Formulation of HBsAg in Montanide ISA 51VG adjuvant: Immunogenicity study and monitoring long-lived humoral immune responses

Montanide ISA 51VG adjuvant has been approved for human clinical application and stimulates cellular and humoral immune responses. Here, HBsAg was formulated in Montanide ISA51VG adjuvant to compare its potency with the Fendrix and HBsAg-alum vaccines. In particular, the long-term humoral response was assessed up to 220 days after the final immunization. BALB/c mice were allocated into six groups. Treatment groups were injected with HBsAg-Montanide ISA51VG, the Fendrix and commercial HBsAg-alum, respectively. Montanide ISA51 VG, Alum and PBS injected mice were considered as control groups. Mice were immunized three times with 2-week intervals on days 0, 14 and 28 by subcutaneous injection. Lymphocyte proliferation was assessed with the BrdU method. IFN-γ, IL-2 and IL-4 cytokines, specific total IgG and IgG1/IgG2a isotypes were assessed using ELISA. The HBsAg-Montanide ISA51VG vaccine resulted in a significant increase in lymphocyte proliferation versus HBsAg-alum and higher IL-2 cytokine production versus the Fendrix. Comparable IL-4 and IFN-γ cytokines responses were observed for these vaccines. Following the first immunization, IgG increased more in HBs-Montanide 51VG group versus the HBs-alum group, while after the second and third shots comparable responses were observed in comparison to the HBs-alum group. Monitoring for 220 days after the final vaccination showed the superiority of HBsAg-Montanide ISA 51VG vaccine versus HBsAg-alum and even the Fendrix vaccine in the induction of long-term antibody responses. This study suggests that HBsAg-Montanide ISA51VG as a novel vaccine formulation can trigger both cellular and long-lasting humoral immune responses more efficiently than conventional HBsAg vaccines.

Raising antibodies against epoxyscillirosidine, the toxic principle contained in Moraea pallida Bak. (Iridaceae), in rabbits

Moraea pallida Bak. (yellow tulp) poisoning is the most important plant cardiac glycoside toxicosis in South Africa. The toxic principle, a bufadienolide, is 1α, 2α-epoxyscillirosidine. The aim was to investigate the potential to develop a vaccine against epoxyscillirosidine. Epoxyscillirosidine, proscillaridin and bufalin, were successfully conjugated to hen ovalbumin (OVA), bovine serum albumin (BSA) and keyhole limpet haemocyanin (KLH). There was a low immune response following vaccination of adult male New Zealand White rabbits with epoxyscillirosidine-OVA (n = 3) and OVA (n = 3) using Freund's adjuvant in Trial (T) 1. The immune response improved significantly in T2 following doubling of the dose to 0.8 mg/rabbit and changing the adjuvant to Montanide. In T3, the rabbits (n = 15), allocated into 5 equal groups, vaccinated with proscillaridin-BSA, bufalin-BSA, epoxyscillirosidine-KLH, epoxyscillirosidine-BSA and BSA respectively, using Montanide adjuvant, developed antibodies against the administered immunogens, with epoxyscillirosidine-KLH inducing the highest immune response. Proscillaridin and bufalin antibodies cross-reacted with epoxyscillirosidine in an enzyme linked immunosorbent assay. The conjugation methodology will be adjusted in the future to target optimal conjugation efficiency. Additional vaccination will be conducted in search of neutralizing antibodies against the yellow tulp toxin. The cross-reactivity of proscillaridin and bufalin antibodies with epoxyscillirosidine could be studied in future to explore the potential to prevent yellow tulp poisoning.

The fatty acid oleate is required for innate immune activation and pathogen defense in Caenorhabditis elegans

Fatty acids affect a number of physiological processes, in addition to forming the building blocks of membranes and body fat stores. In this study, we uncover a role for the monounsaturated fatty acid oleate in the innate immune response of the nematode Caenorhabditis elegans. From an RNAi screen for regulators of innate immune defense genes, we identified the two stearoyl-coenzyme A desaturases that synthesize oleate in C. elegans. We show that the synthesis of oleate is necessary for the pathogen-mediated induction of immune defense genes. Accordingly, C. elegans deficient in oleate production are hypersusceptible to infection with diverse human pathogens, which can be rescued by the addition of exogenous oleate. However, oleate is not sufficient to drive protective immune activation. Together, these data add to the known health-promoting effects of monounsaturated fatty acids, and suggest an ancient link between nutrient stores, metabolism, and host susceptibility to bacterial infection.

The evolution of multicellular organisms has been shaped by their interactions with pathogenic microorganisms. The microscopic nematode C. elegans eats bacteria for food and has evolved inducible immune defenses toward ingested pathogens that are coordinated within intestinal epithelial cells. C. elegans, therefore, presents a genetic system to characterize the requirements for the activation of innate immune defenses. Here, we show that the monounsaturated fatty acid oleate is necessary for the induction of innate immune defenses and for protection against bacterial pathogens, which defines a new link between metabolism and the regulation of anti-pathogen responses in a metazoan host.

