Search

KRAS mutations hinder therapeutic efficacy of epidermal growth factor receptor (EGFR)‐specific monoclonal antibodies cetuximab and panitumumab‐based immunotherapy of EGFR+ cancers. Although cetuximab inhibits KRAS‐mutated cancer cell growth in vitro by natural killer (NK) cell‐mediated antibody‐dependent cellular cytotoxicity (ADCC), KRAS‐mutated colorectal carcinoma (CRC) cells escape NK cell immunosurveillance in vivo. To overcome this limitation, we used cetuximab and panitumumab to redirect Fcγ chimeric receptor (CR) T cells against KRAS‐mutated HCT116 colorectal cancer (CRC) cells. We compared four polymorphic Fcγ‐CR constructs including CD16158F‐CR, CD16158V‐CR, CD32131H‐CR, and CD32131R‐CR transduced into T cells by retroviral vectors. Percentages of transduced T cells expressing CD32131H‐CR (83.5 ± 9.5) and CD32131R‐CR (77.7 ± 13.2) were significantly higher than those expressing with CD16158F‐CR (30.3 ± 10.2) and CD16158V‐CR (51.7 ± 13.7) (p < 0.003). CD32131R‐CR T cells specifically bound soluble cetuximab and panitumumab. However, only CD16158V‐CR T cells released high levels of interferon gamma (IFNγ = 1,145.5 pg/ml ±16.5 pg/ml, p < 0.001) and tumor necrosis factor alpha (TNFα = 614 pg/ml ± 21 pg/ml, p < 0.001) upon incubation with cetuximab‐opsonized HCT116 cells. Moreover, only CD16158V‐CR T cells combined with cetuximab killed HCT116 cells and A549 KRAS‐mutated cells in vitro. CD16158V‐CR T cells also effectively controlled subcutaneous growth of HCT116 cells in CB17‐SCID mice in vivo. Thus, CD16158V‐CR T cells combined with cetuximab represent useful reagents to develop innovative EGFR+KRAS‐mutated CRC immunotherapies. What's new? KRAS mutations downstream the epidermal growth factor receptor (EGFR) represent the major limitation in monoclonal antibody‐targeted therapy of EGFR+ colorectal cancers. To restore the sensitivity of KRAS‐mutated cancer cells to EGFR‐specific mAbs, here the authors explore different strategies based on the generation of extracellular CD16‐chimeric receptors linked to intracellular signalling and subsequent transduction into T cells. They demonstrate that T cells engineered with CD16158V‐chimeric receptor can be redirected by EGFR‐specific mAbs toward EGFR+ cancer cells, overcoming the limitation conferred by KRAS mutations in vitro and in vivo. This study might help develop innovative and effective treatments of EGFR+ KRAS‐mutated cancers. [ABSTRACT FROM AUTHOR]

Central memory CD8+ T cells (TCM) play key roles in the protective immunity against infectious agents, cancer immunotherapy, and adoptive treatments of malignant and viral diseases. CD8+ TCM cells are characterized by specific phenotypes, homing, and proliferative capacities. However, CD8+ TCM-cell generation is challenging, and usually requires CD4+ CD40L+ T-cell 'help' during the priming of naïve CD8+ T cells. We have generated a replication incompetent CD40 ligand-expressing recombinant vaccinia virus (rVV40L) to promote the differentiation of human naïve CD8+ T cells into TCM specific for viral and tumor-associated antigens. Soluble CD40 ligand recombinant protein (sCD40L), and vaccinia virus wild-type (VV WT), alone or in combination, were used as controls. Here, we show that, in the absence of CD4+ T cells, a single 'in vitro' stimulation of naïve CD8+ T cells by rVV40L-infected nonprofessional CD14+ antigen presenting cells promotes the rapid generation of viral or tumor associated antigen-specific CD8+ T cells displaying TCM phenotypic and functional properties. These observations demonstrate the high ability of rVV40L to fine tune CD8+ mediated immune responses, and strongly support the use of similar reagents for clinical immunization and adoptive immunotherapy purposes. [ABSTRACT FROM AUTHOR]

