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Human Vaccines & Immunotherapeutics 2014Cryptosporidium spp is a ubiquitous parasite that has long been recognized as a frequent cause of protozoal diarrhea in humans. While infections in immunocompetent hosts... (Review)
Review
Cryptosporidium spp is a ubiquitous parasite that has long been recognized as a frequent cause of protozoal diarrhea in humans. While infections in immunocompetent hosts are usually self-limiting, immunocompromised individuals can develop severe, chronic, and life-threatening illness. Vaccine development or immunotherapy that prevents disease or reduces the severity of infection is a relevant option since efficacious drug treatments are lacking. In particular, children in developing countries might benefit the most from a vaccine since cryptosporidiosis in early childhood has been reported to be associated with subsequent impairment in growth, physical fitness, and intellectual capacity. In this review, immunotherapies that have been used clinically are described as well as experimental vaccines and their evaluation in vivo.
Topics: Biological Products; Cryptosporidiosis; Cryptosporidium; Global Health; Humans; Immunotherapy; Protozoan Vaccines
PubMed: 24638018
DOI: 10.4161/hv.28485 -
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 -
Frontiers in Immunology 2021Despite mass drug administration programmes with praziquantel, the prevalence of schistosomiasis remains high. A vaccine is urgently needed to control transmission of... (Review)
Review
Despite mass drug administration programmes with praziquantel, the prevalence of schistosomiasis remains high. A vaccine is urgently needed to control transmission of this debilitating disease. As some promising schistosomiasis vaccine candidates are moving through pre-clinical and clinical testing, we review the immunological challenges that these vaccine candidates may encounter in transitioning through the clinical trial phases in endemic settings. Prior exposure of the target population to schistosomes and other infections may impact vaccine response and efficacy and therefore requires considerable attention. Schistosomes are known for their potential to induce T-reg/IL-10 mediated immune suppression in populations which are chronically infected. Moreover, endemicity of schistosomiasis is focal whereby target and trial populations may exhibit several degrees of prior exposure as well as exposure which may increase heterogeneity of vaccine responses. The age dependent distribution of exposure and development of acquired immunity, and general differences in the baseline immunological profile, adds to the complexity of selecting suitable trial populations. Similarly, prior or concurrent infections with other parasitic helminths, viral and bacterial infections, may alter immunological responses. Consequently, treatment of co-infections may benefit the immunogenicity of vaccines and may be considered despite logistical challenges. On the other hand, viral infections leave a life-long immunological imprint on the human host. Screening for serostatus may be needed to facilitate interpretation of vaccine responses. Co-delivery of schistosome vaccines with PZQ is attractive from a perspective of implementation but may complicate the immunogenicity of schistosomiasis vaccines. Several studies have reported PZQ treatment to induce both transient and long-term immuno-modulatory effects as a result of tegument destruction, worm killing and subsequent exposure of worm antigens to the host immune system. These in turn may augment or antagonize vaccine immunogenicity. Understanding the complex immunological interactions between vaccine, co-infections or prior exposure is essential in early stages of clinical development to facilitate phase 3 clinical trial design and implementation policies. Besides well-designed studies in different target populations using schistosome candidate vaccines or other vaccines as models, controlled human infections could also help identify markers of immune protection in populations with different disease and immunological backgrounds.
Topics: Animals; Coinfection; Drug Design; Drug Development; Endemic Diseases; Host-Parasite Interactions; Humans; Immunogenicity, Vaccine; Praziquantel; Protozoan Vaccines; Schistosoma; Schistosomiasis; Schistosomicides
PubMed: 33746974
DOI: 10.3389/fimmu.2021.635985 -
Frontiers in Cellular and Infection... 2018Eukaryotic parasites and pathogens continue to cause some of the most detrimental and difficult to treat diseases (or disease states) in both humans and animals, while... (Review)
Review
Eukaryotic parasites and pathogens continue to cause some of the most detrimental and difficult to treat diseases (or disease states) in both humans and animals, while also continuously expanding into non-endemic countries. Combined with the ever growing number of reports on drug-resistance and the lack of effective treatment programs for many metazoan diseases, the impact that these organisms will have on quality of life remain a global challenge. Vaccination as an effective prophylactic treatment has been demonstrated for well over 200 years for bacterial and viral diseases. From the earliest variolation procedures to the cutting edge technologies employed today, many protective preparations have been successfully developed for use in both medical and veterinary applications. In spite of the successes of these applications in the discovery of subunit vaccines against prokaryotic pathogens, not many targets have been successfully developed into vaccines directed against metazoan parasites. With the current increase in -omics technologies and metadata for eukaryotic parasites, target discovery for vaccine development can be expedited. However, a good understanding of the host/vector/pathogen interface is needed to understand the underlying biological, biochemical and immunological components that will confer a protective response in the host animal. Therefore, systems biology is rapidly coming of age in the pursuit of effective parasite vaccines. Despite the difficulties, a number of approaches have been developed and applied to parasitic helminths and arthropods. This review will focus on key aspects of vaccine development that require attention in the battle against these metazoan parasites, as well as successes in the field of vaccine development for helminthiases and ectoparasites. Lastly, we propose future direction of applying successes in pursuit of next generation vaccines.
