-
Trends in Parasitology May 2010Although the past decade has witnessed sequencing from an increasing number of parasites, modern high-throughput DNA sequencing technologies have the potential to... (Review)
Review
Although the past decade has witnessed sequencing from an increasing number of parasites, modern high-throughput DNA sequencing technologies have the potential to generate complete genome sequences at even higher rates. Along with the discovery of genes that might constitute potential targets for chemotherapy or vaccination, the need for novel protein expression platforms has become a pressing matter. In addition to reviewing the advantages and limitations of the currently available and emerging expression systems, we discuss novel approaches that could overcome current limitations, including the 'pseudoparasite' concept, an expression platform in which the choice of the surrogate organism is based on its phylogenetic affinity to the target parasite, while taking advantage of the whole engineered organism as a vaccination adjuvant.
Topics: Cell-Free System; Eukaryota; Gene Expression; Prokaryotic Cells; Protozoan Proteins; Protozoan Vaccines; Recombinant Proteins
PubMed: 20189877
DOI: 10.1016/j.pt.2010.02.004 -
Parasitology Research Jun 2019Coccidiosis is a major poultry disease which compromises animal welfare and costs the global chicken industry a huge economic loss. As a result, research entailing... (Review)
Review
Coccidiosis is a major poultry disease which compromises animal welfare and costs the global chicken industry a huge economic loss. As a result, research entailing coccidial control measures is crucial. Coccidiosis is caused by Eimeria parasites that are highly immunogenic. Consequently, a low dosage of the Eimeria parasite supplied by a vaccine will enable the host organism to develop an innate immune response towards the pathogen. The production of traditional live anticoccidial vaccines is limited by their low reproductive index and high production costs, among other factors. Recombinant vaccines overcome these limitations by eliciting undesired contaminants and prevent the reversal of toxoids back to their original toxigenic form. Recombinant vaccines are produced using defined Eimeria antigens and harmless adjuvants. Thus, studies regarding the identification of potent novel Eimeria antigens which stimulate both cell-mediated and humoral immune responses in chickens are essential. Although the prevalence and risk posed by Eimeria have been well established, there is a dearth of information on genetic and antigenic diversity within the field. Therefore, this paper discusses the potential and efficiency of recombinant vaccines as an anticoccidial control measure. Novel protective Eimeria antigens and their antigenic diversity for the production of cheap, easily accessible recombinant vaccines are also reviewed.
Topics: Adjuvants, Immunologic; Animals; Antigens; Chickens; Coccidiosis; Eimeria; Poultry Diseases; Protozoan Vaccines
PubMed: 31065831
DOI: 10.1007/s00436-019-06338-2 -
Journal of Biomedical Semantics Apr 2024Pathogenic parasites are responsible for multiple diseases, such as malaria and Chagas disease, in humans and livestock. Traditionally, pathogenic parasites have been...
BACKGROUND
Pathogenic parasites are responsible for multiple diseases, such as malaria and Chagas disease, in humans and livestock. Traditionally, pathogenic parasites have been largely an evasive topic for vaccine design, with most successful vaccines only emerging recently. To aid vaccine design, the VIOLIN vaccine knowledgebase has collected vaccines from all sources to serve as a comprehensive vaccine knowledgebase. VIOLIN utilizes the Vaccine Ontology (VO) to standardize the modeling of vaccine data. VO did not model complex life cycles as seen in parasites. With the inclusion of successful parasite vaccines, an update in parasite vaccine modeling was needed.
RESULTS
VIOLIN was expanded to include 258 parasite vaccines against 23 protozoan species, and 607 new parasite vaccine-related terms were added to VO since 2022. The updated VO design for parasite vaccines accounts for parasite life stages and for transmission-blocking vaccines. A total of 356 terms from the Ontology of Parasite Lifecycle (OPL) were imported to VO to help represent the effect of different parasite life stages. A new VO class term, 'transmission-blocking vaccine,' was added to represent vaccines able to block infectious transmission, and one new VO object property, 'blocks transmission of pathogen via vaccine,' was added to link vaccine and pathogen in which the vaccine blocks the transmission of the pathogen. Additionally, our Gene Set Enrichment Analysis (GSEA) of 140 parasite antigens used in the parasitic vaccines identified enriched features. For example, significant patterns, such as signal, plasma membrane, and entry into host, were found in the antigens of the vaccines against two parasite species: Plasmodium falciparum and Toxoplasma gondii. The analysis found 18 out of the 140 parasite antigens involved with the malaria disease process. Moreover, a majority (15 out of 54) of P. falciparum parasite antigens are localized in the cell membrane. T. gondii antigens, in contrast, have a majority (19/24) of their proteins related to signaling pathways. The antigen-enriched patterns align with the life cycle stage patterns identified in our ontological parasite vaccine modeling.
