Heat shock fusion protein gp96-Ig mediates strong CD8 CTL expansion in vivo

PROBLEM: As shown previously, gp96-Ig peptide complexes secreted by an ovalbumin transfected tumor (EG7) mediate strong, specific tumor immunity through a CD4 T cell independent CD8+ CTL response. In this study, we set out to develop a system to quantitatively determine the CD8 CTL response to gp96-Ig and to evaluate the influence of an established wild type tumor. METHODS: Secreted heat shock protein gp96-Ig was constructed by replacement of the endoplasmic reticulum retention signal with the Fc portion of IgGI, transfected into EG7 (EG7-gp96-Ig) and used to induce CD8+ CTL expansion in vivo. Adoptively transferred, ovalbumin specific T-cell receptor (TCR) transgenic CD8+ cells (OT-1) responded with clonal expansion to the immunization with EG7-gp96-Ig. OT-1 expansion was quantitated with K(b-peptide)-tetramers by flow cytometry. RESULTS: In response to primary immunization with EG7-gp96-Ig, OT-1 expand from an initial frequency of 0.5 to 25% of all CD8 cells, and to 50% of all CD8 cells after a booster immunization. Endogenous ovalbumin specific CD8 cells also expand strongly. Antigen specific effector function was measured by enzyme-linked immunosorbent spot-forming cell assay (ELISPOT) for interferon-gamma (IFN-gamma). While effector function was strongly induced by secreted gp96-Ig, not all expanded OT-1 produce IFN-gamma. EG7 does not cause OT-1 expansion, but rather induces anergy. If OT-1 are transferred into wild type EG7 tumor bearing mice to induce anergy of OT-1, immunization with EG7-gp96-Ig can partly overcome unresponsiveness. CONCLUSIONS: We conclude that secreted gp96-Ig is a powerful mediator of specific CD8+ CTL responses in vivo. Secretory gp96 mimics release of gp96 by damaged or necrotic cells that is able to activate dendritic cells without CD4 help. Gp96-Ig associated peptides have not been selected by binding to major histocompatibility complex (MHC). Specific immunization by secreted gp96-Ig therefore is expected to occur also in allogeneic settings.     

Heat shock proteins and immunotherapy

Heat shock proteins (HSPs) were discovered in1962. Their names originated from the observationthat their expression was induced after cells wereexposed to elevated temperature. Being the mostabundant and ubiquitous soluble intracellular pro teins, they are present in all prokaryotic and eu karyotic cell types and are considered essential tothe survival of cells due to their multiple house keeping functions. These functions include: fold ing and unfolding of proteins, degradation of pro t…     

热休克蛋白与动脉粥样硬化

脉粥样硬化(atherosclerosis, AS)是一种发生在血管内膜表面由于结构异常以及代谢紊乱而导致的疾病.     

Heat shock protein-based cancer vaccines

Heat shock proteins (HSPs) exist ubiquitously across all species and function as chaperones stabilizing and delivering peptides. Tumor-derived HSP-peptide complex has been known to induce immunity against the original tumor in preclinical studies. HSP-based vaccines work across tumor types and bypass the need for identifying the responsible peptide(s) for inducing immunity. These vaccines are tumor- and patient-specific in that they capture the tumor cells' fingerprints. HSP-based vaccines have been studied in early phase clinical trials, mostly using HSP glycoprotein 96, for various types of malignancies including melanoma, renal cell carcinoma, gastric cancer, pancreatic cancer, low-grade lymphoma, colorectal cancer and chronic myelogenous leukemia. All showed minimal toxicity and potential efficacy. Phase III studies for melanoma and renal cell carcinoma are ongoing. HSP-based vaccines are a novel vaccine preparation with a promising role in cancer management. Further studies to determine the administering strategy and specific indication are warranted.     

Cytokine-induced neutrophil-derived interleukin-8.

