Genome-wide CRISPR screens identify CD48 defining susceptibility to NK cytotoxicity in peripheral T-cell lymphomas.

Adult T-cell leukemia/lymphoma (ATLL) is one of the aggressive peripheral T-cell neoplasms with a poor prognosis. Accumulating evidence demonstrates that escape from adaptive immunity is a hallmark of ATLL pathogenesis. However, the mechanisms by which ATLL cells evade natural killer (NK)-cell-mediated immunity have been poorly understood. Here we show that CD48 expression in ATLL cells determines the sensitivity for NK-cell-mediated cytotoxicity against ATLL cells. We performed unbiased genome-wide clustered regularly interspaced short palindromic repeat (CRISPR) screening using 2 ATLL-derived cell lines and discovered CD48 as one of the best-enriched genes whose knockout conferred resistance to YT1-NK cell line-mediated cytotoxicity. The ability of CD48-knockout ATLL cells to evade NK-cell effector function was confirmed using human primary NK cells with reduced interferon-γ (IFNγ) induction and degranulation. We found that primary ATLL cells had reduced CD48 expression along with disease progression. Furthermore, other subgroups among aggressive peripheral T-cell lymphomas (PTCLs) also expressed lower concentrations of CD48 than normal T cells, suggesting that CD48 is a key molecule in malignant T-cell evasion of NK-cell surveillance. Thus, this study demonstrates that CD48 expression is likely critical for malignant T-cell lymphoma cell regulation of NK-cell-mediated immunity and provides a rationale for future evaluation of CD48 as a molecular biomarker in NK-cell-associated immunotherapies.

Early vaccine-mediated strain-specific cytokine imbalance induces mild immunopathology during influenza infection.

Influenza A viruses (IAVs) exist as distinct serological subtypes, with limited antibody cross reactivity compared with T-cell responses, leading to universal vaccines that elicit robust T-cell responses entering clinical trials to combat pandemic and zoonotic outbreaks. Previously we have extensively characterized the viral-vectored universal vaccine, Wyeth/IL-15/5flu, a group 1 hemagglutinin, H5N1-based vaccine using a vaccinia backbone with interleukin (IL)-15. The vaccine elicits robust T-cell responses to provide heterosubtypic protection from lethal infection; however, we have also observed short-term morbidity of vaccinated mice with a disparity between the effects of sublethal infection with group 1 and 2 IAV strains. At day 3 of H3N2 (group 2 IAV) infection, there was a heavily skewed T helper type 1 response in vaccinated infected mice with overproduction of cytokines and reduced chemokines, whereas H1N1 (group 1 IAV) infection had increased innate cellular responses. These findings suggest that increased and early immune activation by T-cell activating vaccines may induce mild immunopathology when there is a mismatch between non-neutralizing antibody and cross-reactive memory T-cell responses leading to exuberant cytokine production. Therefore, to avoid overstimulating proinflammatory immune responses upon infection, universal influenza vaccines that elicit strong T-cell immunity will need a robust cross-reactive antibody response.

Deregulation of miRNAs-cMYC circuits is a key event in refractory celiac disease type-2 lymphomagenesis.

A percentage of celiac disease (CD) patients develop refractory type-2 disease (RCD2), a condition associated with increased risk of enteropathy-associated T-cell-lymphoma (EATL) and without therapeutic option. Therefore, we profiled the miRNome in series of peripheral T-cell lymphomas (PTCLs), CD, RCD1 or 2 and in the murine interleukin-15 (IL15)-transgenic (TG) model of RCD. The transcriptome was analyzed in 18 intestinal T-cell lymphomas (ITLs). Bioinformatics pipelines provided significant microRNA (miRNA) lists and predicted targets that were confirmed in a second set of patients. Our data show that ITLs have a unique miRNA profile with respect to other PTCLs. The c-MYC regulated miR-17/92 cluster distinguishes monomorphic epitheliotropic ITL (MEITL) from EATL and prognosticates EATL outcome. These miRNAs are decreased in IL15-TG mice upon Janus kinase (JAK) inhibition. The random forest algorithm identified a signature of 38 classifier miRNAs, among which, the miR-200 and miR-192/215 families were progressively lost in RCD2 and ITL-CD, whereas miR-17/92 and C19MC miRNAs were up-regulated. Accordingly, SMAD3, MDM2, c-Myc and activated-STAT3 were increased in RCD2 and EATL tissues while JAK inhibition in IL15-TG mice restored their levels to baseline. Our data suggest that miRNAs circuit supports activation of STAT3 and c-Myc oncogenic signaling in RCD2, thus contributing to lymphomagenesis. This novel understanding might pave the way to personalized medicine approaches for RCD and EATL.

