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Induction of long-lasting protective immunity against Toxoplasma gondii in BALB/c mice by recombinant surface antigen 1 protein encapsulated in poly (lactide-co-glycolide) microparticles.

Chuang SC, Ko JC, Chen CP, Du JT, Yang CD - Parasit Vectors (2013)

Bottom Line: We examined the ability of PLG-rSAG1 microparticles to induce and prolong effective anti-Toxoplasma immune responses, in comparison with rSAG1 formulated with a Vet L-10 adjuvant (rSAG1 (Vet L-10)).PLG-rSAG1 microparticles can effectively induce not only significant long-lasting SAG1-specific humoral and cell-mediated immune responses but also high protection against T. gondii tachyzoite infection.Our study provides a valuable basis for developing long-lasting vaccines against T. gondii for future use in humans and animals.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physiology, College of Medicine, Kaohsiung Medical University, No 100, Shih-Chuan 1st Road, Kaohsiung 807, Taiwan.

ABSTRACT

Background: Current development efforts of subunit vaccines against Toxoplasma gondii, the etiological agent of toxoplasmosis, have been focused mainly on tachyzoite surface antigen 1 (SAG1). Since microparticles made from poly (lactide-co-glycolide) (PLG) polymers have been developed as safe, potent adjuvants or delivery systems, we aimed to encapsulate recombinant SAG1 (rSAG1) with the PLG polymers to prepare PLG-encapsulated rSAG1 (PLG-rSAG1) microparticles that would sustain rSAG1 release and generate long-lasting protective immunity against T. gondii in BALB/c mice.

Methods: In the present study, rSAG1 was encapsulated into PLG microparticles by the double emulsion method. PLG-rSAG1 microparticles were then intraperitoneally injected twice at a 14-day interval into BALB/c mice. We examined the ability of PLG-rSAG1 microparticles to induce and prolong effective anti-Toxoplasma immune responses, in comparison with rSAG1 formulated with a Vet L-10 adjuvant (rSAG1 (Vet L-10)). Eight weeks after the last immunization, protective activities were also evaluated after a lethal subcutaneous challenge of 1 x 10(4) live T. gondii tachyzoites.

Results: PLG-rSAG1 microparticles, 4.25~6.58 micrometers in diameter, showed 69%~81% entrapment efficiency. The amount of released rSAG1 protein from microparticles increased gradually over a 35-day period and the protein still retained native SAG1 antigenicity. Intraperitoneal vaccination of mice with the microparticles resulted in enhanced SAG1-specific IgG titers as well as lymphocyte proliferation and, more importantly, these enhanced activities were maintained for 10 weeks. In addition, eight weeks after the last immunization, maximum production of gamma interferon was detected in mice immunized with PLG-rSAG1 microparticles. Furthermore, 80% (8/10) of mice immunized with PLG-rSAG1 microparticles survived at least 28 days after a lethal subcutaneous tachyzoite challenge.

Conclusions: Encapsulation of rSAG1 into PLG microparticles preserves the native SAG1 antigenicity and sustains the release of rSAG1 from microparticles. PLG-rSAG1 microparticles can effectively induce not only significant long-lasting SAG1-specific humoral and cell-mediated immune responses but also high protection against T. gondii tachyzoite infection. Our study provides a valuable basis for developing long-lasting vaccines against T. gondii for future use in humans and animals.

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Analysis of purified rSAG1 by Western blotting. Purified rSAG1 was prepared as described in the Methods and analyzed with anti-SAG1 mouse mAb TG-1 (lane 1). Standard protein markers (lane M) are shown at the left.
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Figure 1: Analysis of purified rSAG1 by Western blotting. Purified rSAG1 was prepared as described in the Methods and analyzed with anti-SAG1 mouse mAb TG-1 (lane 1). Standard protein markers (lane M) are shown at the left.

Mentions: After cloning, the induced GST-SAG1 protein was purified and its tag GST protein was removed. The resulting rSAG1 protein was analyzed by Western blot analysis using the mouse mAb TG-1, which is specific to SAG1 of T. gondii tachyzoites. The result demonstrated that rSAG1 protein (30 kDa) prepared in the present study showed the native SAG1 antigenicity recognized by the mouse mAb TG-1 (Figure1).


