Cloning and expression of Neospora caninum rhoptry 2 and its potential as an immunobiological for neosporosis control / Clonagem e expressão de rhoptry 2 Neospora caninum e seu potencial como um imunobiológico para o controle de neosporose

The protozoan Neospora caninum is known worldwide as one of the main causes of abortion in cattle. During infection, rhoptry proteins present in the apical complex of the parasite play important roles in adhesion and parasitophorous vacuole formation. The use of N. caninum ROP2 in experimental vaccines has shown promising protective results. In our study we performed cloning and expression in Escherichia coli of an antigenic portion of N. caninum ROP2. The recombinant protein (rROP2) was obtained in insoluble form, and the purified protein showed a size of approximately 18kDa. Even being a small truncate NcROP2 region, it was possible to conserve the antigenic epitopes which were recognized by bovine serum naturally infected with N. caninum. Vaccination with rROP2 on aluminum hydroxide adjuvant induced high levels of rROP2-specific IgG antibodies capable of recognizing native protein in tachyzoite lysates. In conclusion, our approaches were effective in obtaining the rROP2 protein, which induced specific mouse immune response and was also recognized by sera from N. caninum naturally infected cattle. These results suggest that it is a promising antigen for the development of neosporosis subunit vaccines as well as a suitable antigen for use in immunodiagnosis.(AU)

O protozoário Neospora caninum é conhecido mundialmente como uma das principais causas de aborto em bovinos. Durante a infecção, as proteínas rhoptry presentes no complexo apical do parasita desempenham papel importante na adesão e formação de vacúolos parasitóforos. O uso de ROP2 de N. caninum em vacinas experimentais tem mostrado resultados de proteção promissores. Em nosso estudo, realizamos a clonagem e expressão em Escherichia coli de uma porção antigênica de N. caninum ROP2. A proteína recombinante (rROP2) foi obtida na forma insolúvel, e a proteína purificada apresentou tamanho aproximado de 18kDa. Mesmo sendo uma pequena região truncada de NcROP2, foi possível conservar os epítopos antigênicos que foram reconhecidos pelo soro de bovinos naturalmente infectados com N. caninum. A vacinação com rROP2 adsorvida no adjuvante de hidróxido de alumínio induziu altos níveis de anticorpos IgG anti-rROP2, capazes de reconhecer a proteína nativa em lisados de taquizoítos. Em conclusão, nossas abordagens foram eficazes na obtenção da proteína rROP2, que induziu resposta imune específica em camundongos e também foi reconhecida por soros de bovinos naturalmente infectados com N. caninum. Estes resultados sugerem que rROP2 é um antígeno promissor para o desenvolvimento de vacinas de subunidades de neosporose, bem como um antígeno adequado para uso em imunodiagnóstico.(AU)

Cloning and expression of Neospora caninum rhoptry 2 and its potential as an immunobiological for neosporosis control

ABSTRACT: The protozoan Neospora caninum is known worldwide as one of the main causes of abortion in cattle. During infection, rhoptry proteins present in the apical complex of the parasite play important roles in adhesion and parasitophorous vacuole formation. The use of N. caninum ROP2 in experimental vaccines has shown promising protective results. In our study we performed cloning and expression in Escherichia coli of an antigenic portion of N. caninum ROP2. The recombinant protein (rROP2) was obtained in insoluble form, and the purified protein showed a size of approximately 18kDa. Even being a small truncate NcROP2 region, it was possible to conserve the antigenic epitopes which were recognized by bovine serum naturally infected with N. caninum. Vaccination with rROP2 on aluminum hydroxide adjuvant induced high levels of rROP2-specific IgG antibodies capable of recognizing native protein in tachyzoite lysates. In conclusion, our approaches were effective in obtaining the rROP2 protein, which induced specific mouse immune response and was also recognized by sera from N. caninum naturally infected cattle. These results suggest that it is a promising antigen for the development of neosporosis subunit vaccines as well as a suitable antigen for use in immunodiagnosis.

