Enzyme-linked Immunotransfer Blot Research Articles

Neurocysticercosis- An overlooked tropical disease

Introduction. Background: Neurocysticercosis (NCC), a parasitic disease caused by the pork tapeworm Taenia solium (T. solium), is a significant public health concern in endemic countries. It is estimated to contribute to roughly 30% of all epilepsy cases and leads to chronic morbidity in nearly 70% of affected patients. This study aimed to determine the prevalence of anti-cysticercus antibodies to T. solium in individuals with recent-onset seizures. We employed two serological techniques: Enzyme-Linked Immuno Sorbent Assay (ELISA) and Enzyme-Linked Immuno Transfer Blot (EITB). Materials and Methods: A total of 100 serum samples were collected: 50 from patients experiencing recent-onset seizures (cases) and 50 from age-matched healthy controls. All samples were analyzed for the presence of anti-cysticercus antibodies to T. solium. Results: Among the 50 cases, EITB detected anti-cysticercus antibodies in six patients (12%), while ELISA identified antibodies in three patients (6%). Notably, only two cases tested positive using both EITB and ELISA. In the control group, one individual was seropositive by EITB, and none were positive by ELISA. Conclusion: This study underscores the critical role of implementing high-quality screening methods, employing a vigilant diagnostic approach, and taking prompt preventive measures to mitigate the burden of morbidity associated with NCC.

57-Year-Old Man With Headache, Vomiting, and Gait Instability

57-Year-Old Man With Headache, Vomiting, and Gait Instability

Imaging correlates of serum enzyme-linked immunoelectrotransfer blot (EITB) positivity in patients with parenchymal neurocysticercosis: results from 521 patients.

The presence of perilesional edema among patients with parenchymal neurocysticercosis (pNCC) of various lesion subtypes has not been correlated with results of serum enzyme-linked immunotransfer blot (EITB) for cysticercal antibodies. In total, 521 patients with pNCC were classified into solitary cysticercus granuloma (SCG), multiple lesions, at least one of which was an enhancing granuloma (GMNCC), solitary calcified cysticercal lesion (SCC) and multiple calcified cysticercal lesions (CMNCC). The proportion of EITB positivity among each lesion subtype and its association with perilesional edema were determined. There were significantly higher positive EITB results in patients with GMNCC (90/111, 81.1%) compared with other lesion types. Perilesional edema was associated with positive EITB in patients with CMNCC. On univariate analysis, perilesional edema and GMNCC were associated with EITB positivity. On multivariate analysis, only GMNCC (OR 7.5; 95% CI 3.5 to 16.2) was significantly associated with EITB positivity. In patients with pNCC, the presence of perilesional edema is associated with a higher probability of a positive EITB result in patients with CMNCC, suggesting a synchronicity in the mechanisms associated with formation of perilesional edema and the antibody response in this subtype. In patients with enhancing granulomas, edema is not an independent predictor of a positive EITB, suggesting that the enhancement itself is associated with a strong antibody response.

Updates on the management of neurocysticercosis.

The goal of this review is highlight recent developments regarding neurocysticercosis, including recently developed guidelines. Recent diagnostic criteria highlight the importance of neuroimaging in establishing a diagnosis. Monoclonal antibody-based antigen detection and the enzyme-linked immunotransfer blot can be confirmatory. Management should be guided by the form of disease. Single enhancing lesions and one to two viable parenchymal cysticerci can be treated with short courses of albendazole and corticosteroid. Multiple parenchymal lesions should be treated with the combination of corticosteroids, albendazole, and praziquantel. Ventricular cysticerci should be removed when possible, often by minimally invasive surgery. Subarachnoid cysticercosis often requires prolonged courses of antiparasitic and anti-inflammatory treatment. Neurocysticerocis represents a spectrum of disease that is a common cause of neurologic disease worldwide. Management needs to be guided by the number and location of the parasites and the host response.

