ORAL REVALIDA 3

Question 1

What family does HIV belong to?

Answer 1

Retroviridae

Question 2

What disease does HIV cause?

Answer 2

Acquired Immunodeficiency Syndrome (AIDS)

Question 3

What are the two main HIV serogroups?

Answer 3

• HIV-1 (predominant, found worldwide).
• HIV-2 (mainly in West Africa).

Question 4

What are the three subtypes of HIV-1?

Answer 4

M, N, and O, with M being the major subtype.

Question 5

What cells does HIV bind to?

Answer 5

CD4+ T helper cells, monocytes, and macrophages

Question 6

What role do co-receptors play in HIV infection?

Answer 6

They assist viral binding to host cells.

Question 7

How does HIV enter the host cell?

Answer 7

It penetrates the plasma membrane, releasing its RNA.

Question 8

What enzyme transcribes HIV RNA into DNA?

Answer 8

Reverse transcriptase.

Question 9

How is viral DNA integrated into the host genome?

Answer 9

Using the viral enzyme integrase.

Question 10

How does HIV replicate inside the host cell?

Answer 10

1. Viral DNA is transcribed into mRNA.
   
   2. mRNA is translated into viral proteins.
   3. New viruses bud from the host cell.

Question 11

What is the effect of HIV replication on the immune system?

Answer 11

It kills infected T helper cells, reducing their number over time.

Question 12

When do HIV antibodies first appear?

Answer 12

Around 12 weeks after infection.

Question 13

What tests detect these initial antibodies?

Answer 13

ELISA and Western blot.

Question 14

What are neutralizing antibodies, and when do they appear

Answer 14

• Antibodies that interfere with viral infection.
• Appear 1 year after infection.

Question 15

Why is the immune system unable to eliminate HIV?

Answer 15

HIV undergoes antigenic variation, allowing it to evade the immune response.

Question 16

What happens to CD4+ T helper cells as HIV progresses?

Answer 16

They decrease, leading to worsening immune deficiency

Question 17

Why is the loss of T helper cells critical?

Answer 17

They are essential for both humoral and cellular immunity.

Question 18

How does HIV affect the CD4:CD8 ratio?

Answer 18

It decreases from the normal 2:1 ratio.

Question 19

How does HIV affect other immune cells?

Answer 19

• Decreased natural killer (NK) cell activity.
• Defective monocyte and macrophage chemotaxis.
• Increased release of interleukin-1 and cachectin by monocytes.

Question 20

How is HIV-1 transmitted?

Answer 20

Through:
• Unprotected sex
• Contaminated blood/products
• Contaminated needles
• Perinatal transmission

Question 21

AIDS in the us

Answer 21

AIDSVis the leading cause of death in people aged 20–35 in the US

Question 22

What are the symptoms of acute HIV infection?

Answer 22

Usually asymptomatic, but may resemble infectious mononucleosis (IM).

Question 23

What is clinical latency in HIV?

Answer 23

A stage where the virus replicates in lymphoid tissue without major symptoms.

Question 24

What is AIDS-related complex (ARC)?

Answer 24

A stage where opportunistic infections (e.g., Candida, herpes simplex, CMV) begin as T cells decline

Question 25

What defines full-blown AIDS?

Answer 25

Severe CD4+ T cell depletion and life-threatening opportunistic infections/cancers, including: • Esophageal candidiasis • Cryptococcosis • Cytomegalovirus (CMV) & herpes simplex infections • Pneumocystis jiroveci pneumonia (PJP) • Kaposi’s sarcoma

Question 26

How is the severity of HIV/AIDS staged?

Answer 26

By CD4+ T cell counts and the presence of opportunistic infections.

Question 27

What is the primary screening test for HIV?

Answer 27

ELISA, which detects HIV antibodies and antigens.

Question 28

How is an HIV diagnosis confirmed?

Answer 28

By a Western blot or immunofluorescence assay.

Question 29

What criteria make a Western blot positive?

Answer 29

The presence of at least two of the following bands: • p24 • gp41 • gp120/gp160

Question 30

What molecular tests detect HIV?

Answer 30

• Genetic probes detect replicating viruses. • RT-PCR (Reverse Transcriptase PCR) detects HIV-1 and HIV-2 nucleic acids. • Indirect immunofluorescence assay detects HIV antigen in infected cells.

Question 31

What is the main HIV treatment?

Answer 31

Antiretroviral therapy (ART), including Zidovudine (Retrovir).

Question 32

How does Zidovudine help?

Answer 32

• Increases survival time • Decreases mortality

Question 33

What are the roles of GP-120 and GP-41 inhibitors in HIV treatment?

Answer 33

• GP-120 inhibitors: Prevent virus attachment and entry into cells. • GP-41 inhibitors: Block virus fusion with immune cells.

Question 34

Does ART cure HIV?

Answer 34

No, it suppresses the virus but does not eliminate it. The virus can still hide in tissues (latency phase) and reactivate if treatment stops.

Question 35

What are the six classes of antiretroviral drugs?

Answer 35

1. Attachment Inhibitors 2. Nucleoside Reverse Transcriptase Inhibitors (NRTIs) 3. Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs) 4. Protease Inhibitors 5. Integrase Inhibitors 6. Pharmacokinetic Enhancers (Boosters)

Question 36

What are the key HIV prevention strategies?

Answer 36

• Modifying sexual behavior (e.g., using condoms, reducing partners) • Protecting blood supply (e.g., donor screening, heating plasma at 68°C for 24 hours) • Encouraging self-referral among high-risk groups

Question 37

Why is an HIV vaccine difficult to develop?

Answer 37

• Rapid mutations create multiple strains. • HIV hides in immune cells, making it hard to target. • The virus infects the very immune cells a vaccine would stimulate.