Sabin Vaccine Strains Research Articles

Recombinants of Mahoney and Sabin strain poliovirus type 1: Analysis of In vitro phenotypic markers and evidence that resistance to guanidine maps in the nonstructural proteins

A neutralizing monoclonal antibody-resistant variant of the Sabin vaccine strain of poliovirus type 1 and a guanidine-resistant variant of the virulent parent Mahoney strain were derived. The two variants were used, in a coinfection, to generate recombinant virus containing both resistance markers. Recombinants appeared on the order of 1.0 PFU for every 10 4 total PFU. Two independently derived recombinant viruses were isolated. Each isolate contained the P1 (structural protein) gene region of the Sabin strain virus and the P3 (nonstructural replicase protein) gene region of the Mahoney strain virus. The recombinant virus phenotypes were compared with certain characteristic in vitro phenotypes of both parents. It was found that the slow growth in cell culture, temperature sensitivity, and virion surface charge characteristics of the Sabin virus mapped entirely to the structural protein gene region whereas the phenotype of the actinomycin D sensitivity of the Sabin virus mapped to the gene region specifying the nonstructural replication proteins. Sequence analysis of the recombinant RNA revealed that the crossover occurred 3′ of nucleotide 3919. This result showed that the resistance of poliovirus mutants to growth in 2 m M guanidine hydrochloride maps in the 3′-terminal region of the viral genome specifying the nonstructural proteins.

Comparison of the complete nucleotide sequences of the genomes of the neurovirulent poliovirus P3/Leon/37 and its attenuated Sabin vaccine derivative P3/Leon 12a1b.

As part of a study into the molecular basis of attenuation and reversion to neurovirulence in the Sabin poliovirus vaccines, we have determined the complete nucleotide sequence of a cloned DNA copy of the genome of P3/Leon/37, the neurovirulent progenitor of the type 3 Sabin vaccine strain, P3/Leon 12a1b. Comparison of the sequence with that which we previously obtained for the vaccine strain [Stanway, G., Cann, A. J., Hauptmann, R., Hughes, P., Clarke, L. D., Mountford, R. C., Minor, P. D., Schild, G. C. & Almond, J. W. (1983) Nucleic Acids Res. 11, 5629-5643] indicates that attenuation has been brought about by a maximum of 10 point mutations, at least 5 of which are likely to be of minor significance. Predicted amino acid sequences of all the known virus-encoded proteins show that amino acid substitutions have occurred at only three positions. Two of these are in structural proteins (i.e., Ser----Phe in VP3 and Lys----Arg in VP1), and the third, Thr----Ala, is in the nonstructural protein P2-3b. The distribution and nature of nucleotide and amino acid sequence differences suggest that a single base substitution may be responsible for the attenuated phenotype of the vaccine strain.

Natural variation of poliovirus neutralization epitopes.

Poliovirus-neutralizing monoclonal antibodies were prepared against type 1, type 2, and type 3 wild laboratory (Mahoney, MEF1, and Saukett) and Sabin vaccine strains. Fifty-five poliovirus laboratory strains and field isolates were assayed by neutralization index test with a panel of homotypic monoclonal antibodies. A total of 27 monoclonal antibodies were used. Two categories of neutralization epitopes were found, i.e., cross-reacting (K), which is present on almost all strains of the same serotype, and strain-specific (V, variable), either wild (VW) or Sabin (VS). Several distinct neutralization epitopes were defined for each of the three poliovirus serotypes in almost every category. The study of antigenic variation of the Sabin type 1 vaccine virus during replication in human intestine showed that the VS neutralization epitope may be lost and even replaced by the VW epitopes of the parental Mahoney virus. A late isolate from a vaccine-fed infant recovered the complete neutralization epitope pattern of the Mahoney strain. Upon in vivo virus replication, a different kind of antigenic variation was also detected in which an epitope lost its function in virus neutralization but kept its antigenic conformation unaltered. Neutralization epitope analysis demonstrated that the presence of VS epitopes on a field isolate suggests the Sabin origin of the strain when the isolate displays the same epitope pattern as the original Sabin virus, or confirms it when the VS epitope(s) is mutually exclusive of VW epitopes. The lack of VS epitopes on a field isolate does not rule out its being of Sabin origin.