During acute inflammation, the first line of cellular response for host defense is the neutrophil. In addition to the historic role of the neutrophil as a phagocyte, recent studies have identified this cell as an important source of a number of cytokines. In this study, we provide evidence that the neutrophil is a significant source of interleukin-8 (IL-8). Neutrophils freshly isolated from whole blood were not found to constitutively express IL-8 mRNA. In contrast, when these leukocytes were cultured on plastic they were activated, leading to the significant expression of de novo steady-state levels of IL-8 mRNA. In addition, when neutrophils were treated with cycloheximide, there was evidence for "superinduction" of steady-state levels of IL-8 mRNA and inhibition of antigenic IL-8 production. Neutrophils were subsequently stimulated with lipopolysaccharide (LPS), tumor necrosis factor-alpha, or interleukin-1-beta and were found to express IL-8 mRNA and antigen in both a time- and dose-dependent manner. Furthermore, neutrophils stimulated with traditional chemotactic/activating factors, such as the split product of the fifth component of complement (C5a), formylmethionyleucylphenylalanine (fMLP), and leukotriene B4 (LTB4) in a dose-dependent manner did not produce significant antigenic IL-8, as compared with unstimulated controls. In contrast, when neutrophils were exposed to either of these neutrophil agonists in the presence of LPS, the production of antigenic IL-8 was significantly elevated, as compared with either of the stimuli alone, suggesting a synergistic response. These data would suggest that the neutrophil can no longer be viewed as only a phagocyte or warehouse for proteolytic enzymes, but is a pivotal effector cell that is able to respond to mediators in its environment and generate cytokines. This latter neutrophil response may be important for either the elicitation of additional neutrophils or to orchestrate the conventional immune response at sites of inflammation.     

Heat shock response of spirochetes.

We examined the heat shock response of the pathogenic spirochetes Treponema pallidum, Borrelia burgdorferi, and Leptospira interrogans and certain saprophytic spirochetes. Cellular proteins synthesized after shifts to higher temperatures were [35S]methionine labeled and analyzed by gel electrophoresis and fluorography. Only T. pallidum failed to exhibit an obvious heat shock response. GroEL and DnaK homologs were identified in the various species, although these proteins were not thermoinducible in T. pallidum or Treponema denticola. DNA hybridization studies indicate that spirochetal groEL and dnaK genes are highly conserved.     

Heat shock proteins as vaccine candidates

Parasite heat shock proteins are phylogenetically well-conserved antigenic mosaics that nonetheless stimulate both humoral and cellular immune responses during the course of infection. These range from highly specific to broadly cross-reactive, with intermediate degrees also documented. The latter may prove beneficial, if they can be appropriately channelled to protect against multiple pathogens, or potentially harmful, if they cross-react with host components. Assessment of heat shock proteins as vaccine candidates has thus proceeded cautiously, with efforts being made to map the specificity of host immune responses to individual epitopes of the molecules. Ultimately, to serve as vaccines, the molecules must be recognized by the immune system within the context of a living pathogen, and be capable of inducing appropriate cellular and/or humoral immune responses that are effective at preventing establishment of individual pathogens. Reviewed are studies relevant to the use of parasite hsps as vaccine components, with emphasis on those from schistosomes, malaria, chlamydial, and mycobacterial parasites.     

Heat shock proteins and cancer immunotherapy

Vaccination with heat shock proteins from tumor have been shown to elicit an anti-tumor response. Current studies indicate that the immunogenecity of HSPs is derived from the antigenic peptides which they associate with. Mechanisms by which the HSP-peptide complexes induce an immune response and the possible role of HSPs in antigen presentation is discussed in this article. The use of HSP-peptide complexes can be used as tumor vaccines for cancer immunotherapy is reviewed.     

Heat shock phenomena in Aspergillus nidulans

Summary Heat shock was found to induce characteristic changes in the pattern of protein synthesis in Aspergillus nidulans as analysed by SDS-polyacrylamide gel electrophoresis. Six to seven new bands were found to show increased incorporation to ³⁵S-methionine at 43 °C compared to 37 °C, the standard temperature for this organism. The heat shock response of five different strains of A. nidulans was examined. This comparative study showed that these strains (haploids and diploids) show exactly the same set of heat shock proteins.     

Heat shock protein and innate immunity

In addition to serving as molecular chaperones,heat shock proteins (HSPs) have been implicated inautoimmune diseases,antigen presentation and tumor immunity.Extensive work in the last 10 years has alsosuggested that HSPs such as Hsp60,Hsp70,Hsp90 and gp96,may be potent activators of the innate immunesystem capable of inducing the production of pro-inflammatory cytokines by the monocyte-macrophage system,and the activation and maturation of dendritic cells via the Toll-like receptor 2 and 4 signal transductionpathways.However,recent evidence suggests that the reported cytokine effects of HSPs may be a result of thecontaminating bacterial cell-wall products.This concise review summarizes the current controversy over therole of HSPs in innate immunity.Cellular & Molecular Immunology.2004;1(4):274-279.