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Methods in Molecular Biology (Clifton,... 2021Vaccination was developed by Edward Jenner in 1796. Since then, vaccination and vaccine development research has been a hotspot of research in the scientific community....
Vaccination was developed by Edward Jenner in 1796. Since then, vaccination and vaccine development research has been a hotspot of research in the scientific community. Various ways of vaccine development are successfully employed in mass production of vaccines. One of the most successful ways to generate vaccines is the method of virulence attenuation in pathogens. The attenuated strains of viruses, bacteria, and parasites are used as vaccines which elicit robust immune response and confers protection against virulent pathogens. This chapter brings together the most common and efficient ways of generating live attenuated vaccine strains in viruses, bacteria, and parasites.
Topics: Animals; Bacterial Vaccines; Cell Line; Codon Usage; Female; Gamma Rays; Gene Silencing; Humans; Immunization; Immunogenicity, Vaccine; Influenza A virus; Mice; MicroRNAs; Models, Animal; Mutagenesis; Orthomyxoviridae Infections; Protozoan Vaccines; Radiation, Ionizing; Vaccines, Attenuated; Vaccinology; Virulence
PubMed: 32959252
DOI: 10.1007/978-1-0716-0795-4_17 -
Trends in Parasitology Apr 2022The control of diseases caused by protozoan parasites is one of the United Nations' Sustainable Development Goals. In recent years much research effort has gone into... (Review)
Review
The control of diseases caused by protozoan parasites is one of the United Nations' Sustainable Development Goals. In recent years much research effort has gone into developing a new generation of live attenuated vaccines (LAVs) against malaria, Chagas disease and leishmaniasis. However, there is a bottleneck related to their biosafety, production, and distribution that slows downs further development. The success of irradiated or genetically attenuated sporozoites against malaria, added to the first LAV against leishmaniasis to be evaluated in clinical trials, is indicative that the drawbacks of LAVs are gradually being overcome. However, whether persistence of LAVs is a prerequisite for sustained long-term immunity remains to be clarified, and the procedures necessary for clinical evaluation of vaccine candidates need to be standardized.
Topics: Animals; Antigens, Protozoan; Leishmaniasis; Malaria; Malaria Vaccines; Protozoan Vaccines; Sporozoites; Vaccines, Attenuated
PubMed: 34896016
DOI: 10.1016/j.pt.2021.11.004 -
PLoS Pathogens Sep 2018
Review
Topics: Animals; Diarrhea; Giardia lamblia; Giardiasis; Humans; Protozoan Vaccines; Vacuoles
PubMed: 30261050
DOI: 10.1371/journal.ppat.1007250 -
Annals of Tropical Medicine and... Dec 1995Unlike some other parasites, Leishmania can be grown in cell-free media with ease. This simple cultivation and the use of killed parasites as skin-test antigens... (Review)
Review
Unlike some other parasites, Leishmania can be grown in cell-free media with ease. This simple cultivation and the use of killed parasites as skin-test antigens (leishmanin) for diagnosis in humans during the past several decades have prompted scientists to try using the killed parasites, with or without adjuvant, as vaccines or for immunotherapy. In addition, different recombinant molecules, either parasite fractions or genetically engineered organisms (i.e. Leishmania made avirulent by removing specific genes, or bacteria carrying and expressing leishmanial genes), are being investigated as potential future vaccines against leishmaniasis. The 'first-generation' vaccines, composed of killed parasites with or without adjuvant, have been derived using an empirical approach. The 'second-generation' vaccines have been genetically constructed, using a more rational approach. At present, the first-generation vaccines are at various stages of Phase I (safety), II (reactivity) or III (efficacy) trials in humans. Results are expected in 1-2 years. The second-generation vaccines are, however, only in a preclinical state and are not expected to reach clinical trials for at least 3 years. The Special Programme for Research and Training in Tropical Diseases (TDR) is actively involved in most clinical trials of the first-generation vaccines and supports many of the second-generation candidates. In the present article, the advantages and disadvantages of each approach to vaccine development are discussed and the progress being made is briefly reviewed.
Topics: Animals; BCG Vaccine; Combined Modality Therapy; Dogs; Humans; Leishmania; Leishmaniasis; Mice; Protozoan Vaccines; Vaccines, Attenuated; Vaccines, Inactivated; Vaccines, Synthetic
PubMed: 8745930
DOI: 10.1080/00034983.1995.11813017 -
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 -
The Lancet. Infectious Diseases Jan 2015Cryptosporidium spp are well recognised as causes of diarrhoeal disease during waterborne epidemics and in immunocompromised hosts. Studies have also drawn attention to... (Review)
Review
Cryptosporidium spp are well recognised as causes of diarrhoeal disease during waterborne epidemics and in immunocompromised hosts. Studies have also drawn attention to an underestimated global burden and suggest major gaps in optimum diagnosis, treatment, and immunisation. Cryptosporidiosis is increasingly identified as an important cause of morbidity and mortality worldwide. Studies in low-resource settings and high-income countries have confirmed the importance of cryptosporidium as a cause of diarrhoea and childhood malnutrition. Diagnostic tests for cryptosporidium infection are suboptimum, necessitating specialised tests that are often insensitive. Antigen-detection and PCR improve sensitivity, and multiplexed antigen detection and molecular assays are underused. Therapy has some effect in healthy hosts and no proven efficacy in patients with AIDS. Use of cryptosporidium genomes has helped to identify promising therapeutic targets, and drugs are in development, but methods to assess the efficacy in vitro and in animals are not well standardised. Partial immunity after exposure suggests the potential for successful vaccines, and several are in development; however, surrogates of protection are not well defined. Improved methods for propagation and genetic manipulation of the organism would be significant advances.
