Functional Cure for HIV: Lymphoid T cell Dynamics and PD-1 Immunotherapy 公开

Mylvaganam, Geetha Hanna (2016)

Permanent URL: https://etd.library.emory.edu/concern/etds/h702q6667?locale=zh
Published

Abstract

Human immunodeficiency virus (HIV) has emerged as one of the most devastating global health burdens in history with approximately 36 million individuals infected worldwide. The introduction of anti-retroviral therapy (ART) has greatly enhanced viral control and the quality of life for individuals living with HIV, but ART remains a life long therapy due to latently infected CD4 T cells that are seeded early during primary infection. The latent HIV reservoir is directly responsible for viral resurgence post treatment interruption. Due to the limited success in generating a highly effective prophylactic vaccine for HIV and with 15 million and a growing number of HIV infected individuals on ART, researchers have re-directed their focus towards generating a more feasible approach to treating HIV, termed a "functional cure". The key to achieving a functional cure for HIV requires reduction/elimination of viral reservoirs and restoration of functional anti-viral CD8 T cells. The viral reservoirs are concentrated at lymphoid sites and thus there is a need for understanding the dynamics of virus-infected CD4 T cells and anti-viral CD8 T cells in the lymphoid tissue during chronic infection. Using a macaque model system of SIVmac251 pathogenesis, our studies revealed critical findings. Firstly, we observed that PD-1hi Tfh cells are aberrantly enriched in the lymph nodes (LN) and rectal mucosa of chronically SIV infected macaques and contribute to ongoing viral replication and production. Secondly, we identified a novel subset of germinal center infiltrating CXCR5+ SIV specific CD8 T cells that rapidly expand in vaccinated SIV controllers, can limit the expansion of virally infected Tfh, and are associated with enhanced viral control. Lastly, immunomodulation of the PD-1 pathway prior to and during the initiation phase of ART in a therapeutic SIV/ART macaque trial demonstrated significantly enhanced proliferation, cytotoxic potential, and polyfunctionality of anti-viral CD8 T cells resulting in markedly faster suppression of virus replication following the initiation of ART. Together, these findings further our understanding of some of the fundamental aspects of basic HIV/SIV biology and provide insight into novel therapeutic interventions that can be administered in combination with ART.

Table of Contents

Table of Contents Abstract Dedication Acknowledgements Chapter 1: Introduction -------------------------------------------------------------- 1

History and Global Burden of HIV/AIDS ----------------------------------------- 1

Transmission and Pathogenesis ----------------------------------------------------- 1

ART and Viral Reservoirs ----------------------------------------------------------- 6

Immune Drivers of Viral Persistence ----------------------------------------------- 9

Immune Response to HIV ----------------------------------------------------------- 12

Innate immune response --------------------------------------------------- 12

Adaptive immune response ------------------------------------------------ 12

Humoral Immunity ------------------------------------------------ 13

Cell mediated immunity ------------------------------------------- 14

T Follicular helper cells and HIV ------------------------ 17

CD8 T cells and HIV ------------------------------------- 20

Immune Exhaustion and Check-point Inhibition --------------------------------- 22

Summary -------------------------------------------------------------- 27 Chapter 2: Diminished Viral Control during ----------------------------------------------- 30

SIV Infection is Associated with Aberrant

PD-1hi CD4 T cell Enrichment in the

Lymphoid Follicles of the Rectal Mucosa

Figure 2.1. Phenotypic characterization ofPD-1+-------------------------------- 51

subsets in the blood, lymph node (LN), and rectum

of healthy rhesus macaques (RM) Figure 2.2. Characterization of PD-1hi CD4 T cells in the ------------------------ 52

LN and rectum of chronically SIV infected vaccine-controller

and non-controller RM

Figure 2.3. CXCR5 expression and localization of ------------------------------- 53

PD-1hi CD4 T cells of chronically SIV infected

vaccine-controller and non-controller RM

Figure 2.4. Phenotypic characterization of PD-1hi -------------------------------- 54

CD4 T cells in the LN and rectum of chronically

SIV infected vaccine-controller and non-controller RM

Figure 2.5. Phenotypic characterization of CCR5 -------------------------------- 56

expression and infection status of PD-1hi CD4 T cells

in the LN and rectum of chronically SIV infected

vaccine-controller and non-controller RM

Figure 2.6. Association between anti-viral CD8 T cells --------------------------- 58

and PD-1hi CD4 T cells in the LN following SIV infection

Figure 2.7. Accumulation of PD-1hi CD4 T cells --------------------------------- 59

in the LN of SIV infected non-controlling RM

Figure 2.8. BCL-2 expression on Naïve and --------------------------------------- 60