Chimeric antigen receptor modified T cells that target chemokine receptor CCR4 as a therapeutic modality for T-cell malignancies.

With the emerging success of treating CD19 expressing B cell malignancies with ex vivo modified, autologous T cells that express CD19-directed chimeric antigen receptors (CAR), there is intense interest in expanding this evolving technology to develop effective modalities to treat other malignancies including solid tumors. Exploiting this approach to develop a therapeutic modality for T cell malignancies for which the available regimens are neither curative, nor confer long term survival we generated a lentivirus-based CAR gene transfer system to target the chemokine receptor CCR4 that is over-expressed in a spectrum of T cell malignancies as well as in CD4+ CD25+ Foxp3+ T regulatory cells that accumulate in the tumor microenvironment constituting a barrier against anti-tumor immunity. Ex vivo modified, donor-derived T cells that expressed CCR4 directed CAR displayed antigen-dependent potent cytotoxicity against patient-derived cell lines representing ATL, CTCL, ALCL and a subset of HDL. Furthermore, these CAR T cells also eradicated leukemia in a mouse xenograft model of ATL illustrating the potential utility of this modality in the treatment of a wide spectrum of T cell malignancies.

IL-15 adjuvanted multivalent vaccinia-based universal influenza vaccine requires CD4+ T cells for heterosubtypic protection.

Current influenza vaccines are ineffective against novel viruses and the source or the strain of the next outbreak of influenza is unpredictable; therefore, establishing universal immunity by vaccination to limit the impact of influenza remains a high priority. To meet this challenge, a novel vaccine has been developed using the immunogenic live vaccinia virus as a vaccine vector, expressing multiple H5N1 viral proteins (HA, NA, M1, M2, and NP) together with IL-15 as a molecular adjuvant. Previously, this vaccine demonstrated robust sterile cross-clade protection in mice against H5 influenza viruses, and herein its use has been extended to mediate heterosubtypic immunity toward viruses from both group 1 and 2 HA lineages. The vaccine protected mice against lethal challenge by increasing survival and significantly reducing lung viral loads against the most recent human H7N9, seasonal H3N2, pandemic-2009 H1N1, and highly pathogenic H7N7 influenza A viruses. Influenza-specific antibodies elicited by the vaccine failed to neutralize heterologous viruses and were unable to confer protection by passive transfer. Importantly, heterologous influenza-specific CD4(+) and CD8(+) T-cell responses that were elicited by the vaccine were effectively recalled and amplified following viral challenge in the lungs and periphery. Selective depletion of T-cell subsets in the immunized mice revealed an important role for CD4(+) T cells in heterosubtypic protection, despite low sequence conservation among known MHC-II restricted epitopes across different influenza viruses. This study illustrates the potential utility of our multivalent Wyeth/IL-15/5Flu as a universal influenza vaccine with a correlate of protective immunity that is independent of neutralizing antibodies.

Janus Kinase Inhibitor Tofacitinib Shows Potent Efficacy in a Mouse Model of Autoimmune Lymphoproliferative Syndrome (ALPS).

PURPOSE: Autoimmune lymphoproliferative syndrome (ALPS) is a non-malignant genetic disorder of lymphocyte homeostasis with defective Fas-mediated apoptosis. Current therapies for ALPS primarily target autoimmune manifestations with non-specific immune suppressants with variable success thus highlighting the need for better therapeutics for this disorder. METHODS: The spectrum of clinical manifestations of ALPS is mirrored by MRL/lpr mice that carry a loss of function mutation in the Fas gene and have proven to be a valuable model in predicting the efficacy of several therapeutics that are front-line modalities for the treatment of ALPS. We evaluated the potential efficacy of tofacitinib, an orally active, pan-JAK inhibitor currently approved for rheumatoid arthritis as a single agent modality against ALPS using MRL/lpr mice. RESULTS: We demonstrate that a 42-day course of tofacitinib therapy leads to a lasting reversal of lymphadenopathy and autoimmune manifestations in the treated MRL/lpr mice, Specifically, in treated mice the peripheral blood white blood cell counts were reversed to near normal levels with almost a 50 % reduction in the TCRαß(+)CD4(-)CD8(-)T lymphocyte numbers that coincided with a parallel increase in CD8(+) T cells without a demonstrable effect on CD4(+) lymphocytes including FoxP3(+) regulatory T cells. The elevated plasma IgG and IgA levels were also drastically lowered along with a significant reduction in plasmablasts and plasmacytes in the spleen. CONCLUSION: On the basis of these results, it is likely that tofacitinib would prove to be a potent single agent therapeutic modality capable of ameliorating both offending lymphadenopathy as well as autoimmunity in ALPS patients.