Macrophages are key players in healing processes. However, little is known on their capacity to modulate the differentiation potential of mesenchymal stem/stromal cells (MSC). Here we investigated whether macrophages (Mf) with, respectively, pro-inflammatory and tissue-remodeling traits differentially modulate chondrogenesis of bone marrow derived-MSC (BM-MSC). We demonstrated that coculture in collagen scaffolds of BM-MSC with Mf derived from monocytes polarized with M-CSF (M-Mf), but not with GM-CSF (GM-Mf) resulted in significantly higher glycosaminoglycan (GAG) content than what would be expected from an equal number of BM-MSC alone (defined as chondro-induction). Moreover, type II collagen was expressed at significantly higher levels in BM-MSC/M-Mf as compared to BM-MSC/GM-Mf constructs, while type X collagen expression was unaffected. In order to understand the possible cellular mechanism accounting for chondro-induction, developing monoculture and coculture tissues were digested and the properties of the isolated BM-MSC analysed. We observed that as compared to monocultures, in coculture with M-Mf, BM-MSC decreased less markedly in number and exhibited higher clonogenic and chondrogenic capacity. Despite their chondro-inductive effect in vitro, M-Mf did not modulate the cartilage tissue maturation in subcutaneous pockets of nude mice, as evidenced by similar accumulation of type X collagen and calcified tissue. Our results demonstrate that coculture of BM-MSC with M-Mf results in synergistic cartilage tissue formation in vitro. Such effect seems to result from the survival of BM-MSC with high chondrogenic capacity. Studies in an orthotopic in vivo model are necessary to assess the clinical relevance of our findings in the context of cartilage repair. J. Cell. Physiol. 230: 1258-1269, 2015. © 2014 Wiley Periodicals, Inc., A Wiley Company [ABSTRACT FROM AUTHOR]

The prognosis of head and neck squamous cell carcinoma (HNSCC) patients remains poor. The identification of high-risk subgroups is needed for the development of custom-tailored therapies. The expression of cancer-testis antigens (CTAs) has been linked to a worse prognosis in other cancer types; however, their prognostic value in HNSCC is unclear because only few patients have been examined and data on CTA protein expression are sparse. A tissue microarray consisting of tumor samples from 453 HNSCC patients was evaluated for the expression of CTA proteins using immunohistochemistry. Frequency of expression and the subcellular expression pattern (nuclear, cytoplasmic, or both) was recorded. Protein expression of melanoma antigen (MAGE)-A family CTA, MAGE-C family CTA and NY-ESO-1 was found in approximately 30, 7 and 4% of tumors, respectively. The subcellular expression pattern in particular had a marked impact on the patients' prognosis. Median overall survival (OS) of patients with ( i) simultaneous cytoplasmic and nuclear expression compared to ( ii) either cytoplasmic or nuclear expression and ( iii) negative patients was 23.0 versus 109.0 versus 102.5 months, for pan-MAGE ( p < 0.0001), 46.6 versus 50.0 versus 109.0 for MAGE-A3/A4 ( p = 0.0074) and 13.3 versus 50.0 versus 100.2 months for NY-ESO-1 ( p = 0.0019). By multivariate analysis, these factors were confirmed as independent markers for poor survival. HNSCC patients showing protein expression of MAGE-A family members or NY-ESO-1 represent a subgroup with an extraordinarily poor survival. The development of immunotherapeutic strategies targeting these CTA may, therefore, be a promising approach to improve the outcome of HNSCC patients. [ABSTRACT FROM AUTHOR]

Mesenchymal stem/stromal cells (MSC) are multipotent precursors endowed with the ability to home to primary and metastatic tumor sites, where they can integrate into the tumor-associated stroma. However, molecular mechanisms and outcome of their interaction with cancer cells have not been fully clarified. In this study, we investigated the effects mediated by bone marrow-derived MSC on human colorectal cancer (CRC) cells in vitro and in vivo. We found that MSC triggered epithelial-to-mesenchymal transition (EMT) in tumor cells in vitro, as indicated by upregulation of EMT-related genes, downregulation of E-cadherin and acquisition of mesenchymal morphology. These effects required cell-to-cell contact and were mediated by surface-bound TGF-β newly expressed on MSC upon coculture with tumor cells. In vivo tumor masses formed by MSC-conditioned CRC cells were larger and characterized by higher vessel density, decreased E-cadherin expression and increased expression of mesenchymal markers. Furthermore, MSC-conditioned tumor cells displayed increased invasiveness in vitro and enhanced capacity to invade peripheral tissues in vivo. Thus, by promoting EMT-related phenomena, MSC appear to favor the acquisition of an aggressive phenotype by CRC cells. [ABSTRACT FROM AUTHOR]

