The entire DNA sequence of chromosome III of the yeast Saccharomyces cerevisiae has been determined. This is the first complete sequence analysis of an entire chromosome from any organism. The 315-kilobase sequence reveals 182 open reading frames for proteins longer than 100 amino acids, of which 37 correspond to known genes and 29 more show some similarity to sequences in databases. Of 55 new open reading frames analysed by gene disruption, three are essential genes; of 42 non-essential genes that were tested, 14 show some discernible effect on phenotype and the remaining 28 have no overt function.

Checkpoint blockade can reverse T-cell exhaustion and promote antitumor responses. Although blocking the PD-1 pathway has been successful in Hodgkin lymphoma, response rates have been modest in B-cell non-Hodgkin lymphoma (NHL). Coblockade of checkpoint receptors may therefore be necessary to optimize antitumor T-cell responses. Here, characterization of coinhibitory receptor expression in intratumoral T cells from different NHL types identified TIGIT and PD-1 as frequently expressed coinhibitory receptors. Tumors from NHL patients were enriched in CD8+ and CD4+ T effector memory cells that displayed high coexpression of TIGIT and PD-1, and coexpression of these checkpoint receptors identified T cells with reduced production of IFNγ, TNFα, and IL2. The suppressed cytokine production could be improved upon in vitro culture in the absence of ligands. Whereas PD-L1 was expressed by macrophages, the TIGIT ligands CD155 and CD112 were expressed by lymphoma cells in 39% and 50% of DLBCL cases and in some mantle cell lymphoma cases, as well as by endothelium and follicular dendritic cells in all NHLs investigated. Collectively, our results show that TIGIT and PD-1 mark dysfunctional T cells and suggest that TIGIT and PD-1 coblockade should be further explored to elicit potent antitumor responses in patients with NHL.

T cells infiltrating follicular lymphoma (FL) tumors are considered dysfunctional, yet the optimal target for immune checkpoint blockade is unknown. Characterizing coinhibitory receptor expression patterns and signaling responses in FL T-cell subsets might reveal new therapeutic targets. Surface expression of 9 coinhibitory receptors governing T-cell function was characterized in T-cell subsets from FL lymph node tumors and from healthy donor tonsils and peripheral blood samples, using high-dimensional flow cytometry. The results were integrated with T-cell receptor (TCR)-induced signaling and cytokine production. Expression of T-cell immunoglobulin and ITIM domain (TIGIT) ligands was detected by immunohistochemistry. TIGIT was a frequently expressed coinhibitory receptor in FL, expressed by the majority of CD8 T effector memory cells, which commonly coexpressed exhaustion markers such as PD-1 and CD244. CD8 FL T cells demonstrated highly reduced TCR-induced phosphorylation (p) of ERK and reduced production of IFNγ, while TCR proximal signaling (p-CD3ζ, p-SLP76) was not affected. The TIGIT ligands CD112 and CD155 were expressed by follicular dendritic cells in the tumor microenvironment. Dysfunctional TCR signaling correlated with TIGIT expression in FL CD8 T cells and could be fully restored upon culture. The costimulatory receptor CD226 was downregulated in TIGIT compared with TIGIT CD8 FL T cells, further skewing the balance toward immunosuppression. TIGIT blockade is a relevant strategy for improved immunotherapy in FL. A deeper understanding of the interplay between coinhibitory receptors and key T-cell signaling events can further assist in engineering immunotherapeutic regimens to improve clinical outcomes of cancer patients. .