Publications (23)132.6 Total impact
- [Show abstract] [Hide abstract] ABSTRACT: The significance of detecting specific antibody of the IgM class for the diagnosis of parainfluenza infections was examined. Paired sera from 763 children and adults admitted to the hospital for acute respiratory disease were tested for significant antibody titer rises in the hemagglutination inhibition (HI) test and for specific IgM antibody with the hemadsorption immunosorbent techniques (HIT). Sera were collected during two 6-month periods, January through June, 1982 and 1983. Evidence of parainfluenza infections was found in 122 patients (16%): 83 (25%) in 1982 and 39 (9.1%) in 1983. The HIT was superior to the HI test for detection of parainfluenza infection, in particular in infants and aged patients, 94 patients were positive only in the HIT test, 12 in the HI test, and 16 in both tests. In a control group of 120 persons (time-and age-matched to the patients of 1982) admitted for nonrespiratory illness, six (5%) showed parainfluenza IgM in their serum. Blocking experiments and retrospective clinical information indicated that the IgM antibody detected in these individuals is specific IgM acquired after a mild parainfluenza infection. Most (66%) patients showed IgM antibody titer rises or high titers (> 1,280) in both sera, and in 23%, a fall in IgM antibody titer was found. Detection of specific IgM antibody by HIT permitted early presumptive diagnosis in 71% of the patients with parainfluenza infection. IgM antibody persisted for 2–11 weeks. The HIT appears to be an important supplement for the diagnosis of parainfluenza infections.
- [Show abstract] [Hide abstract] ABSTRACT: An antibody capture enzyme-linked immunosorbent assay was developed for detection of immunoglobulin E antibody to cytomegalovirus (CMV-IgE). Affinity-purified anti-human IgE-coated microtiter plates were used to separate IgE from other classes of antibody in serum. Virus-specific IgE was detected by subsequent incubation with horseradish peroxidase-labeled CMV antigen and substrate. The assay was shown to be very sensitive, since in most positive sera CMV-IgE was still detected at a dilution of 1:5,000. Of 45 patients with primary CMV infection, 43 (96%) were found to produce CMV-IgE. In contrast, CMV-IgE was detected in only 4 (9%) of 44 patients with recurrent CMV infection and in 1 of 144 healthy controls. Furthermore, the level of CMV-IgE in patients with recurrent CMV infection appeared to be lower than that in patients with primary infection. Preliminary examination of successive sera suggested that CMV-IgE is produced somewhat slower than CMV-IgM and -IgA but persists for a shorter period. These results suggest that CMV-IgE may be used as an indicator of primary CMV infection.
- [Show abstract] [Hide abstract] ABSTRACT: A direct enzyme-linked immunosorbent assay (ELISA that used peroxidase-labeled antigen) was developed for detection of IgM and IgA antibody to herpes simplex virus (HSV). The assay uses immuno-affinity-purified antihuman IgM or IgA antibody-coated wells of microtiter plates to separate IgM or IgA from other classes of antibody in serum or cerebrospinal fluid (CSF). The presence of specific IgM or IgA is detected by subsequent, consecutive incubation with peroxidase-labeled antigen and substrate. HSV antigen was purified by sucrose gradient centrifugation and coupled with peroxidase by the periodate method. By examining sucrose-gradient-fractionated sera the assays were shown to be specific for IgM and IgA classes of antibody. None of the sera from patients with Epstein-Barr virus (n = 20), cytomegalovirus (n = 20), or varicella-zoster virus (n = 8) infection or with both rheumatoid factor and IgG antibody to HSV (n = 13) reacted positively. Only one out of 78 sera from healthy persons was positive for IgA antibody to HSV, and none for IgM antibody. All 33 patients with HSV infection developed HSV-IgA, 22 developed HSV-IgM. Of the 11 patients with primary infection, all had IgM antibody in their first sera and six had IgA antibody. The corresponding figures for the 22 patients with recurrent infection were five and nine. Furthermore, HSV-IgA antibody was found in serum and CSF of all five patients with HSV encephalitis in the second week after onset of symptoms, indicating the usefulness of the assay as a nonin-vasive technique for diagnosing HSV encephalitis.
- [Show abstract] [Hide abstract] ABSTRACT: A direct enzyme-linked immunosorbent assay (ELISA) is described that uses horseradish peroxidase-labeled antigen for detection of immunoglobulin M (IgM) and IgA antibodies to toxoplasma. In this assay, polystyrene microtiter plates were sensitized with anti-human IgM or IgA antibody to separate IgM or IgA from other classes of antibody. The presence of IgM or IgA antibodies to toxoplasma (Tox-IgM, Tox-IgA) was then detected by sequential addition of soluble horseradish peroxidase-labeled toxoplasma antigen and substrate. As judged by examining sucrose gradient-fractionated sera, the assay was specific for IgM or IgA classes of antibody. In contrast to the indirect immunofluorescence for IgM antibodies to toxoplasma, no inhibition of IgM reactivity by specific IgG antibodies could be detected. Furthermore, rheumatoid factor did not cause false-positive results. Of 80 single sera with high antibody titer to toxoplasma in indirect immunofluorescence and complement fixation, 40 were positive in the direct ELISA for Tox-IgM, 36 were positive in the double-sandwich ELISA, and only 21 were positive in the indirect immunofluorescence for Tox-IgM when whole serum was used. In the indirect immunofluorescence, another 13 sera became positive after sucrose gradient fractionation. The direct ELISA for IgA antibodies to toxoplasma was positive in 43 sera, of which 39 were positive in the direct ELISA for Tox-IgM. High levels of IgM antibodies were found within 3 months after the onset of symptoms, slowly decreasing thereafter. Tox-IgM may persist for more than 1 year after infection.