Induction of long-lasting protective immunity against Toxoplasma gondii in BALB/c mice by recombinant surface antigen 1 protein encapsulated in poly (lactide-co-glycolide) microparticles.

Chuang SC, Ko JC, Chen CP, Du JT, Yang CD - Parasit Vectors (2013)

Analysis of purified rSAG1 by Western blotting. Purified rSAG1 was prepared as described in the Methods and analyzed with anti-SAG1 mouse mAb TG-1 (lane 1). Standard protein markers (lane M) are shown at the left.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3584932&req=5

Figure 1: Analysis of purified rSAG1 by Western blotting. Purified rSAG1 was prepared as described in the Methods and analyzed with anti-SAG1 mouse mAb TG-1 (lane 1). Standard protein markers (lane M) are shown at the left.
Mentions: After cloning, the induced GST-SAG1 protein was purified and its tag GST protein was removed. The resulting rSAG1 protein was analyzed by Western blot analysis using the mouse mAb TG-1, which is specific to SAG1 of T. gondii tachyzoites. The result demonstrated that rSAG1 protein (30 kDa) prepared in the present study showed the native SAG1 antigenicity recognized by the mouse mAb TG-1 (Figure1).

Bottom Line: We examined the ability of PLG-rSAG1 microparticles to induce and prolong effective anti-Toxoplasma immune responses, in comparison with rSAG1 formulated with a Vet L-10 adjuvant (rSAG1 (Vet L-10)).PLG-rSAG1 microparticles can effectively induce not only significant long-lasting SAG1-specific humoral and cell-mediated immune responses but also high protection against T. gondii tachyzoite infection.Our study provides a valuable basis for developing long-lasting vaccines against T. gondii for future use in humans and animals.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physiology, College of Medicine, Kaohsiung Medical University, No 100, Shih-Chuan 1st Road, Kaohsiung 807, Taiwan.

ABSTRACT

Background: Current development efforts of subunit vaccines against Toxoplasma gondii, the etiological agent of toxoplasmosis, have been focused mainly on tachyzoite surface antigen 1 (SAG1). Since microparticles made from poly (lactide-co-glycolide) (PLG) polymers have been developed as safe, potent adjuvants or delivery systems, we aimed to encapsulate recombinant SAG1 (rSAG1) with the PLG polymers to prepare PLG-encapsulated rSAG1 (PLG-rSAG1) microparticles that would sustain rSAG1 release and generate long-lasting protective immunity against T. gondii in BALB/c mice.

Methods: In the present study, rSAG1 was encapsulated into PLG microparticles by the double emulsion method. PLG-rSAG1 microparticles were then intraperitoneally injected twice at a 14-day interval into BALB/c mice. We examined the ability of PLG-rSAG1 microparticles to induce and prolong effective anti-Toxoplasma immune responses, in comparison with rSAG1 formulated with a Vet L-10 adjuvant (rSAG1 (Vet L-10)). Eight weeks after the last immunization, protective activities were also evaluated after a lethal subcutaneous challenge of 1 x 10(4) live T. gondii tachyzoites.

Results: PLG-rSAG1 microparticles, 4.25~6.58 micrometers in diameter, showed 69%~81% entrapment efficiency. The amount of released rSAG1 protein from microparticles increased gradually over a 35-day period and the protein still retained native SAG1 antigenicity. Intraperitoneal vaccination of mice with the microparticles resulted in enhanced SAG1-specific IgG titers as well as lymphocyte proliferation and, more importantly, these enhanced activities were maintained for 10 weeks. In addition, eight weeks after the last immunization, maximum production of gamma interferon was detected in mice immunized with PLG-rSAG1 microparticles. Furthermore, 80% (8/10) of mice immunized with PLG-rSAG1 microparticles survived at least 28 days after a lethal subcutaneous tachyzoite challenge.

Conclusions: Encapsulation of rSAG1 into PLG microparticles preserves the native SAG1 antigenicity and sustains the release of rSAG1 from microparticles. PLG-rSAG1 microparticles can effectively induce not only significant long-lasting SAG1-specific humoral and cell-mediated immune responses but also high protection against T. gondii tachyzoite infection. Our study provides a valuable basis for developing long-lasting vaccines against T. gondii for future use in humans and animals.

Show MeSH
Related in: MedlinePlus