Topical electrophilic nitro-fatty acids potentiate cutaneous inflammation

Endogenous electrophilic fatty acids mediate anti-inflammatory responses by modulating metabolic and inflammatory signal transduction and gene expression. Nitro-fatty acids and other electrophilic fatty acids may thus be useful for the prevention and treatment of immune-mediated diseases, including inflammatory skin disorders. In this regard, subcutaneous (SC) injections of nitro oleic acid (OA-NO₂), an exemplary nitro-fatty acid, inhibit skin inflammation in a model of allergic contact dermatitis (ACD). Given the nitration of unsaturated fatty acids during metabolic and inflammatory processes and the growing use of fatty acids in topical formulations, we sought to further study the effect of nitro-fatty acids on cutaneous inflammation. To accomplish this, the effect of topically applied OA-NO₂ on skin inflammation was evaluated using established murine models of contact hypersensitivity (CHS). In contrast to the effects of subcutaneously injected OA-NO₂, topical OA-NO₂ potentiated hapten-dependent inflammation inducing a sustained neutrophil-dependent inflammatory response characterized by psoriasiform histological features, increased angiogenesis, and an inflammatory infiltrate that included neutrophils, inflammatory monocytes, and γδ T cells. Consistent with these results, HPLC-MS/MS analysis of skin from psoriasis patients displayed a 56% increase in nitro-conjugated linoleic acid (CLA-NO₂) levels in lesional skin compared to non-lesional skin. These results suggest that nitro-fatty acids in the skin microenvironment are products of cutaneous inflammatory responses and, in high local concentrations, may exacerbate inflammatory skin diseases.

A multi-peptide, dual-adjuvant telomerase vaccine (GX301) is highly immunogenic in patients with prostate and renal cancer

BACKGROUND

Anti-tumor vaccination is a new frontier in cancer treatment applicable to immunogenic neoplasms such as prostate and renal cancers. GX301 is a vaccine constituted by four telomerase peptides and two adjuvants, Montanide ISA-51 and Imiquimod.

OBJECTIVE

The aim of this study was to analyze safety and tolerability of GX301 in an open-label, phase I/II trial. Immunological and clinical responses were also evaluated as secondary endpoints.

EXPERIMENTAL DESIGN

GX301 was administered by intradermally injecting 500 μg of each peptide (dissolved in Montanide ISA-51) in the skin of the abdomen. Imiquimod was applied as a cream at the injection sites. The protocol included 8 administrations at days 1, 3, 5, 7, 14, 21, 35, 63. Eligible patients were affected with stage IV prostate or renal cancer resistant to conventional treatments. Patients were clinically and immunologically monitored up to 6 months from the first immunization.

RESULTS

No grade 3-4 adverse events were observed. Evidence of vaccine-specific immunological responses was detected in 100 % of patients. Disease stabilization occurred in 4 patients. Prolonged progression-free survival and overall survival were observed in patients showing a full pattern of vaccine-specific immunological responses.

CONCLUSION

GX301 demonstrated to be safe and highly immunogenic. Further studies are needed to determine its clinical efficacy.

Effects on immunogenicity by formulations of emulsion-based adjuvants for malaria vaccines

New malaria vaccines are urgently needed to improve vaccine protective efficacy. PfCelTOS is a recombinant malaria vaccine antigen that has shown protective efficacy in a small-animal challenge model when combined with a water-in-oil emulsion adjuvant (Montanide ISA 720). In this report, we show that PfCelTOS vaccines containing GLA-SE (a stable oil-in-water emulsion combined with a Toll-like receptor 4 [TLR4] agonist) elicit strong Th1-type immune responses in BALB/c mice. These responses include higher antigen-specific IgG2a antibody titers and more gamma interferon (IFN-γ) production than those seen with a PfCelTOS vaccine containing Montanide ISA 720. Furthermore, reducing the emulsion dose from 2% to 1% or 0.5% (vol/vol) squalene in GLA-SE did not compromise immunogenicity. Emulsion dose titration in the absence of formulated GLA caused some reduction in humoral and cellular immune responses compared to those with the 2% squalene emulsion dose.

Phase I trial of Wilms' Tumor 1 (WT1) peptide vaccine with GM-CSF or CpG in patients with solid malignancy

BACKGROUND

The aim of this study was to investigate the safety and efficacy of combinatorial use of granulocyte-macrophage colony-stimulating factor (GM-CSF) and CpG oligodeoxynucleotides (CpG-ODN) as immunoenhancement adjuvants in Wilms' Tumor 1 (WT1) vaccine therapy for patients with solid malignancy.

PATIENTS AND METHODS

The patients were placed into treatment groups as follows: WT1 peptide alone, WT1 peptide with GM-CSF (100 μg) and WT1 peptide with CpG-ODN (100 μg). HLA-A *2402 or *0201/*0206-restricted, WT1 peptide emulsified with Montanide ISA51 was injected intradermally every week for eight weeks. Toxicities were evaluated according to the National Cancer Institute Common Terminology Criteria for Adverse Events ver. 3.0. Tumor size, which was measured by computed tomography, was determined every four weeks. The responses were analyzed according to Response Evaluation Criteria in Solid Tumors.

RESULTS

The protocol was well tolerated; only local erythema occurred at the WT1 vaccine injection site. The disease control rate of the groups treated with WT1 peptide alone (n=10), with combinatorial use of GM-CSF (n=8) and with combinatorial use of CpG-ODN (n=10), in the initial two months was 20%, 25% and 60%, respectively.

CONCLUSION

Addition of GM-CSF or CpG-ODN to the WT1 peptide vaccine for patients with solid malignancy was safe and improved the effectiveness of clinical response.

Unique interplay between sugar and lipid in determining the antigenic potency of bacterial antigens for NKT cells

Structural and biophysical studies reveal the induced-fit mechanism underlying the stringent specificity of invariant natural killer T cells for unique glycolipid antigens from the pathogen Streptococcus pneumoniae.

