Efficacy and Safety of the Heat Shock Protein 90 Inhibitor RGRN-305 in Hidradenitis Suppurativa: A Parallel-Design Double-Blind Trial.

Importance: Hidradenitis suppurativa is a painful immune-mediated disorder with limited treatment options; hence, a need exists for new treatments. Objective: To evaluate the feasibility of heat shock protein 90 inhibition by RGRN-305 as a novel mechanism of action in treating moderate to severe hidradenitis suppurativa. Design, Setting, and Participants: This was a parallel-design, double-blind, proof-of-concept, placebo-controlled randomized clinical trial conducted between September 22, 2021, and August 29, 2022, at the Department of Dermatology, Aarhus University Hospital in Denmark. The study included a 1- to 30-day screening period, a 16-week treatment period, and a 4-week follow-up period. Eligibility criteria included age 18 years or older and moderate to severe hidradenitis suppurativa with 6 or more inflammatory nodules or abscesses in at least 2 distinct anatomic regions. Of 19 patients screened, 15 patients were enrolled in the study. Intention-to-treat analysis was performed. Interventions: Patients were randomly assigned (2:1) to receive oral RGRN-305, 250-mg tablet, or matching placebo once daily for 16 weeks. Main Outcomes and Measures: The primary efficacy end point was the percentage of patients achieving Hidradenitis Suppurativa Clinical Response 50 (HiSCR-50) at week 16. Secondary efficacy end points included HiSCR-75 or HiSCR-90, Hidradenitis Suppurativa Physician's Global Assessment, Dermatology Life Quality Index scores, and a pain numeric rating scale. Safety was assessed by adverse events, physical examinations, clinical laboratory measurements, and electrocardiograms. Results: A total of 15 patients were enrolled, completed the study, and were included in all analyses (10 [67%] female; median age, 29 [IQR, 23-41] years). The primary end point HiSCR-50 at week 16 was achieved by a higher percentage in the RGRN-305 group (60% [6 of 10]) than in the placebo group (20% [1 of 5]). Improvements were also observed across all secondary end points at week 16, including higher rates of the harder-to-reach HiSCR levels; 50% (5 of 10) achieved HiSCR-75 and 30% (3 of 10) achieved HiSCR-90, whereas none of the placebo-treated patients achieved HiSCR-75 or HiSCR-90. RGRN-305 was well tolerated, with no deaths or serious adverse events, and treatment-emergent adverse events were similarly frequent between the RGRN-305 and placebo groups. Conclusions and Relevance: The findings of this trial suggest that heat shock protein 90 inhibition by RGRN-305 offers a novel mechanism of action in treating hidradenitis suppurativa, warranting further evaluation in larger trials. Trial Registration: ClinicalTrials.gov Identifier: NCT05286567.

Maresin-1 protects against pulmonary arterial hypertension by improving mitochondrial homeostasis through ALXR/HSP90α axis.

AIMS: Pulmonary arterial hypertension (PAH) is a progressive and lethal disease characterized by continuous proliferation of pulmonary arterial smooth muscle cell (PASMCs) and increased pulmonary vascular remodeling. Maresin-1 (MaR1) is a member of pro-resolving lipid mediators and exhibits protective effects on various inflammation-related diseases. Here we aimed to study the role of MaR1 in the development and progression of PAH and to explore the underlying mechanisms. METHODS AND RESULTS: We evaluated the effect of MaR1 treatment on PAH in both monocrotaline (MCT)-induced rat and hypoxia+SU5416 (HySu)-induced mouse models of pulmonary hypertension (PH). Plasma samples were collected from patients with PAH and rodent PH models to examine MaR1 production. Specific shRNA adenovirus or inhibitors were used to block the function of MaR1 receptors. The data showed that MaR1 significantly prevented the development and blunted the progression of PH in rodents. Blockade of the function of MaR1 receptor ALXR, but not LGR6 or RORα, with BOC-2, abolished the protective effect of MaR1 against PAH development and reduced its therapeutic potential. Mechanistically, we demonstrated that the MaR1/ALXR axis suppressed hypoxia-induced PASMCs proliferation and alleviated pulmonary vascular remodeling by inhibiting mitochondrial accumulation of heat shock protein 90α (HSP90α) and restoring mitophagy. CONCLUSION: MaR1 protects against PAH by improving mitochondrial homeostasis through ALXR/HSP90α axis and represents a promising target for PAH prevention and treatment.

