Patent Landscape of Helminth Vaccines and Related Technologies

Executive Summary This report focuses on patent landscape analysis of technologies related to vaccines targeting parasitic worms, also known as helminths. These technologies include methods of formulating vaccines, methods of producing of subunits, the composition of complete vaccines, and other technologies that have the potential to aid in a global response to this pathogen. The purpose of this patent landscape study was to search, identify, and categorize patent documents that are relevant to the development of vaccines that can efficiently promote the development of protective immunity against helminths. The search strategy used keywords which the team felt would be general enough to capture (or “recall”) the majority of patent documents which were directed toward vaccines against helminths. After extensive searching of patent literature databases, approximately 2847 publications were identified and collapsed to about 446 INPADOC families. Relevant patent families, almost half of the total relevant families (210 being total number of relevant families), were then identified and sorted into the categories of trematodes, cestodes, nematodes or nonspecific helminth. The 210 patent families that were divided into these four major categories were then further divided into sub categories relating to common fields of technology (e.g. DNA vaccine, vaccine formulations, methods to produce subunits) This sorting process increased the precision of the result set. The four major categories (cestodes, nematodes, trematodes, and non specific applications) as well as the overall data set of the 210 relevant family members were subjected to a range of analytics in order to extract as much information as possible from the dataset. First, patent landscape maps were generated to assess the accuracy of the sorting procedure and to reveal the relationships between the various technologies that are involved in creating an effective vaccine. Then, filings trends are analyzed for the overall dataset of the 210 relevant families as well as by the categories of trematodes, cestodes, and nematodes. The country of origin each member of the 210 relevant families was determined, and the range of distribution to other jurisdictions was assessed. Filings were also analyzed by year, by assignee. Finally, the various patent classification systems were mapped to find which particular classes tend to hold helminth vaccine-related technologies. Besides the keywords developed during the searches and the landscape map generation, the classifications represent an alternate way for further researchers to identify emerging helminth vaccine technologies. The analysis included creation of a map of keywords describing the relationship of the various technologies involved in the development of helminth vaccines. The map has regions corresponding to plasmids and other gene based technologies used in DNA vaccines for Japonicum Schistosoma. Important technologies listed on the map include the use of reverse genetics to create reassorted viruses targeted for the use in veterinary applications. Additionally, the map suggests that numerous subunits exist for use in vaccines targeting cestodes, trematodes, and nematodes. Another major finding was that the number of patent documents related to helminths being published has been steadily increasing in the last decade, as shown in the figure below. Until the early-1990s, there were only a few helminth vaccine related patent documents being published each year. The number of publications increased noticeably when TRIPS took effect, resulting in publication of patent applications. However, since 2006 the number of vaccine publications has exploded. In the years 2011 and 2012, about 23 references disclosing parasitic worm vaccine technologies were published each year. Thus, interest in developing new and more efficacious helminth vaccines has been growing in recent years. The origin of the vaccine-related inventions was also analyzed. The team determined the country in which the priority application was filed, which was taken as an indication of the country where the invention was made or where the inventors intended to practice the invention. By far, most of the relevant families originated with patent applications filed in the United States and China. Other prominent priority countries were the United Kingdom, Japan, Brazil, Australia and France. Countries with the most filings were also analyzed. Countries that were heavily targeted for patent filings included the United States, Australia, Canada, and New Zealand. Top assignees for these families were mostly large pharmaceutical companies, with the majority of patent families coming from Heska, followed by Merck & Co., Institute Pasteur, AusBiotech Biotechnology, and Biological Sciences Research Council. Lastly, the jurisdictions were inventors have sought protection for their vaccine technologies were determined, and the number of patent families filing in a given country is plotted on the world map shown (Fig. 25). The United States, Canada, Australia, Japan, New Zealand and France have the highest level of filings, followed by Germany, Brazil, India, United Kingdom and Spain. However, although there are a significant number of filings in Brazil, the remainder of Central and South America has only sparse filings. Of concern, with the exception of South Africa, few other African nations have a significant number of filings. In summary, the goal of this report is to provide a knowledge resource for making informed policy decisions and for creating strategic plans concerning the assembly of vaccines targeting highly prevalent helminth infections. The ITTI team has defined the current state of the art of technologies involved in the manufacture of helminth vaccines, and the important assignees, inventors, and countries have been identified. This document should aid in evaluating the current state of vaccines technologies targeting helminths and the potential outgrows of these technological fields. Furthermore, as this report illustrates, the steady increase in helminth patenting, expanded diversity of assignees and greater global filings, indicates that intellectual property protection does not inhibit the development of crucial innovations for this class of neglected diseases, but, on the contrary, appears to be a driver of accelerated research and development