Memory CD4 T cells in the LN and Rectum

of SIV infected macaques

Figure 2.9. Accumulation of SIV infected Tfh ----------------------------------- 61

within the LN and Rectal mucosa of SIV infected

Non-controlling RM Chapter 3: Follicular Anti-viral CD8 T cells Contribute ----------------------------------- 62

to Enhanced Control of Pathogenic SIV

Figure 3.1. Rapid expansion of CXCR5+ SIV specific --------------------------- 79

CD8 T cells is associated with enhanced

control of chronic SIV infection

Figure 3.2. CXCR5+ SIV specific CD8 T cells are -------------------------------- 80

more polyfunctional than CXCR5- SIV specific CD8 T cells

in the blood

Figure 3.3. CXCR5+ SIV-specific CD8 T cells are localized -------------------- 81

in the germinal centers (GC) of vaccinated controllers

and limit Tfh expansion in vitro

Figure 3.4. Global gene expression analysis revealed distinct ------------------- 82

gene expression profile for CXCR5+ SIV specific CD8 T cells

Figure 3.5. Correlations between the percentage of ------------------------------ 83

CXCR5+ GagCM9+ CD8 T cells at week 2-3 and

week 12-24 post SIV infection and set-point VL

Figure 3.6. Percentage of CXCR5+ GagCM9 CD8 T cells ----------------------- 84

in unvaccinated animals at week 12-24 post SIV infection

inversely correlates with set-point viral load

Figure 3.7. Representative FACS plots from a controller ------------------------ 85

and non-controller RM at week 24 post SIV infection

Figure 3.8. Representative immunofluorescence staining ------------------------ 86

of CD8 T cells in LN sections from SIV+ non-controller

and SIV+ vaccine controller RM at week 24 and

week 2-3 post SIV infection Figure 3.9. Representative in situ tetramer staining images ---------------------- 87

of MLN, spleen and rectal tissue of SIV infected controller RM

Figure 3.10. Induction of perforin and -------------------------------------------- 88

granzyme co-expression on CXCR5+ and - CD8 T cells

co-cultured with P11c antigen pulsed Tfh

Figure 3.11. Representative histogram plots showing ---------------------------- 89

the expression of phenotypic markers on

naïve and memory CXCR5+ and CXCR5-

GagCM9 CD8 T cells, and Tfh cells

Table 2. Cohort of SIV infected rhesus macaques used for sample collection - 90

Figure 3.12. Greater Frequency and Function ------------------------------------ 91

of Germinal Center (GC) Infiltrating CXCR5+ CD8 T Cells

During Controlled SIV Infection Chapter 4: In vivo PD-1 blockade as a Therapeutic --------------------------------------- 92 Adjuvant to Antiretroviral Treatment Figure 4.1. In vivo PD-1 ART trial design ----------------------------------------- 114

Figure 4.2. Rapid and discernable PD-1 blockade in vivo ----------------------- 115

Figure 4.3. PD-1 blockade results in enhanced ----------------------------------- 116

in vivo proliferationof CD4 and CD8 T cells

Figure 4.4. PD-1 blockade results in enhanced ----------------------------------- 117

polyfunctionality of SIV specific CD8 T cells

Figure 4.5. PD-1 blockade results in enhanced ----------------------------------- 118

functional quality of CD8 T cells

Figure 4.6. In vivo PD-1 blockade synergizes ------------------------------------ 119

with ART resulting in increased viral suppression

Figure 4.7. In vivo PD-1 blockade enhances -------------------------------------- 120

Th17 reconstitution in the rectal mucosa under

suppressive ART

Figure 4.8. Partial reconstitution of CD4 T cells ---------------------------------- 121

in the blood and rectal mucosa of ART treated macaques

Figure 4.9. Levels of cell associated Gag DNA ----------------------------------- 122

within memory CD4 T cell subsets in PD-1 treated and

control groups during suppressive ART

Chapter 5: Discussion -------------------------------------------------------------- 123

Early ART Initiation -------------------------------------------------------------- 125

Targeting the Tfh Viral Reservoir -------------------------------------------------- 127

HIV Sanctuary - Exposing the Germinal Center Reservoir ---------------------- 131

Modulating Anti-viral Immunity under ART ------------------------------------- 134

Biologicals -------------------------------------------------------------- 134

Therapeutic Vaccines ------------------------------------------------------ 135

Cytokine based therapies and Latency Reversing Drugs (LRA's) ------ 138

Conclusions -------------------------------------------------------------- 141

Figure 5.1 Potential mechanisms of viral control ------------------------ 142

by therapeutic vaccines

References ------------------------------------------------------------------------------------- 143

About this Dissertation

Rights statement
  • Permission granted by the author to include this thesis or dissertation in this repository. All rights reserved by the author. Please contact the author for information regarding the reproduction and use of this thesis or dissertation.
School
Department
Degree
Submission
Language
  • English
Research field
关键词
Committee Chair / Thesis Advisor
Committee Members
最新修改

Primary PDF

Supplemental Files