Neurocysticercosis - A Journey from Pre-independence to Modern India

Neurocysticercosis (NCC) is infestation of the human brain by the larva of worm, Taenia solium and is the most prevalent central nervous system (CNS) helminthiasis. The disease is widespread in tropical and subtropical regions of the world, including the Indian subcontinent, China, Sub-Saharan Africa, Central and South America and contributes substantially to the burden of epilepsy in these areas(1) . CNS involvement is seen in 60-90% of systemic cysticercosis. About 2.5 million people worldwide are infected with T. solium, and antibodies to T. solium are seen in up to 25% of people in endemic areas(1-3) . A higher prevalence of epilepsy and seizures in endemic countries is partly because of a high prevalence of cysticercosis in these regions. Seizures are thought to be caused by NCC in as many as 30% of adult patients and in 51% of children in population based endemic regions (2) . About 12% of admissions to neurological services in endemic regions are attributed to NCC and nearly half a million deaths occurring annually worldwide can be attributed directly or indirectly to NCC (Bern et al.). Punctate calcific foci on CT scan are a very common finding in asymptomatic people residing in endemic areas, found in 14-20 % of CT scans. Both seizures and positive cysticercus serology are associated with the detection of cysticerci on CT scans. Seroprevalence using a recently developed CDC- based enzyme-linked immunotransfer blot (EITB) assay is estimated at 8-12% in Latin America and 4.9-24% in Africa and South-East Asia. It is estimated that 20 million people harbour neurocysticercosis worldwide(1).

Detection ofTaenia soliumAntigens and Anti–T. soliumAntibodies in Paired Serum and Cerebrospinal Fluid Samples from Patients with Intraparenchymal or Extraparenchymal Neurocysticercosis

Neurocysticercosis (NCC) is a frequent cause of epilepsy worldwide. Compared with the more common parenchymal brain cysts, extraparenchymal infections are difficult to manage and have a poor prognosis. Serological assays are used to detect circulating Taenia solium antigens or anti-T. solium antibodies in serum or cerebrospinal fluid (CSF) samples. There are no guidelines on whether to use serum or CSF specimens for a particular assay. We obtained paired serum and CSF samples from 91 patients with NCC (48 had intraparenchymal NCC, and 43 had extraparenchymal NCC) for detection of antibodies, using an enzyme-linked immunotransfer blot (EITB) assay, and antigens, using a monoclonal antibody-based enzyme-linked immunosorbent assay (ELISA). For the intraparenchymal NCC group, the EITB assay yielded more true-positive results for serum samples, and the ELISA yielded slightly more true-positive results for CSF samples than for serum samples, but none of these differences were statistically significant. Most patients with calcified NCC were antibody positive but antigen negative. For extraparenchymal disease, all samples were antibody positive, and all but 2 were antigen positive, with most samples containing high antigen levels. The sensitivity of antibody-detecting EITB assays is not increased through the use of CSF samples rather than serum samples. The antigen-detecting ELISA performed better for CSF samples than for serum samples, but for both specimen types it was less sensitive than the EITB assay. Active and inactive NCC are better differentiated from each other by the antigen-detecting ELISA, for both serum and CSF samples. High antigen levels suggest the presence of subarachnoid NCC.

Expression of cathepsin L gene of fasciola gigantica in different developmental stages

5 Abstract: Fascioliasis is one of the most serious parasitic infestations of livestock. It is caused by Fasciola he patica (Temperate re gions) and Fasciola gi gantica (Tropical re gions).It also has a zoonotic importance. The proteolytic enzyme; ca thepsin-L cysteine proteinase (28-28.5 KDa) h elps the parasite in tissue i nvasion, host immune evasion and nutrients intake. This study aimed to check weather Fasciola gigantica flukes d epend upon cathepsin-L throughout t heir life c ycle in snail and mammalian hosts or n ot. For th at ca thepsin-L gene was inv estigated in adult and other d evelopmental stages o f Fasciola gi gantica using semi-quantitative RT-PCR assay. C athepsin-L protein w as d etected by us ing Sodium dodecyl sulphate- polyacrylamide gel electrophoresis (SDS-PAGE) anal ysis and detection of cathepsin-L cys teine proteinase antigen in examined stages by Enzyme linked immunotransfer blot (EITB) analysis. Stages of Fasciola gi gantica were collected from an experimental l ife cycle that wa s c ompleted in our la boratory. The adult worms a nd eg gs were c ollected f rom bile d ucts and gal l bladders, respectively, of slaughtered naturally infected cattle at El-Shohada abattoir, Minufiya governorate, Egypt. The results obtained revealed that ca thepsin-L gene is expressed in adult and other d evelopmental stag es o f F asciola gigantica wi th a molecular weight of 28-28.5 kDa. These results may be promising for developing an effective and reliable method for e arly diagnosis of Fasciola gi gantica and protection cysteine proteinase enzyme of Fasciola gigantica is present in ad ult and other developmental stages with m olecular weight at 28-28.5 kDa and its gene is fully expressed in adult and other d evelopmental stag es.

