Scant activation of CD8 T?cells by antigen loaded on heat shock protein

In Situ Upregulating Heat Shock Protein 70 via Gastric Nano-Heaters for the Interference of Helicobacter pylori Infection

Taking inspiration from the mechanism of Helicobacter pylori infection can lead to innovative antibacterial ways to fight antibiotics resistance. Herein, a gastric nano-heater iron-cobalt alloy shielded with graphitic shells (FeCo@G) is developed to interfere with H. pylori infection under an alternating magnetic field. FeCo@G shows a high and stable specific loss power (SLP = 534.1 W g^-1) in the acidic environment and provides efficient magnetothermal stimulation in the stomach. Such stimulation upregulates the cytoprotective heat shock protein 70 (HSP70) in gastric epithelial cells, which antagonizes the infection of H. pylori. This finding is further supported by the transcriptomic analysis verifying the upregulation of HSP70 in the stomach. Moreover, the nano-heater shows a high inhibition rate of H. pylori in vivo with good biocompatibility; 95% of FeCo@G is excreted from the mouse's gastrointestinal tract within 12 h. In summary, FeCo@G allows magnetothermal therapy to be used in harsh gastric environments, providing an approach for the therapy against H. pylori.

Immunostimulatory effects of Leishmania infantum HSP70 recombinant protein on dendritic cells in vitro and in vivo

Background: Activation of dendritic cells (DCs) has an important role in immunity against Leishmania. Aim: We investigated the effect of Leishmania infantum (L. infantum) heat shock protein 70 recombinant protein (rHSP70) as a vaccine on DC maturation and function. Materials & methods: BALB/c mouse splenic DCs were isolated and treated with different concentrations of rHSP70. Maturation markers, cytokine production and capability of DCs to proliferate allogeneic T cells were evaluated. Furthermore, this recombinant protein was injected into BALB/c mice, and expression of CD86, CD40 and MHC class II molecules by their splenic DCs were evaluated. Results: rHSP70 significantly increases the production of IL-12p70 by DCs. It had no effect on allogeneic T-cell proliferation in mixed lymphocyte reaction. It increased IFN-γ and decreased IL-4 cytokine level in mixed lymphocyte reaction supernatant. The in vitro study showed that rHSP70 had no significant effect neither on the percentage of CD40+, CD86+ and MHC class II+ DCs nor on the mean fluorescent intensity. However, in vivo results showed that rHSP70 increases the percentage of CD86-, CD40- and MHC class II-expressing cells as well as mean fluorescent intensity of CD40 and MHC class II. Conclusion: This study demonstrated the capability of L. infantum-derived rHSP70 in maturating BALB/c mice splenic DCs and in vivo polarization of immunity to a Th1 response.

A heat shock protein based polyvalent vaccine targeting HSV-2: CD4(+) and CD8(+) cellular immunity and protective efficacy

Efforts to develop a subunit vaccine against genital herpes have been hampered by lack of knowledge of the protective antigens of HSV-2, the causative agent of the disease. Vaccines based either on selected antigens or attenuated live virus approaches have not demonstrated meaningful clinical activity. We present here results of a therapeutic vaccine candidate, HerpV (formerly called AG-707), consisting of 32 HSV-2 peptides derived from 22 HSV-2 proteins, complexed non-covalently to the HSP70 chaperone and formulated with QS-21 saponin adjuvant. HerpV is observed to be immunogenic, generating CD4(+) and CD8(+) T cell responses in three mouse strains including HLA-A2 transgenic mice. Optimal T cell stimulation was dependent on the synergistic adjuvant properties of QS-21 with hsp70. The vaccine provided significant protection from viral challenge in a mouse prophylaxis model and showed signals of activity in a guinea pig therapeutic model of existing infection. Peripheral blood mononuclear cells from human HSV-2(+) subjects also showed reactivity in vitro to a subset of individual peptides and to the pool of all 32 peptides. Recombinant human Hsc70 complexed with the 32 peptides also stimulated the expansion of CD8(+) T cells from HSV-2(+) subjects in vitro. These studies demonstrate that HerpV is a promising immunotherapy candidate for genital herpes, and provide a foundation for evaluating HerpV in human HSV-2(+) subjects with the intent of eliciting CD4(+) and CD8(+) T cell responses to a broad array of viral antigens.

Ito Cells Are Liver-Resident Antigen-Presenting Cells for Activating T Cell Responses

Here we identified Ito cells (hepatic stellate cells, HSC), known for storage of vitamin A and participation in hepatic fibrosis, as professional liver-resident antigen-presenting cells (APC). Ito cells efficiently presented antigens to CD1-, major histocompatibility complex (MHC)-I-, and MHC-II-restricted T cells. Ito cells presented lipid antigens to CD1-restricted T lymphocytes such as natural killer T (NKT) cells and promoted homeostatic proliferation of liver NKT cells through interleukin-15. Moreover, Ito cells presented antigenic peptides to CD8(+) and CD4(+) T cells and mediated crosspriming of CD8(+) T cells. Peptide-specific T cells were activated by transgenic Ito cells presenting endogenous neoantigen. Upon bacterial infection, Ito cells elicited antigen-specific T cells and mediated protection. In contrast to other liver cell types that have been implicated in induction of immunological tolerance, our data identify Ito cells as professional intrahepatic APCs activating T cells and eliciting a multitude of T cell responses specific for protein and lipid antigens.

Heat shock proteins as vaccine adjuvants in infections and cancer

In addition to maintaining cell homeostasis under physiological and stress conditions, some heat shock proteins (HSPs) are potent inducers of immunity and have been harnessed as vaccine adjuvants targeted to cancers and infections. HSPs are a group of ubiquitous intracellular molecules that function as molecular chaperones in numerous processes, such as protein folding and transport, and are induced under stress conditions, such as fever and radiation. Certain HSPs are potent inducers of innate and antigen-specific immunity. They activate dendritic cells partly through toll-like receptors, activate natural killer cells, increase presentation of antigens to effector cells and augment T-cell and humoral immune responses against their associated antigens. Their roles in priming multiple host defense pathways are being exploited in vaccine development for cancer and infectious diseases.

Evaluation of antibody responses elicited by immunization of mice with a pneumococcal antigen genetically fused to murine HSP70 and murine interleukin-4

The heat shock (stress) protein HSP70 has been shown to be a potent stimulator of cellular immune responses. In order to determine whether HSP70 has the ability to stimulate antibody responses, we constructed and expressed fusion proteins consisting of murine HSP70 or murine interleukin (IL)-4 covalently linked to a pneumococcal cell wall-associated protein antigen designated PpmA. Immunization of mice with the PpmA-HSP70 fusion protein (PpmA-70) failed to elicit an increased PpmA-specific serum antibody response. In contrast, mice immunized with PpmA fused to IL-4 (PpmA-IL4), or PpmA fused to both IL-4 and HSP70 (PpmA-IL4-70) fusion proteins elicited high levels of PpmA-specific antibody responses. These data suggest that HSP70 has a limited capacity to stimulate immune responses to heterologous antigens in vivo.