IgG2 Antibodies against a Clinical Grade Plasmodium falciparum CSP Vaccine Antigen Associate with Protection against Transgenic Sporozoite Challenge in Mice
Author(s)
Type
Journal Article
Abstract
The availability of a highly purified and well characterized circumsporozoite protein (CSP) is essential to improve upon the partial success of recombinant CSP-based malaria vaccine candidates. Soluble, near full-length, Plasmodium falciparum CSP vaccine antigen (CS/D) was produced in E. coli under bio-production conditions that comply with current Good Manufacturing Practices (cGMP). A mouse immunogenicity study was conducted using a stable oil-in-water emulsion (SE) of CS/D in combination with the Toll-Like Receptor 4 (TLR4) agonist Glucopyranosyl Lipid A (GLA/SE), or one of two TLR7/8 agonists: R848 (un-conjugated) or 3M-051 (covalently conjugated). Compared to Alum and SE, GLA/SE induced higher CS/D specific antibody response in Balb/c mice. Subclass analysis showed higher IgG2:IgG1 ratio of GLA/SE induced antibodies as compared to Alum and SE. TLR synergy was not observed when soluble R848 was mixed with GLA/SE. Antibody response of 3M051 formulations in Balb/c was similar to GLA/SE, except for the higher IgG2:IgG1 ratio and a trend towards higher T cell responses in 3M051 containing groups. However, no synergistic enhancement of antibody and T cell response was evident when 3M051 conjugate was mixed with GLA/SE. In C57Bl/6 mice, CS/D adjuvanted with 3M051/SE or GLA/SE induced higher CSP repeat specific titers compared to SE. While, 3M051 induced antibodies had high IgG2c:IgG1 ratio, GLA/SE promoted high levels of both IgG1 and IgG2c. GLA/SE also induced more potent T-cell responses compared to SE in two independent C57/BL6 vaccination studies, suggesting a balanced and productive TH1/TH2 response. GLA and 3M-051 similarly enhanced the protective efficacy of CS/D against challenge with a transgenic P. berghei parasite and most importantly, high levels of cytophilic IgG2 antibodies were associated with protection in this model. Our data indicated that the cGMP-grade, soluble CS/D antigen combined with the TLR4-containing adjuvant GLA/SE warrants further evaluation for protective responses in humans.
Date Issued
2014-10-24
Date Acceptance
2014-09-19
Citation
PLOS One, 2014, 9 (10)
ISSN
1932-6203
Publisher
Public Library of Science
Journal / Book Title
PLOS One
Volume
9
Issue
10
Copyright Statement
This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.
Subjects
Science & Technology
Multidisciplinary Sciences
Science & Technology - Other Topics
T-CELL RESPONSES
MALARIA-NAIVE ADULTS
RECEPTOR 4 AGONIST
PHASE 2A TRIAL
CIRCUMSPOROZOITE PROTEIN
ESCHERICHIA-COLI
DENDRITIC CELLS
SIGNALING PATHWAY
INFLUENZA VACCINE
TLR SYNERGY
Animals
Antibodies, Monoclonal
Antibodies, Protozoan
Antigens, CD86
Antigens, Protozoan
B-Lymphocytes
Dose-Response Relationship, Immunologic
Enzyme-Linked Immunosorbent Assay
Immunity
Immunoglobulin G
Ligands
Malaria Vaccines
Malaria, Falciparum
Mice, Inbred BALB C
Mice, Inbred C57BL
Plasmodium falciparum
Protozoan Proteins
Sporozoites
Toll-Like Receptors
Vaccination
General Science & Technology
MD Multidisciplinary
Publication Status
Published
Article Number
e111020