- Email: [email protected]
O.016 Towards effective prophylactic and therapeutic vaccination against HCV
Oral presentations: PS03: HBV: Animal and cellular models
[0~A
phase 1 trial of a novel E1E2/MF59C.1 hepatitis C vaccine candidate in healthy HCV-negative adults (DMID 01-002)
S E Frey 1., G J Gorse 1, A M DiBisceglie 1, D Rosa 2, Z Stamataki 3, J McKeating 3, R Ray 1, S Coates 2, V Schultze 4, S Abrignan 2, M Houghton 2, H Hill 5, R B Belshe 1 1/nterna/
Medicine, Saint Louis University, St. Louis; 2Chiron Corporation, Emeryville, USA, 3Div of Immunity and Infection, Birmingham Univ., Birmingham, United Kingdom, 4Chiron Vaccines, Marburg, Germany, 5The EMMES Corporation, Rockville, USA Background and Objectives: HCV remains a serious world-wide public health problem. To date there is no effective vaccine or therapy. A dose escalation study of HCV E1 E2/MF59C.1 adjuvanted vaccine was conducted to evaluate safety and immunogenicity. Methods: Healthy adults were randomized equally to 3 groups (16 vaccine and 4 placebo recipients). Vaccines were given at 0, 4, 24 and 48 weeks. Results: Sixty subjects ages 18 to 45 were enrolled. Sixty, 55, 52 and 50 subjects received 1, 2, 3, and 4 vaccines in the 01~g, 41~g, 20~g and 100~g groups. When moderate or greater reactogenicity (fever, headache, and injection site pain or erythema) after any vaccination is combined, 25%, 31%, 44%, and 88% of subjects reported events for the 0 ~g, 4 ~g, 20 I~g and 100 ~g groups, respectively. Neutralizing antibody data against l a pseudoparticles will be available. Immunogenicity data 2 weeks post 3rd vaccination is provided. Conclusion: This first-in-humans HCV E1E2/MF59C.1 vaccine was well-tolerated and produced significant antibody, lymphocyte proliferation and cytokine responses two weeks post third vaccination. Immunogenicitydata two weekspost 3rd vaccination Group 0~g Anti-HCV E1E2 Responders/total.n (%) 0/9 (0) GMT [CI] 5 [-.-]
4~g
20~g
100~g
14/14 (100) 14/14 (100) 16/16 (100) 372.7 795.4 423.4 [246.2.564.2] [499.3.1267.2] [216.8.826.7]
CD81 neutralizationof bindingantibody Responders/total.n (%) 0/7 (0) 7/10 (70) 9/11 (82) 10/12(83) GMT [CI] 2.52 48.89 99.25 99.93 [1.1.5.8] [25.3.94.5] [34.9,2982.0] [28.2,353.8] E1E2 inducedlymphoproliferation RespondersFi-otal.n (%) 0/9 (0) 14/14 (100) 13/14 (93) 16/16 (100) GMSI [Cl] 1.1 [0.9,1.3] 55.9 [35.2,88.6] 32.4 [17.4,60.4] 14.0 [9.0,21.8] Cytokineexpression,mean(SD)concentration,pg/mL IFN-gamma 7.3(11.8) ND ND 205.8(512.5) IL-2 0.5(0.0) ND ND 48.8(127.1) ILJ, 1.5(1.8) ND ND 4.5(4.2) IL-10 1.5(1.7) ND ND 66.2(67.8)
I-0-.-~
Towards effective prophylactic and therapeutic vaccination against HCV
A. Folgori*. IRBM P. Angeletti, Via Pontina Km 30.600, 00040,
Pomezia, Italy HCV is the leading cause of chronic liver disease in the world with approximately 123 million people chronically infected by the virus. Incident rates are still significant in the developed world and there is a large pool of undiagnosed HCV-infected individuals. In the developing world, the HCV epidemic remains unabated, primarily due to lack of routine blood screening. As with many other infectious diseases, a significant epidemiologic impact on the spread of HCV infection will only be achieved subsequent to the development and introduction of an effective vaccine. Cellular immune responses are deemed essential for spontaneous resolution of acute hepatitis C and long-term protection in humans and chimpanzees, indicating that a vaccine capable of inducing a potent and broad T-cell-mediated immunity (CMI) could protect from chronic infection. Such a vaccine might also be used in a therapeutic setting, as acutely infected individuals with chronic evolution display low and transient CMI. Thus, restoration of potent, durable and broadly reactive T-cell immunity by a therapeutic vaccine may achieve viral clearance.