Tofacitinib, a janus kinase inhibitor demonstrates efficacy in an IL-15 transgenic mouse model that recapitulates pathologic manifestations of celiac disease.

Celiac disease (CD) is an immune-mediated, inflammatory disorder of the small intestines with a defined genetic etiological component associated with the expression of HLA-DQ2 and/or HLA-DQ8 haplotypes. The dietary consumption of gluten-rich cereals triggers a gluten-specific immune response in genetically susceptible individuals leading to a spectrum of clinical manifestations ranging from an inapparent subclinical disease, to overt enteropathy that can in some individuals progress to enteropathy-associated T cell lymphoma (EATL). The tissue-destructive pathologic process of CD is driven by activated NK-like intraepithelial CD8(+) lymphocytes and the proinflammatory cytokine IL-15 has emerged to be pivotal in orchestrating this perpetual tissue destruction and inflammation. Moreover, transgenic mice that over-express human IL-15 from an enterocyte-specific promoter (T3(b)-hIL-15 Tg) recapitulate many of the disease-defining T and B cell-mediated pathologic features of CD, further supporting the evolving consensus that IL-15 represents a valuable target in devising therapeutic interventions against the form of the disease that is especially refractory to gluten-free diet. In the present study, we evaluated the potential efficacy of tofacitinib, a pan-JAK inhibitor that abrogates IL-15 signaling, as a therapeutic modality against CD using T3(b)-hIL-15 Tg mice. We demonstrate that tofacitinib therapy leads to a lasting reversal of pathologic manifestations in the treated mice, thereby highlighting the potential value of tofacitininb as a therapeutic modality against refractory CD for which no effective therapy exists currently. Additionally, the visceral adiposity observed in the tofacitinib-treated mice underscores the importance of continued evaluation of the drug's impact on the lipid metabolism.

Safety (toxicity), pharmacokinetics, immunogenicity, and impact on elements of the normal immune system of recombinant human IL-15 in rhesus macaques.

IL-15 uses the heterotrimeric receptor IL-2/IL-15Rß and the γ chain shared with IL-2 and the cytokine-specific IL-15Rα. Although IL-15 shares actions with IL-2 that include activation of natural killer (NK) and CD8 T cells, IL-15 is not associated with capillary leak syndrome, activation-induced cell death, or with a major effect on the number of functional regulatory T cells. To prepare for human trials to determine whether IL-15 is superior to IL-2 in cancer therapy, recombinant human IL-15 (rhIL-15) was produced under current good manufacturing practices. A safety study in rhesus macaques was performed in 4 groups of 6 animals each that received vehicle diluent control or rhIL-15 at 10, 20, or 50 µg/kg/d IV for 12 days. The major toxicity was grade 3/4 transient neutropenia. Bone marrow examinations demonstrated increased marrow cellularity, including cells of the neutrophil series. Furthermore, neutrophils were observed in sinusoids of enlarged livers and spleens, suggesting that IL-15 mediated neutrophil redistribution from the circulation to tissues. The observation that IL-15 administration was associated with increased numbers of circulating NK and CD8 central and effector-memory T cells, in conjunction with efficacy studies in murine tumor models, supports the use of multiple daily infusions of rhIL-15 in patients with metastatic malignancies.

Development of a highly efficacious vaccinia-based dual vaccine against smallpox and anthrax, two important bioterror entities.