Alteration in oligonucleotide fingerprint patterns of the viral genome in poliovirus type 2 isolated from paralytic patients.

A close relationship was demonstrated by oligonucleotide fingerprinting between genomes of the poliovirus type 2 Sabin vaccine strain and recent isolates from paralytic cases associated with vaccination in Japan. The oligonucleotide maps of isolates from an agammaglobulinemic patient, who continued to excrete poliovirus type 2 for 3.5 years after the administration of oral vaccine, showed that the genomic alteration proceeded gradually, retaining the majority of the oligonucleotides characteristic of the vaccine strain for a long period, indicating vaccine origin for the isolates. The final isolate at month 41, however, lost the majority of these oligonucleotides. The heterologous antigenic relationship between the final isolate and the previous isolates was also observed. The serial alteration in electrophoretic mobility of the major structural proteins (VP1, VP2, and VP3) was observed throughout the excreting period. These results indicate that the population of the virus in this individual changed markedly during the last short period (about 3 months), in which the treatment with secretory immunoglobulin A was carried out. Genome comparisons in oligonucleotide maps show that some oligonucleotides in the genome of the vaccine strain are highly mutable after passage in humans.

Identification of point mutations in the genome of the poliovirus sabin vaccine LSc 2ab, and catalogue of RNase T1- and RNase A-resistant oligonucleotides of poliovirus type 1 (Mahoney) RNA

Fingerprints have been prepared of RNase T1- and RNase A-resistant oligonucleotides of poliovirus type 1 (Mahoney) and its attenuated derivative, the Sabin vaccine strain LSc 2ab. Changes in the position of seven oligonucleotides have been observed and correlated by sequence analysis with transversions and transitions. Based on mapping procedures ( A. Nomoto, A. Jacobson, Y. F. Lee, J. J. Dunn, and Eckard Wimmer, 1979, J. Mol. Biol. 128, 179–196) and sequence studies ( N. Kitamura and E. Wimmer, 1980, Proc. Nat. Acad. Sci. USA 77, 3196–3200) the mutations have been localized within the viral genome. Assuming random distribution of the mutations our results imply that approximately 35 base changes may have occurred during attenuation of poliovirus type 1 (Mahoney). A catalogue of sequences of 55 RNase T1- and 16 RNase A-resistant oligonucleotides has been established.

Monoclonal antibodies to polioviruses. Production of specific monoclonal antibodies to the Sabin vaccine strains.

Murine lymphocyte hybridomas which produce neutralizing or non-neutralizing monoclonal antibodies to different type 1, 2 or 3 poliovirus strains were isolated. The majority of these monoclonal antibodies reacted with antigenic determinants present on different poliovirus strains of the same type. However, hybridomas producing monoclonal antibodies specific for each of the three Sabin vaccine strains were also generated.

The preparation of specific immune sera against type 3 poliovirus D-antigen and C-antigen and the demonstration of two C-antigenic components in vaccine strain populations.

Animals were immunized with purified D-antigen or C-antigen of type 3 poliovirus to produce specific antisera which were used to analyse the antigenic characteristics of the progeny virus in harvests from poliovirus type 3-infected cells. An examination of the virus progeny present at 24 h p.i. of cells with Sabin type 3 vaccine strain virus revealed a large population of particles sedimenting at a slightly lower rate (130S) than infectious virus (155S) in addition to slowly sedimenting (80S) empty capsids. Such 130S particles were not detected in the progeny from cells infected with strains genetically unrelated to the Sabin vaccine strains. They were non-infectious, contained RNA in an RNase-resistant form unless heated, and lacked the virion protein VP4. They expressed C-antigen rather than the D-antigen of infectious virus, and, therefore, had the properties previously described for poliovirus particles eluted from cells. The amount of incorporation of radio-isotope into the proteins or nucleic acids of such particles varied from 15 to 20% to 300% of the amount incorporated into infectious virus depending on the cells and virus strains studied. Virus strains genetically related to Sabin type 3 vaccine virus which were isolated from cases of paralytic poliomyelitis produced the particles in either low or undetectable quantities.

