ehealth digital library

Digital library of
the Tanzania
health
community

Effect of Ingested Human Antibodies Induced by RTS, S/AS01 Malaria Vaccination in Children on Plasmodium Falciparum oocyst Formation and Sporogony in Mosquitoes.

Miura, K., Jongert, E., Deng, B., Zhou, L., Lusingu, J. P., Drakeley, C. J., Fay, M. P., Long, C. A. and Vekemans, J. (2014) Effect of Ingested Human Antibodies Induced by RTS, S/AS01 Malaria Vaccination in Children on Plasmodium Falciparum oocyst Formation and Sporogony in Mosquitoes. Malaria journal, 13 (1). p. 263. ISSN 1475-2875

[img]
Preview
PDF
Kazutoyo_Miura.pdf - Published Version
Available under License Creative Commons Attribution Non-commercial.

Download (82kB)

Abstract

The circumsporozoite protein (CS protein) on the malaria parasites in mosquitoes plays an important role in sporogony in mosquitoes. The RTS,S/AS01 malaria vaccine candidate, which has shown significant efficacy against clinical malaria in a large Phase 3 trial, targets the Plasmodium falciparum CS protein, but the ability of serum from vaccinated individuals to inhibit sporogony in mosquitoes has not been evaluated. Previously a double-blind, randomized trial of RTS,S/AS01 vaccine, as compared with rabies vaccine, in five- to 17-month old children in Tanzania was conducted. In this study, polyclonal human antibodies were purified from the pools of sera taken one month after the third vaccination. IgGs were purified from four pools of sera from 25 RTS,S/AS01 vaccinated children each, and two pools of sera from 25 children vaccinated with rabies vaccine each. The ability of antibodies to inhibit P. falciparum oocyst formation and/or sporogony in the mosquito host was evaluated by a standard membrane-feeding assay. The test antibodies were fed on day 0 (at the same time as the gametocyte feed), or on days 3 or 6 (serial-feed experiments). The oocyst and sporozoite counts were performed on days 8 and 16, respectively. In addition, two human anti-CS monoclonal antibodies (mAb) and a control mAb were also evaluated. Polyclonal anti-CS IgG preparations from RTS,S-vaccinated children tested at concentrations of 149-210 ELISA units (EU)/ml did not show significant inhibition in oocyst and sporozoite formation when the antibodies were fed with gametocytes at the same time, or later (serial-feed experiments). Similarly, anti-CS mAbs tested at 6,421 or 7,122 EU/ml did not show reduction in oocyst and sporozoite formation. This study does not support the concept that anti-CS antibodies induced by the RTS,S/AS01 vaccines in humans noticeably reduce malaria transmission by blocking P. falciparum sporozoite development or salivary gland invasion in mosquitoes when taken up during feeding.

Item Type: Article
Keywords: RTS,S/AS01, Oocyst formation, Sporogony, Standard membrane feeding assay
Subjects: Malaria > Vaccines
Divisions: National Institute for Medical Research
Depositing User: Mr Joseph Madata
Date Deposited: 21 Jul 2014 06:46
Last Modified: 21 Jul 2014 06:46
URI: http://ihi.eprints.org/id/eprint/2739

Actions (login required)

Edit Item Edit Item

Downloads

Downloads per month over past year

View more statistics