Preliminary Study On Infection Of Chicken Red Blood Cells By Toxoplasma Gondii

As a specialized intracellular parasitic protozoan,Toxoplasma gondii is widely parasitic in the nucleated cells of the tissues outside the red blood cells of most mammals.Birds and poultry are susceptible animals of Toxoplasma gondii.The infection rate of Toxoplasma gondii in domestic free-range chickens is as high as 30%.People who infect and consume chicken-related products can infect Toxoplasma gondii,and the harm to humans and animals should not be underestimated.Toxoplasma can infect different types of nucleated cells of different hosts.At present,there are very few studies on the invasion of red blood cells by Toxoplasma gondii.Only in 1980,Takada found that Toxoplasma gondii can multiply in immature red blood cells.He studied mouse red blood cells as research object.Toxoplasma gondii proliferation in vitro at different developmental stages(Takada S,1980).He found that Toxoplasma gondii can multiply in the nucleated red blood cells of the fetal rat liver,the enucleated reticulo cytes,and the reticulocytes in the blood.Moreover,birds are susceptible to Toxoplasma gondii,and their red blood cells are different from mammalian red blood cells.They are nucleated red blood cells,but little research has been done on whether toxoplasma can invade nucleated red blood cells.In this experiment,through continuous culture observation,the process of invading nucleated cells and infecting chicken red blood cells by continuous observation of Toxoplasma gondii for a long time,it was found that Toxoplasma gondii caused lysis and death of chicken red blood cells in vitro culture;With the normal temperature and temperature of chickens and the influence of cell types on Toxoplasma gondii invasion rate,it was found that temperature did not affect the invasion rate of Toxoplasma gondii,and it did not affect the erythrocyte lysis and death caused by Toxoplasma gondii;the invasion rate of Toxoplasma gondii invasion Hela cells was more common.The nucleated cells are slow,but will not affect the invasion and proliferation,indicating that Toxoplasma gondii may selectively invade;further through in vitro co-culture experiments and chicken vein challenge experiments,it is found that when nucleated cells coexist with chicken red blood cells,Toxoplasma will first Invasion of nucleated cells,and then once again proved that in the natural state,Toxoplasma gondii preferentially invaded nucleated cells and did not invade chicken red blood cells;Q-PCR was used to detect the transcription level of related virulence factors of Toxoplasma gondii infecting chicken red blood cells,and found Partial virulence factors ROP16,ROP18 and MIC3 were compared with in vitro cultured toxoplasma in mice There was a significant difference in the recorded levels,and the transcription level was low when co-cultured with Toxoplasma gondii,which indirectly proved that Toxoplasma gondii could not invade chicken red blood cells;by indirect immunofluorescence experiments,we found that the toxoplasma was invaded from Vero cells,and the cell surface membrane protein Vimentin was from the beginning.The distribution around the nucleus gradually accumulates around the vacuolar membrane of the larvae,but this phenomenon does not occur when the chicken red blood cells are infested,which confirms that the Toxoplasma gondii cannot invade the chicken red blood cells.