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Objective: To explore the effect of immunogenicity and immunizing protection of GAMA gene DNA vaccine, which was related with merozoite, ookinete and sporozoite invasion. Methods: Gene fragments were obtained using PCR technique and eukaryotic expression vector (containing immunostimulatory sequence) was built. BALB/c mice were divided into PBS control group, empty vector control group and study group and were immunized at week 0, 3 and 6 respectively. Blood was collected 2 weeks after each immunization and serum was separated to detect the IgG, IgG1 and IgG2a levels. Spleen of mice was obtained for preparation of splenic mononuclear cell and the cytokine IL-4 and IFN-γ levels were detected. Indirect immunofluorescence and western blot were employed to verify the specificity of antiserum. Sporozoite and merozoite invasion were used respectively to detect the immune protective effect 2 weeks after the third immunization. Ookinete conversion rate in vitro and oocyst numbers of mosquito stomach were observed to evaluate the transmission-blocking levels. Results: In GAMA DNA vaccine group: antiserum could be combined with recombinant protein specifically and green fluorescence signals of merozoite, ookinete and sporozoite were observable, while specific fragments and fluorescence signals were not observable in empty vector group. Compared with control group, specific IgG in DNA vaccine immunity group significantly increased (P < 0.01), and IgG1 and IgG2a all increased (P < 0.01). IL-4, IFN-γ content in study group significantly increased, compared with control group (P < 0.01). GAMA DNA vaccine immunity could not obviously block the erythrocyte-stage infection (caused by sporozoite invasion); compared with control group, liver worm load was slightly reduced (P < 0.05), and antiserum ookinete numbers (cultured in vitro) had no significant difference with oocyst numbers of mosquito stomach in DNA vaccine group. Conclusions: GAMA has good antigenicity, which could stimulate the body to produce specific immune responses; while DNA vaccine immunity could not play a good protective effect, the effect of which is only limited to the slight reduction of liver worm load, and has no obvious erythrocyte-stage protective effect and transmission-blocking effect. Therefore, trying other immunization strategies for further research on the value of GAMA (as multi-stage antigen vaccine and multi-stage combined vaccine components of the life-cycle of plasmodium) is necessary.
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OBJECTIVE@#To explore the effect of immunogenicity and immunizing protection of GAMA gene DNA vaccine, which was related with merozoite, ookinete and sporozoite invasion.@*METHODS@#Gene fragments were obtained using PCR technique and eukaryotic expression vector (containing immunostimulatory sequence) was built. BALB/c mice were divided into PBS control group, empty vector control group and study group and were immunized at week 0, 3 and 6 respectively. Blood was collected 2 weeks after each immunization and serum was separated to detect the IgG, IgG1 and IgG2a levels. Spleen of mice was obtained for preparation of splenic mononuclear cell and the cytokine IL-4 and IFN-γ levels were detected. Indirect immunofluorescence and western blot were employed to verify the specificity of antiserum. Sporozoite and merozoite invasion were used respectively to detect the immune protective effect 2 weeks after the third immunization. Ookinete conversion rate in vitro and oocyst numbers of mosquito stomach were observed to evaluate the transmission-blocking levels.@*RESULTS@#In GAMA DNA vaccine group: antiserum could be combined with recombinant protein specifically and green fluorescence signals of merozoite, ookinete and sporozoite were observable, while specific fragments and fluorescence signals were not observable in empty vector group. Compared with control group, specific IgG in DNA vaccine immunity group significantly increased (P < 0.01), and IgG1 and IgG2a all increased (P < 0.01). IL-4, IFN-γ content in study group significantly increased, compared with control group (P < 0.01). GAMA DNA vaccine immunity could not obviously block the erythrocyte-stage infection (caused by sporozoite invasion); compared with control group, liver worm load was slightly reduced (P < 0.05), and antiserum ookinete numbers (cultured in vitro) had no significant difference with oocyst numbers of mosquito stomach in DNA vaccine group.@*CONCLUSIONS@#GAMA has good antigenicity, which could stimulate the body to produce specific immune responses; while DNA vaccine immunity could not play a good protective effect, the effect of which is only limited to the slight reduction of liver worm load, and has no obvious erythrocyte-stage protective effect and transmission-blocking effect. Therefore, trying other immunization strategies for further research on the value of GAMA (as multi-stage antigen vaccine and multi-stage combined vaccine components of the life-cycle of plasmodium) is necessary.