Invariant natural killer T (iNKT) cells are an evolutionary conserved T cell population characterized by features of both the innate and adaptive immune response. Studies have shown that iNKT cells are required for protective responses to Gram-positive pathogens such as Streptococcus pneumoniae, and that these cells recognize bacterial diacylglycerol antigens presented by CD1d, a non-classical antigen-presenting molecule. The combination of a lipid backbone containing an unusual fatty acid, vaccenic acid, as well as a glucose sugar that is weaker or not stimulatory when linked to other lipids, is required for iNKT cell stimulation by these antigens. Here we have carried out structural and biophysical studies that illuminate the reasons for the stringent requirement for this unique combination. The data indicate that vaccenic acid bound to the CD1d groove orients the protruding glucose sugar for TCR recognition, and it allows for an additional hydrogen bond of the glucose with CD1d when in complex with the TCR. Furthermore, TCR binding causes an induced fit in both the sugar and CD1d, and we have identified the CD1d amino acids important for iNKT TCR recognition and the stability of the ternary complex. The studies show also how hydrogen bonds formed by the glucose sugar can account for the distinct binding kinetics of the TCR for this CD1d-glycolipid complex. Therefore, our studies illuminate the mechanism of glycolipid recognition for antigens from important pathogens.

Invariant natural killer T (iNKT) cells are an evolutionarily conserved population of immune cells that recognize lipid antigens. A protein called a T cell receptor for antigen (TCR) on the surface of these iNKT cells recognizes lipids bound to a protein called CD1d on the surface of antigen-presenting cells. Here we describe the three-dimensional structure of the complex that forms between CD1d and the iNKT TCR together with a glycolipid antigen from the infectious bacterium Streptococcus pneumoniae, which is a common cause of bacterial meningitis in adults and is responsible for many other pneumococcal infections. We determined the three-dimensional structure of the complex by X-ray crystallography. The data obtained allow us to understand the structural requirements that make this glycolipid a potent antigen for iNKT cells, and why the TCR of these cells recognizes a particular combination of hexose sugar and diacylglycerol lipid. Moreover, by mutating CD1d and using biophysical methods to study the mutant protein complexes, we analyzed the role of the protein–protein interface between CD1d and the TCR and found that it plays an important role in the stability, but not the formation, of the trimolecular complex containing glycolipid antigen.

A single injection of 19 kda carboxy-terminal fragment of Plasmodium yoelii merozoite surface protein 1 (PyMSP1(19)) formulated with Montanide ISA and CpG ODN induces protective immune response in mice

OBJECTIVE

To investigate the efficacy of a vaccine formulation of the 19 kDa conserved carboxyl-terminal fragment of Plasmodium yoelii merozoite surface protein-1 (PyMSP1(19)) formulated with CpG ODN 1826 and Montanide ISA51 or ISA720 when used to immunize mice by a single injection.

METHODS

Groups of BALB/c mice were immunized parenterally with one, two or four injections with PBS or PyMSP1(19) formulated with CpG ODN in ISA51 or ISA720. Sera were collected weekly and assessed for total IgG and IgG subclass titers. Protection was tested by challenge infection with P. yoelii YM.

RESULTS

Interestingly, single injection immunization showed the same kinetics of antibody responses as two- or four-injection immunization. However, the peak antibody response induced by PyMSP1(19) in CpG ODN and ISA51 appeared earlier than that induced by PyMSP1(19) in CpG ODN and ISA720 (28 days vs 41 days). At day 63 after the first injection, the PyMSP1(19)-specific IgG antibody levels by single injection and four-injection immunizations were not different. However, the levels of the IgG2a antibody subclass were significantly lower by single injection immunization with PyMSP1(19) in CpG ODN and ISA720. The antibodies were sustained at high levels for at least 20 weeks. After challenge infection, all mice immunized by a single injection of PyMSP1(19) in CpG ODN and ISA51 survived with low-grade parasitemia, while 50% of mice immunized with PyMSP1(19) in CpG ODN and ISA720 died with high levels of parasitemia.

CONCLUSION

These findings suggest that MSP1(19) immunization by a single injection can induce protective immunity, particularly when formulated with an appropriate strong adjuvant.

A phase I study of vaccination with NY-ESO-1f peptide mixed with Picibanil OK-432 and Montanide ISA-51 in patients with cancers expressing the NY-ESO-1 antigen

We conducted a phase I clinical trial of a cancer vaccine using a 20-mer NY-ESO-1f peptide (NY-ESO-1 91-110) that includes multiple epitopes recognized by antibodies, and CD4 and CD8 T cells. Ten patients were immunized with 600 μg of NY-ESO-1f peptide mixed with 0.2 KE Picibanil OK-432 and 1.25 ml Montanide ISA-51. Primary end points of the study were safety and immune response. Subcutaneous injection of the NY-ESO-1f peptide vaccine was well tolerated. Vaccine-related adverse events observed were fever (Grade 1), injection-site reaction (Grade 1 or 2) and induration (Grade 2). Vaccination with the NY-ESO-1f peptide resulted in an increase or induction of NY-ESO-1 antibody responses in nine of ten patients. The sera reacted with recombinant NY-ESO-1 whole protein as well as the NY-ESO-1f peptide. An increase in CD4 and CD8 T cell responses was observed in nine of ten patients. Vaccine-induced CD4 and CD8 T cells responded to NY-ESO-1 91-108 in all patients with various HLA types with a less frequent response to neighboring peptides. The findings indicate that the 20-mer NY-ESO-1f peptide includes multiple epitopes recognized by CD4 and CD8 T cells with distinct specificity. Of ten patients, two with lung cancer and one with esophageal cancer showed stable disease. Our study shows that the NY-ESO-1f peptide vaccine was well tolerated and elicited humoral, CD4 and CD8 T cell responses in immunized patients.

