Propofol hemisuccinate suppression of experimental autoimmune encephalomyelitis.

Propofol hemisuccinate is a prodrug water soluble form of the lipophilic, phenolic compound propofol (2,6-di-isopropylphenol), that is the active ingredient in the widely used anesthetic agent Diprovan. Propofol binds to GABA(A) receptors but also has a phenolic structure that confers antioxidant properties to the molecule. The effects of propofol hemisuccinate in rat experimental autoimmune encephalomyelitis (EAE) were studied using different doses and time regimes. Propofol hemisuccinate, 100 mg/kg given three times a day from day 7 or day 12 until day 16 after disease initiation, significantly reduced maximal EAE score. Histology studies supported the clinical findings demonstrating reduction in the inflammatory response in the lumbar spinal cord in animals treated with propofol hemisuccinate. Decreased levels of nitrotyrosine and unchanged levels of induced nitric oxide synthase suggest propofol hemisuccinate crossed the blood brain barrier and exerted its effects by lowering reactive oxygen species levels. The results suggest that propofol hemisuccinate may provide an alternative mode of treatment for acute exacerbations of multiple sclerosis.

Vaccination with cell immunoglobulin mucin-1 antibodies and inactivated influenza enhances vaccine-specific lymphocyte proliferation, interferon-gamma production and cross-strain reactivity.

Influenza virus causes a contagious and potentially serious infection of the upper respiratory tract. While neutralizing antibodies are protective against infection, the problem of antigenic drift remains, requiring the constant monitoring and development of new vaccines. The magnitude of this situation is underscored by the emergence of new potentially human pathogenic influenza strains, avian H5N1 being the most recent example. We present evidence that antibodies against T cell immunoglobulin mucin-1 (TIM-1), a recently identified immunomodulatory molecule, stimulate cellular immunity against influenza viruses and cross-strain immune reactivity. To determine potential immunostimulatory properties of anti-TIM-1, mice were vaccinated with inactivated influenza virus in the presence or absence of TIM-1-specific monoclonal antibodies. Development of cellular immunity against both the influenza strain used for immunization and serotypically distinct virus strains was monitored 3 weeks after vaccination by determining antigen-specific lymphocyte proliferation and cytokine production. Results show that TIM-1 antibodies enhance antigen-specific cellular proliferation (P < 0.05) and interferon (IFN)-gamma production (P < 0.01). Using blocking anti-CD4 and CD8 antibodies, it was observed that antigen-specific cellular proliferation is CD4-dependent and that the majority of proliferating cells are CD4+. Finally, vaccination with inactivated influenza virus with TIM-1 antibody results in the significant (P < 0.001) induction of proliferation and IFN-gamma production upon stimulation with one of three serologically distinct strains. TIM-1 antibodies demonstrate an adjuvant effect promoting antigen-specific cellular proliferation and IFN-gamma production, which are important for the promotion of cell-mediated immunity. These results are the first to suggest that TIM-1 antibody may serve as a potent adjuvant in the development of new influenza virus vaccines.

Novel membrane-bound GM-CSF vaccines for the treatment of cancer: generation and evaluation of mbGM-CSF mouse B16F10 melanoma cell vaccine.

Cancer vaccines composed of tumor cells engineered to secrete granulocyte-macrophage colony-stimulating factor (GM-CSF) are currently being clinically evaluated. To enhance the immunogenicity of GM-CSF-secreting tumor cell vaccines, a novel approach expressing GM-CSF as a membrane-bound form (mbGM-CSF) on the tumor cell surface was investigated. The intent was to enhance antigen presentation by increasing interactions between the tumor cell lines in the vaccine and GM-CSF receptor positive antigen presenting cells (APC), notably the patient's Langerhans cells residing within the intradermal injection site. B16.F10 cells engineered to express either membrane-bound or secreted GM-CSF were compared in the B16.F10 mouse melanoma model. We observed that mbGM-CSF on the tumor cell surface retarded growth and induced protective immunity to subsequent wild-type tumor challenge more effectively than tumor cells secreting GM-CSF. Vaccination with irradiated mbGM-CSF B16.F10 also provided strong protection from wild-type tumor challenge, improved therapeutic effects against established tumors, and retarded lung metastases. These results demonstrate that mbGM-CSF B16.F10 cells can induce strong systemic immunity that protects against and therapeutically treats B16.F10 melanoma more effectively than analogous vaccines containing only secreted GM-CSF. These data warrant further development and clinical testing of mbGM-CSF tumor cell vaccines.