Evaluation of Snail Derived Antigens of Fasciola gigantica for Serodiagnosis of Human Fasciolosis

Serum samples collected from a total number of twenty parasitologically confirmed cases of human fasciolosis were used to evaluate the diagnostic sensitivity and specificity of snail derived antigens; non infected snail (SA), infected snail (ISA), redia (RA), cercaria (CA) and encysted metacercaria (EMCA) of F. gigantica using the enzyme linked immunosorbent assay (ELISA) and enzyme linked immunotransfer blot (EITB). ELISA results showed that the highest level of sensitivity (100%) was with the CA as compared with ISA, RA and EMCA which displayed lower sensitivity levels of 30, 60 and 90%, respectively. All fasciolosis patients were seronegative with SA. Sodium dodecyle sulfate polyacrylamide gel electrophoresis and EITB (with rabbit antiserum raised against F. gigantica somatic antigen) of the snail derived antigens were carried out to characterize their protein profiles and detect cross-reactive polypeptide bands between them. The immunoblot profile of SA displayed cross-reactive bands at 61 and 30 kDa with ISA, RA, CA and EMCA; CA at 61, 34 and 30 kDa with ISA; 96, 61, 34, 30 and 23 kDa with RA and 61, 34, 23 and 19 kDa with EMCA. Cross reactive antigens may be important as possible candidates for vaccine and diagnosis of fasciolosis. Immunoblot of sera from fasciolosis patients using fractionated cercarial antigen on nitrocellulose strips showed that all sera recognized common reactive band at 32.5 kDa molecular weight from cercarial antigen. We suggest that the 32.5 kDa component of Fasciola cercarial antigen may be the most sensitive and specific for the diagnosis of human fasciolosis.

Active epilepsy as an index of burden of neurocysticercosis in Vellore district, India

To determine the contribution of neurocysticercosis (NCC) to the causation of active epilepsy (AE) in a south Indian community. We conducted a door-to-door survey of 50,617 people between the ages of 2 and 60 years in a rural (38,105 people) and urban setting (12,512 people) in the Vellore district of the south Indian state of Tamil Nadu to identify patients with AE. Patients with AE were investigated with a contrast-enhanced CT scan and serologic study using enzyme-linked immunotransfer blot (EITB) for cysticercal antibodies. We identified 194 patients with AE. The prevalence of AE was 3.83 per 1,000 people, with the prevalence in the urban clusters more than twice that in the rural clusters (6.23 vs 3.04 per 1,000) (p < 0.0001). A diagnosis of NCC was made in 46 (28.4%) of the 162 patients undergoing a CT scan, and EITB was positive in 21 (13%) patients. Overall, 55 (34%) patients were diagnosed with NCC (11 definitive NCC and 44 probable NCC). There was no significant difference in the prevalence of NCC causing AE in the urban (1.28 per 1,000) and rural (1.02 per 1,000) communities. NCC is the cause of nearly one-third of all cases of AE in both the urban and rural regions. Extrapolating our results to the country as a whole leads to an estimated disease burden of 1 million patients in India with AE attributable to NCC.

Evaluation of Enzyme-linked Immunotransfer Blot for the Immunodiagnosis of Human Fascioliasis Using Cysteine Proteinase Antigen

Evaluation of Enzyme-linked Immunotransfer Blot for the Immunodiagnosis of Human Fascioliasis Using Cysteine Proteinase Antigen

Evaluation of cercarial antigen for the serodiagnosis of fasciolosis in experimentally and naturally infected sheep

