Toxoplasma gondi is thought to infect all nucleated cells in warm-blooded animals,including poultry,mammals,and humans.However,it is unclear whether T.gondi can infect chicken erythrocytes due to the nucleated nature ...Toxoplasma gondi is thought to infect all nucleated cells in warm-blooded animals,including poultry,mammals,and humans.However,it is unclear whether T.gondi can infect chicken erythrocytes due to the nucleated nature of these cells.Due to the special role of chicken erythrocytes in innate immunity,we investigated the cell-cell interaction between T.gondi and erythrocytes to elucidate the role of chicken erythrocytes in T.gondi infection.Cellular apoptosis was analyzed by transwell assay and flow cytometry.An immunofluorescence method was used to examine the reorganization of vimentin during T.gondi infection in both Vero cells and chicken erythrocytes.The reorganization of actin was evaluated to further examine the invasion capacity of tachyzoites on chicken erythrocytes during infection.We discovered that T.gondi can adhere to but not invade chicken erythrocytes and eventually cause apoptosis in chicken erythrocytes.When tachyzoites were cocultured with chicken erythrocytes in vitro,the transcrip-tional levels of T.gondi MIC3,ROP16,and ROP18 were significantly decreased.In addition,the rearrangement of host cell vimentin,a type Il cytoskeleton protein regulated by T.gondii infection,was not observed.Similarly,the parasite-induced ring-shaped actin structure was not formed in the host-parasite junction.T.gondi(RH strain)tachyzoites pref-erentially invaded Vero cells and replicated in chicken blood monocytes,but they were not found in chicken erythro-cytes.These findings showed that although T.gondi could attach to the surface of chicken erythrocytes,but couldn't invade successfully.Interestingly,we found that the T.gondii secretome,lysates,and intact tachyzoites could cause apoptosis of chicken erythrocytes,which suggested a complex mechanism involved in the apoptosis of chicken erythrocytes induced by T.gondi.This study elucidated that T.gondi could not infect nucleated chicken erythrocytes and enriched our understanding of the transmission mechanism of T.gondii among avian species.展开更多
To characterize the immune response induced by SAG1 encoding plasmid combined with IL 2 gene adjuvant in mice and to assess the protective effect of this vaccination against toxoplasmosis Methods Mice were co inje...To characterize the immune response induced by SAG1 encoding plasmid combined with IL 2 gene adjuvant in mice and to assess the protective effect of this vaccination against toxoplasmosis Methods Mice were co injected intramuscularly with plasmid encoding Toxoplasma gondii SAG1 plus murine IL 2 expression vector at a dose of 100 μg Booster immunizations were employed 2 more times at 3 week interval As controls, mice were inoculated with PBS or empty plasmid pcDNA3 Humoral and cellular responses were assayed using ELISA for the determination of Ab, Ab isotype and IFN γ, as well as IL 4 To detect the integration and dissemination of DNA in the injected mice, PCR and in situ hybridization were performed All mice were then infected with highly virulent RH tachyzoites of Toxoplasma gondii intraperitoneally Results Significant increases in specific IgG levels were observed in mice after immunization three times with SAG1 expression plasmid With respect to the IgG isotype, co inoculation of IL 2 expression plasmid enhanced the level of IgG2a and the production of IFN γ Challenging mice by vaccinating with combined plasmids with RH tachyzoites resulted in prolonged survival Conclusion Humoral and cytokine responses elicited by SAG1 DNA immunization can be modulated by co inoculation with IL 2 expression plasmid The use of DNA vaccine in combination with an appropriate cytokine gene to prevent T gondii infection warrants further investigation展开更多
基金This work was supported by grants from the National Key Research and Development Program of China(2022YFD1800200)the National Natural Science Foundation of China(Grant Numbers 32072891,31672546,31902297)+2 种基金Education Department of Liaoning Province Project(LSNQN202003,LUKZ0673)Shenyang Young and middle-aged Scientific and technological Innovation Talent Support Program(RC210291)Key Laboratory for prevention and control of Avian Influenza and Other Major Poultry Diseases,Ministry of Agriculture and Rural Affairs,PR.China and Key Laboratory of Livestock Disease Prevention of Guangdong Province(YDWS202209).
文摘Toxoplasma gondi is thought to infect all nucleated cells in warm-blooded animals,including poultry,mammals,and humans.However,it is unclear whether T.gondi can infect chicken erythrocytes due to the nucleated nature of these cells.Due to the special role of chicken erythrocytes in innate immunity,we investigated the cell-cell interaction between T.gondi and erythrocytes to elucidate the role of chicken erythrocytes in T.gondi infection.Cellular apoptosis was analyzed by transwell assay and flow cytometry.An immunofluorescence method was used to examine the reorganization of vimentin during T.gondi infection in both Vero cells and chicken erythrocytes.The reorganization of actin was evaluated to further examine the invasion capacity of tachyzoites on chicken erythrocytes during infection.We discovered that T.gondi can adhere to but not invade chicken erythrocytes and eventually cause apoptosis in chicken erythrocytes.When tachyzoites were cocultured with chicken erythrocytes in vitro,the transcrip-tional levels of T.gondi MIC3,ROP16,and ROP18 were significantly decreased.In addition,the rearrangement of host cell vimentin,a type Il cytoskeleton protein regulated by T.gondii infection,was not observed.Similarly,the parasite-induced ring-shaped actin structure was not formed in the host-parasite junction.T.gondi(RH strain)tachyzoites pref-erentially invaded Vero cells and replicated in chicken blood monocytes,but they were not found in chicken erythro-cytes.These findings showed that although T.gondi could attach to the surface of chicken erythrocytes,but couldn't invade successfully.Interestingly,we found that the T.gondii secretome,lysates,and intact tachyzoites could cause apoptosis of chicken erythrocytes,which suggested a complex mechanism involved in the apoptosis of chicken erythrocytes induced by T.gondi.This study elucidated that T.gondi could not infect nucleated chicken erythrocytes and enriched our understanding of the transmission mechanism of T.gondii among avian species.
文摘To characterize the immune response induced by SAG1 encoding plasmid combined with IL 2 gene adjuvant in mice and to assess the protective effect of this vaccination against toxoplasmosis Methods Mice were co injected intramuscularly with plasmid encoding Toxoplasma gondii SAG1 plus murine IL 2 expression vector at a dose of 100 μg Booster immunizations were employed 2 more times at 3 week interval As controls, mice were inoculated with PBS or empty plasmid pcDNA3 Humoral and cellular responses were assayed using ELISA for the determination of Ab, Ab isotype and IFN γ, as well as IL 4 To detect the integration and dissemination of DNA in the injected mice, PCR and in situ hybridization were performed All mice were then infected with highly virulent RH tachyzoites of Toxoplasma gondii intraperitoneally Results Significant increases in specific IgG levels were observed in mice after immunization three times with SAG1 expression plasmid With respect to the IgG isotype, co inoculation of IL 2 expression plasmid enhanced the level of IgG2a and the production of IFN γ Challenging mice by vaccinating with combined plasmids with RH tachyzoites resulted in prolonged survival Conclusion Humoral and cytokine responses elicited by SAG1 DNA immunization can be modulated by co inoculation with IL 2 expression plasmid The use of DNA vaccine in combination with an appropriate cytokine gene to prevent T gondii infection warrants further investigation
