Genetic composition of a high-yielding influenza A virus recombinant: a vaccine strain against "Swine" influenza.

Analysis of the RNA migration pattern of a high-yielding influenza virus recombinant, X-53, used in vaccine production, reveals that only the two genes coding for hemagglutinin and neuraminidase antigens were derived from the "swine" influenza virus parent. A/New Jersey/11/76, while six were acquired from the A/PR/8/34 (HON1) parent, donor of the high yield characteristic.

Characterization of a naturally occurring diamine auxotroph of Veillonella alcalescens.

Veillonella alcalescens strain ATCC 17745 was shown to require putrescine or cadaverine for growth. None of the other compounds tried, including magnesium and spermidine, were able to substitute for the diamines. Studies with labeled diamines showed that spermidine was made from putrescine in this organism. A polyamine analogous to spermidine, but made from cadaverine, was not found. A combination of growth experiments and chemical assays suggested that protein synthesis was limited in diamine-starved cells. Protein synthesis occurred prior to nucleic acid synthesis when putrescine was added to starved cells.

Polyacrylamide gel electrophoresis of the RNAs of new influenza virus strains: an epidemiological tool.

Recently, we have shown by separating the RNAs and proteins of different influenza A viruses on polyacrylamide gels, that influenza A viruses contain 8 genes corresponding to 8 virus specific proteins. By analyzing the RNA patterns and the protein patterns of different recombinant viruses we, subsequently, succeeded in establishing a complete genetic map for influenza A viruses. These techniques were extended to characterize the genome of new influenza virus isolates. Thus it was found that the human isolate A/Wi/263/76 and the two swine virus isolates, A/swine/Wi/49/76 and A/swine/Wi/50/76 possess identical RNA patterns, which differ from the RNA patterns of other recent swine virus isolates. The human (Wi/263) and the two animal isolates (Wi/49 and Wi/50) were obtained on the same farm suggesting that the animal virus was transmitted from swine to man. This proves that swine viruses may occasionally infect humans without causing a pandemic. A comparative analysis of the different RNA patterns of other swine influenza viruses isolated around the same time at different locations and of those of recent human isolates showed that our polyacrylamide gel technique is a valuable epidemiological tool to identify and and characterize different influenza virus isolates.

Identification of the defective genes in three mutant groups of influenza virus.

Seven complementation-recombination groups of temperature-sensitive (ts) influenza WSN virus mutants have been previously isolated. Recently two of these groups (IV and VI) were shown to possess defects in the neuraminidase and the hemagglutinin gene, respectively, and two groups (I and III) were reported to have defects in the P3 and P1 proteins which are required for complementary RNA synthesis. In this communication we report on the defects in the remaining three mutant groups. Wild-type (ts+) recombinants derived from ts mutants and different non-ts influenza viruses were analyzed on RNA polyacrylamide gels. This technique permitted the identification of the P2 protein, the nucleoprotein, and the M protein as the defective gene products in mutant groups II, V, and VII, respectively. Based on the physiological behavior of mutants in groups II and V, it appears that P2 protein and nucleoprotein are required for virion RNA synthesis during influenza virus replication.

RNAs of influenza A, B, and C viruses.

The nucleic acids of influenza A, B, and C viruses were compared. Susceptibility to nucleases demonstrates that influenza C virus, just as influenza A and B viruses, possesses single-stranded RNA as its genome. The base compositions of the RNAs of influenza A, B, and influenza C virus are almost identical and comparative analysis on polyacrylamide gels shows that the genome of influenza C/GL/1167/54 virus, like that of the RNAs of influenza A and B viruses, is segmented. Eight distinct RNA bands were found for influenza A/PR/8/34 virus and for influenza B/Lee/40 virus. The RNA of influenza C/GL/1167/54 virus separated into at least four segments. The total molecular weights of the RNA of influenza A/PR/8/34 and B/Lee/40 virus were calculated to be 5.29 X 10(6) and 6.43 X 10(6), respectively. A minimum value of 4.67 X 10(6) daltons was obtained for influenza C/GL/1167/54 virus RNA. The data suggest that influenza C viruses are true members of the influenza virus group.

Mapping of the influenza virus genome. III. Identification of genes coding for nucleoprotein, membrane protein, and nonstructural protein.

In previous communications we reported that the eight RNA segments of influenza A/PR/8/34 (HON1) virus could be distinguished from corresponding segments of influenza A/Hong Kong/8/68 (H3N2) virus by migration on polyacrylamide-urea gels. Examination of the RNA patterns of the two parent viruses and recombinants derived from them in concert with serological identification of surface proteins and analysis of the other proteins on sodium dodecyl sulfate gradient gels permitted the identification of the genes coding for hemagglutinin, neuraminidase, and the P1, P2, and P3 proteins (Palese and Schulman, 1976; P. Palese et al., Virology, in press). In the present report we have extended these observations using similar techniques to examine other recombinants and have identified the genes coding for the remaining virus-specific moving RNA segment as 1) and segment 6 of Hong Kong virus coding for the respective nucleoproteins, and that segment 7 of both viruses codes for the membtane protein and RNA segment 8 codes for the nonstructural protein. This completes the mapping of the influenza A virus genome.