The Effects of Cannabinoid Agonist, Heat Shock Protein 90 and Nitric Oxide Synthase Inhibitors on Increasing IL-13 and IL-31 Levels in Chronic Pruritus.

BACKGROUND: Heat shock protein 90 (Hsp90) inhibitor and cannabinoid agonists ameliorate dry skin-induced chronic itch. We have recently reported that cannabinoids, hsp90 and nitric oxide (NO) are involved in dry skin-induced itch. Here, we investigated the contribution of the Th2 cell signaling pathway to the antipruritic effect of the hsp90 inhibitor 17-Alilamino-17-demethoxygeldanamycin (17-AAG), nitric oxide synthase (NOS) inhibitor Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME) and cannabinoid agonist WIN 55,212-2 on a dry skin-induced scratch. METHODS: Dry skin-induced chronic itching was created by topical application of AEW (acetone/diethyl ether/water). WIN 55,212-2 (1 mg/kg, i.p.), L-NAME (1 mg/kg, i.p.) and increasing doses of 17-AAG (1, 3 and 5 mg/kg,i.p.) were administered to Balb/c mice (for each group, n = 6). After these applications, skin tissues were taken from the nape region of all of the mice. Gene and protein expressions of IL-13 and IL-31 were evaluated in skin tissues by RT-PCR and immunohistochemistry, respectively. RESULTS: IL-13 and IL-31 mRNA expressions and immune positive cell counts were increased in the AEW applied groups. WIN 55,212-2 reduced both of the increased cytokines levels, while L-NAME decreased only the IL-13. 17-AAG dose-dependently reduced the increased cytokine levels. IL-13 and IL-31 levels significantly decreased following the co-administration of these agents. CONCLUSION: These results show that increased levels of IL-13 and IL-31 are associated with pruritus. Hsp90 inhibition and cannabinoid system activation may induce antipruritic effects through down-regulation of these cytokines.

The Effects of the Heat Shock Protein 90 Inhibitor 17-Allylamino-17-Demethoxygeldanamycin, Cannabinoid Agonist WIN 55,212-2, and Nitric Oxide Synthase Inhibitor Nω-Nitro-L-Arginine Methyl Ester Hydrochloride on the Serotonin and Dry Skin-Induced Itch.

INTRODUCTION: In many types of itch, the interaction between immune system cells, keratinocytes, and sensory nerves involved in the transmission of itch is quite complex. Especially for patients with chronic itching, current treatments are insufficient, and their quality of life deteriorates significantly. OBJECTIVE: In this study, we aimed to investigate the role of the heat shock protein 90 (Hsp90) inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG), cannabinoid agonist WIN 55,212-2, and nitric oxide (NO) synthase inhibitor Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME) in pruritus. METHODS: We created a serotonin (5-HT)-induced (50 µg/µL/mouse, i.d.) acute and acetone-ether-water (AEW)-induced chronic itching models. 17-AAG (1, 3, and 5 mg/kg, intraperitoneally [i.p.]), WIN 55,212-2 (1 mg/kg, i.p.), and L-NAME (1 mg/kg, i.p.) were applied to Balb/c mice. RESULTS: We found that 17-AAG suppressed the scratches of mice, depending on the dose. The itch behavior was reduced by WIN 55,212-2, but L-NAME showed no antipruritic effect at the administered dose. The combined application of these agents in both pruritus models showed synergism in terms of the antipruritic effect. Our results showed that NO did not play a role in the antipruritic effect of WIN 55,212-2 and 17-AAG. Increased plasma IgE levels with AEW treatment decreased with the administration of 17-AAG (5 mg/kg, i.p.) and WIN 55,212-2. CONCLUSION: These results demonstrate that Hsp90 may play a role in the peripheral pathway of pruritus, and cannabinoid agonists and Hsp90 inhibitors can be used together in the treatment of pruritus.