RESUMO: O protozoário Neospora caninum é conhecido mundialmente como uma das principais causas de aborto em bovinos. Durante a infecção, as proteínas rhoptry presentes no complexo apical do parasita desempenham papel importante na adesão e formação de vacúolos parasitóforos. O uso de ROP2 de N. caninum em vacinas experimentais tem mostrado resultados de proteção promissores. Em nosso estudo, realizamos a clonagem e expressão em Escherichia coli de uma porção antigênica de N. caninum ROP2. A proteína recombinante (rROP2) foi obtida na forma insolúvel, e a proteína purificada apresentou tamanho aproximado de 18kDa. Mesmo sendo uma pequena região truncada de NcROP2, foi possível conservar os epítopos antigênicos que foram reconhecidos pelo soro de bovinos naturalmente infectados com N. caninum. A vacinação com rROP2 adsorvida no adjuvante de hidróxido de alumínio induziu altos níveis de anticorpos IgG anti-rROP2, capazes de reconhecer a proteína nativa em lisados de taquizoítos. Em conclusão, nossas abordagens foram eficazes na obtenção da proteína rROP2, que induziu resposta imune específica em camundongos e também foi reconhecida por soros de bovinos naturalmente infectados com N. caninum. Estes resultados sugerem que rROP2 é um antígeno promissor para o desenvolvimento de vacinas de subunidades de neosporose, bem como um antígeno adequado para uso em imunodiagnóstico.

Protection against Toxoplasma gondii cysts in pigs immunized with rROP2 plus Iscomatrix / Proteção contra cistos de Toxoplasma gondii em suínos imunizados com rROP2 associado à Iscomatrix

Abstract This study aimed to evaluate the humoral immune response in pigs immunized intranasally and intramuscularly with recombinant Toxoplasma gondii rROP2 protein in combination with the adjuvant Iscomatrix. Twelve mixed breed pigs divided into three groups (n=4) were used, G1 received recombinant ROP2 proteins (200 µg/dose) plus Iscomatrix, G2 received PBS plus Iscomatrix, and G3 as the control group. The intranasal (IN) and intramuscular (IM) routes were used. Animals were challenged orally with VEG strain oocysts and treated on day three after challenge. Fever, anorexia, and prostration were the clinical signs observed in all animals. All the G1 animals produced antibodies above the cut-off on the day of the challenge, while the G2 and G3 remained below the cut-off. Better partial protection against parasitemia and cyst tissue formation was observed in G1 than G3. The protection factors against tissue cyst formation were 40.0% and 6.1% for G1 and G2, respectively, compared to G3. In conclusion, there were not systemic antibody responses in pigs with IN immunization with rROP2+Iscomatrix; however, after IM immunization, those animals produced higher titers than animal controls. We associated these results with partial protection obtained against parasitemia and tissue cysts formation.

Resumo O objetivo deste estudo foi avaliar a resposta imune humoral em suínos imunizados pelas vias intranasal e intramuscular com proteínas recombinantes rROP2 do Toxoplasma gondii associadas ao adjuvante Iscomatrix. Doze suínos cruzados divididos em 3 grupos (n=4) foram utilizados. O G1 recebeu proteína recombinante ROP2 (200mg/dose) associada ao adjuvante Iscomatrix; o G2 recebeu PBS associado ao Iscomatrix; e o G3 foi o grupo controle. As vias intranasal (IN) e intramuscular (IM) foram utilizadas. Os animais foram desafiados por via oral com a cepa VEG e tratados no dia três após o desafio. Febre, anorexia e prostração foram os sinais clínicos observados em todos os animais. Todos os animais do G1 produziram anticorpos acima do ponto de corte no dia do desafio, enquanto os animais do G2 e G3 permaneceram abaixo do ponto de corte no desafio. Proteção parcial contra parasitemia e formação de cistos teciduais foram observadas nos suínos do G1 comparados ao G3. Os fatores de proteção contra a formação de cistos teciduais foram 40,0% e 6,1% no G1 e G2, respectivamente, comparados com o G3. Como conclusão, não houve estimulação da resposta imune humoral sistêmica nos suínos após as imunizações IN com rROP2+Iscomatrix. Estes animais, porém, após a imunização IM, produziram títulos de anticorpos mais altos que os animais controles. Esses resultados foram associados a uma proteção parcial contra a parasitemia e formação de cistos teciduais.