Bladder cancer is a common urinary malignancy and a prevalent cause of cancer-related death. Current therapies of early stage non-muscle-invasive bladder cancer (NMIBC) are frequently associated with undesirable toxicities and recurrence. Active antigen-specific immunotherapy may provide a valid therapeutic option for patients with NMIBC. Cancer-testis antigens (CTA) expressed in various tumour types and in a limited range of healthy tissues may represent potential targets for specific immunotherapy. MAGE-A10 is probably the most immunogenic antigen of the MAGE-A family. We evaluated the expression of MAGE-A10 in NMIBC. Seventy-nine patients undergoing surgical treatment for NMIBC were enrolled in the study. MAGE-A10 gene expression was assessed by quantitative real-time polymerase chain reaction. Immunohistochemistry was performed on paraffin-embedded sections. MAGE-A10 gene was specifically expressed in one-third of NMIBC ( n = 24: 32.43%). Gene expression was correlated with high tumour grade. MAGE-A10 protein was exclusively detectable in nuclei of tumour cells. More importantly, MAGE-A10 protein was also more frequently detectable in high-grade tumours ( p = 0.0001) and in stage T1 tumours invading subepithelial tissue or lamina propria ( p = 0.01). A strong correlation between MAGE-A10 staining score and tumour grade and stage could accordingly be observed. These data indicate that MAGE-A10 expression is a feature of aggressive NMIBC and might be used as a novel target for specific immunotherapy of these cancers. [ABSTRACT FROM AUTHOR]

Herpes simplex virus protein ICP47, encoded by US12 gene, strongly downregulates major histocompatibility complex (MHC) class-I antigen restricted presentation by blocking transporter associated with antigen processing (TAP) protein. To decrease viral vector antigenic immunodominance and MHC class-I driven clearance, we engineered recombinant vaccinia viruses (rVV) expressing ICP47 alone (rVV-US12) or together with endoplasmic reticulum (ER)-targeted Melan-A/MART-127-35 model tumor epitope (rVV-MUS12). In this study, we show that antigen presenting cells (APC), infected with rVV-US12, display a decreased ability to present TAP dependent MHC class-I restricted viral antigens to CD8+ T-cells. While HLA class-I cell surface expression is strongly downregulated, other important immune related molecules such as CD80, CD44 and, most importantly, MHC class-II are unaffected. Characterization of rVV-MUS12 infected cells demonstrates that over-expression of a TAP-independent peptide, partially compensates for ICP47 induced surface MHC class-I downregulation (30% vs. 70% respectively). Most importantly, in conditions where clearance of infected APC by virus-specific CTL represents a limiting factor, a significant enhancement of CTL responses to the tumor epitope can be detected in cultures stimulated with rVV-MUS12, as compared to those stimulated by rVV-MART alone. Such reagents could become of high relevance in multiple boost protocols required for cancer immunotherapy, to limit vector-specific responsiveness. [ABSTRACT FROM AUTHOR]

Background Tumor markers are genes or their products expressed exclusively or preferentially in tumor cells and cancer-testis antigens (CTAs) form a group of genes with a typical expression pattern expressed in a variety of malignant neoplasms. CTAs are considered potential targets for cancer vaccines. It is possible that the CTA MAGE-A4 (melanoma antigen) and MAGE-C1 are expressed in carcinoma of the oral cavity and are related with survival. Methods This study involved immunohistochemical analysis of 23 patients with oral squamous cell carcinoma (SCC) and was carried out using antibodies for MAGE-A4 and MAGE-C1. Fisher's exact test and log-rank test were used to evaluate the results. Results The expression of the MAGE-A4 and MAGE-C1 were 56.5% and 47.8% without statistical difference in studied variables and survival. Conclusion The expression of at least 1 CTA was present in 78.3% of the patients, however, without correlation with clinicopathologic variables and survival. © 2011 Wiley Periodicals, Inc. Head Neck, 2012 [ABSTRACT FROM AUTHOR]