P1 and P3 proteins of influenza virus are required for complementary RNA synthesis.

Members of two temperature-sensitive (ts) mutant groups of influenza A/WSN virus defective in complementary RNA synthesis were analyzed with respect to the identity of their defective genes. RNA analysis of recombinants having a ts+ phenotype derived from the mutants and HK virus permitted the identification of RNA 1 and RNA 2 as the single defective gene in mutant groups I and III, respectively. Based on knowledge obtained by mapping the WSN virus genome, it then was possible to determine that biologically functional P3 protein (coded for by RNA 1) and P1 protein (RNA 2) are required for complementary RNA synthesis of influenza virus.

Antibody responses after immunization with polyvalent pneumococcal vaccine containing 10, 25, or 50 micrograms of 14 polysaccharide types per dose.

Immune responses were determined to three different doses of a pneumococcal vaccine which contained 10, 25, or 50 micrograms of 14 polysaccharide types (1, 3, 4, 6A, 6B, 7F, 8, 9N, 12F, 14, 18C, 19F, 20, and 23F) per dose. Pre- and 4-weeks postvaccination sera were examined by radioimmunoassay. Ratios of geometric mean titers (GMT) showed a greater than threefold increase of antibodies to each type of polysaccharide regardless of the dose of antigen. The post-GMT was highest to 12 of 14 types in recipients of the 25-micrograms vaccine. Subjects in the group receiving a 25-micrograms dose of each antigen showed more two- and fourfold titer increases than did subjects in the group receiving 10- and 50-micrograms doses, but, in general, seroconversion rates were similar in all the groups. All GMT values in the 25-micrograms vaccine group were well above what is currently considered to be the protective level of antibody. Local reactions, overall, were low in all groups. Pain, induration, and tenderness at the site of injection, which were greatest in recipients of the 50-micrograms dose/antigen, were progressively lower with the 25- and 10-micrograms dose/antigen.

Common sequence at the 5' ends of the segmented RNA genomes of influenza A and B viruses.

Guanylyl- and methyltransferases, isolated from purified vaccinia virus, were used to specifically label the 5' ends of the genome RNAs of influenza A and B viruses. All eight segments were labeled with [alpha-(32)P]guanosine 5'-triphosphate or S-adenosyl[methyl-(3)H]methionine to form "cap" structures of the type m(7)G(5')pppN(m)-, of which unmethylated (p)ppN- represents the original 5' end. Further analyses indicated that m(7)G(5')pppA(m), m(7)G(5')pppA(m)pGp, and m(7)G(5')pppA(m)pGpUp were released from total and individual labeled RNA segments by digestion with nuclease P1, RNase T1, and RNase A, respectively. Consequently, the 5'-terminal sequences of most or all individual genome RNAs of influenza A and B viruses were deduced to be (p)ppApGpUp. The presence of identical sequences at the ends of RNA segments of both types of influenza viruses indicates that they have been specifically conserved during evolution.

Characterization of Vero cells.

A cell line used in the production of biologicals should be free of infectious agents, and 'described with respect to cytogenetic characteristics and tumorigenicity'. Vero, a continuous cell line derived from a normal African green monkey kidney, was examined for the presence of retroviruses and for tumorigenic potential. We were unable to detect the presence of retroviruses by reverse transcriptase assay, electron microscopy or hybridization of cellular genomic DNA with Mason-Pfizer monkey virus DNA probes. In addition, passage 156 Vero cells did not form progressively growing tumors in nude mice or grow with high efficiency in soft agarose.

Oral poliovirus vaccine in the United States: molecular characterization of Sabin type 3 after replication in the gut of vaccinees.

Derivatives of Sabin 3 shed from recipients of oral poliovirus vaccine in the United States (U.S.) were examined for genetic changes identified in strains excreted by vaccinees in the United Kingdom [U.K.; Evans et al., 1985; Cammack et al., 1988, Macadam et al., 1989]. Among the eight primary vaccinees studied, the duration of excretion and molecular evolution of type 3 strains varied greatly. The period of virus excretion after vaccination ranged from as few as 2 days to as many as 36 days. Nucleotide sequence analysis of viral RNAs extracted from shed virus indicated that only fifty percent of the vaccinees exclusively excreted strains in which the attenuating mutation at nucleotide 472 in the 5' noncoding region of the genome had reverted from uracil (U) to cytosine (C), the nucleotide found in neurovirulent strains. Compared to the wild-type Leon strain, the low activity of stool isolate KW4 in a complete monkey neurovirulence test demonstrated that presence of C at 472 does not render a type 3 strain pathogenic. Conversely, an isolate was identified which efficiently replicated in monkey nervous tissue and maintained the attenuated U at 472. Oligonucleotide fingerprinting and sequence analysis of viral RNAs from stool isolates indicated that one vaccinee (KW) eventually excreted intertypic recombinant strains consistent with those reported in the U.K. studies. Unique to this study, one vaccinee (KS) excreted nonrecombinant virus possessing U at 472 for up to 21 days. The significance of the KS strain profile in relation to differences in the U.S. vaccine compared to the vaccine distributed in the U.K. and other countries is discussed.