Comparison of enzyme-linked immunosorbent assay (ELISA) and complement fixation test for detection of Mycoplasma pneumoniae antibodies.

An enzyme-linked immunosorbent assay (ELISA) for the detection of IgG and IgM antibodies against Mycoplasma pneumoniae, performed with commercial antigen and reagents, is compared with the complement fixation test (CF) in a serological study of 209 human sera. Concordant results were usually obtained by CF test and by IgG ELISA in sera from patients with recent M pneumoniae infection. In contrast, when used for an immunological survey of a general population, approximately 27% of the sera negative in the CF test were positive for IgG by the ELISA, and sera with low CF titres were found to have a broad range of IgG titre by the ELISA. This may be due to the greater sensitivity of the ELISA technique and/or to different types of antibody measured by both tests. IgM was detected by ELISA in sera from all patients with recent M pneumoniae infection diagnosed on the basis of clinical findings and by CF assay. Occasionally false-positive IgM antibodies were due to rheumatoid factor (RF); this potential interference necessitates routine testing of IgM antibody positive sera for RF.     

Enzyme-linked immunosorbent assay (ELISA) for detecting antibodies in sera of patients with adenovirus infection

The 41 distinct antigenic types of adenoviruses (Ads) are responsible for a broad spectrum of diseases in humans. We have developed an enzyme-linked immunosorbent assay (ELISA) using adenovirus (Ad) infected MRC-5 cells for detecting IgG and IgM antibodies to Ads. Using the ELISA, we detected IgG antibodies in 100% (20/20) of sera from normal adults (geometric mean titer, GMT = 1840.8, range = 40-20,480) and IgM antibodies in 3 of 20 sera (15%) with a GMT of 25.1. Our indirect immunofluorescence (IF) technique also detected IgG antibodies in 100% of these sera (GMT = 248.3, range = 40-5,120) and IgM antibodies in the 3 samples reactive in ELISA (GMT = 20.0, range = less than 5-40). In contrast, the complement fixation (CF) test detected antibodies to Ads in only 65% (13/20) of these sera (GMT = 10.9, range = less than 4-32). Moreover, IgG and IgM responses could not be distinguished using CF. Thus the sensitivity of these three techniques is greatest for ELISA. Additionally, a study of sequential sera from 3 patients with acute Ad infection disclosed seroconversion using all three methods. Both the ELISA and IF techniques permit the detection of transition from IgM to IgG, whereas CF only detects conversion from seronegativity to seropositivity. Finally, preliminary data suggest that the IgM response as measured by ELISA is specific for subgroups or types of Ad. This newly devised ELISA may be useful for detecting Ad infections.     

Enzyme-linked immunosorbent assay for mumps and parainfluenza type 1 immunoglobulin G and immunoglobulin M antibodies

A solid-phase enzyme-linked immunosorbent assay (ELISA) for detection of mumps and parainfluenza type 1 antibodies (immunoglobulin G [IgG] and IgM classes) is described and compared with the conventional complement fixation (CF) test. A highly positive correlation was found between mumps IgG ELISA and the mumps CF test, whereas parainfluenza type 1 IgG ELISA had only a moderate positive correlation with the respective CF test. Mumps IgM antibodies could be demonstrated in all patients with serologically verified and clinically typical (parotitis, meningitis, or orchitis) mumps virus infection, but not in patients with rises in parainfluenza CF titers. Mumps IgM was already present in the acute-phase sera if they were not taken during the first 2 days after onset of disease. Mumps IgM was also found in some paired sera that were taken too late to demonstrate any significant increase in the antibody titers by CF. Therefore, mumps IgM ELISA provides an improvement over the conventional laboratory diagnosis of mumps infection, since the measurement of specific IgM antibodies in a single serum by ELISA is diagnostic, rather than the identification of a fourfold or greater rise in CF antibody titer. An unexpected finding was that parainfluenza type 1 IgM antibodies could not be demonstrated by ELISA in paired sera with rises in parainfluenza CF titers, suggesting a different antibody response from that occurring in mumps infection.     

