Plasmodium falciparum: A Comparison of the Activity of Pfs230-Specific Antibodies in an Assay of Transmission-Blocking Immunity and Specific Competition ELISAs

Roeffen, Will; Beckers, Pascal; Teelen, Karina; Lensen, T; Sauerwein, Robert W.; Meuwissen, J. H. E. T.; Eling, W.M.C.

doi:10.1006/expr.1995.1003

Cited by 47 publications

(63 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Gametocytes were isolated as described previously (13). The purified gametocytes were (a) used directly, in immunofluorescence assays (see below), or (b) stored at Ϫ70°C until used.…”

Section: Methodsmentioning

confidence: 99%

Recombinant Human Antibodies Specific for the Pfs48/45 Protein of the Malaria Parasite Plasmodium falciparum

Roeffen¹,

Raats

Teelen³

et al. 2001

Journal of Biological Chemistry

View full text Add to dashboard Cite

We report the first construction of two combinatorial human phage display libraries derived from malariaimmune patients. Specific single-chain Fv fragments (scFv) against Pfs48/45, a gamete surface protein of the sexual stages of Plasmodium falciparum, were selected and analyzed extensively. The selected scFv reacted with the surface of extracellular sexual forms of the parasite and showed Pfs48/45 reactivity on immunoblot. The scFv inhibit binding of human malaria sera to native Pfs48/45 from gametocytes. Moreover, the scFv bind to target epitopes of Pfs48/45 exposed in natural infections. Sequence analysis of eight scFv clones specific for epitope III of Pfs48/45 revealed that these clones could be divided into one V H family-derived germ-line gene (V H 1) and two V L family segments (V L 2 and V K I).Plasmodium malaria is transmitted to the Anopheles vector when mosquitoes ingest blood that contains gametocytes. Gametocytes of Plasmodium falciparum synthesize Pfs230 and Pfs48/45, which are expressed on the surface of macrogametes and zygotes and a target for transmission-blocking immunity. Antibodies in the ingested bloodmeal can bind to sexual forms in the mosquito gut and prevent oocyst development (1-3). A panel of murine and rat monoclonal antibodies (mAbs) 1 has been produced against Pfs48/45 and has recognized at least five different epitopes. Some of these mAbs showed transmissionblocking activity (3-6).Transmission-blocking vaccines directed against sexual stage-specific antigens are designed to arrest the development of sporogonic stages inside the mosquito, thereby reducing the infectivity of the mosquito and thereby prohibiting the spread of the disease. Major obstacles in developing a transmissionblocking vaccine are the production of correctly folded Pfs48/45 because of the conformational nature of the Pfs48/45 epitope. A large panel of anti-Pfs48/45 mAbs was needed for a number of reasons: 1) to elucidate the relationship between Pfs48/45 and Pfs230 and 2) to measure and characterize anti-Pfs48/45 antibodies in experimental and field sera.Phage display antibodies offer a method for the production of high affinity single chain variable fragment (scFv) derivatives of human antibodies of "natural host" origin (for reviews, see Ref. 7). Our objective was to produce human mAbs against Pfs48/45, a sexual stage antigen of P. falciparum. For this study combinatorial phage display libraries were constructed using B-lymphocytes from P. falciparum gametocyte carriers with transmission-blocking immunity. Subsequently, phages were selected from these libraries by panning on Pfs48/45 antigen and phages bound to the antigen eluted by competition with mAbs (8). This method resulted in human scFv antibodies directed against epitope III of Pfs48/45. MATERIALS AND METHODSParasites-Mature P. falciparum gametocytes (NF54 strain) were produced in a semi-automated system as described previously (12). Gametocytes were isolated as described previously (13). The purified gametocytes were (a) used directly, in immunofluor...

show abstract

“…Gametocytes were isolated as described previously (13). The purified gametocytes were (a) used directly, in immunofluorescence assays (see below), or (b) stored at Ϫ70°C until used.…”

Section: Methodsmentioning

confidence: 99%

Recombinant Human Antibodies Specific for the Pfs48/45 Protein of the Malaria Parasite Plasmodium falciparum

Roeffen¹,

Raats

Teelen³

et al. 2001

Journal of Biological Chemistry

View full text Add to dashboard Cite

show abstract

“…Pfs230 may be involved in protection of the parasite from the contents of the blood meal, in fertilization (514), or in the formation of exflagellation centers (137). Antibodies against Pfs230 can reduce oocyst development (369,514) by lysis of gametes in a complement-dependent manner (196,369,376,388). The presence of complement is essential for the transmission-blocking activities of Pfs230.…”

Section: Immune Responses Influencing Gametocyte Infectivitymentioning

confidence: 99%

Epidemiology and Infectivity of Plasmodium falciparum and Plasmodium vivax Gametocytes in Relation to Malaria Control and Elimination

