Detection of IgG antibodies specific for measles virus by enzyme-linked immunosorbent assay (ELISA)

Whole blood samples as an alternative to serum for detection of immunity to measles virus by ELISA

The aim of this study was to evaluate enzyme linked immunosorbent assay (ELISA) as a testing strategy for detection of antibodies against measles virus from microquantities of blood soaked onto filter paper. We studied 165 healthy children in the age group of 1 to 2 years, attending the outpatient department of pediatrics. Two sets of samples were collected from each child. One by venipuncture and the other on Whatman filter paper-3 discs of 20 mm size by finger or heel prick so that each strip is completely soaked with blood on both sides. These were tested for measles virus antibodies by ELISA using Melotest measles IgG commercial ELISA kit manufactured by Melotec S. A. (Barcelona, Spain). The resulting sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the filter paper (FP) ELISA compared to serum ELISA was 100, 90, 97.8, and 100%, respectively. The correlation coefficient r = 0.93% (p < 0.001) and the agreement between the two techniques was 98% as calculated by the Kappa statistical method. The present study has found filter paper testing by ELISA to be a promising qualitative technique for detection of immunity against measles.

[Seroprevalence of measles antibodies in a pediatric population from Botucatu, São Paulo State, Brazil]

A study of the seroprevalence of measles antibodies was conducted in a population of children residing in Botucatu, SP, in order to asses their immunological status whether induced by natural infection or by vaccination. A total of 101 children were studied, all of which had been vaccinated against measles. The laboratory tests used to determine the presence of antibodies in the collected blood samples were hemagglutination inhibition (HI) and immunoenzymatic assay (ELISA). HI results showed that 92.1% of the samples presented antibodies against measles. Samples with titers <1:4 when studied by HI were retested by ELISA in the same laboratory and only two continued to be negative for measles antibodies. Thus, measles antibodies were present in 98% of the serum samples from the children studied.

Detection and titration of measles virus antibody by hemagglutination inhibition and by dot immunobinding

Measles continues to be a major disease of both human and nonhuman primates. The dot immunobinding assay, a modified enzyme immunoassay, permits the detection of measles virus antibody in the nonlaboratory setting with either serum or whole blood collected on filter paper.

Enzyme-linked immunosorbent assay (ELISA) for measles antibody. A comparison with haemagglutination inhibition, immunofluorescence and plaque neutralization tests

An enzyme-linked immunosorbent assay (ELISA) for measles antibodies was compared with Plaque Neutralization (PRN), Haemagglutination inhibition (HI) and Fluorescent antibody (IFA) tests in 181 sera from vaccinated children and umbilical cord. Of 179 positive samples by the sensitive PRN, only two, with titers of 8, were negative by ELISA (copositivity of 98.9%). IFA and HI presented, respectively, copositivities of 93.3% and 82.7%. The ELISA presented a high sensitivity as well as a good reproducibility and represents an alternative for the time consuming PRN for detection of low measles antibodies.

Simplified enzyme-linked immunosorbent assay for specific antibodies to respiratory syncytial virus

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.

Detection of IgG antibodies to measles virus using monoclonal antibodies for antigen-capture in enzyme immunoassay

An enzyme immunoassay (EIA) for the detection of IgG antibodies to measles viral hemagglutinin (H) has been developed. Monoclonal antibodies were employed as antigen-capture reagents on a polystyrene ball solid phase. The antigen-capture EIA was significantly more sensitive than hemagglutination inhibition (HAI) and somewhat more sensitive than indirect immunofluorescence and indirect EIA for the detection of antibodies to measles virus. The importance of selecting a monoclonal antibody with a high binding affinity, and controlling for non-specific adherence of antigen or antibodies to the solid phase were demonstrated. This method offers not only greater sensitivity than HAI, but also the practicality of reagents capable of standardization and long term storage.

Enzyme-linked immunosorbent assay for evaluation of immunity to measles virus

An enzyme-linked immunosorbent assay for the determination of immunity to measles virus was developed and standardized; it was compared to the hemagglutination inhibition and plaque reduction neutralization methods for sensitivity and specificity. The conditions of the enzyme-linked immunosorbent assay were adjusted such that groups of susceptible and immune individuals were clearly separable on the basis of the reactivity of a single (1:100) dilution of their sera to viral and control antigens. The range of values corresponding to susceptibility and immunity was defined by using the distribution of values observed from testing sera obtained from susceptible and immune control groups. The enzyme-linked immunosorbent assay was then applied in a study of measles vaccinees and found to be more sensitive than the hemagglutination inhibition method and equal in sensitivity to the plaque reduction neutralization method. The three methods were equal in specificity. Thus, the measles virus enzyme-linked immunosorbent assay is a rapid, reproducible, sensitive, and specific method for screening for the presence of measles antibody.

