Efforts are being made worldwide to understand the immune response to SARS-CoV-2, the virus responsible for the COVID-19 pandemic, including the impact of T cell immunity and cross-recognition with seasonal coronaviruses. Screening SARS-CoV-2 peptide pools revealed that the nucleocapsid (N) protein induced an immunodominant response in HLA-B7 + COVID-19-recovered individuals that was also detectable in unexposed donors. A single N-encoded epitope that was highly conserved across circulating coronaviruses drove this immunodominant response. In vitro peptide stimulation and crystal structure analyses revealed T cell-mediated cross-reactivity towards circulating OC43 and HKU-1 beta coronaviruses, but not 229E or NL63 alpha coronaviruses, due to different peptide conformations. TCR sequencing indicated cross-reactivity was driven by private T cell receptor repertoires with a bias for TRBV27 and a long CDR3β loop. Together, our findings demonstrate the basis of selective T cell cross-reactivity towards an immunodominant SARS-CoV-2 epitope and its homologues from seasonal coronaviruses, suggesting long-lived protective immunity.

Role of the funding source:The funders of the study had no role in the study design, data collection, data analysis, data interpretation, or the writing of the manuscript. The corresponding authors had full access to all the data in the study and had final responsibility for the decision to submit for publication. Conflict of interest: MPP has received consulting fees and research funding from Atara Biotherapeutics and is a member of the Neurology Clinical Advisory Panel of Atara Biotherapeutics. CS has received consulting fees from Atara Biotherapeutics. SB is a member of the advisory boards of Roche, Sanofi Genzyme, Merck, and Teva. KAG has received personal fees from Roche and travel support from Sanofi Aventis. AS has received educational and travel support from Merck Serono Australia. KDH is a member of the advisory boards of Merck Serono Australia, Biogen Australia, and Roche Australia. BTA is an employee of, and owns equity shares in, Atara Biotherapeutics. SRB has received a license fee payment from Atara Biotherapeutics. AC has received a consulting fee from Sanofi Genzyme. RK is a consultant and member of the scientific advisory board of Atara Biotherapeutics and has received a license fee payment and research funding from Atara Biotherapeutics.

Purpose: Candidate circulating disease response biomarkers for classical Hodgkin lymphoma (cHL) might arise from Hodgkin-Reed-Sternberg (HRS) cells or nonmalignant tumor-infiltrating cells. HRS cells are sparse within the diseased node, whereas benign CD163 þ M2 tissue-associated macrophages (TAM) are prominent. CD163 þ cells within the malignant node may be prognostic, but there is no data on serum CD163 (sCD163). The HRS-specific serum protein sTARC shows promise as a disease response biomarker. Tumor-specific and tumor-infiltrating circulating biomarkers have not been compared previously. Experimental Design: We prospectively measured sCD163 and sTARC in 221 samples from 47 patients with Hodgkin lymphoma and 21 healthy participants. Blood was taken at five fixed time-points prior, during, and after first-line therapy. Results were compared with radiological assessment and plasma Epstein-Barr virus DNA (EBV-DNA). Potential sources of circulating CD163 were investigated, along with immunosuppressive properties of CD163.Results: Pretherapy, both sCD163 and sTARC were markedly elevated compared with healthy and complete remission samples. sCD163 better reflected tumor burden during therapy, whereas sTARC had greater value upon completion of therapy. sCD163 correlated with plasma EBV-DNA, and associated with B symptoms, stage, and lymphopenia. Circulating CD163 þ monocytes were elevated in patients, indicating that sCD163 are likely derived from circulating and intratumoral cells. Depletion of cHL CD163 þ monocytes markedly enhanced T-cell proliferation, implicating monocytes and/or TAMs as potential novel targets for immunotherapeutic manipulation. Conclusion:The combination of circulating tumor-infiltrate (sCD163) and tumor-specific (sTARC) proteins is more informative than either marker alone as disease response biomarkers in early and advanced disease during first-line therapy for cHL.

Leukaemia Foundation of Queensland, Kasey-Anne Oklobdzijato Memorial Fund, the Australasian Leukaemia and Lymphoma Group (Malcolm Broomhead Bequest), the Australian Cancer Research Foundation, and the Cancer Council of Queensland.