Age-related interference with Chlamydia pneumoniae microimmunofluorescence serology due to circulating rheumatoid factor.

Microimmunofluorescence (MIF) serology is commonly used in the diagnosis of chlamydial infections. In the MIF assay, Chlamydia pneumoniae elementary bodies were used to detect C. pneumoniae immunoglobulin G (IgG) and IgM antibodies in paired serum samples from 286 patients with respiratory illnesses. In 69 patients, MIF serology was compared with C. pneumoniae cultures. All C. pneumoniae cultures remained negative. However, 205 (71%) of 286 patients were C. pneumoniae antibody positive and 64 (22%) had MIF test results indicating recent infection; 11 showed a fourfold increase in IgG titer, 18 had IgG titers of greater than or equal to 1:512, and 41 had IgM titers of greater than or equal to 1:16. In 35 (55%) of 64 patients, a recent-infection diagnosis was based on C. pneumoniae IgM antibodies only. However, 78% of C. pneumoniae IgM-positive patients had circulating rheumatoid factor (RF) by rheumatoid arthritis latex assay. RF positivity increased with age. After absorption with anti-human IgG, all C. pneumoniae IgM-positive sera became C. pneumoniae IgM negative in the MIF assay. Twenty-five patients with active rheumatoid arthritis but without respiratory illness were also tested; 14 were C. pneumoniae IgG positive and C. pneumoniae IgM positive as well. Absorption of IgG from these RF-containing sera invariably resulted in disappearance of reactivity in the MIF IgM assay. We conclude that with age the serologic diagnosis of recent C. pneumoniae infection becomes increasingly prone to false-positive results unless sera are routinely absorbed prior to MIF IgM testing.     

Adenovirus infection in patients with Kawasaki disease

Two outbreaks of Kawasaki disease at different times and areas (Kyoto in 1982 and Sapporo in 1985) of Japan were studied retrospectively for the presence of antibodies to adenoviruses and herpesviruses. Only 2 of 12 (16.7%) consecutive acute phase sera of patients from the outbreak in 1982 and 1 of 10 (10.0%) sera from 1985 showed positive antibodies for the common adenovirus antigen by a complement fixation (CF) test, whereas 10 of 16 (62.5%) age- and sex-matched controls during the outbreak of Kawasaki disease in 1985 were seropositive by the CF test. In contrast, using a recently developed enzyme-linked immunosorbent assay (ELISA), 9 patients (75.0%) in 1982 and 9 patients (90.0%) in 1985 had antibodies to adenovirus type 2. In addition, 5 of 10 (50.0%) of the 1982 and 6 of 9 (66.7%) of the 1985 patients who were seronegative for CF antibodies were positive for IgM antibodies to adenovirus type 2. Fifteen (93.8%) controls were positive for antibodies to adenovirus type 2 by ELISA and only two sera showed negative CF antibodies with positive IgM antibodies to adenovirus type 2. Sequential sera from 4 patients in 1985 had either IgM or IgG antibodies by ELISA and eventually three became seropositive by the CF test in time. Additionally, no significant difference was noted with antibody status to herpes simplex virus type 1 and 2 (HSV-1 and HSV-2), varicella zoster virus (VZV), and cytomegalovirus (CMV) between patients and controls.(ABSTRACT TRUNCATED AT 250 WORDS)     

Analysis of eight commercial enzyme immunoassay tests for detection of antibodies to Mycoplasma pneumoniae in human serum

