Anti-HIV Antibody Responses Reflect the Quantifiable

HIV Reservoir Size

Sulggi Lee, M.D., Ph.D.Assistant Professor of Medicine

University of California, San FranciscoJuly 20, 2015

Chronic/Latent Viral Infections Lead to Prolonged Antibody Responses

VZV Antibody Half-Life ~ 50 Years

Amanna NEJM 2007

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Time on HAART (years)

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The Size of the HIV Reservoir is Also Stable During Long-Term ART

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Time to eradication> 73.4 years

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Siliciano Nat Med 2003

Anti-HIV Antibody Levels May Distinguish Individuals With Different HIV Reservoir Sizes

Burbelo JID 2014

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Anti-gp41 Levels

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Anti-HIV Antibody Levels May Be Sensitive Measures of the Reservoir Size Over Time

Longitudinal data from Burbelo JID 2014

Anti –gp41 Levels

Median

Years of ART

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Pre-ART

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Hypothesis: Antibody Levels in Blood at Steady-State Reflect Total Body Reservoir Size

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CD4+

Primary Infection

Establishment of Infection in

Lymphoid Tissue

Antibody Production

Current Issues in Measuring HIV Reservoir

• How to measure the success of HIV cure treatments if no scalable, precise assay of the reservoir?

• The HIV reservoir is much larger in tissue than in blood– A reliable measure that reflects the HIV reservoir in tissue?

• Most measures of the HIV reservoir are virologic assays, not cell-based assays measuring host response to virus

Eriksson PLoS Pathogens 2013, Ho Cell 2013, Chun JID 2008, Yukl JID 2010

Study Design

• Aim: Determine whether anti-HIV antibody levels reflect the size of the latent reservoir

• Participants: 61 HIV+ individuals who– Initiated ART during chronic infection– Have been ART-suppressed for at least 3 years

P I V Q N I Q G Q M V H Q A I S P R T L N A W V K V V E E K A F S P E V I P M F S A L S E G A T P Q D L N T M L N T V G G H Q A A M Q M L K E T I N E E A A E W D R V H P V H A G P I A P G Q M R E P R G S D I A G T T S T L Q E Q I G W M T N N P P I P V G E I Y K R W I I L G L N K I V R M Y S P T S I L D I R Q G P K E P F R D Y V D R F Y K T L R A E Q A S Q E V K N W M T E T L L V Q N A N P D C K T I L K A L G P A A T L E E M M T A C Q G V

G G P G H K A R V L*

Luciferase

Luciferase

One letter code for amino acids

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Y Y

YY

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C

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L

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LL = linear epitopeC= conformational epitopes

Novel Luciferase Immunoprecipitation Systems (LIPS) Assay Detects Conformational Antibodies

Question: Are HIV Reservoir Measures Associated with Anti-HIV Antibody Levels?

• gp120• gp41• reverse transcriptase• integrase• protease• matrix• p24

12 Measures of the HIV Reservoir 7 Anti-HIV Antibody Levels

Erikkson PLoS Pathogens 2013, Lewin J Virol 1999, Burbelo JID 2014

Permutation Testing To test the association between

reservoir and antibody measures, adjusted for multiple comparisons

• Total HIV DNA • CD4+ T cells (rtPCR)• PBMCs (ddPCR)• Resting CD4+ T cells (ddPCR)

• Integrated HIV DNA • CD4+ T cells (rtPCR)• PBMCs (aluPCR)• Resting CD4+ T cells (aluPCR)

• 2-LTR HIV DNA • CD4+ T cells (rtPCR)• PBMCs (ddPCR)• Resting CD4+ T cells (ddPCR)

• Unspliced HIV RNA• CD4+ T cells (rtPCR)

• Plasma HIV RNA • Plasma (rtPCR single copy assay)

• Infectious Units per Million • Resting CD4+ T cells (VOA)

Study Participant Characteristics

Characteristics N=61Gender (Male) 59 (96%)*

Age (years) 56 (50-61)

Pre-ART HIV RNA (log10copies/mL) 3.9 (3.5-4.1)