Heat Shock Proteins as the Druggable Targets in Leishmaniasis: Promises and Perils.

Leishmania, the causative agent of leishmaniasis, is an intracellular pathogen that thrives in the insect gut and mammalian macrophages to complete its life cycle. Apart from temperature difference (26 to 37°C), it encounters several harsh conditions, including oxidative stress, inflammatory reactions, and low pH. Heat shock proteins (HSPs) play essential roles in cell survival by strategically reprogramming cellular processes and signaling pathways. HSPs assist cells in multiple functions, including differentiation, adaptation, virulence, and persistence in the host cell. Due to cyclical epidemiological patterns, limited chemotherapeutic options, drug resistance, and the absence of a vaccine, control of leishmaniasis remains a far-fetched dream. The essential roles of HSPs in parasitic differentiation and virulence and increased expression in drug-resistant strains highlight their importance in combating the disease. In this review, we highlighted the diverse physiological importance of HSPs present in Leishmania, emphasizing their significance in disease pathogenesis. Subsequently, we assessed the potential of HSPs as a chemotherapeutic target and underlined the challenges associated with it. Furthermore, we have summarized a few ongoing drug discovery initiatives that need to be explored further to develop clinically successful chemotherapeutic agents in the future.

T cell receptor repertoire as a prognosis marker for heat shock protein peptide complex-96 vaccine trial against newly diagnosed glioblastoma.

Glioblastoma multiforme (GBM) is the most common primary malignant brain tumor in adults with a dismal prognosis. We previously reported that vaccination with heat shock protein peptide complex-96 (HSPPC-96) improves survival in patients with newly diagnosed GBM (NCT02122822). Especially for patients with a strong antitumor immune response after vaccination, a durable survival benefit can be achieved. Here, we conducted T cell receptor (TCR) sequencing to retrospectively examine the TCR repertoires of tumor-infiltrating lymphocytes in long-term survivors (LTS) and short-term survivors (STS). We found that LTS exhibit lower TCR repertoire diversity compared with STS, indicating the prevalence of dominant TCR clones in LTS tumors. Accordingly, the LTS group showed increased inter-patient similarity, especially among high-frequency TCR clones, implying some of these dominant clones are shared among LTS. Indeed, we discovered four TCR clones significantly enriched in the LTS group: the presence of these clones has predictive value for stratifying patients prior to vaccination. Together, these findings uncover a group of preexisting TCR clones shared in LTS that can be utilized as candidate biomarkers to select GBM patients most likely to durably respond to HSPPC-96 treatment.

Heat shock protein peptide complex-96 vaccination for newly diagnosed glioblastoma: a phase I, single-arm trial.

