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A Long-Term Nonprogressor’s Journey into HIV-1 Disease: Association with Escape from Cellular Immune Control Kimdar S. Kemal, Ph.D. Wadsworth Center Albany, New York. MRC, Human Immunology Unit, Oxford, UK Tara Beattie Tao Dong Julian Sutton Hongbing Yang Yang Chun Peng
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A Long-Term Nonprogressor’s Journey into HIV-1 Disease: Association with Escape from Cellular Immune Control Kimdar S. Kemal, Ph.D. Wadsworth Center Albany, New York
MRC, Human Immunology Unit, Oxford, UK Tara Beattie Tao Dong Julian Sutton Hongbing Yang Yang Chun Peng Sarah Rowland-Jones U. Toronto Rupert Kaul Wadsworth Center Harold Burger Barbara Weiser Sean Philpott Los Alamos National Laboratory Carla Kuiken Dorothy Lang U. Pennsylvania Ronald Collman COLLABORATORS
BACKGROUND • A small proportion (1-5%) of patients remain free of HIV-related disease without antiretroviral therapy for at least 10 years of infection. • Such individuals are known as long term nonprogressors (LTNP).
Background cont. • Transition from LTNP infection to HIV-1 disease presents an opportunity to investigate pathogenesis and disease progression in a defined immunogenetic background.
PATIENT • We studied a Caucasian male,who was exposed to HIV-1 in May 1982 by sexual contact with a man who later developed AIDS. • He remained disease-free without ART for over 18 years; however he recently showed signs of progression.
Objective • To examine the virologic and cellular immunologic aspects of the transition from LTNP to progressive disease.
METHODS • We obtained full-length and serial HIV-1 genomic RNA sequences from plasma.
Methods cont. • A total of 50 autologous peptide epitopes (37 HLA class I and 13 class II peptides), based on the patient’s viral sequences and described for his HLA alleles, were screened by using IFN- ELISpot assays.
Methods cont. • The assays were performed using PBMC obtained before and after disease progression.
RESULTS Virology • No clearly attenuating mutations or deletions in the patient’s HIV-1 sequences were identified. • The length of the V2 region increased from 44/45 amino acids in 1998-2001 to 51/52 amino acids in 2002-2004 .
HIV-1 gp120, V2 sequence alignments V2 insertion siteLength pNL4-3 FFYKLDIVPI ~~~~~~~~~~ ~~~~~~~~~~ DNTSYRLISC 38 WC3-498 L..R..V... KNNSTSY~~~ ~~~~~~~~~~ -.......N. 44 WC3-999 L..R..V... GN~~~~~DTA SF~~~~~~~~ -.N.....N. 44 WC3-901 L..R..V..L KN~~~~~DSA SYY~~~~~~~ -.......N. 45 WC3-602 L..R..V... GN~~~~~DTA SFNNSYNNSY --N.....N. 51 WC3-1202 L..R..VT.. KN~~~~~DEN NTSEGNNTS~ ........N. 52 WC3-603 L..R..V... GN~~~~~DTN SFNNSYNNSY .--.....N. 51 WC3-704 L..R..V... EN~~~~~DTN SFNNSYNNSY .--.....N. 51 . Identity with pNL4-3 strain, - deletions, ~ absence of insertions
Results cont. • Throughout the course of infection the patient’s virus utilized the CCR5 coreceptor. • Insertions in the HIV-1 gp120, V2 domain, have been described to enhance CCR5 coreceptor usage.
Results cont. • Immunology • Before disease progression, PBMC from this patient made detectable IFN- responses to 8 class I (CD8) and 3 class II (CD4) epitopes targeting 4 HIV-1 genes (env, gag, pol and nef).
Results cont. • After disease progression, his PBMC made detectable IFN- response to 12 class I (CD8) and 4 class II (CD4) epitopes spanning 4 genes (env, gag, pol, and nef).
CD4+ and CD8+ T cell responses before and after disease progression. CD4+ T cell responses DR Int KR15 DR p24 GI15 DR Int QR15 DR p24 KY15 DR gp160 TR13 2002 2004 B8 p24 GI9 B8 p17 GL8 B8 p17 EL9 CD8+ T cell responses B8 p17 EI9 Autologous peptide epitope B8 Nef WM8 B8 Nef FL8 B8 gp160 YL8 B8 gp160 RL12 B51 RT VL9 B51 p24 NL10 B51 gp160 LI9 A6801 RT AK9 A1, B8 Nef VT15 0 200 400 600 800 1000 SFU / Million PBMC
Results cont. • The transition from LTNP to progressive disease was associated with CTL escape and targeted depletion of HIV-1-specific CD4+ T cells.
Results Cont. • A dramatic loss in T cell recognition was seen to the emerging env gp160 YL8 and Nef AL9 epitope variant. • A concomitant loss of recognition was seen towards the p24 KY15 CD4+ T cell epitope despite the absence of sequence variation over time in this epitope.
gp160 YL8 CD8+ T cell epitope 1000 gP160 B8 YL8 epitope 04/1998 QARVLAVERY LKDQQLLGLW GCSGKLICTT 09/1999 .......... .......... .......... 09/2001 .......... .R........ .......... 06/2002 .......... .R........ .......... 12/2002 .......... .R........ .......... 06/2003 .......... .R........ .......... 07/2004 .......... .R........ .......... 800 600 SFU / Million PBMC 400 200 NT 0 YLKDQQLL 1999 2002 2004 YLRDQQLL Sample year
Nef AL9 CD8+ T cell epitope 1000 Nef: B51 AL9 180 190 200 08/1992 MEDPEKEVLV WKFDSRLAFH HMARELHPEY 03/1993 .......... .......... .......... 10/1993 .......... .......... .......... 04/1998 .........M .......... .......... 06/2002 .......... .........R ......... 12/2002 .......... .........R .......... 06/2003 .......... .........R .......... 07/2004 .......... .........R .......... 800 600 SFU/Million PBMC 400 200 0 2004 Sample year WKFDSRLAFHHMARELHPEY WKFDSRLAFRHMARELHPEY
gag KY15 CD4+ T cell epitope. gag: DR KY15 270 280 290 08/1992 IYKRWIILGL NKIVRMYSPT SILDIRQGPK 03/1993 .......... .......... .......... 10/1993 .......... .......... .......... 04/1998 .......... .......... .......... 12/2002 .......... .......... .......... 06/2003 .......... .......... .......... 07/2004 .......... .......... ..........
CONCLUSIONS In this patient the LTNP phase was associated with: • A broadly directed T cell immune response. • The presence of elongated V2 domain. • Consistent usage of coreceptor CCR5 throughout the course of infection.
Conclusions cont. The transition from LTNP to progressive disease was associated with: • The acquisition of viral mutations conferring CTL escape. • Targeted depletion of HIV-1-specific CD4+ Tcells.
Conclusions cont. • These data help to identify the correlates of protection from disease progression.
We thank the patient for his long-term participation in the study.