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Article ; Online: The P. falciparum CSP repeat region contains three distinct epitopes required for protection by antibodies in vivo.

Yevel Flores-Garcia / Lawrence T Wang / Minah Park / Beejan Asady / Azza H Idris / Neville K Kisalu / Christian Muñoz / Lais S Pereira / Joseph R Francica / Robert A Seder / Fidel Zavala

PLoS Pathogens, Vol 17, Iss 11, p e

2021 Volume 1010042

Abstract: Rare and potent monoclonal antibodies (mAbs) against the Plasmodium falciparum (Pf) circumsporozoite protein (CSP) on infective sporozoites (SPZ) preferentially bind the PfCSP junctional tetrapeptide NPDP or NVDP minor repeats while cross-reacting with ... ...

Abstract	Rare and potent monoclonal antibodies (mAbs) against the Plasmodium falciparum (Pf) circumsporozoite protein (CSP) on infective sporozoites (SPZ) preferentially bind the PfCSP junctional tetrapeptide NPDP or NVDP minor repeats while cross-reacting with NANP central repeats in vitro. The extent to which each of these epitopes is required for protection in vivo is unknown. Here, we assessed whether junction-, minor repeat- and central repeat-preferring human mAbs (CIS43, L9 and 317 respectively) bound and protected against in vivo challenge with transgenic P. berghei (Pb) SPZ expressing either PfCSP with the junction and minor repeats knocked out (KO), or PbCSP with the junction and minor repeats knocked in (KI). In vivo protection studies showed that the junction and minor repeats are necessary and sufficient for CIS43 and L9 to neutralize KO and KI SPZ, respectively. In contrast, 317 required major repeats for in vivo protection. These data establish that human mAbs can prevent malaria infection by targeting three different protective epitopes (NPDP, NVDP, NANP) in the PfCSP repeat region. This report will inform vaccine development and the use of mAbs to passively prevent malaria.
Keywords	Immunologic diseases. Allergy ; RC581-607 ; Biology (General) ; QH301-705.5
Subject code	572
Language	English
Publishing date	2021-11-01T00:00:00Z
Publisher	Public Library of Science (PLoS)
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Cytotoxicity of human antibodies targeting the circumsporozoite protein is amplified by 3D substrate and correlates with protection

Manuela C. Aguirre-Botero / Lawrence T. Wang / Pauline Formaglio / Eduardo Aliprandini / Jean-Michel Thiberge / Arne Schön / Yevel Flores-Garcia / Shamika Mathis-Torres / Barbara J. Flynn / Lais da Silva Pereira / Yann Le Duff / Mathew Hurley / Adéla Nacer / Paul W. Bowyer / Fidel Zavala / Azza H. Idris / Joseph R. Francica / Robert A. Seder / Rogerio Amino

Cell Reports, Vol 42, Iss 7, Pp 112681- (2023)

2023

Abstract: Summary: Human monoclonal antibodies (hmAbs) targeting the Plasmodium falciparum circumsporozoite protein (PfCSP) on the sporozoite surface are a promising tool for preventing malaria infection. However, their mechanisms of protection remain unclear. ... ...

Abstract	Summary: Human monoclonal antibodies (hmAbs) targeting the Plasmodium falciparum circumsporozoite protein (PfCSP) on the sporozoite surface are a promising tool for preventing malaria infection. However, their mechanisms of protection remain unclear. Here, using 13 distinctive PfCSP hmAbs, we provide a comprehensive view of how PfCSP hmAbs neutralize sporozoites in host tissues. Sporozoites are most vulnerable to hmAb-mediated neutralization in the skin. However, rare but potent hmAbs additionally neutralize sporozoites in the blood and liver. Efficient protection in tissues mainly associates with high-affinity and high-cytotoxicity hmAbs inducing rapid parasite loss-of-fitness in the absence of complement and host cells in vitro. A 3D-substrate assay greatly enhances hmAb cytotoxicity and mimics the skin-dependent protection, indicating that the physical stress imposed on motile sporozoites by the skin is crucial for unfolding the protective potential of hmAbs. This functional 3D cytotoxicity assay can thus be useful for downselecting potent anti-PfCSP hmAbs and vaccines.
Keywords	CP: Immunology ; Biology (General) ; QH301-705.5
Subject code	570
Language	English
Publishing date	2023-07-01T00:00:00Z
Publisher	Elsevier
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Protective effects of combining monoclonal antibodies and vaccines against the Plasmodium falciparum circumsporozoite protein.

