scholarly journals Naturally Acquired Antibodies against Four Enterococcus faecalis Capsular Polysaccharides in Healthy Human Sera

2005 ◽  
Vol 12 (8) ◽  
pp. 930-934 ◽  
Author(s):  
Markus Hufnagel ◽  
Andrea Kropec ◽  
Christian Theilacker ◽  
Johannes Huebner
Keyword(s):  
Capsular Polysaccharide ◽  
Low Frequency ◽  
Cross Reactivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Capsular Polysaccharides ◽  
Healthy Human ◽  
Healthy Donors ◽  
Human Sera ◽  
Antibody Titers ◽  
Opsonophagocytic Killing

ABSTRACT Healthy human sera (HHS) contain naturally acquired enterococcal antibodies which promote neutrophil-mediated killing. The target antigens remain unknown. The present study used a capsular polysaccharide (CPS)-enzyme-linked immunosorbent assay (ELISA) to investigate whether the HHS antibodies of 12 healthy donors bound to the CPS of four E. faecalis serotypes (CPS-A to CPS-D) and then employed an opsonic-killing assay to determine if these antibodies mediated phagocyte-dependent killing. All HHS contained immunoglobulin G (IgG) and IgM antibodies directed against capsular polysaccharides of the four serotypes. Absorption of the sera with homologous and heterologous strains showed a majority of antibodies to be cross-reactive among the prototype strains. The susceptibility of the four prototype strains to opsonic killing varied. Opsonic killing of CPS-A and CPS-B strains was significantly higher than killing of CPS-C and CPS-D strains. Absorption studies revealed that the opsonic killing of HHS was only partially type specific, with cross-reactivity between CPS-A and CPS-B strains and between CPS-C and CPS-D strains. These data indicate that healthy individuals possess opsonic antibodies specific for CPS-A and CPS-B but only low titers of opsonic antibodies against CPS-C and CPS-D. Titers of opsonic antibodies did not correlate with antibody titers measured by ELISA. Whether this lack of correlation is due to the low frequency of opsonic antibodies or to increased resistance to the opsonophagocytic killing of some serotypes remains to be determined.

scholarly journals Development and Evaluation of a Tetraplex Flow Cytometric Assay for Quantitation of Serum Antibodies to Neisseria meningitidis Serogroups A, C, Y, and W-135

2004 ◽  
Vol 11 (2) ◽  
pp. 272-279 ◽  
Author(s):  
Gouri Lal ◽  
Paul Balmer ◽  
Helen Joseph ◽  
Maureen Dawson ◽  
Ray Borrow
Keyword(s):  
Neisseria Meningitidis ◽  
Capsular Polysaccharide ◽  
Cross Reactivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Capsular Polysaccharides ◽  
Simple Method ◽  
Serum Dilution ◽  
Flow Cytometric ◽  
Important Addition ◽  
Inhibition Studies

ABSTRACT A rapid and simple method for the simultaneous quantitation of serum immunoglobulin G (IgG) antibodies specific for Neisseria meningitidis serogroups A, C, Y, and W-135 was developed and evaluated. Four bead sets were generated, each conjugated with one of the meningococcal capsular polysaccharides (A, C, Y, or W-135) and serologically assessed by the use of antimeningococcal international reference sera. Cross-reactivity studies demonstrated no inhibition between monoplex and multiplex assays, and the assay was linear over a 24-fold serum dilution range. Inhibition studies demonstrated that the assay is specific, with <25% heterologous inhibition occurring. The assay was also found to have low intra- and interassay variations and limits of detection ≤650 pg/ml. A comparison of the meningococcal bead assay with the standardized meningococcal enzyme-linked immunosorbent assay showed a good correlation between the IgG concentrations obtained by each assay. The tetraplex assay has the potential to be an important addition to the serologic evaluation of meningococcal capsular polysaccharide conjugate vaccines.

scholarly journals Effect of Antigen Coating Conditions on Enzyme-Linked Immunosorbent Assay for Detection of Immunoglobulin G Antibody to Neisseria meningitidis Serogroup Y and W135 Capsular Polysaccharide Antigens in Serum

2003 ◽  
Vol 10 (6) ◽  
pp. 1136-1140 ◽  
Author(s):  
Peter C. Giardina ◽  
Renee E. Evans ◽  
Daniel J. Sikkema ◽  
Dace Madore ◽  
Stephen W. Hildreth
Keyword(s):  
Immunoglobulin G ◽  
Capsular Polysaccharide ◽  
Enzyme Linked Immunosorbent Assay ◽  
Meningococcal Vaccine ◽  
Igg Antibody ◽  
Human Sera ◽  
Polysaccharide Antigens ◽  
Reference Serum ◽  
Adult Volunteers ◽  
Assay Conditions