The value of cercarial antigen for diagnosis of experimental and natural sheep fasciolosis was studied by enzyme linked immunosorbent assay (ELISA) and enzyme linked immunotransfer blot (EITB). In ELISA, the antibody levels of experimentally infected sheep with Fasciola gigantica appeared at 2 weeks post infection (PI), gradually increased till 7 weeks PI and nearly remained at the same level from 7 to 13 weeks PI (the end of experiment). Also, the sensitivity and specificity of cercarial antigen for diagnosis of naturally sheep fasciolosis were 100 and 90%, respectively. In EITB, in the sheep experimentally infected with F. gigantica, the band of 32.5 kDa molecular weight polypeptide appeared at 2 weeks PI and continued till the end of experiment. Also, the cercarial antigen recognized 32.5 kDa molecular weight band with all sera from naturally infected sheep with fasciolosis ( n=25). This band did not cross-react when tested with sera from infected sheep with Cysticercus tenuicollus ( n=20). This study suggests that, the 32.5 kDa molecular weight polypeptide could be used as sensitive and specific epitope for the serodiagnosis of sheep fasciolosis.

Analysis of Fasciola sp. antigen by enzyme-linked immunotransfer blot using sera from experimentally and naturally infected cattle.

Soluble polypeptides extracted from adult Fasciola sp. were analysed by SDS-PAGE, and their antigenicity was characterized by enzyme-linked immunotransfer blot (EITB) using sera from experimentally and naturally infected cattle. Polypeptides of adult Fasciola sp. with estimated molecular mass of 64-52 kDa, 38-28 kDa, 17 kDa, 15 kDa, 13 kDa and 12 kDa, were recognized by sera obtained in both early and late stages of infection. Furthermore, two polypeptides of more than 160 kDa were detected by sera only in the early stage of infection. The results of EITB using sera of dairy cows naturally infected with Fasciola sp. suggest that polypeptides of 64-52 kDa may be candidates as serodiagnostic antigen of bovine fascioliasis.

Production and characterization of monoclonal antibodies against a highly immunogenic fraction of Entamoeba histolytica (NIH:200) and their application in the detection of current amoebic infection.

Six monoclonal antibodies (MAbs) were produced against a highly immunogenic fraction derived by the chromatographic separation of the soluble preparation of axenic Entamoeba histolytica (strain NIH:200) trophozoites. Isotype characterization of the six MAbs revealed that four belonged to the IgM class and one each to the IgG1 and the IgG2a subclasses. The immunoreactivity patterns and the specificity of the MAbs with homologous and heterologous antigens were analyzed by the enzyme-linked immunotransfer blot technique and by the enzyme-linked immunosorbent assay. The MAbs reacted intensely with isolates of E. histolytica (strain NIH:200 as well as a local isolate MX1) but showed no reactivity with Entamoeba coli, Iodamoeba butschlii, Endolimax nana, Entamoeba hartmanni, free-living amoeba (Acanthamoeba harticolus) and other enteric parasites. Using the IgG1 MAb as a detecting antibody, a polyclonal-monoclonal antibody-based enzyme-linked immunosorbent assay was developed for the detection of E. histolytica antigens in stool samples of infected patients. The detection limit of the assay was 8 ng of amoebic antigen. This test was found to be specific and sensitive and yielded 100% positive results in cases with amoebiasis but did not react with controls included in the evaluation. The MAb-based enzyme-linked immunosorbent assay developed in this study will be an important test for the diagnosis of E. histolytica in the feces of infected humans; however, the limitation of the test is the inability to discriminate the pathogenic status of the amoeba detected in the stool.

Detection of stable diagnostic antigen from bile and feces of Fasciola hepatica infected cattle

Diagnostic antigens in bile and feces from Fasciola hepatica infected cattle were detected and characterized by enzyme-linked immunotransfer blot (EITB) techniques. As sources of antigen, samples of bile, intestinal contents and feces were collected from five uninfected calves and from 10 calves with known Fasciola hepatica burdens. A band detected by EITB using a densitometer in the area corresponding to 26 kDa reacted with rabbit anti-fresh fluke antigen and infected cattle sera but not with fluke-negative rabbit sera, rabbit anti- Fasciola hepatica egg sera, Fascioloides magna positive or negative cattle sera. This band was not detected by Coomassie blue in sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) gels or by Ponceau-S stained nitrocellulose strips. Band groups located at 104-66, 66-42, 42-26 and 25-16 kDa reacted inconsistently with the above sera. Sera from mice hyperimmunized with Fasciola hepatica excretory-secretory (ES) products detected only the 26 kDa band by EITB, without cross-reactivity with bands in the other molecular weight (MW) ranges. The results suggest that the 26 kDa antigen may consist of a stable component of ES products and/ or tegument-related worm antigen. Diagnosis of Fasciola hepatica through detection of specific, stable antigens in feces of infected animals offers potential advantages over serum-based tests of better sample accessibility, discrimination between previous and current infections, and possible semi-quantitation of fluke burdens.