Immunogenicity in rhesus of the Plasmodium vivax mosquito stage antigen Pvs25H with Alhydrogel and Montanide ISA 720

Pvs25 is an ookinete surface protein from Plasmodium vivax that is the target of transmission-blocking antibodies. Two immunogenicity trials in rhesus monkeys with a recombinant form of the protein, Pvs25H, were undertaken. Monkeys were vaccinated with Pvs25H adsorbed to Alhydrogel or emulsified in Montanide ISA 720 at 0, 4 and 27 weeks (study 1) or in Montanide ISA 720 at 0 and 18 weeks (study 2) with 1.5 or 15 microg Pvs25H in 0.1 or 0.5 mL of emulsion (four combinations). Immunogenicity was assessed by ELISA and by membrane-feeding experiments using P. vivax-infected blood from human volunteers (studies 1 and 2) or from chimpanzees (study 1). Both vaccine trials generated antibodies that blocked transmission of P. vivax to mosquitoes. Antibody titres and transmission blocking were higher with Montanide ISA 720 than with Alhydrogel in the first trial and with the 15 microg Pvs25H/0.5 mL ISA 720 combination in the second trial.

Vaccination with NY-ESO-1 protein and CpG in Montanide induces integrated antibody/Th1 responses and CD8 T cells through cross-priming

The use of recombinant tumor antigen proteins is a realistic approach for the development of generic cancer vaccines, but the potential of this type of vaccines to induce specific CD8(+) T cell responses, through in vivo cross-priming, has remained unclear. In this article, we report that repeated vaccination of cancer patients with recombinant NY-ESO-1 protein, Montanide ISA-51, and CpG ODN 7909, a potent stimulator of B cells and T helper type 1 (Th1)-type immunity, resulted in the early induction of specific integrated CD4(+) Th cells and antibody responses in most vaccinated patients, followed by the development of later CD8(+) T cell responses in a fraction of them. The correlation between antibody and T cell responses, together with the ability of vaccine-induced antibodies to promote in vitro cross-presentation of NY-ESO-1 by dendritic cells to vaccine-induced CD8(+) T cells, indicated that elicitation of NY-ESO-1-specific CD8(+) T cell responses by cross-priming in vivo was associated with the induction of adequate levels of specific antibodies. Together, our data provide clear evidence of in vivo cross-priming of specific cytotoxic T lymphocytes by a recombinant tumor antigen vaccine, underline the importance of specific antibody induction for the cross-priming to occur, and support the use of this type of formulation for the further development of efficient cancer vaccines.

Long-lasting protective immune response to the 19-kilodalton carboxy-terminal fragment of Plasmodium yoelii merozoite surface protein 1 in mice

Merozoite surface protein 1 (MSP1) is the major protein on the surface of the plasmodial merozoite, and its carboxy terminus, the 19-kDa fragment (MSP1(19)), is highly conserved and effective in induction of a protective immune response against malaria parasite infection in mice and monkeys. However, the duration of the immune response has not been elucidated. As such, we immunized BALB/c mice with a standard four-dose injection of recombinant Plasmodium yoelii MSP1(19) formulated with Montanide ISA51 and CpG oligodeoxynucleotide (ODN) and monitored the MSP1(19)-specific antibody levels for up to 12 months. The antibody titers persisted constantly over the period of time without significant waning, in contrast to the antibody levels induced by immunization with Freund's adjuvant, where the antibody levels gradually declined to significantly lower levels 12 months after immunization. Investigation of immunoglobulin G (IgG) subclass longevity revealed that only the IgG1 antibody level (Th2 type-driven response) decreased significantly by 6 months, while the IgG2a antibody level (Th1 type-driven response) did not change over the 12 months after immunization, but the boosting effect was seen in the IgG1 antibody responses but not in the IgG2a antibody responses. After challenge infection, all immunized mice survived with negligibly patent parasitemia. These findings suggest that protective immune responses to MSP1(19) following immunization using oil-based Montanide ISA51 and CpG ODN as an adjuvant are very long-lasting and encourage clinical trials for malaria vaccine development.

Modifications increasing the efficacy of recombinant vaccines; marked increase in antibody titers with moderately repetitive variants of a therapeutic allergy vaccine

Development of vaccines targeting important self-molecules like tumor antigens, IgE, cytokines or other regulatory molecules, brings about challenges that are not met in classical vaccine development. Tolerance inducing mechanisms reduce the levels of therapeutic antibodies in the vaccinated subject, and anti-self antibody titers are frequently more than 50-fold lower than the anti-non-self response to the carrier. In order to overcome this limitation in efficacy we have explored various methods to enhance the immunogenicity of the vaccine antigen. Vaccination with a molecule containing two IgE Cepsilon3 domains and thereby a low level of repetitiveness markedly increased the efficacy. The anti-IgE antibody titers in the animals treated with the dimeric vaccine antigen were 4.5, 5 and 8 times higher than in the animals treated with the monomer, in three independent experiments. In addition, this increase in efficacy was not masked by the use of potent adjuvants. The effect persisted even in the presence of Freunds or Montanide ISA 51, two mineral oil based adjuvants. This in contrast to most Toll-like receptor (TLR) agonists, which appear to enhance the immune response only when administrated together with weak adjuvants. This clearly shows that the introduction of a moderately repetitive structure is enough to substantially increase the efficacy of a therapeutic vaccine.

Toll-like receptor agonists influence the magnitude and quality of memory T cell responses after prime-boost immunization in nonhuman primates

There is a remarkable heterogeneity in the functional profile (quality) of T cell responses. Importantly, the magnitude and/or quality of a response required for protection may be different depending on the infection. Here, we assessed the capacity of different Toll like receptor (TLR)-binding compounds to influence T helper cell (Th)1 and CD8⁺ T cell responses when used as adjuvants in nonhuman primates (NHP) with HIV Gag as a model antigen. NHP were immunized with HIV Gag protein emulsified in Montanide ISA 51, an oil-based adjuvant, with or without a TLR7/8 agonist, a TLR8 agonist, or the TLR9 ligand cytosine phosphate guanosine oligodeoxynucleotides (CpG ODN), and boosted 12 wk later with a replication-defective adenovirus-expressing HIV-Gag (rAD-Gag). Animals vaccinated with HIV Gag protein/Montanide and CpG ODN or the TLR7/8 agonist had higher frequencies of Th1 responses after primary immunization compared to all other vaccine groups. Although the rAD-Gag boost did not elevate the frequency of Th1 memory cytokine responses, there was a striking increase in HIV Gag-specific CD8⁺ T cell responses after the boost in all animals that had received a primary immunization with any of the TLR adjuvants. Importantly, the presence and type of TLR adjuvant used during primary immunization conferred stability and dramatically influenced the magnitude and quality of the Th1 and CD8⁺ T cell responses after the rAD-Gag boost. These data provide insights for designing prime-boost immunization regimens to optimize Th1 and CD8⁺ T cell responses.

