scholarly journals A Modified Enzyme-Linked Immunosorbent Assay for Measurement of Antibody Responses to Meningococcal C Polysaccharide That Correlate with Bactericidal Responses

1998 ◽  
Vol 5 (4) ◽  
pp. 479-485 ◽  
Author(s):  
Dan M. Granoff ◽  
Susan E. Maslanka ◽  
George M. Carlone ◽  
Brian D. Plikaytis ◽  
George F. Santos ◽  
...  
Keyword(s):  
Immunosorbent Assay ◽  
Geometric Mean ◽  
Correlation Coefficients ◽  
Antibody Responses ◽  
Enzyme Linked Immunosorbent Assay ◽  
High Avidity ◽  
Igg Antibody ◽  
Standard Assay ◽  
Bactericidal Antibody ◽  
Antibody Titers

ABSTRACT The standardized enzyme-linked immunosorbent assay (ELISA) for measurement of serum immunoglobulin G (IgG) antibody responses to meningococcal C polysaccharide has been modified to employ assay conditions that ensure specificity and favor detection primarily of high-avidity antibodies. The modified and standard assays were used to measure IgG antibody concentrations in sera of toddlers vaccinated with meningococcal polysaccharide vaccine or a meningococcal C conjugate vaccine. The results were compared to the respective complement-mediated bactericidal antibody titers. In sera obtained after one or two doses of vaccine, the correlation coefficients, r, for the results of the standard assay and bactericidal antibody titers were 0.45 and 0.29, compared to 0.85 and 0.87, respectively, for the modified assay. With the standard assay, there were no significant differences between the geometric mean antibody responses of the two vaccine groups. In contrast, with the modified assay, 5- to 20-fold higher postvaccination antibody concentrations were measured in the conjugate than in the polysaccharide group. Importantly, the results of the modified assay, but not the standard ELISA, paralleled the respective geometric mean bactericidal antibody titers. Thus, by employing conditions that favor detection of higher-avidity IgG antibody, the modified ELISA provides results that correlate closely with measurements of antibody functional activity that are thought to be important in protection against meningococcal disease.

scholarly journals Pneumococcal Type 22F Polysaccharide Absorption Improves the Specificity of a Pneumococcal-Polysaccharide Enzyme-Linked Immunosorbent Assay

2001 ◽  
Vol 8 (2) ◽  
pp. 266-272 ◽  
Author(s):  
Nelydia F. Concepcion ◽  
Carl E. Frasch
Keyword(s):  
Correlation Coefficient ◽  
Immunosorbent Assay ◽  
Pneumococcal Vaccination ◽  
Correlation Coefficients ◽  
Enzyme Linked Immunosorbent Assay ◽  
Igg Antibody ◽  
Functional Activities ◽  
Antibody Titers ◽  
The Common ◽  
Elisa Inhibition

ABSTRACT The specificity of the immune response to the 23-valent pneumococcal-polysaccharide (PS) vaccine in healthy adults and to a pneumococcal conjugate vaccine in infants was examined by measuring immunoglobulin G (IgG) antibody titers by enzyme-linked immunosorbent assay (ELISA) and the opsonophagocytosis assay. ELISA measures total antipneumococcal IgG titers including the titers of functional and nonfunctional antibodies, while the opsonophagocytosis assay measures only functional-antibody titers. Twenty-four pairs of pre- and post-pneumococcal vaccination sera from adults were evaluated (ELISA) for levels of IgG antibodies against serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F. Twelve of the pairs were also examined (opsonophagocytosis assay) for their functional activities. The correlation coefficients between assay results for most types ranged from 0.75 to 0.90, but the correlation coefficient was only about 0.6 for serotypes 4 and 19F. The specificities of these antibodies were further examined by the use of competitive ELISA inhibition. A number of heterologous polysaccharides (types 11A, 12F, 15B, 22F, and 33A) were used as inhibitors. Most of the sera tested showed cross-reacting antibodies, in addition to those removed by pneumococcal C PS absorption. Our data suggest the presence of a common epitope that is found on most pneumococcal PS but that is not absorbed by purified C PS. Use of a heterologous pneumococcal PS (22F) to adsorb the antibodies to the common epitope increased the correlation between the IgG ELISA results and the opsonophagocytosis assay results. The correlation coefficient improve from 0.66 to 0.92 for type 4 and from 0.63 to 0.80 for type 19F. These common-epitope antibodies were largely absent in infants at 7 months of age, suggesting the carbohydrate nature of the epitope.

