A placebo-controlled clinical phase I trial with combined anti-HIV-1 and anti-interferon-alpha immunization.
Explore the source record for details and available documents.
AIDS Vaccines↗
Biomedical subjects
B Bizzini
Publications and source records attributed to B Bizzini.
Repair of the in vitro HIV-1-induced immunosuppression and blockade of the generation of functional suppressive CD8 cells by anti-alpha interferon and anti-Tat antibodies.
The acute human immunodeficiency virus type 1 (HIV-1) infection of activated peripheral blood mononuclear cells (PBMCs) from normal donors results in inhibition of cell proliferation and generation of functional suppressive T cells. Cultured HIV-1 infected PBMCs but not uninfected PBMCs, following irradiation, can inhibit the proliferation of antigen-activated autologous T cells in a dose-dependent way. CD8+ cell subpopulation is responsible for this inhibition. The presence of anti-alpha interferon (IFN alpha) and anti-Tat antibodies in the culture medium counteracts the HIV-1-induced immunosuppression and prevents the generation of suppressive T cells by these PBMCs. The reported data should have major implications for strategies of AIDS treatment which, in association with antiviral drugs, aim at targetting immune disorders.
Acquired Immunodeficiency Syndrome↗
Absence of clinical, virological, and immunological signs of progression in HIV-1-infected patients receiving active anti-interferon-alpha immunization: a 30-month follow-up report.
Twenty-seven HIV-1-infected patients, 16 at early stage of disease and without concomitant antiretroviral therapy and 11 at more advanced stage of disease receiving antiretroviral therapy, have been followed since their enrollment, November 1992 and July 1993, respectively, in phase I/II studies to evaluate safety and immunogenicity of an anti-interferon-alpha (IFN-alpha) vaccine, aimed at modulating the impaired cytokine network in AIDS patients by counteracting IFN-alpha overproduction. We compared clinical, virological, and immunological markers of disease progression, including circulating IFN-alpha levels in a 24- to 30-month follow-up period with those of 62 patients fulfilling the same enrollment criteria and comparable for sex, risk factor, and age, regularly followed at our center. Anti-IFN-alpha immunization consisted of four-six intramuscular injections 1 month apart of a water-in-oil emulsion of 500 micrograms formalin-inactivated recombinant IFN-alpha-2b (iIFN-alpha) followed by intramuscular injections of 250 micrograms iIFN-alpha adsorbed onto calcium phosphate every 3 months. Neither clinical deterioration nor a CD4+ cell count decrease from pretreatment values was observed in IFN-alpha-immunized patients in the follow-up period, whereas clinical and immunological disease progressions were observed among open-comparison patients. Furthermore, statistical analysis showed a strong association between occurrence of clinical manifestations and high circulating IFN-alpha titers, while nonprogression of IFN-alpha-immunized patients was associated with decreased levels of circulating IFN-alpha.
Adolescent↗
Tetanus toxin inhibits spontaneous quantal release and cleaves VAMP/synaptobrevin.
Tetanus toxin decreased the frequency of spontaneous events at the electric organ of Torpedo marmorata. This reduction was up to 70% in poisoned electric organ. According to distribution analysis of miniature end plate currents, only a subpopulation of events which have small amplitudes were recorded after poisoning. Furthermore, isolated cholinergic nerve terminals showed a decrease in VAMP/synaptobrevin when poisoned with tetanus toxin under similar conditions. The relationship between the two effects of the toxin, i.e. inhibition of vesicle exocytosis and peptidase activity on synaptobrevin, is discussed.
Acetylcholine↗
Biological effect of active anti-IFN alpha immunization in HIV-infected patients.
Circulating interferon (IFN) was investigated in HIV-1 seropositive patients by measuring the IFN alpha antiviral effect in the serum. While serum of healthy seronegative individuals exhibits an antiviral effect, not due to IFNs, considered as background, serum of seropositive patients showed an additional antiviral effect due to the abnormal presence of IFN alpha. Increased titers of IFN alpha were found in the course of the HIV infection and seemed to correlate with the evolution of AIDS disease. Furthermore, patients immunized against IFN alpha had both stabilized CD4 cell count and decreased IFN alpha in their serum. HIV-1-infected patients also exhibited higher titers of natural anti-IFN antibodies than seronegative controls and the level of specific antibodies (Abs) markedly increased in immunized patients. Finally, serum from immunized patients, when compared to seronegative controls, exhibits an interferon neutralizing capacity.
