scholarly journals Evaluation of Serum Bactericidal Antibody Assays forHaemophilus influenzaeSerotype a

2010 ◽  
Vol 18 (2) ◽  
pp. 243-247 ◽  
Author(s):  
Nadine G. Rouphael ◽  
Sarah Satola ◽  
Monica M. Farley ◽  
Karen Rudolph ◽  
Daniel S. Schmidt ◽  
...  
Keyword(s):  
Haemophilus Influenzae ◽  
American Indian ◽  
Immunosorbent Assay ◽  
Bactericidal Activity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Alaskan Native ◽  
Serum Bactericidal Activity ◽  
Aboriginal Populations ◽  
Antibody Assays ◽  
Bactericidal Antibody

ABSTRACTHaemophilus influenzaetype a (Hia) is an important pathogen for some American Indian, Alaskan native, and Northern Canada aboriginal populations. Assays to measure serum bactericidal activity (SBA) to Hia have not been developed or validated. Here, we describe two methods for the measurement of SBA: SBA with a viability endpoint (CFU counts) and SBA with a fluorometric endpoint using alamarBlue as the metabolic indicator. Both SBA assays measure Hia-specific functional antibody and correlate with anti-Hia IgG enzyme-linked immunosorbent assay (ELISA) concentration of naturally acquired antibodies.

scholarly journals Humoral Immune Responses to Neisseria meningitidis in Children

1999 ◽  
Vol 67 (5) ◽  
pp. 2441-2451 ◽  
Author(s):  
Andrew J. Pollard ◽  
Rachel Galassini ◽  
Eileene M. Rouppe van der Voort ◽  
Robert Booy ◽  
Paul Langford ◽  
...  
Keyword(s):  
Immune Responses ◽  
Neisseria Meningitidis ◽  
Bactericidal Activity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Older Children ◽  
Recent Infection ◽  
Humoral Immune ◽  
Serum Bactericidal Activity ◽  
Humoral Immune Responses ◽  
Bactericidal Antibody

ABSTRACT An understanding of the nature of immunity to serogroup B meningococci in childhood is necessary in order to establish the reasons for poor responses to candidate vaccines in infancy. We sought to examine the nature of humoral immune responses following infection in relation to age. Serum bactericidal activity was poor in children under 12 months of age despite recent infection with Neisseria meningitidis. The highest levels of bactericidal activity were seen in children over 10 years of age. However, infants produced levels of total immunoglobulin G (IgG) and IgG subclass antibodies similar to those in older children in a meningococcal enzyme-linked immunosorbent assay. Most antibody was of the IgG1 and IgG3 subclasses. This striking age dependency of bactericidal antibody response following infection is not apparently due to failure of class switching in infants but might be due to qualitative differences in antibody specificity or affinity.

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.

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