51
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Affiliation(s)
- F Schödel
- Max-Planck-Institut für Biochemie, Martinsried, Germany
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52
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Abstract
The currently licensed parenteral cholera vaccine has not been a useful public health tool in the control of cholera. Building on the knowledge that primary infection offers significant protection against reinfection and that mucosal immunity mediates this protection, several oral cholera vaccines have been developed. These vaccine candidates or future candidates derived using the techniques of molecular biology will no doubt contribute to the control of cholera.
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53
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O'Hagan DT. Oral delivery of vaccines. Formulation and clinical pharmacokinetic considerations. Clin Pharmacokinet 1992; 22:1-10. [PMID: 1559304 DOI: 10.2165/00003088-199222010-00001] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
MESH Headings
- Administration, Oral
- Animals
- Bacterial Infections/prevention & control
- Bacterial Vaccines/administration & dosage
- Bacterial Vaccines/immunology
- Bacterial Vaccines/pharmacokinetics
- Drug Carriers
- Humans
- Immunoglobulin A, Secretory/immunology
- Mouth Mucosa/immunology
- Vaccination/methods
- Vaccines, Attenuated/administration & dosage
- Vaccines, Attenuated/immunology
- Vaccines, Attenuated/pharmacokinetics
- Vaccines, Inactivated/administration & dosage
- Vaccines, Inactivated/immunology
- Vaccines, Inactivated/pharmacokinetics
- Vaccines, Synthetic/administration & dosage
- Vaccines, Synthetic/immunology
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Affiliation(s)
- D T O'Hagan
- Department of Pharmaceutical Sciences, University of Nottingham, England
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54
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Tacket CO, Hone DM, Losonsky GA, Guers L, Edelman R, Levine MM. Clinical acceptability and immunogenicity of CVD 908 Salmonella typhi vaccine strain. Vaccine 1992; 10:443-6. [PMID: 1609547 DOI: 10.1016/0264-410x(92)90392-w] [Citation(s) in RCA: 114] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
An attenuated Salmonella typhi strain has been sought as an improved oral typhoid vaccine and as a carrier of protective antigens of other pathogens to make hybrid vaccines. Ideally, such a strain would be safe and induce protective immune responses after a single oral dose. CVD 908 is a mutant of S. typhi wild-type strain Ty2 with recombinant deletions in two genes, aroC and aroD. In phase 1 testing to date, this strain has not produced febrile responses or other significant adverse reactions in adult volunteers given doses of 5 x 10(4) to 5 x 10(7) organisms with sodium bicarbonate. In addition, after just a single oral dose of 5 x 10(7) colony-forming units, this strain induced IgG seroconversion to S. typhi lipopolysaccharide in 83% of vaccinees and stimulated specific IgA-secreting gut-derived lymphocytes in 100% of vaccinees. CVD 908 is a new oral typhoid vaccine that should be further investigated as a carrier for expressing foreign antigens in recombinant vaccine constructs.
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Affiliation(s)
- C O Tacket
- Department of Medicine, University of Maryland School of Medicine, Baltimore 21201
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55
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Neutra MR, Kraehenbuhl JP. M cell-mediated antigen transport and monoclonal IgA antibodies for mucosal immune protection. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1992; 327:143-50. [PMID: 1295335 DOI: 10.1007/978-1-4615-3410-5_16] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- M R Neutra
- Harvard Medical School, Children's Hospital, Boston, MA 02115
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56
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Murphy JR, Grez L, Schlesinger L, Ferreccio C, Baqar S, Muñoz C, Wasserman SS, Losonsky G, Olson JG, Levine MM. Immunogenicity of Salmonella typhi Ty21a vaccine for young children. Infect Immun 1991; 59:4291-3. [PMID: 1937790 PMCID: PMC259034 DOI: 10.1128/iai.59.11.4291-4293.1991] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
An attenuated Salmonella typhi Ty21a vaccine was administered to 18 infants and toddlers (less than or equal to 24 months old) to determine its safety and immunogenicity. The vaccination (10(9) CFU per dose, three doses) was well tolerated. However, after the vaccination there was no evidence of a humoral or cellular immune response to S. typhi. The vaccine used was known to be immunogenic for older children and adults. The results support the view that the immunogenicity of Ty21a is age dependent.