$5 A novel approach toward an effective T-cell based vaccine against HCV has been recently proposed, which is based on genetic vaccine vectors. For this purpose DNA and Modified Vaccinia Ankara (MVA) vectors have been evaluated in a number of pre-clinical models. We have developed a number of non cross-reactive replication defective Adenoviral vectors encoding for the 2000 amino acid-long HCV Non Structural Region from a l b isolate (NS). These vectors were shown to elicit extremely potent CD4 + and CD8 + T-cell responses in rodents and primates. Recently, a proof of concept vaccination and heterologous challenge experiment was conducted in chimpanzees. Potent, broad and long-lived T-cell responses to HCV were elicited in vaccinated animals using a prime/boost regimen with Adenoviral vector and electroporated plasmid DNA encoding for the NS region. Unlike previous approaches, the vaccine protected against acute and chronic disease induced by challenge with a high dose of a heterologous HCV strain. Rapid decline of circulating virus in vaccinated chimpanzees occurred as a result of massive expansion of vaccine-induced peripheral and intra-hepatic HCV-specific CD8 + T lymphocytes that cross-reacted with vaccine and virus epitopes. These findings suggest that the present HCV vaccine candidate has the potential to protect humans from HCV by first lowering viral replication at least hundred fold during the onset of infection and subsequently eradicating the virus, thus preventing establishment of chronic hepatitis.
PS03 - HBV: Animal and cellular models
(Sunday, July 2, 2006, 11:00-12:30)
[•..•
Primary and secondary occult hepadnaviral infections: identification and differential characteristics
T.I. Michalak*, RM. Mulrooney-Cousins, C.S. Coffin, T.N.Q. Pham, S.A. Gujar. Molecular Virology and Hepatology Research, Faculty
of Medicine, Memorial University, St. John's, Canada Background and Objectives: The existence of occult infections with HBV and related hepadnaviruses is now accepted. It is also evident that hepadnaviruses replicate in the host's lymphatic system. Studies of the natural animal models of hepatitis B, particularly woodchucks infected with woodchuck hepatitis virus (WHV), significantly contributed to identification and to delineation of the characteristics of serologically silent hepadnaviral persistence. Our studies revealed the existence of two distinctive forms, designated as primary occult (POI) and secondary occult (SOl) infection. Here, we solidify the criteria for their diagnosis. Methods: Woodchucks were intravenously infected with - 1 0 to 1010 WHV virions. Serial sera, PBMC and liver biopsies, as well as autopsy liver and lymphatic organ were analyzed from the animals which developed serologically silent infection, self-limited acute hepatitis or chronic hepatitis. Serum WHsAg, anti-WHs and antiWHc were determined by routine immunoassays. WHV DNA and cccDNA detected by highly sensitive PCR-based assays verified by nucleic acid hybridizations. WHV-specific T cell responses were measured by CFSE-flow cytometry. Liver alterations were assessed by histology. Results: Virus doses below or equal to 103 virions induced serologically silent, but WHV DNA reactive POI, in which virus replication occurred in lymphatic organs and PBMC, but not in the liver. Liver histology remained normal. In some cases, the liver became WHV infected with time and displayed minimal inflammatory alterations or no histological changes. Remarkably, virus-specific T cell proliferative, but not humoral immune responses were evident during POI. Doses greater than 103 virions induced serum WHsAg and anti-WHc-positive infection with acute hepatitis, which occasionally progressed to serum WHsAg-positive chronic infection. Resolution of acute infection was followed by SOl with life-long persistence of low level WHV DNA and anti-WHc in circulation and WHV replication in both the lymphatic system and the liver. Liver histology showed protracted minimal inflammation with periods of normal morphology. However, HCC developed in -20% of cases. Virus-specific T cell responses persisted for life during SOl. It was also established that