Vaccination against trypanosomiasis: Can it be done or is the trypanosome truly the ultimate immune destroyer and escape artist?

To date, human African trypanosomiasis (HAT) still threatens millions of people throughout sub-Sahara Africa, and new approaches to disease prevention and treatment remain a priority. It is commonly accepted that HAT is fatal unless treatment is provided. However, despite the well-described general symptoms of disease progression during distinct stages of the infection, leading to encephalitic complications, coma and death, a substantial body of evidence has been reported suggesting that natural acquired immunity could occur. Hence, if under favorable conditions natural infections can lead to correct immune activation and immune protection against HAT, the development of an effective anti-HAT vaccine should remain a central goal in the fight against this disease.<br /> In this review, we will (1) discuss the vaccine candidates that have been proposed over the past years, (2) highlight the main obstacles that an efficient anti-trypanosomiasis vaccine needs to overcome and (3) critically reflect on the validity of the widely used murine model for HAT

Kinetoplastids:related protozoan pathogens, different diseases

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

The potential for vaccines against scour worms of small ruminants

This review addresses the research landscape regarding vaccines against scour worms, particularly Trichostrongylus spp. and Teladorsagia circumcincta. The inability of past research to deliver scour-worm vaccines with reliable and reproducible efficacy has been due in part to gaps in knowledge concerning: (i) host-parasite interactions leading to development of type-2 immunity, (ii) definition of an optimal suite of parasite antigens, and (iii) rational formulation and administration to induce protective immunity against gastrointestinal nematodes (GIN) at the site of infestation. Recent ‘omics’ developments enable more systematic analyses. GIN genomes are reaching completion, facilitating “reverse vaccinology” approaches that have been used successfully for the Rhipicephalus australis vaccine for cattle tick, while methods for gene silencing and editing in GIN enable identification and validation of potential vaccine antigens. We envisage that any efficacious scour worm vaccine(s) would be adopted similarly to “Barbervax™” within integrated parasite management schemes. Vaccines would therefore effectively parallel the use of resistant animals, and reduce the frequency of drenching and pasture contamination. These aspects of integration, efficacy and operation require updated models and validation in the field. The conclusion of this review outlines an approach to facilitate an integrated research program

Identification of immunogenic proteins of the cysticercoid of Hymenolepis diminuta

Background: A wide range of molecules are used by tapeworm metacestodes to establish successful infection in the hostile environment of the host. Reports indicating the proteins in the cestode-host interactions are limited predominantly to taeniids, with no previous data available for non-taeniid species. A non-taeniid, Hymenolepis diminuta, represents one of the most important model species in cestode biology and exhibits an exceptional developmental plasticity in its life-cycle, which involves two phylogenetically distant hosts, arthropod and vertebrate. Results: We identified H. diminuta cysticercoid proteins that were recognized by sera of H. diminuta-infected rats using two-dimensional gel electrophoresis (2DE), 2D-immunoblotting, and LC-MS/MS mass spectrometry. Proteomic analysis of 42 antigenic spots revealed 70 proteins. The largest number belonged to structural proteins and to the heat-shock protein (HSP) family. These results show a number of the antigenic proteins of the cysticercoid stage, which were present already in the insect host prior to contact with the mammal host. These are the first parasite antigens that the mammal host encounters after the infection, therefore they may represent some of the molecules important in host-parasite interactions at the early stage of infection. Conclusions: These results could help in understanding how H. diminuta and other cestodes adapt to their diverse and complex parasitic life-cycles and show universal molecules used among diverse groups of cestodes to escape the host response to infection.Peer reviewe

