Activity of the HMGB1-derived immunostimulatory peptide Hp91 resides in the helical C-terminal portion and is enhanced by dimerization.

We have previously shown that an 18 amino acid long peptide, named Hp91, whose sequence corresponds to a region within the endogenous protein HMGB1, activates dendritic cells (DCs) and acts as adjuvant in vivo by potentiating Th1-type antigen-specific immune responses. We analyzed the structure-function relationship of the Hp91 peptide to investigate the amino acids and structure responsible for immune responses. We found that the cysteine at position 16 of Hp91 enabled formation of reversible peptide dimmers, monomer and dimmer were compared for DC binding and activation. Stable monomers and dimers were generated using a maleimide conjugation reaction. The dimer showed enhanced ability to bind to and activate DCs. Furthermore, the C-terminal 9 amino acids of Hp91, named UC1018 were sufficient for DC binding and Circular dichroism showed that UC1018 assumes an alpha-helical structure. The ninemer peptide UC1018 induced more potent antigen-specific CTL responses in vivo as compared to Hp91 and it protected mice from tumor development when used in a prophylactic vaccine setting. We have identified a short alpha helical peptide that acts as potent adjuvant inducing protective immune responses in vivo.

Clinical trials on CIK cells: first report of the international registry on CIK cells (IRCC).

PURPOSE: Recently, a subset of natural killer T lymphocytes termed "cytokine-induced killer (CIK) cells" has been described. To build an international registry, we collected the clinical data and treatment of patients with cancer using CIK cells from the literature and the respective investigators. This registry is expected to set a new set of standards on the reporting of results from clinical trials using CIK cells. A standardized reporting system will accelerate discoveries and allows us to improve treatment to benefit the patients. METHODS: We searched in PubMed for "CIK cells clinical trials". RESULTS: Within the 867 matches found, 11 clinical trials with CIK cells were identified. Within these trials, 426 patients were treated, of which 313 were male, and 113 were female. Most trials included male patients with hepatocellular carcinoma, gastric cancer, and Hodgkin or non-Hodgkin disease. In 10 of 11 studies, autologous CIK cells were used. The total number of CIK cells injected ranged from 21.9 × 10(7) to 5.2 × 10(10). The number of CIK cells used per infusion ranged from 7.2 × 10(6) to 2.1 × 10(10). Patients were treated with up to 40 infusions of CIK cells. Of the 384 patients, where a clinical response was reported, 24 patients showed a complete response, 27 patients showed a partial response, 40 patients showed a minor response. The total response rate (RR) was 91/384 reported patients, 161 patients had a stable disease, 129 patients had progressive disease. A decrease in tumor volume was only described in three patients. Side effects of CIK cell treatment were minor. Interestingly, a reduction of hepatitis B virus load was described in patients undergoing treatment with CIK cells. Disease-free survival rates were significantly higher in patients treated with CIK cells than in a control group without CIK treatment. CONCLUSION: Adjuvant immunotherapy with cytokine-induced killer cells may prevent recurrence and improve quality of life and progression-free survival rates in patients with cancer.

HMGB1-derived peptide acts as adjuvant inducing immune responses to peptide and protein antigen.

There is a need for new adjuvants that will induce immune responses to subunit vaccines. We show that a short peptide, named Hp91, whose sequence corresponds to an area within the endogenous molecule high mobility group box (HMGB1) protein 1 potentiates cellular immune responses to peptide antigen and cellular and humoral immune responses to protein antigen in vivo. Hp91 promoted the in vivo production of the immunomodulatory cytokines, IFN-γ, TNF-α, IL-6, and IL-12 (p70), as well as antigen-specific activation of CD8+ T cells. These results demonstrate the ability of a short immunostimulatory peptide to serve as an adjuvant for subunit vaccines.

Dendritic cells pulsed with alpha-galactosylceramide induce anti-tumor immunity against pancreatic cancer in vivo.

Ductal pancreatic adenocarcinoma is the fourth leading cause of cancer death in the Western world. Unfortunately, recent advances in diagnostics, staging and therapy have not resulted in significant improvements. Thus, new approaches are necessary to improve the outcome of patients with exocrine pancreatic cancer. We tested triggering of specific T lymphocytes in vivo by using the immunocompetent mouse strain C57BL/6. In the present study, we tried to enhance the anti-tumor effect against pancreatic carcinoma by supplementary triggering of NKT cells in vivo. We challenged Panc02 tumor-bearing mice by intratumoral vaccination with alpha-galactosylceramide (alpha-GalCer)-loaded dendritic cells (DCs). A significant expansion of IFNgamma-producing NKT cells was observed which also correlated with decrease in tumor growth in vivo. Hence, DCs loaded with alpha-GalCer could lead to a novel treatment option for patients with pancreatic cancer.