BACKGROUND: Heat shock protein peptide complex-96 (HSPPC-96) triggers adaptive and innate antitumor immune responses. The safety and efficacy of HSPPC-96 vaccination was examined in patients with newly diagnosed glioblastoma multiforme (GBM). METHODS: In this open-label, single-arm, phase I study, adult patients were vaccinated with HSPPC-96 in combination with the standard treatment for newly diagnosed GBM after surgical resection. Primary endpoints were frequency of adverse events and progression-free survival (PFS) at 6 months. Secondary endpoints included overall survival (OS), PFS, and tumor-specific immune response (TSIR). RESULTS: A total of 20 patients with newly diagnosed GBM were enrolled from September 2013 to February 2015. No grade 3 or 4 vaccine-related adverse events were noted. After a median follow-up of 42.3 months, PFS was 89.5% (95% CI, 66.9%-98.7%) at 6 months, median PFS was 11.0 months (95% CI, 8.2-13.8), and median OS was 31.4 months (95% CI, 14.9-47.9). TSIR was significantly increased by 2.3-fold (95% CI, 1.7-3.2) after vaccination. Median OS for patients with high TSIR after vaccination was >40.5 months (95% CI, incalculable) as compared with 14.6 months (95% CI, 7.0-22.2) for patients with low TSIR after vaccination (hazard ratio, 0.25; 95% CI, 0.071-0.90; P = 0.034). A multivariate Cox regression model revealed TSIR after vaccination as a primary independent predicator for survival. CONCLUSION: The HSPPC-96 vaccination, combined with the standard therapy, is a safe and effective strategy for treatment of newly diagnosed GBM patients. TSIR after vaccination would be a good indicator predicting the vaccine efficacy. TRIAL REGISTRATION: ClinicalTrials.gov NCT02122822. FUNDING: National Key Technology Research and Development Program of the Ministry of Science and Technology of China (2014BAI04B01, 2014BAI04B02), Beijing Natural Science Foundation (7164253), Beijing Talents Fund (2014000021469G257), and Shenzhen Science and Technology Innovation Committee (JSGG20170413151359491).

A Randomized Phase 2 Study of ADXS11-001 Listeria monocytogenes-Listeriolysin O Immunotherapy With or Without Cisplatin in Treatment of Advanced Cervical Cancer.

OBJECTIVES: A global unmet medical need exists for effective treatments for persistent, recurrent, or metastatic cervical cancer, as patients have a short life expectancy. Recently, immunotherapies have shown promising survival benefits for patients with advanced forms of cancer. Axalimogene filolisbac (ADXS11-001), a Listeria monocytogenes immunotherapy with a broad effect on the immune system, is under investigation for treatment of human papillomavirus-associated cancers including cervical cancer. METHODS: This phase 2 study evaluated the safety and efficacy of ADXS11-001, administered with or without cisplatin, in patients with recurrent/refractory cervical cancer following prior chemotherapy and/or radiotherapy. A total of 109 patients were treated, and 69 were evaluable for tumor response at equal to or more than 3 months postbaseline. RESULTS: Median overall survival (OS) was comparable between treatment groups (ADXS11-001: 8.28 months; 95% confidence interval [CI], 5.85-10.5 months; ADXS11-001 + cisplatin: 8.78 months; 95% CI, 7.4-13.3 months). The 12- and 18-month milestone OS rates were 30.9% versus 38.9%, and 23.6% versus 25.9% for each group, respectively (34.9% and 24.8% combined). Median progression-free survival (6.10 vs 6.08 months) and the overall response rate (17.1% vs 14.7%) were similar for both groups. ADXS11-001 was generally well tolerated; adverse events were predominantly mild to moderate in severity and not related to treatment. More adverse events were reported in the combination group (429 vs 275). CONCLUSIONS: These promising safety and efficacy results, including the encouraging 12-month 34.9% combined OS rate, warrant further investigation of ADXS11-001 for treatment of recurrent/refractory cervical cancer.

Purification, characterization and safety assessment of the introduced cold shock protein B in DroughtGard maize.