Lawrence T Wang / Lais S Pereira / Patience K Kiyuka / Arne Schön / Neville K Kisalu / Rachel Vistein / Marlon Dillon / Brian G Bonilla / Alvaro Molina-Cruz / Carolina Barillas-Mury / Joshua Tan / Azza H Idris / Joseph R Francica / Robert A Seder

PLoS Pathogens, Vol 17, Iss 12, p e

2021 Volume 1010133

Abstract: Combinations of monoclonal antibodies (mAbs) against different epitopes on the same antigen synergistically neutralize many viruses. However, there are limited studies assessing whether combining human mAbs against distinct regions of the Plasmodium ... ...

Abstract	Combinations of monoclonal antibodies (mAbs) against different epitopes on the same antigen synergistically neutralize many viruses. However, there are limited studies assessing whether combining human mAbs against distinct regions of the Plasmodium falciparum (Pf) circumsporozoite protein (CSP) enhances in vivo protection against malaria compared to each mAb alone or whether passive transfer of PfCSP mAbs would improve protection following vaccination against PfCSP. Here, we isolated a panel of human mAbs against the subdominant C-terminal domain of PfCSP (C-CSP) from a volunteer immunized with radiation-attenuated Pf sporozoites. These C-CSP-specific mAbs had limited binding to sporozoites in vitro that was increased by combination with neutralizing human "repeat" mAbs against the NPDP/NVDP/NANP tetrapeptides in the central repeat region of PfCSP. Nevertheless, passive transfer of repeat- and C-CSP-specific mAb combinations did not provide enhanced protection against in vivo sporozoite challenge compared to repeat mAbs alone. Furthermore, combining potent repeat-specific mAbs (CIS43, L9, and 317) that respectively target the three tetrapeptides (NPDP/NVDP/NANP) did not provide additional protection against in vivo sporozoite challenge. However, administration of either CIS43, L9, or 317 (but not C-CSP-specific mAbs) to mice that had been immunized with R21, a PfCSP-based virus-like particle vaccine that induces polyclonal antibodies against the repeat region and C-CSP, provided enhanced protection against sporozoite challenge when compared to vaccine or mAbs alone. Collectively, this study shows that while combining mAbs against the repeat and C-terminal regions of PfCSP provide no additional protection in vivo, repeat mAbs do provide increased protection when combined with vaccine-induced polyclonal antibodies. These data should inform the implementation of PfCSP human mAbs alone or following vaccination to prevent malaria infection.
Keywords	Immunologic diseases. Allergy ; RC581-607 ; Biology (General) ; QH301-705.5
Language	English
Publishing date	2021-12-01T00:00:00Z
Publisher	Public Library of Science (PLoS)
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Enhancing durability of CIS43 monoclonal antibody by Fc mutation or AAV delivery for malaria prevention

Neville K. Kisalu / Lais D. Pereira / Keenan Ernste / Yevel Flores-Garcia / Azza H. Idris / Mangaiarkarasi Asokan / Marlon Dillon / Scott MacDonald / Wei Shi / Xuejun Chen / Amarendra Pegu / Arne Schön / Fidel Zavala / Alejandro B. Balazs / Joseph R. Francica / Robert A. Seder

JCI Insight, Vol 6, Iss

2021 Volume 3

Abstract: CIS43 is a potent neutralizing human mAb that targets a highly conserved “junctional” epitope in the Plasmodium falciparum (Pf) circumsporozoite protein (PfCSP). Enhancing the durability of CIS43 in vivo will be important for clinical translation. Here, ... ...

Abstract	CIS43 is a potent neutralizing human mAb that targets a highly conserved “junctional” epitope in the Plasmodium falciparum (Pf) circumsporozoite protein (PfCSP). Enhancing the durability of CIS43 in vivo will be important for clinical translation. Here, 2 approaches were used to improve the durability of CIS43 in vivo while maintaining potent neutralization. First, the Fc domain was modified with the LS mutations (CIS43LS) to increase CIS43 binding affinity for the neonatal Fc receptor (FcRn). CIS43LS and CIS43 showed comparable in vivo protective efficacy. CIS43LS had 9- to 13-fold increased binding affinity for human (6.2 nM versus 54.2 nM) and rhesus (25.1 nM versus 325.8 nM) FcRn at endosomal pH 6.0 compared with CIS43. Importantly, the half-life of CIS43LS in rhesus macaques increased from 22 days to 39 days compared with CIS43. The second approach for sustaining antibody levels of CIS43 in vivo is through adeno-associated virus (AAV) expression. Mice administered once with AAV-expressing CIS43 had sustained antibody levels of approximately 300 μg/mL and mediated protection against sequential malaria challenges up to 36 weeks. Based on these data, CIS43LS has advanced to phase I clinical trials, and AAV delivery provides a potential next-generation approach for malaria prevention.
Keywords	Infectious disease ; Medicine ; R
Subject code	616
Language	English
Publishing date	2021-02-01T00:00:00Z
Publisher	American Society for Clinical investigation
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Delayed boosting improves human antigen-specific Ig and B cell responses to the RH5.1/AS01B malaria vaccine

