Preparation and use of erythrocyte-globulin conjugates to Lassa virus in reversed passive hemagglutination and inhibition.
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Conditions were defined for functional covalent coupling of anti-Lassa virus globulins to glutaraldehyde-fixed chicken erythrocytes. Tolylene-2,4-diisocyanate in a reaction mixture containing not more than 0.01 M NaCl produced uniformly good conjugates which were used in reversed passive hemagglutination (RPH) and reversed passive hemagglutination inhibition (RPHI) tests to detect Lassa virus antigens in infected cell cultures and specific antigens in Vero cell cultures. Identical results were obtained with this method and with immunofluorescent-antibody (IFA) staining in the detection and identification of Lassa virus isolated from human and rodent specimens from West Africa. The RPHI method was equal to IFA for serological diagnosis of acute human Lassa virus infection and superior to IFA, complement fixation, and a radioimmunoassay procedure for detection of Lassa virus antibodies in a human population where this infection is endemic. (+info)
Preparation of polyvalent viral immunofluorescent intracellular antigens and use in human serosurveys.
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A method is described for preparation of polyvalent antigens for use in rapid screening for immunofluorescent antibodies to Lassa, Marburg, and Ebola viruses. The technique uses mixtures of specifically infected Vero cells placed on Teflon-templated microscopy slides. It was found to be as sensitive as the use of monovalent antigens for detection and quantitation of antibodies to these highly hazardous human pathogens. (+info)
Pathologic and virologic study of fatal Lassa fever in man.
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Postmortem examination of 21 virologically documented cases of Lassa fever, including 6 complete autopsies, was performed as part of a field study of community-acquired Lassa fever in Sierra Leone. The most consistently observed lesions were hepatocellular, adrenal, and splenic necrosis and adrenal cytoplasmic inclusions. Neither these lesions, nor other milder and less constantly observed lesions such as myocarditis, renal tubular injury, and interstitial pneumonia, appeared severe enough to explain the cause of death in Lassa fever. The central nervous system (CNS) contained no specific lesions. Viral titrations demonstrated high viral content in liver, lung, spleen, kidney, heart, placenta, and mammary gland. Clinical laboratory data included elevation of hepatic enzymes, creatine phosphokinase (CPK), and blood urea nitrogen (BUN). Because of the paucity of pathologic lesions in spite of widely disseminated viral infection, further investigation of humoral inflammatory mechanisms is indicated. (+info)
Inactivation of Lassa, Marburg, and Ebola viruses by gamma irradiation.
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Because of the cumbersome conditions experienced in a maximum containment laboratory, methods for inactivating highly pathogenic viruses were investigated. The infectivity of Lassa, Marburg, and Ebola viruses was inactivated without altering the immunological activity after radiation with Co60 gamma rays. At 4 degrees C, Lassa virus was the most difficult to inactivate with a rate of 5.3 X 10(-6) log 50% tissue culture infective dose per rad of CO60 radiation, as compared with 6.8 X 10(-6) log 50% tissue culture infective dose per rad for Ebola virus and 8.4 X 10(-6) log 50% tissue culture infective dose per rad for Marburg virus. Experimental inactivation curves, as well as curves giving the total radiation needed to inactivate a given concentration of any of the three viruses, are presented. We found this method of inactivation to be superior to UV light or beta-propiolactone inactivation and now routinely use it for preparation of material for protein-chemistry studies or for preparation of immunological reagents. (+info)
Pichinde virus L and S RNAs contain unique sequences.
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Using oligodeoxyribonucleotides produced by limited DNase I digestion of calf thymus DNA as a primer, we synthesized complementary DNA (cDNA) from the L and the S RNAs of Pichinde virus. The reaction conditions for in vitro cDNA synthesis were optimized to allow transcription of about 90% of either L or S RNA. No significant hybridization was observed when the L cDNA was hybridized to the S RNA, or when the S cDNA was hybridized to the L RNA. The results indicate that the L and S RNAs of Pichinde virus contain unique nucleotide sequences. (+info)
Polypeptide synthesis catalysed by components of Pichinde virus disrupted by detergent.
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Pichinde virus preparations were investigated for ribosomal components and associated activities. After detergent treatment and fractionation, viral components were assayed for polypeptide synthesis, elongation of nascent polypeptide chains, and mRNA activity. It was demonstrated that these subviral particles could synthesize polypeptides when exogenous mRNA template, aminoacyl--tRNAs, translation factors, GTP and appropriate cations were added. Undisrupted, whole virions could not synthesize polypeptide; disruption and subsequent centrifugation of subviral ribosomes was a prerequisite for the biosynthetic activity described. (+info)
Oligonucleotide fingerprint analysis of Tacaribe virion RNA.
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Polyacrylamide gel electrophoretic analysis of RNA segments of the arenaviruses Pichinde (Pic) and Tacaribe (Tac) showed them to be distinguishable in that Pic S RNA had a slower electrophoretic mobility than Tac S RNA. The L and S RNA segments of Tac virions were found to have distinct RNase T1 oligonucleotide fingerprints, indicating that they are unique RNA species. The oligonucleotide patterns of the Tac L and S RNAs were also distinct from those of the corresponding Pic RNA segments. (+info)
The Tacaribe arenavirus small zinc finger protein is required for both mRNA synthesis and genome replication.
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An antiserum to a peptide of the Tacaribe virus Z protein was used to determine whether this small Zn(2+)-binding protein was required for viral RNA synthesis in infected cell extracts. Specific immunodepletion of the extracts invariably reduced genome synthesis to near background levels, but strong effects on mRNA synthesis occurred only early in the infection or when mRNA synthesis was relatively weak. Our results suggest that the Z protein is required for both mRNA and genome synthesis, but in somewhat different manners. (+info)