Isolation of two Giardia lamblia (WB strain) clones with distinct surface protein and antigenic profiles and differing infectivity and virulence.

To determine the relationship between antigenic profiles and pathogenicity among Giardia lamblia clones (WB strain), trophozoites were cloned by the technique of limiting dilution. The phenotype of each clone was determined by an indirect immunofluorescence test using a polyclonal rabbit anti-G. lamblia trophozoite serum made against the parent strain. Two clones were chosen for further studies: a highly fluorescent clone, F+, in which more than 95% of the trophozoites fluoresced, and a low-fluorescence clone, F-, in which fewer than 5% fluoresced. Sodium dodecyl sulfate-polyacrylamide gradient gel electrophoresis and enzyme-linked immunotransfer blot studies of the membrane fractions of the two clones and parent strain revealed differences in both the total protein and antigenic profiles. A serum cytotoxicity test with the polyclonal serum showed that the F+ clones were more susceptible to immobilization and killing, while the majority of cells of the F- clones were resistant to such killing. Assessment of the infectivity of the two clones in the Mongolian gerbil animal model indicated that the F- clone more readily initiated infections, produced more cysts, had a higher intestinal trophozoite load, and produced a more severe clinical syndrome, while the F+ clone was less phenotypically stable in vivo and in some cases took longer to be cleared from the intestine.

Production of monoclonal antibodies to Naegleria fowleri, agent of primary amebic meningoencephalitis

Monoclonal antibodies (MAbs) to Naegleria fowleri, the etiologic agent of primary amebic meningoencephalitis (PAM), have been produced and used as probes to identify N. fowleri amebae in brain sections of patients who died of that disease. These MAbs were characterized for their specificity by the indirect immunofluorescence assay (IIF), dot immunobinding assay (DIBA), and enzyme-linked immunotransfer blot technique (EITB). The MAbs reacted intensely with all strains of N. fowleri tested originating from different geographic areas in the IIF and DIBA tests, but showed no reactivity with four other species of Naegleria, N. gruberi, N. jadini, N. lovaniensis, and N. australiensis, or a strain of Acanthamoeba castellanii. In the EITB assay the MAbs reacted with the antigens of N. fowleri and produced intensely staining bands at the 160-, 104-, 93-, and 66-kilodalton (kDa) regions and several minor bands at the 30- and 50-kDa regions. The MAbs also reacted with the antigens of N. lovaniensis and produced a darkly staining band at 160 kDa and a diffusely staining band at 116 kDa, indicating that these antigens were shared by the two species. The MAbs, however, showed no reactivity with N. jadini and N. gruberi in the EITB assay.

Identification of a genus-specific Schistosoma mansoni soluble egg antigen reactive with the serum of infected patients.

The ability of serum samples obtained from humans with schistosomiasis mansoni to recognize Schistosoma mansoni soluble egg antigens (SmSEA) was assessed by the enzyme-linked immunotransfer blot (EITB) method. The sera from 15 infected patients before and 2 years after treatment with oxamniquine (n = 30) recognized bands ranging in molecular weight from 9 to 200 Kd. A 31 Kd component of SmSEA was recognized by all infection sera, but not by normal human serum. The sera from 2 humans infected with S. haematobium and 2 with S. japonicum also recognized the 31 Kd band present in SmSEA, whereas those from 2 humans infected with Fasciola hepatica did not. The 31 Kd antigen was isolated by electrophoresing SmSEA through a 15% SDS-acrylamide gel, followed by excision and electroelution of the 31 Kd band. The purified 31 Kd was used in conjunction with ELISA at a concentration of 1 microgram/ml to confirm the apparent genus specificity of this protein. Thus, the sera of patients infected with S. mansoni, S. haematobium, or S. japonicum were clearly reactive in ELISA, whereas normal human serum or sera from patients with F. hepatica were negative. In conclusion, the 31 Kd protein appears to be a good candidate for developing a screening assay for the immunodiagnosis of schistosomiasis.

Structure of the hepatitis A virion: peptide mapping of the capsid region.