Virus-like Particle Vaccine Containing Toxoplasma gondii Rhoptry Protein 13 Induces Protection against T. gondii ME49 Infection in Mice

Toxoplasma gondii can infect humans worldwide, causing serious diseases in pregnant women and immunocompromised individuals. T. gondii rhoptry protein 13 (ROP13) is known as one of the key proteins involved in host cell invasion. In this study, we generated virus-like particles (VLPs) vaccine expressing T. gondii rhoptry ROP13 and investigated VLPs vaccine efficacy in mice. Mice immunized with ROP13 VLPs vaccine elicited significantly higher levels of T. gondii-specific IgG, IgG1, IgG2a, and IgA antibody responses following boost immunization and challenge infection, whereas antibody inductions were insignificant upon prime immunization. Differing immunization routes resulted in differing antibody induction, as intranasal immunization (IN) induced greater antibody responses than intramuscular immunization (IM) after boost and challenge infection. IN immunization induced significantly higher levels of IgG and IgA antibody responses from feces, antibody-secreting cells (ASCs), CD4⁺ T, CD8⁺ T cells and germinal center B cell responses in the spleen compared to IM immunization. Compared to IM immunization, IN immunization resulted in significantly reduced cyst counts in the brain as well as lesser body weight loss, which contributed to better protection. All of the mice immunized through either route survived, whereas all naïve control mice perished. These results indicate that the ROP13 VLPs vaccine could be a potential vaccine candidate against T. gondii infection.

Research status of rhoptry protein of Toxoplasma gondii and its nucleic acid vaccine / 中国血吸虫病防治杂志

At present,there are no ideal drugs and measures in the treatment and prevention of toxoplasmosis.The develop-ment of safe,convenient,and strong protective nucleic acid vaccine is an important strategy for prevention and control of toxo-plasmosis.The rhoptry protein(ROP)is a large class of proteins secreted by Toxoplasma gondii.ROPs play an important role in the invasion of host cells,the formation of parsitophorous vacuole(PV)and the regulation of proliferation by T.gondii.Thus, ROPs become the most promising candidates of vaccine.In this paper,we summarize the important members of the ROPs,the expression vector and the immunogenicity and immunoprotection of the nucleic acid vaccine in animal experiments.

Virus-Like Particles Expressing Toxoplasma gondii Rhoptry Protein 18 Induces Better Protection Than Rhoptry Protein 4 against T. gondii Infection

Toxoplasma gondii is a ubiquitous protozoan parasite responsible for causing toxoplasmosis. Preventive measures for toxoplasmosis are currently lacking and as such, development of novel vaccines are of urgent need. In this study, we generated 2 virus-like particles (VLPs) vaccines expressing T. gondii rhoptry protein 4 (ROP4) or rhoptry protein 18 (ROP18) using influenza matrix protein (M1) as a core protein. Mice were intranasally immunized with VLPs vaccines and after the last immunization, mice were challenged with ME49 cysts. Protective efficacy was assessed and compared by determining serum antibody responses, body weight changes and the reduction of cyst counts in the brain. ROP18 VLPs-immunized mice induced greater levels of IgG and IgA antibody responses than those immunized with ROP4 VLPs. ROP18 VLPs immunization significantly reduced body weight loss and the number of brain cysts in mice compared to ROP4 VLPs post-challenge. These results indicate that T. gondii ROP18 VLPs elicited better protective efficacy than ROP4 VLPs, providing important insight into vaccine design strategy.