- [Show abstract] [Hide abstract] ABSTRACT: We used hemadsorption immunosorbent technique (HIT) to detect mumps immunoglobulin M (IgM) antibody. IgM from human sera was adsorbed into anti-human IgM-coated wells in plates, and mumps-specific IgM was detected by adding mumps virus hemagglutinin and guinea pig erythrocytes consecutively. Specific IgM-positive sera showed hemadsorption, whereas negative sera showed hemagglutination. All 81 patients with current mumps infections tested showed mumps-specific IgM antibody, with titers ranging from 160 to 327,680. In most cases IgM antibody was already present on day 1 or 2 after the onset of illness. IgM antibody persisted for 6 to 10 weeks. Of 57 patients with acute respiratory illnesses caused by parainfluenza virus, 5 showed cross-reactions in the hemadsorption immunosorbent technique assay for mumps IgM. The hemadsorption immunosorbent technique assay is specific for the IgM class of antibody and avoids false-positive results due to rheumatoid factor. This test is an efficient and sensitive method for rapid and early diagnosis of mumps infections.
- [Show abstract] [Hide abstract] ABSTRACT: A hemadsorption immunosorbent technique (HIT) was developed for the detection of immunoglobulin M (IgM) to parainfluenza virus types 1, 2, and 3. Twenty-six (90%) of twenty-nine patients under 6 yr of age from whom parainfluenza virus was isolated showed parainfluenza IgM antibody in one or both of their paired sera, with titres ranging from 320 to 81,920. In about one third of the cases IgM antibody was demonstrated in the initial sera taken 1 to 3 days after the onset of illness. Heterotypic IgM antibody responses were observed in about 20% of the patients. The HIT test was more sensitive than the hemagglutination inhibition (HI) and complement fixation tests in detecting a seroresponse in the 29 virus-positive children. The results of studies in older patients with HI titre rises to parainfluenza virus suggested that reinfection probably induced IgM antibody in a proportion of cases. The HIT test proved to be specific for the IgM class of antibody and avoided false-positive results due to rheumatoid factor. It permits an early presumptive diagnosis in a proportion of patients with parainfluenza infection.
- [Show abstract] [Hide abstract] ABSTRACT: Enzyme-linked immunosorbent assays (ELISA) were developed for quantifying cytomegalovirus (CMV) and rubella antibodies using a single serum dilution (1/800) in conjunction with a standard curve. A near linear relation was found between the logarithms of absorbance values of sera at a dilution of 1/800 and the titres as determined by an end point dilution ELISA. The reproducibility of the single dilution ELISA was good; the within-test coefficients of variation averaged 7.5% for CMV antibody and 12.4% for rubella antibody. A close correlation was found between ELISA and complement-fixing (CF) antibody titres to CMV and between ELISA and haemagglutination-inhibition (HI) antibody titres to rubella virus. The titres in ELISA were 200 to 1000 times higher than in CF for CMV and 50 to 100 times higher than in HI for rubella virus.
- [Show abstract] [Hide abstract] ABSTRACT: A direct enzyme-linked immunosorbent assay was developed for the measurement of immunoglobulin M (IgM) antibody to cytomegalovirus (CMV). Wells of microtiter plates were coated with anti-human IgM. Each patient's serum was added at a dilution of 1:100, and IgM from the serum was allowed to react with anti-human IgM. The amount of CMV-specific IgM antibody bound was determined by measuring the intensity of color change after the addition of peroxidase-labeled CMV antigen and substrate. Nuclei of infected cells served as an antigen source. CMV IgM could be detected only in IgM fractions of sera from patients with a recent CMV infection. Rheumatoid factor did not cause false-positive results. No cross-reactions were observed when paired sera from 22 patients with herpes simplex or varicella and single sera from 12 patients with suspected infectious mononucleosis were tested by the direct enzyme-linked immunosorbent assay. Each of 17 patients with a seroconversion for CMV antibody showed CMV-specific IgM antibody. In six of these patients the antibody was detected in the initial serum. The direct enzyme-linked immunosorbent assay for CMV IgM is a specific and sensitive test for the diagnosis of recent CMV infections and possesses distinct advantages over indirect tests.
