Parasitic Vaccines

Creative Biolabs can offer high-quality Parasitic Vaccines for use in prevention of parasitic diseases. Parasitic diseases are global problems and considered to be a major obstacle to harming health and reducing productivity of animals. Parasites that live inside the body, such as mites, ticks, fleas, lice and flies are responsible for organ condemnation, zoonoses and huge economic losses in animal production. Various control methods have been implemented to minimize or inhibit loss caused by parasitic diseases. Vaccination is considered one of the best alternatives for control of parasites in the future. In order to develop commercial vaccines against economically important parasites, the researchers have focused on identifying target antigens so far. Some of these involve ticks salivary gland antigens, secretory and excretory antigens of helminthes and hidden antigens of Heamonchus contortus.

As a result of this effort, several candidate antigens have been identified, vaccines are prepared from them and tested for efficacy and suitability. Over the past few years, significant progress has been made in developing vaccines for three major tropical parasitic diseases (malaria, leishmaniasis and schistosomiasis).

The development of immune in parasitic infections depends on factors including breed, individual genetic makeup, age and several characteristics of co-infected nematode species. However, effective vaccines are not yet available. The difficulty in developing vaccines against parasitic diseases is to identify (and produce) appropriate protective antigens because of the lack of complete understanding of the type of immune response required for protection. Despite these barriers, a number of candidate vaccines are under development for each disease; at least one promising candidate vaccine is in late clinical testing.

Types of Parasitic Vaccine

• Live Vaccines

The virulence of the parasitic strains derived from a single isolate could be variable. Attenuation can also be generated by repeated passage in vitro. Many parasitic species have complex life cycle, characterized by different life cycle stage, sometimes involving more than one host. Inducing protective immune selection of parasitic strains with truncated lifecycles at the early life cycle stage with adequate immunogenicity is another strategy for vaccine development. Live vaccines may also be developed from parasites that cause chronic infections. In this case, the parasite exhibits a long-term survival trend in the host, in which case chemotherapy is required to treat the infection.

• Killed Vaccines

Killed vaccines are more stable and have longer shelf life. The vaccine can be prepared from the entire organism or their parts or products. Killed vaccines usually do not induce protective immunity by themselves, so an appropriate adjuvant and formulation must be developed. In these cases, special attention must be paid to the safety of the adjuvant used. If no live vaccine strains are available, or the use of live vaccines is undesirable, it may be necessary to inactivate the parasite prior to formulation of the vaccine.

• Subunit and Recombinant Vaccines

Subunit and recombinant vaccines are composed of certain key molecules that manipulate the host immune response by blocking the function of these molecules to prevent the establishment of parasites in the host. In recent years the development of subunit and recombinant vaccines have made substantial progress.

Table 1. Parasitic vaccines commercially produced. ^[1]

Vaccine development against parasitic diseases has been slow to progress until recently. It faces several basic challenges like the isolation of native antigens from none blood feeders which elicit protective immunity if delivered to the immune system in an appropriate manner. Protein separation, hybridoma technology, monoclonal antibody production and advances in recombinant DNA technology are now being used for parasite identification and production of molecular defined candidate vaccines. The slow progress is largely due to the difficulty of culturing protozoa and helminths in vitro and in vivo, which is being rapidly overcome now. The use of parasitic vaccines in the future will not only help protect people from these diseases but also reduce the detrimental effects of continued, intensive chemical applications in the environment.

Reference

1. Sharma N; et al. Role of parasitic vaccines in integrated control of parasitic diseases in livestock. Vet World. 2015, 8(5): 590-8.

All of our products can only be used for research purposes. These vaccine ingredients CANNOT be used directly on humans or animals.