Profile of a serial killer: cellular and molecular approaches to study individual cytotoxic T-cells following therapeutic vaccination

The bright side of chemistry: Exploring synthetic peptide-based anticancer vaccines

The present review focuses on synthetic peptide-based vaccine strategies in the context of anticancer intervention, paying attention to critical aspects such as peptide epitope selection, adjuvant integration, and nuanced classification of synthetic peptide cancer vaccines. Within this discussion, we delve into the diverse array of synthetic peptide-based anticancer vaccines, each derived from tumor-associated antigens (TAAs), including melanoma antigen recognized by T cells 1 (Melan-A or MART-1), mucin 1 (MUC1), human epidermal growth factor receptor 2 (HER-2), tumor protein 53 (p53), human telomerase reverse transcriptase (hTERT), survivin, folate receptor (FR), cancer-testis antigen 1 (NY-ESO-1), and prostate-specific antigen (PSA). We also describe the synthetic peptide-based vaccines developed for cancers triggered by oncovirus, such as human papillomavirus (HPV), and hepatitis C virus (HCV). Additionally, the potential synergy of peptide-based vaccines with common therapeutics in cancer was considered. The last part of our discussion deals with the realm of the peptide-based vaccines delivery, highlighting its role in translating the most promising candidates into effective clinical strategies. Although this discussion does not cover all the ongoing peptide vaccine investigations, it aims at offering valuable insights into the chemical modifications and the structural complexities of anticancer peptide-based vaccines.

Virus-Like Particles as an Immunogenic Platform for Cancer Vaccines

Virus-like particles (VLP) spontaneously assemble from viral structural proteins. They are naturally biocompatible and non-infectious. VLP can serve as a platform for many potential vaccine epitopes, display them in a dense repeating array, and elicit antibodies against non-immunogenic substances, including tumor-associated self-antigens. Genetic or chemical conjugation facilitates the multivalent display of a homologous or heterologous epitope. Most VLP range in diameter from 25 to 100 nm and, in most cases, drain freely into the lymphatic vessels and induce antibodies with high titers and affinity without the need for additional adjuvants. VLP administration can be performed using different strategies, regimens, and doses to improve the immunogenicity of the antigen they expose on their surface. This article summarizes the features of VLP and presents them as a relevant platform technology to address not only infectious diseases but also chronic diseases and cancer.

Chronic Myelocytic Leukemia (CML) Patient-Derived Dendritic Cells Transfected with Autologous Total RNA Induces CML-Specific Cytotoxicity

The oncogenic bcr/abl1 fusion gene is a chronic myelogenous leukemia (CML)-specific antigen which is absent in normal tissues. This makes bcr/abl1 a perfect target for developing CML vaccines that elicit specific immune responses against minimal residual disease while sparing normal tissue. The aim of this study was to use different methods to induce dendritic cells (DCs) derived from patients with CML (CML-DCs) and analyze them for CML-specific tumor cytotoxicity for immune therapy. Bone marrow-derived mononuclear cells from ten CML patients were studied to induce CML-DC differentiation in the presence of recombinant human interleukin-4, rh-granulocyte-macrophage-colony stimulating factor, and tumor necrosis factor-alpha with either a total RNA-lipofectamine complex, total RNA or CML tumor lysate (freeze-thawed). CML-DC maturation, confirmed by expression of CD1α, CD40, CD80, CD83, CD86 and by real-time polymerase chain reaction, validated the CML-origin of these DC cells. CML-DCs stimulated cytotoxic T-cell (CTL) apoptosis, high levels of IL-12 secretion, and had significant inhibitory effect on K562 tumorigenicity in nude mice. CML-DCs pulsed with total RNA by lipofectamine transfection produced the strongest effect in tumor-specific CTL functions. These results indicate that CML-DCs transfected with total RNA by lipofectamine induce the strongest CTL cytotoxicity and have the greatest potential for CML immune therapy. This study holds promise for a DC-based strategy for inducing anti-leukemia responses and establishes a foundation for developing RNA vaccination against CML.

In Situ Staining and Laser Capture Microdissection of Lymph Node Residing SIV Gag-Specific CD8+ T cells--A Tool to Interrogate a Functional Immune Response Ex Vivo

While a plethora of data describes the essential role of systemic CD8⁺ T cells in the control of SIV replication little is known about the local in situ CD8⁺ T cell immune responses against SIV at the intact tissue level, due to technical limitations. In situ staining, using GagCM9 Qdot 655 multimers, were here combined with laser capture microdissection to detect and collect SIV Gag CM9 specific CD8⁺ T cells in lymph node tissue from SIV infected rhesus macaques. CD8⁺ T cells from SIV infected and uninfected rhesus macaques were also collected and compared to the SIV GagCM9 specific CD8⁺ T cells. Illumina bead array and transcriptional analyses were used to assess the transcriptional profiles and the three different CD8⁺ T cell populations displayed unique transcriptional patterns. This pilot study demonstrates that rapid and specific immunostaining combined with laser capture microdissection in concert with transcriptional profiling may be used to elucidate phenotypic differences between CD8⁺ T cells in SIV infection. Such technologies may be useful to determine differences in functional activities of HIV/SIV specific T cells.

Overcoming tumor immune evasion with an unique arbovirus

Combining dendritic cell vaccination with the adjuvant effect of a strain of dengue virus may be a way to overcome known tumor immune evasion mechanisms. Dengue is unique among viruses as primary infections carry lower mortality than the common cold, but secondary infections carry significant risk of hypovolemic shock. While current immuno-therapies rely on a single axis of attack, this approach combines physiological (hyperthermic reduction of tumor perfusion), immunological (activation of effector cells of the adaptive and innate immune system), and apoptosis-inducing pathways (sTRAIL) to destroy tumor cells. The premise of using multiple mechanisms of action in synergy with a decline in the ability of the tumor cells to employ resistance methods suggests the potential of this combination approach in cancer immunotherapy.

Vaccine-induced effector-memory CD8+ T cell responses predict therapeutic efficacy against tumors

CD8(+) T cells have the potential to attack and eradicate cancer cells. The efficacy of therapeutic vaccines against cancer, however, lacks defined immune correlates of tumor eradication after (therapeutic) vaccination based on features of Ag-specific T cell responses. In this study, we examined CD8(+) T cell responses elicited by various peptide and TLR agonist-based vaccine formulations in nontumor settings and show that the formation of CD62L(-)KLRG1(+) effector-memory CD8(+) T cells producing the effector cytokines IFN-γ and TNF predicts the degree of therapeutic efficacy of these vaccines against established s.c. tumors. Thus, characteristics of vaccine-induced CD8(+) T cell responses instill a predictive determinant for the efficacy of vaccines during tumor therapy.