DroughtGard maize was developed through constitutive expression of cold shock protein B (CSPB) from Bacillus subtilis to improve performance of maize (Zea mays) under water-limited conditions. B. subtilis commonly occurs in fermented foods and CSPB has a history of safe use. Safety studies were performed to further evaluate safety of CSPB introduced into maize. CSPB was compared to proteins found in current allergen and protein toxin databases and there are no sequence similarities between CSPB and known allergens or toxins. In order to validate the use of Escherichia coli-derived CSPB in other safety studies, physicochemical and functional characterization confirmed that the CSPB produced by DroughtGard possesses comparable molecular weight, immunoreactivity, and functional activity to CSPB produced from E. coli and that neither is glycosylated. CSPB was completely digested with sequential exposure to pepsin and pancreatin for 2 min and 30 s, respectively, suggesting that CSPB will be degraded in the mammalian digestive tract and would not be expected to be allergenic. Mice orally dosed with CSPB at 2160 mg/kg, followed by analysis of body weight gains, food consumption and clinical observations, showed no discernible adverse effects. This comprehensive safety assessment indicated that the CSPB protein from DroughtGard is safe for food and feed consumption.

Bilberry anthocyanins neutralize the cytotoxicity of co-chaperonin GroES fibrillation intermediates.

The co-chaperonin GroES (Hsp10) works with chaperonin GroEL (Hsp60) to facilitate the folding reactions of various substrate proteins. Upon forming a specific disordered state in guanidine hydrochloride, GroES is able to self-assemble into amyloid fibrils similar to those observed in various neurodegenerative diseases. GroES therefore is a suitable model system to understand the mechanism of amyloid fibril formation. Here, we determined the cytotoxicity of intermediate GroES species formed during fibrillation. We found that neuronal cell death was provoked by soluble intermediate aggregates of GroES, rather than mature fibrils. The data suggest that amyloid fibril formation and its associated toxicity toward cell might be an inherent property of proteins irrespective of their correlation with specific diseases. Furthermore, with the presence of anthocyanins that are abundant in bilberry, we could inhibit both fibril formation and the toxicity of intermediates. Addition of bilberry anthocyanins dissolved the toxic intermediates and fibrils, and the toxicity of the intermediates was thus neutralized. Our results suggest that anthocyanins may display a general and potent inhibitory effect on the amyloid fibril formation of various conformational disease-causing proteins.

HSPPC-96 vaccine in metastatic melanoma patients: from the state of the art to a possible future.

Heat-shock proteins are highly conserved, stress-induced proteins with chaperone function for trafficking and delivering peptides within the different compartments of the cell. Tumor-derived heat-shock protein-peptide complexes (HSPPCs) can be used for vaccination against malignancies. In particular, the HSPPC-96-based vaccine vitespen (formerly Oncophage) is the first autologous cancer vaccine made from individual patients' tumors that has shown encouraging results in clinical trials. In Phase I and II clinical trials, this vaccine has shown activity on different malignancies, such as gastric cancer, colorectal cancer, pancreatic cancer, non-Hodgkin's lymphoma and chronic myelogenous leukemia. In Phase III clinical trials in melanoma and kidney cancer, it demonstrated an excellent safety profile with almost no toxicity. Heat-shock protein-based vaccines can be considered as a novel therapeutic approach with a promising role in cancer management.

An adjuvant autologous therapeutic vaccine (HSPPC-96; vitespen) versus observation alone for patients at high risk of recurrence after nephrectomy for renal cell carcinoma: a multicentre, open-label, randomised phase III trial.

