Characterizing the human T-cell receptor repertoire by massively parallel sequencing.
This is a comparative approach to understanding the individual variation in the human T-cell repertoires at the sequence level.
|Project Leaders||Robert Holt|
|Project Co-Investigators||John Webb, Angela Brooks-Wilson , Brad Nelson|
T-cells circulating in blood are the key players in a person's adaptive immune system and are particularly important in recognizing and killing other cells that are infected with viruses, or that carry cancer causing mutations. Because there are a vast number of different infectious agents or cancer causing mutations possible, a vast number of T-cell variants are required to recognize them. The component of the T-cell responsible for this recognition is the T-cell receptor, and the variation required for recognition is generated mainly by shuffling the large number of short DNA segments that comprise T-cell receptor genes. Although the central importance and T-cell receptor in adaptive immunity is well established, the actual number and diversity of T-cells that exist in an individual (known as the T-cell "repertoire"), how this changes in response to immune challenge, and how it varies from one individual to the next, remains unknown. We have used the latest DNA sequencing technologies to develop an approach for examining the T-cell repertoire in a given blood sample by directly sequencing T-cell receptor genes. In the study proposed here we will work on improving the performance of this method and we will use it to determine the number of different T-cell receptors in a typical blood sample, how this varies from person to person, how it changes with age, and how it is affected by long term viral infections. The results of this study will improve our understanding of adaptive immunity and will facilitate the future development of immunoassays for diagnostic testing and immune intervention in cancer, infectious disease and auto-immunity and transplantation medicine.
- Deep sequencing of a “reference” T-cell repertoire from a single individual.
- Sequence naïve and responder compartments of the peripheral T-cell repertoire in healthy adults (from young to elderly) and explore how the relative size and diversity of these compartments varies between individuals and age groups.
- Determine how historical exposure to latent persistent viruses influences immune repertoires and we will characterize T-cells responsive to common viral antigens.
- We will also adapt our immunoprofiling approach to analysis of B-cell/Immunoglobulin repertoires.
This study will advance our knowledge of the human T-cell repertoire and provide the first sequence profiles of B-cell repertoires. We expect to obtain, for the first time, a direct measure of T-cell repertoire size, and also the first glimpse of the extent of individual repertoire variation in health, with age, and in the context of chronic infection. The methods we establish will be applicable to characterizing the response to all sorts of immune challenges, such as acute and latent infections, vaccination, organ transplantation, graft vs. host disease, immunosuppression and auto-immunity.