A Recombinant Attenuated Salmonella enterica Serovar Typhimurium Vaccine Encoding Eimeria acervulina Antigen Offers Protection against E. acervulina Challenge

Abstract

Coccidiosis is a ubiquitous disease caused by intestinal protozoan parasites belonging to several distinct species of the genus Eimeria. Cell-mediated immunity (CMI) is critically important for protection against Eimeria; thus, our approach utilizes the bacterial type III secretion system (TTSS) to deliver an antigen directly into the cell cytoplasm of the immunized host and into the major histocompatibility complex class I antigenprocessing pathway for induction of CMI and antigen-specific cytotoxic T-lymphocyte responses in particular. To accomplish this goal, Eimeria genes encoding the sporozoite antigen EASZ240 and the merozoite antigen EAMZ250 were fused to the Salmonella enterica serovar Typhimurium effector protein gene sptP in the parental pYA3653 vector, yielding pYA3657 and pYA3658, respectively. SptP protein is secreted by the TTSS of Salmonella and translocated into the cytoplasm of immunized host cells. The host strain chromosomal copy of the sptP gene was deleted and replaced by a reporter gene, xylE. The newly constructed vectors pYA3657 and pYA3658 were introduced into host strain 8879 (⌬phoP233 ⌬sptP1033::xylE⌬ asdA16). This strain is an attenuated derivative of the highly virulent strain UK-1. When strain 8879(pYA3653) as the vector control and strain 8879 harboring pYA3657 or pYA3658 were used to orally immunize day-of-hatch chicks, colonization of the bursa, spleen, and liver was observed, with peak titers 6 to 9 days postimmunization. In vitro experiments show that the EASZ240 antigen is secreted into the culture supernatant via the TTSS and that it is delivered into the cytoplasm of Int-407 cells by the TTSS. In vivo experiments indicate that both humoral and cell-mediated immune responses are induced in chickens vaccinated with a recombinant attenuated Salmonella serovar Typhimurium vaccine, which leads to significant protection against Eimeria challenge.

Evaluation of new generationSalmonella entericaserovar Typhimurium vaccines with regulated delayed attenuation to induce immune responses against PspA

“…LPS profiles of Salmonella strains were examined as described (29). Plasmid stability was determined as previously described (30).…”

Immunogenicity of Recombinant Attenuated Salmonella enterica Serovar Typhimurium Vaccine Strains Carrying a Gene That Encodes Eimeria tenella Antigen SO7

“…In comparison, recombinant attenuated Salmonella vaccine (RASV) strains, which are able to harbor and deliver heterologous antigens, have several advantages. In addition to being safe, easy to administer, and affordable, they colonize the mucosa and other lymphoid tissues for prolonged periods of time and induce mucosal and systemic immune responses, both humoral and cell mediated (7,17,20,34). RASV strains have been used to immunize chicks with two Eimeria acervulina antigens, which resulted in induction of cell-mediated immune responses and protective immunity against E. acervulina challenge infection (20).…”

Bone morphogenetic protein 9 facilitates osteocarcinoma cell apoptosis and inhibits in vivo tumor growth

“…We used attenuated Salmonella, which has been used previously for the delivery of other therapeutic agents such as antigens, for gene delivery of pcDNA3.1 or pcDNA3.1-BMP9 (Dignam, 1990;Konjufca et al, 2006;Curtiss et al, 2010). In fact, attenuated Salmonella has been investigated for use in clinical trials for gene therapy (Lerman and Minna, 2000).…”