Carolyn M. Nielsen / Jordan R. Barrett / Christine Davis / Jonathan K. Fallon / Cyndi Goh / Ashlin R. Michell / Catherine Griffin / Andrew Kwok / Carolin Loos / Samuel Darko / Farida Laboune / Mehmet Tekman / Ababacar Diouf / Kazutoyo Miura / Joseph R. Francica / Amy Ransier / Carole A. Long / Sarah E. Silk / Ruth O. Payne /

Angela M. Minassian / Douglas A. Lauffenburger / Robert A. Seder / Daniel C. Douek / Galit Alter / Simon J. Draper

JCI Insight, Vol 8, Iss

2023 Volume 2

Abstract: Modifications to vaccine delivery that increase serum antibody longevity are of great interest for maximizing efficacy. We have previously shown that a delayed fractional (DFx) dosing schedule (0-1-6 month) — using AS01B-adjuvanted RH5.1 malaria antigen — ...

Abstract	Modifications to vaccine delivery that increase serum antibody longevity are of great interest for maximizing efficacy. We have previously shown that a delayed fractional (DFx) dosing schedule (0-1-6 month) — using AS01B-adjuvanted RH5.1 malaria antigen — substantially improves serum IgG durability as compared with monthly dosing (0-1-2 month; NCT02927145). However, the underlying mechanism and whether there are wider immunological changes with DFx dosing were unclear. Here, PfRH5-specific Ig and B cell responses were analyzed in depth through standardized ELISAs, flow cytometry, systems serology, and single-cell RNA-Seq (scRNA-Seq). Data indicate that DFx dosing increases the magnitude and durability of circulating PfRH5-specific B cells and serum IgG1. At the peak antibody magnitude, DFx dosing was distinguished by a systems serology feature set comprising increased FcRn binding, IgG avidity, and proportion of G2B and G2S2F IgG Fc glycans, alongside decreased IgG3, antibody-dependent complement deposition, and proportion of G1S1F IgG Fc glycan. Concomitantly, scRNA-Seq data show a higher CDR3 percentage of mutation from germline and decreased plasma cell gene expression in circulating PfRH5-specific B cells. Our data, therefore, reveal a profound impact of DFx dosing on the humoral response and suggest plausible mechanisms that could enhance antibody longevity, including improved FcRn binding by serum Ig and a potential shift in the underlying cellular response from circulating short-lived plasma cells to nonperipheral long-lived plasma cells.
Keywords	Immunology ; Vaccines ; Medicine ; R
Subject code	571
Language	English
Publishing date	2023-01-01T00:00:00Z
Publisher	American Society for Clinical investigation
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Design of Alphavirus Virus-Like Particles Presenting Circumsporozoite Junctional Epitopes That Elicit Protection against Malaria

Vaccines, Vol 9, Iss 272, p

2021 Volume 272

Abstract: The most advanced malaria vaccine, RTS,S, includes the central repeat and C-terminal domains of the Plasmodium falciparum circumsporozoite protein (PfCSP). We have recently isolated human antibodies that target the junctional region between the N- ... ...

Abstract	The most advanced malaria vaccine, RTS,S, includes the central repeat and C-terminal domains of the Plasmodium falciparum circumsporozoite protein (PfCSP). We have recently isolated human antibodies that target the junctional region between the N-terminal and repeat domains that are not included in RTS,S. Due to the fact that these antibodies protect against malaria challenge in mice, their epitopes could be effective vaccine targets. Here, we developed immunogens displaying PfCSP junctional epitopes by genetic fusion to either the N-terminus or B domain loop of the E2 protein from chikungunya (CHIK) alphavirus and produced CHIK virus-like particles (CHIK-VLPs). The structural integrity of these junctional-epitope–CHIK-VLP immunogens was confirmed by negative-stain electron microscopy. Immunization of these CHIK-VLP immunogens reduced parasite liver load by up to 95% in a mouse model of malaria infection and elicited better protection than when displayed on keyhole limpet hemocyanin, a commonly used immunogenic carrier. Protection correlated with PfCSP serum titer. Of note, different junctional sequences elicited qualitatively different reactivities to overlapping PfCSP peptides. Overall, these results show that the junctional epitopes of PfCSP can induce protective responses when displayed on CHIK-VLP immunogens and provide a basis for the development of a next generation malaria vaccine to expand the breadth of anti-PfCSP immunity.
Keywords	junctional epitope ; malaria ; neutralizing antibodies ; parasite ; Plasmodium falciparum ; vaccines ; Medicine ; R
Subject code	572
Language	English
Publishing date	2021-03-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Star nanoparticles delivering HIV-1 peptide minimal immunogens elicit near-native envelope antibody responses in nonhuman primates.

