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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 -
Expert Review of Vaccines 2024
Topics: Humans; Malaria Vaccines; Malaria, Falciparum; Plasmodium falciparum; Antibodies, Protozoan; Protozoan Proteins
PubMed: 38095048
DOI: 10.1080/14760584.2023.2292204 -
Frontiers in Immunology 2022Malaria is one of the most devastating human infectious diseases caused by spp. parasites. A search for an effective and safe vaccine is the main challenge for its... (Review)
Review
Malaria is one of the most devastating human infectious diseases caused by spp. parasites. A search for an effective and safe vaccine is the main challenge for its eradication. is the second most prevalent species and the most geographically distributed parasite and has been neglected for decades. This has a massive gap in knowledge and consequently in the development of vaccines. The most significant difficulties in obtaining a vaccine against are the high genetic diversity and the extremely complex life cycle. Due to its complexity, studies have evaluated antigens from different stages as potential targets for an effective vaccine. Therefore, the main vaccine candidates are grouped into preerythrocytic stage vaccines, blood-stage vaccines, and transmission-blocking vaccines. This review aims to support future investigations by presenting the main findings of vivax malaria vaccines to date. There are only a few vaccines in clinical trials, and thus far, the best protective efficacy was a vaccine formulated with synthetic peptide from a circumsporozoite protein and Montanide ISA-51 as an adjuvant with 54.5% efficacy in a phase IIa study. In addition, the majority of antigen candidates are polymorphic, induce strain-specific and heterogeneous immunity and provide only partial protection. Nevertheless, immunization with recombinant proteins and multiantigen vaccines have shown promising results and have emerged as excellent strategies. However, more studies are necessary to assess the ideal vaccine combination and test it in clinical trials. Developing a safe and effective vaccine against vivax malaria is essential for controlling and eliminating the disease. Therefore, it is necessary to determine what is already known to propose and identify new candidates.
Topics: Humans; Plasmodium vivax; Antigens, Protozoan; Malaria, Vivax; Malaria; Malaria Vaccines; Clinical Trials, Phase II as Topic
PubMed: 36726991
DOI: 10.3389/fimmu.2022.910236 -
Frontiers in Immunology 2019Malaria remains a serious threat to global health. Sustained malaria control and, eventually, eradication will only be achieved with a broadly effective malaria vaccine.... (Review)
Review
Malaria remains a serious threat to global health. Sustained malaria control and, eventually, eradication will only be achieved with a broadly effective malaria vaccine. Yet a fundamental lack of knowledge about how antimalarial immunity is acquired has hindered vaccine development efforts to date. Understanding how malaria-causing parasites modulate the host immune system, specifically dendritic cells (DCs), key initiators of adaptive and vaccine antigen-based immune responses, is vital for effective vaccine design. This review comprehensively summarizes how exposure to spp. impacts human DC function and . We have highlighted the heterogeneity of the data observed in these studies, compared and critiqued the models used to generate our current understanding of DC function in malaria, and examined the mechanisms by which spp. mediate these effects. This review highlights potential research directions which could lead to improved efficacy of existing vaccines, and outlines novel targets for next-generation vaccine strategies to target malaria.
Topics: Antigens, Protozoan; Dendritic Cells; Humans; Malaria; Malaria Vaccines; Plasmodium
PubMed: 30886619
DOI: 10.3389/fimmu.2019.00357 -
Vaccine Dec 2015Recombinant subunit vaccines in general are poor immunogens likely due to the small size of peptides and proteins, combined with the lack or reduced presentation of... (Review)
Review
Recombinant subunit vaccines in general are poor immunogens likely due to the small size of peptides and proteins, combined with the lack or reduced presentation of repetitive motifs and missing complementary signal(s) for optimal triggering of the immune response. Therefore, recombinant subunit vaccines require enhancement by vaccine delivery vehicles in order to attain adequate protective immunity. Particle-based delivery platforms, including particulate antigens and particulate adjuvants, are promising delivery vehicles for modifying the way in which immunogens are presented to both the innate and adaptive immune systems. These particle delivery platforms can also co-deliver non-specific immunostimodulators as additional adjuvants. This paper reviews efforts and advances of the Particle-based delivery platforms in development of vaccines against malaria, a disease that claims over 600,000 lives per year, most of them are children under 5 years of age in sub-Sahara Africa.