scholarly journals Protective Immune Responses to the 42-Kilodalton (kDa) Region of Plasmodium yoelii Merozoite Surface Protein 1 Are Induced by the C-Terminal 19-kDa Region but Not by the Adjacent 33-kDa Region

2002 ◽  
Vol 70 (2) ◽  
pp. 820-825 ◽  
Author(s):  
Niklas Ahlborg ◽  
Irene T. Ling ◽  
Wendy Howard ◽  
Anthony A. Holder ◽  
Eleanor M. Riley
Keyword(s):  
Gene Segment ◽  
Surface Protein ◽  
Merozoite Surface Protein ◽  
Plasmodium Yoelii ◽  
Antibody Responses ◽  
Enzyme Linked Immunosorbent Assay ◽  
Igg Antibody ◽  
Merozoite Surface Protein 1 ◽  
Antibody Titers ◽  
Processing Product

ABSTRACT Vaccination of mice with the 42-kDa region of Plasmodium yoelii merozoite surface protein 1 (MSP142) or its 19-kDa C-terminal processing product (MSP119) can elicit protective antibody responses in mice. To investigate if the 33-kDa N-terminal fragment (MSP133) of MSP142 also induces protection, the gene segment encoding MSP133 was expressed as a glutathione S-transferase (GST) fusion protein. C57BL/6 and BALB/c mice were immunized with GST-MSP133 and subsequently challenged with the lethal P. yoelii YM blood stage parasite. GST-MSP133 failed to induce protection, and all mice developed patent parasitemia at a level similar to that in naive or control (GST-immunized) mice; mice immunized with GST-MSP119 were protected, as has been shown previously. Specific prechallenge immunoglobulin G (IgG) antibody responses to MSP1 were analyzed by enzyme-linked immunosorbent assay and immunofluorescence. Despite being unprotected, several mice immunized with MSP133 had antibody titers (of all IgG subclasses) that were comparable to or higher than those in mice that were protected following immunization with MSP119. The finding that P. yoelii MSP133 elicits strong but nonprotective antibody responses may have implications for the design of vaccines for humans based on Plasmodium falciparum or Plasmodium vivax MSP142.

scholarly journals Specific Antibodies in Sera and Gastric Aspirates of Symptomatic and Asymptomatic Helicobacter pylori-Infected Subjects

1998 ◽  
Vol 5 (3) ◽  
pp. 288-293 ◽  
Author(s):  
A. Mattsson ◽  
A. Tinnert ◽  
A. Hamlet ◽  
H. Lönroth ◽  
I. Bölin ◽  
...  
Keyword(s):  
Duodenal Ulcer ◽  
Helicobacter Pylori ◽  
Membrane Proteins ◽  
Immunosorbent Assay ◽  
Antibody Responses ◽  
Enzyme Linked Immunosorbent Assay ◽  
Duodenal Ulcers ◽  
Specific Antibodies ◽  
Antibody Titers ◽  
H Pylori

ABSTRACT In this study we have determined systemic and local antibody responses against different Helicobacter pylori antigens inH. pylori-infected and noninfected subjects. In addition, we studied whether differences in antibody responses between patients with duodenal ulcers and asymptomatic H. pylori carriers might explain the different outcomes of infection. Sera and in most instances gastric aspirates were collected from 19 duodenal ulcer patients, 15 asymptomatic H. pylori carriers, and 20 noninfected subjects and assayed for specific antibodies against different H. pylori antigens, i.e., whole membrane proteins (MP), lipopolysaccharides, flagellin, urease, the neuraminyllactose binding hemagglutinin HpaA, and a 26-kDa protein, by enzyme-linked immunosorbent assay. The H. pylori-infected subjects had significantly higher antibody titers against MP, flagellin, and urease in both sera and gastric aspirates compared with the noninfected subjects. Furthermore, the antibody titers against HpaA were significantly elevated in sera but not in gastric aspirates from the infected subjects. However, no differences in antibody titers against any of the tested antigens could be detected between the duodenal ulcer patients and the asymptomatic H. pyloricarriers, either in sera or in gastric aspirates.

scholarly journals Enzyme-Linked Immunosorbent Assay for Measurement of Cytomegalovirus Glycoprotein B Antibody in Serum