Acquired Immunodeficiency Syndrome↗
"Kinoids": the basis for anticytokine immunization and their use in HIV infection.
HIV infection is characterized, at least in part, by the dysregulation of the cytokine network. Both IFN gamma and IFN alpha are occasionally overproduced. These cytokines could participate in the HIV-induced immunosuppression. To enable a HIV-infected organism to promote an immune reaction against the virus, the immune competence should tentatively be restored by counteracting the overproduction of IFN alpha because of its well known antiproliferative properties. For this purpose, IFN alpha was chemically converted into a biologically inactive, but still immunogenic product, which we termed "kinoid", reminiscent of that of bacterial toxins which have been transformed into toxoids for vaccination. The "kinoid" derived from IFN alpha showed to be well tolerated and immunogenic, since its administration to experimental animals and humans should result in no untoward reactions, while eliciting the production of anti-IFN alpha antibodies. Active "kinoid" immunization should permit to counteract the overproduction of the corresponding cytokine when involved in pathogenesis. Another alternative, although less attractive than active anti-kinoid vaccination, is passive immunization by administering anti-kinoid antibodies. Biological antagonists of cytokine, as well as gene therapy should also be taken into consideration.
Acquired Immunodeficiency Syndrome↗
Anti-alpha interferon immunization: safety and immunogenicity in asymptomatic HIV positive patients at high risk of disease progression.
A randomized, placebo-controlled trial was designed to evaluate safety and immunogenicity of an anti-cytokine vaccine in high risk HIV-positive patients. This strategy was aimed to modulate the impaired cytokine regulation in AIDS. Twelve asymptomatic patients on antiretroviral therapy for at least 1 year and with CD4 cell counts between 100-300/mm3 were randomized to receive adjuvanted formol-inactivated interferon alpha-2a (IFN alpha) and continue the current antiretroviral treatment, whatever it was, or to receive the adjuvant alone and the current antiretroviral treatment. All patients received 4 i.m. injections monthly, followed by booster injections every 3 months. Clinical status, immunology and virology were monitored. Immune response to vaccination was evaluated in term of antibody detection (ELISA) and serum anti-IFN alpha neutralizing capacity. Only local discomfort and transient fever were reported. All vaccines except one showed increased levels of anti-IFN alpha Abs and developed serum IFN alpha neutralizing capacity. Viral load did not increase in vaccinees while it remained unchanged or even increased in placebo-treated patients. None of them showed HIV-related symptoms and all had their CD4 cell counts stabilized over 18 months, whereas 2 placebo-treated patients developed full-blow AIDS. In conclusion, anti-IFN alpha vaccine was safe and immunogenic. Stable clinical and immunological status over 18 months was observed in vaccinees coupled to increased serum IFN alpha neutralizing capacity.
Acquired Immunodeficiency Syndrome↗
Production in rabbits of high levels of anti-HIV-1 gp160 antibodies.
The production of anti-HIV-1 gp160 antibodies was obtained in rabbits given gp160 either in saline or adsorbed onto calcium phosphate. Immunization with gp160 in saline induced the formation of antibodies directed to the p18 protein, whereas the gp160 adsorbed onto calcium phosphate elicited antibodies recognizing the gp160, p55, p25 and p18 proteins. Calcium phosphate was found to be a powerful adjuvant and it should be used for potentiating candidate anti-HIV vaccines.
Adjuvants, Immunologic↗
HIV-1 soluble antigens induced CD8+ cytotoxic T-cell responses in an immunized individual.
In an attempt to determine whether immunization of healthy HIV-1 seronegative individuals with a soluble gp160 candidate vaccine could induce an anti-HIV specific immune response, volunteers were immunized by two injections of a water-in-oil emulsion containing a mixture of gp160 antigen together with selected peptides. Following immunization, lymphocytes were collected and stimulated in vitro with autologous HIV-1-infected cells. The results showed that immunization with soluble HIV-1 envelope was able to generate CD3+ CD8+ CTLs directed to gp160 antigen. The CTL response was restricted to class I molecule HLA-A2. The CTL response was comparable to that elicited by immunization with HIV-1-envelope recombinant vaccinia virus.
AIDS Vaccines↗
Evidence for an antiviral effect and interferon neutralizing capacity in human sera; variability and implications for HIV infection.
