“…It is known that the type 2 component of Sabin IPV is less immunogenic than the wild type 2 strain in classical IPV [6], an observation that has not been explained in a satisfactory way. It was therefore necessary to investigate the immunogenicity of empty capsids (or VLPs) of the stabilised strains to compare them to classical IPV.…”
Section: Resultsmentioning
confidence: 99%
“…This will include IPV production where colossal amounts of virus are grown and subsequently inactivated with formalin; the strains in current use are mainly wild types known to be able to cause poliomyelitis in humans, although two companies have licensed products based on the live attenuated Sabin strains used in OPV. Safe production of IPV is essential and one way to do this is to devise viable production strains that are intrinsically safer [6, 7, 8]. An alternative described here involves production of empty viral particles with the correct antigenic and immunogenic properties which could be expressed by recombinant technology and not involve infectious virus at any stage.…”
While wild type polio has been nearly eradicated there will be a need to continue immunisation programmes for some time because of the possibility of re-emergence and the existence of long term excreters of poliovirus. All vaccines in current use depend on growth of virus and most of the non-replicating (inactivated) vaccines involve wild type viruses known to cause poliomyelitis. The attenuated vaccine strains involved in the eradication programme have been used to develop new inactivated vaccines as production is thought safer. However it is known that the Sabin vaccine strains are genetically unstable and can revert to a virulent transmissible form. A possible solution to the need for virus growth would be to generate empty viral capsids by recombinant technology, but hitherto such particles are so unstable as to be unusable. We report here the genetic manipulation of the virus to generate stable empty capsids for all three serotypes. The particles are shown to be extremely stable and to generate high levels of protective antibodies in animal models.
“…It is known that the type 2 component of Sabin IPV is less immunogenic than the wild type 2 strain in classical IPV [6], an observation that has not been explained in a satisfactory way. It was therefore necessary to investigate the immunogenicity of empty capsids (or VLPs) of the stabilised strains to compare them to classical IPV.…”
Section: Resultsmentioning
confidence: 99%
“…This will include IPV production where colossal amounts of virus are grown and subsequently inactivated with formalin; the strains in current use are mainly wild types known to be able to cause poliomyelitis in humans, although two companies have licensed products based on the live attenuated Sabin strains used in OPV. Safe production of IPV is essential and one way to do this is to devise viable production strains that are intrinsically safer [6, 7, 8]. An alternative described here involves production of empty viral particles with the correct antigenic and immunogenic properties which could be expressed by recombinant technology and not involve infectious virus at any stage.…”
While wild type polio has been nearly eradicated there will be a need to continue immunisation programmes for some time because of the possibility of re-emergence and the existence of long term excreters of poliovirus. All vaccines in current use depend on growth of virus and most of the non-replicating (inactivated) vaccines involve wild type viruses known to cause poliomyelitis. The attenuated vaccine strains involved in the eradication programme have been used to develop new inactivated vaccines as production is thought safer. However it is known that the Sabin vaccine strains are genetically unstable and can revert to a virulent transmissible form. A possible solution to the need for virus growth would be to generate empty viral capsids by recombinant technology, but hitherto such particles are so unstable as to be unusable. We report here the genetic manipulation of the virus to generate stable empty capsids for all three serotypes. The particles are shown to be extremely stable and to generate high levels of protective antibodies in animal models.
“…[1] This program had led to a dramatic decline in polio cases, with no polio infections from wild strains reported in Japan since 1980. [2] However, OPV is associated with rare cases of vaccine-associated paralytic poliomyelitis (VAPP). VAPP can occur in recently vaccinated individuals or in susceptible individuals indirectly exposed to vaccine virus, as can occur in close contacts of vaccinated individuals.…”
Section: Introductionmentioning
confidence: 99%
“…[5] As no polio infection from wild strains had been reported for several decades in Japan, public concern regarding VAPP cases was increasing. [2,4] …”
Section: Introductionmentioning
confidence: 99%
“…As an alternative, Japan has implemented a new polio vaccination program with 4 doses (i.e., 3 doses to prime immunity and 1 booster dose) of inactivated monovalent polio vaccine (IPV) or quadrivalent vaccine against diphtheria, pertussis, and tetanus with IPV (DTaP-IPV). [2] …”
In Japan, the routine immunization program with oral polio vaccine (OPV) has been suspended since September 2012, when a program with 4 doses of inactivated monovalent polio vaccine (IPV) or quadrivalent vaccine against diphtheria, pertussis, and tetanus with IPV (DTaP-IPV) was introduced. The aim of this study was to examine the interchangeability among these 3 types of polio vaccines.We conducted a prospective cohort study at 5 pediatric clinics in Japan. A total of 153 infants were assigned to 1 of the 4 groups by considering the vaccination history of OPV and trivalent vaccine against DTaP. Eleven infants with a history of OPV received 3 doses of DTaP-IPV; 49 infants with a history of OPV and DTaP received 3 doses of IPV; 50 polio vaccine-naïve infants received 2 doses of IPV followed by 2 doses of DTaP-IPV; and 43 polio vaccine-naive infants received 2 doses of DTaP-IPV followed by IPV. The immunogenicity after polio vaccination was evaluated among these 4 groups.After 2 doses of polio vaccination, more than 80% of the infants exhibited a neutralization antibody titer ≥1:8 for all Sabin strains and wild strains in all groups. After the third dose, the seroprotection proportion (i.e., a neutralization antibody titer ≥1:8) reached about 100%. After the fourth dose, a neutralization antibody titer exceeded the required protective levels (i.e., a neutralization antibody titer ≥1:8) considerably in all groups.Four doses of polio vaccines induced a sufficient level of immunity in Japanese infants, irrespective of vaccine combinations or order.
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