2010 ◽  
Vol 17 (5) ◽  
pp. 836-839 ◽  
Author(s):  
Daniel J. Hackett ◽  
Changpin Zhang ◽  
Carla Stefanescu ◽  
Robert F. Pass
Keyword(s):  
Immunosorbent Assay ◽  
Geometric Mean ◽  
Mean Value ◽  
Glycoprotein B ◽  
Enzyme Linked Immunosorbent Assay ◽  
Igg Antibody ◽  
Negative Results ◽  
Wide Range ◽  
The Mean ◽  
Antibody Levels

ABSTRACT Measurement of antibody to cytomegalovirus (CMV) glycoprotein B (gB) is valuable in the assessment of the antibody response to infection and to gB-containing vaccines. For this purpose, an enzyme-linked immunosorbent assay (ELISA) with a recombinant CMV gB molecule as the antigen was evaluated. Sera from 168 anti-CMV IgG-positive and 100 seronegative subjects were used to evaluate the anti-gB antibody assay. A cutoff optical density (OD) that would distinguish gB antibody-positive from -negative sera was established. Titers of antibody to gB determined by endpoint dilution were compared with those calculated using regression analysis. The run-to-run and interoperator reproducibilities of results were measured. The mean OD + 5 standard deviations from 50 anti-CMV IgG antibody-negative sera (0.2472) was used as the cutoff between anti-gB antibody-positive and -negative results. All sera from 100 anti-CMV IgG-seronegative subjects were negative for antibody to gB. All but 1 of 168 sera from seropositive subjects were positive for antibody to gB. Observed antibody levels based on titration to the endpoint were very similar to results calculated using linear regression. The run-to-run consistency of endpoints was excellent, with 38 runs from one operator and 48 runs from another all giving results within 1 dilution of the mean value for each of three anti-CMV IgG antibody-positive serum pools. The geometric mean titer of antibody to gB for 99 sera from seropositive blood donors was 1/10,937. This ELISA gives accurate and reproducible results for the relative quantity of anti-CMV gB IgG in serum over a wide range of antibody levels.

scholarly journals Serological assessment of SARS-CoV-2 infection during the first wave of the pandemic in Louisville Kentucky

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Krystal T. Hamorsky ◽  
Adrienne M. Bushau-Sprinkle ◽  
Kathleen Kitterman ◽  
Julia M. Corman ◽  
Jennifer DeMarco ◽  
...  
Keyword(s):  
Immune Response ◽  
Sensitivity And Specificity ◽  
Immunosorbent Assay ◽  
Receptor Binding ◽  
Healthcare Workers ◽  
Antibody Responses ◽  
Enzyme Linked Immunosorbent Assay ◽  
Receptor Binding Domain ◽  
Iga Antibodies ◽  
Antibody Titers

AbstractSerological assays intended for diagnosis, sero-epidemiologic assessment, and measurement of protective antibody titers upon infection or vaccination are essential for managing the SARS-CoV-2 pandemic. Serological assays measuring the antibody responses against SARS-CoV-2 antigens are readily available. However, some lack appropriate characteristics to accurately measure SARS-CoV-2 antibodies titers and neutralization. We developed an Enzyme-linked Immunosorbent Assay (ELISA) methods for measuring IgG, IgA, and IgM responses to SARS-CoV-2, Spike (S), receptor binding domain (RBD), and nucleocapsid (N) proteins. Performance characteristics of sensitivity and specificity have been defined. ELISA results show positive correlation with microneutralization and Plaque Reduction Neutralization assays with infectious SARS-CoV-2. Our ELISA was used to screen healthcare workers in Louisville, KY during the first wave of the local pandemic in the months of May and July 2020. We found a seropositive rate of approximately 1.4% and 2.3%, respectively. Our analyses demonstrate a broad immune response among individuals and suggest some non-RBD specific S IgG and IgA antibodies neutralize SARS-CoV-2.

scholarly journals Emergency response for evaluating SARS-CoV-2 immune status, seroprevalence and convalescent plasma in Argentina

