Generation of a bovine cell line for gene engineering using an HIV-1-based lentiviral vector.

Human immunodeficiency virus type 1 (HIV-1)-based lentiviral vectors are indispensable tools for gene engineering in mammalian cells. Conversely, lentiviral vector transduction is severely inhibited in bovine cells. Previous studies demonstrated that this inhibition is caused by the anti-lentiviral host factor tripartite motif containing 5 (TRIM5), which targets incoming HIV-1 virions by interacting with the viral capsid. In this study, we investigated several methods for overcoming the limited applicability of lentiviral vectors in bovine cells. First, we demonstrated that the SPRY domain of bovine TRIM5 is the major determinant of anti-viral activity. Second, we found that mutations that allow the capsid to evade rhesus macaque TRIM5α minimally rescued HIV-1 infectivity in bovine-derived MDBK cells. Third, we found that cyclosporine A, which relieves the inhibition of HIV-1 infection in monkey cells, significantly rescued the impaired HIV-1 infectivity in MDBK cells. Lastly, we successfully generated a bovine cell line lacking intact TRIM5 using the CRISPR/Cas9 technique. This TRIM5 knockout cell line displayed significantly higher susceptibility to an HIV-1-based lentiviral vector. In conclusion, our findings provide a promising gene engineering strategy for bovine cells, thereby contributing to innovations in agriculture and improvements in animal health.

The SARS-CoV-2 Lambda variant exhibits enhanced infectivity and immune resistance.

SARS-CoV-2 Lambda, a variant of interest, has spread in some South American countries; however, its virological features and evolutionary traits remain unclear. In this study, we use pseudoviruses and reveal that the spike protein of the Lambda variant is more infectious than that of other variants due to the T76I and L452Q mutations. The RSYLTPGD246-253N mutation, a unique 7-amino acid deletion in the N-terminal domain of the Lambda spike protein, is responsible for evasion from neutralizing antibodies and further augments antibody-mediated enhancement of infection. Although this mutation generates a nascent N-linked glycosylation site, the additional N-linked glycan is dispensable for the virological property conferred by this mutation. Since the Lambda variant has dominantly spread according to the increasing frequency of the isolates harboring the RSYLTPGD246-253N mutation, our data suggest that the RSYLTPGD246-253N mutation is closely associated with the substantial spread of the Lambda variant in South America.