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Affiliation(s)
- J R Murphy
- Department of Medicine, University of Maryland School of Medicine, Baltimore 21201
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57
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Hormaeche CE. Live attenuated Salmonella vaccines and their potential as oral combined vaccines carrying heterologous antigens. J Immunol Methods 1991; 142:113-20. [PMID: 1919015 DOI: 10.1016/0022-1759(91)90298-t] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Live attenuated salmonellae are protective, and are candidate vaccines against invasive salmonella infections in man and animals. Different attenuating mutations have been described, and more than one can be incorporated in a vaccine for added safety. Combined salmonella vaccines express target carbohydrate and protein antigens or epitopes from viruses, bacteria and eukaryotic parasites, either within or on the surface of the cell, as capsules, fimbriae, or in the flagellin. Humoral, secretory and cellular responses to the recombinant antigens has been demonstrated. Experimental protection against diseases including streptococcal infection, tetanus, influenza and malaria has been obtained.
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58
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Affiliation(s)
- Marcus Hodge
- Communicable Diseases Section Department of Community Services and HealthCanberra
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59
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Attridge SR, Dearlove C, Beyer L, van den Bosch L, Howles A, Hackett J, Morona R, LaBrooy J, Rowley D. Characterization and immunogenicity of EX880, a Salmonella typhi Ty21a-based clone which produces Vibrio cholerae O antigen. Infect Immun 1991; 59:2279-84. [PMID: 1711014 PMCID: PMC258007 DOI: 10.1128/iai.59.7.2279-2284.1991] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
EX645 is a derivative of Salmonella typhi Ty21a which carries a plasmid specifying production of Vibrio cholerae O antigen. When cultured with exogenous galactose to overcome the galE defect of the vector, EX645 also synthesizes S. typhi O antigen, and this can result in the masking of the shorter V. cholerae O antigen on the bacterial surface. To determine whether the potential for such masking at least partly underlies the inconsistency of anti-V. cholerae responses elicited by EX645, a derivative of this strain has been isolated, characterized, and tested for immunogenicity in human volunteers. EX880 has an rfb defect which prevents synthesis of S. typhi O antigen, and consequently V. cholerae O antigen is still detectable on the surface of the clone following growth in the presence of galactose. Compared with EX645, EX880 more consistently elicited significant rises in serum bactericidal antibody levels, although individual responses within a cohort still varied widely.
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Affiliation(s)
- S R Attridge
- Enterovax Ltd., c/o Department of Microbiology and Immunology, University of Adelaide, Adelaide, Australia
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60
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Hall RH, Losonsky G, Silveira AP, Taylor RK, Mekalanos JJ, Witham ND, Levine MM. Immunogenicity of Vibrio cholerae O1 toxin-coregulated pili in experimental and clinical cholera. Infect Immun 1991; 59:2508-12. [PMID: 1711017 PMCID: PMC258041 DOI: 10.1128/iai.59.7.2508-2512.1991] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
A functional tcpA gene, encoding the major subunit of toxin-coregulated pili (TCP), is necessary for Vibrio cholerae O1 Ogawa strain 395 to colonize the human intestine and confer protective immunity to virulent challenge. The immunogenicity of TCP and other antigens in experimental and naturally acquired cholera was determined. Seroconversion to cholera toxin (CT), whole cell preparations, and to Ogawa lipopolysaccharide but not to purified native TCP or to a TcpA mimiotope was found in volunteers. Local intestinal secretory immunoglobulin A from volunteers showed conversions to cholera toxin and lipopolysaccharide but not to TCP. Cholera patients in Indonesia showed a seroconversion rate to TCP of 3 of 6 and a seroconversion to a TcpA mimiotope of 1 of 6. Volunteer and patient sera showed similar vibriocidal seroconversions when assayed against either TCP-positive and TCP-negative V. cholerae O1 strains, suggesting that TCP do not contribute demonstrably to the vibriocidal antigen. We conclude that although seroconversion to TCP can occur in naturally acquired cholera, solid long-term protection can be engendered in the absence of a detectable anti-TCP immune response.
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Affiliation(s)
- R H Hall
- Center for Vaccine Development, Division of Geographic Medicine, University of Maryland School of Medicine, Baltimore 21201
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61
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Forrest BD, LaBrooy JT. In vivo evidence of immunological masking of the Vibrio cholerae O antigen of a hybrid Salmonella typhi Ty21a-Vibrio cholerae oral vaccine in humans. Vaccine 1991; 9:515-20. [PMID: 1716810 DOI: 10.1016/0264-410x(91)90039-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The immunogenicity of the live oral hybrid vaccine organism Salmonella typhi Ty21a/V. cholerae Inaba (EX210) following its growth in media containing variable concentrations of supplemental galactose was examined in human volunteer subjects. The local intestinal IgA-specific antibody responses to both typhoid and cholera lipopolysaccharide (LPS) preparations were determined. It was observed that the immunogenicity of the galactose-independent Vibrio cholerae O antigen in vivo was dependent upon the variation in galactose-dependent long chain S. typhi O antigen production which was directly proportional to the media galactose concentration. It is likely that this observation was a result of steric hindrance of the presentation of the V. cholerae O antigen by S. typhi Ty21a in the presence of the longer, immunodominant S. typhi Ty21a O antigen. This observation may have relevance to the use of S. typhi vectors in vaccine development involving the presentation of LPS-associated heterologous antigens.