[0~A
phase 1 trial of a novel E1E2/MF59C.1 hepatitis C vaccine candidate in healthy HCV-negative adults (DMID 01-002)
S E Frey 1., G J Gorse 1, A M DiBisceglie 1, D Rosa 2, Z Stamataki 3, J McKeating 3, R Ray 1, S Coates 2, V Schultze 4, S Abrignan 2, M Houghton 2, H Hill 5, R B Belshe 1 1/nterna/
Medicine, Saint Louis University, St. Louis; 2Chiron Corporation, Emeryville, USA, 3Div of Immunity and Infection, Birmingham Univ., Birmingham, United Kingdom, 4Chiron Vaccines, Marburg, Germany, 5The EMMES Corporation, Rockville, USA Background and Objectives: HCV remains a serious world-wide public health problem. To date there is no effective vaccine or therapy. A dose escalation study of HCV E1 E2/MF59C.1 adjuvanted vaccine was conducted to evaluate safety and immunogenicity. Methods: Healthy adults were randomized equally to 3 groups (16 vaccine and 4 placebo recipients). Vaccines were given at 0, 4, 24 and 48 weeks. Results: Sixty subjects ages 18 to 45 were enrolled. Sixty, 55, 52 and 50 subjects received 1, 2, 3, and 4 vaccines in the 01~g, 41~g, 20~g and 100~g groups. When moderate or greater reactogenicity (fever, headache, and injection site pain or erythema) after any vaccination is combined, 25%, 31%, 44%, and 88% of subjects reported events for the 0 ~g, 4 ~g, 20 I~g and 100 ~g groups, respectively. Neutralizing antibody data against l a pseudoparticles will be available. Immunogenicity data 2 weeks post 3rd vaccination is provided. Conclusion: This first-in-humans HCV E1E2/MF59C.1 vaccine was well-tolerated and produced significant antibody, lymphocyte proliferation and cytokine responses two weeks post third vaccination. Immunogenicitydata two weekspost 3rd vaccination Group 0~g Anti-HCV E1E2 Responders/total.n (%) 0/9 (0) GMT [CI] 5 [-.-]
4~g
20~g
100~g
14/14 (100) 14/14 (100) 16/16 (100) 372.7 795.4 423.4 [246.2.564.2] [499.3.1267.2] [216.8.826.7]
CD81 neutralizationof bindingantibody Responders/total.n (%) 0/7 (0) 7/10 (70) 9/11 (82) 10/12(83) GMT [CI] 2.52 48.89 99.25 99.93 [1.1.5.8] [25.3.94.5] [34.9,2982.0] [28.2,353.8] E1E2 inducedlymphoproliferation RespondersFi-otal.n (%) 0/9 (0) 14/14 (100) 13/14 (93) 16/16 (100) GMSI [Cl] 1.1 [0.9,1.3] 55.9 [35.2,88.6] 32.4 [17.4,60.4] 14.0 [9.0,21.8] Cytokineexpression,mean(SD)concentration,pg/mL IFN-gamma 7.3(11.8) ND ND 205.8(512.5) IL-2 0.5(0.0) ND ND 48.8(127.1) ILJ, 1.5(1.8) ND ND 4.5(4.2) IL-10 1.5(1.7) ND ND 66.2(67.8)
I-0-.-~
Towards effective prophylactic and therapeutic vaccination against HCV
A. Folgori*. IRBM P. Angeletti, Via Pontina Km 30.600, 00040,
Pomezia, Italy HCV is the leading cause of chronic liver disease in the world with approximately 123 million people chronically infected by the virus. Incident rates are still significant in the developed world and there is a large pool of undiagnosed HCV-infected individuals. In the developing world, the HCV epidemic remains unabated, primarily due to lack of routine blood screening. As with many other infectious diseases, a significant epidemiologic impact on the spread of HCV infection will only be achieved subsequent to the development and introduction of an effective vaccine. Cellular immune responses are deemed essential for spontaneous resolution of acute hepatitis C and long-term protection in humans and chimpanzees, indicating that a vaccine capable of inducing a potent and broad T-cell-mediated immunity (CMI) could protect from chronic infection. Such a vaccine might also be used in a therapeutic setting, as acutely infected individuals with chronic evolution display low and transient CMI. Thus, restoration of potent, durable and broadly reactive T-cell immunity by a therapeutic vaccine may achieve viral clearance.