The research status of rhoptry proteins vaccine of vectors mediated Toxoplasma gondii / 中华地方病学杂志

Toxoplasmosis caused by Toxoplasma gondii is one type of zoonotic, parasitic diseases seriously endangering human health. Vaccine recently becomes the highlight in control of this parasite. ROPs antigen is an effective candidate molecule of vaccine. This review outlines the status in the research of ROPs vaccine of Toxoplasma gondii mediated by bacteria such as Lactococcus lactis, Mycobacteria smegmatis, Bacille calmette-Guerin, Agrobacterium tumefaciens and Pichia Pastoris, and viruses such as Canine adenovirus type 2, Adenovirus serotype 5, Feline herpesvirus type-1 and Vaccinia virus.

Multilevel Precision-Based Rational Design of Chemical Inhibitors Targeting the Hydrophobic Cleft of Toxoplasma gondii Apical Membrane Antigen 1 (AMA1)

Toxoplasma gondii is an intracellular Apicomplexan parasite and a causative agent of toxoplasmosis in human. It causes encephalitis, uveitis, chorioretinitis, and congenital infection. T. gondii invades the host cell by forming a moving junction (MJ) complex. This complex formation is initiated by intermolecular interactions between the two secretory parasitic proteins—namely, apical membrane antigen 1 (AMA1) and rhoptry neck protein 2 (RON2) and is critically essential for the host invasion process. By this study, we propose two potential leads, NSC95522 and NSC179676 that can efficiently target the AMA1 hydrophobic cleft, which is a hotspot for targeting MJ complex formation. The proposed leads are the result of an exhaustive conformational search-based virtual screen with multilevel precision scoring of the docking affinities. These two compounds surpassed all the precision levels of docking and also the stringent post docking and cumulative molecular dynamics evaluations. Moreover, the backbone flexibility of hotspot residues in the hydrophobic cleft, which has been previously reported to be essential for accommodative binding of RON2 to AMA1, was also highly perturbed by these compounds. Furthermore, binding free energy calculations of these two compounds also revealed a significant affinity to AMA1. Machine learning approaches also predicted these two compounds to possess more relevant activities. Hence, these two leads, NSC95522 and NSC179676, may prove to be potential inhibitors targeting AMA1-RON2 complex formation towards combating toxoplasmosis.

Prokaryotic expression and identification of rhoptry protein 38 of Toxoplas-ma gondii / 中国血吸虫病防治杂志

Objective To explore the biological function of rhoptry protein 38(ROP38)of Toxoplasma gondii,and to iden?tify the reactogenicity of the recombinant protein(rROP38). Methods The ROP38 was amplified by RT?PCR from T. gondii RH strain,and was cloned into prokaryotic expression vector pET?28a(+). The recombinant plasmid was transformed into E. co?li BL21(DE3)competent cells. Then the rROP38 was analyzed by SDS?PAGE and identified by Western blot. Results SDS?PAGE showed that rROP38 was efficient expression with a molecular weight of about 43 kD. Western blot showed that rROP38 reacted with antibody of His tag or human positive antibody,which indicated that ROP38 had good reactogenicity and could be a serological diagnostic antigen. Conclusion The study successfully obtains the rROP38 of T. gondii with good reactogenicity.

Evaluation of a recombinant rhoptry protein 2 enzyme-linked immunoassay for the diagnosis of toxoplasmosis acquired during pregnancy

The aim of this study was to evaluate an enzyme-linked immunoassay with recombinant rhoptry protein 2 (ELISA-rROP2) for its ability to detectToxoplasma gondii ROP2-specific IgG in samples from pregnant women. The study included 236 samples that were divided into groups according to serological screening profiles for toxoplasmosis: unexposed (n = 65), probable acute infection (n = 48), possible acute infection (n = 58) and exposed to the parasite (n = 65). When an indirect immunofluorescence assay forT. gondii-specific IgG was considered as a reference test, the ELISA-rROP2 had a sensitivity of 61.8%, specificity of 62.8%, predictive positive value of 76.6% and predictive negative value of 45.4% (p = 0.0002). The ELISA-rROP2 reacted with 62.5% of the samples from pregnant women with probable acute infection and 40% of the samples from pregnant women with previous exposure (p = 0.0180). Seropositivity was observed in 50/57 (87.7%) pregnant women with possible infection. The results underscored that T. gondii rROP2 is recognised by specific IgG antibodies in both the acute and chronic phases of toxoplasmosis acquired during pregnancy. However, the sensitivity of the ELISA-rROP2 was higher in the pregnant women with probable and possible acute infections and IgM reactivity.