Mycoplasma pneumoniae is an important etiologic agent of primary atypical pneumonia in children and adults. The diagnosis of M. pneumoniae infection is commonly confirmed through serologic testing. In this study, we used paired sera from 51 patients (all with confirmed M. pneumoniae infection and positive complement fixation [CF] titers) to compare the results of eight enzyme immunoassays (EIAs) available commercially in the United States. We compared two single-use EIAs and six plate-type EIAs. Results from acute-phase sera ranged from only 7 (14%) positive by ImmunoWELL (GenBio) immunoglobulin M (IgM) EIA to 23 (45%) positive by Zeus IgG EIA. When both the acute-phase and convalescent-phase serum samples were examined, positive results ranged from 20 (39%) by the ImmunoWELL (GenBio) IgM assay to 45 (88%) positive by the Remel IgG-IgM EIA. In this study, the single-use EIAs by Remel and Meridian were more reliable than were the plate-type EIAs. Among the plate-type EIAs, the Zeus and DiaSorin assays (which detect antibodies to protein antigens) were more sensitive than the ImmunoWELL assay (which detects antibodies to glycolipid antigens). In general, IgG EIAs on convalescent-phase sera were more concordant with one another than were IgM EIAs with one another. Scatter plot analysis of convalescent-phase sera showed that, as the CF titer dropped, the IgM assays identified fewer positive convalescent-phase sera. In contrast, the IgG assays provided fairly consistent positive results for convalescent-phase sera with CF titers of 64 and above. Results of individual tests and overall limitations of serodiagnostics for M. pneumoniae infections are discussed.     

IgG response to Mycoplasma pneumoniae in patients with community-acquired pneumonia determined by ELISA

In a prospective study of community-acquired, radiologically verified pneumonia, a solubilized mycoplasma antigen was used in an enzyme-linked immunosorbent assay (ELISA) for the detection of IgG-antibodies to Mycoplasma pneumoniae in paired sera from 60 patients. All of the 13 patients with a positive complement fixation (CF) test for M. pneumoniae were positive in the ELISA, and 46 out of 47 patients with a negative CF test were negative. The only false positive test was recorded from a patient with a positive CF test for Chlamydia. Specific IgG antibodies were also determined in paired sera from 50 pneumonia patients, all positive in the CF test for M. pneumoniae, and collected over a period of 10 years. Of these 50 patients, 45 were recorded as positive in the ELISA for IgG antibodies to M. pneumoniae. In the prospective as well as in the retrospective study, the time for admission to hospital after onset of disease showed considerable variation (1-14 days), with the consequence that high titers were recorded in the CF as well as in the ELISA in some of the first serum samples. A tendency to earlier detection of significant titers was noted in the CF test as compared to the ELISA.     

Evaluation of chlamydial tests in early trachoma

An enzyme linked immunosorbent assay (ELISA) and an immunofluorescence (IF) test were compared with culture for their value in the diagnosis of chlamydial infection in early trachoma. Conjunctival swabs and scrapings from 81 school children with active trachoma from Khartoum, Sudan, were tested. Fourteen (17.3%) of the children with signs of active trachoma were positive by isolation. The sensitivities of the ELISA and IF tests, compared to cultures, were 85.0% and 68.2%, while the specificities for the ELISA and IF tests were 99.2% and 99.3%, respectively. Chlamydial IgM and IgG antibodies reactive with serotypes A-C and D-K of Chlamydia trachomatis were detected in sera of 28 (71.2%) of the 39 children from whom serum was obtained. Only eight of the 14 isolation-positive children were tested for chlamydial antibodies, and all of them had IgM and IgG antibodies at a titer of greater than or equal to 1:16. An IgG antibody titer of 1:16 or greater was detected in 20 (65.0%) of the 31 isolation-negative patients tested for chlamydial antibodies. The geometric mean titers of IgG antibodies to the antigen pools A-C and D-K were 132 and 42, respectively. Our study suggests that trachoma is prevalent in the child population studied. Clinical signs of active trachoma were found in 47.0% of the altogether 172 children investigated. ELISA can be recommended as a diagnostic tool in trachoma field surveys.     

Enzyme-linked immunosorbent assay for immunological diagnosis of human tularemia.

