Activation of Innate and Adaptive Immunity by a Recombinant Human Cytomegalovirus Strain Expressing an NKG2D Ligand.

Development of an effective vaccine against human cytomegalovirus (HCMV) is a need of utmost medical importance. Generally, it is believed that a live attenuated vaccine would best provide protective immunity against this tenacious pathogen. Here, we propose a strategy for an HCMV vaccine that aims at the simultaneous activation of innate and adaptive immune responses. An HCMV strain expressing the host ligand ULBP2 for the NKG2D receptor was found to be susceptible to control by natural killer (NK) cells, and preserved the ability to stimulate HCMV-specific T cells. Infection with the ULBP2-expressing HCMV strain caused diminished cell surface levels of MHC class I molecules. While expression of the NKG2D ligand increased the cytolytic activity of NK cells, NKG2D engagement in CD8+ T cells provided co-stimulation and compensated for lower MHC class I expression. Altogether, our data indicate that triggering of both arms of the immune system is a promising approach applicable to the generation of a live attenuated HCMV vaccine.

Understanding the functional relevance of oral neutrophils, phenotype and properties in OSCC.

Neutrophils are the predominant white blood cells (WBC) that are recruited to the sites of inflammation and infection. They are acknowledged to perform dual roles by promoting (pro-tumor) or by exhibiting anti-cancer properties (anti-tumor). Neutrophils are characterized based on the changes in phenotype and functional properties. To this context, circulating polymorphonuclear neutrophils (cPMN) and tumor-associated neutrophils (TANs) in cancer biology has been well explored but limited to oral polymorphonuclear neutrophils (oPMNs) in oral squamous cell carcinoma (OSCC). However, oPMNs are eminent in maintaining the healthy oral ecosystem by neutralizing microorganisms. Neutralization process enhances the expression of cell surface markers (CD11b, CD63, CD66, CD66b, CD66c, and CD66e) and inflammatory cytokines (TNF-α, IFN-γ, GM-CSF, and IL-8) and increases the recruitment of neutrophils. Along with the inflammation, it has been reported that CEACAM1 and chemerin also favors the infiltration of neutrophils to the cancer site. This indicates that oPMN might contribute to the aetiology of OSCC. The main objective of this review is to explore, the production and migration of oPMNs to the oral cavity, their phenotypes and possible role in OSCC.

Multimer monitoring of CMV-specific T cells in research and in clinical applications.

Multimer monitoring has become a standard technique for detection of antigen-specific T cells. The term "multimer" refers to a group of reagents based on the multimerisation of molecules in order to raise avidity and thus stabilize binding to their ligand. Multimers for detection of antigen-specific T-cell responses are based on major histocompatibility complex class I peptide complexes. Multimer staining enables fast and direct visualization of antigen-specific T cells; thus, it is widely applied to assess antiviral immunity, e.g., monitor patients in vaccination trials or confirm purity of cell products for adoptive transfer. Assessment of T-cell immunity against persistent pathogens like cytomegalovirus (CMV) is of major importance in immunosuppressed patients. Recent advancements of multimers facilitate reversible labeling and allow isolation of epitope-specific T cells for adoptive transfer. Here, we give an overview on the different multimers and their applications, with an emphasis on CMV-specific T-cell responses.

Impaired functionality of antiviral T cells in G-CSF mobilized stem cell donors: implications for the selection of CTL donor.

Adoptive transfer of antiviral T cells enhances immune reconstitution and decreases infectious complications after stem cell transplantation. Information on number and function of antiviral T cells in stem cell grafts is scarce. We investigated (1) immunomodulatory effects of G-CSF on antiviral T cells, (2) the influence of apheresis, and (3) the optimal time point to collect antiviral cells. CMV-, EBV- and ADV-specific T cells were enumerated in 170 G-CSF-mobilized stem cell and 24 non-mobilized platelet donors using 14 HLA-matched multimers. T-cell function was evaluated by IFN-γ ELISpot and granzyme B secretion. Immunophenotyping was performed by multicolor flow cytometry. G-CSF treatment did not significantly influence frequency of antiviral T cells nor their in vitro expansion rate upon antigen restimulation. However, T-cell function was significantly impaired, as expressed by a mean reduction in secretion of IFN-γ (75% in vivo, 40% in vitro) and granzyme B (32% target-independent, 76% target-dependent) as well as CD107a expression (27%). Clinical follow up data indicate that the first CMV-reactivation in patients and with it the need for T-cell transfer occurs while the donor is still under the influence of G-CSF. To overcome these limitations, T-cell banking before mobilization or recruitment of third party donors might be an option to optimize T-cell production.