Construction and identification of pcDNA3-HBsAg-p30-ROP2 expression vec-tor / 中国血吸虫病防治杂志

Objective To construct a multi-gene recombinant pcDNA3-HBsAg-p30-ROP2 expression vector and identify it preliminarily. Methods According to recombinant pcDNA3-p30-ROP2 restriction sites,HBV HBsAg gene sequences of primers were designed and synthesized to amplify target fragment,and then cloned into pcDNA3-HbsAg-p30-ROP2 expression vector. Af-ter sequencing,it was identified finally by restriction enzyme digestion and other molecular biology techniques. Results HBV HBsAg gene segment was amplified by PCR and the multi-gene recombinant pcDNA3-HBsAg-p30-ROP2 expression vector was constructed and identified to be correct as theoretical values. The PCR and restriction enzyme digestion results showed that HBsAg and p30-ROP2 gene in recombinant plasmid were confirmed by DNA sequencing. Conclusion The multi-gene recombinant pcD-NA3-HBsAg-p30-ROP2 expression vector is successfully constructed.

Pseudokinases secreted by rhoptry in Toxoplasma gondii / 中国人兽共患病学报

Toxoplasma gondii rhoptry proteins (ROPs) include dozens of proteins secreted by tachyzoites ,these ROPs are known to be critical for several processes such as invasion ,parasitophorous vacuole establishment ,proliferation ,egress and getting out of host immune protection .ROPs belong to the protein kinase family and have classic kinase domain ,however ,most of the members are designated as pseudokinases due to the lack of critical catalytic residues that are normally required for phos-phorylation of host signal molecules .Recent studies indicated that pseudokinases also have important functions ,such as regula-ting kinase activity by allosteric and promoting the interactions between proteins as scaffolds .In this paper ,we summarize the pseudokinases structural characteristics and some pseudokinases functions ,for the study of toxop lasma gondii and host interac-tion mechanisms ,molecular vaccines screening and drugs design .

Research progress of interaction between Toxoplasma gondii rhoptry pro-teins and host cells / 中国血吸虫病防治杂志

Rhoptry proteins are the major virulence factors of Toxoplasma gondii. They locate in different parts of the host cells and can affect the membrane cytoskeleton structure and active factors of the host cells so as to block the cell intrinsic de-fense mechanisms of the host and let T. gondii invade parasitize and proliferate in the host successfully. The function and ac-tion mode of rhoptry proteins reflect the pathogenic mechanism of T. gondii which holds great significance to looking for toxo-plasmosis drug targets and developing molecule vaccines. This paper reviews the research progess of the interaction between rhoptry proteins of T. gondii and host cells.

Gefitinib Inhibits the Growth of Toxoplasma gondii in HeLa Cells

Toxoplasma gondii is the causative agent of toxoplasmosis with symptoms of congenital neurological and ocular diseases and acquired lymphadenitis, retinochoroiditis, and meningoencephalitis. Small molecules which block the activity of protein kinases were tested in in vitro culture of T. gondii to find new therapeutic drugs of safer and more effective than the combined administration of pyrimethamine and sulfadoxine that sometimes provoke lethal Stevens-Johnson syndrome. Among them, Gefitinib and Crizotinib inhibited intracellular growth of T. gondii in HeLa cells by counting the number of T. gondii per parasitophorous vacuolar membrane whereas Sunitinib did not. Gefitinib inhibited the growth of T. gondii in a dose-dependent manner over 5 microM up to the tolerable concentration of HeLa cells and halted the division of the parasite immediately from the time point of treatment. Gefitinib inhibition suggests that tyrosine kinases of EGFR family or other homologous kinases of the parasite itself may be the target to cause the block of T. gondii growth.

