 
-  two identical RNA molecules 9000
nucleotides in length
- Hydrogen bonded to each
viral RNA is a cellular tRNA molecule
- 50 molecules of
reverse transcriptase.

Question 8

An individual can be infected with HIV through

Answer 8

an abrasion in a mucosal
surface (e.g. genital and rectal walls), a blood transfusion or by intravenous
injection with a contaminated needle.

Question 9

During the early

stages of infection in an immunocompetent person __. however

Answer 9

the HIV virus elicits
humoral and cellular immunity responses that result in a variety of circulating
IgG molecules directed at several viral epitopes. However, since the
virus has a high mutation rate the variants survive and produce progeny
having a similar capacity to escape immunosurveillance.

Question 10

__ This is believed to be the main mechanism

of HIV immunoevasion.

Answer 10

Unlike other cellular DNA polymerases, HIV DNA polymerase (reverse
transcriptase) has a high error rate. These frequent mutations continually
change the viral protein epitopes.

Question 11

The most important target for the virus are

Answer 11

hematopoietic cells such as bone marrow derived monocytes, myelocytes
and immune system lymphocytes.

Question 12

__ ultimately produce the

most profound clinical consequences.

Answer 12

Infection of immune system

effector cells such as T cells and macrophages

Question 13

binding process

Answer 13

gp 120 binds to the CD4 receptors
on the surface of T helper (TH) cells. These receptors are membrane
bound glycoproteins involved in T cell maturation from precursor cells. TH
cells are required for the body’s overall immunological responses. The
viral lipid bilayer fuses with that of the cell’s membranes and the viral
protein capsid becomes internalized via receptor mediated endocytosis.
Subsequently, the rest of the CD4 receptors are internalized and gp 120
appears on the T cell surface.

Question 14

binding process

Answer 14

gp 120 binds to the CD4 receptors
on the surface of T helper (TH) cells. These receptors are membrane
bound glycoproteins involved in T cell maturation from precursor cells. TH
cells are required for the body’s overall immunological responses. The
viral lipid bilayer fuses with that of the cell’s membranes and the viral
protein capsid becomes internalized via receptor mediated endocytosis.
Subsequently, the rest of the CD4 receptors are internalized and gp 120
appears on the T cell surface.

Question 15

trna molecule

Answer 15

acts as the primer for the first strand

synthesis.

Question 16

RNAse H activity

Answer 16

The reverse transcriptase, RNAse H activity, degrades the RNA
strand of the RNA-DNA duplex and the polymerase activity synthesizes a
complementary DNA strand.

Question 17

hiv integrase

Answer 17

The DNA reverse transcripts (copy DNA)
migrate into the cell nucleus where they become covalently integrated
into the cellular genomic DNA. The integration is catalyzed by the HIV
integrase.

Question 18

LTRs

Answer 18

The copy DNA integrates via specific, self-complimentary
sequences at both ends called long terminal repeats (LTRs). These
sequences also have important functions in viral transcription.

Question 19

provirus

Answer 19

The
integrated copy DNA is called proviral DNA or the provirus. The provirus
enters a period of latency that can last for several years.

Question 20

provirus

Answer 20

The
integrated copy DNA is called proviral DNA or the provirus. The provirus
enters a period of latency that can last for several years.

Question 21

protease inhibitor

Answer 21

inhibit protein processing

Question 22

macrophages

Answer 22

Macrophages are circulating monocytes and are involved in the nonspecific
engulfment of foreign material and normal cellular debris. These
materials are degraded in the lysosomes of the cells. Peptides from
foreign degraded proteins are transported to the macrophage surface
where they remain bound by specialized receptors.
- Immunologically
inactive TH cells interact with these surface bound antigen-receptor
complexes which enables them to become fully activated.