Nadir CD4+ T cell count (cells/mm3) 215 (124-343)

Duration of ART (years) 6 (3-11)

Proximal CD4+ T cell count (cells/mm3) 670 (541-809)

*Number (%) Median and Interquartile Range shown

Measures of the HIV DNA (Total, Integrated) are Correlated with Anti-HIV Antibody Levels

gp120 gp41 RT INT PR MA p24Total HIV DNA

CD4+ T cells (rtPCR) 0.16 -0.03 0.16 0.18 0.17 0.11 -0.08

PBMCs (ddPCR) 0.44 0.48 0.30 0.40 0.40 0.23 0.16

Resting CD4+ T cells (ddPCR) 0.51 0.28 0.62 0.57 0.60 0.54 0.29

Integrated HIV DNA CD4+ T cells (rtPCR) 0.21 0.07 0.20 0.11 0.27 0.06 0.06

PBMCs (aluPCR) 0.80 0.73 0.76 0.70 0.54 0.53 0.41

Resting CD4+ T cells (aluPCR) 0.50 0.72 0.82 0.50 0.25 0.34 0.25

Measures of the “Active” or Replication-Competent Reservoir are Weakly Correlated with Anti-gp120 Levels

gp120 gp41 RT INT PR MA p242-LTR HIV DNA

CD4+ T cells (rtPCR) 0.05 -0.12 -0.10 -0.10 0.14 0.17 -0.07

PBMCs (ddPCR) 0.47 0.26 0.33 0.56 0.46 0.39 0.01

Resting CD4+ T cells (ddPCR) -0.05 0.14 0.09 0.01 0.02 0.09 -0.14

Unspliced HIV RNA CD4+ T cells (rtPCR) 0.40 0.15 0.09 0.12 0.05 0.07 0.10

Plasma HIV RNA Plasma (rtPCR SCA) -0.03 -0.24 -0.15 -0.10 -0.16 -0.06 -0.01

Infectious Units (Per 106) Resting CD4+ T cells (VOA) 0.45 0.43 0.20 0.31 0.30 0.25 0.02

Overall, HIV Reservoir Measures Strongly Correlate with Anti-gp120, -gp41, and -RT Levels

gp120 gp41 RT INT PR MA p24All HIV Reservoir Measures

Correlation (R) 0.80 0.73 0.82 0.70 0.60 0.54 0.41P 0.009 0.04 0.007 0.05 0.20 0.34 0.68

* Adjustment for age, nadir CD4+ T cell count, proximal CD4+ T cell count, years of ART suppression, pre-ART viral load did not significantly alter these results.

Conclusions

• We observed a strong association between measures of the latent HIV reservoir and anti-HIV antibody levels

• Overall, anti-gp120, -gp41, and -RT were most strongly correlated with HIV reservoir size

• Total and integrated HIV DNA were strongly associated with antibody levels against Env and Pol proteins

• Measures of the “active” (CA-US RNA, 2-LTR DNA) and replication-competent (VOA) reservoir were weakly associated with anti-gp120 levels

Remaining Questions• Can viral RNA or proteins be produced in cells with

defective proviruses?– And elicit a host immune response?

• Is there preferential B cell response?– Relative “importance” of Env > Pol > Gag antigens?

• Why are HIV CA-DNA and CA-RNA but not plasma RNA correlated with anti-HIV antibody levels?– Do antibody levels do a good job of quantifying the HIV

tissue reservoir?

Can Anti-HIV Antibody Levels Monitor Response to HIV Cure Strategies?

Antibody Levels Pre-Treatment Antibody Levels Post-Treatment

Acknowledgements• UCSF

– Steven Deeks– Saunak Sen

• NIH/NIDCR– Peter Burbelo

• Johns Hopkins– Robert Siliciano– Janet Siliciano

• University of Melbourne– Sharon Lewin

• UCSD– Douglas Richman– Matthew Strain

• University of Pennsylvania– Una O’Doherty

• University of Sydney– Sarah Palmer

• University of Montreal– Nicolas Chomont– Remi Fromentin