Recent progress in microneme-based vaccines development againstToxoplasma gondii

Abstract

Toxoplasmosis is a cosmopolitan zoonotic disease, which infect several warm-blooded mammals. More than one-third of the human population are seropositive worldwide. Due to the high seroprevalence of Toxoplasma gondii infection worldwide, the resulting clinical, mental, and economical complications, as well as incapability of current drugs in the elimination of parasites within tissue cysts, the development of a vaccine against T. gondii would be critical. In the past decades, valuable advances have been achieved in order to identification of vaccine candidates against T. gondii infection. Microneme proteins (MICs) secreted by the micronemes play a critical role in the initial stages of host cell invasion by parasites. In this review, we have summarized the recent progress for MIC-based vaccines development, such as DNA vaccines, recombinant protein vaccines, vaccines based on live-attenuated vectors, and prime-boost strategy in different mouse models. In conclusion, the use of live-attenuated vectors as vehicles to deliver and express the target gene and prime-boost regimens showed excellent outcomes in the development of vaccines against toxoplasmosis, which need more attention in the future studies.

A systematic review on efficiency of microneme proteins to induce protective immunity against Toxoplasma gondii

“…DNA vaccines, however, induce primarily potent cytotoxic T cell responses and have been showed to have limited ability in overall protection, especially when utilized in primates [58]. In a review, Foroutan and collaborators reported that a heterologous prime-boost strategy, especially a DNA vaccine as a priming and a protein-based vaccine for booster, induces more cellular and humoral immune responses than the homologous prime-boost [67].…”

Epitope-based vaccine as a universal vaccination strategy against Toxoplasma gondii infection: A mini-review

“…Similarly, the effect of 60 Co-irradiated tachyzoites on the stimulation of protective immunity against the Beverley strains of T. gondii was investigated. The vaccine induced partial resistance after infection challenge; however, the vaccine showed disadvantages, such as the need for refrigeration and high costs [34]. Oocyst shedding was not reduced when DNA vaccines encoding rhoptry protein (ROP) 2 were used [35] even though DNA vaccine currently shows potential as an immunization tool.…”

“…The establishments of DNA vaccination strategies have opened a new perspective in the future of vaccine development [34,44]. Recently, various DNA vaccines against T. gondii have been developed and evaluated; some of them have shown promise [45].…”

Rhomboid antigens are promising targets in the vaccine development against Toxoplasma gondii

“…Accordingly, the development of an effective vaccine has high priority for investigators to limit the infection in animals and humans. During the three past decades, non-stop efforts of researchers have made great achievements in the identification and development of T. gondii candidate vaccines mainly on rhoptry proteins (ROPs), surface antigens (SAGs), microneme proteins (MICs), dense granule antigens (GRAs), calcium-dependent protein kinases (CDPKs), and some other antigens (Foroutan and Ghaffarifar, 2018[ 15 ]; Foroutan et al, 2018[ 18 ], 2019[ 16 ]; Kur et al, 2009[ 30 ]; Zhang et al, 2015[ 50 ]).…”

“…In the past several years, the different vaccine types with various strategies have been developed experimentally throughout the globe that ranged from killed vaccines, live or attenuated vaccines, recombinant subunit proteins, live vectors to DNA vaccines or multiepitope-based vaccines (Foroutan and Ghaffarifar, 2018[ 15 ]; Foroutan et al, 2019[ 16 ]; Ghaffarifar, 2015[ 21 ], 2018[ 20 ]; Kur et al, 2009[ 30 ]; Zhang et al, 2015[ 50 ]). These vaccines with various vaccination routes in different mouse models have verified partial protection and reduction of brain cysts burden after challenge with avirulent and/or virulent Toxoplasma strains (Foroutan and Ghaffarifar, 2018[ 15 ]; Foroutan et al, 2018[ 18 ]; Han et al, 2017[ 24 ]; Kur et al, 2009[ 30 ]; Li et al, 2012[ 32 ]; Zhang et al, 2015[ 50 ]; Zhang et al, 2015[ 51 ]). However, currently there is a lack of an approved commercial vaccine for human use (Zhang et al, 2015[ 50 ]).…”