CONCLUSIONS
The updated VO modeling and GSEA analysis capture the influence of the complex parasite life cycles and their associated antigens on vaccine development.
Topics: Biological Ontologies; Animals; Parasites; Protozoan Vaccines; Humans; Vaccines; Models, Biological
PubMed: 38664818
DOI: 10.1186/s13326-024-00307-0 -
Vaccine Jul 2019Since the discovery of Toxoplasma gondii in 1908, it is estimated that one-third of the global population has been exposed to this ubiquitous intracellular protozoan.... (Review)
Review
Since the discovery of Toxoplasma gondii in 1908, it is estimated that one-third of the global population has been exposed to this ubiquitous intracellular protozoan. The complex life cycle of T. gondii has enabled itself to overcome stress and transmit easily within a broad host range thus achieving a high seroprevalence worldwide. To date, toxoplasmosis remains one of the most prevalent HIV-associated opportunistic central nervous system infections. This review presents a comprehensive overview of different vaccination approaches ranging from traditional inactivated whole-T. gondii vaccines to the popular DNA vaccines. Extensive discussions are made to highlight the challenges in constructing these vaccines, selecting adjuvants as well as delivery methods, immunisation approaches and developing study models. Herein we also deliberate over the latest and promising enhancement strategies that can address the limitations in developing an effective T. gondii prophylactic vaccine.
Topics: Animals; Humans; Protozoan Vaccines; Toxoplasma; Toxoplasmosis; Vaccination; Vaccines, DNA
PubMed: 31186188
DOI: 10.1016/j.vaccine.2019.05.083 -
Infection, Genetics and Evolution :... Sep 2007Parasites cause some of the most devastating and prevalent diseases in humans and animals. Moreover, parasitic infections increase mortality rates of other serious... (Review)
Review
Parasites cause some of the most devastating and prevalent diseases in humans and animals. Moreover, parasitic infections increase mortality rates of other serious non-parasitic infections caused by pathogens such as HIV-1. The impact of parasitic diseases in both industrialised and developing countries is further exacerbated by the resistance of some parasites to anti-parasitic drugs and the absence of efficacious parasite vaccines. Despite years of research, much remains to be done to develop effective vaccines against parasites. This review focuses on the more recent vaccine strategies such as DNA and viral vector-based vaccines that are currently being used to develop vaccines against parasites. Obstacles yet to be overcome and possible advantages and disadvantages of these vaccine modalities are also discussed.
Topics: Animals; Humans; Protozoan Infections; Protozoan Vaccines; Vaccines, Synthetic
PubMed: 17702669
DOI: 10.1016/j.meegid.2007.06.004 -
Trends in Biotechnology Nov 1992Antibodies to surface proteins of the sexual stages of Plasmodium falciparum block completely the transmission of these malaria parasites. Transmission-blocking vaccines...
Antibodies to surface proteins of the sexual stages of Plasmodium falciparum block completely the transmission of these malaria parasites. Transmission-blocking vaccines therefore represent a powerful and novel approach to controlling the spread of this lethal disease.
Topics: Animals; Female; Humans; Malaria; Male; Plasmodium falciparum; Protozoan Proteins; Protozoan Vaccines; Yeasts
PubMed: 1368880
DOI: 10.1016/0167-7799(92)90280-9 -
Parasitology Apr 2014Effective vaccines are available for many protozoal diseases of animals, including vaccines for zoonotic pathogens and for several species of vector-transmitted... (Review)
Review
Effective vaccines are available for many protozoal diseases of animals, including vaccines for zoonotic pathogens and for several species of vector-transmitted apicomplexan haemoparasites. In comparison with human diseases, vaccine development for animals has practical advantages such as the ability to perform experiments in the natural host, the option to manufacture some vaccines in vivo, and lower safety requirements. Although it is proper for human vaccines to be held to higher standards, the enduring lack of vaccines for human protozoal diseases is difficult to reconcile with the comparatively immense amount of research funding. Common tactical problems of human protozoal vaccine research include reliance upon adapted rather than natural animal disease models, and an overwhelming emphasis on novel approaches that are usually attempted in replacement of rather than for improvement upon the types of designs used in effective veterinary vaccines. Currently, all effective protozoal vaccines for animals are predicated upon the ability to grow protozoal organisms. Because human protozoal vaccines need to be as effective as animal vaccines, researchers should benefit from a comparison of existing veterinary products and leading experimental vaccine designs. With this in mind, protozoal vaccines are here reviewed.