Rapid diagnosis of measles using enzyme-linked immunosorbent assay for measles immunoglobulin M

An enzyme-linked immunosorbent assay (ELISA) for measles-specific immunoglobulin M (MIgM) was developed for use as a rapid diagnostic test for acute measles. A titer greater than or equal to 1:20 in both the acute and convalescent sera was present in 100% of patients with measles and was diagnostic of acute measles infection in children. Interference by rheumatoid factor (RF) was avoided by pretesting sera for RF and absorption with aggregated gamma globulin. Ion exchange separation of IgM and IgG should eliminate RF interference. The ELISA MIgM assay can easily be used in any laboratory for the serologic confirmation of measles infection.

Enzyme-linked immunosorbent assay for detection of measles antibody

An enzyme-linked immunosorbent assay (ELISA) was developed for the detection of measles immunoglobulin G antibody (MEASELISA). This assay was found to be comparable to the measles hemagglutination inhibition (HAI) test. Approximately 500 sera from three centers were tested by MEASELISA and the HAI test. MEASELISA demonstrated values of greater than 99% for sensitivity, specificity, and accuracy. Values were very precise, with a mean coefficient of variation of 5.4%. MEASELISA values were shown by linear regression analysis to increase as HAI titers increased. A coefficient of determination of 1.00 was obtained from test center three. MEASELISA values were found to be linearly related (r2 greater than 0.97) to MEASELISA titers, thus enabling quantitation of measles antibody from a single value. Also, data are presented that show MEASELISA to be equivalent to complement fixation for evaluating paired sera for the presence of a significant increase in antibody levels to measles virus.

Radioimmunoassay for the detection of virus-specific IgA antibodies in saliva

The use of a sensitive and versatile radioimmunoassay (RIA) for detection of mumps-specific IgA and measles-specific IgA in unconcentrated saliva samples is described. The samples were obtained either by expectoration or by swabbing of the oral cavity, with or without stimulation of secretion, and were inactivated and clarified before testing. Mumps-specific IgA antibodies were detected as early as one day after onset of illness and peaked at 1-2 weeks after onset. Measles-specific salivary IgA antibodies were detected in 15-month old children 2-3 weeks after immunization. These results suggest that the RIA technique may be useful for early diagnosis of viral infections and for confirmation of response to immunization without the need for a blood sample, as well as for the study of the secretory immune response in very young and older subjects.

Enzyme-linked immunosorbent assay (ELISA) for detection of herpes simplex virus-specific IgM antibodies

Herpes simplex virus (HSV)-specific IgM in human serum could be detected by a microplate enzyme-linked immunosorbent assay, using extracts of HSV-infected cells as antigen. Peroxidase-conjugated anti-human IgM was used to detect human IgM bound to viral antigen. Pretreatment of sera with protein A-bearing staphylococcus or with aggregated human IgG was necessary to eliminate false-positive results caused by the presence of rheumatoid factor. Specificity controls included sera of patients with other herpes group virus infections.

Detection of measles IgM antibodies by enzyme-linked immunosorbent assay (ELISA)

An enzyme-linked immunosorbent assay (ELISA) for the detectors of IgM antibodies in serum during acute or recent measles infections is described. False positive reactions due to rheumatoid factors (RF) were not observed in the test of human sera to which were added sera containing RF. Monospecific antisera against the haemagglutinin, nucleoprotein and polymerase of measles virus were used in a blocking IgM ELISA, revealing a sensitive method for the detection of the antibodies that take part in the immune reactions. An ELISA for the detection of measles-specific IgG in order to reveal IgM or IgG antibodies in the human sera is also described.

Comparison of enzyme-linked immunosorbent assay for acute measles with hemagglutination inhibition complement fixation, and fluorescent-antibody methods

An enzyme-linked immunosorbent assay (ELISA) using commercially available reagents was compared with standard serological tests for determination of antibody titers in patients with acute measles. The measles-specific ELISA was as sensitive as complement fixation, hemagglutination inhibition, and indirect fluorescent-antibody methods. The ELISA method used was simple, sensitive, inexpensive, and reproducible and may conveniently be used in a small clinical laboratory.

A rapid immunoperoxidase assay for determination of IgG antibodies to measles virus

A new indirect peroxidase antibody to membrane antigen (IPAMA) technique for the detection of IgG specific antibodies against measles virus is described. The technique utilizes as antigen measles-infected Vero cells dried on glass slides and stored at --70 degrees C. Sera of 509 healthy medical students and laboratory workers and 24 sera of measles, encephalitis, and subacute sclerosing panencephalitis (SSPE) patients were checked by IPAMA and the results have been compared with the results obtained by the hemagglutination-inhibition (HI) test. There is good agreement between the results of both techniques as to the presence or absence of antibody in 48 out of the 50 tested. The advantages of the techniques are discussed.

Enzyme-linked immunosorbent assay for the detection of influenza type-specific antibodies

An enzyme-linked immunosorbent assay (ELISA) using a purified ribonucleoprotein antigen is described for detection of type-specific anti-influenza virus antibodies. ELISA was found to be more sensitive than indirect immunofluorescent and complement fixation tests. A significant increase in antibody titer could be demonstrated by ELISA between serum specimens collected prior to and during the influenza season. ELISA appears to be useful for rapid and sensitive diagnosis of influenza infections.