Encapsulation of chimeric protein rSAG1/2 into poly(lactide-co-glycolide) microparticles induces long-term protective immunity against Toxoplasma gondii in mice

Microparticle Vaccines Against Toxoplasma gondii

“…The protein is encapsulated in 50:50 poly(lactide-co-glycolide) microparticles using the double emulsion method as described previously [41,42], with minor modifications [22][23][24]. In the process, PLG polymer is first dissolved in an organic solvent.…”

“…However, further improvements such as enhancement of protein load in PLG microparticles, as well as, optimization and stabilization of protein release are needed to evaluate the feasibility [40]. On the other hand, Western blotting assay with use of mouse monoclonal antibodies specific to tachyzoite SAGs demonstrated that released rSAG proteins from PLG microparticles still retained the original SAG antigenicity during the release from PLG microparticles [22][23][24]. These data indicate that both the encapsulation procedure and release from microparticles in our previous work are not detrimental to the antigenicity of …”

“…In our recent work, rSAG1, rSAG2, or rSAG1/2 was then, respectively, encapsulated with the PLG polymer by using the double emulsion method for production of PLG-encapsulated rSAG1 (PLG-rSAG1) [22], PLG-encapsulated rSAG2 (PLG-rSAG2) [ rSAG1/2 (PLG-rSAG1/2) microparticles [24]. Some microparticle characteristics, such as size (diameter), microparticle morphology, protein entrapment, and in vitro release were analyzed after PLG encapsulation (Tables 1 and 2).…”

“…Therefore, both SAG1 and SAG2 can be considered as potential candidate antigens for Toxoplasma vaccine development. SAG1 gene, SAG2 gene, and a hybrid gene consisting of SAG1 and SAG2 sequences had been, respectively, cloned in our previous work to produce recombinant SAG1 (rSAG1) protein [22,43], recombinant SAG2 (rSAG2) protein [23,43], and a recombinant chimeric protein, rSAG1/2 [24,43]. Further animal studies in mice demonstrated that rSAG1, rSAG2, or rSAG1/2 emulsified with an oil adjuvant, Vet L-10, induced partial protection against a lethal subcutaneous challenge of T. gondii tachyzoites [43].…”

“…In our recent work, recombinant SAGs (rSAGs), including rSAG1, rSAG2, and rSAG1/2, have been, respectively, encapsulated with the PLG polymer for production of PLG-encapsulated rSAG1 (PLG-rSAG1) [22], PLG-encapsulated rSAG2 (PLG-rSAG2) [23], or PLG-encapsulated rSAG1/2 (PLG-rSAG1/2) microparticles [24]. This chapter describes adjuvant effect of PLG microparticles, controlled release of PLG microparticles, PLG microparticles-immune system interaction, Toxoplasma SAG-loaded PLG microparticles, protective immunity by Toxoplasma SAG-loaded PLG microparticles, and future prospects.…”