Rhoptry antigens asToxoplasma gondiivaccine target

Abstract

Toxoplasmosis is a cosmopolitan zoonotic infection, caused by a unicellular protozoan parasite known as Toxoplasma gondii that belongs to the phylum Apicomplexa. It is estimated that over one-third of the world's population has been exposed and are latently infected with the parasite. In humans, toxoplasmosis is predominantly asymptomatic in immunocompetent persons, while among immunocompromised individuals may be cause severe and progressive complications with poor prognosis. Moreover, seronegative pregnant mothers are other risk groups for acquiring the infection. The life cycle of T. gondii is very complex, indicating the presence of a plurality of antigenic epitopes. Despite of great advances, recognize and construct novel vaccines for prevent and control of toxoplasmosis in both humans and animals is still remains a great challenge for researchers to select potential protein sequences as the ideal antigens. Notably, in several past years, constant efforts of researchers have made considerable advances to elucidate the different aspects of the cell and molecular biology of T. gondii mainly on microneme antigens, dense granule antigens, surface antigens, and rhoptry proteins (ROP). These attempts thereby provided great impetus to the present focus on vaccine development, according to the defined subcellular components of the parasite. Although, currently there is no commercial vaccine for use in humans. Among the main identified T. gondii antigens, ROPs appear as a putative vaccine candidate that are vital for invasion procedure as well as survival within host cells. Overall, it is estimated that they occupy about 1%–30% of the total parasite cell volume. In this review, we have summarized the recent progress of ROP-based vaccine development through various strategies from DNA vaccines, epitope or multi epitope-based vaccines, recombinant protein vaccines to vaccines based on live-attenuated vectors and prime-boost strategies in different mouse models.

The Impact of the Antigenic Composition of Chimeric Proteins on Their Immunoprotective Activity against Chronic Toxoplasmosis in Mice

“…A universal vaccine should protect hosts, including humans, from acute invasion and congenital toxoplasmosis. Thus, the vaccine should reduce the incidence of infection in both farm animals meant for human consumption and cats responsible for oocyst shedding and environmental contamination with infectious forms of T. gondii, which, in turn, is expected to minimize parasite transmission to all hosts, including humans [21]. However, despite many years of research, the construction of an effective and universal anti-Toxoplasma vaccine for use in both humans and animals remains an elusive goal.…”

Virus-like Particle Vaccine Containing Toxoplasma gondii Rhoptry Protein 13 Induces Protection against T. gondii ME49 Infection in Mice

“…An effective human vaccine against T. gondii infection is currently unavailable. DNA, subunit or protein vaccines against T. gondii have been studied but were unsuccessful [3,4]. As such, finding novel vaccines that are highly effective against T. gondii in-fection remains a great challenge for researchers.…”

“…In this study, we investigated the protective efficacy of T. gondii ROP13 vaccine generated in a virus-like particle form using ROP13, a protein secreted from the rhoptries which assists host cell invasion [4]. In this study, influenza VLPs expressing In general, memory B cells and plasma cells for specific antigens after immunization gradually decrease and are present at low levels.…”

Toxoplasma gondii ADSL Knockout Provides Excellent Immune Protection against a Variety of Strains

“…In recent years, genetically modified strains as vaccines have become a major research focus. Many scientists have begun to study genetically modified parasites, and the virulence of T. gondii was weakened by deleting certain genes, as has been achieved in some studies [18][19][20][21][22]. In addition, early studies have shown that T. gondii is a purine auxotroph organism [23,24].…”