Sequence relationships between the genome segments of human and animal rotavirus strains

The sequence relationships of a range of cultivable and noncultivable human and animal rotaviruses were investigated by hybridization of rotavirus cDNA probes to genomic RNAs immobilized on diazobenzyloxymethyl paper. Under conditions of low stringency (34% base mismatch tolerated) most genome segments exhibited partial homology except for genes 4 and 5. In contrast, under more stringent conditions of hybridization in which no more than 8% base mismatch was tolerated, few segments exhibited homology. Generally the human and animal rotaviruses were found to possess distinct nucleic acid sequences that exhibit only a low order of sequence relatedness. These results are consistent with the notion that both cumulative changes in nucleic acid sequences and the interchange of segments may be involved in the evolution of distinct rotavirus strains.

Rotavirus infection in Otago: a serological study

A method for measuring rotavirus antibody in human sera has been established using enzyme-linked immunosorbent assay (ELISA). A Simian strain of rotavirus (SA11) was used as the antigen. Serum eluted from dried blood spots on good quality chromatography paper was found suitable for analysis. Paired serum samples from children with gastroenteritis have shown a brisk antibody response in association with the presence of rotavirus in the faeces. Community studies indicate that although all older children and adults tested have detectable antibodies to rotavirus, there is a significant rise in the number of individuals with high titre antibody in the child bearing age group, after which the levels diminish. This finding suggests that repeated infections occur throughout childhood and early adult life.

Rotavirus infection in New Zealand

Rotavirus infection is commonly found in young infants admitted to hospital with gastroenteritis. An enzyme-linked immunosorbent assay (ELISA) for virus diagnosis is described and the results of testing stool specimens from 497 children with gastroenteritis, 192 neonates and 247 asymptomatic six month old infants are presented. Rotavirus infection was found in 45 percent of all children with gastroenteritis but only in 4.7 percent of neonates and 2 percent of asymptomatic infants. These results do not support the proposal that children in our community have a high incidence of subclinical infections.

Antibodies against double-stranded RNA in patients with rheumatoid arthritis, osteoarthrosis and Paget's disease of bone

Using a liquid phase radioimmunoassay to detect antibodies to 3H-labelled double-stranded RNA the premise that rheumatoid arthritis and Paget's disease of the bone may be associated with a chronic virus disease was examined. About 33% of patients with rheumatoid arthritis had antibody levels above the normal range and 11% had antibody levels below the normal range of controls (blood bank donors). The low binding activities were attributed to the action of a nuclease that degraded the dsRNA. Some patients with Paget's disease of bone had higher binding activities than the normal range and similar binding activity was also found in patients with osteoarthrosis. The increase in antibodies to double-stranded RNA did not correlate with increasing age.

Parainfluenzavirus upper respiratory tract illnesses in partially immune adult human subjects: a study at an Antarctic station

Outbreaks of respiratory tract illnesses (RTI) in adult humans during October and November 1975 at McMurdo Station, Antarctica, were investigated by viral isolation and serologic procedures. The recovery of viral agents was enhanced by use of cell cultures in the field. Recoveries of parainfluenzaviruses types 1 and 3 and rhinoviruses were made from 10 of 39 nasal washings. Parainfluenzaviruses types 1 and 3 accounted for 50 and 30 per cent, respectively, of the total viruses recovered during October and November 1975. Acute and convalescent sera collected from 32 adult humans were examined for antiviral antibody by hemagglutination inhibition (HI) and radioimmunoassay (RIA) techniques. Serologic responses (HI and RIA) confirmed that parainfluenzaviruses were the predominent cause of RTI at McMurdo Station during that time. The temporal relationship between parainfluenzaviral diseases occurring in US communities and at McMurdo suggests that these viruses are transported to the Antarctic by personnel originating within the US. Standardization of the RIA allowed sequential assay of large numbers of sera using multiple preparations of radiolabeled indicator antibody, while ensuring the reproducibility of antiviral antibody titers to within one twofold dilution between subsequent labeled antibody preparations. The RIA detected both lower levels of virus specific antibody and more serologic responses than could be detected by HI.

Comparison of Solid-Phase Radioimmunoassays for Baculoviruses

The sensitivity and cross-reaction of four solid-phase radioimmunoassays (RIA) for Trichoplusia ni nuclear polyhedrosis virus containing singly enveloped virions were investigated. The detection limits of each assay were as follows: Indirect RIA, 5 ng of dissolved polyhedron antigen; direct RIA, 50 ng; indirect sandwich RIA, 200 ng; and direct sandwich RIA, 300 ng. The indirect and indirect sandwich RIAs showed considerable cross-reaction with other baculovirus antigens, but the direct and direct sandwich RIAs showed cross-reaction with only one closely related baculovirus. When microtiter plates used for the solid phase were pretreated with bovine serum albumin, nonspecific binding of labeled antibodies was reduced to a minimum. Antibodies prepared by an immunoadsorption procedure showed greater specific binding than antibodies prepared by ammonium sulfate precipitation of the immunoglobulin fraction. Highly contaminated antigen could not be detected by the indirect RIA, but the direct sandwich RIA was unaffected by antigen contamination. Antigen making up 0.0025% (wt/wt) of a sample of bird droppings could be detected by the direct sandwich RIA.