The antiviral effect (AVE) and interferon neutralizing capacity (INC) of sera originating from either seronegative or HIV-infected individuals were determined. As a rule, sera from seropositive subjects exhibited higher AVE titers than sera from seronegative individuals. Similarly, the INC of sera from HIV-infected patients, was most often stronger than that of sera from seronegative individuals. Furthermore, sera from HIV-infected patients actively immunized with i-IFN alpha invariably expressed INC in response to treatment, which was not the case for sera from control unimmunized patients. All sera from HIV-infected patients were found by ELISA to contain antibodies specifically directed to IFN alpha.
Acquired Immunodeficiency Syndrome↗
Contribution of alpha interferon (alpha IFN) to HIV-induced immunosuppression.
In the present investigation we have shown that PBLs taken from HIV-positive patients suppressed T-cell proliferation when cultured for at least 12 days. When infected In vitro with HIV-1, these cells become suppressive after 6 days. PBLs collected from seronegative individuals turned out to be non-suppressive even after prolonged culturing. However, when infected in vitro with HIV they were found to be cytostatic also after 6 days. This anti-immune activity, related to HIV infection, is mediated, at least in part, by alpha IFN, since about 50% of this HIV associated activity could be quenched by alpha IFN antibodies. We also showed that this T-cell cytostasis is associated with CD8+ cells. In view of a possible use of suppressive cells for T-cell vaccination, we verified that such cellular functions were abolished by aldehyde treatment.
Acquired Immunodeficiency Syndrome↗
Involvement of alpha-interferon in HIV-1 induced immunosuppression. A potential target for AIDS prophylaxis and treatment.
Since the immune system is impaired in the course of HIV-infection, the purpose of any AIDS vaccine therapy should be the restoration in the patient of an adequate immunocompetence to enable him to respond to the antigenic stimulus represented by the virus. In the present investigation we have shown the antiproliferative action on activated T-cells in culture of: sera taken from HIV-infected, but not seronegative individuals; T lymphocytes taken from seronegative subjects and infected in vitro with HIV but not non infected cells; native alpha-IFN and the time-dependent inactivation of this activity by formaldehyde treatment of alpha-IFN. Thus is confirmed the major contribution provided by alpha-IFN to the immunosuppression occurring in the course of HIV-infection. These results also strongly support the new AIDS vaccine therapy strategy based on the administration to HIV-infected patients of inactivated, but still immunogenic alpha-IFN. To the alpha-IFN treatment could also be combined the administration of fixed autologous suppressive cells. The induction of gamma-IFN in addition to alpha-IFN production by stimulation of cells from healthy donors with gp120 should encourage the use of a vaccine combining both inactivated alpha-IFN and gamma-IFN. On the other hand, the IL-12 cytokine with its potential to restore compromised cell-mediated functions associated with HIV infection should also be a valuable adjuvant treatment.
Acquired Immunodeficiency Syndrome↗
Effect of purified IgGs from HIV-1-infected and non infected individuals on immune activation.
The purification and analysis of IgGs from sera of HIV-1-infected and non infected individuals are reported. The effect of antibodies purified from sera of infected individuals on antigen-induced T cell proliferation was investigated in relation to their possible involvement in an autoimmune reaction in AIDS, in view of the previously unravelled striking peptide similarities between HIV-1 gp120 and the immunoregulatory CD4 and Fas molecules. However, our data do not allow definite conclusions to be drawn. The necessity of purifying antibodies against specific peptides to show their direct effect on T-cell activation is further stressed.
Acquired Immunodeficiency Syndrome↗
Pathogenic disorders involved in immunosuppression and T cell depletion characterizing AIDS.
Four cardinal immune disorders interacting with each other may promote the progressive T cell depletion and immunosuppression characterizing AIDS. Immune activation of HIV-1 infected T4 cells leads to virus release and premature cell death. Both virus release with its resulting viral load and dead cells are the source of gp120 stimulus. Anergy of non-infected CD4 cells, resulting in cytokine dysregulation may be promoted by impairing the CD4-MHC interaction during CD4 cell activation either directly through the SLWDQ pentapeptide identity with the CD4 molecule and the CD4 binding region or through a gp120-induced autoimmune reaction to CD4. Overproduction of IFN alpha, the known antiproliferative and cytolytic cytokine may promote in a paracrine manner to neighbouring cells the immunosuppression generated by the lack of IL2 secretion following CD4 cell anergy. Apoptosis of activated non infected T cells could be induced by effector components of the autoimmune reaction (CTL, Lymphotoxins or Abs?) directed towards the 2 consensus gp120 sequence identity/similarity (INCTR and FYCNST) shared with the APO/Fas molecule. These two sequences are known as immunodominant sites of the gp120. Furthermore, IFN alpha overproduction may also render circulating memory T cells competent to apoptosis by upregulating the cascade of metabolic events leading to programmed cell death.
