ABSTRACT
@#Objective To construct encoding RNA that can be cyclized in vitro by using the permuted intron exon(PIE)strategy in the maturation process of eukaryotic mRNA,and transfect it into HEK-293T cells for expression.Methods The sequences of 5'and 3'cyclic arms with groupⅠcatalytic intron,the internal ribosome entry sites(IRES)of Coxsackievirus B3(CVB3)and the target gene were selected to construct the template plasmid. Linearization plasmid template obtained by PCR was used to synthesize linear RNA through in vitro transcription(IVT),which then started in vitro cyclization(IVC)by the addition of cyclization reagents to obtain circular RNA(circRNA). RNA cyclization was confirmed by agarose gel electrophoresis and ribonuclease R(RNase R)digestion. HEK-293T cells were transfected with circRNAs respectively carrying enhanced green fluorescent protein(EGFP),firefly luciferase(Fluc),and influenza virus hemagglutinin(HA)IVR-180 genes,to verify their expression with in vitro.Results With RNA cyclization,the main band of agarose gel electrophoresis became smaller and small fragments appeared. After RNase R digestion,only some circRNA bands remained.HEK-293T cells transfected with EGFP-circRNA showed significant green fluorescence under the fluorescence microscope.The Fluc expression values of HEK-293T cells transfected with Fluc-circRNA were on average 20 times higher than non cyclized RNA,and the relative light unit(RLU)scaled up with the increase of Fluc-circRNA transfection dose. Western blot analysis showed that HA protein was successfully expressed in HEK-293T cells transfected with HA-circRNA.Conclusion In this study,linear RNA was successfully cyclized in vitro and different proteins were expressed,which lays a foundation of the research of new influenza vaccines and mRNA vaccines.
ABSTRACT
Objective To observe conditioned enhancement of antibody production against influenza vaccine. Methods 36 female BALB/c mice were injected with 3 μg/mouse influenza virus hemagglutinin (HA) as the unconditioned stimulus (UCS),and camphor odor was served as the conditioned stimulus (CS). After a CS/UCS pairing was made,animals were re-exposed to the CS at Weeks 6. Results Through one conditioned stimulus,the optical density of anti-HA antibody of the conditioned group (Weeks 9:0.68±0.06; Weeks 10:0.60±0.06)was significantly increased compared with the unconditioned group (Weeks 9:0.53±0.06; Weeks 10:0.48±0.04) ( P <0.01). The level of anti-HA antibody of the conditioned group was also significantly greater than other controlled groups( P <0.05). Conclusion Through a single exposure to camphor odor which was paired with immunization of influenza virus HA in a single trial learning protocol,a significant conditioned anti-HA IgG production occurred.