Mechanisms underlying cutaneous squamous cell carcinoma (SCC) tumour growth and invasion are incompletely understood. Our previous pathological and in vitro studies suggest that cell surface glycoprotein T-cadherin (T-cad) might be a controlling determinant of the behaviour of SCC. Here we used a murine xenograft model to determine whether T-cad modulates SCC tumour progression in vivo. Silencing or up-regulation of T-cad in A431 (shTcad or Tcad+, respectively) both resulted in increased tumour expansion in vivo. To explain this unanticipated outcome, we focused on proliferation, apoptosis and angiogenesis/lymphangiogenesis, which are important determinants of the progression of solid tumours in vivo. shTcad exhibited enhanced proliferation potential in vitro and in vivo, and their signalling response to EGF was characterized by a higher Erk1/2:p38MAPK activity ratio, which has been correlated with more aggressive tumour growth. T-cad over-expression did not affect proliferation but staining for cleaved caspase 3 revealed a minimal occurrence of extensive apoptosis in Tcad+ tumours. Immunofluoresence staining of xenograft sections revealed increased intra-tumoural total microvessel (CD31+) and lymphatic vessel (LYVE-1+) densities in Tcad+ tumours. shTcad tumours exhibited decreased microvessel and lymphatic densities. Tcad+ expressed higher levels of transcripts for VEGF-A, VEGF-C and VEGF-D in vitro and in vivo. Culture supernatants collected from Tcad+ enhanced sprout outgrowth from spheroids composed of either microvascular or lymphatic endothelial cells, and these in vitro angiogenic and lymphangiogenic responses were abrogated by inclusion of neutralizing VEGF antibodies. We conclude that T-cad can exert pleiotropic effects on SCC progression; up- or down-regulation of T-cad can promote SCC tumour expansion in vivo but through distinct mechanisms, namely enhancement of angio/lymphangiogenic potential or enhancement of proliferation capacity. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

MAGE-A10 is a highly immunogenic member of the MAGE-A family of cancer/testis tumor-associated antigens (C/T TAAs). Studies performed with broadly reactive antibodies have helped to initially characterize this TAA. However, no specific reagents have been developed so far, thus preventing a thorough analysis of its expression in healthy and tumoral tissues. We have produced MAGE-A10 gene product in soluble recombinant form, and we have used it to generate specific monoclonal antibodies (mAbs). One of these reagents, recognizing an epitope located at the COOH terminus of the MAGE-A10 gene product, was used to stain a multitumor tissue microarray comprising more than 2,500 paraffin-embedded specimens including healthy tissues, benign tumors and malignancies of different histological origin. MAGE-A10 protein was identified as an intranuclear protein of an apparent molecular weight of 70 kDa, expressed in normal spermatogonia and spermatocytes but in no other healthy tissue. Most importantly, this C/T TAA appears to be expressed in high (>50%) percentages of cancer cells from a number of malignancies, including lung, skin and urothelial tumors. Unexpectedly, high expression of MAGE-A10 TAA at the protein level was also detectable in gynecological malignancies and stomach and gall bladder cancers. The characterization of MAGE-A10-specific reagents might set the stage for the development of targeted active immunotherapy by clarifying potential indications and by allowing the selection of patients eligible for treatment and the monitoring of its effectiveness. [ABSTRACT FROM AUTHOR]

The article presents research on the role of tumor infiltration in the survival of patients with colorectal carcinoma (CRC). The significance of macrophage and natural killer (NK) cell infiltration in CRC is said to be still unclear. An investigation of the CRC innate inflammatory infiltrate was conducted and the survival time was assessed using the Kaplan-Meier method. It concludes that CD16+ cell infiltration showed favorable prognostic factor in CRC.