Joseph R Francica / Richard Laga / Geoffrey M Lynn / Gabriela Mužíková / Ladislav Androvič / Baptiste Aussedat / William E Walkowicz / Kartika Padhan / Ramiro Andrei Ramirez-Valdez / Robert Parks / Stephen D Schmidt / Barbara J Flynn / Yaroslav Tsybovsky / Guillaume B E Stewart-Jones / Kevin O Saunders / Faezzah Baharom / Constantinos Petrovas / Barton F Haynes / Robert A Seder

PLoS Biology, Vol 17, Iss 6, p e

2019 Volume 3000328

Abstract: Peptide immunogens provide an approach to focus antibody responses to specific neutralizing sites on the HIV envelope protein (Env) trimer or on other pathogens. However, the physical characteristics of peptide immunogens can limit their pharmacokinetic ... ...

Abstract	Peptide immunogens provide an approach to focus antibody responses to specific neutralizing sites on the HIV envelope protein (Env) trimer or on other pathogens. However, the physical characteristics of peptide immunogens can limit their pharmacokinetic and immunological properties. Here, we have designed synthetic "star" nanoparticles based on biocompatible N-[(2-hydroxypropyl)methacrylamide] (HPMA)-based polymer arms extending from a poly(amidoamine) (PAMAM) dendrimer core. In mice, these star nanoparticles trafficked to lymph nodes (LNs) by 4 hours following vaccination, where they were taken up by subcapsular macrophages and then resident dendritic cells (DCs). Immunogenicity optimization studies revealed a correlation of immunogen density with antibody titers. Furthermore, the co-delivery of Env variable loop 3 (V3) and T-helper peptides induced titers that were 2 logs higher than if the peptides were given in separate nanoparticles. Finally, we performed a nonhuman primate (NHP) study using a V3 glycopeptide minimal immunogen that was structurally optimized to be recognized by Env V3/glycan broadly neutralizing antibodies (bnAbs). When administered with a potent Toll-like receptor (TLR) 7/8 agonist adjuvant, these nanoparticles elicited high antibody binding titers to the V3 site. Similar to human V3/glycan bnAbs, certain monoclonal antibodies (mAbs) elicited by this vaccine were glycan dependent or targeted the GDIR peptide motif. To improve affinity to native Env trimer affinity, nonhuman primates (NHPs) were boosted with various SOSIP Env proteins; however, significant neutralization was not observed. Taken together, this study provides a new vaccine platform for administration of glycopeptide immunogens for focusing immune responses to specific bnAb epitopes.
Keywords	Biology (General) ; QH301-705.5
Subject code	570
Language	English
Publishing date	2019-06-01T00:00:00Z
Publisher	Public Library of Science (PLoS)
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Steric shielding of surface epitopes and impaired immune recognition induced by the ebola virus glycoprotein.

Joseph R Francica / Angel Varela-Rohena / Andrew Medvec / Gabriela Plesa / James L Riley / Paul Bates

PLoS Pathogens, Vol 6, Iss 9, p e

2010 Volume 1001098

Abstract: Many viruses alter expression of proteins on the surface of infected cells including molecules important for immune recognition, such as the major histocompatibility complex (MHC) class I and II molecules. Virus-induced downregulation of surface proteins ...

Abstract	Many viruses alter expression of proteins on the surface of infected cells including molecules important for immune recognition, such as the major histocompatibility complex (MHC) class I and II molecules. Virus-induced downregulation of surface proteins has been observed to occur by a variety of mechanisms including impaired transcription, blocks to synthesis, and increased turnover. Viral infection or transient expression of the Ebola virus (EBOV) glycoprotein (GP) was previously shown to result in loss of staining of various host cell surface proteins including MHC1 and β1 integrin; however, the mechanism responsible for this effect has not been delineated. In the present study we demonstrate that EBOV GP does not decrease surface levels of β1 integrin or MHC1, but rather impedes recognition by steric occlusion of these proteins on the cell surface. Furthermore, steric occlusion also occurs for epitopes on the EBOV glycoprotein itself. The occluded epitopes in host proteins and EBOV GP can be revealed by removal of the surface subunit of GP or by removal of surface N- and O- linked glycans, resulting in increased surface staining by flow cytometry. Importantly, expression of EBOV GP impairs CD8 T-cell recognition of MHC1 on antigen presenting cells. Glycan-mediated steric shielding of host cell surface proteins by EBOV GP represents a novel mechanism for a virus to affect host cell function, thereby escaping immune detection.
Keywords	Immunologic diseases. Allergy ; RC581-607 ; Biology (General) ; QH301-705.5
Subject code	570
Language	English
Publishing date	2010-09-01T00:00:00Z
Publisher	Public Library of Science (PLoS)
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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