Antigenic and immunologic characterization of an allogeneic colon carcinoma vaccine.

We report the immunological characterization of three colon carcinoma cell lines, COLO 205, SW620 and SW403, which we selected to combine with cytokine-secreting fibroblasts for the development of an allogeneic tumour cell vaccine. The cell lines expressed HLA-A2 as well as shared tumour-associated antigens (TAAs) representative of colon carcinomas: CEA, Ep-CAM, MUC1, HER2/neu and MAGE antigens. They did not secrete high levels of the immunosuppressive factors TGF-beta, IL-10 or prostaglandins. The lines presented TAAs in a manner recognized by immune effector cells, which was demonstrated by the lysis of SW620 by HLA-A2-restricted anti-p53 cytotoxic T lymphocytes (CTL). COLO 205 and SW620 were genetically modified to express the co-stimulatory molecule CD80 (B7.1), which increased the ability of the cells to stimulate CTL in vitro. CTL clones derived from HLA-A2+ peripheral blood mononuclear cells stimulated with the CD80-expressing lines lysed the stimulator cell and an HLA-A2+ colon cancer cell line, but did not lyse an isogeneic fibroblast line or an HLA-A2- colon cancer cell line. CTL clones derived from colon carcinoma patients immunized with an allogeneic vaccine containing these lines demonstrated killing of autologous tumour cells, the vaccine cell lines and other HLA-A2+ colon cancer cell lines, but not fibroblasts isogeneic to certain of the target cell lines. Our studies demonstrate that these colon carcinoma cell lines express shared TAAs that can induce CTLs which recognize and lyse other colon carcinoma cells, and support the continued clinical evaluation of the CD80 gene modified allogeneic colon cell/cytokine-secreting fibroblast carcinoma vaccine.

Predictors of HIV-specific lymphocyte proliferative immune responses induced by therapeutic vaccination.

We treated a cohort of 38 HIV-infected individuals with a therapeutic vaccine (REMUNE, HIV-1 Immunogen) in an open label study. We then determined whether baseline parameters, such as CD4 cell count, viral load and IgG levels, were predictive of the magnitude of the HIV-specific lymphocyte proliferative responses (LPRs). We demonstrate herein that there is a significant enhancement from baseline for both HIV and p24 antigen-stimulated LPRs after immunization. Using a responder definition of a stimulation index of >5 on at least two post-immunization time-points, 29/38 (76%) responded to HIV-1 antigen while 27/38 (71%) responded to native p24 antigen. Viral load and total IgG were negatively correlated, while CD4 cell counts were positively associated with the magnitude of the HIV antigen LPR. In a multivariable analysis, baseline CD4 was the best predictor of HIV antigen LPR post-immunization.

Expression of perforin on HIV-1-specific CD8+ lymphocytes after immunization with a gp120-depleted, whole-killed HIV-1 immunogen.

We examined HIV-1 antigen specific intracellular expression of perforin on CD4+ and CD8+ lymphocytes in subjects with chronic HIV-1 infection on antiviral drug therapy after immunization with a gp120-depleted, whole killed HIV-1 immunogen (inactivated, gp120-depleted HIV-1 in IFA, REMUNE). Based upon previous results, we hypothesized that the restoration of adequate T helper immune responses by vaccination against HIV-1 could result in the augmentation of CD8+ lymphocyte immune responses measured as perforin expression. In the current study we observed an increase in the frequency of perforin in CD8+ lymphocytes in HIV infected individuals immunized with a gp120-depleted HIV-1 immunogen while on antiviral drug therapy. Furthermore, the frequency of HIV-specific CD8+ perforin expressing cells correlated with the T helper immune response as measured by the lymphocyte proliferative response (LPR). The induction of such responses with immunization may have direct antiviral consequences and is being studied in ongoing clinical trials.

Vaccination with a CDR2 BV6S2/6S5 peptide in adjuvant induces peptide-specific T-cell responses in patients with multiple sclerosis.

