A monoclonal antibody-based immunoassay to measure the antibody response against the repeat region of the circumsporozoite protein of Plasmodium falciparum

Malaria Journal

Methodology

Geert Leroux-Roels¹  Kristina Radin¹  Frederic Clement¹  Erik Jongert²  Franck Lemiale³  Christian Ockenhouse³  Yann G. J. Sterckx⁴  Jason Regules⁵ 

[1] Center for Vaccinology (CEVAC), Ghent University, Ghent, Belgium;GSK Vaccines, Rue de l’Institut 89, B-1330, Rixensart, Belgium;PATH Malaria Vaccine Initiative (MVI), 455 Massachusetts Avenue NW, 20001, Washington, DC, USA;Structural Biology Research Center (SBRC), VIB, Pleinlaan 2, B-1050, Brussels, Belgium;Research Unit for Cellular and Molecular Immunology (CMIM), VUB, Pleinlaan 2, B-1050, Brussels, Belgium;Walter Reed Army Institute of Research (WRAIR), 503 Robert Grant Ave., 20910, Silver Spring, MD, USA;

关键词: Malaria;    Competition ELISA;    Enzyme-linked immunosorbent assay;    Immunoassay;    Circumsporozoite protein;   

DOI  :  10.1186/s12936-016-1596-8

 received in 2016-07-17, accepted in 2016-10-31,  发布年份 2016

来源: Springer

【 摘 要 】

BackgroundThe malaria vaccine candidate RTS,S/AS01 (GSK Vaccines) induces high IgG concentration against the circumsporozoite protein (CSP) of Plasmodium falciparum. In human vaccine recipients circulating anti-CSP antibody concentrations are associated with protection against infection but appear not to be the correlate of protection. However, in a humanized mouse model of malaria infection prophylactic administration of a human monoclonal antibody (MAL1C), derived from a RTS,S/AS01-immunized volunteer, directed against the CSP repeat region, conveyed full protection in a dose-dependent manner suggesting that antibodies alone are able to prevent P. falciparum infection when present in sufficiently high concentrations. A competition ELISA was developed to measure the presence of MAL1C-like antibodies in polyclonal sera from RTS,S/AS01 vaccine recipients and study their possible contribution to protection against infection.ResultsMAL1C-like antibodies present in polyclonal vaccine-induced sera were evaluated for their ability to compete with biotinylated monoclonal antibody MAL1C for binding sites on the capture antigen consisting of the recombinant protein encompassing 32 NANP repeats of CSP (R32LR). Serum samples were taken at different time points from participants in two RTS,S/AS01 vaccine studies (NCT01366534 and NCT01857869). Vaccine-induced protection status of the study participants was determined based on the outcome of experimental challenge with infected mosquito bites after vaccination. Optimal conditions were established to reliably detect MAL1C-like antibodies in polyclonal sera. Polyclonal anti-CSP antibodies and MAL1C-like antibody content were measured in 276 serum samples from RTS,S/AS01 vaccine recipients using the standard ELISA and MAL-1C competition ELISA, respectively. A strong correlation was observed between the results from these assays. However, no correlation was found between the results of either assay and protection against infection.ConclusionsThe competition ELISA to measure MAL1C-like antibodies in polyclonal sera from RTS,S/AS01 vaccine recipients was robust and reliable but did not reveal the elusive correlate of protection.

【 授权许可】

CC BY   
© The Author(s) 2016