Topics: Antiprotozoal Agents; Cryptosporidiosis; Diagnostic Tests, Routine; Diarrhea; Global Health; Humans; Protozoan Vaccines
PubMed: 25278220
DOI: 10.1016/S1473-3099(14)70772-8 -
Veterinary Parasitology Jul 2001Over the last decade, the anti-parasitics market has been the fastest growing sector of the overall $18 billion animal health market. While drugs for the treatment of... (Review)
Review
Over the last decade, the anti-parasitics market has been the fastest growing sector of the overall $18 billion animal health market. While drugs for the treatment of parasites of livestock still dominate this sector and will continue to be developed or re-formulated, because of consumer demands for chemical-free food and of concerns regarding the environment and animal welfare there is a growing interest in the development of safe and effective vaccines. There is also a call for vaccines in the lucrative $3 billion-plus companion animal market. These demands for vaccines will add a greater impetus to an area that has seen tremendous success in the last 15 years. A number of anti-parasite vaccines have been developed, e.g. the recombinant 45w and EG95 oncosphere proteins against Taenia ovis and Echinococcus granulosis, respectively, and the Bm86 vaccine against Boophilus microplus. In addition, the cathepsin L vaccines against the liver fluke, Fasciola hepatica, and the H11 vaccine against Haemonchus contortus are progressing well. There are also many additional vaccine candidates for H. contortus and for other nematodes such as Ostertagia and Trichostrongylus spp. that may ultimately lead to broad-spectrum gastrointestinal worm vaccines. Live or attenuated-live vaccines are available for the control of avian coccidiosis, toxplasmosis in sheep and anaplasmosis in cattle, although molecular vaccines against protozoans are still proving elusive. The wealth of information in genomics, proteomics and immunology that has been forthcoming together will new methods of vaccine production and delivery should see many new vaccines reach the marketplace in the near future.
Topics: Animals; Animals, Domestic; Cathepsin L; Cathepsins; Cysteine Endopeptidases; Parasitic Diseases, Animal; Protozoan Vaccines; Vaccination; Vaccines, Inactivated
PubMed: 11516584
DOI: 10.1016/s0304-4017(01)00430-7 -
FEBS Letters May 2006In the past decades, a gradual increase in the resistance to antibiotics has been observed, leading to a serious thread for successful treatment of bacterial infections.... (Review)
Review
In the past decades, a gradual increase in the resistance to antibiotics has been observed, leading to a serious thread for successful treatment of bacterial infections. This feature in addition to difficulties in developing adequate drugs against (tropical) diseases caused by parasites has stimulated the interest in vaccines to prevent infections. In principle, various types of cell surface epitopes, characteristic for the invading organism or related to aberrant growth of cells, can be applied to develop vaccines. The progress in establishing the structure of carbohydrate immuno-determinants in conjunction with improvements in carbohydrate synthesis has rendered it feasible to develop new generations of carbohydrate-based vaccines.
Topics: Animals; Antigens, Surface; Bacterial Vaccines; Cancer Vaccines; Carbohydrates; Feasibility Studies; Glycoconjugates; Protozoan Vaccines
PubMed: 16630616
DOI: 10.1016/j.febslet.2006.03.053 -
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 -
Expert Review of Vaccines Nov 2013Toxoplasmosis caused by the protozoan Toxoplasma gondii is a major public health problem, infecting one-third of the world human beings, and leads to abortion in... (Review)
Review
Toxoplasmosis caused by the protozoan Toxoplasma gondii is a major public health problem, infecting one-third of the world human beings, and leads to abortion in domestic animals. A vaccine strategy would be an ideal tool for improving disease control. Many efforts have been made to develop vaccines against T. gondii to reduce oocyst shedding in cats and tissue cyst formation in mammals over the last 20 years, but only a live-attenuated vaccine based on the S48 strain has been licensed for veterinary use. Here, the authors review the recent development of T. gondii vaccines in cats, food-producing animals and mice, and present its future perspectives. However, a single or only a few antigen candidates revealed by various experimental studies are limited by only eliciting partial protective immunity against T. gondii. Future studies of T. gondii vaccines should include as many CTL epitopes as the live attenuated vaccines.
Topics: Animals; Animals, Domestic; Cat Diseases; Cats; Drug Discovery; Humans; Protozoan Vaccines; Toxoplasma; Toxoplasmosis; Toxoplasmosis, Animal
PubMed: 24093877
DOI: 10.1586/14760584.2013.844652