Correlations between three ELISA protocols measurements of RTS,S/AS01-induced anti-CSP IgG antibodies

• Published in: PloS one 2023-05, Vol.18 (5), p.e0286117
• Main Authors: Mugo, Robert M, Orindi, Benedict, Shee, Faiz M, Bellamy, Duncan, Mwacharo, Jedidah, Ewer, Katie J, Bejon, Philip, Ndungu, Francis M
• Format: Article
• Language: English
• Subjects: AIDS vaccines; Antibodies; Antigens; Assaying; Automation; Biology and Life Sciences; Circumsporozoite protein; Clinical trials; Comparative analysis; Correlation; Diagnosis; Effectiveness; Enzyme-linked immunosorbent assay; Enzyme-Linked Immunosorbent Assay - methods; Enzymes; Equivalence; Ethics; Health aspects; Humans; IgG antibody; Immunoassays; Immunogenicity; Immunoglobulin G; Immunoglobulin G - analysis; Infant; Insecticides; Kenya; Licenses; Linear equations; Linearity; Malaria; Measurement; Medical research; Medicin och hälsovetenskap; Medicine and Health Sciences; Plasma; Prevention; Proteins; Regression models; Research and Analysis Methods; Research centers; Vaccine efficacy; Vaccines; Viral antibodies
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0286117

RTS,S/AS01 induced anti-circumsporozoite protein (CSP) IgG antibodies are associated with the vaccine efficacy. There is currently no international standardisation of the assays used in the measurement of anti-CSP IgG antibody concentrations for use in evaluations of the vaccine's immunogenicity and/or efficacy. Here, we compared the levels of RTS,S/AS01 induced anti-CSP IgG antibodies measured using three different enzyme-Linked ImmunoSorbent Assays (ELISA). 196 plasma samples were randomly selected from the 447 samples collected during the RTS,S/AS01 phase IIb trial in 2007 from Kenyan children aged between 5-17 months. The vaccine-induced anti-CSP IgG antibodies were then measured using two independently developed ELISA protocols ('Kilifi-RTS,S' and 'Oxford-R21') and compared to the results from the reference 'Ghent-RTS,S' protocol for the same participants. For each pair of protocols, a deming regression model was fitted. Linear equations were then derived to aid in conversions into equivalent ELISA units. The agreement was assessed using Bland and Altman method. The anti-CSP IgG antibodies measured from the three ELISA protocols were in agreement, and were positively and linearly correlated; 'Oxford' and 'Kilifi' r = 0.93 (95% CI 0.91-0.95), 'Oxford' and 'Ghent' r = 0.94 (95% CI: 0.92-0.96), and 'Kilifi' and 'Ghent' r = 0.97 (95% CI: 0.96-0.98), p