Induction of transmission-blocking immunity in Aotus monkeys by vaccination with a Plasmodium vivax clinical grade PVS25 recombinant protein

Aotus monkeys were used to determine the immunogenicity of Pvs25 protein expressed in the zygote/ookinete surface. Animals were immunized in three times with 100 microg of Pvs25 formulated in Montanide ISA-720. Antibodies to Pvs25 detected by an enzyme-linked immunosorbent assay appeared by day 30 after the first immunization, with a peak of antibodies levels on day 150. These antibodies were still detectable on day 300. Plasma samples on day 150 from experimental group were able to completely block the development of the parasite in Anopheles albimanus mosquitoes artificially fed with human isolates of Plasmodium vivax. Immunized Aotus monkeys were infected with blood forms of the P. vivax Salvador I strain and no boosting effect of blood infection on titers of antibodies to Pvs25 was observed despite the presence of infective gametocytes. In conclusion, Pvs25 protein formulated in Montanide ISA-720 induces efficient and long-lasting transmission-blocking antibodies that cannot be boosted by parasite infection.

Autoimmune Toxicities Associated with the Administration of Antitumor Vaccines and Low-Dose Interleukin-2

The purpose of this investigation was to evaluate the occurrence of autoimmune toxicities associated with the administration of low-dose IL-2 in conjunction with vaccines for melanoma. Ninety-three patients with stage IIB, III, or IV melanoma were enrolled in three clinical trials and received anti-melanoma vaccines on days 1, 8, 15, 29, 36, and 43. The vaccines comprised peptide-pulsed dendritic cells, autologous tumor cells with GM-CSF in Montanide ISA-51, or synthetic peptides with GM-CSF in Montanide ISA-51. In conjunction with the vaccines, all patients were administered 3 x 10(6) IU/m2/d IL-2 subcutaneously for 42 days, either days 8 to 49 or 29 to 70. Clinical and laboratory data from these studies were reviewed in aggregate to evaluate the occurrence of autoimmune toxicities. Of 91 evaluable patients, vitiligo was documented in 6 patients (7%). In addition, one patient experienced transient severe insulin-dependent diabetes that resolved after discontinuing IL-2, and another experienced an exacerbation of his pre-existing diabetes; these occurrences are consistent with an autoimmune insulitis. Four occurrences (4%) of transient minor ocular toxicity were documented, but no autoimmune ocular toxicities or changes in visual acuity were found. Of 55 evaluable patients, 14 experienced thyroid abnormalities (25%). These were attributed to an autoimmune thyroiditis, which was supported by findings of antithyroid antibodies in three of the seven patients evaluated. Overall, autoimmune toxicities affecting several organ systems were observed in patients receiving melanoma vaccines in conjunction with low-dose IL-2. None of these toxicities caused major long-term effects, though one was acutely life-threatening and others contributed to treatment-related morbidity. Peptide- or cell-based vaccines administered in combination with low-dose IL-2 appear to be capable of breaking tolerance to self-antigens; despite the associated toxicities, these combinations may still be useful to administer as an immunotherapy for cancer. However, careful monitoring for autoimmune toxicities should be incorporated in future clinical studies incorporating low-dose IL-2.

MAGE-A1-, MAGE-A10-, and gp100-derived peptides are immunogenic when combined with granulocyte-macrophage colony-stimulating factor and montanide ISA-51 adjuvant and administered as part of a multipeptide vaccine for melanoma

Twelve peptides derived from melanocyte differentiation proteins and cancer-testis Ags were combined and administered in a single mixture to patients with resected stage IIB, III, or IV melanoma. Five of the 12 peptides included in this mixture had not previously been evaluated for their immunogenicity in vivo following vaccination. We report in this study that at least three of these five peptides (MAGE-A1(96-104), MAGE-A10(254-262), and gp100(614-622)) are immunogenic when administered with GM-CSF in Montanide ISA-51 adjuvant. T cells secreting IFN-gamma in response to peptide-pulsed target cells were detected in peripheral blood and in the sentinel immunized node, the node draining a vaccine site, after three weekly injections. The magnitude of response typically reached a maximum after two vaccines, and though sometimes diminished thereafter, those responses typically were still detectable 6 wks after the last vaccines. Most importantly, tumor cell lines expressing the appropriate HLA-A restriction element and MAGE-A1, MAGE-A10, or gp100 proteins were lysed by corresponding CTL. This report supports the continued use of the MAGE-A1(96-104), MAGE-A10(254-262), and gp100(614-622) epitopes in peptide-based melanoma vaccines and thus expands the list of immunogenic peptide Ags available for human use. Cancer-testis Ags are expressed in multiple types of cancer; thus the MAGE-A1(96-104) and MAGE-A10(254-262) peptides may be considered for inclusion in vaccines against cancers of other histologic types, in addition to melanoma.