2021 ◽  
Vol 17 (1) ◽  
pp. e1009161 ◽  
Author(s):  
Diego S. Ojeda ◽  
María Mora Gonzalez Lopez Ledesma ◽  
Horacio M. Pallarés ◽  
Guadalupe S. Costa Navarro ◽  
Lautaro Sanchez ◽  
...  
Keyword(s):  
Longitudinal Studies ◽  
Neutralizing Antibody ◽  
Antibody Responses ◽  
Enzyme Linked Immunosorbent Assay ◽  
Igg Antibody ◽  
Health Authorities ◽  
New Information ◽  
Wide Range ◽  
Private And Public ◽  
Antibody Titers

We report the emergency development and application of a robust serologic test to evaluate acute and convalescent antibody responses to SARS-CoV-2 in Argentina. The assays, COVIDAR IgG and IgM, which were produced and provided for free to health authorities, private and public health institutions and nursing homes, use a combination of a trimer stabilized spike protein and the receptor binding domain (RBD) in a single enzyme-linked immunosorbent assay (ELISA) plate. Over half million tests have already been distributed to detect and quantify antibodies for multiple purposes, including assessment of immune responses in hospitalized patients and large seroprevalence studies in neighborhoods, slums and health care workers, which resulted in a powerful tool for asymptomatic detection and policy making in the country. Analysis of antibody levels and longitudinal studies of symptomatic and asymptomatic SARS-CoV-2 infections in over one thousand patient samples provided insightful information about IgM and IgG seroconversion time and kinetics, and IgM waning profiles. At least 35% of patients showed seroconversion within 7 days, and 95% within 45 days of symptoms onset, with simultaneous or close sequential IgM and IgG detection. Longitudinal studies of asymptomatic cases showed a wide range of antibody responses with median levels below those observed in symptomatic patients. Regarding convalescent plasma applications, a protocol was standardized for the assessment of end point IgG antibody titers with COVIDAR with more than 500 plasma donors. The protocol showed a positive correlation with neutralizing antibody titers, and was used for clinical trials and therapies across the country. Using this protocol, about 80% of convalescent donor plasmas were potentially suitable for therapies. Here, we demonstrate the importance of providing a robust and specific serologic assay for generating new information about antibody kinetics in infected individuals and mitigation policies to cope with pandemic needs.

scholarly journals Development of an Enzyme-Linked Immunosorbent Assay To Detect Antibodies Targeting Recombinant Envelope Protein 2 of Mayaro Virus

2019 ◽  
Vol 57 (5) ◽  
Author(s):  
Marcílio Jorge Fumagalli ◽  
William Marciel de Souza ◽  
Marília Farignoli Romeiro ◽  
Michell Charles de Souza Costa ◽  
Renata Dezengrini Slhessarenko ◽  
...  
Keyword(s):  
Immunosorbent Assay ◽  
Envelope Protein ◽  
Cross Reactivity ◽  
Antibody Detection ◽  
Enzyme Linked Immunosorbent Assay ◽  
High Avidity ◽  
Serum Samples ◽  
Igg Antibody ◽  
Mayaro Virus ◽  
Recombinant Envelope Protein

ABSTRACT Mayaro virus (MAYV) is a neglected arthropod-borne virus (arbovirus) antigenically clustered into the Semliki Forest complex group of Alphavirus genus (Togaviridae family), maintained in an unclear zoonotic cycle involving mosquitoes from Haemagogus genus as the main vector. The genome is composed of a positive single-stranded RNA of 11.5 kb in length, which contains two genes that encode four nonstructural (nsP1 to nsP4) and five structural (C, E3, E2, 6K, and E1) proteins. In the present study, we have developed an enzyme-linked immunosorbent assay (ELISA) using as antigen the recombinant envelope protein 2 of MAYV produced in an Escherichia coli system (rE2-MAYV ELISAs). A panel of 68 human serum samples from suspected arboviral cases was analyzed and titrated for anti-MAYV IgM and IgG antibody detection. The rE2-MAYV ELISA detected 33.8% (23/68) IgG-positive samples, demonstrating 100% sensitivity and 78.95% specificity compared to the MAYV-specific 50% plaque reduction neutralization assay. In addition, the positive MAYV-neutralizing samples showed high titers of detection by rE2-MAYV ELISA, suggesting a highly sensitive test. The rE2-MAYV ELISA also detected 42.5% (29/68) IgM-positive samples, of which 13.8% (4/29) presented high-avidity interactions with rE2-MAYV. Cross-reactivity was observed with Chikungunya virus (CHIKV)-specific murine antibody sample but not with CHIKV-specific human and other Alphavirus murine antibodies. In short, we have developed a rapid, simple, specific, and sensitive MAYV rE2-ELISA, and our preliminary results show its potential applicability to diagnosis of MAYV infections.