Toxoplasma gondii: humoral and cellular immune response of BALB/c mice immunized via intranasal route with rTgROP2 / Toxoplasma gondii: avaliação da resposta imune humoral e celular de camundongos BALB/c imunizados pela via nasal com rTgROP2

TgROP2 is an intracellular protein associated with rhoptries of Toxoplama gondii and an antigen component of a candidate vaccine for toxoplasmosis. The purpose of the present study was to evaluate the efficacy of rTgROP2 to stimulate humoral and cellular immune responses in BALB/c mice via intranasal injection. TgROP2 partial coding sequence was (196-561) amplified by PCR from genomic T. gondii RH strain DNA and cloned into the pTrcHis expression vector. Escherichia coli Rosetta 2 cells transformed with pTrcHis-TgROP2 showed high levels (~1 mg.mL-1) of recombinant protein after 4 hours of IPTG induction. Recombinant TgROP2 exhibited an apparent Mr equal to 54 kDa. In order to test immunogenicity of the recombinant protein, 10 BALB/c mice received 10 µg of rROP2 protein + 10 µg of Quil-A via intranasal injection. Doses were administered at days 0, 21, and 42. Three animals were euthanized and used to evaluate cell-ular immune response on day 62. Five (50 percent) and two (20 percent) out of ten animals produced IgG (DO mean = 0.307; cut-off = 0.240) and IgA (DO mean = 0.133, cut-off = 0.101), respectively, by ELISA on day 62. The proliferation of splenocytes revealed high stimulation index (SI) when co-cultured with 5, 10 and 15 µg.mL-1 of rTgROP2. These results indicate that intranasal immunization with recombinant protein ROP2 plus Quil-A can elicit both cellular and humoral immune responses in BALB/c mice.

TgROP2 é uma proteína localizada nas roptrias do Toxoplasma gondii, sendo um antígeno candidato a componente de uma vacina contra a toxoplasmose. O objetivo do presente estudo foi avaliar a eficácia da TgROP2 recombinante em estimular a resposta imune celular e humoral de camundongos BALB/c após estímulo intranasal. A sequência da TgROP2 foi amplificada pela PCR a partir da cepa RH e clonada em vetor de expressão pTrc-His. Após a transformação em Escherichia coli- Rosetta 2, a pTrcHis-TgROP2 exibiu alto nível de expressão após 4 horas de indução com IPTG. A proteína recombinante apresentou uma massa molecular aparente de aproximadamente 54 kDa. Para avaliar a imunogenicidade dessa proteína recombinante, 10 camundongos receberam, pela via intranasal, 10 µg da rROP2 associado a 10 µg de Quil-A. Três doses foram realizadas nos dias 0, 21 e 42. No dia 62 do experimento, três animais foram eutanasiados para avaliar as respostas imune celular e humoral. Cinco (50 por cento) e dois (20 por cento) dos 10 animais apresentaram níveis de IgG (DO média = 0,307; ponto de corte = 0,240) e IgA (DO média = 0,133; ponto de corte = 0,101) acima do ponto de corte no ELISA no dia 62. A proliferação de esplenócitos revelou altos Índices de Estimulação (SI), quando as células foram cultivadas com 5, 10 e 15 µg.mL-1 de rTgROP2. Os resultados obtidos indicam que a via nasal pode estimular tanto a resposta imune celular como a humoral.