Earlier studies from several groups including ours have documented that patients with multiple sclerosis (MS) have over-expression of activated T-cells from specific TCR V beta families, including BV6S2/S5 (Kotzin et al. [1991] Proc. Natl. Acad. Sci. USA 88:9161--9165; Gold et al. [1997] J. Neuroimmunol. 76:29--38). It has also been established in the rat EAE model that peptide vaccines to the over-expressed V beta 8.2 TCR can prevent MBP induced disease (Vandenbark et al. [1989] Nature 341:541--544). In the current clinical study, 10 patients were vaccinated with 300 microg of BV6S2/6S5 peptide emulsified in incomplete Freund's adjuvant (IFA) and monitored for safety and immunogenicity in a 48-week multicenter, open-label trial. The peptide vaccine was well tolerated and no serious adverse events were observed. Vaccinations induced cell-mediated immunity to the immunizing peptide in eight of 10 patients as demonstrated by lymphocyte proliferation assay (LPA) and delayed-type hypersensitivity (DTH) skin test responses. In summary, these results demonstrate that immunization with TCR BV6S2/6S5 peptide vaccine in MS patients is safe and immunogenic, and supports a larger double-blind placebo controlled trial to determine the clinical efficacy of this approach.

Human immunodeficiency virus (HIV)-specific immune responses are generated with the simultaneous vaccination of a gp120-depleted, whole-killed HIV-1 immunogen with cytosine-phosphorothioate-guanine dinucleotide immunostimulatory sequences of DNA.

OBJECTIVES: We compared the effect of priming with a synthetic oligodeoxynucleotide (ODN) immunostimulatory DNA sequence followed by vaccination with human immunodeficiency virus type 1 (HIV-1) in incomplete Freund's adjuvant (IFA) or HIV-1 antigen alone to the simultaneous administration of immunostimulatory sequences (ISS) with HIV-1 in IFA. METHODS: We examined immune function involving interferon-gamma (IFN-gamma) production, RANTES (regulated upon activation, normal T cell expressed and secreted) production, and lymphocyte proliferation, all of which appear to be augmented in HIV-1-exposed, but uninfected, individuals. RESULTS: We demonstrate that similar levels of antigen-specific IFN-gamma were produced from lymph node cells of the animals immunized with HIV-1 antigen in IFA containing the CpG ODN 1826 (ISS; mean +/- SE = 450.8 +/- 224.3 pg/mL) and the group of animals primed with the ODN before injection with the HIV-1 in IFA (mean +/- SE = 377.7 +/- 294.8 pg/mL) or HIV-1 antigen alone (IFN-gamma = 0 pg/mL). However, the group that received the HIV-1 in IFA plus ISS mounted a stronger lymphocyte proliferation (mean net +/- SE = 29,180 +/- 1,932 cpm) compared to the group primed with the ODN before injection with HIV-1 in IFA (mean net +/- SE = 8,575 +/- 2,978 cpm). Furthermore, the group that received the HIV-1 in IFA plus ISS also mounted stronger beta-chemokine production measured as RANTES (mean +/- SE = 1,217 +/- 267.4 pg/mL) compared to the group that received the ODN before injection with HIV-1 in IFA (mean +/- SE = 129.1 +/- 48.5 pg/mL). Antibody responses from the group that received the HIV-1 in IFA plus ISS also showed a higher p24-specific response that was predominantly of the immunoglobulin G IgG2b isotype. CONCLUSION: These results suggest that the simultaneous administration of the ISS in the HIV-1 in IFA emulsion may be a condidate for testing in non-human primates and in human studies as a therapeutic and preventative vaccine.

The strategy of immunologic control of HIV-1 with structured treatment interruptions (STIs).

Structured treatment interruptions (STIs) have evolved as an experimental approach of interrupting highly active antiretroviral therapy (HAART) similar to cycles of cancer chemotherapy in order to develop immune control of HIV-1. There are multiple, ongoing clinical trials examining interruptions in antiviral therapy with and without immune-based therapies. If successful in developing immune control, STIs may be clinically useful but require large scale clinical trials to prove their utility and safety.

Strength of conjugate binding to plasmid DNA affects degradation rate and expression level in vivo.