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Affiliation(s)
- B D Forrest
- University of Adelaide Department of Medicine, Royal Adelaide Hospital, South Australia
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62
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Abstract
Considerable progress has been made in the last decade in developing vaccines against the most important enteric infections. Two new, widely licensed vaccines (oral Ty21a and parenteral Vi) are available against typhoid fever, and new attenuated Salmonella typhi strains are ready for testing. An engineered live orally administered cholera vaccine, CVD 103-HgR, is undergoing clinical trials for safety, immunogenicity, and transmissibility in children in areas where cholera is endemic. Multiple candidate vaccines against rotavirus, Shigella, and enterotoxigenic Escherichia coli are in clinical trials. Newly acquired knowledge about pathogenesis and mucosal and cellular immunology, coupled with application of biotechnology, has already resulted in many candidates for vaccines, and more are expected to appear within the next few years.
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Affiliation(s)
- M M Levine
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore 21201
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63
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Specific immune response in the human respiratory tract following oral immunization with live typhoid vaccine. Infect Immun 1991; 59:1206-9. [PMID: 1997425 PMCID: PMC258392 DOI: 10.1128/iai.59.3.1206-1209.1991] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Specific antibody responses in the lower respiratory tract of human subjects to orally administered Salmonella typhi Ty21a are reported. These responses, predominantly of the immunoglobulin G class, were determined to be a transudate from serum. These results were supported by the similarity in responses to parenteral administration of heat-killed typhoid vaccine. Specific immunoglobulin A antibody was a poor contributor to the respiratory antibody response to either vaccine.
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64
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Brey RN, Bixler GS, Fulginiti JP, Dilts DA, Sabara MI. Oral delivery of antigens in live bacterial vectors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1991; 303:169-84. [PMID: 1725232 DOI: 10.1007/978-1-4684-6000-1_18] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- R N Brey
- Praxis Biologics, Rochester, New York 14623
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65
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Levine MM, Hone D, Tacket C, Ferreccio C, Cryz S. Clinical and field trials with attenuated Salmonella typhi as live oral vaccines and as "carrier" vaccines. Res Microbiol 1990; 141:807-16. [PMID: 2101470 DOI: 10.1016/0923-2508(90)90114-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In recent years there has been a resurgence of research to develop new and improved attenuated strains of Salmonella typhi to function as live oral vaccines against typhoid fever and to serve as "carrier" vaccines to express foreign antigens of other pathogens and deliver them to the immune system. Strain Ty21a has served as a prototype in clinical and field trials to identify the optimal formulations and dosage schedules for live vaccines and to quantitate the duration of protection that can be achieved. Clinical trials with three new attenuated S. typhi candidate vaccines, a Vi+ variant of Ty21a, an aroC,aroD double mutant recombinant strain and a cya,crp double mutant, are underway or will be initiated shortly.
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Affiliation(s)
- M M Levine
- Department of Medicine, University of Maryland School of Medicine, Baltimore 21201
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66
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Abstract
In summary, HIV vaccine studies described have generally not been designed to measure the effect of the adjuvant or to make comparisons between adjuvants. In only one study was a head-to-head comparison made between HIV antigen alone and antigen formulated with different adjuvants. We hope that future experiments with HIV/SIV vaccine candidates will be designed to determine the relative potency and safety of different adjuvants. Unfortunately, such experiments tend to be tedious and expensive. The design of these studies will need to address a number of variables which influence the response to the vaccine, including route and schedule of immunization, genotype and species of the vaccinated subject, and intrinsic characteristics of the antigen. In addition, the immunologic endpoints should include measurement of both B and T cell function. The carrier/adjuvant/antigen formulation should be hand-tailored and then standardized so that it is manufactured reproducibly without producing different biological effects between lots, and the vaccine formulation should be stable on storage and shipping. Finally, we obviously need to identify and test the protective antigen or antigens. The best adjuvant will never correct the choice of the wrong epitope.
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Affiliation(s)
- R Edelman
- Department of Medicine, University of Maryland School of Medicine, Baltimore 21201
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