Growth characteristics of Rickettsia species LON strains closely related to Rickettsia japonica isolated from Haemaphysalis longicornis ticks in mouse-derived L929 and human-derived THP-1 host cell lines.

In this study, microscopic analysis showed that LONs in a mouse-derived L929 host cell line are rod shaped with sizes of 0.3-0.5 x 0.5- 2.0 μm. Molecular-based analysis revealed the existence of LON-specific disrupted open reading frame in R. japonica-related group specific DNA region. Growth kinetics of LON-2 and LON-13 strains analyzed by a quantitative real-time PCR showed 100-fold increment or more of LONs cultured in L929 host cells at 30oC and slightly less increment at 33oC, and 25-fold increment in human-derived THP-1 host cells at 35oC on day 7 (168 h) post infection. The generation times of 2 LON strains cultured in L929 and THP-1 were estimated to be 9.4-12.9 h and 9.6-10.9 h, respectively. As far as we know, this is for the first time a report regarding the biological characteristics of Rickettsia sp. LONs in mammalian cells and will provide the significant information for the experimental approaches of the other rickettsiae. PMID: 32863353 [PubMed - as supplied by publisher]
Source: Japanese Journal of Infectious Diseases - Category: Infectious Diseases Authors: Tags: Jpn J Infect Dis Source Type: research