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Objective To investigate the nasal colonization of Staphylococcus (S.) aureus strains among medical university students in Shenyang and to study the molecular epidemiological characteristics of methicillin resistant S. aureus (MRSA) strains. Methods Sterilized nasal swabs were used to collect nasal bacteria from both nares of the students. Nasal specimens were further identified as S. aureus strains, sensitive or resistant to methicillin through a series of tests. Molecular related methods including staphylococcal cassette chromosome mec (SCCmec) typing, pulsed- field gel electrophoresis (PFGE) , coagulase isotyping and minimum inhibitory concentration (MIC) determination etc. were used to characterize the isolates. Prevalence of the panton-valentine leukocidin (pvl) genes (lukS and F-PV) among the isolates was also assessed. Results Staphylococci were found in 488 specimens from 977 participants through the surveillance program, conducted in 2009. Of the 488 specimens being tested, 364 were identified as coagulase-negative staphylococci (CoNS) and 124 as S. aureus. MRSA strain among the S. aureus isolates was accounted for 3.4%. In the surveillance program conducted in 2010, staphylococci grew in 310 specimens fiom 657 participants. Of the 310 specimens tested, 195 were identified as CoNS and 115 as S. aureus. The percentage of MRSA strains among the S. aureus isolates was 7.7%. In total, 239 students carried S.aureus, and the percentage of MRSA carriers among the total specimens tested in this study was 5.1%.Most of the MRSA strains could be classified into one of the five types of SCCmec elements. Type Ⅳ a SCCmec strains were most frequent seen overall (10 isolates). A total of 11 pulsotypes were identified among the MRSA strains and were classified into 7 major groups (A to G) by the mutual correlations of their banding patterns. Ten MRSA strains were identified as pvl positive strains. Conclusion An MRSA clone (Ⅳ a SCCmec pulsotype A) carrying pvl toxin gene was found to be prevalent in the nares of the healthy university students.
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<p><b>BACKGROUND</b>The heavy incidence and mortality of hemorrhagic fever with renal syndrome, as well as no specific drugs in curing the disease, clearly indicate the need for development of the more effective hantavirus vaccine. Refining the DNA vaccination strategy to elicit more clinically efficacious immune responses is now under intensive investigation. In the present study, we examined the effects of using an interleukin-12 expression plasmid as a genetic adjuvant to enhance the immune responses induced by a DNA vaccine based on the S gene encoding nucleocapsid protein against hantavirus.</p><p><b>METHODS</b>BALB/c mice were immunized three times by intramuscular inoculations of DNA vaccine encoding of hantanvirus nucleocapsid protein alone or in combination with a plasmid expressing murine interleukin-12 (pcIL-12). Booster immunizations were employed 2 times at 2-week interval. To evaluate the humoral and cellular immune responses, antigen-specific lymphocyte proliferation and antibody production were assayed by MTT method and ELISA respectively. The level of interleukin-4 and interferon-gamma in the splenic lymphocytic cultured supernatant were detected with ELISA kit at day 5, 10, 17, 35 and 42 after primary immunization.</p><p><b>RESULTS</b>Antigen-specific IgG antibodies was increased markedly at day 17 in the experiment groups and reached a plateau after day 35. As pcIL-12 co-injected, a significant inhibition of antigen-specific IgG levels was displayed over the period and the antibody mean titre was decreased to only about 1:50 at day 42 after primary immunization, significantly lower than the group immunized with pcDNA3.1 + S alone, in which the mean titre was about 1:70. Interferon-gamma was increased remarkably by the co-injection of pcIL-12 compared with the injection of pcDNA3.1 + S alone. However, the production of interleukin-4 was inhibited by pcIL-12 co-injection. Furthermore, pcIL-12 co-injection efficiently enhanced antigen-specific lymphocyte proliferation.</p><p><b>CONCLUSION</b>Humoral and cytokine responses elicited by pcDNA3.1 + S inoculation can be modulated by co-inoculation with pcIL-12 and efficiently induced Th1-dominant immune responses.</p>
Subject(s)
Animals , Male , Mice , Cytokines , Genetic Therapy , Orthohantavirus , Allergy and Immunology , Immunoglobulin G , Blood , Immunophenotyping , Interleukin-12 , Genetics , Lymphocyte Activation , Mice, Inbred BALB C , Nucleocapsid , Genetics , Allergy and Immunology , Vaccines, DNA , Allergy and Immunology , Viral Vaccines , Allergy and ImmunologyABSTRACT
Problem-based learning(PBL)is an important part of creative education in medical colleges.Choice and design of cases are of the vital importance to success or failure of PBL course.To enhance students' ability of independent,creative thinking,and their ability of analyzing and solving problems,the roles of primitive cases and model cases as well as interrelation between them were discussed respective- ly.Moreover,five basic principles to be followed in model case design for PBL in Medical Microbiology and Human Parasitology,i.e.objec- tivity,flexibility,consistency,illumination and relevance,were proposed in this study.
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PBL teaching method is a new mode of teaching which is originated from the West and implemented into China in recent years with an expectation that it would mainly develop the students’ self-learning ability,and enhance their skills of comprehensive thinking and solving actual problems.The author summarizes the practical experience of using PBL teaching methods in the theory teaching in Department of Medical Microbiology and Human Parasitology,China Medical University in the past three years,and then proved this method is very helpful to improving the students’integrated thinking by analysis of sample.At the same time the results also suggested that the students showed high enthusiasm in discussing the cases.By this way,the students showed great subjective intiative in their studies.