2011

View full text Add to dashboard Cite

SUMMARY Malaria remains a major cause of morbidity and mortality in the tropics, with Plasmodium falciparum responsible for the majority of the disease burden and P. vivax being the geographically most widely distributed cause of malaria. Gametocytes are the sexual-stage parasites that infect Anopheles mosquitoes and mediate the onward transmission of the disease. Gametocytes are poorly studied despite this crucial role, but with a recent resurgence of interest in malaria elimination, the study of gametocytes is in vogue. This review highlights the current state of knowledge with regard to the development and longevity of P. falciparum and P. vivax gametocytes in the human host and the factors influencing their distribution within endemic populations. The evidence for immune responses, antimalarial drugs, and drug resistance influencing infectiousness to mosquitoes is reviewed. We discuss how the application of molecular techniques has led to the identification of submicroscopic gametocyte carriage and to a reassessment of the human infectious reservoir. These components are drawn together to show how control measures that aim to reduce malaria transmission, such as mass drug administration and a transmission-blocking vaccine, might better be deployed.

show abstract

“…Pfs230 is initially a 360-kDa gametocyte surface protein that is proteolytically processed during development at the amino terminus (18). Polyclonal (19,20) and monoclonal (14,21) antibodies have been shown to block parasite transmission using the ex vivo SMFA in a complement-dependent manner. Pfs230 has been speculated to have a male gamete function because parasites with a truncated form of Pfs230 were shown to adhere to uninfected erythrocytes, even though their capacity to infect mosquitoes was severely decreased by greater than 95% (22).…”

mentioning

confidence: 99%

Structural and Immunological Characterization of Recombinant 6-Cysteine Domains of the Plasmodium falciparum Sexual Stage Protein Pfs230

MacDonald

Nguyen

Shimp

et al. 2016

Journal of Biological Chemistry

122

View full text Add to dashboard Cite

Development of a Plasmodium falciparum (Pf) transmission blocking vaccine (TBV) has the potential to significantly impact malaria control. Antibodies elicited against sexual stage proteins in the human bloodstream are taken up with the blood meal of the mosquitoes and inactivate parasite development in the mosquito. In a phase 1 trial, a leading TBV identified as Pfs25-EPA/Alhydrogel appeared safe and immunogenic, however, the level of Pfs25-specific antibodies were likely too low for an effective vaccine. Pfs230, a 230-kDa sexual stage protein expressed in gametocytes is an alternative vaccine candidate. A unique 6-cysteine-rich domain structure within Pfs230 have thwarted its recombinant expression and characterization for clinical evaluation for nearly a quarter of a century. Here, we report on the identification, biochemical, biophysical, and immunological characterization of recombinant Pfs230 domains. Rabbit antibodies generated against recombinant Pfs230 domains blocked mosquito transmission of a laboratory strain and two field isolates using an ex vivo assay. A planned clinical trial of the Pfs230 vaccine is a significant step toward the potential development of a transmission blocking vaccine to eliminate malaria.Development of a malaria vaccine that effectively protects against parasite infection of both the natural host, Anopheles mosquitoes, and its secondary host, man, would effectively disrupt transmission and clinical disease. The most well known investigational vaccine against Plasmodium falciparum malaria that recently received a positive scientific opinion from the Committee for Medicinal Products for Human Use of the European Medicines Agency in July 2015, is identified as RTS,S (Mosquirix TM ). This vaccine targets the circumsporozoite protein that is present on the surface of the sporozoite, the parasite stage that infects man (1). RTS,S, a virus like-particle-based vaccine, is protective against clinical disease in about 30% of the young children who participated in a phase 3 trial (1, 2).Efforts toward development of a vaccine to disrupt parasite infection of the mosquito host, also identified as a transmission blocking vaccine have to date only been able to evaluate a sexual stage-specific protein, Pfs25, 2 which is a 25-kDa protein expressed on the zygote and ookinete surfaces. A phase 1 study demonstrated that human antibodies raised against a recombinant Pfs25 (Pfs25H) protein formulated in Montanide ISA 51, a water-in-oil adjuvant formulation, were biologically active in an ex vivo feeding assay (3), however, this formulation was not deemed suitable for a public health vaccine. More recently, in preclinical studies, Pfs25H has been shown to have enhanced immunogenic properties when chemically conjugated to a carrier molecule such as Neisseria meningitis outer membrane protein complex (4), or Pseudomonas aeruginosa ExoProtein A (EPA) (5, 6). In particular, the chemically conjugated Pfs25-EPA has the biophysical features of a nanoparticle with a diameter of about 25 m in solution, simil...

show abstract

Plasmodium falciparum: A Comparison of the Activity of Pfs230-Specific Antibodies in an Assay of Transmission-Blocking Immunity and Specific Competition ELISAs

Cited by 47 publications

References 1 publication

Recombinant Human Antibodies Specific for the Pfs48/45 Protein of the Malaria Parasite Plasmodium falciparum

Recombinant Human Antibodies Specific for the Pfs48/45 Protein of the Malaria Parasite Plasmodium falciparum

Epidemiology and Infectivity of Plasmodium falciparum and Plasmodium vivax Gametocytes in Relation to Malaria Control and Elimination

Structural and Immunological Characterization of Recombinant 6-Cysteine Domains of the Plasmodium falciparum Sexual Stage Protein Pfs230

Contact Info

Product

Resources

About