{'fraction_non_alphanumeric': 0.026781202627589692, 'fraction_numerical': 0.021728145528044467, 'mean_word_length': 5.827586206896552, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Mosquito Cells Infected with Japanese Encephalitis Virus Release Slowly‐Sedimenting Hemagglutinin Particles in Association with Intracellular Formation of Smooth Membrane Structures

Arthropod‐borne flaviviruses can grow in both arthropod and mammalian cells. Virion morphogenesis, though well studied in mammalian cells, is still unclear in arthropod cells. Here, we compared a mosquito cell line C6/36 and a mammalian cell line Vero in extracellular virus particles and intracellular ultrastructures triggered by infection with Japanese encephalitis virus (JEV). Sedimentation analyses of virion and slowly‐sedimenting hemagglutinin (SHA) particles released by infection with the Nakayama strain revealed that C6/36 cells produced higher envelope (E) antigen levels in the SHA than the virion fraction in contrast to Vero cells that showed the opposite pattern. Specific infectivities per ng of E were similar in both cells, whereas specific hemagglutinating activities in the SHA fraction were lower in C6/36 than Vero cells. The precursor membrane protein was less efficiently cleaved to the membrane protein in SHA particles released from C6/36 than Vero cells. Ultrastructural studies showed more remarkable production of smooth membrane structures (SMSs) in C6/36 than in Vero cells. The differences in sedimentation patterns of extracellular virus particles between Nakayama‐infected C6/36 and Vero cells were consistently observed in 5 other strains (Beijing P1, Beijing P3, JaTH‐160, KE‐093 and JaGAr‐O1), except for KE‐093‐infected C6/36 cells which exhibited the Vero‐type sedimentation profile under conditions of open cultivation. By electron microscopy, the production of SMSs from KE‐093‐infected C6/36 cells under open conditions was markedly less than that under closed conditions where the cells exhibited the C6/36‐type sedimentation profile. Thus, intracellular SMS formations were associated with extracellular SHA production in JEV‐infected mosquito cells.