Infectious Disease -- HIV Packet Additions #1

Question 1

p24

Role in pathogenesis and monitoring

Answer 1

Core protein

Screening antibodies are made to this protein

Question 2

gp120

Role in pathogenesis and monitoring

Answer 2

Coat protein which binds to CD4

Binds with CCR5 or CXCR4 to fuse with the cell

Question 3

Identify and describe the three major stages of HIV

Answer 3

Primary Infection -Acute HIV, virus dissemination and seeding, rapid blood CD4 drop
Clinical Latency - Slowly dropping Blood CD4s
AIDS - Constitutional Symptoms, Opportunistic Disease, Death

Question 4

Can HIV be transmitted by insect bite?

Answer 4

Nope

Question 5

What are SEVI?

Answer 5

Semen derived enhancers of viral infection

Prostatic acid phosphates that assemble into amyloid like fibers

Question 6

Effect of Circumcision on HIV transmission…

Answer 6

Increased transmission with uncircumsized.
Caused by increased presence of dendritic cells in the foreskin or retention of infected vaginal/rectal fluids under the foreskin

Question 7

Seroconversion following HIV needle stick is ___%

Answer 7

0.3%

Question 8

List CD4+ cells that HIV can bind to

Answer 8

T cells, NK cells, Monocytes, Macrophages, dendritic cells, glial cells

Question 9

CCR5 is expressed primarily on…

HIV specific for CCR5 is called….

Answer 9

Monocytes and Lymphocytes

Monocytotrophic (M-Trophic)

Question 10

CXCR4 is expressed primarily on…

HIV specific for CXCR4 is called…

Answer 10

Only T lymphocytes

Lymphotropic (T-Trophic)

Question 11

Why does the switch to CXCR4 so rapidly escalate T cell destruction?

Answer 11

It binds a wider range of T cell types, including naive T cells and thymocytes. Also, lose some of the CD8 cell blocking

Question 12

How do activated CD8 cells partly block viral uptake of HIV?

Answer 12

Production of RANTES, MIP-1a, MIP1b
These bind CCR5 and block the virus uptake
Once CXCR4, nothing it can do.

Question 13

Explain HIV viral uptake into a cell

Answer 13

Gp120 binds CD4, then the coreceptor
gp41 binds, then undergoes conformational change
Fusion peptide generated that fuses virus+cell membrane

Question 14

Describe the process of Lymph Node burn out

Answer 14

Loss of CD4 T cells in the gut leads to progressive, systemic inflammatory infection. Initially, this will cause lymphadenopathy and hypergammaglobulinemia, corresponding to germinal center hyperplasia. Later, all of the inflamm. cytokines will cause architectural and fxnal disruption of LN with cell loss and fibrosis.

Question 15

Describe initial CD4 T cell loss

Answer 15

Initially large numbers are lost from LN, modest drop in blood levels
Usually mostly lost from Peyer’s patches

Question 16

Reasons other than CD8 lysis and viral proliferation for CD4 loss in infection?

Answer 16

• Apop. of uninfected CD4 in LN from TLR induced entry to S phase
• Blocked fxn by gp120 binding (no antigen presenting)
• Fusion into syncytia, where they die

Question 17

What type of cells are never recovered by HAART? Significance of this?

Answer 17

HIV-specific CD4 cells

HIV specific CD4s are probably the first to die

Question 18

Progression of Immune Cell Loss

Answer 18

1. Loss of fxnal CD4, no new cell/Ab mediated responses
2. Loss of memory Bs and T cell precursors
3. Loss of CD8
4. Polyclonal B cell activation with no new responses
5. Autoimmune Destruction

Question 19

Viral load of an HIV patient should be assessed at least every..

Answer 19

3 months

Question 20

Early in infections, HIV viral particles can be seen…

Answer 20

Follicular mantle cells

Dendritic Processes

Question 21

Describe acute retroviral syndrome

Answer 21

• High levels of viral replication, viremia, and widespread N seeding
• Controlled by host anti-viral immune response
• Develops within 3-6 weeks and lasts 2-4 weeks

Question 22

Describe prolonged latent infection

Answer 22

Patient may remain well
Slow immune deterioration
Progression indicated by steady state viremia

Question 23

Describe Accelerated Progressive Immunodeficiency

Answer 23

Opportunistic Infections, Dementia, Neoplasms

Question 24

Three latent infections that tend to be reactivated in AIDS

Answer 24

Toxoplasmosis
TB
Herpes Zoster

Question 25

Explain kaposi’s sarcoma

Answer 25

HHV8 associated

Masses of proliferative spindle-shaped cells form blood channels (make endo, smooth musc, perictes)

Question 26

Three forms of Non-Hodgkin’s Lymphoma

Answer 26

Systemic (80%)
Primary CNS Lymphomas
Body Cavity Based Lymphomas

Question 27

Ways considered to boost anti-viral response without destruction of HIV specific CD4 cells

Answer 27

HAART + Interleukins
Passive Transfer of HIV-specific T cells
RANTES+MIP
Abs against cell debris or rapidly mutating epitopes