Comparison of a New Multiplex Binding Assay versus the Enzyme-Linked Immunosorbent Assay for Measurement of Serotype-Specific Pneumococcal Capsular Polysaccharide IgG

Abstract

The measurement of serotype-specific anti-capsular polysaccharide antibodies remains the mainstay of pneumococcal (Pn) vaccine evaluation. New methods that allow the simultaneous measurement of antibodies to several antigens in small volumes of serum, and that agree well with existing techniques, are urgently required to support the increasing number of concomitant vaccines delivered in the infant immunization schedules and the use of extended-valency Pn vaccines. We therefore compared a relatively new multiplexed platform for measuring anti-Pn antibodies with the existing WHO consensus enzyme-linked immunosorbent assay (ELISA). A panel of 50 pediatric samples (34 collected after receipt of a heptavalent pneumococcal conjugate vaccine [PCV7] and 16 without PCV7) was analyzed across two different laboratories using a new multiplex electrochemiluminescence (ECL)-based detection assay developed for the quantitation of IgG serotype-specific antipneumococcal antibodies, and the results were compared to those obtained using the WHO consensus ELISA. For the seven serotypes measured, there was good agreement between the techniques and laboratories. The most notable difference was found between the ECL assay and the ELISA: concentrations tended to be higher in the ECL assay. For serotypes 6B, 9V, 18C, and 23F, the average increases in concentration ranged from 48 to 102%. However, the agreement rates on the proportions of samples with concentrations surrounding 0.35 g/ml were >82% for all serotypes tested. Agreement between the two laboratories running the ECL assay was generally good: agreement on proportions of samples with concentrations surrounding 0.35 g/ml was in excess of 92%, and agreement on average antibody concentrations was within 31%. We conclude that the Meso Scale Discovery (MSD) platform provides a promising new technique for the simultaneous measurement of antipneumococcal antibodies.

Controlled Human Infection and Rechallenge with Streptococcus pneumoniae Reveals the Protective Efficacy of Carriage in Healthy Adults

“…Briefly, type 6B Streptococcus pneumoniae were instilled in 100 ml to each naris. Samples were obtained 1 week before and at 2, 7, and 14 days after pneumococcal inoculation for dose-ranging studies and 1 week before at 2,7,14,21,28,35, and 42 days in a longterm carriage study (ltcm) (Figure 1). For rechallenge experiments, previously colonized volunteers were reinoculated with the 6B strain.…”

“…We measured anti-capsular polysaccharide (PS) IgG by the standard World Health Organization ELISA method (21). The Meso Scale Discovery (MSD) technology (21) was used to determine antibody levels for 27 pneumococcal proteins (Table E1) before and after carriage or Figure 2.…”

TLR7/8 adjuvant overcomes newborn hyporesponsiveness to pneumococcal conjugate vaccine at birth

“…Ab response in infant monkey sera was measured in a 96-well electrochemiluminescence multiplex assay employing Meso Scale Discovery (MSD) technology, as previously described (55,56). Two 10-spot (per single microtiter well) 96-well plates were used to monitor Ab responses to all 13 pneumococcal serotypes.…”

“…A Sulfo-tag-labeled goat anti-human IgG that emits light upon electrochemical stimulation was used as a secondary Ab. The total IgG concentration in rhesus serum was calculated with MSD Workbench v. 3 software using the human antipneumococcal reference serum, lot 89SF-2 (Lederle-Praxis Biologicals) (56), and 007SP (57), as controls. Pneumococcal opsonophagocytosis assays were conducted at the Laboratory of Moon Nahm (University of Alabama; Birmingham, Alabama, USA).…”

Polysaccharide-Specific Memory B Cells Predict Protection against Experimental Human Pneumococcal Carriage

“…Antipneumococcal capsular PS antibodies were determined using the World Health Organization internationally standardized method and reagents (16). For full details, see METHODS in the online supplement.…”