How to find a therapeutic TCR

Consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

Functional screening for the high-throughput identification of therapeutic TCRs

In an ideal world, a perfect TCR with therapeutic value should be tumor-specific, highly functional and recognizing a shared target, so that the same TCR could be used to treat a broad range of patients and tumor types. As discussed below, the identification of new promising tumor-specific antigens and the development of TCR functional screenings have been helping to fulfill the first two requirements. Unfortunately, the idea of establishing “off-the-shelf” TCR libraries to treat patients who share the same tumor antigen has become less realistic.

The complexity of TCR target recognition already poses a limitation to the sharing of the same therapeutic TCR. T cells recognize target proteins in the form of short peptides (epitopes) presented by the major histocompatibility complex (MHC) [26(link is external)], where the epitope is allocated in the MHC binding grove due to interactions between conserved anchor residues of the peptide and amino acids of the MHC. Only some peptides generate a stable pMHCs that are transported to the cell membrane for epitope presentation. MHCs (also named “human leucocyte antigens,” HLAs) are highly polymorphic; thus, each epitope has a different stability for the different HLAs and some epitope-HLA combinations simply do not occur. In addition, only a few HLA alleles are expressed by an individual (only 6 out of hundred variants). This means that i) the same antigen can elicit immune responses through different epitopes according to the HLA context and ii) HLA haplotypes shape the array of presented epitopes of an individual. In conclusion, HLA-restriction of TCR target recognition limits the number of patients who could benefit from the same TCR-based therapy.

D'Ippolito, E. et al. Needle in a Haystack: The Naive Repertoire as a Source of T Cell Receptors for AdoptiveTherapy with Engineered T Cells.

Personnel

Dr.

Elvira D'Ippolito

Head of Translational Cell Therapy Unit

Phone.: 089-4140-6870

eMail: elvira.dippolito@tum.de(link sends e-mail)

Multiplexed identification of TCRs against several epitopes

Sublethal infection of mice with the Gram-positive bacterium Listeria monocytogenes results in the development of very effective and long-lasting protective immunity, mediated primarily by CD8+ and CD4+ Listeria-specific T cells. Using MHC multimer reagents, we want to characterize the determinants of effective protective immunity in this experimental model: how, when and where are Listeria-specific memory T cell populations generated in vivo? What is the contribution of different Listeria-specific subpopulations (defined by their lineage, epitope-specificity, phenotype, functional status) to protective immunity? Is there functional interaction/synergism between different Listeria-specific T cell subpopulations which is important for the quality of protective immunity? Different experimental strategies are used to address these questions (e.g. gene knockout mice, transgenic mice, ENU mutagenesis). These studies are designed to shed light on the basic requirements for effective protective immunity; a better understanding of immunological memory will facilitate the development of new, more effective vaccine strategies. An additional clinical application of MHC tetramers is the diagnostic monitoring of antigen-specific T cell immunity.

Understanding the immunology of NTDs in Benin

Personnel

Sebastian Scheu

MD Student

Tel.: 089-4140-6244

eMail: sebastian.scheu@tum.de(link sends e-mail)

Novel and rapid strategies for TCR characterization

MHC multimer technology allows both identification and isolation of epitope-specific T cells. Especially with the help of the recently developed reversible MHC-multimer staining (Streptamers) it may be possible to purify and adoptively transfer epitope-specific T cell populations into recipients, a technique that would have broad clinical applications. We are pursuing the development of methods to efficiently purify tetramer-positive T cells and prepare them for adoptive transfer. Adoptive transfer of epitope-specific T cells will initially be tested in the murine Listeriosis model in order to address some basic experimental questions: Is it possible to transfer pathogen-specific protective immunity into naïve individuals by adoptive transfer of purified tetramer-positive, epitope-specific T cells? What are the minimal requirements (absolute number, epitope specificity, lineage, functional status) for effective adoptive transfer of protective immunity? Similar studies will be performed in other experimental models (e.g. chronic infections).