title: Evaluation of immune responses induced by SAG1 and MIC3 vaccine cocktails against Toxoplasma gondii.
abstract: The aim of this study was to evaluate the immune responses of a SAG1 and MIC3 vaccine cocktail in BALB/c mice. Ninety-six BALB/c mice were randomly divided into eight groups, including three plasmid DNA vaccine groups (pcDNA-MIC3, pcDNA-SAG1, pcDNA-MIC3+pcDNA-SAG1), three recombinant pseudotype baculovirus vaccine groups (BV-G-MIC3, BV-G-SAG1, BV-G-SAG1+BV-G-MIC3) and two control groups (PBS and BV-G-EGFP). All groups were immunized intramuscularly twice at three-week intervals. The production of anti-Toxoplasma gondii lysate antigen (TLA) antibodies, lymphoproliferation, levels of IFN-γ, IL-4 and IL-10 and the survival time were monitored after vaccination. The results showed that immunization of BALB/c mice with MIC3 and SAG1 vaccines stimulated both the cellular and humoral immune responses with the production of anti-T. gondii TLA antibodies. The vaccine cocktails of pcDNA-MIC3+pcDNA-SAG1 or BV-G-SAG1+BV-G-MIC3 induced significantly higher immunogenicity than a single-gene vaccine (P<0.05). Splenocytes from the immunized mice significantly proliferated in response to the TLA and released interferon (IFN)-γ (P<0.05). However, the levels of IL-4 and IL-10 in the sera of the immunized mice were not significantly different from those of the controls (P>0.05). Immunization with the vaccine cocktail (BV-G-SAG1+BV-G-MIC3) in mice significantly prolonged survival (50%; P<0.05) against a lethal challenge of T. gondii (RH tachyzoites), while all mice in the other immunized groups and control groups died within 20 and 4 days post-infection, respectively. Furthermore, the recombinant pseudotype baculovirus vaccines induced better immunogenicity than the plasmid DNA vaccines (P<0.05). These results suggest that an excellent vector-mediated vaccine cocktail strategy might be used to develop a new generation of vaccines against T. gondii infection.
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei, PR China.
authors.forename: Rui
authors.initials: R
authors.lastname: Fang
authors.forename: Hanli
authors.initials: H
authors.lastname: Feng
authors.forename: Min
authors.initials: M
authors.lastname: Hu
authors.forename: Muhammad Kasib
authors.initials: MK
authors.lastname: Khan
authors.forename: Lixia
authors.initials: L
authors.lastname: Wang
authors.forename: Yanqin
authors.initials: Y
authors.lastname: Zhou
authors.forename: Junlong
authors.initials: J
authors.lastname: Zhao
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000276:immunology*; D016367:Baculoviridae; D049109:Cell Proliferation; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation / Q000276:immunology; D007074:Immunoglobulin G / Q000097:blood; D008214:Lymphocytes / Q000166:cytology / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D010957:Plasmids; D015800:Protozoan Proteins / Q000276:immunology*; D016052:Protozoan Vaccines / Q000276:immunology*; D013154:Spleen / Q000166:cytology; D014122:Toxoplasma / Q000276:immunology* / Q000378:metabolism; D014124:Toxoplasmosis, Animal / Q000097:blood / Q000276:immunology / Q000517:prevention & control*
chemical_list: D000953:Antigens, Protozoan; D016207:Cytokines; D007074:Immunoglobulin G; C421382:MIC3 protein, Toxoplasma gondii; D015800:Protozoan Proteins; D016052:Protozoan Vaccines; C047168:SAG1 antigen, Toxoplasma