Bioterrorism poses a daunting challenge to global security and public health in the 21st century. Variola major virus, the etiological agent of smallpox, and Bacillus anthracis, the bacterial pathogen responsible for anthrax, remain at the apex of potential pathogens that could be used in a bioterror attack to inflict mass casualties. Although licensed vaccines are available for both smallpox and anthrax, because of inadequacies associated with each of these vaccines, serious concerns remain as to the deployability of these vaccines, especially in the aftermath of a bioterror attack involving these pathogens. We have developed a single vaccine (Wyeth/IL-15/PA) using the licensed Wyeth smallpox vaccine strain that is efficacious against both smallpox and anthrax due to the integration of immune-enhancing cytokine IL-15 and the protective antigen (PA) of B. anthracis into the Wyeth vaccinia virus. Integration of IL-15 renders Wyeth vaccinia avirulent in immunodeficient mice and enhances anti-vaccinia immune responses. Wyeth/IL-15/PA conferred sterile protection against a lethal challenge of B. anthracis Ames strain spores in rabbits. A single dose of Wyeth/IL-15/PA protected 33% of the vaccinated A/J mice against a lethal spore challenge 72 h later whereas a single dose of licensed anthrax vaccine protected only 10%. Our dual vaccine Wyeth/IL-15/PA remedies the inadequacies associated with the licensed vaccines, and the inherent ability of Wyeth vaccinia virus to be lyophilized without loss of potency makes it cold-chain independent, thus simplifying the logistics of storage, stockpiling, and field delivery in the event of a bioterror attack involving smallpox or anthrax.

Transient and persistent effects of IL-15 on lymphocyte homeostasis in nonhuman primates.

Interleukin-15 (IL-15) is a cytokine with potential therapeutic application in individuals with cancer or immunodeficiency to promote natural killer (NK)- and T-cell activation and proliferation or in vaccination protocols to generate long-lived memory T cells. Here we report that 10-50 µg/kg IL-15 administered intravenously daily for 12 days to rhesus macaques has both short- and long-lasting effects on T-cell homeostasis. Peripheral blood lymphopenia preceded a dramatic expansion of NK cells and memory CD8 T cells in the circulation, particularly a 4-fold expansion of central memory CD8 T cells and a 6-fold expansion of effector memory CD8 T cells. This expansion is a consequence of their activation in multiple tissues. A concomitant inverted CD4/CD8 T-cell ratio was observed throughout the body at day 13, a result of preferential CD8 expansion. Expanded T- and NK-cell populations declined in the blood soon after IL-15 was stopped, suggesting migration to extralymphoid sites. By day 48, homeostasis appears restored throughout the body, with the exception of the maintenance of an inverted CD4/CD8 ratio in lymph nodes. Thus, IL-15 generates a dramatic expansion of short-lived memory CD8 T cells and NK cells in immunocompetent macaques and has long-term effects on the balance of CD4(+) and CD8(+) T cells.

Antibody-mediated blockade of IL-15 reverses the autoimmune intestinal damage in transgenic mice that overexpress IL-15 in enterocytes.

Celiac disease (CD) is an autoimmune inflammatory disease with a relatively high prevalence especially in the western hemisphere. A strong genetic component is involved in the pathogenesis of CD with virtually all individuals that develop the disease carrying HLA-DQ alleles that encode specific HLA-DQ2 or HLA-DQ8 heterodimers. Consumption of cereals rich in gluten triggers a chronic intestinal inflammation in genetically susceptible individuals leading to the development of CD. Emerging evidence has implicated a central role for IL-15 in the orchestration and perpetuation of inflammation and tissue destruction in CD. Therefore, IL-15 represents an attractive target for development of new therapies for CD. Transgenic mice that express human IL-15 specifically in enterocytes (T3(b)-hIL-15 Tg mice) develop villous atrophy and severe duodeno-jejunal inflammation with massive accumulation of NK-like CD8(+) lymphocytes in the affected mucosa. We used these mice to demonstrate that blockade of IL-15 signaling with an antibody (TM-beta1) that binds to murine IL-2/IL-15Rbeta (CD122) leads to a reversal of the autoimmune intestinal damage. The present study, along with work of others, provides the rationale to explore IL-15 blockade as a test of the hypothesis that uncontrolled expression of IL-15 is critical in the pathogenesis and maintenance of refractory CD.

Next-generation T cell-activating vaccination increases influenza virus mutation prevalence.

