Peroxidase-labeled primary antibody method for detection of pestivirus contamination in cell cultures.

Contaminating bovine viral diarrhea (BVD) virus in cell cultures and in fetal bovine serum (FBS) is a well recognized problem. This study describes a direct peroxidase (DP) labeled primary antibody method for detection of pestivirus antigens in cell culture that is simple and reliable. Using this method, most bovine and porcine cell cultures, a cat lung, four mosquito and two monkey cell cultures were found contaminated with BVD virus. The rodent and human cell cultures tested were negative by this method for BVD virus.

Avidin-biotin latex agglutination assay for detection of antibodies to viral antigens.

A new method for attaching antigens to latex by an avidin-biotin technique is described. The procedure permits control of the amount of antigen attached to the latex and eliminates the need for highly purified antigens and destructive bridging chemicals. The avidin-biotin latex agglutination assay is a simple, rapid test well suited to detection of viral antibody. The sensitivity and specificity, respectively, of the avidin-biotin latex agglutination assay compared with other assay results for antibody to viruses were as follows: cytomegalovirus, 98 and 100% (indirect hemagglutination assay); measles virus, 96 and 100% (enzyme-linked immunosorbent assay); and herpes simplex virus, 78 and 100% (indirect hemagglutination assay).

Capillary enzyme immunoassay for rapid detection of herpes simplex virus in clinical specimens.

Capillary enzyme immunosorbent assay (CapELISA) is a modification of the standard enzyme immunosorbent assay which permits rapid detection of viral antigens in clinical specimens. The capillary tube format provides a very large reactive surface relative to the sample size. The close proximity of antigen to antibody in the tube optimizes the reaction, resulting in increased sensitivity and shorter incubation requirements. Sensitivity is further enhanced by use of a biotin-avidin enzyme detector system and a fluorogenic rather than a colorigenic substrate. The assay is performed at ambient temperature and requires less than 2 h. It is read with an inexpensive hand-held black light. Data for the use of CapELISA for the detection of herpes simplex virus in clinical specimens are presented. The results show greater than or equal to 85% sensitivity and 100% specificity when compared with tissue culture tests on the same samples. This new system should be advantageous for the diagnosis, treatment, and management of patients with herpesvirus infections and for the prevention of neonatal herpes acquired by passage of the fetus through an infected birth canal.

Comparison of enzyme-linked immunosorbent assay with enzyme-linked fluorescence assay with automated readers for detection of rubella virus antibody and herpes simplex virus.

The enzyme-linked immunosorbent assay (ELISA) was compared with the enzyme-linked fluorescence assay (ELFA) for the detection of rubella antibody and herpes simplex virus antigen. Test parameters, specimens, antigen or antibody, and conjugates for the two types of assays were identical except that p-nitrophenyl phosphate was used as the substrate for the ELISA and 4-methylumbelliferyl phosphate was used as the substrate for ELFA. Automated readers were used for both assays. Antibody titers and sensitivity of antigen detection were quite similar for ELISA and ELFA. ELFA for rubella antibody, however, could be conducted with less antigen or shorter substrate incubation time (5 min for ELFA versus 30 min for ELISA). For herpes simplex virus antigen detection, ELFA could also be read after a shorter substrate incubation time (15 min for ELFA versus 30 min for ELISA). Clear polystyrene microtiter plates routinely used for ELISA could be used for ELFA, but clear polyvinyl chloride plates had high background fluorescence. Black polystyrene and polyvinyl chloride plates gave lower background fluorescence than did clear plates. ELFA is of particular value as a substitute for ELISAs in which long substrate incubations are required or antigens of only low titer are available.

Polycarbonate-coated microsticks as solid-phase carriers in an enzyme-linked immunosorbent assay for rubella antibody.

We evaluated the use of microsticks as solid-phase carriers in an enzyme-linked immunosorbent assay for rubella antibody. The microstick enzyme-linked immunosorbent assay was found to be equal in sensitivity to plate and disk enzyme-linked immunosorbent assays and presumably more sensitive than hemagglutination and immunofluorescence assays. The microstick as a solid-phase carrier offers advantages over both plate and bead carriers.