Montanide® ISA 720 vaccines: quality control of emulsions, stability of formulated antigens, and comparative immunogenicity of vaccine formulations

Montanide ISA 720 is an experimental adjuvant, formulated as water-in-oil emulsions, that induces high antibody titers in several animal species. It has been used in human vaccine trials with malaria and HIV vaccines. The heightened response is likely due, in part, to the formation of a depot at the injection site. However, post-formulation modifications were seen with seven proteins tested during storage of ISA 720 formulations at 37 degrees C for 1 week and two proteins stored longer at 4 degrees C. Potency studies in mice, in which the stored vaccines were diluted into placebo emulsions for appropriate dosing, indicated that this instability could lead to loss of immunogenicity in the post-injection depot, limiting the allowable storage time of preformed vaccines. We describe point-of-injection formulation for ISA 720 vaccines that meets the requirement for in vitro stability. For preformed vaccines, addition of glycine or glycylglycine prevented antigen modification on storage at 37 degrees C, providing a potential way of stabilizing antigen/ISA 720 formulations for in vitro storage and the post-injection depot.

Characterization of long-term effector-memory T-cell responses in patients with resected high-risk melanoma receiving a melanoma Peptide vaccine

The authors determined whether long-term memory T cells could be detected in patients who received a multipeptide vaccine for high-risk resected melanoma. Five HLA-A*0201 patients received a vaccine that included the gp100(209-217) (210M) peptide with Montanide ISA 51. Peripheral blood mononuclear cells were obtained before therapy, after 6 months of vaccinations, and from 18 months to 36 months later. The presence of gp100 antigen-specific cytolytic T cells was measured by ELISPOT, tetramer and chromium release assays. Tetramer-positive CD8 cells were phenotyped by flow cytometry for markers including CD44, CD45RA, and CCR7. T-cell avidity and its evolution over time were examined in selected patients. Epitope spreading was analyzed by assessment of gp100(280-288) (288V) T cells. All patients exhibited a significant increase in tetramer-positive gp100-specific CD8 T cells that decayed at different rates over 18 to 36 months after vaccinations. Cells from all patients exhibited an effector-memory phenotype and were generally CD45 RA low/CCR7 negative and CD44 positive. Tetramer-positive cells declined over time in four of the five patients, but the proportion of tetramer-positive CD8 cells that secreted gamma-interferon rose, suggesting enrichment for effector cells. Epitope spreading for the gp100(280-288) (288V) epitope was detected. One patient maintained a population of 2.5% circulating gp100 tetramer-positive cells over 36 months. Avidity analysis showed no changes over time after induction of antigen-specific T cells. Vaccination with a heteroclitic melanoma antigen peptide with Montanide ISA 51 generated populations of circulating functional effector-memory T cells that were specific for gp100 and long-lived in the circulation for periods of 18 to 36 months after vaccination.

Immune responses to orally administered PLGA microparticles: influence of oil vehicles and surfactive agents

Lipid vehicles and surfactive agents have been successfully used to increase oral absorption and availability of free and encapsulated proteins. In order to investigate if these vehicles could also enhance the serum IgG responses elicited after the oral administration of protein antigens, free bovine serum albumin (BSA) was orally administered to Balb/c mice in different vehicles: a 0.3% sodium bicarbonate aqueous solution, and ethyl oleate/0.3% sodium bicarbonate o/w emulsion (1:9 v/v containing 0.01 microM sodium deoxycholate and 1% poloxamer 188) or ethyl oleate containing the previously described surfactive agents. The immune response elicited by the free antigen was enhanced by the use of these substances, especially when the free protein was administered as an oil suspension containing the surfactive agents. However, when protein loaded 1 microm PLGA particles were orally administered, the use of these enhancers did not result in an improvement of the serum IgG responses, and only the suspension of the spheres in ethyl oleate containing the poloxamer and the bile salt elicited a similar immune response to that achieved with their suspension into an aqueous solution without any enhancer, which suggests that these enhancers are not capable of increasing the absorption of particulated antigens.

CpG oligodeoxynucleotide enhances immunity against blood-stage malaria infection in mice parenterally immunized with a yeast-expressed 19 kDa carboxyl-terminal fragment of Plasmodium yoelii merozoite surface protein-1 (MSP1(19)) formulated in oil-based Montanides

The 19kDa carboxyl-terminal fragment of Plasmodium yoelii merozoite surface protein-1 (MSP1(19)), an analog of the leading falciparum malaria vaccine candidate, induces protective immunity to challenge infection when formulated with complete/incomplete Freund's adjuvant (CFA/IFA), an adjuvant unsuitable for use in humans. In this study, we investigate Montanide ISA51 and Montanide ISA720 as well as CpG oligodeoxynucleotide (ODN) as adjuvants for induction of immunity to MSP1(19). Mice immunized with MSP1(19) adjuvanted with Montanide ISA51 were protected even though some mice experienced low-grade parasitemia before resolving the infection. Mice immunized with MSP1(19) adjuvanted with Montanide ISA720 showed delayed patent parasitemia with all mice ultimately succumbing to infection. Interestingly, when the synthetic CpG ODN 1826 was included in either Montanide formulation, mice were completely protected with no parasites detected in the blood. MSP1(19)-specific antibodies in MSP1(19)-immunized mice adjuvanted with Montanide ISA51 or Montanide ISA720 showed predominantly IgG1 antibody and low levels of IgG2a. CpG ODN 1826 significantly enhanced both IgG1 and IgG2a antibody responses in Montanide ISA51-adjuvanted mice but significantly enhanced only the IgG2a antibody response in Montanide ISA720-adjuvanted mice. To investigate the relative roles of antibody and CD4(+) T cells in protection, MSP1(19)-immunized mice adjuvanted with Montanide ISA720 and CpG ODN 1826 were depleted of CD4(+) T cells just prior to challenge. Results showed that three of nine immunized/T cell depleted mice died following infection. These results suggest that antibody and CD4(+) T cells are critical for protection following immunization with MSP1(19) adjuvanted with Montanide and CpG ODN and that the formulation of a human malaria vaccine candidate in Montanide ISA720 or ISA51 together with human compatible CpG ODN would be useful for improving efficacy.