ABSTRACT Human sera collected from 28 consenting adult volunteers were used to define assay conditions for meningococcal vaccine clinical trial serology. Immunoassay parameters were optimized with these test sera and the standard reference serum, CDC1992. Coating conditions for serogroup Y and W135 polysaccharide antigens were found to influence the predicted serum immunoglobulin G (IgG) antibody concentrations. Sera that displayed IgG antibody binding profiles most unlike that of CDC1992 were influenced the most by coating conditions. Our results suggest that presentation of specific epitopes is influenced by antigen-coating concentrations for serogroup Y and W135 polysaccharides.

scholarly journals Analysis of Human Serum Immunoglobulin G against O-Acetyl-Positive and O-Acetyl-Negative Serogroup W135 Meningococcal Capsular Polysaccharide

2005 ◽  
Vol 12 (5) ◽  
pp. 586-592 ◽  
Author(s):  
Peter C. Giardina ◽  
Emma Longworth ◽  
Renee E. Evans-Johnson ◽  
Michaelene L. Bessette ◽  
Hong Zhang ◽  
...  
Keyword(s):  
Immunoglobulin G ◽  
Capsular Polysaccharide ◽  
Solid Phase ◽  
Geometric Mean ◽  
Serum Antibody ◽  
Fluid Phase ◽  
Enzyme Linked Immunosorbent Assay ◽  
Antibody Titers ◽  
The Impact

ABSTRACT The capsular polysaccharide of Neisseria meningitidis serogroup W135 is expressed in both O-acetyl-positive (OA+) and O-acetyl-negative (OA−) forms. This study investigates the impact of OA status (OA+ versus OA−) on serological measurements of anti-W135 immunoglobulin G (IgG) antibodies in immunized adults. W135-specific serum antibody assignments were made for 28 postimmunization sera from adults by enzyme-linked immunosorbent assay using the meningococcal standard reference serum CDC1992. The established IgG concentration in micrograms per milliliter ([IgG]μg/ml) for CDC1992 against OA+ antigen (16.2 μg/ml) was used as a reference to assign a concentration of 10.13 μg/ml IgG against OA− antigen by cross-standardization. Overall, the IgG assignments for these sera were higher against OA+ antigen (geometric mean concentration [GMC] = 7.16 μg/ml) than against OA− antigen (GMC = 2.84 μg/ml). However, seven sera showed higher specific [IgG]μg/ml values against the OA+ antigen than against the OA− antigen. These sera were also distinguished by the inability of fluid-phase OA− antigen to compete for antibody binding to OA+ solid-phase antigen. Although there was no overall difference in functional activity measured by complement-mediated serum bactericidal assay (SBA) against OA+ and OA− target bacteria (geometric mean titers of 9,642 and 9,045, respectively), three serum specimens showed a large difference in SBA antibody titers against OA+ versus OA− W135 target bacteria, which may reflect different epitope specificities for these sera. Our data indicate that, for some sera, the agreement in anti-OA+ versus anti-OA− W135 IgG assignments is serum specific and does not reflect the functional (killing) activity in vitro.

scholarly journals Anti-SARS-CoV-2 Antibodies Within IVIg Preparations: Cross-Reactivities With Seasonal Coronaviruses, Natural Autoimmunity, and Therapeutic Implications

2021 ◽  
Vol 12 ◽  
Author(s):  
Marinos C. Dalakas ◽  
Kleopatra Bitzogli ◽  
Harry Alexopoulos
Keyword(s):  
Ivig Therapy ◽  
Treated Group ◽  
Cross Reactivity ◽  
Controlled Study ◽  
Enzyme Linked Immunosorbent Assay ◽  
High Dose ◽  
Antigenic Peptides ◽  
Protein Fragments ◽  
Therapeutic Implications ◽  
Healthy Donors

