potential mucosal immune mechanisms for increased hiv susceptibility in women infected by herpes...
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Potential mucosal immune mechanisms for increased HIV susceptibility in women
infected by Herpes simplex type 2
Dr. Anu Rebbapragada
University of Toronto
Anu Rebbapragada, Charles Wachihi, Chris Pettengell, Sherzana Sunderji, Sanja Huibner, Anthony Sheung, George Moussa, Anthony
Mazzuli, Walter Jaoko, Blake Ball, Keith Fowke, Francis Plummer and Rupert Kaul
HIV infects >40 million globally, mostly through sexual transmission, and most are now in women
Mucosal vaccine and microbicide trials will need to monitor genital immunology and must consider that:
•Globally, genital co-infections are “the norm”
•CMV infects 50-90% of adults - more in Sub Saharan Africa (SSA)
•HSV2 infects 20-60% of adults - more in SSA, more in women
•Bacterial vaginosis, HPV, trichomoniasis: also very common
Interactions at the Mucosal Front
General population:• associated with a >3 fold increase in HIV acquisition by women, even in the absence of genital ulcers (Freeman E, 2006; Wald A, 2004)
•In Sub-saharan African Women: HSV2 prevalence ~ 50%
HIV and HSV2A Dangerous Liaison
Core Transmitter Groups:
• HSV2 has been associated with 6-fold increase in HIV acquisition in Nairobi female sex workers (FSWs; JAMA, 2004)
• In FSWs: HSV2 prevalence group exceeds 75%
HSV2 may drive HIV transmission
Wald A, Herpes. 2004.
In regions of high HSV2 seroprevalance:
• Mathematical modeling predicts 50% of new HIV cases directly attributed to HSV2
Research Questions
How does HSV2 infection increase HIV acquisition?
• Is this simply due to epithelial micro-ulceration?
• Or through negative effects on the female genital tract (FGT) immune milieu?
What is the potential immune basis of enhanced HIV susceptibility?
HSV2 Study: Mucosal Sampling
For all women:
• Cytokines/chemokine levels in CVL by CBA (BD)
• Immune Genes expression levels: QPCR (cytobrush)
• Endocervical cell populations by flow cytometry (scraper)• Mucosal Lymphocytes: CCR5+/CD69+ CD4+ T cells
• Mucosal Dendritic cells: CD1a+ iDC, DC-SIGN+ iDC, TLR9+ iDC
• HIV, CMV serology; HSV2 serology (Kalon)
• HSV2 DNA from swab (Artus)
• CMV DNA from CVL (Artus)
• HIV-1 RNA from swab (Versant)
• Cross-sectional survey during 2004-2005
• Female sex workers from Pumwani, Nairobi
102 FSWs screened for possible study enrollment
91 FSWs enrolled
11 FSWs taking ARV excluded
HIV uninfected (N = 55) HIV infected (N = 36)
HSV2 infected
(42/55, 76%)
HSV2 uninfected
(13/55, 24%)
HSV2 infected
(36/36, 100%)
**LR = 14.5P<0.001
0/42 (0%)
Shedding HSV2
10/36 (26%)
Shedding HSV2
**LR = 16.5P<0.001
Endocervical Cell Populations
CD1a
DC
-SIG
N
1 0
0
1 0
1
1 0
2
1 0
3
1 0
4
1 0
0
1 0
1
1 0
2
1 0
3
1 0
4
1 0
0
1 0
1
1 0
2
1 0
3
1 0
4
1 0
0
1 0
1
1 0
2
1 0
3
1 0
4
CD3
CD
4
Autofluorescence
0 5 0 1 0 0 1 5 0 2 0 0 2 5 0
1 0
0
1 0
1
1 0
2
1 0
3
1 0
4
Sid
e sc
atte
r
Forward scatter
Granular Cells
Lymphocytes
Impact of HSV2 status on FGT immune milieu
Lymphocyte Populations
CD4+ CCR5+CD4+
CD69+CD4+
%CD69+
* ****
0
500
1000
1500
2000
20%
40%
60%
80%
0%
HSV2 uninfected
HSV2 infected
Immune cell populations
Dendritic Cell Populations
Impact of HSV2 status on FGT immune milieu
**CD1a+ DC-SIGN+
iDC%DC-SIGN+
iDC
*0
20%
40%
60%
80%
0%
HSV2 uninfected
HSV2 infected
20000
Immune cell populations
40000
60000
80000
20%
One possible model for mucosal HIV-HSV2 synergy
HSV2 infection
DC-SIGN+ iDCCCR5+ CD4 T cells
HSV2 reactivation& shedding
HIV infection
DC-SIGN+ iDC TLR9+ iDC
HSV2 proteinstransactivate HIV-LTR
HIV shedding
Conclusions
1. Powerful epidemiologic synergy between HIV and HSV2:
• HIV infected FSWs more likely to be HSV2 infected and shed HSV2.
4. Novel Strategies to reduce HIV transmission:
• Microbicides targeting DC-SIGN and/or CCR5
3. Interaction between HIV and HSV2 in the genital mucosa
• Powerful immunological negative synergy
2. HIV target cells increased in FGT of HSV2 infected FSWs:
• 10 fold increase in DC-SIGN+ CD1a+ immature dendritic cells
• 3 fold increase in CCR5+ CD4+ T cells
Dr.Rupert Kaul
Kaul lab: Prameet Sheth, Chris Pettengel, Sanja Huibner, Bolette Bossen, Kamnoosh Shahabi, Sherzana Sunderji, Anthony Sheung
University of Toronto: Mario Ostrowski, Sandy Der
University of Manitoba: Blake Ball, Keith Fowke, Frank Plummer
University of Nairobi: Joshua Kimani, Charles Wachihi, Elizabeth Ngugi, Walter Jaoko, Jane Kamene, Nyakio Chinga, Anne Miangi
Funding: NIH, CIHR, CANVAC, Canada Research Chair