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Biomedical subjects

J F Obijeski

Publications and source records attributed to J F Obijeski.

At least 19 recordsLinked to original sources
PubMed1996

Protection of MN-rgp120-immunized chimpanzees from heterologous infection with a primary isolate of human immunodeficiency virus type 1.

Three chimpanzees immunized with recombinant gp120 from human immunodeficiency virus type 1 (HIV-1) strain MN and 1 control animal were challenged intravenously with a primary isolate of HIV-1SF2. Viral infection was detected in the control animal by viral culture, polymerase chain reaction, and multiple serologic assays beginning 2 weeks after infection. Markers of HIV-1 infection were not detected in any of the gp120-vaccinated animals during 12 months of follow-up. Antisera from the gp120-immunized chimpanzees were unable to neutralize the challenge virus cultured in peripheral blood mononuclear cells (PBMC). These studies demonstrate that immunization with recombinant gp120 derived from a T cell-adapted isolate prevented infection by a heterologous primary isolate of HIV-1. The results suggest that in vitro virus neutralization assays utilizing primary isolates cultured in PBMC may be imperfect indicators of protection in vivo.

AIDS Vaccines↗
PubMed1987

Safety issues related to the use of recombinant DNA-derived cell culture products. I. Cellular components.

Anti-thymocyte serum (ATS) treated newborn rats were used to assess the tumorigenic potential of mammalian cell and mammalian cell culture derived substances. Injection of as much as 100 micrograms of Chinese hamster ovary (CHO) DNA, an amount in excess of 10(8) fold more than might be present in one dose of a typical final product derived from mammalian cell cultures, failed to initiate a tumor in immunosuppressed animals. In addition, injection of 10 micrograms of activated oncogene cloned from a human bladder carcinoma was also insufficient to initiate a tumor in immunosuppressed animals. Injection of some but not all CHO cell lines did result in tumor growth which upon isoenzyme analysis was verified to be of hamster origin. Of importance was the finding that recombinant tissue plasminogen activator (rt-PA) and hepatitis B surface antigen (HBsAg) vaccine failed to induce tumors in either normal or immunosuppressed rats. The results suggest that the presence of minute quantities of CHO derived nucleic acid fragments in these final products have no discernable tumorigenic potential.

Animals↗
PubMed1985

Can variola-like viruses be derived from monkeypox virus? An investigation based on DNA mapping.

The results are presented of a special study to determine whether variola-like "whitepox" viruses could arise as white pock variants of monkeypox virus after one or a few mutations. DNA mapping by cross-hybridization of restriction endonuclease DNA fragments was carried out on 18 orthopoxviruses relevant to this study, including variola and monkeypox viruses and white (non-haemorrhagic) pock producers recovered from chorioallantoic membranes infected with red (haemorrhagic) pock-producing monkeypox viruses. The distinctiveness of the DNA maps of true variola and monkeypox viruses indicated that spontaneous production of "whitepox" from monkeypox virus was genetically impossible. These and other observations led to the conclusion that the "whitepox" viruses recovered from monkeypox virus stocks had an exogenous origin.

Animals↗
PubMed1983

Molecular cloning and sequencing of the La Crosse virus S RNA.

Complete double-stranded DNA copies of the La Crosse virus (LAC) S genome have been synthesized and cloned into plasmid pBR322. The cloned genome was characterized and sequenced. The LAC S genome consisted of 981 nucleotides and contained two overlapping open reading frames. The first reading frame begins at nucleotide 82 and encodes a protein of 235 amino acids. A polypeptide of 92 amino acids can be translated in a +1 reading frame 16 nucleotides downstream from the start of the first reading frame. This second reading frame is initiated with two AUG codons followed by the serine codon UCG, the same serine codon which immediately follows the AUG of the first reading frame.

Amino Acid Sequence↗
PubMed1983

Rabies virus glycoprotein analogs: biosynthesis in Escherichia coli.

The surface of rabies virus is composed of an approximately 60,000 dalton glycoprotein, in which most of the antigenic and immunogenic determinants of the virus reside. We have constructed plasmids for the direct expression in Escherichia coli of the mature full length rabies glycoprotein gene and also for the expression of a glycoprotein gene which has been truncated to exclude the coding region for a hydrophobic, possibly transmembrane, domain of the protein. Escherichia coli harboring the plasmids synthesize analog proteins which conform by several biochemical and antigenic criteria to rabies glycoprotein.

Amino Acid Sequence↗
PubMed1983

Multiple leader RNAs and messenger RNAs are transcribed from the La Crosse virus small genome segment.