To determine the potential for viral adaptation to T cell responses, we probed the full influenza virus genome by next-generation sequencing directly ex vivo from infected mice, in the context of an experimental T cell-based vaccine, an H5N1-based viral vectored vaccinia vaccine Wyeth/IL-15/5Flu, versus the current standard-of-care, seasonal inactivated influenza vaccine (IIV) and unvaccinated conditions. Wyeth/IL-15/5Flu vaccination was coincident with increased mutation incidence and frequency across the influenza genome; however, mutations were not enriched within T cell epitope regions, but high allele frequency mutations within conserved hemagglutinin stem regions and PB2 mammalian adaptive mutations arose. Depletion of CD4+ and CD8+ T cell subsets led to reduced frequency of mutants in vaccinated mice; therefore, vaccine-mediated T cell responses were important drivers of virus diversification. Our findings suggest that Wyeth/IL-15/5Flu does not generate T cell escape mutants but increases stochastic events for virus adaptation by stringent bottlenecks.

Transgenic mice that overexpress human IL-15 in enterocytes recapitulate both B and T cell-mediated pathologic manifestations of celiac disease.

Celiac disease (CD) is a chronic immune-mediated intestinal inflammatory disorder afflicting genetically susceptible individuals triggered by the consumption of dietary cereals with high gluten content. As with many other organ-specific autoimmune diseases, the dominant tissue-destructive inflammation in CD is T cell-mediated. The proinflammatory cytokine IL-15 that is overexpressed in the intestinal epithelium of CD patients has emerged as a pivotal element that orchestrates intestinal inflammation and T cell-mediated autoimmune tissue destruction. Although no animal model exists that recapitulates the full spectrum of CD pathophysiology, we have previously reported that transgenic mice that overexpress human IL-15 in enterocytes (T3(b)-hlL-15 Tg) display many of the T cell-mediated pathologic features seen in CD. Extending these observations, we now report that T3(b)-hlL-15 Tg mice in addition to recapitulating T cell-mediated effects also display autoantibodies including those against tissue transglutaminase 2 and extensive lamina propria plasmacytosis, all of which are characteristic of CD, thereby reflecting the possibility that locally expressed IL-15 drives both T and B cell pathologic effects seen in CD. More importantly, these findings support the validity and utility of T3(b)-hlL-15 Tg mice as a reasonable model to investigate not only tissue-destructive pathologic processes in CD, but also to explore novel therapeutic modalities for the treatment of this disease.

Vaccinia virus-based multivalent H5N1 avian influenza vaccines adjuvanted with IL-15 confer sterile cross-clade protection in mice.

The potential for a global influenza pandemic remains significant with epidemiologic and ecologic indicators revealing the entrenchment of the highly pathogenic avian influenza A H5N1 in both wild bird populations and domestic poultry flocks in Asia and in many African and European countries. Indisputably, the single most effective public health intervention in mitigating the devastation such a pandemic could unleash is the availability of a safe and effective vaccine that can be rapidly deployed for pre-exposure vaccination of millions of people. We have developed two vaccinia-based influenza vaccines that are molecularly adjuvanted with the immune stimulatory cytokine IL-15. The pentavalent Wyeth/IL-15/5Flu vaccine expresses the hemagglutinin, neuraminidase, and nucleoprotein derived from the H5N1 influenza virus A/Vietnam/1203/2004 and the matrix proteins M1 and M2 from the H5N1 A/CK/Indonesia/PA/2003 virus on the backbone of a currently licensed smallpox vaccine. The bivalent MVA/IL-15/HA/NA vaccine expresses only the H5 hemagglutinin and N1 neuraminidase on the modified vaccinia virus Ankara (MVA) backbone. Both vaccines induced cross-neutralizing Abs and robust cellular immune responses in vaccinated mice and conferred sterile cross-clade protection when challenged with the H5N1 virus of a different clade. In addition to having potential as a universal influenza vaccine, in the event of an impending pandemic the Wyeth/IL-15/5Flu is also readily amenable to bulk production to cover the global population. For those individuals for whom the use of the Wyeth vaccine is contraindicated, our MVA/IL-15/HA/NA offers a substitute or a prevaccine to be used in a mass vaccination campaign similar to the smallpox eradication campaigns of few decades ago.

IL-15 as a mediator of CD4+ help for CD8+ T cell longevity and avoidance of TRAIL-mediated apoptosis.