Safety and immunogenicity of a three-component blood-stage malaria vaccine in adults living in an endemic area of Papua New Guinea

A Phase I safety and immunogenicity study with a three-component blood-stage malaria vaccine was conducted in adult male subjects living in an endemic area of Papua New Guinea. The preparations were recombinant proteins which corresponded to parts of the two merozoite surface proteins of Plasmodium falciparum (MSP1 and 2), and of the ring-infected erythrocyte surface antigen (RESA). The three proteins were emulsified with the adjuvant Montanide ISA720. Ten subjects were injected twice (four weeks apart) with the vaccine formulation and two with the adjuvant alone. Mild pain at the site of injection was reported by about half of the subjects but no systemic reaction related to the formulation occurred. There was a sharp rise in geometric mean stimulation index after the second dose compared to baseline for MSP1 and RESA, while the rise was small for MSP2. Geometric mean antibody titres increased for MSP1 during the study, whereas they hardly changed for MSP2 and RESA. The vaccine formulation was safe when used in an already immune population. The vaccine induced good cellular responses, especially for MSP1 and RESA. Boosting of humoral responses was weak, probably because of high baseline antibody levels.

The V3 loop based multi-epitope polypeptide TAB9 adjuvated with montanide ISA720 is highly immunogenic in nonhuman primates and induces neutralizing antibodies against five HIV-1 isolates

In a previous work we selected montanide ISA720 (M-ISA720) among different adjuvants for the vaccination with a V3 loop based multi-epitope polypeptide TAB9. In this paper we present the evaluation of the toxicity and immunogenicity of this formulation in non-human primates. TAB9 in M-ISA720 was highly immunogenic in macaques (Macaca fascicularis) inducing antibodies against TAB9 in all animals after one inoculation and a strong anamnestic response after booster injections. Furthermore 97% of the V3 peptides included were recognized by TAB9 sera. No differences between doses of 200 microg and 1 mg of TAB9 in M-ISA720 were observed after four immunizations. Neutralizing antibodies against five HIV-1 isolates were detected in most animals. Animals remain healthy throughout the study and did not show lesions at the inoculation site.

Peptide based cytotoxic T-cell vaccines; delivery of multiple epitopes, help, memory and problems

Synthetic CD8+ cytotoxic T-lymphocyte (CTL) peptide epitope based vaccines are being developed against a number of human diseases. Here we describe extensive preclinical testing of peptide epitope vaccines formulated with a protein as a source of CD4 help and Montanide ISA 720, an adjuvant currently in human clinical trials. Such water-in-oil formulations could effectively co-deliver several peptide epitopes and simultaneously induce multiple independent CTL responses. The efficiency of CTL induction by some peptides was, however, dependent on the aqueous buffer conditions, with poor performance correlating with non-covalent peptide oligomerisation. Any of a number of proteins currently used in human vaccines could supply CD4 help and no difference in CTL induction was obtained if the CD4 response was amnestic or a primary. Peptide immunisation was found to induce long term CTL memory and the recall of protective responses did not depend on an amnestic CD4 response. Slow pyroglutamic acid formation and rapid oxidation of methionine residues was observed in water-in-oil formulations, however, the latter had no effect on CTL induction. These data highlight the need to monitor for potential deleterious chemical events and interpeptide interactions, but illustrate that peptide based vaccination can effectively deliver multiple epitopes, in conjunction with any protein, and induce protective memory.

Nasal and parenteral immunizations with diphtheria toxoid using monoglyceride/fatty acid lipid suspensions as adjuvants

A novel suspension system was developed where monoglycerides were formulated together with fatty acids and subsequently admixed with antigens. In the present study, diphtheria toxoid was used as a model antigen primarily due to its weak immunological properties as well as to its importance as a future human vaccine for mucosal, particularly nasal immunization. The formulations were administered parenterally and/or nasally to mice whereafter the immune response was determined. In the present study, we have shown that mono-olein/oleic acid vesicles enhance the immunogenicity of admixed diphtheria toxoid in mice to the same level as Alum adsorbed (or Freund's complete adjuvant) when administered parenterally or nasally. It was also shown that the immunogenicity was linked to the length of the acyl chain of the lipids, where shorter acyl chains resulted in reduced titers. Furthermore, shorter acyl chains also gave rise to more pronounced toxic reactions at the injections sites, such as necrosis and alopeci, both of which were lacking when the optimal formulation consisting of mono-olein and oleic acid was used. Thus, this lipid matrix has in our view a great potential as an immunological adjuvant with an exceptionally simple and efficient preparation procedure without organic solvents and with low cost endogenous lipid based raw materials.

Characterization of monoclonal antibody reactive with 10-hydroxy-12(Z)-octadecenoic acid (10-OHODA) and its demonstration in cultured human macrophages

10-Hydroxy-12(Z)-octadecenoic acid (10-OHODA) has an inhibitory effect on the tension of papillary muscles in isolated guinea-pig hearts. To establish an immunoassay for 10-OHODA a mouse monoclonal antibody (MoAb), YM-1, was produced. In order to evaluate the ability of this MoAb to recognize various 10-OHODA analogs including leukotoxin (9, 10-epoxy-12-octadecenoic acid, LTx), a sensitive enzyme-linked immunosorbent assay (ELISA) was developed using the avidin-biotin complex (ABC). The detection limit for 10-OHODA was as low as 0.5 ng in this system. In order to demonstrate the presence of 10-OHODA in living cells, macrophages derived from the human leukemia cell line THP-1 by adding 160nM phorbol 12-myristate 13-acetate (PMA) were exposed to 95% O2, and 5% CO2 for 24 h. 10-OHODA and other fatty acids were extracted from the exposed macrophages with diethylether after phospholipase A2 treatment. The 10-OHODA content was determined using the new ELISA, and 18.5 ng 10-OHODA was detected in the macrophages exposed to the high oxygen concentration (1 x 10(6) cells).