$5 A novel approach toward an effective T-cell based vaccine against HCV has been recently proposed, which is based on genetic vaccine vectors. For this purpose DNA and Modified Vaccinia Ankara (MVA) vectors have been evaluated in a number of pre-clinical models. We have developed a number of non cross-reactive replication defective Adenoviral vectors encoding for the 2000 amino acid-long HCV Non Structural Region from a l b isolate (NS). These vectors were shown to elicit extremely potent CD4 + and CD8 + T-cell responses in rodents and primates. Recently, a proof of concept vaccination and heterologous challenge experiment was conducted in chimpanzees. Potent, broad and long-lived T-cell responses to HCV were elicited in vaccinated animals using a prime/boost regimen with Adenoviral vector and electroporated plasmid DNA encoding for the NS region. Unlike previous approaches, the vaccine protected against acute and chronic disease induced by challenge with a high dose of a heterologous HCV strain. Rapid decline of circulating virus in vaccinated chimpanzees occurred as a result of massive expansion of vaccine-induced peripheral and intra-hepatic HCV-specific CD8 + T lymphocytes that cross-reacted with vaccine and virus epitopes. These findings suggest that the present HCV vaccine candidate has the potential to protect humans from HCV by first lowering viral replication at least hundred fold during the onset of infection and subsequently eradicating the virus, thus preventing establishment of chronic hepatitis.
PS03 - HBV: Animal and cellular models
(Sunday, July 2, 2006, 11:00-12:30)
[•..•
Primary and secondary occult hepadnaviral infections: identification and differential characteristics
T.I. Michalak*, RM. Mulrooney-Cousins, C.S. Coffin, T.N.Q. Pham, S.A. Gujar. Molecular Virology and Hepatology Research, Faculty
of Medicine, Memorial University, St. John's, Canada Background and Objectives: The existence of occult infections with HBV and related hepadnaviruses is now accepted. It is also evident that hepadnaviruses replicate in the host's lymphatic system. Studies of the natural animal models of hepatitis B, particularly woodchucks infected with woodchuck hepatitis virus (WHV), significantly contributed to identification and to delineation of the characteristics of serologically silent hepadnaviral persistence. Our studies revealed the existence of two distinctive forms, designated as primary occult (POI) and secondary occult (SOl) infection. Here, we solidify the criteria for their diagnosis. Methods: Woodchucks were intravenously infected with - 1 0 to 1010 WHV virions. Serial sera, PBMC and liver biopsies, as well as autopsy liver and lymphatic organ were analyzed from the animals which developed serologically silent infection, self-limited acute hepatitis or chronic hepatitis. Serum WHsAg, anti-WHs and antiWHc were determined by routine immunoassays. WHV DNA and cccDNA detected by highly sensitive PCR-based assays verified by nucleic acid hybridizations. WHV-specific T cell responses were measured by CFSE-flow cytometry. Liver alterations were assessed by histology. Results: Virus doses below or equal to 103 virions induced serologically silent, but WHV DNA reactive POI, in which virus replication occurred in lymphatic organs and PBMC, but not in the liver. Liver histology remained normal. In some cases, the liver became WHV infected with time and displayed minimal inflammatory alterations or no histological changes. Remarkably, virus-specific T cell proliferative, but not humoral immune responses were evident during POI. Doses greater than 103 virions induced serum WHsAg and anti-WHc-positive infection with acute hepatitis, which occasionally progressed to serum WHsAg-positive chronic infection. Resolution of acute infection was followed by SOl with life-long persistence of low level WHV DNA and anti-WHc in circulation and WHV replication in both the lymphatic system and the liver. Liver histology showed protracted minimal inflammation with periods of normal morphology. However, HCC developed in -20% of cases. Virus-specific T cell responses persisted for life during SOl. It was also established that