Human immunodeficiency virus type 1 Nef mediates activation of STAT3 in immature dendritic cells.

Replication of immunodeficiency viruses (HIV-1 and SIV) in immature dendritic cell (DC)-T cell cocultures is dependent on Nef. In contrast, mature DCs promote the replication of wild-type and nef-defective SIV in concert with CD4(+) T cells. Transcription factor activation occurs on DC maturation and this study aimed to investigate whether Nef triggers similar events in immature DCs, rendering them more like mature DCs. Recombinant HIV nef-expressing adenovirus was used to selectively introduce nef into immature human or macaque DCs. These data provide the first evidence that the expression of HIV nef in immature DCs induced selective activation of STAT3 and, to a lesser extent, NF-kappaB. This highlights how Nef can signal primary immature DCs, suggesting one way in which Nef may modulate immature DCs to drive virus replication in the DC-T cell milieu.

Requirement of mature dendritic cells for efficient activation of influenza A-specific memory CD8+ T cells.

It is critical to identify the developmental stage of dendritic cells (DCs) that is most efficient at inducing CD8+ T cell responses. Immature DCs can be generated from monocytes with GM-CSF and IL-4, while maturation is accomplished by the addition of stimuli such as monocyte-conditioned medium, CD40 ligand, and LPS. We evaluated the ability of human monocytes and immature and mature DCs to induce CD8+ effector responses to influenza virus Ags from resting memory cells. We studied replicating virus, nonreplicating virus, and the HLA-A*0201-restricted influenza matrix protein peptide. Sensitive and quantitative assays were used to measure influenza A-specific immune responses, including MHC class I tetramer binding assays, enzyme-linked immunospot assays for IFN-gamma production, and generation of cytotoxic T cells. Mature DCs were demonstrated to be superior to immature DC in eliciting IFN-gamma production from CD8+ effector cells. Furthermore, only mature DCs, not immature DCs, could expand and differentiate CTL precursors into cytotoxic effector cells over 7 days. An exception to this was immature DCs infected with live influenza virus, because of the virus's known maturation effect. Finally, mature DCs pulsed with matrix peptide induced CTLs from highly purified CD8+ T cells without requiring CD4+ T cell help. These differences between DC stages were independent of Ag concentrations or the number of immature DCs. In contrast to DCs, monocytes were markedly inferior or completely ineffective stimulators of T cell immunity. Our data with several qualitatively different assays of the memory CD8+ T cell response suggest that mature cells should be considered as immunotherapeutic adjuvants for Ag delivery.

The decreased replicative capacity of simian immunodeficiency virus SIVmac239Delta(nef) is manifest in cultures of immature dendritic cellsand T cells.

Transmission of simian immunodeficiency virus SIVmac239Delta(nef) (Delta(nef)) to macaques results in attenuated replication of the virus in most animals and ultimately induces protection against challenge with some pathogenic, wild-type SIV strains. It has been difficult, however, to identify a culture system in which the replication of Delta(nef) is severely reduced relative to that of the wild type. We have utilized a primary culture system consisting of blood-derived dendritic cells (DCs) and autologous T cells. When the DCs were fully differentiated or mature, the DC-CD4(+) T-cell mixtures supported replication of both the parental SIV strain, 239 (the wild type), and its mutant with nef deleted (Delta(nef)), irrespective of virus dose and the cell type introducing the virus to the coculture. In contrast, when immature DCs were exposed to Delta(nef) and cocultured with T cells, virus replication was significantly lower than that of the wild type. Activation of the cultures with a superantigen allowed both Delta(nef) and the wild type to replicate comparably in immature DC-T-cell cultures. Immature DCs, which, it has been hypothesized, capture and transmit SIV in vivo, are deficient in supporting replication of Delta(nef) in vitro and may contribute to the reduced pathogenicity of Delta(nef) in vivo.

[Retinal detachment]. / Netzhautablösung.

Retinal detachment can be successfully treated today in over 90% of patients. For a good functional prognosis early diagnosis and appropriate initial treatment remain crucial. Symptoms of incipient retinal detachment are those of acute posterior detachment of the vitreous body with "mouches volantes" and/or photopsia. At risk and thus to be examined urgently if such symptoms occur are patients with previous history of detachment, severe myopia, aphakia or pseudophakia. Prophylactic treatment of degenerative retinal lesions that can be interpreted as precursors of detachment is highly controversial and only indicated in patients with particular risk factors. Research in surgical treatment of retinal detachment focuses on improvement of functional result by improved instruments and standardized operative techniques.