CD4+ helper T cells contribute to the induction and maintenance of antigen-specific CD8+ T cells. Their absence results in short-lived antigen-specific CD8+ T cells and defective secondary CD8+ T cell responses because of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis. Here, we show that IL-15 codelivered with vaccines can overcome CD4+ T cell deficiency for promoting longevity of antigen-specific CD8+ T cells and avoidance of TRAIL-mediated apoptosis. In both priming and secondary responses, IL-15 down-regulates proapoptotic Bax, an intermediate in TRAIL-mediated apoptosis, and increases anti-apoptotic Bcl-X(L) in CD8+ T cells. Thus, IL-15 is sufficient to mimic CD4+ T cell help. Antigen-specific CD4+ T cells induce dendritic cells (DCs) to produce IL-15. IL-15 is also necessary for optimal help, because helper cells do not deliver effective help through IL-15-/- DCs. Therefore, IL-15 codelivered with vaccines can overcome CD4+ helper T cell deficiency for induction of functionally efficient CD8+ T cells and maintenance of CD8+ cytotoxic T lymphocytes (CTLs), and IL-15 is probably one of the natural mediators of help. These findings suggest new vaccine strategies against infections and cancers, especially in individuals with CD4-deficiency.

Development of leading first-generation vaccines against SARS-CoV-2.

SARS-CoV-2 has infected more than 167 million individuals globally. Highly effective and safe vaccines are required to accelerate the development of herd immunity to end the pandemic. This review focuses on vaccines that are being developed at unprecedented speed globally and are completing late phase clinical trials to meet this urgent need.

Short-course IL-15 given as a continuous infusion led to a massive expansion of effective NK cells: implications for combination therapy with antitumor antibodies.

BACKGROUND: Full application of cytokines as oncoimmunotherapeutics requires identification of optimal regimens. Our initial effort with intravenous bolus recombinant human interleukin-15 (rhIL-15) was limited by postinfusional reactions. Subcutaneous injection and continuous intravenous infusion for 10 days (CIV-10) provided rhIL-15 with less toxicity with CIV-10 giving the best increases in CD8+ lymphocytes and natural killer (NK) cells. To ease rhIL-15 administration, we shortened time of infusion. Treatment with rhIL-15 at a dose of 3-5 µg/kg as a 5-day continuous intravenous infusion (CIV-5) had no dose-limiting toxicities while effector cell stimulation was comparable to the CIV-10 regimen. METHODS: Eleven patients with metastatic cancers were treated with rhIL-15 CIV-5, 3 µg (n=4), 4 µg (n=3), and 5 µg/kg/day (n=4) in a phase I dose-escalation study (April 6, 2012). RESULTS: Impressive expansions of NK cells were seen at all dose levels (mean 34-fold), including CD56bright NK cells (mean 144-fold for 4 µg/kg), as well as an increase in CD8+ T cells (mean 3.38-fold). At 5 µg/kg/day, there were no dose-limiting toxicities but pulmonary capillary leak and slower patient recovery. This led to our choice of the 4 µg/kg as CIV-5 dose for further testing. Cytolytic capacity of CD56bright and CD56dim NK cells was increased by interleukin-15 assayed by antibody-dependent cellular cytotoxicity (ADCC), natural cytotoxicity and natural killer group 2D-mediated cytotoxicity. The best response was stable disease. CONCLUSIONS: IL-15 administered as CIV-5 substantially expanded NK cells with increased cytotoxic functions. Tumor-targeting monoclonal antibodies dependent on ADCC as their mechanism of action including alemtuzumab, obinutuzumab, avelumab, and mogamulizumab could benefit from those NK cell expansions and provide a promising therapeutic strategy. TRIAL REGISTRATION NUMBERS: NCT01572493, NCT03759184, NCT03905135, NCT04185220 and NCT02689453.

Inclusion of an E7 DNA Amplification Test Improves the Robustness of Human Papillomavirus-Associated Oropharyngeal Squamous Cell Carcinoma Diagnosis.