Late postpoliomyelitis muscular atrophy: clinical, virologic, and immunologic studies.

Seventeen relatively young patients, ages 31-65 years (average, 45) with prior poliomyelitis, who after a number of years of stability had experienced new neuromuscular symptoms, were studied. Seven patients had deterioration of functional capacity and then stabilization without new muscular weakness. The other 10 had late postpoliomyelitis muscular atrophy (late PPMA ) characterized by focal progressive muscle weakness, wasting, fasciculations, and muscle pains affecting previously spared muscles or muscles previously affected but recovered. Four patients with late PPMA had lymphorrhages or lymphocytic infiltrates in their biopsied muscle; three of three patients had oligoclonal IgG bands in their spinal fluid, and five had variable peripheral T lymphocyte-subset ratios. In one patient with late PPMA , antibodies to poliovirus were specifically elevated in the cerebrospinal fluid. Our findings indicate that new motor-neuron disease can occur in patients with prior poliomyelitis and that immunopathologic mechanisms may play a role.

Evaluation of various plastic microtiter plates with measles, toxoplasma, and gamma globulin antigens in enzyme-linked immunosorbent assays.

Seventeen lots of microtiter plates which differed in lot, batch, plastic type, or manufacturer were evaluated as solid-phase carriers in enzyme-linked immunosorbent assays for antibodies to measles, toxoplasma, and human gamma globulin. Most plates of polystyrene or polyvinyl chloride were found to give acceptable binding. The final choice depended on the antigen to be attached. Variations in binding between lots, batches, and types of plastic were found. Well-to-well variation was found to be of greater statistical significance than edge effect and should be a consideration in selection of a plate lot for enzyme-linked immunosorbent assays. Lots of plates should be pretested by the investigator to determine whether there is good binding of the antigen to be used and whether there is low plate-to-plate and well-to-well variation.

Acute and subacute demyelination induced by mouse hepatitis virus strain A59 in C3H mice.

Mouse hepatitis virus (MHV, strain A-59), a coronavirus, induced acute and subacute demyelinating disease in the central nervous system of weanling C3H mice that were reported to be genetically resistant to MHV. Subtle clinical signs developed in greater than 90% of animals 5-7 days after intracerebral inoculation of 25 PFU, and foci of demyelination were detected from 1 to 4 weeks postinoculation (p.i.) by histopathology and immunolabeling with antibody directed against myelin basic protein. Infectious virus could be isolated only during the first 10 days p.i., but viral antigens persisted in the cytoplasm of oligodendrocytes in the demyelinating lesions for up to 4 weeks p.i. Serum antibody titers against MHV-A59 rose by 2 weeks p.i. and persisted at high levels for months. This infection of genetically "resistant" animals by a normally hepatotropic strain of MHV can serve as a highly reproducible model for the study of acute and subacute demyelination by a coronavirus.

Rapid latex agglutination test for rubella antibody.

The latex agglutination card test (Rubascan) for the detection of rubella antibody was compared with the standard hemagglutination inhibition and enzyme-linked immunosorbent assay tests. There was complete agreement with sera which had hemagglutination inhibition titers of >/=16. Sera with low levels of antibody which were positive in the enzyme-linked immunosorbent assay, however, gave negative latex agglutination results approximately 25% of the time (false negatives), whereas sera which were negative in the enzyme-linked immunosorbent assay gave false-positive results in about 3% of the cases. The use of capillary "finger stick" plasma instead of venous sera resulted in additional false-negative latex agglutination tests among patients with very low antibody titers. Because of the simplicity of the method, it should be possible to use this test in physicians' offices and in large immunization campaigns. Care should be taken to become completely familiar with the procedures and reading of the agglutination patterns. Control sera should always be used. Interpretation of results should take into consideration the rates of false-negative and false-positive results noted above. These rates apply to sera with little or no antibody. In particular, negative tests should be confirmed with more specific methods in critical cases, such as pregnant women exposed to rubella or women of childbearing age who are being considered for immunization. There was no problem with the latex agglutination findings for sera with higher titers. Since results are available in 8 min, physicians should be able to counsel their patients rapidly and immunize, if necessary, while the patient is still present.