Comparative biochemical studies of type 3 poliovirus.

A study of the biochemistry of type 3 poliovirus strains which involves the examination of the virus-coded polypeptides in infected cells and the preparation of oligonucleotide maps is reported. The polypeptide patterns were shown to be a relatively stable property of virus strains and distinguished Sabin vaccine strains from wild strains of poliovirus type 3. This approach may be of value in deciding the origin (vaccine or nonvaccine) of field isolates of poliovirus. Oligonucleotide maps were found to be sensitive indicators of differences among strains and appear to form a basis for determining genetic relationships among strains. The nucleotide maps of two viruses isolated from human cases of paralytic poliomyelitis temporally associated with the administration of attenuated vaccine suggested a vaccine origin for the strain. In one case the nucleotide map was indistinguishable from that of the vaccine strain.

Genetic stability of Sabin strain of type 3 poliovirus in the sensitivity to inhibitory bovine serum. I. Selection of inhibitory bovine serum against type 3 Sabin strain and sensitivity to the serum of vaccine progenies.

Investigations were carried out on the identification and genetic stability of type 3 Sabin vaccine (Leon 12 a1b) strain using a bovine inhibitor marker.Sera with strong inhibitory activity to the virus were rarely found in calves, while with high frequencies in heifers, and found to be reduced slightly in number at advanced ages.Of 495 sera tested, two (BS-19 and BE-19) specifically neutralized 3 laboratory strains of type 3 poliovirus including Leon 12 a1b, and left wild virus strains of the same type entirely unaffected. The strain-specific reactivity of the inhibitory sera was clearly demonstrated in the kinetic neutralization test.In vitro or human passage progenies of the vaccine virus were investigated for their sensitivity to the two bovine sera. While both the vaccine virus and its progenies were equally sensitive to BS-19, the progenies were less sensitive than the original vaccine virus to the inhibition by BE-19.On the basis of these results, the practical utility of bovine inhibitor marker for the identification of vaccine-derived viruses was discussed.

Antigenic segregation of type 3 poliovirus isolates related and unrelated to Sabin's vaccine strain with the use of modified Wecker and McBride techniques.

Antigenic segregation of type 3 poliovirus isolates related and unrelated to Sabin's vaccine strain with the use of modified Wecker and McBride techniques.

PERSISTENCE OF ANTIBODY AFTER ORAL TRIVALENT POLIOVIRUS VACCINE (SABIN STRAINS).

BECAUSE of the favorable rates of serum-antibody conversion obtained in a pilot study in Elkins, West Virginia, with two feedings of a trivalent oral poliovirus vaccine,1 the same vaccine was used in a mass vaccination program in Hillsborough County, Florida, in the early spring of 1962.2 In the Hillsborough County program 5 different lots of the trivalent vaccine were used. They represented mixtures of 5 consecutive lots of monovalent vaccine of each poliovirus type prepared from the Sabin vaccine strains by Lederle Laboratories in compliance with vaccine-licensing requirements.3 All 15 monovalent lots had passed all the prescribed tests, including . . .

The use of a modified Wecker technique for the serodifferentiation of type 1 polioviruses related and unrelated to Sabin's vaccine strain. I. Standardization and evaluation of the test.

The use of a modified Wecker technique for the serodifferentiation of type 1 polioviruses related and unrelated to Sabin's vaccine strain. I. Standardization and evaluation of the test.