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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 -
Infection and Immunity Apr 2020Efficient delivery of antigenic cargo to trigger protective immune responses is critical to the success of vaccination. Genetically engineered microorganisms, including... (Review)
Review
Efficient delivery of antigenic cargo to trigger protective immune responses is critical to the success of vaccination. Genetically engineered microorganisms, including virus, bacteria, and protozoa, can be modified to carry and deliver heterologous antigens to the host immune system. The biological vectors can induce a broad range of immune responses and enhance heterologous antigen-specific immunological outcomes. The protozoan genus is widespread in domestic animals, causing serious coccidiosis. parasites with strong immunogenicity are potent coccidiosis vaccine candidates and offer a valuable model of live vaccines against infectious diseases in animals. parasites can also function as a vaccine vector. Herein, we review recent advances in design and application of recombinant as a vaccine vector, which has been a topic of ongoing research in our laboratory. By recapitulating the establishment of an transfection platform and its application, it will help lay the foundation for the future development of effective parasite-based vaccine delivery vectors and beyond.
Topics: Animals; Antigens, Protozoan; Coccidiosis; Eimeria; Humans; Microorganisms, Genetically-Modified; Protozoan Vaccines; Vaccination; Vaccines, Attenuated; Vaccines, Synthetic
PubMed: 32094255
DOI: 10.1128/IAI.00861-19 -
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 -
The Korean Journal of Parasitology Dec 2014Toxoplasmosis is an opportunistic infection caused by the protozoan parasite Toxoplasma gondii. T. gondii is widespread globally and causes severe diseases in... (Review)
Review
Toxoplasmosis is an opportunistic infection caused by the protozoan parasite Toxoplasma gondii. T. gondii is widespread globally and causes severe diseases in individuals with impaired immune defences as well as congenitally infected infants. The high prevalence rate in some parts of the world such as South America and Africa, coupled with the current drug treatments that trigger hypersensitivity reactions, makes the development of immunotherapeutics intervention a highly important research priority. Immunotherapeutics strategies could either be a vaccine which would confer a pre-emptive immunity to infection, or passive immunization in cases of disease recrudescence or recurrent clinical diseases. As the severity of clinical manifestations is often greater in developing nations, the development of well-tolerated and safe immunotherapeutics becomes not only a scientific pursuit, but a humanitarian enterprise. In the last few years, much progress has been made in vaccine research with new antigens, novel adjuvants, and innovative vaccine delivery such as nanoparticles and antigen encapsulations. A literature search over the past 5 years showed that most experimental studies were focused on DNA vaccination at 52%, followed by protein vaccination which formed 36% of the studies, live attenuated vaccinations at 9%, and heterologous vaccination at 3%; while there were few on passive immunization. Recent progress in studies on vaccination, passive immunization, as well as insights gained from these immunotherapeutics is highlighted in this review.
Topics: Drug Discovery; Global Health; Humans; Immunization; Immunotherapy; Protozoan Vaccines; Toxoplasma; Toxoplasmosis
PubMed: 25548409
DOI: 10.3347/kjp.2014.52.6.581 -
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 -
Frontiers in Immunology 2023, a specialized intracellular parasite, causes a widespread zoonotic disease and is a severe threat to social and economic development. There is a lack of effective...
, a specialized intracellular parasite, causes a widespread zoonotic disease and is a severe threat to social and economic development. There is a lack of effective drugs and vaccines against infection. Recently, mRNA vaccines have been rapidly developed, and their packaging materials and technologies are well established. In this study, TGGT1_216200 (TG_200), a novel molecule from , was identified using bioinformatic screening analysis. TG_200 was purified and encapsulated with a lipid nanoparticle (LNP) to produce the TG_200 mRNA-LNP vaccine. The immune protection provided by the new vaccine and its mechanisms after immunizing BABL/C mice intramuscular injection were investigated. There was a strong immune response when mice were vaccinated with TG_200 mRNA-LNP. Elevated levels of anti--specific immunoglobulin G (IgG), and a higher IgG2a-to-IgG1 ratio was observed. The levels of interleukin-12 (IL-12), interferon-γ (IFN-γ), IL-4, and IL-10 were also elevated. The result showed that the vaccine induced a mixture of Th1 and Th2 cells, and Th1-dominated humoral immune response. Significantly increased antigen-specific splenocyte proliferation was induced by TG_200 mRNA-LNP immunization. The vaccine could also induce -specific cytotoxic T lymphocytes (CTLs). The expression levels of interferon regulatory factor 8 (IRF8), T-Box 21 (T-bet), and nuclear factor kappa B (NF-κB) were significantly elevated after TG_200 mRNA-LNP immunization. The levels of CD83, CD86, MHC-I, MHC-II, CD8, and CD4 molecules were also higher. The results indicated that TG_200 mRNA-LNP produced specific cellular and humoral immune responses. Most importantly, TG_200 mRNA-LNP immunized mice survived significantly longer (19.27 ± 3.438 days) than the control mice, which died within eight days after challenge ( 0.001). The protective effect of adoptive transfer was also assessed, and mice receiving serum and splenocytes from mice immunized with TG_200 mRNA-LNP showed improved survival rates of 9.70 ± 1.64 days and, 13.40 ± 2.32 days, respectively ( 0.001). The results suggested that TG_200 mRNA-LNP is a safe and promising vaccine against infection.