BACKGROUND: The rise in human papillomavirus (HPV) infection rates over the last few decades in the USA has contributed to a significant increase in the overall incidence of patients diagnosed with squamous cell carcinoma of the head and neck. These head and neck carcinomas develop in the oropharynx, with more than 90% of them caused by infection with high-risk HPV type 16. Patients diagnosed with HPV-induced oropharyngeal squamous cell carcinomas (OPSCCs) have a better prognosis and treatment response than those diagnosed with head and neck cancers caused by alcohol consumption and tobacco use. To identify patients with HPV-positive OPSCC, new guidelines recommend positive staining of oropharyngeal tissues for p16 INK4a (p16) by immunohistochemistry (IHC). Herein we discuss the testing algorithm that was adopted to address discrepant results between p16 IHC and a DNA in situ hybridization (ISH) test used routinely to diagnose HPV-positive OPSCC patients. METHODS: A DNA polymerase chain reaction (PCR) test that amplifies HPV16 and HPV18 E7 was developed to aid in the diagnosis of HPV-positive OPSCC in a subset of patients. Specimens from these patients stained positive for p16 by an IHC test, but negative for high-risk HPV by a commercial DNA ISH test. Moreover, these results did not match the histopathological characteristics of the specimens, nor the clinical presentations of the patients. RESULTS: Of 21 patients' specimens that were tested for p16 by IHC, 11 specimens showed concordant results with the high-risk HPV 16/18 DNA ISH test. Whereas, in eight p16 IHC positive specimens, HPV viral DNA was not detected by HPV16/18 DNA ISH, and two specimens were not tested by DNA ISH. When these eight p16 IHC positive specimens with discrepant p16 IHC and DNA ISH results were further tested by DNA PCR, six specimens showed concordance with p16 IHC with positive results for HPV16 E7, while two specimens were negative for HPV16 E7 by DNA PCR. All tested specimens were negative for HPV18 E7 by DNA PCR. Thus, the addition of the HPV16 and HPV18 E7 DNA PCR test identified a significant number of false negative test results by the HPV16/18 DNA ISH test and likely several false positive results by p16 IHC. CONCLUSIONS: Inclusion of an HPV16 E7 DNA PCR test improved the robustness of HPV-associated OPSCC diagnosis in patients with discrepant results from p16 IHC staining and a DNA ISH test, and identified patients for proper management with less misclassification.

IL15 by Continuous Intravenous Infusion to Adult Patients with Solid Tumors in a Phase I Trial Induced Dramatic NK-Cell Subset Expansion.

PURPOSE: The first-in-human clinical trial with human bolus intravenous infusion IL15 (rhIL15) was limited by treatment-associated toxicity. Here, we report toxicity, immunomodulation, and clinical activity of rhIL15 administered as a 10-day continuous intravenous infusion (CIV) to patients with cancers in a phase I trial. PATIENTS AND METHODS: Patients received treatment for 10 days with CIV rhIL15 in doses of 0.125, 0.25, 0.5, 1, 2, or 4 µg/kg/day. Correlative laboratory tests included IL15 pharmacokinetic (PK) analyses, and assessment of changes in lymphocyte subset numbers. RESULTS: Twenty-seven patients were treated with rhIL15; 2 µg/kg/day was identified as the MTD. There were eight serious adverse events including two bleeding events, papilledema, uveitis, pneumonitis, duodenal erosions, and two deaths (one due to likely drug-related gastrointestinal ischemia). Evidence of antitumor effects was observed in several patients, but stable disease was the best response noted. Patients in the 2 µg/kg/day group had a 5.8-fold increase in number of circulating CD8+ T cells, 38-fold increase in total NK cells, and 358-fold increase in CD56bright NK cells. Serum IL15 concentrations were markedly lower during the last 3 days of infusion. CONCLUSIONS: This phase I trial identified the MTD for CIV rhIL15 and defined a treatment regimen that produced significant expansions of CD8+ T and NK effector cells in circulation and tumor deposits. This regimen has identified several biological features, including dramatic increases in numbers of NK cells, supporting trials of IL15 with anticancer mAbs to increase antibody-dependent cell-mediated cytotoxicity and anticancer efficacy.

Protection by universal influenza vaccine is mediated by memory CD4 T cells.

There is a diverse array of influenza viruses which circulate between different species, reassort and drift over time. Current seasonal influenza vaccines are ineffective in controlling these viruses. We have developed a novel universal vaccine which elicits robust T cell responses and protection against diverse influenza viruses in mouse and human models. Vaccine mediated protection was dependent on influenza-specific CD4+ T cells, whereby depletion of CD4+ T cells at either vaccination or challenge time points significantly reduced survival in mice. Vaccine memory CD4+ T cells were needed for early antibody production and CD8+ T cell recall responses. Furthermore, influenza-specific CD4+ T cells from vaccination manifested primarily Tfh and Th1 profiles with anti-viral cytokine production. The vaccine boosted H5-specific T cells from human PBMCs, specifically CD4+ and CD8+ T effector memory type, ensuring the vaccine was truly universal for its future application. These findings have implications for the development and optimization of T cell activating vaccines for universal immunity against influenza.