Topics: Animals; Disease Models, Animal; Humans; Malaria; Protozoan Infections; Protozoan Vaccines; Research Support as Topic; Vaccination; Veterinary Medicine
PubMed: 24476952
DOI: 10.1017/S0031182013002060 -
Archivum Immunologiae Et Therapiae... 2008Leishmaniasis causes significant morbidity and mortality worldwide, constituting an important public health problem. Leishmania infections cause a wide spectrum of... (Review)
Review
Leishmaniasis causes significant morbidity and mortality worldwide, constituting an important public health problem. Leishmania infections cause a wide spectrum of diseases, ranging in severity from spontaneously healing skin lesions to fatal visceral disease. Attempts to develop an effective vaccine to control leishmaniasis have been shown to be feasible, but no vaccine is in active clinical use. The ability to create genetically modified parasites by eliminating virulence or essential genes is considered a powerful alternative in the development of an effective protective vaccine. Here, recent findings related to genetically defined live attenuated Leishmania parasites as promising vaccine candidates are reviewed.
Topics: Animals; Animals, Genetically Modified; Humans; Leishmania; Protozoan Vaccines; Vaccines, Attenuated
PubMed: 18373245
DOI: 10.1007/s00005-008-0010-9 -
Irish Journal of Medical Science Feb 2023Toxoplasma gondii is an obligate intracellular parasite that causes toxoplasmosis. It has been shown that the severity of symptoms depends on the functioning of the host... (Review)
Review
Toxoplasma gondii is an obligate intracellular parasite that causes toxoplasmosis. It has been shown that the severity of symptoms depends on the functioning of the host immune system. Although T. gondii infection typically does not lead to severe disease in healthy people and after infection, it induces a stable immunity, but it can contribute to severe and even lethal Toxoplasmosis in immunocompromised individuals (AIDS, bone marrow transplant and neoplasia). The antigens that have been proposed to be used in vaccine candidate in various studies include surface antigens and secretory excretions that have been synthesized and evaluated in different studies. In some studies, secretory antigens play an important role in stimulating the host immune response. Various antigens such as SAG, GRA, ROP, ROM, and MAG have been from different strains of T. gondii have been synthesized and their protective effects have been evaluated in animal models in different vaccine platforms including recombinant antigens, nanoparticles, and DNA vaccine. Four bibliographic databases including Science Direct, PubMed Central (PMC), Scopus, and Google Scholar were searched for articles published up to 2020.The current review article focuses on recent studies on the use and usefulness of recombinant antigens, nanoparticles, and DNA vaccines.
Topics: Animals; Humans; Mice; Toxoplasma; Antigens, Protozoan; Protozoan Proteins; Protozoan Vaccines; Toxoplasmosis; Vaccines, DNA; Mice, Inbred BALB C
PubMed: 35394635
DOI: 10.1007/s11845-022-02998-9 -
Trends in Parasitology Jul 2010The control of infection by Leishmania infantum (syn. Leishmania chagasi) in dogs is essential to stop the current spread of zoonotic visceral leishmaniasis. The past... (Review)
Review
The control of infection by Leishmania infantum (syn. Leishmania chagasi) in dogs is essential to stop the current spread of zoonotic visceral leishmaniasis. The past few years have seen significant advances in achieving efficient immunization of dogs and, more than ever before, an effective vaccine against canine leishmaniasis can now be considered a feasible goal. This article summarizes experimental data gathered from recent dog trials aimed at identifying immunological mechanisms implicated in protection against canine infection to discuss their potential to serve as quantitative surrogate markers of immunization and, more importantly, its usefulness to evaluate whether the immunity induced by the vaccine candidate is strong enough to protect against canine leishmaniasis.
Topics: Animals; Dog Diseases; Dogs; Leishmania; Leishmaniasis, Visceral; Protozoan Vaccines
PubMed: 20488751
DOI: 10.1016/j.pt.2010.04.005