- [Show abstract] [Hide abstract] ABSTRACT: A highly specific and sensitive hemadsorption immunosorbent technique for measuring rubella immunoglobulin M (IgM) antibody is described. IgM from human sera was absorbed into anti-human IgM-coated wells in plates and rubella-specific IgM was detected by adding rubella virus hemagglutinin and a small quantity of sheep erythrocytes. Centrifugation of the plates facilitated reading of the test. Specific IgM-positive sera showed hemadsorption, whereas negative sera showed hemagglutination. Rheumatoid factor and rubella-specific IgG antibody did not interfere with the results. The test was clearly more sensitive than the solid-phase immunosorbent technique for detection of rubella IgM antibody by hemagglutination inhibition and at least as sensitive as the hemagglutination inhibition test on IgM fractions from a sucrose density gradient and the indirect immunofluorescence test for IgM antibody with absorbed serum. All of 40 sera from 17 rubella patients taken 4 to 49 days after the onset of rash were positive in the new test, with antibody titers ranging from 2,560 to 81,920 between 4 and 28 days. The test is reliable, practical, and suitable for general diagnostic use.
- [Show abstract] [Hide abstract] ABSTRACT: Sera from 1661 persons in 12 age groups from 0 to 79 years were titrated for toxoplasma antibodies in the indirect immunofluorescence test. The sera were collected from patients with symptoms suggestive of acute, mainly respiratory, viral infections. After the first year of life, the prevalence of antibodies started to rise, reaching 59% between 40 and 79 years of age. From the prevalence of antibodies in different age groups the annual infection risk, i.e, the risk of a non-immune person acquiring toxoplasma infection, was estimated for successive age periods. The estimated annual infection risk increased from 0 . 5% in early childhood to 3% during adolescence and early adult life. Approximately 70--80% of females entered the age of reproduction without evidence of seroimmunity to toxoplasma. The risk of primary infection during pregnancy was estimated from the age distribution of parturient women in The Netherlands in 1975 and the age-specific incidence of primary infections, i.e. the incidence in the total population of susceptible and immune persons. This incidence of primary infection decreased from 1 . 62% per 9 months at the age of 17 1/2--20 years to 0 . 37% at the age of 37--45 years. The incidence of primary infections in pregnant women was estimated to be 1 . 25%.
- [Show abstract] [Hide abstract] ABSTRACT: An enzyme-linked immunosorbent assay(ELISA) was developed for the detection of toxoplasma antibodies using a single serum dilution (1:800) in conjunction with a standard curve Antigen was prepared from Toxoplasma gondii cultivated in human cell cultures. A nearly linear relationship was found between the logarithms of the absorbance values of 120 human sera at a dilution of 1/800 and the titres as determined by an end point dilution ELISA. The reproducibility of the single dilution ELISA was excellent; the coefficients of variation for within-day and day-to-day tests were less than 15%. A close correlation was found between the results obtained with ELISA, indirect immunofluorescence (IF), and complement fixation (CF). The titres in ELISA were 20 to 40 times higher than in IF and 200 to 1000 times higher than in CF.
- [Show abstract] [Hide abstract] ABSTRACT: Rubella virus was capable of replicating in both unstimulated and phytohemagglutinin-stimulated cultures of human mononuclear blood cells. Monocyte-derived macrophages were the main cell type responsible for viral replication. The susceptibility of macrophages increased during cultivation. Phytohemagglutinin-stimulated lymphocytes were able to support replication to a limited degree. No viral replication was detected in unstimulated lymphocytes. Both stimulation and viral replication in phytohemagglutinin-treated lymphocyte cultures were enhanced by the addition of murine macrophages. Human leukocyte interferon depressed the production of virus in these combined cultures. The finding that rubella virus is able to replicate in human lymphocytes as well as in macrophages may contribute to understanding the mechanisms of the suppressive effect of the virus on in vitro lymphocyte phytohemagglutinin responsiveness and in vivo immune functions.
- [Show abstract] [Hide abstract] ABSTRACT: Poliovirus was shown to suppress the in vitro response of human mononuclear blood cells stimulated with phytohaemagglutinin (PHA), pokeweed mitogen (PWM), tuberculin purified protein derivative (PPD) or allogeneic cells. The suppression required infectious virus and the presence of macrophages. Experiments with combined cultures of human lymphocytes stimulated with PHA, PWM, PPD or allogeneic cells, and different numbers of autologous macrophages indicated that both lymphocyte stimulation and the inhibitory effect of poliovirus increased with increasing ratio of macrophages to lymphocytes. The response of human lymphocytes to PHA also was enhanced when autologous macrophages were replaced with murine macrophages. Mouse hepatitis virus inhibited this enhancing effect whereas poliovirus failed to do so. The findings confirm our previous suggestion that poliovirus inhibits stimulation of lymphocytes by suppressing the enhancing effect of macrophages.
Article: [Therapy of toxoplasmosis].
Radboud University Nijmegen
Nymegen, Gelderland, Netherlands
- Department of Medical Microbiology