Tracking TCRβ Sequence Clonotype Expansions during Antiviral Therapy Using High-Throughput Sequencing of the Hypervariable Region.
To maintain a persistent infection viruses such as hepatitis C virus (HCV) employ a range of mechanisms that subvert protective T cell responses. The suppression of antigen-specific T cell responses by HCV hinders efforts to profile T cell responses during chronic infection and antiviral therapy. Conventional methods of detecting antigen-specific T cells utilize either antigen stimulation (e.g., ELISpot, proliferation assays, cytokine production) or antigen-loaded tetramer staining. This limits the ability to profile T cell responses during chronic infection due to suppressed effector function and the requirement for prior knowledge of antigenic viral peptide sequences. Recently, high-throughput sequencing (HTS) technologies have been developed for the analysis of T cell repertoires. In the present study, we have assessed the feasibility of HTS of the TCRβ complementarity determining region (CDR)3 to track T cell expansions in an antigen-independent manner. Using sequential blood samples from HCV-infected individuals undergoing antiviral therapy, we were able to measure the population frequencies of >35,000 TCRβ sequence clonotypes in each individual over the course of 12 weeks. TRBV/TRBJ gene segment usage varied markedly between individuals but remained relatively constant within individuals across the course of therapy. Despite this stable TRBV/TRBJ gene segment usage, a number of TCRβ sequence clonotypes showed dramatic changes in read frequency. These changes could not be linked to therapy outcomes in the present study; however, the TCRβ CDR3 sequences with the largest fold changes did include sequences with identical TRBV/TRBJ gene segment usage and high junction region homology to previously published CDR3 sequences from HCV-specific T cells targeting the HLA-B*0801-restricted (1395)HSKKKCDEL(1403) and HLA-A*0101-restricted (1435)ATDALMTGY(1443) epitopes. The pipeline developed in this proof of concept study provides a platform for the design of future experiments to accurately address the question of whether T cell responses contribute to SVR upon antiviral therapy. This pipeline represents a novel technique to analyze T cell dynamics in situations where conventional antigen-dependent methods are limited due to suppression of T cell functions and highly diverse antigenic sequences.
MRC - University of Glasgow Centre for Virus Research, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK; School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland.
Mark W
MW
Robinson
MRC - University of Glasgow Centre for Virus Research, Institute of Infection, Immunity and Inflammation, University of Glasgow , Glasgow , UK.
Joseph
J
Hughes
MRC - University of Glasgow Centre for Virus Research, Institute of Infection, Immunity and Inflammation, University of Glasgow , Glasgow , UK.
Gavin S
GS
Wilkie
MRC - University of Glasgow Centre for Virus Research, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK; Gartnavel General Hospital, NHS Greater Glasgow and Clyde, Glasgow, UK.
Rachael
R
Swann
Glasgow Royal Infirmary, NHS Greater Glasgow and Clyde , Glasgow , UK.
Stephen T
ST
Barclay
Gartnavel General Hospital, NHS Greater Glasgow and Clyde , Glasgow , UK.
Peter R
PR
Mills
MRC - University of Glasgow Centre for Virus Research, Institute of Infection, Immunity and Inflammation, University of Glasgow , Glasgow , UK.
Arvind H
AH
Patel
MRC - University of Glasgow Centre for Virus Research, Institute of Infection, Immunity and Inflammation, University of Glasgow , Glasgow , UK.
Emma C
EC
Thomson
MRC - University of Glasgow Centre for Virus Research, Institute of Infection, Immunity and Inflammation, University of Glasgow , Glasgow , UK.
John
J
McLauchlan
T cell receptor; TBRJ; TRBV; clonotype expansion; complementarity determining region 3; hepatitis C virus; high-throughput sequencing