In vitro assays have demonstrated the capability of poly-L-lysine to protect plasmid DNA from serum nucleases and cellular lysates. Our purpose was to evaluate the stability and potency of poly-L-lysine-DNA polyplexes after intravenous injection into mice. Polyplexes consisted of 32P-radiolabeled plasmid DNA complexed with poly-L-lysine at specified charge ratios. Variations in conjugate hydrophobicity and levels of modification with polyethylene glycol were investigated. Our results show that, in contrast to in vitro studies, the systemically administered polyplexes exhibited marked DNA degradation in the vascular compartment within 5 min. Substitution of poly-L-lysine epsilon-amino sites with polyethylene glycol or hydrocarbon chains resulted in faster degradation even when complexed at higher charge (+/-) ratios. Use of excess cationic charge in the polyplexes (+/- 2.5) diminished degradation rates only slightly. An analysis was made of the strength of the poly-L-lysine:DNA interaction by competition with poly-aspartic acid. Polyplexes with the strongest binding between conjugate and DNA in the competition assay were also the most stable in blood. However, tighter binding was not enough to fully protect the polyplex in vivo and polyplex DNA was substantially degraded within 10 min. Increased polyplex stability did not correlate with improved in vivo transfection efficiency.

Gene expression monitoring for gene discovery in models of peripheral and central nervous system differentiation, regeneration, and trauma.

Gene expression monitoring using gene expression microarrays represents an extremely powerful technology for gene discovery in a variety of systems. We describe the results of seven experiments using Incyte GEM technology to compile a proprietary portfolio of data concerning differential gene expression in six different models of neuronal differentiation and regeneration, and recovery from injury or disease. Our first two experiments cataloged genes significantly up- or down-regulated during two phases of the retinoic acid-induced differentiation of the embryonal carcinoma line Ntera-2. To identify genes involved in neuronal regeneration we performed three GEM experiments, which included changes in gene expression in rat dorsal root ganglia during the healing of experimentally injured sciatic nerve, in regenerating neonatal opossum spinal cord, and during lipopolysaccharide stimulation of primary cultures of rat Schwann cells. Finally we have monitored genes involved in the recovery phase of the inflammatory disease of the rat spinal cord, experimental allergic encephalomyelitis, as well as those responsible for protection from oxidative stress in a glutamate-resistant rat hippocampal cell line. Analysis of the results of the approximately 70,000 data points collected is presented.

T-helper-cell proliferative responses to whole-killed human immunodeficiency virus type 1 (HIV-1) and p24 antigens of different clades in HIV-1-infected subjects vaccinated with HIV-1 immunogen (Remune).

The discovery of multiple subtypes of human immunodeficiency virus type 1 (HIV-1) worldwide has created new challenges for the development of both therapeutic and preventive AIDS vaccines. We examined T-helper proliferative responses to HIV-1 clade A, B, C, G, and E whole-killed virus and to HIV-1 clade G and B core (p24) antigens in HIV-1-infected subjects taking potent antiviral drugs who received HIV immunogen (Remune) therapeutic vaccination. Subjects who were immunized mounted strong proliferative responses to both whole virus and core antigens of the different clades. These results suggest that a whole-killed immunogen may have broad applications as a therapeutic as well as a preventive vaccine in the current multiclade HIV-1 pandemic.

A double-blind, adjuvant-controlled trial of human immunodeficiency virus type 1 (HIV-1) immunogen (Remune) monotherapy in asymptomatic, HIV-1-infected thai subjects with CD4-cell counts of >300.