The enzyme-linked immunosorbent assay (ELISA) was applied for immunological diagnosis of human tularemia, using lipopolysaccharide from Francisella tularensis as antigen. Sera collected from patients, healthy individuals, and vaccinated volunteers were investigated for antibodies against F. tularensis by ELISA and tube agglutination. In ELISA all sera were titrated with a polyspecific anti-immunoglobulin enzyme conjugate. A limited number of consecutive sera from individual patients were also investigated for immunoglobulin G (IgG) and IgM antibodies by means of immunoglobulin class-specific conjugates. On an average ELISA was more than 10-fold as sensitive as tube agglutination. Two weeks after onset of disease, sera from patients had significantly higher titers in ELISA than sera from healthy controls. High titers persisted after more than 2 years. Significant amounts of both IgG and IgM antibodies were present within 1 to 2 weeks after infection. The antibody activity increased during the first month, without any significant change of the relation between IgG and IgM titers. After 2.5 years the IgG/IgM titer ratio of sera from patients was significantly increased. Within 6 weeks after vaccination sera from about half of the vaccinees had significantly elevated titers in ELISA. Titers observed after vaccination were generally lower than those found after infection. An elevated ELISA titer can be of diagnostic importance by the end of the first week of illness. A significant increase of titer in consecutive serum samples indicates a diagnosis of tularemia. Determination of IgG and IgM antibodies may be of value in determing whether a positive titer of a single serum sample is of longstanding or recent origin.     

Detection of antichlamydial immunoglobulin G and M antibodies by enzyme-linked immunosorbent assay

Chlamydia trachomatis causes a wide range of infections in adults and conjunctivitis and pneumonia in neonates. The complement fixation test for chlamydial antibody is broadly reactive, but possesses low sensitivity, whereas the microimmunofluorescence test is highly sensitive, but technically difficult to perform. A simple, rapid enzyme-linked immunosorbent assay (ELISA) has been developed for the measurement of immunoglobulin G (IgG) and IgM antibodies to C. trachomatis. Wells of microtiter plates were coated with Renografin-purified elementary bodies (serotype L2) grown in cycloheximide-treated McCoy cells, and serum antibody was detected with peroxidase-labeled goat antihuman IgG and IgM antibody. Of 41 sera tested from patients with lymphogranuloma venereum, pelvic inflammatory disease, cervicitis, or urethritis there was a 90 and 63% correlation of positive results for IgG and IgM, respectively, by microimmunofluorescence and ELISA. Of the positive correlates, ELISA titers were up to 128 times higher than microimmunofluorescence titers for IgG and IgM. The ELISA detected no false-positive results, but missed two positive results for IgG. Both of these sera were reactive against serotypes C and J, suggesting that the ELISA with LGV L2 antigen may not measure antibodies to serotypes within the C serogroup. The IgM ELISA detected 7 negative and 4 positive results not detected by the microimmunofluorescence test. Of four paired sera examined by ELISA, three showed a fourfold rise in IgG antibody titer, and one showed a twofold rise. Further evaluation of this ELISA will be required to determine how useful it will be in seroepidemiological studies and as a diagnostic tool.     

McAb ELISA间接夹心法检测HFRS病人血清IgM和IgG抗体的研究

肾综合征出血热(HFRS)早期临床症状不典型,因此在病人血清中检出特异性抗体,特别是IgM抗体对辅助临床诊断有重要意义。此外,HFRS的流行病学监测和病原学研究等都需有敏感、特异、简便而客观的     

单克隆抗体ELISA间接夹心法检测家鼠型HFRS疫区人和动物血清中特异性抗体

用McAb-ELISA间接夹心法和IFAT或酶标SPA染色法平行检测山西地区(家鼠型HFRS疫区)的人及动物血清中HFRS病毒特异性IgM和/或IgG抗体。结果ELISA检测174份HFRS病人血清的阳性率及抗体滴度均明显高于IFAT。检测295份无明确HFRS病史的健康人血清,ELISA的阳性率也高于IFAT。检测215份鼠类血清,102份兔血清及108份猪血清,ELISA的阳性检出率与IFAT或酶标SPA染色法基本相同。用阻断试验等证明本ELISA检出的确是HFRS病毒特异性抗体。对ELISA的某些试验条件作了讨论,并认为,McAb-ELISA在帮助临床早期诊断及血清流行病学调查等方面均有实用价值。     

Diagnostic utility of ELISA test using antigen A60 in suspected cases of tuberculous meningitis in paediatric age group.