Purpose: To investigate the relationship between the intratumoral T-cell receptor (TCR) repertoire and the tumor microenvironment (TME) in de novo diffuse large B-cell lymphoma (DLBCL) and the impact of TCR on survival.Experimental Design: We performed high-throughput unbiased TCRb sequencing on a population-based cohort of 92 patients with DLBCL treated with conventional (i.e., non-checkpoint blockade) frontline "R-CHOP" therapy. Key immune checkpoint genes within the TME were digitally quantified by nanoString. The primary endpoints were 4-year overall survival (OS) and progression-free survival (PFS).Results: The TCR repertoire within DLBCL nodes was abnormally narrow relative to non-diseased nodal tissues (P < 0.0001). In DLBCL, a highly dominant single T-cell clone was associated with inferior 4-year OS rate of 60.0% [95% confidence interval (CI), 31.7%-79.6%], compared with 79.8% in patients with a low dominant clone (95% CI, 66.7%-88.5%; P ¼ 0.005). A highly dominant clone also predicted inferior 4-year PFS rate of 46.6% (95% CI, 22.5%-76.6%) versus 72.6% (95% CI, 58.8%-82.4%, P ¼ 0.008) for a low dominant clone. In keeping, clonal expansions were most pronounced in the EBV þ DLBCL subtype that is known to express immunogenic viral antigens and is associated with particularly poor outcome. Increased T-cell diversity was associated with significantly elevated PD-1, PD-L1, and PD-L2 immune checkpoint molecules. Conclusions: Put together, these findings suggest that the TCR repertoire is a key determinant of the TME. Highly dominant T-cell clonal expansions within the TME are associated with poor outcome in DLBCL treated with conventional frontline therapy.

The data presented here demonstrate for the first time the clinical safety of CMV-specific adoptive T-cell therapy and its potential therapeutic benefit for SOT patients with recurrent and/or drug-resistant CMV infection or disease.

Primary central nervous system (pCNS) posttransplant lymphoproliferative disorder (PTLD) is a complication of solid organ transplantation characterized by poor outcome. In contrast to systemic PTLD, Epstein-Barr virus (EBV)-association of pCNS PTLD is almost universal, yet viral and cellular data are limited. To identify differences in the pattern of EBV-association of pCNS and systemic PTLD, we analyzed the expression of latent and lytic EBV transcripts and the viral and cellular microRNAome in nine pCNS (eight EBV-associated) and in 16 systemic PTLD samples (eight EBV-associated). Notably although 15/16 EBV-associated samples exhibited a viral type III latency pattern, lytic transcripts were also strongly expressed. Members of the ebv-miR-BHRF1 and ebv-miR-BART clusters were expressed in virtually all EBV-associated PTLD samples. There were 28 cellular microRNAs differentially expressed between systemic and pCNS PTLD. pCNS PTLD expressed lower hsa-miR-199a-5p/3p and hsa-miR-143/145 (implicated in nuclear factor kappa beta and c-myc signaling) as compared to systemic PTLD. Unsupervised nonhierarchical clustering of the viral and cellular microRNAome distinguished non-EBV-associated from EBV-associated samples and identified a separate group of EBV-associated pCNS PTLD that displayed reduced levels of B cell lymphoma associated oncomiRs such as hsa-miR-155, -21, -221 and the hsa-miR-17-92 cluster. EBV has a major impact on viral and cellular microRNA expression in EBV-associated pCNS PTLD.

Cellular immunotherapeutics targeting the human papillomavirus (HPV)–16 E6 and E7 proteins have achieved limited success in HPV-positive oropharyngeal cancer (OPC). Here we have conducted proteome-wide profiling of HPV-16–specific T cell responses in a cohort of 66 patients with HPV-associated OPC and 22 healthy individuals. Unexpectedly, HPV-specific T cell responses from OPC patients were not constrained to the E6 and E7 antigens; they also recognized E1, E2, E4, E5, and L1 proteins as dominant targets for virus-specific CD8+ and CD4+ T cells. Multivariate analysis incorporating tumor staging, treatment status, and smoking history revealed that treatment status had the most significant impact on HPV-specific CD8+ and CD4+ T cell immunity. Specifically, the breadth and overall strength of HPV-specific T cell responses were significantly higher before the commencement of curative therapy than after therapy. These data provide the first glimpse of the overall human T cell response to HPV in a clinical setting and offer groundbreaking insight into future development of cellular immunotherapies for HPV-associated OPC patients.