Background. Despite diagnostic and therapeutic advances in head and neck cancer, the 5-year survival of patients with laryngeal cancer has not improved in the last 30 years. Several recent studies indicate that specific targets for immunotherapeutic approaches can be useful in the control of cancer. There is considerable interest in the expression of cancer testis antigens in human cancers since they may serve as the basis for an immunologic approach to therapy. Methods. We evaluated by immunohistochemical analysis the expression of cancer testis antigens MAGE-A4 (57B), MAGE-C1 (CT7-33), MAGE-A1 (MA454), MAGE-A3 (M3H67), MAGE-C2 (CT10.5), NY-ESO-1 (E978), and GAGE (GAGE) in squamous cell carcinoma (SCC) of the larynx. Results. A total of 63 cases (57 men and 6 women) of laryngeal SCC were available for this study. The findings were correlated with the clinical course and laboratory data. Expression of at least 1 cancer testis antigen was detected in 42 of 63 of the laryngeal SCCs (67%). In 34 of 42 of the positive cases (81%) there was simultaneous expression of ≥2 cancer testis antigens. There was significant correlation between antigen expression and advanced tumor stage (stage III/IV) in cases with reactivity to only 1 antibody (p = .01) as well as in the cases with reactivity to ≥2 primary antibodies (≥2 mAbs, p = .04). There was no association between survival and expression of any of the analyzed antigens. Conclusions. We find a high incidence of cancer testis antigen expression in SCCs of the larynx, which was correlated with advanced clinical stage. Our data indicate that cancer testis antigens could be valuable vaccine targets in laryngeal tumors, especially in those with a worse prognosis. [ABSTRACT FROM AUTHOR]

The article presents information on a study which characterized the induction of human leukocyte antigen (HLA)-D related (DR) (HLA-DR) in human mesenchymal stem cells (MSC) by fibroblast growth factor (FGF), using interferon-γ (IFNγ) as the comparator for HLR-DR induction by an exogenous cytokine. A review of the related literature is offered. It investigates the roles of cell proliferation and growth factor-induced signaling pathways as well as class II major histocomptability complex (MHC) assembly machinery and functional capacity.

Background The prognostic value of cancer testis antigens in pharyngeal cancer is understudied. Methods We recruited 90 patients who were treated for pharyngeal cancer. Monoclonal antibodies 57B and B9.8.1.1 were used for detection of MAGE-A and NY-ESO-1 genes. Results MAGE-A and NY-ESO-1 gene products were detectable in 70.0% and 33.3% of pharyngeal tumors, respectively. No correlation was established between MAGE-A and NY-ESO-1 expression and TNM staging at presentation. Survival analysis showed a trend toward a shorter 5-year disease-free survival in the group of patients with MAGE-A–positive tumors (log-rank test, p = .122). In contrast, a trend toward a prolonged 5-year disease-free survival was observed in the group of patients with NY-ESO-1–positive tumors (log-rank test, p = .219). Conclusion In a large population of patients with pharyngeal cancer and available 5-year survival data, prognosis tended to be poorer with MAGE-A expression and better with NY-ESO-1 expression, but the correlations did not reach statistical significance. © 2009 Wiley Periodicals, Inc. Head Neck, 2010 [ABSTRACT FROM AUTHOR]

Human cytomegalovirus (HCMV) can cause life-threatening disease in infected hosts. Immunization with human leukocyte antigen (HLA)-restricted immunodominant synthetic peptides and adoptive transfer of epitope-specific T cells have been envisaged to generate or boost HCMV-specific cellular immunity, thereby preventing HCMV infection or reactivation. However, induction or expansion of T cells effective against HCMV are limited by the need of utilizing peptides with defined HLA restrictions. We took advantage of a combination of seven predictive algorithms to identify immunogenic peptides of potential use in the prevention or treatment of HCMV infection or reactivation. Here we describe a pp65-derived peptide (pp65340–355, RQYDPVAALFFFDIDL: RQY16-mer), characterized by peculiar features. First, RQY-16mer is able to stimulate HCMV pp65 specific responses in both CD4+ and CD8+ T cells, restricted by a wide range of HLA class I and II determinants. Second, RQY-16mer is able to induce an unusually wide range of effector functions in CD4+ T cells, including proliferation, killing of autologous HCMV-infected target cells and cytokine production. Third, and most importantly, the RQY-16mer is able to stimulate CD4+ and CD8+ T-cell responses in pharmacologically immunosuppressed patients. These data suggest that a single reagent might qualify as synthetic immunogen for potentially large populations exposed to HCMV infection or reactivation. [ABSTRACT FROM AUTHOR]

Abstract: This study addresses establishment of an “in vitro” melanoma angiogenesis model using multicellular tumor spheroids (MCTS) of differentiated (HBL) or undifferentiated (NA8) melanoma cell lines. DNA microarray assay and qRT-PCR indicated upregulation of pro-angiogenic factors IL-8, VEGF, Ephrin A1 and ANGPTL4 in NA8-MCTSs (vs. monolayers) whereas these were absent in MCTS and monolayer cultures of HBL. Upon co-culture with endothelial cell line HMEC-1 NA8-MCTS attract, whereas HBL-MCTS repulse, HMEC-1. Overexpression of T-cadherin in HMEC-1 leads to their increased invasion and network formation within NA8-MCTS. Given an appropriate angiogenic tumor microenvironment, T-cadherin upregulation on endothelial cells may potentiate intratumoral angiogenesis. [Copyright &y& Elsevier]