The aim of the study was evaluation of the utility of ELISA test using antigen A60 for rapid diagnosis of tuberculous menigitis (TBM) in paediatric age group. ELISA test based on mycrobacterial antigen A60 (Anda biological, France) was used to estimate specific IgM and IgG antibodies in the sera and CSF of 20 suspected cases of TBM which were selected on the basis of numerous parameters and were smear negative on concentrated smear of CSF. Sera of 20 Montoux negative healthy children was taken as control by detecting IgM and IgG antibodies to A60 antigen. Response to anti-tubercular treatment was observed in all the suspected cases of TBM. This study showed that specificity for diagnosis of TBM by detecting IgM and IgG antibodies in sera was 90% and 80% respectively. Sensitivity of the test by detecting IgM and IgG antibodies in sera was 85% and 80% respectively with positive predictive value of 89.47% for IgM antibody and 80% for IgG antibody. In CSF IgM and IgG antibodies were found in 75% and 60% cases respectively. Both were positive only in 60% of cases. It is concluded from this study that 80-85% cases of TBM in paediatric age group have eigher IgM or IgG antibodies in sera whereas 60-75% have antibodies in CSF.     

Detection of nephropathia epidemica (Puumala virus)-specific immunoglobulin M by enzyme-linked immunosorbent assay.

Nephropathia epidemica (NE), a less severe form of hemorrhagic fever with renal syndrome, is caused by Puumala virus (PUU). This communication reports the development of a mu-capture enzyme-linked immunosorbent assay (ELISA) for detection of specific immunoglobulin M (IgM) antibodies to PUU virus in human sera. Acute- and early-convalescent-phase sera (collected 1 to 41 days after disease onset) from 29 Swedish patients with clinical NE were tested for PUU virus-specific IgG and IgM antibodies by the indirect immunofluorescence test and ELISA, respectively. Late-convalescent-phase serum was also collected from 18 of these patients 3 to 24 months postinfection and assayed. The IgM ELISA values were strongly positive in sera collected during the first 2 months; at 3 to 9 months, they were negative or in the lower range of significance, and at 24 months all sera were negative. Paired sera from NE patients often fail to show seroconversion or a significant titer rise when tested by indirect immunofluorescence. Since all acute- and early-convalescent-phase sera were positive by IgM ELISA, this test could become an important tool for early diagnosis of acute human NE infections.     

New criteria for immunofluorescence assay for Q fever diagnosis in Japan

A study was made to evaluate the cutoff value of indirect immunofluorescent-antibody (IFA) test for Q fever diagnosis in Japan. We used 346 sera, including 16 from confirmed Q fever cases, 304 from Japanese pneumonia patients, and 26 from negative cases. Thirteen sera from the confirmed Q fever cases with an immunoglobulin M (IgM) titer of > or =1:128 and/or IgG titer of > or =1:256 by the IFA test were positive by both enzyme-linked immunosorbent assay (ELISA) and Western blotting assay (WBA), whereas 298 sera from pneumonia patients and 26 negative sera with an IgM titer of < or =1:16 and an IgG titer of < or =1:32 by the IFA test were negative by both ELISA and WBA. In the proposed "equivocal area," with an IgM titer of > or =1:32 and < or =1:64 and/or an IgG titer of > or =1:64 and < or =1:128, we found 9 sera, 3 from confirmed Q fever cases and 6 from Japanese pneumonia patients, by the IFA test. Three sera from the confirmed Q fever cases and one of the sera from pneumonia patients were IgM and/or IgG positive by both ELISA and WBA. These results suggest that a single cutoff value for the IFA test may cause false-positive and false-negative results. In conclusion, this study showed that an "equivocal area" should be used for the IFA test rather than a single cutoff value and that sera in the equivocal area should be tested by additional serological assays for confirmation.     