Acquired Immunodeficiency Syndrome↗
Automat: a novel software system for the systematic search for protein (or DNA) similarities with a notable application to autoimmune diseases and AIDS.
Automat is a novel program which finds exhaustively all the oligopeptide segments shared by a given protein of any size with the proteins of a whole databank. It allows the user to collect statistics on the composition of the sequence studied in reference to the databank used. We present here the rationale and the algorithm underlying this powerful software. Besides its immediate interest for identifying efficiently similarities between proteins (or DNAs), biological applications of this software have already been described in the case of HIV-1 viral proteins, and Automat should prove useful also for studying more generally autoimmune diseases.
Acquired Immunodeficiency Syndrome↗
Adjuvants--a balance between toxicity and adjuvanticity.
Adjuvants have been used to augment the immune response in experimental immunology as well as in practical vaccination for more than 60 years. The chemical nature of adjuvants, their mode of action and the profile of their side effects are highly variable. Some of the side effects can be ascribed to an unintentional stimulation of different mechanisms of the immune system whereas others may reflect general adverse pharmacological reactions. The most common adjuvants for human use today are still aluminium hydroxide, aluminium phosphate and calcium phosphate although oil emulsions, products from bacteria and their synthetic derivatives as well as liposomes have also been tested or used in humans. In recent years monophosphoryl lipid A, ISCOMs with Quil-A and Syntex adjuvant formulation (SAF) containing the threonyl derivative of muramyl dipeptide have been under consideration for use as adjuvants in humans. At present the choice of adjuvants for human vaccination reflects a compromise between a requirement for adjuvanticity and an acceptable low level of side effects.
Adjuvants, Immunologic↗
Envelope protein and p18(IIIB) peptide recognized by cytotoxic T lymphocytes from humans immunized with human immunodeficiency virus envelope.
Cytotoxic T cells are the main antigen-specific effector cells of the cellular immune system and MHC class I restricted cytotoxic T-lymphocyte (CTL) responses in mice, acting against the HIV-1 envelope protein, are known to be predominantly directed against an amino acid sequence in the third hypervariable domain. We have investigated the epitope specificity of anti-HIV-1 CTL in healthy human volunteers inoculated with a recombinant vaccinia expressing the HIV-1 gp160 envelope gene. Their isolated lymphocytes were stimulated in vitro with autologous HIV-1 infected cells. Our results show that immunization with recombinant virus is able to generate virus-specific CTLs to the HIV-1 gp160 envelope protein and to a 15-residue synthetic peptide corresponding to a highly variable region of the envelope p18(IIIB). The CTL response was restricted by class I MHC molecules HLA-A2 and A3 that commonly occur in the human population.
AIDS Vaccines↗
Skin-window-induced inflammation in breast cancer patients: a study of macrophage migration.
A decreased number of macrophages has previously been demonstrated by means of skin-window assays in operable breast cancer patients. However, in this type of cellular inflammatory response, a varying intensity of cellular activation, cellular recruitment and macrophage chemotaxis exists. In this study, we performed skin windows after stimulation by a chemo-attractant (FMLP) and a recall antigen (Candidin-latex). Cellular responses were classified in 19 breast cancer patients according to the presence (A+) or absence (A0) of macrophage activation by comparison to healthy controls. In 13 A0 patients, the admixture of a cytokine (IFN alpha) and an immunomodulator (P40) to one agent or the other or both resulted in the restoration of macrophage functions. Our study shows that uniform cellular responses to chemo-attractants and antigens are observed in healthy and not immunocompromised individuals as assessed by skin-window tests. However, the cellular response recorded in immunodeficient cancer patients is altered. It also shows that the admixture to chemoattractants and antigens of particular cytokines or better still of an immunomodulator displaying a wide spectrum of activity offers a way of restoring macrophage functions. Individual responses to immunotherapy in clinical oncology may be related to such results.
Adjuvants, Immunologic↗