Vaccine 29 (2011) 821–830 Contents lists available at ScienceDirect Vaccine journal homepage: www.elsevier.com/locate/vaccine Evaluation of three recombinant multi-antigenic vaccines composed of surface and secretory antigens of Toxoplasma gondii in murine models of experimental toxoplasmosis  Bozena Dziadek a,∗ , Justyna Gatkowska a , Anna Brzostek b , Jaroslaw Dziadek b , Katarzyna Dzitko a , Marcin Grzybowski a , Henryka Dlugonska a a Department of Immunoparasitology, University of Lodz, Lodz, Poland b Institute for Medical Biology, Polish Academy of Sciences, Lodz, Poland article info Article history: Received 18 January 2010 Received in revised form 16 July 2010 Accepted 2 November 2010 Available online 16 November 2010 Keywords: Toxoplasmosis Immunoprotection Recombinant T. gondii antigens Subunit vaccines abstract The great clinical and economical impact of Toxoplasma gondii infections makes the development of an effective vaccine for controlling toxoplasmosis an extremely important aim. In the presented study, we evaluate the protective and immunogenic properties of three recombinant subunit vaccines composed of rROP2 + rGRA4 + rSAG1, rROP2 + rROP4 + rGRA4 and rROP2 + rROP4 + rSAG1 proteins of T. gondii in an experimental toxoplasmosis model in the C3H/HeJ and C57BL/6 mouse strains. All three recombinant vaccines induced partial protection as measured by the reduction of brain cyst burden following challenge with five tissue cysts of the low virulence DX T. gondii strain. The level of protection was dependent on the antigen composition of the vaccine and the genetic background of the laboratory animals. The strongest protection against chronic toxoplasmosis was induced in both C3H/HeJ and C57BL/6 mice by the mixture of rhoptry proteins rROP2 and rROP4 combined with tachyzoite major protein rSAG1. The average parasite burden in these groups of mice was reduced by 71% and 90%, respectively, compared to non-vaccinated mice. The observed protective effect was related to the vaccine-induced cellular and humoral immune responses, as measured by the antigen-induced release of the Th1 cytokines IFN- and IL-2, the antigen- stimulated proliferation of spleen cells of vaccinated animals in comparison to control animals and the development of systemic antigen-specific IgG1 and IgG2a (C3H/HeJ) or IgG2c (C57BL/6) antibodies. Our studies show that recombinant rROP2, rROP4, rGRA4 and rSAG1 antigens may be promising candidates for a subunit vaccine against toxoplasmosis. Additionally, we demonstrate that the ideal composition of vaccine antigens can be equally effective in mice with different genetic backgrounds and variable levels of innate resistance to toxoplasmosis, resulting in strong protection against T. gondii invasion. © 2010 Elsevier Ltd. All rights reserved. 1. Introduction Toxoplasmosis is one of the world’s most widespread zoonoses, representing a serious clinical and veterinary problem. In immunocompetent people, infections with Toxoplasma gondii, the aetiological agent of toxoplasmosis, are usually asymptomatic or trigger only mild symptoms. However, such infections may lead to severe or even lethal damage in immunocompromised hosts such as AIDS patients, organ transplant recipients and patients with  This work is supported by The Polish Ministry of Science and Higher Education (Grant No. N N302 3196 33). ∗ Corresponding author at: Department of Immunoparasitology, University of Lodz, Banacha 12/16 Str., 90-237 Lodz, Poland. Tel.: +48 42 635 43 55; fax: +48 42 665 58 18. E-mail address: bodzia@biol.uni.lodz.pl (B. Dziadek). malignancies. Moreover, congenital toxoplasmosis as a result of primary infection acquired during gestation in the mother and ver- tical transmission of the parasite to the foetus through the placenta can result in retinochoroiditis, intracranial calcifications, hydro- cephalus, mental retardation and even spontaneous abortion and neonatal death [1–3]. In animals, infections with T. gondii cause stillbirth, abortion and neonatal loss in many kinds of livestock [4,5]. Additionally, the consumption of food contaminated with tis- sue cysts of T. gondii, such as meat or meat products from infected livestock, particularly poultry and pigs, is an important route of transmission to humans [6]. The great clinical and economic impact of toxoplasmosis makes the development of an effective vaccine for controlling this dis- ease an extremely important aim. Primary infection with T. gondii induces strong lifelong immunity, with IFN--producing CD8 + cytotoxic T lymphocytes considered the major effector cells for pro- tection against the parasite, suggesting that immunoprophylaxis of 0264-410X/$ – see front matter © 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.vaccine.2010.11.002