We examined the effect of a human immunodeficiency virus (HIV)-specific immune-based therapy in Thailand, where access to antiviral drug therapy is limited. A 40-week trial was conducted with 297 asymptomatic, HIV-infected Thai subjects with CD4-cell counts greater than 300 microl/mm(3). Subjects were randomized to receive either HIV type 1 (HIV-1) immunogen (Remune; inactivated HIV-1 from which gp120 is depleted in incomplete Freund's adjuvant or adjuvant control at 0, 12, 24, and 36 weeks at five different clinical sites in Thailand. Neither group received antiviral drug therapy. The a priori primary endpoint for the trial was changes in CD4-cell counts with secondary parameters of percent changes in CD8-cell counts (percent CD4, CD8, and CD4/CD8) and body weight. Subsets of subjects were also examined for changes in plasma HIV-1 RNA levels, Western blot immunoreactivity, and HIV-1 delayed-type hypersensitivity (DTH) skin test reactivity. There was a significant difference in changes in CD4-cell counts that favored the HIV-1 immunogen-treated group compared to those for the adjuvant-treated control group (P<0.05). On average, for HIV-1 immunogen-treated subjects CD4-cell counts increased by 84 cells by week 40, whereas the increase for the control group was 38 cells by week 40. This increase in CD4-cell count was associated with increased HIV-specific immunogenicity, as shown by Western blotting and enhanced HIV-1 DTH skin reactivity. No significant differences in adverse events were observed between the groups. The results of this trial suggest that HIV-1 immunogen is safe and significantly increases CD4-cell counts and HIV-specific immunity compared to those achieved with the adjuvant control in asymptomatic HIV-1-infected subjects not taking antiviral drugs.

HIV-1-Specific CD4 helper function in persons with chronic HIV-1 infection on antiviral drug therapy as measured by ELISPOT after treatment with an inactivated, gp120-depleted HIV-1 in incomplete Freund's adjuvant.

OBJECTIVE: We hypothesized that treatment of HIV-1-seropositive study subjects receiving potent antiviral therapy with an HIV-specific immune-based therapy would increase HIV-1-specific T-helper immune function. DESIGN: 10 HIV-1-seropositive study subjects receiving antiretroviral therapy were treated with an inactivated, gp120-depleted immunogen in IFA (HIV-1 immunogen, Remune) at baseline, week 12, and week 24. METHODS: The frequency of HIV-1 antigen-stimulated interferon-gamma (IFN-gamma)-producing cells was determined by the ELISPOT assay. RESULTS: Study subjects significantly increased their frequency of HIV-1-stimulated (p <. 001) or p24 antigen-stimulated (p <.01) IFN-gamma-producing cells after one, two, and three treatments of HIV-1 immunogen. Depletion of CD4 cells resulted in the strongest abrogation of the IFN-gamma response. The frequency of HIV-1 (r = 0.64; p =.0002) and p24 (r = 0. 72; p <.001) antigen-stimulated IFN-gamma-producing cells in the CD8-depleted population before and after treatment was associated with the lymphocyte-proliferative response. CONCLUSIONS: Treatment with HIV-1 immunogen significantly enhanced the frequency of HIV-1-specific IFN-gamma-producing cells. Studies are ongoing to determine the relationship between this reversal of HIV-specific anergy and virologic outcomes.

CXCR4 and CCR5 expression on CD4+ T cells in vivo and HIV-1 antigen beta-chemokine production in vitro after treatment with HIV-1 immunogen (REMUNE).

BACKGROUND: The chemokine receptors CXCR4 and CCR5 have been identified as the major coreceptors for HIV-1 on CD4+ cells and macrophages. The natural ligands for these receptors are SDF-1 and the beta-chemokines (MIP-1alpha, MIP-1beta, RANTES), respectively, and are the products of a variety of immune cells, including CD8+ T lymphocytes. STUDY DESIGN/METHODS: We hypothesized that the ability to stimulate the natural ligands for these receptors using an immune based therapy might influence in vivo chemokine receptor expression. RESULTS: In vivo CXCR4 expression remained stable after treatment with an HIV-1 Immunogen (REMUNE), whereas CCR5 expression on CD4+ T cells decreased (p < .05). Furthermore, HIV-1 antigen-specific production of beta-chemokines in vitro was also augmented (P < .05). CONCLUSIONS: These preliminary results suggest that this HIV-1-specific immune-based therapy can stimulate antigen-specific beta-chemokine production in vitro and downregulate CCR5 receptor expression on CD4 cells in vivo.

Enhancement of HIV type 1 antigen-specific CD4+ T cell memory in subjects with chronic HIV type 1 infection receiving an HIV type 1 immunogen.