Phase I trial in humans of an oil-based adjuvant SEPPIC MONTANIDE ISA 720

Seppic MONTANIDE ISA 720 is a metabolizable oil adjuvant that has given good results in animals with recombinant malarial antigens. Twelve human volunteers were given increasing intramuscular doses of MONTANIDE ISA 720, ranging from 0.6 to 1.8 ml. The adjuvant was well tolerated with only minor local effects, including tenderness, local swelling and discomfort on use. MONTANIDE ISA 720 may prove to be an acceptable and effective adjuvant for use in people.

Immunological basis of toxic oil syndrome (TOS)

The toxic oil syndrome (TOS), a multisystemic disease, that occurred in Spain in 1981, was caused by the ingestion of rapeseed oil denatured with 2% aniline. Due to the clinical course of the disease, immunopathological mechanisms have been suspected but a direct connection was never demonstrated. To analyse this possibility, we determined several immunological parameters in the sera of patients with TOS and without the disease, using a case-control design: total immunoglobulins, IgG and IgE antibodies against different toxic agents (oleylanilide, aniline, linoleyl-anilide, and 3-phenylaminopropane-1-2-diol), autoantibodies, cytokines (IL-4, IL-6, TNF, GM-CSF) and soluble receptors (sCD23 and sIL-2R). We detected high levels of sIL-2R in TOS patients compared to controls (P < 0.0001). A higher levels of sCD23 and IgE were also found. In addition, the response to oleyl-anilide of peripheral blood lymphocytes from TOS patients was studied and a significant proliferative response in 30% of TOS patients versus 5% controls was observed. Our data support the implication of the immune system in the acute phase of TOS, with a possible activation of T-cells and release of cytokines, that could explain some of the clinical findings in this phase of the disease.

Isotype-restricted hyperimmunity in a murine model of the toxic oil syndrome

The toxic oil syndrome is characterized by IgE elevation and eosinophilia, as well as scleroderma-like skin manifestations and other symptoms of autoimmune disease. Fatty acid anilides, found in large amounts in adulterated cooking oil, were suspected to be the etiologic agent in this disease. The capacity of oleic acid anilide to induce features of autoimmunity in vivo was investigated. B10.S mice were continuously treated i.p. with oleic acid anilide for 6 wk by using osmotic pumps. A significant increase in IgE and IgM serum levels was observed after 1 to 3 wk; subsequently five of six mice developed IgG1 levels 3.5- to 10-fold higher than the controls. Anilide-treated mice developed splenomegaly with a 2.1- and a 3.5-fold increase in IgM- and IgG-bearing splenocytes, respectively, and a 5.6- and 29-fold elevation in functional IgM- and IgG-secreting cells, respectively. Increased serum levels of predominantly IgM antibodies to histone, denatured DNA, and DNP as well as rheumatoid factor were detected. In vivo expression in the spleen of 10 cytokine genes was also examined, and mRNA encoding IL-1 beta and IL-6 were significantly elevated in splenocytes of anilide-treated mice. The enhanced Ig production suggests that anilide induced a cytokine-mediated polyclonal activation of B cells. Elicitation of IgM antibodies to denatured forms of autoantigens indicates that anilide treatment partially broke autoimmune tolerance in these mice. Anilide-treated mice may be a useful animal model for further exploring the mechanism and pathogenesis of systemic autoimmunity in the toxic oil syndrome.

The role of cytochrome b5 in delta 12 desaturation of oleic acid by microsomes of safflower (Carthamus tinctorius L.)

The electron donors for the membrane-bound fatty acid desaturases of higher plants have not previously been identified. In order to assess the participation of cytochrome b5 in microsomal fatty acid desaturation, the cytoplasmic domain of microsomal cytochrome b5 was purified from Brassica oleracea, and murine polyclonal antibodies were prepared. The IgG fraction from ascites fluid inhibited 62% of NADH-dependent cytochrome c reduction in safflower (Carthamus tinctorius L.) microsomes. These antibodies also blocked desaturation of oleic acid to linoleic acid in lipids of C. tinctorius microsomes by 93%, suggesting that cytochrome b5 is the electron donor for the delta 12 desaturase.

Natural seric anti-fatty acid antibodies in multiple sclerosis

Naturally occurring anti-oleic acid conjugate antibodies were detected in human sera using an adapted direct immunoenzymatic assay. They were present to a higher level in the sera of patients with multiple sclerosis in acute relapse compared to patients with other neurological diseases or healthy subjects and even patients with multiple sclerosis in progressive form.

Immunogenicity of fatty acid anilides in rabbits and the pathogenesis of the Spanish toxic oil syndrome

Fatty acid anilides, the major xenobiotic found in the cooking oils responsible for the Spanish toxic oil syndrome, are immunogenic for rabbits as ascertained by a skin test reaction, the characterization of specific antibodies against anilides and the immunofluorescent detection of 'anilide dependent antigens' in tissue slices from treated animals.

Hypersensitivity to mineral oil in the domestic fowl

Domestic fowl were found to be hypersensitive to a second injection of highly purified mineral oil if they had been primed 3 weeks previously with oil in the presence of mycobacteria. This response did not appear to be related to impurities originally present in the oil or introduced into it during sterilization, and did not follow priming with mycobacteria in vegetable oil or in saline. The reaction at the challenge site was prolonged and developed a characteristic histology identical to that found at the priming site. It is postualted that the hypersensitivity seen has an immunological basis and that birds are able to respond to antigenic determinants formed by long chain aliphatic hydrocarbons.