Endogenously expressed matrix protein M1 and nucleoprotein of influenza A are efficiently presented by class I and class II major histocompatibility complexes.

Current influenza vaccines containing primarily hypervariable haemagglutinin and neuraminidase proteins must be prepared against frequent new antigenic variants. Therefore, there is an ongoing effort to develop influenza vaccines that also elicit strong and sustained cytotoxic responses against highly conserved determinants such as the matrix (M1) protein and nucleoprotein (NP). However, their antigenic presentation properties in humans are less defined. Accordingly, we analysed MHC class I and class II presentation of endogenously processed M1 and NP in human antigen presenting cells and observed expansion of both CD8(+)- and CD4(+)-specific effector T lymphocytes secreting gamma interferon and tumour necrosis factor. Further enhancement of basal MHC-II antigenic presentation did not improve CD4(+) or CD8(+) T-cell quality based on cytokine production upon challenge, suggesting that endogenous M1 and NP MHC-II presentation is sufficient. These new insights about T-lymphocyte expansion following endogenous M1 and NP MHC-I and -II presentation will be important to design complementary heterosubtypic vaccination strategies.

A Randomized Controlled Study to Evaluate the Safety and Reactogenicity of a Novel rVLP-Based Plant Virus Nanoparticle Adjuvant Combined with Seasonal Trivalent Influenza Vaccine Following Single Immunization in Healthy Adults 18-50 Years of Age.

Inactivated influenza vaccines efficacy is variable and often poor. We conducted a phase 1 trial (NCT02188810), to assess the safety and immunogenicity of a novel nanoparticle Toll-like receptor 7/8 agonist adjuvant (Papaya Mosaic Virus) at different dose levels combined with trivalent influenza vaccine in healthy persons 18-50 years of age. Hemagglutination-inhibition assays, antibody to Influenza A virus nucleoprotein and peripheral blood mononuclear cells for measurement of interferon-gamma ELISPOT response to influenza antigens, Granzyme B and IFNγ:IL-10 ratio were measured. The most common adverse events were transient mild to severe injection site pain and no safety signals were observed. A dose-related adjuvant effect was observed. Geometric mean hemagglutination-inhibition titers increased at day 28 in most groups and waned over time, but fold-antibody responses were poor in all groups. Cell mediated immunity results were consistent with humoral responses. The Papaya Mosaic Virus adjuvant in doses of 30 to 240 µg combined with reduced influenza antigen content was safe with no signals up to 3 years after vaccination. A dose-related adjuvant effect was observed and immunogenicity results suggest that efficacy study should be conducted in influenza antigen-naïve participants.

Stimulation of Wnt/ß-catenin pathway in human CD8+ T lymphocytes from blood and lung tumors leads to a shared young/memory phenotype.

Cancer can be treated by adoptive cell transfer (ACT) of T lymphocytes. However, how to optimally raise human T cells to a differentiation state allowing the best persistence in ACT is a challenge. It is possible to differentiate mouse CD8(+) T cells towards stem cell-like memory (T(SCM)) phenotype upon TCR stimulation with Wnt/ß-catenin pathway activation. Here, we evaluated if T(SCM) can be obtained from human mature CD8(+) T cells following TCR and Wnt/ß-catenin activation through treatment with the chemical agent 4,6-disubstituted pyrrolopyrimidine (TWS119), which inhibits the glycogen synthase kinase-3ß (GSK-3ß), key inhibitor of the Wnt pathway. Human CD8(+) T cells isolated from peripheral blood or tumor-infiltrating lymphocytes (TIL), and treated with TWS119 gave rise to CD62L(+)CD45RA(+) cells, indicative of early differentiated stage, also expressing CD127 which is normally found on memory cells, and CD133, an hematopoietic stem cell marker. T(SCM) cells raised from either TIL or blood secreted numerous inflammatory mediators, but in lower amounts than those measured without TWS119. Finally, generated T(SCM) CD8(+) T cells expressed elevated Bcl-2 and no detectable caspase-3 activity, suggesting increased persistence. Our data support a role for Wnt/ß-catenin pathway in promoting the T(SCM) subset in human CD8(+) T cells from TIL and the periphery, which are relevant for ACT.

Phenotypic characterization and functional analysis of human tumor immune infiltration after mechanical and enzymatic disaggregation.

Multi-parametric flow cytometry analysis is a reliable method for phenotypic and functional characterization of tumor infiltrating immune cells (TIIC). The isolation of infiltrating leukocytes from solid tumors can be achieved through various methods which can be both enzymatic and mechanical; however, these methods may alter cell biology. The aim of this study was to compare the effects of three tissue disaggregation techniques on TIIC biology in breast, kidney and lung tumor specimens. We therefore compared two enzymatic treatments using either collagenase type IA alone or in combination with collagenase type IV and DNase I type II, and one mechanical system (Medimachine™). We evaluated the impact of treatments on cell viability, surface marker integrity and proliferative capacity. We show that cell viability was not significantly altered by treatments. However, enzymatic treatments decreased cell proliferation; specifically collagenases and DNase provoked a significant decrease in detection of surface markers such as CD4, CD8, CD45RA and CD14, indicating that results of phenotypic studies employing these techniques could be affected. In conclusion, mechanical tissue disaggregation by Medimachine™ appears to be optimal to maintain phenotypic and functional TIIC features.