Lecture 14

Question 1

Most of the CD4 cells are depleted in the

Answer 1

GIT

Question 2

True or False

Even with CD4 count above 500, illnesses will occur that can prompt a test for HIV

Answer 2

true

Question 3

CD4+ T cell arise from the ___ _____ _____ in the ___ ____

Answer 3

CD34 progenitor cells n the bone marrow

Question 4

Causes of T cell decline

Ways of Increased infection?

Answer 4

Increased infection:
Direct infection
- GIT&raquo_space;» Blood
- incomplete reverse transcriptase in naive T cells

Indirect effects:
Syncitium formation
Apoptosis
Immune activation
Lymph node fibrosis

I

Question 5

Causes of T cell decline

Ways of Impaired production?

Answer 5

Infection of:

Thymus
CD34+ progenitor cells

Question 6

Nef is..

Answer 6

An accessory protein that down regulates MHC II - limits the amount of antigen presentation

Question 7

Which HLA types are associated with a good prognosis?

Answer 7

B13, B27, B51, B57

Question 8

Which HLA types are associated with a rapid disease progression?

Answer 8

A23, B37, B49

Question 9

NK cells are impaired in _____ and ______

Answer 9

number and function

Question 10

What HIV- induced immunopathology are related to Monocytes and Macrophages?

Answer 10

Defects in chemotaxis
Inability to promote T cell proliferation
Defects in Fc receptor function

Question 11

What causes immune activation?

Answer 11

Mucosal depletion of CD4 t cells

Leads to more activation of Toll-like receptor 4 for bacterial

Activation of immate immune response
( increased plasma IFN - alpha)

Expansion of CMV-specific activated t cells (Cytomegalovirus specific response)

Loss of T regulatory cells (which normally down-regulates immune response)

Question 12

Some non-pathogenic models (Sooty Mangabey), will not undergo CD4 decline, Immune activation and have low LPS when infeced with HIV/SIV - why?

Answer 12

you maintain CD4 T cells in GIT, which reduces the downstream effects

Question 13

Chemokine receptor antagonists block?

Answer 13

CCR5/CXCR5 receptors

Question 14

What people are dying from now are referred to as …

Why?

Answer 14

non-AIDS deaths

CV disease more prevalent, as well as liver/renal/bone, malignancies

Drugs have side efects
still some immune dysfunction

Question 15

Why is there variability in the amount of CD4 cells Recover once patient is on Hart?

Answer 15

Viral factors:
CXCR4
co-infection with other viruses eg. Hep C virus

Host factors
genetic factors
residual immune activation
Thymus function - age

Question 16

What are the Biomedical ways of HIV prevention?

Answer 16

Vaccines
Circumcision
Microbicides
Anit-retroviral therapy
Treat sexually transmitted infection

Question 17

What are some Vaccine approaches and their problems?

Answer 17

Recombinant proteins: Good antibody, poor T cell response

DNA vaccines: Good T cell response, poor antibody response

Live Vector viruses: good T cell responses

• found to be not effective
• possible increase in risk fo infection

Live attenuated virus: Unsafe

Question 18

which Vaccine methods show promise?

Answer 18

Prime boost: DNA & protein or replicating vector (have been found to be partially statistically significant)

Broadly neutralising antibodies

CMV vectors

Question 19

Broadly neutralising antibodies can “neutalise” a large number of viuses

where are they directed?

Answer 19

Against highly conserved regions of envelope that are “hidden”

Can be machined using technolgy to make B cells that produce specific antibodies in vitro

Question 20

CMV vectors have some unique properties, what are they?

Answer 20

Unconventional MHC-II restricted CD8+ T cells

Breadth of epitope recognition

Promiscuity