BACKGROUND: Treatment of localised renal cell carcinoma consists of partial or radical nephrectomy. A substantial proportion of patients are at risk for recurrence because no effective adjuvant therapy exists. We investigated the use of an autologous, tumour-derived heat-shock protein (glycoprotein 96)-peptide complex (HSPPC-96; vitespen) as adjuvant treatment in patients at high risk of recurrence after resection of locally advanced renal cell carcinoma. METHODS: In this open-label trial, patients were randomly assigned to receive either vitespen (n=409) or observation alone (n=409) after nephrectomy. Randomisation was done in a one to one ratio by a computer-generated pseudo-random number generator, with a block size of four, and was stratified by performance score, lymph node status, and nuclear grade. Vitespen was given intradermally once a week for 4 weeks, then every 2 weeks until vaccine depletion. The primary endpoint was recurrence-free survival. The final analysis of recurrence-free survival was planned to take place after 214 or more events of disease recurrence or deaths before recurrence had occurred. Analysis was by intention to treat (ITT). This study is registered with ClinicalTrials.gov, number NCT00033904. FINDINGS: 48 patients in the vitespen group and 42 in the observation group were excluded from the ITT population because they did not meet post-surgery inclusion criteria; the ITT population thus consisted of 361 patients in the vitespen group and 367 in the observation group. Final analysis of recurrence-free survival was triggered in November, 2005. Re-review of all patients in the ITT population by the clinical events committee identified 149 actual recurrences (73 in the vitespen group and 76 in the observation group), nine deaths before recurrence (two in the vitespen group and seven in the observation group), and 124 patients with baseline metastatic or residual disease (61 in the vitespen group and 63 in the observation group). Thus, after a median follow-up of 1.9 years (IQR 0.9-2.5) in the ITT population, recurrence events were reported in 136 (37.7%) patients in the vitespen group and 146 (39.8%) in the observation group (hazard ratio 0.923, 95% CI 0.729-1.169; p=0.506). After continued follow-up until March, 2007, there had been 70 deaths in the vitespen group and 72 in the observation group (p=0.896); however, overall survival data were not mature, and patients continue to be followed up for survival. In predefined exploratory analyses by AJCC stage, recurrence events in patients with stage I or II disease were reported in 19 (15.2%) patients in the vitespen group and 31 (27.0%) in the observation group (hazard ratio 0.576, 95% CI 0.324-1.023; p=0.056). The most commonly reported adverse events in the vitespen group were injection-site erythema (n=158) and injection-site induration (n=153). One serious adverse event-autoimmune thyroiditis of grade 2 severity-was reported in the vitespen group; no treatment-related grade 3 or 4 adverse events were reported. INTERPRETATION: No difference in recurrence-free survival was seen between patients given vitespen and those who received no treatment after nephrectomy for renal cell carcinoma. A possible improvement in recurrence-free survival in patients with early stage disease who received vitespen will require further validation.

Cancer vaccine--Antigenics.