Nucleotide sequencing has demonstrated that the Small genome segment of Bunyaviruses contains the genetic information for two viral proteins (N and NSs) in overlapping reading frames (Akashi and Bishop, 1983; Cabradilla et al., in press). Using 3' end-labeled genome probes, La Crosse virus (LAC) infected cells were shown to contain three leader RNAs, which start at position 1 and terminate at approximate positions 74, 95, and 115 from the 3' end of the genome. Primer extension and S1 mapping studies have shown that LAC-infected cells contain seven mRNAs, five of which initiate at positions 1, 74, 101, 117, and 123 and two more which initiate at approximate positions 147 and 159 from the 3' end of the Small genome segment. The existence of multiple leader RNAs and mRNAs from the Small genome segment may allow access to both overlapping reading frames by ribosomes that still initiate only at 5' proximal AUGs, without the need to splice the mRNA.

Bunyaviridae↗
PubMed1983

The changing etiology of epidemic keratoconjunctivitis: antigenic and restriction enzyme analyses of adenovirus types 19 and 37 isolated over a 10-year period.

Strains of adenovirus types 19 (Ad-19) and 37 (Ad-37) isolated from cases of epidemic keratoconjunctivitis (EKC) over a 10-year period were analyzed for differences in antigenic and restriction enzyme patterns. By restriction analysis, 35% of the isolates recovered between 1973 and 1981 and typed by hemagglutination-inhibition tests as Ad-19 were in fact Ad-37. This finding was confirmed by comprehensive serologic tests when Ad-37 reagents became available in 1981. All Ad-19 strains isolated between 1973 and 1980 were identical to the previously described genotype Ad-19A, and these Ad-19A strains exhibited a differential hemagglutination profile distinct from that of Ad-19 and Ad-37 prototypes. The earliest Ad-37 case found in the United States occurred in April 1976; Ad-37 then became the major agent of EKC from 1977 to 1983. Intermediate strains between types 19A and 37 were not detected by either antigenic or restriction fragment analyses. Thus, some genetic event appears to generate new genotypes such as Ad-19A and serotypes such as Ad-37.

Adenoviridae Infections↗
PubMed1983

Oligonucleotide fingerprint analysis of enterovirus 70 isolates from the 1980 to 1981 pandemic of acute hemorrhagic conjunctivitis: evidence for a close genetic relationship among Asian and American strains.

Enterovirus 70 isolates obtained in Asia and the Americas between 1980 and 1981 from cases of acute hemorrhagic conjunctivitis were found to be very closely related by RNase T1 oligonucleotide fingerprinting. Two closely related isolates from the first acute hemorrhagic conjunctivitis epidemic (1969 to 1972) differed by many oligonucleotides from the 1980 to 1981 pandemic strains. The strong similarities of oligonucleotide patterns of isolates from the same epidemic but from distant regions of the world suggest that the genome of enterovirus 70 tends to be conserved during natural infection, a possible consequence of the transient nature of the disease.

Acute Disease↗
PubMed1983

Isolation of the ends of La Crosse virus small RNA as a double-stranded structure.

The genome of La Crosse virus, a member of the Bunyaviridae, is made up of three molecules. Circular nucleocapsid structures, in three size classes, have been isolated from La Crosse virus (Obijeski et al. J. Virol. 20:664-675, 1976). Recently, Obijeski et al. (Nucleic Acids Res. 8:2431-2438) have found that the 5' and 3' ends of each segment are complementary in sequence. We determined that a 5' and 3' end complementary structure, predicted by the rules of Tinoco et al. (Nature [London] 230:362-367), can and will anneal under certain conditions. This structure is resistant to RNase in high-salt medium and can be isolated in a reasonably high yield.

Base Sequence↗
PubMed1981

Multiple genetic changes can occur in the oral poliovaccines upon replication in humans.

Poliovirus isolates of serotypes 2 and 3 from patients whose paralytic poliomyelitis cases were classified as oral vaccine-associated were analysed by oligonucleotide mapping of the virus genomes and by polyacrylamide gel electrophoresis of the virus proteins. Oligonucleotide maps of all isolates were similar to the maps of the corresponding oral vaccine strain. No two isolates gave identical maps. Most maps differed from that of the vaccine strain by at least one oligonucleotide spot. Maps of some isolates revealed numerous differences, indicating that multiple (greater than 100) genetic changes had occurred in the vaccine virus genomes during replication in one or two individuals. In contrast, maps of some neural tissue isolates showed minimal differences from the reference vaccine maps, raising the possibility that neurovirulence may be restored by a small number of genetic changes. For many isolates, changes were also detected in the mobilities of processing rates of the virus proteins.