Enzyme immunoassay for Q fever: comparison with complement fixation and immunofluorescence tests and dot immunoblotting.

Enzyme-linked immunosorbent assays (ELISA) for the detection of specific immunoglobulin G (IgG) and IgM antibodies were developed by using purified Coxiella burnetii cells. Variables, including type of microtiter plate, blocking agent, incubation conditions, antigen stability, and substrate type, were examined to achieve optimal ELISA performance. The reliabilities of the assay systems were compared with those of complement fixation (CF) and enhanced immunofluorescence (EIF) tests with 600 human serum samples from defined clinical cases of Q fever, routine samples, and serum specimens from farmers. ELISA and EIF test results agreed in all cases. Dot immunoblotting was also used to test some of these sera and gave a rapid, qualitative result, which agreed with ELISA and EIF test results in all cases. No instances were found in which both ELISA and EIF test results were negative and the CF test results was positive. However approximately 5% of the sera were positive by ELISA and the EIF test while the CF test result was either negative or unreadable because of serum anticomplementary activity. We conclude that dot immunoblotting is a useful screening test, whereas ELISA and the EIF test are both rapid and sensitive tests when used for the serodiagnosis of Q fever and should be considered to be replacements for the CF test.     

Indirect immunoglobulin G (IgG) and IgM enzyme-linked immunosorbent assays (ELISAs) and IgM capture ELISA for detection of antibodies to lipopolysaccharide in adult typhoid fever patients in Pakistan.

Sera from 339 adult febrile patients in Pakistan were tested for antibodies to Salmonella typhi lipopolysaccharide by indirect immunoglobulin G (IgG) and IgM enzyme-linked immunosorbent assay (ELISA) and IgM capture ELISA. A total of 55 patients had S. typhi cultured from their blood, 20 had S. typhi cultured from their stool, 24 were blood or stool culture positive for S. paratyphi A, 41 were culture negative but clinically diagnosed as having enteric fever, 41 had gastrointestinal or urinary tract infections, 41 were clinically diagnosed as having malaria, 20 were smear-positive patients with malaria, 58 had respiratory infections, and the remaining 39 individuals were placed in a miscellaneous group who did not have Salmonella infection. The sensitivities of the indirect IgG ELISA, indirect IgM ELISA, and IgM capture ELISA determined with specimens obtained from the blood culture-positive patients with typhoid fever (positive controls) were 80, 64, and 62%, respectively. The specificities of the assays determined with sera from the patients with respiratory infections (negative controls) were 95, 95, and 97%, respectively. The percentage of smear-positive patients with malaria who were positive by these assays was lower than that in the negative control group. The percentages of individuals in the other patient categories who were positive by these tests were between those obtained with the positive and negative controls. Of the positive controls, 26 were positive by both IgM assays, 9 were IgM positive only by indirect ELISA, and 8 were IgM positive only by IgM capture ELISA. A total of 70% of the positive control patients who were tested for O agglutinins by the Widal tube agglutination assay were positive; however, 29% of the negative control patients were also positive. The indirect IgG ELISA was the single most effective test for the serodiagnosis of typhoid fever in this population.     