Antigenics is developing a therapeutic cancer vaccine based on heat-shock proteins (HSPs). The vaccine [HSPPC-96, Oncophage] is in a pivotal phase III clinical trial for renal cancer at 80 clinical sites worldwide. The trial is enrolling at least 500 patients who are randomised to receive surgical removal of the primary tumour followed by out-patient treatment with Oncophage((R)) or surgery only. This study was initiated on the basis of results from a pilot phase I/II study and preliminary results from a phase II study in patients with renal cell cancer. In October 2001, Oncophage was designated as a fast-track product by the Food and Drug Administration in the US for the treatment of renal cell carcinoma. Oncophage is in phase I/II trials in Italy for colorectal cancer (30 patients) and melanoma. The trials in Italy are being conducted at the Istituto dei Tumouri, Milan (in association with Sigma-Tau). Preliminary data from the phase II trial for melanoma was presented at the AACR-NCI-EORTC International Conference in Florida, USA, in October 2001. Oncophage is also in a phase I/II (42 patients) and a phase II trial (84 patients) in the US for renal cell cancer, a phase II trial in the US for non-Hodgkin's lymphoma (35 patients), a phase II trial in the US for sarcoma (20-35 patients), a phase I/II trial in the US for melanoma (36 patients), and phase I/II trials in Germany for gastric (30 patients) and pancreatic cancers. A pilot phase I trial in patients with pancreatic cancer began in the US in 1997 with 5 patients enrolled. In November 2000, Antigenics announced that this trial had been expanded to a phase I/II study which would now include survival as an endpoint and would enroll 5 additional patients. The US trials are being performed at Memorial Sloan-Kettering Cancer Center and the M.D. Anderson Cancer Center. The trials in Germany are being carried out at Johannes Gutenberg-University Hospital, Mainz. Oncophage is an autologous vaccine consisting of purified complexes of tumour-derived HSPs linked to tumour antigen peptides. When these HSPPC are readministered to a patient following surgery or biopsy of the tumour, the antigenic tumour peptides are expressed on the surface of potent antigen-presenting cells of the immune system, such as macrophages and dendritic cells. This stimulates a much more powerful anti-tumour immune response than that generated by expression of the same antigens by the tumour cell. Thus, Antigenics autologous HSP technology is attractive because it is highly specific for individual patients and circumvents the need for identification of specific antigens for individual cancers (i.e. it does not require definition of the antigenic epitopes on cancer cells) and it overcomes the immune tolerance associated with various tumours. Oncophage is manufactured in a 10-hour process from surgically resected autologous tumour. A minimum of 1-3g of tumour tissue is required to produce enough Oncophage for a course of treatment. The major limiting factor for producing Oncophage from a particular cancer is the ability to purify HSP from that cancer. From clinical studies to date, Antigenics has been able to produce HSP from 100, 98, 90, 71 and 30% of colorectal carcinoma, renal cell carcinoma, melanoma, gastric cancer and pancreatic cancer tumours, respectively. The low success rate with pancreatic cancers is because of the high concentration of proteases in that tissue type. HSPs are a family of highly conserved proteins present in the cells of all organisms. They function as molecular chaperones, assisting the correct folding of polypeptides and aiding intracellular protein transport. In addition, HSPs associate with a broad range of peptides derived from intracellular protein degradation, including antigenic peptides produced in tumour cells. Antigenics has exclusively licensed worldwide rights to its HSP immunotherapeutic complexes from Mount Sinai School of Medicine and Fordham University in the USA. On 3 November 1998, Antigenics was issued a US patent (5,830,464) covering immunotherapy in which antigen-presenting cells are isolated and mixed with heat shock protein-antigen complexes purified from patients' tumours. The patent was issued to Fordham University, New York, US, who subsequently licensed it to Antigenics. Antigenics has an agreement with Sigma Tau, under the terms of which the latter company will fund 2 clinical trials in return for an option to market Oncophage in Italy, Portugal, Spain and Switzerland. Antigenics also has an agreement with Medison for marketing of Oncophage in Israel.

Effect of intrathymic administration of mycobacterial heat shock protein 65 and peptide p277 on the development of diabetes in NOD mice: caution required in vaccination studies.

Heat shock protein 65 (hsp65) and a derived peptide, p277, are autoantigens reported in IDDM. I.p. injection of hsp65 reduced diabetes incidence in NOD mice and administration of p277 cured already diabetic mice. Also, intrathymic (i.t.) administration of whole islets or GAD65 prevented diabetes in NOD mice. The aim of this study was to evaluate whether i.t. injection of mycobacterial hsp65 or p277 can prevent diabetes in NOD mice. Three-week-old NOD female mice were injected intrathymically with 50 microg of hsp65 (n=30), 5 microg of p277 (n=30), and PBS (n=29). Diabetes incidence was observed for the following 300 days. Pancreas was then used for histological and immunohistological evaluation. No significant differences in diabetes incidence were observed among the three groups of mice. Interestingly, hsp65-treated mice developed diabetes slightly faster at 177+/-6 days compared to 202+/-8 days (p=0.015) for the p277-treated group and 197+/-7 days (p=0.033) for controls. The insulitis score and average islet size did not differ significantly among the three groups of diabetic mice. Scattered TCR-gamma/delta positive cells were found in the pancreas of all groups of mice. In contrast, a huge infiltrate of TCR-gamma/delta positive cells was detected in four out of eight (50%) p277-diabetic NOD mice. Thus, our data show an earlier onset of diabetes in hsp65-treated mice and no improvement in the incidence with either hsp65 or p277, suggesting that hsp65 acts in a different way from what was reported with GAD65. Caution is advised in future vaccination studies as hsp65 poses a potential danger.