Topics: Adjuvants, Immunologic; Antigens, Protozoan; Humans; Malaria Vaccines; Nanoparticles; Vaccines, Subunit; Vaccines, Virus-Like Particle
PubMed: 26458803
DOI: 10.1016/j.vaccine.2015.09.097 -
Frontiers in Immunology 2021Schistosome infection is a major cause of global morbidity, particularly in sub-Saharan Africa. However, there is no effective vaccine for this major neglected tropical... (Review)
Review
Schistosome infection is a major cause of global morbidity, particularly in sub-Saharan Africa. However, there is no effective vaccine for this major neglected tropical disease, and re-infection routinely occurs after chemotherapeutic treatment. Following invasion through the skin, larval schistosomula enter the circulatory system and migrate through the lung before maturing to adulthood in the mesenteric or urogenital vasculature. Eggs released from adult worms can become trapped in various tissues, with resultant inflammatory responses leading to hepato-splenic, intestinal, or urogenital disease - processes that have been extensively studied in recent years. In contrast, although lung pathology can occur in both the acute and chronic phases of schistosomiasis, the mechanisms underlying pulmonary disease are particularly poorly understood. In chronic infection, egg-mediated fibrosis and vascular destruction can lead to the formation of portosystemic shunts through which eggs can embolise to the lungs, where they can trigger granulomatous disease. Acute schistosomiasis, or Katayama syndrome, which is primarily evident in non-endemic individuals, occurs during pulmonary larval migration, maturation, and initial egg-production, often involving fever and a cough with an accompanying immune cell infiltrate into the lung. Importantly, lung migrating larvae are not just a cause of inflammation and pathology but are a key target for future vaccine design. However, vaccine efforts are hindered by a limited understanding of what constitutes a protective immune response to larvae. In this review, we explore the current understanding of pulmonary immune responses and inflammatory pathology in schistosomiasis, highlighting important unanswered questions and areas for future research.
Topics: Animals; Disease Models, Animal; Host-Parasite Interactions; Humans; Immune Evasion; Lung; Lung Diseases, Parasitic; Mice; Protozoan Vaccines; Schistosoma; Schistosomiasis; Schistosomicides
PubMed: 33953712
DOI: 10.3389/fimmu.2021.635513 -
Frontiers in Immunology 2020Congenital toxoplasmosis has a high impact on human disease worldwide, inducing serious consequences from fetus to adulthood. Despite this, there are currently no human... (Review)
Review
Congenital toxoplasmosis has a high impact on human disease worldwide, inducing serious consequences from fetus to adulthood. Despite this, there are currently no human vaccines available to prevent this infection. Most vaccination studies against infection used animal models in which the infection was established by exogenous inoculation. Here, we review recent research on potential vaccines using animal models in which infection was congenitally established. Endeavors in this field have so far revealed that live or subunit vaccines previously found to confer protection against extrinsically established infections can also protect, at least partially, from vertically transmitted infection. Nevertheless, there is no consensus on the more adequate immune response to protect the host and the fetus in congenital infection. Most of the vaccination studies rely on the assessment of maternal systemic immune responses, quantification of parasitic loads in the fetuses, and survival indexes and/or brain parasitic burden in the neonates. More research must be carried out not only to explore new vaccines but also to further study the nature of the elicited immune protection at the maternal-fetal interface. Particularly, the cellular and molecular effector mechanisms at the maternal-fetal interface induced by immunization remain poorly characterized. Deeper knowledge on the immune response at this specific location will certainly help to refine the vaccine-induced immunity and, consequently, to provide the most effective and safest protection against vertical infection.