Microsticks as solid-phase carriers for enzyme-linked immunosorbent assays.

Microsticks are machine-tooled or molded pegs of plastic or stainless steel which were developed as solid-phase carriers for the enzyme-linked immunosorbent assay (ELISA). They consist of a stem, which can be coated with plastic to be used as the reactive surface, and a shaft designed for easy handling and labeling and for positioning the sticks in microtiter wells and transfer plates. Microsticks permit a wide selection of coating materials and afford the user greater control over quality and standardization of the solid-phase surface. Polycarbonate and nitrocellulose coatings were tested in ELISAs for antibodies to measles virus, toxoplasma, and human gamma globulin. The Microsticks were found to give reproducible, sensitive, and specific ELISA results and minimized problems due to lot-to-lot and batch-to-batch variations found with other plastic carriers.

Comparison of hemagglutination inhibition test and enzyme-linked immunosorbent assay for determining antibody to rubella virus.

The hemagglutination inhibition test (HAI) and the enzyme-linked immunosorbent assay (ELISA) for detecting antibody to rubella virus were compared by testing 25 sets of paired sera taken before and after infection and 10 sets of sera taken during acute and convalescent stages of the disease and by screening 700 serum samples from the Collaborative Perinatal Project, NIH/NINCDS. The tests were found to be comparable in their ability to detect positive and negative sera, rises in titers, and seroconversions. When a purified antigen and carefully prepared reagents were used, ELISA was found to be as accurate and reliable as HAI. ELISA required no pretreatment of serum, could easily be automated, and was less time-consuming than HAI.

CSF oligoclonal bands, immunoglobulins, and viral antibodies in progressive myoclonus epilepsy.

We studied CSF and serum samples from 16 patients with progressive myoclonus epilepsy (PME). These patients had juvenile-onset PME with evidence of autosomal recessive inheritance and no Lafora bodies. Twelve of the 16 patients with PME had immunologic abnormalities. Oligoclonal gamma bands were seen in six of the eight patients from whom sufficient CSF was available. The CSF albumin and serum/CSF albumin ratios were normal in all 16 patients, indicating the presence of intact blood-brain barriers. Six of the 16 patients showed increased CSF IgG levels and five had an increased CNS IgG synthesis. All patients had normal serum and CSF IgM and IgA levels. Three patients, all with bands, had reduced measles and/or vaccinia serum/CSF antibody ratios. The findings suggest altered immune response of the CNS of some patients with PME apparently caused by nonspecific immunostimulation.

Coronavirus antibodies in sera from patients with multiple sclerosis and matched controls.

Sera from patients with multiple sclerosis and carefully matched controls were tested for antibodies to three strains of coronavirus. There was no significant difference in the levels of antibody in the patients vs the controls. We conclude that unless the strains of coronaviruses recently reported to have been isolated from patients with multiple sclerosis express important serological differences from those used in these studies, coronaviruses are not associated with the cause of multiple sclerosis.

Measles and canine distemper antibody. Presence in sera from patients with multiple sclerosis and matched control subjects.

Antibody to measles virus and canine distemper virus (CDV) was demonstrated in sera from patients with multiple sclerosis (MS) and from carefully matched control subjects. Elevated measles and CDV antibody titers were found in patients with MS when compared with the matched control subjects. The correlation between the measles and CDV antibody titers was quite high, suggesting that the antibody levels between the two viruses are very closely related. Based on the results of our study and a review of the literature, our conclusion is that the CDV antibody levels in patients with MS and matched control subjects are associated with occurrence of measles virus antibodies.