Topics: Animals; Antigens, Protozoan; Arthropods; Drug Discovery; Drug Resistance; Helminths; Host-Parasite Interactions; Metadata; Parasites; Parasitic Diseases, Animal; Protozoan Vaccines; Systems Biology; Vaccination
PubMed: 29594064
DOI: 10.3389/fcimb.2018.00067 -
Expert Review of Vaccines Nov 2021Pathogenesis of Chagas disease (CD) caused by involves chronic oxidative and inflammatory stress. In this review, we discuss the research efforts in therapeutic vaccine... (Review)
Review
INTRODUCTION
Pathogenesis of Chagas disease (CD) caused by involves chronic oxidative and inflammatory stress. In this review, we discuss the research efforts in therapeutic vaccine development to date and the potential challenges imposed by oxidative stress in achieving an efficient therapeutic vaccine against CD.
AREAS COVERED
This review covers the immune and nonimmune mechanisms of reactive oxygen species production and immune response patterns during in CD. A discussion on immunotherapy development efforts, the efficacy of antigen-based immune therapies against , and the role of antioxidants as adjuvants is discussed to provide promising insights to developing future treatment strategies against CD.
EXPERT OPINION
Administration of therapeutic vaccines can be a good option to confront persistent parasitemia in CD by achieving a rapid, short-lived stimulation of type 1 cell-mediated immunity. At the same time, adjunct therapies could play a critical role in the preservation of mitochondrial metabolism and cardiac muscle contractility in CD. We propose combined therapy with antigen-based vaccine and small molecules to control the pathological oxidative insult would be effective in the conservation of cardiac structure and function in CD.
Topics: Chagas Disease; Humans; Oxidative Stress; Protozoan Vaccines; Trypanosoma cruzi; Vaccine Development
PubMed: 34406892
DOI: 10.1080/14760584.2021.1969230 -
Infection, Genetics and Evolution :... Nov 2017Eimeria species parasites can cause the disease coccidiosis, most notably in chickens. The occurrence of coccidiosis is currently controlled through a combination of... (Review)
Review
Eimeria species parasites can cause the disease coccidiosis, most notably in chickens. The occurrence of coccidiosis is currently controlled through a combination of good husbandry, chemoprophylaxis and/or live parasite vaccination; however, scalable, cost-effective subunit or recombinant vaccines are required. Many antigens have been proposed for use in novel anticoccidial vaccines, supported by the capacity to reduce disease severity or parasite replication, increase body weight gain in the face of challenge or improve feed conversion under experimental conditions, but none has reached commercial development. Nonetheless, the protection against challenge induced by some antigens has been within the lower range described for the ionophores against susceptible isolates or current live vaccines prior to oocyst recycling. With such levels of efficacy it may be that combinations of anticoccidial antigens already described are sufficient for development as novel multi-valent vaccines, pending identification of optimal delivery systems. Selection of the best antigens to be included in such vaccines can be informed by knowledge defining the natural occurrence of specific antigenic diversity, with relevance to the risk of immediate vaccine breakthrough, and the rate at which parasite genomes can evolve new diversity. For Eimeria, such data are now becoming available for antigens such as apical membrane antigen 1 (AMA1) and immune mapped protein 1 (IMP1) and more are anticipated as high-capacity, high-throughput sequencing technologies become increasingly accessible.
Topics: Animals; Antigenic Variation; Chickens; Coccidia; Coccidiosis; Coccidiostats; Protozoan Vaccines; Vaccines, Synthetic
PubMed: 29017798
DOI: 10.1016/j.meegid.2017.10.009 -
Parasites & Vectors Jul 2015Toxoplasma gondii (T. gondii) is an obligate intracellular protozoan parasite. It has extensive host populations and is prevalent globally; T. gondii infection can cause... (Review)
Review
Toxoplasma gondii (T. gondii) is an obligate intracellular protozoan parasite. It has extensive host populations and is prevalent globally; T. gondii infection can cause a zoonotic parasitic disease. Microneme protein 3 (MIC3) is a secreted protein that is expressed in all stages of the T. gondii life cycle. It has strong immunoreactivity and plays an important role in the recognition, adhesion and invasion of host cells by T. gondii. This article reviews the molecular structure of MIC3, its role in the invasion of host cells by parasites, its relationship with parasite virulence, and its induction of immune protection to lay a solid foundation for an in-depth study of potential diagnostic agents and vaccines for preventing toxoplasmosis.