Improving the production of the denatured recombinant N-terminal domain of rhoptry-associated protein 2 from a Plasmodium falciparum target in the pathology of anemia in falciparum malaria

Rhoptry-associated protein 2 (RAP2) is known to be discharged from rhoptry onto the membrane surface of infected and uninfected erythrocytes (UEs) ex vivo and in vitro and this information provides new insights into the understanding of the pathology of severe anemia in falciparum malaria. In this study, a hexahistidine-tagged recombinant protein corresponding to residues 5-190 of the N-terminal of Plasmodium falciparum RAP2 (rN-RAP2) was produced using a new method of solubilization and purification. Expression was induced with D-lactose, a less expensive alternative inducer to the more common isopropyl-²-D-thio-galactopyranosidase. The recombinant protein was purified using two types of commercially-available affinity columns, iminodiacetic and nitrilotriacetic. rN-RAP2 had immunogenic potential, since it induced high titers of anti-RAP2 antibodies in mice. These antibodies recognized full-length RAP2 prepared from Triton X-100 extracts from two strains of P. falciparum. In fact, the antibody recognized a 29-kDa product of RAP2 cleavage as well as 82 and 70-kDa products of RAP1 cleavage. These results indicate that the two antigens share sequence epitopes. Our expressed protein fragment was shown to contain a functional epitope that is also present in rhoptry-derived ring surface protein 2 which attaches to the surface of both infected and UEs and erythroid precursor cells in the bone marrow of malaria patients. Serum from malaria patients who developed anemia during infection recognized rN-RAP2, suggesting that this protein fragment may be important for epidemiological studies investigating whether immune responses to RAP2 exacerbate hemolysis in falciparum malaria patients.

STUDIES ON IMMUNO-RESPONSE OF DNA VACCINATION WITH RECOMBINANT PLASMID pcDNA3 CONTAINING ROP1 GENE FROM TOXOPLASMA GONDII IN BALB/C MICE IV. The Detecting of IFN-γ,IL-2,and NO in the Serum from the Immunized Mice / 中国人兽共患病学报

Aim DNA vaccinating BALB/c mice with the constructed recombinant plasmid, pcDNA3, containing ROP1 gene from Toxoplasma gondii to observe the effect on the production of the cytokines, IFN- γ、 IL - 2 , and NO in the immunized mice. Methods Large-scale preparation of plasmid DNA by alkaline lysis,the DNA were injected through muscles of left leg in each mouse at the dosage of 100μg. A booster vaccine was given at the same dosage after two weeks. Control groups were injected with pcDNA3 blank plasmid and normal saline respectively. After 30,50 and 70 days of the booster injection, following tests were carried out 3 times separately :the serum IFN-γand IL-2 were detected by sandwich ELISA;the NO was detected by enzyme assay. Results The 3 times detected results of IFN-γγ、IL-2 and NO were significant higher in the vaccinated group than that of in control groups and the contents were increased with the vaccinated time prolonged. Conclusion The IFN - γγ、 IL - 2 and NO were produced by vaccinating BALB/c mice with the recombinant plasmid, pcROP1.

Studies on the Immuno-Protection of ROP2 Nuclei Acid Vaccine in Toxoplasma gondii Infection / 中国寄生虫学与寄生虫病杂志

Objective To study the protective effect of ROP2 nuclei acid vaccine in mice.Methods Forty-two BALB/c mice were divided into three groups.Each mouse in experiment group was injected with 50 ?g recombinant plasmid pc-DNA3-ROP2 through musculus quadriceps fexoris.In control groups,each mouse was injected with 50 ?g blank plasmid pc-DNA3 and with 50 ?l PBS respectively.All mice were immunized for three times with an interval of three weeks.The volume was doubled for the final injection in the two plasmid groups.Blood,spleens and lymph nodes of 4 mice in each group were taken for the detection of CD4+,CD8+ T cells and cytokines 2 weeks after the final immunization.The rest mice in 3 groups were challenged with 500 tachyzoites of Toxoplasm gondii RH strain for further observation.Results The vaccine induced strong cellular and humoral immune response.The titer of antibody in serum was high after inoculation and recognized ROP2 protein antigen expressed in vitro.The lymphocyte phenotype was analyzed.CD4+ T cells proliferated sharply(69.5?3.4)%,and the ratio of CD4+/CD8+ increased considerably by(4.69?1.32)%(P