Milligram amounts of highly purified hepatitis A virus (HAV) were obtained from persistently infected cell cultures. The HAV polypeptides were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and transferred to nitrocellulose for detection by an enzyme-linked immunotransfer blot procedure. The HAV nucleotide-derived amino acid sequence was subjected to computer analysis to identify potential immunogenic regions within the HAV capsid polypeptides. Synthetic peptides corresponding to selected regions of each of the larger putative capsid polypeptides were coupled to keyhole limpet hemocyanin and used to immunize rabbits. Four of six anti-HAV peptide sera were strongly reactive. Antipeptide serum generated against amino acids (a.a.) 75 through 82 reacted with the 27,000-molecular-weight (MW) polypeptide; serum against a.a. 279 through 285 reacted with the 29,000-MW HAV polypeptide; and sera against a.a. 591 through 602 and 606 through 618 reacted with the 33,000-MW HAV polypeptide. These reactions enabled the identification of the gene order of the larger HAV P1 region gene products. Our data indicate the following molecular weights: HAV VP2 or 1B, 27,000; HAV VP3 or 1C, 29,000; and HAV VP1 or 1D, 33,000.

Identification of functional Fasciola hepatica antigens in experimental infections in rabbits.

Studies done comparing the reactivity of serum from an infected rabbit at different intervals of infection with a Fasciola hepatica crude tegument extract, F. hepatica excretory-secretory (ES) products and Fh arc 2 by ELISA show that the first 2 antigen preparations offer a better sensitivity for detecting acute infection, especially in its early stages (3 weeks). The ES proteins from F. hepatica adult worms were identified by the enzyme-linked immunotransfer blot (EITB) in order to define the antigens recognized by the sera from rabbits with experimental fascioliasis. A group of 7 polypeptides with molecular weights of 23-28 Kd were the major antigens recognized. Reactivity to these antigens is maximum at 8-10 weeks of infection by EITB. As the infection progresses, reactivity to the 23-28 Kd antigens decreases but does persist through 52 weeks of infection. At least 5 other polypeptides of 120, 84, 58, 52, 39 and 33 Kd were recognized by the sera of infected rabbits from 6 to 52 weeks of infection. A different pattern was observed in parallel studies done with these same sera by immunoprecipitation of ES antigens. In addition to a 33 Kd antigen, which was detected by both techniques, a 62 Kd antigen was detected early in infection (5 weeks) and 3 major antigens of 38, 40 and 44 Kd were prominent by immunoprecipitation from 9 weeks onward. This implies the presence of multiple Fasciola antigens with serodiagnostic potential. The expression of these antigens during development and their possible role in immunity is discussed.

Schistosoma mansoni adult microsomal antigens, a serologic reagent. I. Systematic fractionation, quantitation, and characterization of antigenic components.

A systematic and quantitative search was conducted to identify and isolate a serologically pertinent antigen with high specific activity and low cross-reactivity from adult worms of Schistosoma mansoni. Adult worms of S. mansoni quickly thawed from liquid N2 temperatures were disrupted by controlled homogenization in isotonic buffered sucrose. Differential centrifugation of the homogenate yielded three particulate and one soluble fractions: the 480 x G pellet (nuclear), the 7650 x G pellet (mitochondrial), the 360,000 x G pellet (microsomal), and the 360,000 x G supernatant (cytosol). Quantitative analysis indicated a major concentration of specific antigenic activities in the microsomal fraction. Further purifications of the urea-solubilized, n-butanol-treated microsomal particles by gel filtration and ionic-exchange chromatography resulted in a microsomal antigen (MAMA) possessing high specific activity and low cross-reactivity. The final purification post-ionic exchange chromatograph showed a 30-fold increase of specific antigen activity over that of the cytosol fraction. Sodium dodecyl sulfate/polyacrylamide gel electrophoresis (SDS-PAGE) and enzyme-linked immunotransfer blot by the "Western blot" technique (EITB) indicated specific antigenic activities in association with several different m.w. bands (heterogeneous m.w. by extrapolation = 4.3 to 11.9 x 10(6), 2.0 x 10(5), and 2.0 x 10(4) daltons) of the MAMA fraction. When compared with other reported serologic antigens, MAMA showed substantially higher specific activity and lower cross-reactivity.