Adult↗
PubMed1981

Strain characterization studies of poliovirus type I isolates from poliomyelitis cases in the United States in 1979.

In 1979 there was a small outbreak of poliomyelitis among non-immunized Amish individuals in the United States. Epidemiological evidence linked these cases to those in Canada in 1978 which themselves were related to cases in the Netherlands in 1978. Poliovirus type 1 was found to be the cause both in the US and in the other countries. Strain characterization tests were carried out on virus isolates from all three outbreaks. All the type 1 strains were non-vaccine-like both with the absorbed strain specific antisera and with the modified Wecker test. However, the latter as well as the rct test used to characterize these strains are obviously not very discriminating marker tests. The oligonucleotide mapping procedure appears to be a much more definitive approach to recognizing relationships between polioviruses. The various marker tests provided laboratory data in support of the epidemiological evidence that the poliovirus type 1 spread from Holland to Canada in 1978 and from there to the US in 1979.

Disease Outbreaks↗
PubMed1980

Nucleotide sequences at the terminal of La Crosse virus RNAs.

The 5' and 3'-terminal sequences of the three RNA molecules which make up the genomes of La Crosse virus are reported. Eleven nucleotides at both the 5' and 3' termini of all three RNAs are conserved and complementary. In addition more extensive unique sequence complementarity is present in at least two of the three RNAs.

Base Sequence↗
PubMed1980

Studies on the poxvirus Cotia.

The poxvirus Cotia was studied by electron microscopy and by serological and biochemical analyses. Thin-sectioned preparations of infected Vero cells indicated that Cotia virus morphogenesis was similar to other mammalian poxviruses; unique filamentous structures and inclusion matrices were apparent in the cytoplasm. Complement fixation tests that included purified Cotia virions showed a reciprocal cross-reaction with rabbit myxoma virus and no cross-reaction with vaccinia virus. Serological results coupled with gradient polyacrylamide gel electropherograms of the structural proteins of purified Cotia, vaccinia, myxoma and fibroma viruses suggested that Cotia virus was similar to the latter two viruses. Agarose gel electropherograms of cleavage fragments of each of these virus DNAs digested with three separate restriction endonucleases showed that each of these viruses had a unique DNA gel profile.

Animals↗
PubMed1980

The structural proteins of rabies virus and evidence for their synthesis from separate monocistronic RNA species.

Purified preparations of the CVS strain of rabies virus, which were labelled during the infectious growth cycle with different isotopes or labelled in vitro by iodination or acetylation, contained five major proteins, L, G, N, M1, and M2, when examined by polyacrylamide gel electrophoresis (PAGE). The major surface glycoprotein, G, could be separated into two components, G1, G2, in some PAGE systems; they were present in about equimolar amounts and had apparent mol. wt. of 70.5 X 10(3) and 65 X 10(3), respectively. The virus nucleocapsid (p = 1.28 g/ml) could be isolated after detergent treatment of purified virus. It contained the virus RNA, the major nucleocapsid protein, N (mol. wt. 58.5 X 10(3)), and small amounts of a large protein, L (mol. wt. 170 X 10(3)). Two membrane proteins, M1 (mol. wt. 39.5 X 10(3)) and M2 (mol. wt. 25 X 10(3)), were also observed. Chromatography of dissoliated rabies virus in agarose columns with guanidine hydrochloride did not resolve any additional virus structural proteins. Two-dimensional peptide may analysis of iodinated structural proteins indicated that they were unique gene products and not derived from a precursor polypeptide by cleavage. The peptide maps of the two glycoproteins, G1 and G2, appeared identical. The approximate number of proteins molecules per virion has been determined. Rabies virus-directed protein synthesis in BHK21 cultures was detected as early as 6 h p.i. and all the proteins were present 12h p.i. Additional non-structural virus-specific proteins were not observed. The NaCl hypertonic shock procedure, which differentially inhibits polypeptide chain initiation in different classes of mRNAs, was used to ihibit the synthesis of the G and M1 proteins relative to the others selectively. All the rabies virus proteins were synthesized simultaneously following release from hypertonic treatment, suggesting that there are independent polypeptide chain initiation sites for the synthesis of each of the rabies proteins and that each protein is derived via translation of monocistronic mRNA species.

Animals↗