scholarly journals Cross-Sectional Study of Varicella Zoster Virus Immunity in Healthy Korean Children Assessed by Glycoprotein Enzyme-Linked Immunosorbent Assay and Fluorescent Antibody to Membrane Antigen Test

Vaccines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 492
Author(s):  
Yunhwa Kim ◽  
Ji-Young Hwang ◽  
Kyung-Min Lee ◽  
Eunsil Lee ◽  
Hosun Park
Keyword(s):  
South Korea ◽  
Immunosorbent Assay ◽  
Fluorescent Antibody ◽  
Seroconversion Rate ◽  
Geometric Mean ◽  
Varicella Vaccine ◽  
Enzyme Linked Immunosorbent Assay ◽  
Healthy Children ◽  
Korean Children ◽  
Post Vaccination

The prevalence of varicella is especially high among children in the age group of 4–6 years in South Korea, regardless of vaccination. We investigated the immune status of healthy children enrolled in day-care centers and compared pre- and post-vaccination immunity. Antibody titers were measured using a glycoprotein enzyme-linked immunosorbent assay (gpEIA) kit, and the seroconversion rate was assessed using a fluorescent antibody to membrane antigen (FAMA) test. Among 541 vaccinated children, 109 (20.1%) had breakthrough varicella. However, 13 (72.2%) of the 18 unvaccinated children had a history of varicella. The gpEIA geometric mean titers (GMTs) of pre- and 5 weeks post-vaccination in 1-year-old children were 14.7 and 72 mIU/mL, respectively, and the FAMA seroconversion rate was 91.1%. The gpEIA GMTs of 2-, 3-, 4-, 5-, and 6-year-old children were 104.1, 133.8, 223.5, 364.1, and 353.0 mIU/mL, respectively. Even though the gpEIA GMT increased with age, the pattern of gpEIA titer distribution in 4- to 6-year-old vaccinees without varicella history represented both waning immunity and natural boosting immunity. These results suggest that some vaccinees are vulnerable to varicella infection. Therefore, it is necessary to consider a two-dose varicella vaccine regimen in South Korea.

Comparison of an enzyme-linked immunosorbent assay for quantitation of rotavirus antibodies with complement fixation in an epidemiological survey

1978 ◽  
Vol 8 (3) ◽  
pp. 268-276
Author(s):  
L H Ghose ◽  
R D Schnagl ◽  
I H Holmes
Keyword(s):  
Immunosorbent Assay ◽  
Complement Fixation ◽  
Age Groups ◽  
Enzyme Reaction ◽  
Epidemiological Survey ◽  
Enzyme Linked Immunosorbent Assay ◽  
Marker Enzyme ◽  
Aminosalicylic Acid ◽  
Antibody Titers ◽  
Antibody Levels

The development of a micro-scale enzyme-linked immunosorbent assay (ELISA) with horseradish peroxidase as the marker enzyme for the detection and measurement of human rotavirus antibodies is described. A semipurified preparation of the serologically related simian agent, SA-11 virus, was used as the antigen. Test sera were reacted with antigen-sensitized wells in disposable poly-vinyl microplates. Any attached antibody was detected by the addition of peroxidase-labeled anti-species immunoglobulin (conjugate) followed by assay of the enzyme reaction with its substrate, hydrogen peroxide plus 5-aminosalicylic acid. This micro-ELISA was compared with complement fixation in a seroepidemiological study of the age prevalence of rotavirus antibody in Aboriginal and European populations living in the same outback area in Australia. The ELISA (results read with the naked eye) proved to be approximately 16 times more sensitive than complement fixation. Of Aborigines, 71% had rotavirus complement-fixing antibody, as compared to 45% of Europeans. By ELISA 100% of both populations had rotavirus antibodies. Mean antibody titers in the different age groups were higher in Aborigines than in Europeans. Antibody levels rose steeply throughout the first 20 years of life, remained high during the next 20 years, then increased again at least up to the age of 60 years. The micro-ELISA was practical, simple to perform, and more suitable than complement fixation for large seroepidemiological rotavirus studies. It also has potential for serodiagnosis of the disease, both in the laboratory and in the field.

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