Transcriptomic and proteomic analysis of Ascaris suum larvae during their hepato-tracheal migration

The gastro-intestinal nematodes Ascaris lumbricoides and Ascaris suum are amongst the most prevalent parasites of humans and pigs, respectively. Ascaris infections cause serious public health problems and significant economic losses in the pig industry. Traditionally ascariasis is controlled by mass treatment with anthelmintics. However, due to the short activity of the anthelmintics and an environment often highly contaminated with Ascaris eggs, reinfections can occur rapidly. In addition, the development of anthelmintic resistance which has been observed in other nematodes, suggests that current repeated doses of massive chemotherapy treatment will probably also lead to drug resistance in Ascaris spp. eventually. Therefore, investigation of the alternative means of ascariasis control such as vaccination is worthwhile for pursuing. To promote the rational development of an effective vaccine, a better understanding of the molecular biology and host-parasite relationships of Ascaris is required. In chapter two, a transcriptome dataset was generated and analyzed in order to identify both the highest transcribed and stage-specific transcripts for each larval stage, the metabolic changes and chemosensation pathways active in the larvae and, finally, the expression of potential molecular mimicry candidates. Illumina RNA sequencing of the A. suum infective-stage, liver-stage, lung-stage and intestinal-stage larvae resulted in 95,463,423 sequences yielding 18,543 contigs. Within the top 250 most highly transcribed contigs per stage, accounting for approximately 60% of the total transcription in each stage, cuticle collagens were by far the most abundant gene family. The analysis also identified a set of interesting stage-specific genes, such as venom allergen, chitinase, thioredoxin and cecropin, with a potentially important role in the host-parasite interaction processes. Analysis of the metabolic pathways showed that the degradation of complex carbohydrates likely forms an essential part of the energy metabolism of this parasite, as almost 10% of the total transcriptome of the L4 stage encodes for enzymes involved in this pathway. In comparison to Caenorhabditis elegans, a reduced number of olfactory molecules were identified in A. suum, in particular the aerotaxis molecules seem to absent, suggesting that they are less important for this parasite. Finally, 12 transcript sequences were identified as potential molecular mimicry candidates, including a suppressor of cytokine signaling family. Overall, the outcome of this transcriptomic analysis provides novel and valuable information regarding the biology of A. suum larvae, which can be used as a foundation for further research. In chapter three, we identified the excretory-secretory proteins of the migratory stages of A. suum utilizing LC-MS/MS. In total 106 proteins were identified, some of which are known as important players in the parasite-host interface. Interestingly, an abundance of glycosyl hydrolases was observed in the ES material of the intestinal L4 stage larvae. By combining the proteomic analysis with in-depth genomic, transcriptomic and enzymatic analyses we could show that the glycosyl hydrolase protein family has undergone a massive expansion in A. suum and that most of the glycolytic activity is present in the intestinal tissue of the adult parasites. Again, as already indicated by the transcriptomic analysis, this could suggest that the degradation of complex carbohydrates forms an essential part of the energy metabolism of this parasite once it establishes in the small intestine. In chapter four, we employed two different approaches, i.e. biotin labeling and enzymatic shaving, combined with LC-MS/MS to study the cuticle surface associated proteins of the infective stage larvae of A. suum. In total, 17 proteins were identified as surface associated proteins by the labeling approach. Many of these molecules had been previously reported as surface exposed proteins in other helminth species. On the other hand, the MS/MS spectra for the shaving approach only resulted in the identification of 3 genuine surface attached proteins, i.e. a cuticle collagen, a tubulin and a protein with unknown function. These results extended the knowledge on the biology of Ascaris larvae and their cuticle proteins, which play important roles in host-parasite interactions and hopefully it will benefit the development of novel intervention strategies. In conclusion, the transcriptomic and proteomic investigations performed in this thesis have led to a significant progress in our understanding of Ascaris biology. The most important observations were the potentially important role of carbohydrate metabolism in the larvae during their hepato-tracheal migration and the identification of the molecules essential to parasite survival and development. The study provides a basis for further molecular investigations aimed at exploring the biological role of the proteins identified and their potential as vaccine and/or therapeutic targets

Recombinant anticoccidial vaccines - a cup half full?

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