FIELD OF INVENTION

The present invention is related to the fields of parasitology and vaccinology and more specifically to mucosal immunity in relation to parasitology and vaccinology.

BACKGROUND OF THE INVENTION

Coccidiosis in poultry is a common disease which has global importance in the commercial industry. Coccidiosis is caused by parasites of the genusEimeria, belonging to Phylum Apicomplexa and continues to be one of the most economically important diseases in today's poultry industry facilitating a need to develop safe and effective vaccines which do not compromise productivity. The apicomplexan phylum of protozoa, characterized by the presence of an apical complex, contains numerous parasites of veterinary (Cryptosporidium, Neospora, Eimeria) and medical (Plasmodium, Cryptosporidium, Toxoplasma) importance.Eimeriassp. are the causative agent of coccidiosis, which continues to be one of the most important enteric diseases in the commercial poultry industry, with losses to the industry estimated to be $800 million worldwide and $450 million in the United States annually. Coccidiosis manifests in the gastrointestinal tract (GIT), resulting in severe diarrhea and affecting growth performance with subsequent increases in feed conversion ratio and mortality in poultry. The life cycle ofEimeriais complex and involves both intracellular and extracellular stages. EachEimeriaspp., colonizes specific areas of the GIT depending on its tissue tropism.

Coccidiosis is primarily a disease that affects young animals but can affect older animals that are immune compromised. It occurs commonly in confined conditions but can occur in free-ranging conditions that have congregating areas, such as feeding, shade and watering areas. Coccidiosis causes substantial economic losses due to reduced performance, death from direct infections, and by predisposing poultry to secondary bacterial and viral infections, such assalmonellosis, or respiratory diseases. The labor demand for the treatment and care of infected poultry in addition to medication costs amplify the economic losses.

Conventional approaches of disease control have employed prophylactic medications in the form of chemotherapy, antibiotics, anticoccidials and selection of disease resistant strains of chickens. However, with the ability of parasites to develop drug resistance, research into alternative methods of disease prevention and control continue. In this regard, vaccination against coccidiosis has become a key aspect of present research. Current commercial vaccines are hindered by their complex production processes and species-specific protection.

Immunity to the disease is complex and involves many facets of the host immune system. There is definite interplay between humoral and cell-mediated immunity, even though it is accepted that cell-mediated immunity is most important. The parasite is known to colonize the intestinal epithelium and hence, the primary line of host defense is mucosal associated lymphoid tissue (MALT). The mucous membranes constitute the major portal of entry for infectious agents and include membranes of the respiratory, gastrointestinal, and genitourinary tract as well as the ocular conjunctiva, the inner ear, and the ducts of all exocrine glands. Collectively they cover more than 400 m2in humans and serve as the first line of defense against infection at the entry points for a variety of pathogens. The gastrointestinal system is the largest lymphoid organ in the body containing an estimated 70% to 80% of the body's immunoglobulin-producing cells. 80% of all the activated B cells in the body are located at the mucosal tissues.

The concept of a common mucosal immune system predicts that induction of immunity at one mucosal surface, such as the gut, can provide immunity at another mucosal surface, such as the lung providing a necessary link for immunity transfer throughout mucosal surfaces. Increasing evidence has indicated that mucosal vaccination can induce both systemic and local mucosal immunity, while systemic immunization generally fails to elicit strong mucosal immunity. Vaccines which are administered through a mucosal route of entry and are able to elicit mucosal, humoral, and cell-mediated immune responses offer a promising alternative approach when compared with existing traditional (inactivated subcutaneous or attenuated total pathogen oral) vaccine strategies.

The life cycle ofEimeriaspp., is complex and involves both intracellular and extracellular stages. The parasite is known to colonize the intestinal epithelium and hence, the primary line of host defense is the MALT. Immunity to the disease is complex and involves many facets of the host immune system. There is definite interplay between humoral and cell-mediated immunity, even though it is accepted that cell-mediated immunity is most important. Species ofEimeriaare potently immunogenic and are capable of eliciting a strong immune response.

Thus, there is clearly a need for both a product and method which alleviates parasitic affliction and coccidiosis.

SUMMARY OF THE INVENTION

The instant invention includes a vaccine for the protection of poultry against coccidiosis comprising an amino acid sequence as shown in SEQ ID Nos.: 1 through 9. Vaccines according to the present invention may be comprised within a vector, such as a virus, bacterium, or liposome.

The instant invention includes methods of enhancing the immune response against coccidiosis in a subject by administering a vaccine according to the present invention.

The instant invention also includes methods of reducing morbidity associated with infection with coccidiosis in a subject by administering a vaccine according to the present invention.

The instant invention includes vaccine for the protection of poultry against one or more Apicomplexan parasites comprising an amino acid sequence as shown in SEQ ID Nos.: 1 through 9 and a pharmaceutically acceptable carrier. Vaccines according to the present invention may be comprised within a vector, such as a virus, bacterium, or liposome.

The instant invention includes methods of enhancing the immune response against one or more Apicomplexan parasites in a subject by administering a vaccine according to the present invention.

The instant invention also includes methods of reducing morbidity associated with infection with one or more Apicomplexan parasites in a subject by administering a vaccine according to the present invention.