Alkaline Protease Associated with Virus Particles of a Nuclear Polyhedrosis Virus: Assay, Purification, and Properties

Proteolytic activity was detected within polyhedra of the nuclear polyhedrosis virus of Spodoptera littoralis . The enzyme activity was detected by its ability to degrade the major structural polypeptide of polyhedra (polyhedrin). A quantitative assessment of activity was made by a radioassay technique using 3 H-labeled polyhedrin as the substrate. Of the structural components of polyhedra, virus particles showed the greatest specific proteolytic activity. Preparations of purified nucleocapsids were inactive. The virus particle enzyme displayed a temperature optimum for proteolysis of 30 to 40°C and a pH optimum of 9.6. Its activity was inhibited by H 2+ and Cu 2+ , but not by 2-mercaptoethanol. The enzyme was purified from detergent-treated virus particles by affinity column chromatography, using polyhedrin linked to cyanogen bromide-activated Sepharose. Three major envelope polypeptides (L107, L85, and L71) bound to the column at 4°C, but after incubation at 31°C, polypeptide L71 alone was eluted. The fractions containing this protein exhibited a specific enzyme activity more than 80-fold greater than that present in polyhedra. The possible significance of the alkaline protease, and other proteins with affinity for polyhedrin, is discussed.

Effect of Alkaline Protease on the Antigenic Nature of Wiseana Nuclear Polyhedrosis Virus Polyhedron Protein

Polyhedron protein from Wiseana spp. nuclear polyhedrosis virus was found to be degraded by an alkali protease when polyhedra are dissolved in alkali. The protease activity did not occur at high pH (0.1 M NaOH) and was inactivated by heating polyhedra to 70°C for 3 h. The products from the protease degradation of Wiseana spp. nuclear polyhedrosis virus polyhedron protein retain the antigenicity of undegraded polyhedron protein as measured by the direct solid-phase radioimmunoassay and immunoadsorption. Degradation products below 27,000 daltons could not be detected by the sandwich radioimmunoassay, indicating that they are probably monovalent.

Solid phase radioimmunoassay using labelled antibodies: a conceptual framework for designing assays

A simple theoretical model for the antigen-antibody reaction is presented ans used to evaluate the optimum conditions for designing solid phase radioimmunoassay (RIA) using labelled antibodies. Both theoretical and experimental data are presented, using a wide variety of antigens and their corresponding antibodies. The types of RIA is described include the direct, the indirect, sandwich assays for detecting either antigen or antibody. The experimental results confirm in a semiquantitative manner that the greatest sensitivity of the RIA is achieved when the smallest amount of labelled antibody is used, that whenever possible the antigen/antibody ratio should be greater than unity (greater than 1), and that the formation of the antigen-antibody comples is dependent on the mass action effect.

A solid-phase radioimmunoassay for polyhedron protein from baculoviruses

A solid-phase radioimmunoassay has been developed for detecting polyhedron protein of Wiseana spp. nuclear polyhedrosis virus (W.NPV) using antigen fixed to plastic microtiter wells. The direct assay using 125I-labeled rabbit immunoglobulins could detect 0.2 microng of polyhedron protein, and the indirect method using 125I-labeled sheep antirabbit immunoglobulins could detect 0.05 microng of polyhedron protein. Antibodies against W.NPV polyhedron protein could be detected using a competition assay with labeled and unlabeled antibodies, providing a method suitable for rapid and quantitative screening of sera.

Detection of double-stranded RNA in Semliki Forest virus-infected cells by an indirect solid phase radioimmunoassay: an assay for interferon

An indirect solid phase radioimmunoassay using rabbit antibodies to the synthetic double-stranded RNA poly rI-rC and 125I-labelled sheep anti-rabbit IgG could detect 1 ng of poly rI-rC. This assay could also detect the presence of double-stranded RNA in Semliki Forest virus-infected chick fibroblasts and can be used as an assay for interferon activity.

Detection of virus-specific immunoglobulins using a doubly labeled fluorescein-125I antibody

Commercially prepared fluorescein-labeled antihuman antibodies were labed with 125I and used to compre specific herpes simplex virus antibody titers as determined by indirect fluorescent antibody and radioimmunoassay techniques. Total virus-specific immunoglobulin and virus-specific immunoglobulin G titers did not vary by more than one twofold dilution when compared by the two methods.

Antibodies ot double-stranded RNA: specificity and serum nucleases

An antiserum was prepared in rabbits to the synthetic double-stranded ribonucleic acid (ds RNA) poly rI:rC. Using a liquid-phase radioimmunoassay, the antiserum cross-reacted with a natural ds RNA isolated from the cytoplasmic polyhedrosis virus of the silkworm, binding 95% of the RNA at a 1 : 20 serum dilution. Preliminary tests of the specificity of the antiserum showed that it did not bind single-stranded RNA (ss RNA) or deoxyribonucleic acid (DNA), but also revealed that the serum contained an enzyme activity which degraded ss RNA into acid-insoluble fragments. It was therefore possible that the failure to bind ss RNA resulted from the degradation of the antigen rather than from an absence of cross-reacting antibodies. However, when the serum ribonuclease activity was inhibited by macaloid, the antiserum still did not bind the ss RNA antigen. This demonstrated that the antibodies to ds RNA did not cross-react with ss RNA. The existence of serum enzymes capable of degrading nucleic acid antigens emphasizes the need for caution in assessing the specificity of such antisera.

Localisation and pathology of Mortierella wolfii toxin in mice

Using 125I labelled M. wolfii toxin the site of action in mice was shown to be the kidney. Autoradiographic studies revealed the label to be localised in the proximal convoluted tubules of the kidney, where there was a marked necrosis and degeneration of the epithelium causing the tubules to become considerably distended. Although the distal and collecting tubules maintained their integrity, many contained amorphous casts. An injected dose of 1 toxic unit (10 mug protein) was sufficient to produce damage to the kidney with subsequent anaemia, azotemia and albuminuria. Other organs appeared to be essentially normal and renal failure was the probable cause of death of mice.