Introduction: Cross-reactivity to SARS-CoV-2 antigenic peptides has been detected on T-cells from pre-pandemic donors due to recognition of conserved protein fragments within members of the coronavirus's family. Further, preexisting antibodies recognizing SARS-CoV-2 with conserved epitopes in the spike region have been now seen in uninfected individuals. High-dose Intravenous Immunoglobulin (IVIg), derived from thousands of healthy donors, contains natural IgG antibodies against various antigens which can be detected both within the IVIg preparations and in the serum of IVIg-receiving patients. Whether IVIg preparations from pre-pandemic donors also contain antibodies against pre-pandemic coronaviruses or autoreactive antibodies that cross-react with SARS-CoV-2 antigenic epitopes, is unknown.Methods: 13 samples from 5 commercial IVIg preparations from pre-pandemic donors (HyQvia (Baxalta Innovations GmbH); Privigen (CSL Behring); Intratect (Biotest AG); IgVena (Kedrion S.p.A); and Flebogamma (Grifols S.A.) were blindly screened using a semi-quantitative FDA-approved and validated enzyme-linked immunosorbent assay (ELISA) (Euroimmun, Lubeck, Germany).Results: Nine of thirteen preparations (69.2%), all from two different manufactures, were antibody-positive based on the defined cut-off positivity (index of sample OD to calibrator OD &gt; 1.1). From one manufacturer, 7/7 lots (100%) and from another 2/3 lots (67%), tested positive for cross-reacting antibodies. 7/9 of the positive preparations (77%) had titers as seen in asymptomatically infected individuals or recent COVID19-recovered patients, while 2/9 (23%) had higher titers, comparable to those seen in patients with active symptomatic COVID-19 infection (index &gt; 2.2).Conclusion: Pre-pandemic IVIg donors have either natural autoantibodies or pre-pandemic cross-reactive antibodies against antigenic protein fragments conserved among the “common cold” - related coronaviruses. The findings are important in: (a) assessing true anti-SARS-CoV-2-IgG seroprevalence avoiding false positivity in IVIg-receiving patients; (b) exploring potential protective benefits in patients with immune-mediated conditions and immunodeficiencies receiving acute or chronic maintenance IVIg therapy, and (c) validating data from a recent controlled study that showed significantly lower in-hospital mortality in the IVIg- treated group.

Production and Characterization of Antibodies Against Neosaxitoxin

1992 ◽  
Vol 75 (2) ◽  
pp. 341-345 ◽  
Author(s):  
Fun S Chu ◽  
Xuan Huang ◽  
Sherwood Hall
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Bovine Serum ◽  
Indirect Elisa ◽  
Cross Reactivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
High Antibody ◽  
Antibody Titers ◽  
Antibody Elisa

Abstract Antibody against neosaxitoxin (neo-STX) was obtained from rabbits after immunization with neo- STX conjugated to either keyhole limpet hemocyanln (KLH) or bovine serum albumin (BSA). An indirect enzyme-linked Immunosorbent assay (ELISA), In which either neo-STX-BSA or neo-STXKLH was coated to the mlcroplate, was used to monitor the antibody titer. Although high antibody titers were obtained from rabbits after immunization with both immunogens, only antibody obtained from rabbits immunized with neo-STX-KLH was useful for Immunoassay. Competitive indirect ELISA revealed that the antibodies obtained from rabbits Immunized with neo-STX-KLH are specific for neo-STX but also have good cross-reactivity with STX. The concentrations causing 50% inhibition binding of neo-STX-BSA to the anti-neo-KLH by neo-STX, STX, and decarbamoyl-STX (DC-STX) were 0.9,8.0, and 53.1 ng/mL, respectively. Saxitoxin conjugated to polylyslne (STX-PLL) was also used as the coating reagent In the indirect ELISA. The concentrations causing 50% inhibition binding of antl-neo-STX-KLH to STX-PLL coated on the mlcrotiter plate by neo-STX, STX, and DC-STX were 1.2,4.1, and 36.1 ng/mL, respectively. With this newly developed antibody, ELISA could be a very effective method for monitoring seafood for both neo-STX and STX.

scholarly journals Effect of O Acetylation of Neisseria meningitidis Serogroup A Capsular Polysaccharide on Development of Functional Immune Responses

2002 ◽  
Vol 70 (7) ◽  
pp. 3707-3713 ◽  
Author(s):  
David S. Berry ◽  
Freyja Lynn ◽  
Che-Hung Lee ◽  
Carl E. Frasch ◽  
Margaret C. Bash
Keyword(s):  
Immune Responses ◽  
Neisseria Meningitidis ◽  
Conjugate Vaccine ◽  
Essential Role ◽  
Capsular Polysaccharide ◽  
Enzyme Linked Immunosorbent Assay ◽  
Dramatic Reduction ◽  
Mouse Immunization ◽  
Human Sera ◽  
Inhibition Studies