Topics: Animals; Antibodies, Protozoan; Humans; Infectious Disease Transmission, Vertical; Protozoan Proteins; Protozoan Vaccines; Toxoplasma; Toxoplasmosis, Congenital
PubMed: 33658997
DOI: 10.3389/fimmu.2020.621997 -
Biomedicine & Pharmacotherapy =... May 2021Human filarial infections are vector-borne nematode infections, which include lymphatic filariasis, onchocerciasis, loiasis, and mansonella filariasis. With a high... (Review)
Review
Human filarial infections are vector-borne nematode infections, which include lymphatic filariasis, onchocerciasis, loiasis, and mansonella filariasis. With a high prevalence in developing countries, filarial infections are responsible for some of the most debilitating morbidities and a vicious cycle of poverty and disease. Global initiatives set to eradicate these infections include community mass treatments, vector control, provision of care for morbidity, and search for vaccines. However, there are growing challenges associated with mass treatments, vector control, and antifilarial vaccine development. With the emergence of genome editing tools and successful applications in other infectious diseases, the integration of genetic editing techniques in future control strategies for filarial infections would offer the best option for eliminating filarial infections. In this review, we briefly discuss the mechanisms of the three main genetic editing techniques and explore the potential applications of these powerful tools to control filarial infections.
Topics: Animals; CRISPR-Associated Protein 9; CRISPR-Cas Systems; Clustered Regularly Interspaced Short Palindromic Repeats; Filariasis; Filaricides; Filarioidea; Gene Editing; Genetic Therapy; Humans; Protozoan Vaccines
PubMed: 33581654
DOI: 10.1016/j.biopha.2021.111292 -
Parasites & Vectors Feb 2015Chagas disease is a zoonosis caused by Trypanosoma cruzi in which the most affected organ is the heart. Conventional chemotherapy has a very low effectiveness; despite... (Review)
Review
Chagas disease is a zoonosis caused by Trypanosoma cruzi in which the most affected organ is the heart. Conventional chemotherapy has a very low effectiveness; despite recent efforts, there is currently no better or more effective treatment available. DNA vaccines provide a new alternative for both prevention and treatment of a variety of infectious disorders, including Chagas disease. Recombinant DNA technology has allowed some vaccines to be developed using recombinant proteins or virus-like particles capable of inducing both a humoral and cellular specific immune response. This type of immunization has been successfully used in preclinical studies and there are diverse models for viral, bacterial and/or parasitic diseases, allergies, tumors and other diseases. Therefore, several research groups have been given the task of designing a DNA vaccine against experimental infection with T. cruzi. In this review we explain what DNA vaccines are and the most recent studies that have been done to develop them with prophylactic or therapeutic purposes against Chagas disease.
Topics: Animals; Chagas Disease; Drug Discovery; Humans; Protozoan Vaccines; Vaccination; Vaccines, DNA
PubMed: 25885641
DOI: 10.1186/s13071-015-0738-0 -
Revista Do Instituto de Medicina... 2021Malaria represents a serious public health problem, presenting with high rates of incidence, morbidity and mortality in tropical and subtropical regions of the world.... (Review)
Review
Malaria represents a serious public health problem, presenting with high rates of incidence, morbidity and mortality in tropical and subtropical regions of the world. According to the World Health Organization, in 2018 there were 228 million cases and 405 thousand deaths caused by this disease in the world, affecting mainly children and pregnant women in Africa. Despite the programs carried out to control this disease, drug resistance and invertebrate vector resistance to insecticides have generated difficulties. An efficient vaccine against malaria would be a strategy with a high impact on the eradication and control of this disease. Researches aimed at developing vaccines have focused on antigens of high importance for the survival of the parasite such as the Circumsporozoite Surface Protein, involved in the pre-erythrocytic cycle during parasites invasion in hepatocytes. Currently, RTS'S is the most promising vaccine for malaria and was constructed using CSP; its performance was evaluated using two types of adjuvants: AS01 and AS02. The purpose of this review was to provide a bibliographic survey of historical researches that led to the development of RTS'S and its performance analysis over the decade. The search for new adjuvants to be associated with this antigen seems to be a way to obtain higher percentages of protection for a future malaria vaccine.
Topics: Humans; Malaria; Malaria Vaccines; Membrane Proteins; Plasmodium falciparum; Protozoan Proteins
PubMed: 33533814
DOI: 10.1590/S1678-9946202163011