Topics: Animals; Mice; Mice, Inbred BALB C; Protozoan Proteins; Protozoan Vaccines; Toxoplasmosis; Immunization; Immunoglobulin G
PubMed: 37122740
DOI: 10.3389/fimmu.2023.1161507 -
Revue Scientifique Et Technique... Sep 1990The fundamental principles of genetic manipulation are explained, as are the methods of production of vaccines of veterinary importance. Specific attenuation of... (Review)
Review
The fundamental principles of genetic manipulation are explained, as are the methods of production of vaccines of veterinary importance. Specific attenuation of micro-organisms may result from genetically-engineered mutations which produce metabolic blocks, from the development of effective bacterial toxoids and from viral gene segment reassortment. Recombinant DNA techniques have been used to produce multi-component vaccines by the insertion of genes into carrier organisms, such as pox viruses and attenuated salmonella, and also to produce subunit vaccines. The use of synthetic peptide vaccines and anti-idiotype vaccines, together with problems of parasite vaccines, are described. Biotechnology would appear to have a major role to play in the future prevention of many animal diseases.
Topics: Adjuvants, Immunologic; Animals; Bacterial Vaccines; Base Sequence; DNA, Bacterial; Molecular Sequence Data; Protozoan Vaccines; Vaccines, Synthetic; Viral Vaccines
PubMed: 2132704
DOI: 10.20506/rst.9.3.523 -
The Israel Medical Association Journal... Oct 2009There is still a need for innovative and alternative therapies against leishmaniasis. Despite recent advances in immunology, effective immunotherapy against the disease... (Review)
Review
There is still a need for innovative and alternative therapies against leishmaniasis. Despite recent advances in immunology, effective immunotherapy against the disease has not yet been proven. Live, attenuated and dead parasites, purified and recombinant specific antigens, DNA vaccines as well as DC-based immunization that have been employed in the development of protective vaccine have not yet been adopted as immunotherapeutic agents. Recently, a commercially prophylactic vaccine (Leish-110f) was developed by BioPharm International, by constructing a recombinant fusion protein consisting of TSA (thiol-specific antioxidant), LmSTI1 (L. major stress-inducible protein 1) and LeIF (Leishmania elongation initiation factor). This vaccine, when administered together with the adjuvant monophosphoryl lipid A (MPL), either alone or plus squalene (MPL-SE) or AdjuPrime, protected mice against L. major and L. infantum infections. Also, Leishvacin (Leishvacin, Biobrs, Montes Carlos, State of Minas Gerais, Brazil), a commercial non-living promastigote polyvalent Leishmania vaccine administered either alone or combined with BCG, was found to be highly immunogenic against American CL in humans. Leishvacin alone was also found to be effective as a prophylactic vaccine, sensitizing lymphocytes from normal uninfected humans, which was further accelerated by recombinant GM-CSF. Standardization and additional carefully controlled studies in animals and humans, using these new vaccines and other immunomodulators in conjunction with various chemotherapeutic agents, are still required to determine the optimal conditions for the development of a potent anti-leishmanial immunotherapy and immunochemotherapy.
Topics: Animals; Antiprotozoal Agents; Humans; Immunotherapy; Leishmania; Leishmaniasis; Protozoan Vaccines
PubMed: 20077951
DOI: No ID Found -
Clinical Microbiology Reviews Apr 2001Leishmaniae are obligatory intracellular protozoa in mononuclear phagocytes. They cause a spectrum of diseases, ranging in severity from spontaneously healing skin... (Review)
Review
Leishmaniae are obligatory intracellular protozoa in mononuclear phagocytes. They cause a spectrum of diseases, ranging in severity from spontaneously healing skin lesions to fatal visceral disease. Worldwide, there are 2 million new cases each year and 1/10 of the world's population is at risk of infection. To date, there are no vaccines against leishmaniasis and control measures rely on chemotherapy to alleviate disease and on vector control to reduce transmission. However, a major vaccine development program aimed initially at cutaneous leishmaniasis is under way. Studies in animal models and humans are evaluating the potential of genetically modified live attenuated vaccines, as well as a variety of recombinant antigens or the DNA encoding them. The program also focuses on new adjuvants, including cytokines, and delivery systems to target the T helper type 1 immune responses required for the elimination of this intracellular organism. The availability, in the near future, of the DNA sequences of the human and Leishmania genomes will extend the vaccine program. New vaccine candidates such as parasite virulence factors will be identified. Host susceptibility genes will be mapped to allow the vaccine to be targeted to the population most in need of protection.
Topics: Animals; History, 20th Century; Humans; Leishmania; Leishmaniasis; Protozoan Vaccines
PubMed: 11292637
DOI: 10.1128/CMR.14.2.229-243.2001 -
Human Vaccines & Immunotherapeutics 2014Entamoeba histolytica is the causative agent of amebiasis, one of the top three parasitic causes of mortality worldwide. In the majority of infected individuals, E.... (Review)
Review
Entamoeba histolytica is the causative agent of amebiasis, one of the top three parasitic causes of mortality worldwide. In the majority of infected individuals, E. histolytica asymptomatically colonizes the large intestine, while in others, the parasite breaches the mucosal epithelial barrier to cause amebic colitis and can disseminate to soft organs to cause abscesses. Vaccinations using native and recombinant forms of the parasite Gal-lectin have been successful in protecting animals against intestinal amebiasis and amebic liver abscess. Protection against amebic liver abscesses has also been reported by targeting other E. histolytica components including the serine-rich protein and the 29-kDa-reductase antigen. To date, vaccines against the Gal-lectin hold the most promise but clinical trials will be required to validate its efficacy in humans. Here, we review the current strategies and future perspectives involved in the development of a vaccine against E. histolytica.
Topics: Animals; Disease Models, Animal; Drug Discovery; Entamoeba histolytica; Entamoebiasis; Humans; Protozoan Vaccines
PubMed: 24504133
DOI: 10.4161/hv.27796