Sustained release of recombinant surface antigen 2 (rSAG2) from poly(lactide-co-glycolide) microparticles extends protective cell-mediated immunity against Toxoplasma gondii in mice

Shu-Chun Chuang; Chung-DA Yang

doi:10.1017/S0031182014000997

Sustained release of recombinant surface antigen 2 (rSAG2) from poly(lactide-co-glycolide) microparticles extends protective cell-mediated immunity against Toxoplasma gondii in mice

Parasitology. 2014 Oct;141(12):1657-1666. doi: 10.1017/S0031182014000997.

Authors

Shu-Chun Chuang¹, Chung-DA Yang²

Affiliations

¹ Department of Physiology, College of Medicine, Kaohsiung Medical University, No. 100, Shih-Chuan 1st Road, Kaohsiung 807, Taiwan.
² Graduate Institute of Animal Vaccine Technology, National Pingtung University of Science and Technology, No. 1, Shuefu Road, Neipu, Pingtung 912, Taiwan.

PMID: 25036078
DOI: 10.1017/S0031182014000997

Abstract

Current development efforts of subunit vaccines against Toxoplasma gondii, the aetiological agent of toxoplasmosis, have been focused mainly on tachyzoite surface antigens (SAGs) such as SAG2, due to their attachment roles in the process of host-cell invasion. In the present study, we aimed to produce poly(lactide-co-glycolide) (PLG) microparticles (MPs) containing recombinant SAG2 (rSAG2) to induce improved immunity against T. gondii. The resulting PLG-encapsulated rSAG2 (PLG-rSAG2) MPs, 2·14-3·63 μm in diameter, showed 74-80% entrapment efficiency and gradually released antigenic rSAG2 protein (88·3% of the total protein load) for a long 33-day period. Peritoneal immunization with PLG-rSAG2 MPs in BALB/c mice resulted in not only sustained (10 weeks) lymphocyte proliferation and IFN-γ production but also an improved protective capacity (87%) against a lethal subcutaneous challenge of 1×10⁴ live tachyzoites of T. gondii (RH strain). In conclusion, the sustained release of rSAG2 protein from PLG-rSAG2 MPs extends Th1 cell-mediated immunity (lymphocyte proliferation and IFN-γ production) and induces improved protection against T. gondii tachyzoite infection in mice.

Keywords: PLG-encapsulated rSAG2 microparticles (PLG-rSAG2 MPs); Toxoplasma gondii (T. gondii); cell-mediated immunity; poly(lactide-co-glycolide) (PLG); recombinant SAG2 (rSAG2).