Production of indoleamine 2,3-dioxygenase (IDO) by tumor cells, leading to tryptophan depletion and production of immunosuppressive metabolites, may facilitate immune tolerance of cancer. IDO gene is also expressed in dendritic cells (DC) upon maturation induced by lipopolysaccarides or IFN. We investigated IDO gene expression in melanoma cell lines and clinical specimens as compared to mature DC (mDC). Furthermore, we explored effects of -kynurenine (L-kyn) and 3-hydroxyanthranilic acid (3-HAA) on survival and antigen-dependent and independent proliferation of CD8 cells. We observed that IDO gene expression in cultured tumor cells and freshly excised samples is orders of magnitude lower than in mDC, providing highly efficient antigen presentation to CD8 T cells. Non toxic concentrations of L-kyn or 3-HAA did not significantly inhibit antigen-specific CTL responses. However, 3-HAA, but not L-kyn markedly inhibited antigen-independent proliferation of CD8 T cells induced by common receptor γ-chain cytokines IL-2, -7 and -15. Our data suggest that CD8 T cell activation induced by antigenic stimulation, a function exquisitely fulfilled by mDC, is unaffected by tryptophan metabolites. Instead, in the absence of effective T cell receptor triggering, 3-HAA profoundly affects homeostatic proliferation of CD8 T cells. [ABSTRACT FROM AUTHOR]

Colorectal cancer (CRC) is a leading cause of cancer‐related death. Conventional chemotherapeutic regimens have limited success rates, and a major challenge for the development of novel therapies is the lack of adequate in vitro models. Nonmalignant mesenchymal and immune cells of the tumor microenvironment (TME) are known to critically affect CRC progression and drug responsiveness. However, tumor drug sensitivity is still evaluated on systems, such as cell monolayers, spheroids, or tumor xenografts, which typically neglect the original TME. Here, it is investigated whether a bioreactor‐based 3D culture system can preserve the main TME cellular components in primary CRC samples. Freshly excised CRC fragments are inserted between two collagen scaffolds in a "sandwich‐like" format and cultured under static or perfused conditions up to 3 d. Perfused cultures maintain tumor tissue architecture and densities of proliferating tumor cells to significantly higher extents than static cultures. Stromal and immune cells are also preserved and fully viable, as indicated by their responsiveness to microenvironmental stimuli. Importantly, perfusion‐based cultures prove suitable for testing the sensitivity of primary tumor cells to chemotherapies currently in use for CRC. Perfusion‐based culture of primary CRC specimens recapitulates TME key features and may allow assessment of tumor drug response in a patient‐specific context. [ABSTRACT FROM AUTHOR]

Human cytomegalovirus (HCMV) can cause life-threatening disease in infected hosts. Immunization with human leukocyte antigen (HLA)-restricted immunodominant synthetic peptides and adoptive transfer of epitope-specific T cells have been envisaged to generate or boost HCMV-specific cellular immunity, thereby preventing HCMV infection or reactivation. However, induction or expansion of T cells effective against HCMV are limited by the need of utilizing peptides with defined HLA restrictions. We took advantage of a combination of seven predictive algorithms to identify immunogenic peptides of potential use in the prevention or treatment of HCMV infection or reactivation. Here we describe a pp65-derived peptide (pp65(340-355), RQYDPVAALFFFDIDL: RQY16-mer), characterized by peculiar features. First, RQY-16mer is able to stimulate HCMV pp65 specific responses in both CD4(+) and CD8(+) T cells, restricted by a wide range of HLA class I and II determinants. Second, RQY-16mer is able to induce an unusually wide range of effector functions in CD4(+) T cells, including proliferation, killing of autologous HCMV-infected target cells and cytokine production. Third, and most importantly, the RQY-16mer is able to stimulate CD4(+) and CD8(+) T-cell responses in pharmacologically immunosuppressed patients. These data suggest that a single reagent might qualify as synthetic immunogen for potentially large populations exposed to HCMV infection or reactivation.