Analysis of complement fixation and commercial enzyme immunoassays for detection of antibodies to Mycoplasma pneumoniae in human serum

The Meridian ImmunoCard (IC), GenBio ImmunoWELL-IgM, and Remel EIA commercial antibody tests are qualitative enzyme immunoassays that detect antibodies to Mycoplasma pneumoniae in serum. These tests were compared to an M. pneumoniae complement fixation (CF) assay, which uses a commercially available antigen component. The Meridian IC and the ImmunoWELL-IgM detect immunoglobulin M (IgM) only; the Remel EIA and the CF test detect both IgM and IgG antibodies. Detection of specific IgM antibody, which appears early in infection, can be, but is not always, indicative of a recent or current infection. Paired serum samples from 64 adult patients with probable M. pneumoniae infection were examined with each of the four tests. Thirty (47%) of the 64 acute-phase sera were IgM positive by Meridian IC, 26 (41%) were positive by Remel EIA, 24 (38%) were positive by CF, and 15 (23%) were positive by ImmunoWELL-IgM. When both the acute- and convalescent-phase serum samples from each patient were examined, 61 (95%) of the 64 patients were positive by CF, 60 patients (94%) were positive by Remel EIA, 52 patients (81%) were IgM positive by the Meridian IC, and 29 patients (45%) were IgM positive by the ImmunoWELL-IgM assay. The Meridian IC was more sensitive than the other tests for early detection of IgM antibodies. However, after examining paired serum samples, we concluded that the detection of IgM alone may not be useful for all cases of mycoplasma infection, especially in an adult population.     

Contribution to laboratory diagnosis of mumps and parainfluenza

Specific IgM and IgG antibodies to mumps virus (MV) were detected in sera of mumps-patients by ELISA in agreement with the results obtained by indirect immunofluorescence (IF). Of given sera 37.5% contained IgM reacting in indirect ELISA also with the antigens of parainfluenza virus (PiV) T3. In all patients with respiratory illness over 2 years of age, the significant increase of antibodies to PiV in haemagglutination inhibition (HI) test was in good correlation with serum IgM and IgG antibody levels to PiV T3 determined by ELISA; but, in addition, 30.7% of these sera cross-reacted with MV antigens. The cross-reactions were eliminated by using MV-nucleocapsid antigen in indirect ELISA, or in direct ELISA using the peroxidase-labelled whole virion antigen. In some children under two years of age a discrepancy was observed between the significant increase of serum antibodies in HI and the inability to detect specific IgM antibodies by means of ELISA in their sera. The low-avidity antibodies appearing after primary PiV infection were probably washed off during the ELISA procedure.     

Mumps-specific immunoglobulin M and G antibodies in natural mumps infection as measured by enzyme-linked immunosorbent assay

An enzyme-linked immunosorbent assay for the demonstration of mumps immunoglobulin G (IgG ELISA) and immunoglobulin M antibodies (IgM ELISA) in serum was compared with complement fixation (CF), hemagglutination inhibition (HI), and hemolysis-in-gel (HIG) tests. The antibody levels measured by IgG ELISA had a high positive correlation with the CF and HIG tests, whereas only a moderate correlation was found between IgG ELISA and HI. Similar patterns of antibody response were observed with IgG ELISA, CF, and HIG: the antibody titres increased rapidly after the onset of symptoms and reached the maximal values in about three weeks. The HI antibodies developed more slowly during the first week of disease, after which the titres increased rapidly up to the fourth week. IgM antibodies measured by ELISA developed soon after onset of symptoms; most patients had IgM antibodies from the second day, and the highest titres were reached within the first week. The antibody response in mumps parotitis did not differ from that in mumps meningitis/encephalitis, while relatively higher antibody titres were found in patients with orchitis/epididymitis. The diagnostic efficiencies of the methods were compared with serum specimens from 33 patients who had a serologically verified mumps infection by at least one of the five methods used (rising antibody titres in paired sera or detectable IgM): IgM ELISA detected all 33 cases, IgG ELISA 29, HIG 28, HI 23, and CF 13. In 27 cases, IgM antibodies were already present in the acute phase serum specimens. It was concluded that mumps IgM ELISA is a more rapid and sensitive means for the serological diagnosis of mumps infection than the conventional tests.