ABSTRACT The importance of O-acetyl groups to the immunogenicity of Neisseria meningitidis serogroup A polysaccharide (PS) was examined in studies using human sera and mouse immunization. In 17 of 18 postimmunization human sera, inhibition enzyme-linked immunosorbent assay indicated that the majority of antibodies binding to serogroup A PS were specific for epitopes involving O-acetyl groups. Studies with mice also showed an essential role for O-acetyl groups, where serum bactericidal titers following immunization with de-O-acetylated (de-O-Ac) conjugate vaccine were at least 32-fold lower than those following immunization with O-Ac PS-conjugate vaccine and 4-fold lower than those following immunization with native capsular PS. Inhibition studies using native and de-O-Ac PS confirmed the specificity of murine antibodies to native PS. The dramatic reduction in immunogenicity associated with removal of O-acetyl groups indicates that O acetylation is essential to the immunogenic epitopes of serogroup A PS. Since levels of bactericidal antibodies are correlated with protection against disease, O-acetyl groups appear to be important in protection.

scholarly journals Leishmania major-Like Antigen for Specific and Sensitive Serodiagnosis of Human and Canine Visceral Leishmaniasis

2002 ◽  
Vol 9 (6) ◽  
pp. 1361-1366 ◽  
Author(s):  
Rosângela Barbosa-de-Deus ◽  
Marcos Luíz dos Mares-Guia ◽  
Adriane Zacarias Nunes ◽  
Kátia Morais Costa ◽  
Roberto Gonçalves Junqueira ◽  
...  
Keyword(s):  
Visceral Leishmaniasis ◽  
Rheumatoid Factor ◽  
Chagas Disease ◽  
Leishmania Major ◽  
Antibody Test ◽  
Cross Reactivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Parasitological Diagnosis ◽  
Human Sera ◽  
Indirect Immunofluorescent

ABSTRACT An antigen (LMS) prepared from Leishmania major-like promastigotes was used in an enzyme-linked immunosorbent assay (ELISA) for the diagnosis of human and dog visceral leishmaniasis. The results were compared with those from the indirect immunofluorescent antibody test (IFAT). A total of 1,822 canine sera were tested, including sera from dogs with visceral leishmaniasis, transmissible venereal tumors, ehrlichiosis, rickettsiosis, or Chagas' disease and sera from healthy dogs. The antigen was also tested with 227 samples of human sera, including sera from patients with visceral, cutaneous, or diffuse cutaneous leishmaniasis and from noninfected individuals, as well as sera from patients with Chagas' disease, toxoplasmosis, rickettsiosis, hepatitis B, schistosomiasis, ascaridiasis, malaria, rheumatoid factor, leprosy and rheumatoid factor, tuberculosis, or leprosy. All dogs and all human patients had a clinical and/or serological and/or parasitological diagnosis. For detecting antibodies in sera from dogs with leishmaniasis, the antigen showed a sensitivity of 98%, specificity of 95%, and concordance of 93% and when used for detecting antibodies in human sera presented a sensitivity of 92%, specificity of 100%, and concordance of 92%. Comparison between ELISA and IFAT demonstrated that ELISA using the LMS antigen yielded more reliable results than IFAT. The LMS antigen displayed no cross-reactivity with sera from patients or dogs that had any of the other diseases tested.

scholarly journals Assignment of Immunoglobulin G1 and G2 Concentrations to Pneumococcal Capsular Polysaccharides 3, 6B, 14, 19F, and 23F in Pneumococcal Reference Serum 89-SF

1998 ◽  
Vol 5 (4) ◽  
pp. 561-566 ◽  
Author(s):  
Anu Soininen ◽  
Ilkka Seppälä ◽  
Tomi Wuorimaa ◽  
Helena Käyhty
Keyword(s):  
Immunosorbent Assay ◽  
Capsular Polysaccharide ◽  
Enzyme Linked Immunosorbent Assay ◽  
Capsular Polysaccharides ◽  
Serum Pool ◽  
Reference Serum

ABSTRACT We describe standardization of an enzyme-linked immunosorbent assay (ELISA) for measuring immunoglobulin G1 (IgG1) and IgG2 concentrations of antibodies to pneumococcal capsular polysaccharide (Pnc PS). The ELISA uses a human pneumococcal reference serum pool, lot 89-SF, as a reference. IgG1 and IgG2 concentrations were assigned to antibodies to Pnc PS serotypes 3, 6B, 14, 19F, and 23F in 89-SF by ELISA using affinity-purified monoisotypic IgG1 and IgG2 preparations. The sum of IgG1 and IgG2 concentrations in 89-SF agrees well with the previously assigned IgG concentrations. The IgG1 and IgG2 values in 89-SF were used to measure antibodies to Pnc PS 6B, 14, and 23F in adult pre- and postimmunization sera and the sum of IgG1 and IgG2 concentrations correlated well with the IgG values. Furthermore, the IgG2/IgG1 ratio did not affect the detection of IgG1, the isotype usually represented by a lower concentration.