We examined HIV-1 specific memory helper T immune responses in chronically HIV-infected subjects who received an immune-based therapy (HIV-1 immunogen, Remune). Subjects in this study exhibited significant increases (p < 0.05) in the frequency of helper T memory cells expressing interferon gamma (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha) in response to HIV-1 antigens in vitro. The frequencies of HIV-specific memory T cells increased after successive immunizations and exhibited a correlation with the standard tritiated thymidine incorporation lymphocyte proliferation assay (r = 0.72, p < 0.0008). These results support the notion that HIV-specific memory immune responses can be stimulated in subjects with chronic HIV infection. Further investigations are warranted to determine whether the induction of such responses is associated with virologic control.

Cell-mediated immune responses to autologous virus in HIV-1-seropositive individuals after treatment with an HIV-1 immunogen.

OBJECTIVE: We hypothesized that cell mediated immune responses to an HIV-1 immunogen (whole-killed, gp120-depleted HIV-1 in IFA, REMUNE) would include those to autologous virus. METHODS: Five chronically HIV-1 infected individuals were examined for HIV-specific immune responses to their own virus (autologous viral antigen) after treatment with an HIV-1 immunogen. RESULTS: Subjects had low proliferative responses to HIV and p24 antigens prior to immunization and mounted strong lymphocyte proliferative responses to the immunizing HIV-1 virus, native p24, and autologous viral antigen post immunization. Similarly, subjects produced low amounts of interferon-gamma in response to HIV and p24 antigens prior to immunization and increased their interferon-gamma production in response to HIV-1, native p24, and to autologous antigen post-immunization. Furthermore, beta-chemokine responses measured as migratory inhibitory protein-1beta production were low at baseline in response to HIV-1 and native p24 antigens and were enhanced post immunization to HIV-1, native p24, and autologous antigen. CONCLUSIONS: In this study HIV-specific immune responses to autologous virus were observed after treatment with an HIV-specific immunogen.

HIV-Specific CD4(+) and CD8(+) immune responses are generated with a gp120-depleted, whole-killed HIV-1 immunogen with CpG immunostimulatory sequences of DNA.

We examined the adjuvant effects of a synthetic CpG oligodeoxynucleotide immunostimulatory sequence (ISS) using a whole-killed, gp120-depleted HIV antigen (HIV-1 antigen) in a Lewis rat model. We hypothesized that HIV-1-specific CD4(+) T helper (Th) immune responses could be enhanced when an ISS was combined with an HIV-1 antigen in incomplete Freund's adjuvant (IFA). We also reasoned that if such Th responses were sufficient, such a combination might also induce HIV-specific CD8(+) T cell immune responses. Here we demonstrate that the HIV-1 antigen in IFA combined with ISS stimulates both CD4(+) and CD8(+) HIV-specific immune responses as measured by interferon-gamma (IFN-gamma) in the ELISPOT assay. A strong correlation between these CD4(+) and CD8(+) responses was demonstrated. Furthermore, we found that the HIV-1 antigen in IFA with ISS as an adjuvant stimulated strong antibody responses to core antigen (p24). These studies suggest that the combination of the whole-killed, gp120-depleted HIV-1 antigen in IFA with ISS may be an ideal candidate to test in nonhuman primates and in human studies as a preventive HIV-1 vaccine.

In vitro immune function after vaccination with an inactivated, gp120-depleted HIV-1 antigen with immunostimulatory oligodeoxynucleotides.

We examined the effect of a synthetic oligodeoxynucleotide containing unmethylated CpG immunostimulatory sequences (ISS) as an adjuvant for an HIV-1 immunogen (inactivated, gp120-depleted HIV-1 virus particles). The addition of the ISS to HIV-1 in incomplete Freund's adjuvant (IFA) was the optimal combination for the production of HIV-1-specific immune responses as measured by IFN-gamma (p=0.002) and IgG antibody production. Furthermore, the group that was immunized with HIV/IFA/ISS, as well as the group that received HIV-1 in complete Freund's adjuvant (CFA), stimulated significantly more RANTES (a beta-chemokine) (p=0.002) production from lymph node cells. These results suggest that the addition of CpG immunostimulatory sequences to HIV antigens in IFA may optimize HIV-1-specific immune responses and provides further rationale for the testing of ISS in combination with gp120-depleted whole-killed HIV-1 in IFA as a potential preventive or therapeutic HIV-1 vaccine.