Topics: Amino Acid Sequence; Animals; Cell Adhesion; Humans; Life Cycle Stages; Molecular Sequence Data; Protozoan Proteins; Protozoan Vaccines; Sequence Alignment; Toxoplasma; Toxoplasmosis, Animal; Vaccines, DNA; Virulence
PubMed: 26194005
DOI: 10.1186/s13071-015-1001-4 -
The Journal of Clinical Investigation Apr 2008Kinetoplastids are a group of flagellated protozoans that include the species Trypanosoma and Leishmania, which are human pathogens with devastating health and economic... (Review)
Review
Kinetoplastids are a group of flagellated protozoans that include the species Trypanosoma and Leishmania, which are human pathogens with devastating health and economic effects. The sequencing of the genomes of some of these species has highlighted their genetic relatedness and underlined differences in the diseases that they cause. As we discuss in this Review, steady progress using a combination of molecular, genetic, immunologic, and clinical approaches has substantially increased understanding of these pathogens and important aspects of the diseases that they cause. Consequently, the paths for developing additional measures to control these "neglected diseases" are becoming increasingly clear, and we believe that the opportunities for developing the drugs, diagnostics, vaccines, and other tools necessary to expand the armamentarium to combat these diseases have never been better.
Topics: Animals; Antiprotozoal Agents; Genetic Vectors; Genome, Protozoan; Humans; Kinetoplastida; Protozoan Infections; Protozoan Vaccines
PubMed: 18382742
DOI: 10.1172/JCI33945 -
Memorias Do Instituto Oswaldo Cruz Mar 2009Toxoplasma gondii has a very wide intermediate host range and is thought to be able to infect all warm blooded animals. The parasite causes a spectrum of different... (Review)
Review
Toxoplasma gondii has a very wide intermediate host range and is thought to be able to infect all warm blooded animals. The parasite causes a spectrum of different diseases and clinical symptoms within the intermediate hosts and following infection most animals develop adaptive humoral and cell-mediated immune responses. The development of protective immunity to T. gondii following natural infection in many host species has led researchers to look at vaccination as a strategy to control disease, parasite multiplication and establishment in animal hosts. A range of different veterinary vaccines are required to help control T. gondii infection which include vaccines to prevent congenital toxoplasmosis, reduce or eliminate tissue cysts in meat producing animals and to prevent oocyst shedding in cats. In this paper we will discuss some of the history, challenges and progress in the development of veterinary vaccines against T. gondii.
Topics: Animals; Antibodies, Protozoan; Host-Parasite Interactions; Protozoan Vaccines; Toxoplasma; Toxoplasmosis, Animal
PubMed: 19430650
DOI: 10.1590/s0074-02762009000200018 -
Experimental Parasitology Sep 2020Despite decades of investigation to clarify protective mechanisms of anticoccidial responses, one crucial field is neglected, that is, protective memory responses in... (Review)
Review
Despite decades of investigation to clarify protective mechanisms of anticoccidial responses, one crucial field is neglected, that is, protective memory responses in primed birds. Protective memory immunity is critical for host resistance to reinfection and is the basis of modern vaccinology, especially in developing successful subunit vaccines. There are important differences between the immune responses induced by infections and antigens delivered either as killed, recombinant proteins or as live, replicating vector vaccines or as DNA vaccines. Animals immunized with these vaccines may fail to develop protective memory immunity, and is still naïve to Eimeria infection. This may explain why limited success is achieved in developing next-generation anticoccidial vaccines. In this review, we try to decipher the protective memory responses against Eimeria infection, assess immune responses elicited by various anticoccidial vaccine candidates, and propose possible approaches to develop rational vaccines that can induce a protective memory response to chicken coccidiosis.
Topics: Animals; Chickens; Coccidiosis; Eimeria; Immunologic Memory; Intestines; Poultry Diseases; Protozoan Vaccines; Recurrence; Vaccination; Vaccines, Subunit
PubMed: 32615133
DOI: 10.1016/j.exppara.2020.107945