scholarly journals Chemical Structure, Conjugation, and Cross-Reactivity of Bacillus pumilus Sh18 Cell Wall Polysaccharide

2004 ◽  
Vol 186 (20) ◽  
pp. 6891-6901 ◽  
Author(s):  
Joanna Kubler-Kielb ◽  
Bruce Coxon ◽  
Rachel Schneerson
Keyword(s):  
Cell Wall ◽  
Chemical Structure ◽  
Capsular Polysaccharide ◽  
Bacillus Pumilus ◽  
Minor Component ◽  
Cross Reactivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Hydroxyl Groups ◽  
Cell Wall Polysaccharide ◽  
Glycerol Phosphate

ABSTRACT Bacillus pumilus strain Sh18 cell wall polysaccharide (CWP), cross-reactive with the capsular polysaccharide of Haemophilus influenzae type b, was purified and its chemical structure was elucidated using fast atom bombardment mass spectrometry, nuclear magnetic resonance techniques, and sugar-specific degradation procedures. Two major structures, 1,5-poly(ribitol phosphate) and 1,3-poly(glycerol phosphate), with the latter partially substituted by 2-acetamido-2-deoxy-α-galactopyranose (13%) and 2-acetamido-2-deoxy-α-glucopyranose (6%) on position O-2, were found. A minor component was established to be a polymer of →3-O-(2-acetamido-2-deoxy-β-glucopyranosyl)-1→4-ribitol-1-OPO3→. The ratios of the three components were 56, 34, and 10 mol%, respectively. The Sh18 CWP was covalently bound to carrier proteins, and the immunogenicity of the resulting conjugates was evaluated in mice. Two methods of conjugation were compared: (i) binding of 1-cyano-4-dimethylaminopyridinium tetrafluoroborate-activated hydroxyl groups of the CWP to adipic acid dihydrazide (ADH)-derivatized protein, and (ii) binding of the carbodiimide-activated terminal phosphate group of the CWP to ADH-derivatized protein. The conjugate-induced antibodies reacted in an enzyme-linked immunosorbent assay with the homologous polysaccharide and with a number of other bacterial polysaccharides containing ribitol and glycerol phosphates, including H. influenzae types a and b and strains of Staphylococcus aureus and Staphylococcus epidermidis.

scholarly journals Evaluation of the Specificity of Pneumococcal Polysaccharide Enzyme-Linked Immunosorbent Assay and the Effect of Serum Adsorption Based on Standard Pneumococcal Serogroup- or Serotype-Specific Rabbit Antisera

2009 ◽  
Vol 16 (9) ◽  
pp. 1279-1284 ◽  
Author(s):  
Hans-Christian Slotved ◽  
Christina Guttmann ◽  
Charlotte Demuth Pedersen ◽  
Jasper Neergaard Jacobsen ◽  
Karen Angeliki Krogfelt
Keyword(s):  
Cell Wall ◽  
Streptococcus Pneumoniae ◽  
Human Serum ◽  
Immunosorbent Assay ◽  
Capsular Polysaccharide ◽  
Enzyme Linked Immunosorbent Assay ◽  
Capsular Polysaccharides ◽  
Who Guidelines ◽  
Specific Antibodies ◽  
Specific Rabbit

ABSTRACT Worldwide, Streptococcus pneumoniae (pneumococcus) is a major cause of morbidity and mortality, especially in infants and elderly people. Pneumococcal capsular polysaccharides are well characterized, and more than 90 different serotypes have been identified. Serotype-specific antibodies against the capsular polysaccharide are produced during infection. Detection of antibodies against pneumococci by enzyme-linked immunosorbent assay (ELISA) is performed according to WHO guidelines, using antigens provided by ATCC. However, testing the ELISA for specificity is challenging due to the difficulty in obtaining human naïve serum with pneumococcal antibodies as well as human serum with antibodies against a single serotype. The application of well-defined serotype-specific sera produced in animals to evaluate the specificity of the ATCC antigens and the effect of adsorption with cell wall and 22F polysaccharides has not been performed before, to our knowledge. In this study, the specificity of ATCC antigens (serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F) was tested by using commercial serotype-, serogroup-, and pool-specific pneumococcal rabbit antisera.

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