HIV

Question 1

HIV virus

Answer 1

causes AIDS
belongs to retroviridae family
spherical
enveloped
2 identical ss +ve sense RNA

Question 2

HIV causes?

Answer 2

AIDS

Question 3

how many strands of RNA?

Answer 3

2 identical ss+ve sense RNA

Question 4

HIV makeups?

Answer 4

ss +ve sense RNA
nucleoprotein-P7
nucleocapsid -P24
outer matrix protein-P17
lipid envelop
transmembrane/fusion gp- gp41
surface/attachment/spikes gp-gp120

Question 5

three enzymes present in HIV

Answer 5

reverse polymerase enzyme
protease
intergrase

Question 6

reverse polymerase function

Answer 6

when the virus enter into the host cell, it convert the RNA into DS DNA

Question 7

SS RNA is converted into?

Answer 7

DS DNA

Question 8

name the 3 HIV genome?

Answer 8

gag gene- core/shell of the virus

env gene-synthesis of envelope (gp120)

pol gene-reverse transcriptase /other enzymes (integrase, protease)

Question 9

HIV resistance?

Answer 9

thermolabile, 10m @60d

seconds @ 100 d

Question 10

how long can HIV survive at room temp in dried blood?

Answer 10

7 days

Question 11

treatment of HIV contaminated instruments

Answer 11

glutaraldehyde

Question 12

mode of transmission

Answer 12

sexual contact
blood transfusion
mother to fetus
iv drug users

Question 13

pathogenesis of HIV

Answer 13

Infection is transmitted through- the blood or tissues of a person.
The receptor for the virus is the CD4 antigen.
Therefore the virus may infect any cell bearing the CD4 antigen on the surface
primarily in CD4 T lymphocytes,
Some other immune cells also posses the CD4 marker - 5 – 10% B lymphocytes,
10 -20% Monocytes – Macrophages
including

-Specialised macrophages such as alveolar macrophages in the lungs.
-langerhans cells in the dermis.
-Glial cells ,Microglia in CNS
-Follicular dendritic cells from tonsils – can be infected
without CD4 involvement.

The viral surface spike (gp120) specifically bind with CD4
receptor along with co-receptor molecules
- CXCR4 for T-cell
- CCR5 for Macrophagic cells

After attachment, the viral fusion protein gp41 help the virus to fuse with host cell membrane. After fusion, the HIV genome is uncoated and internalised into the host cell.

Now, the S.S+ve sense RNA -(reverse transcriptase)-S.S DNA-D.S.DNA-(integrate)-integrated with host cell DNA and become latency.

From time – time, lytic infection is initiated

                             Progeny virions

The long & variable incubation is due to this latency.

Question 14

in infected person, HIV can be isolated from

Answer 14

• blood,
  - lymphocytes,
  
  • cell-free plasma,
  • semen,
  • cervical secretions,
    
    • saliva,
  • tears,
  • urine and breast milk.

Question 15

primary pathogenic mechanism of HIV

Answer 15

damage to the CD4 cells

CD4 cells decrease in number and T4:T8 ratio is reversed

Question 16

HIV can suppress the function of a cell without structural changes , yes or no?

Answer 16

yes

Question 17

the infected T4 cells do not release? damping effect of CMI?

Answer 17

lymphokines
interleukin-2
gamma interferon

Question 18

major damage of HIV?

Answer 18

cellular immunity and humoral immunity

Question 19

Helper T cell activity is essential for B cell function, particularly in responding to thymus dependent Antigens.
YES OR NO?

Answer 19

YES

Question 20

polyclonal activation of B cells leads to?

Answer 20

hypergammaglobulinemia called useless immunoglobulin

Question 21

why is it called useless immunoglobulin?

Answer 21

all classes of Ig are raised to irrelevant antigens &

autoantibodies (responsible for type 3 hypersensitivity).

Question 22

is monocyte-macrophage function is affected? how?

Answer 22

YES,due to lack of secretion of activating factors-chemotaxis, antigen presentation & intracellular killing.

Question 23

The NK cells & Tc cells activity is also affected in the
chronic condition. YES OR NO?

Answer 23

YES