ABSTRACT
The dot ELISA technique was applied for direct detection of BK virus in clinical urine samples. The assay was performed on nitrocellulose paper dotted with the polyethylene glycol precipitated urine samples free of cellular debris. BK virus was detected with an anti-BK virus monoclonal antibody, and the complex was visualized by immunoperoxidase staining. Positive reaction appeared as well-defined dark blue spots. Of the 110 urine samples examined, 31 were positive in the dot ELISA and 79 proved negative. Comparing with the IIF results, the dot ELISA had a 88.46% of sensibility and 90.4% of specificity, and the results agreed completely in 99 samples. The simple dot ELISA technique can be recommended for detection of BK virus excretion in routinary diagnostic.
Subject(s)
Antigens, Viral/urine , BK Virus/immunology , Tumor Virus Infections/diagnosis , Animals , Antibodies, Monoclonal/immunology , Chemical Precipitation , Enzyme-Linked Immunosorbent Assay , Humans , Immunoblotting , Immunoglobulin G/immunology , Peroxidase , Vero CellsABSTRACT
Three methods used for the detection of BK virus in urine specimens, the indirect immunofluorescence test, the dot enzyme immunoassay and the DNA-DNA hybridization assay, were compared by testing specimens from 49 immunocompromised patients. All three assays were effective in detecting BK virus. The technical advantage of each of them was discussed. The immunofluorescence test was found to be the simplest one to perform; the DNA-DNA hybridization assay displayed exquisite sensitivity; and the easy reading of the dot enzyme immunoassay did not require the specialized training inherent to immunofluorescence assays. The dot enzyme immunoassay might therefore be the most practical method for screening urine specimens of immunocompromised patients, especially when the sediment is poor in cells. Conversely, the indirect immunofluorescence test might be the method of choice for checking patients with haemorragic cystitis whose urine samples usually contain large amounts of cells.
Subject(s)
BK Virus/isolation & purification , DNA, Viral/analysis , Nucleic Acid Hybridization , Polyomavirus/isolation & purification , Urine/microbiology , BK Virus/genetics , BK Virus/immunology , Fluorescent Antibody Technique , Humans , Immune Tolerance , Immunoenzyme TechniquesABSTRACT
The study with an Enzyme Linked Immunosorbent Assay of the sera of 57 infants aged less than 9 weeks and developing a bronchiolitis, argues for the absence of a protective role for the maternally transmitted anti-respiratory syncytial virus (RSV) IgG and for the existence of a positive relationship between these antibodies levels - which are not neutralizing - and the severity of RSV bronchiolitis.
Subject(s)
Bronchiolitis, Viral/immunology , Immunity, Maternally-Acquired , Respirovirus Infections/immunology , Antibodies, Viral/immunology , Fluorescent Antibody Technique , Humans , Immunoglobulin G/analysis , Infant , Infant, Newborn , Respiratory Syncytial VirusesABSTRACT
A simplified and reliable enzyme-linked immunosorbent assay (ELISA) was applied to the detection of serum antibodies against respiratory syncytial virus (RSV). RSV-infected cells were fixed and dried on 96-well microtiter plates and kept at 4 degrees C. The titers of reference sera were determined by endpoint dilution. A linear relation was found between the titers and the logarithm of absorbance values of sera diluted to 1:1,000 (r = 0.93, P less than 0.001). Measurement of RSV antibodies was done by using a single serum dilution (1:1,000) in conjunction with a standard curve. A strong correlation was found between complement fixation and ELISA results (r = 0.89, P less than 0.001). In addition, the ELISA method exhibited higher titers and a greater sensitivity than did complement fixation, although the applicability of the assay is limited with positive serum samples of low titer.
Subject(s)
Antibodies, Viral/analysis , Respiratory Syncytial Viruses/immunology , Animals , Antibody Specificity , Child, Preschool , Complement Fixation Tests , Enzyme-Linked Immunosorbent Assay , Humans , Infant , Vero CellsABSTRACT
Two monoclonal antibodies against influenza A virus were assessed for use as diagnostic reagents in an indirect immunofluorescence assay (IFA) of nasopharyngeal secretions. Monoclonal antibody IA-52, directed at an internal antigen, reacted with all influenza A tested. The high stability of this epitope permitted its use in a rapid IFA test, which gave results comparable to those obtained with polyclonal antibodies and viral isolation. The second monoclonal antibody, IA-279 was directed at a surface epitope (hemagglutinin); it reacted with almost all H3 subtype strains. Positive IFA using these monoclonal antibodies permitted rapid preliminary differentiation between the current two major subtypes of influenza A virus (H1N1, H3N2).
Subject(s)
Antibodies, Monoclonal , Antigens, Viral/analysis , Influenza A virus/isolation & purification , Influenza, Human/diagnosis , Nasopharynx/microbiology , Antibodies, Viral , Fluorescent Antibody Technique , Hemagglutinins, Viral/analysis , Humans , Influenza A virus/immunology , Nasopharynx/metabolismABSTRACT
We developed five monoclonal antibodies against respiratory syncytial virus. Three of these (23A3, 12A4, and 18B2) were used in an indirect fluorescent antibody test, and the results were compared with those of a similar indirect fluorescent test with commercial anti-respiratory syncytial virus serum. The results obtained with antibody 18B2 and commercial anti-respiratory syncytial virus serum were identical, whereas with antibodies 23A3 and 12A4 the incidence of positive identifications was around 50%.
