Comparing the Hepato-Neuropathology of Parental Recombinant & Proline Mutant Strains of MHV Inoculated at 1000 PFU in C57BL/6 Mice

Mohammed, Nahaf A (2023) Comparing the Hepato-Neuropathology of Parental Recombinant & Proline Mutant Strains of MHV Inoculated at 1000 PFU in C57BL/6 Mice. Masters thesis, Indian Institute of Science Education and Research Kolkata.

Text (MS dissertation of Mohammed Nahaf A (18MS142)) Thesis_18MS142.pdf - Submitted Version Restricted to Repository staff only Download (2MB)

Abstract

Mouse Hepatitis virus (MHV) can cause meningitis, hepatitis, encephalitis, optic neuritis, myelitis with subsequent axonal loss and demyelination upon infection in mice, which mimics certain pathological features of human neurological disease multiple sclerosis (MS). Prior studies conducted with the parental recombinant strains RSA59 PP and RSMHV2 P showed that the spike (S) protein (host attachment protein) is one of the major genomic determinants of pathogenic properties and viral spread from the brain to the spinal cord as well as from grey to white matter and causes myelin loss and axonal degeneration. The fusion peptide (FP) in the S-protein is the key player that mediates intercellular viral spread. The proline residue in the FP of many viruses has been suggested to be important by mutational studies. The FP of RSA59 PP have two central consecutive prolines, whereas RSMHV2 P has only a single proline in its FP. To identify the distinct role of central proline in FP, generated two proline mutant strains, RSA59 P by deletion of one of the two prolines and RSMHV2 PP by addition of a proline near the existing single proline. Studies found that two consecutive prolines in FP promote a more ordered, compact, and rigid structure in the spike protein. These effects on FP structure were due to proline’s unique stereochemical properties intrinsic to its secondary amino acid structure, revealed by molecular dynamics and NMR experiments. The previous studies on these viruses were based on half of the LD50 (Lethal Dose 50) dose, which is 20000 PFU (Plaque-Forming Unit) for RSA59 PP, also 20000 PFU probably for RSA59 P and RSMHV2 PP, whereas it is 100 PFU for RSMHV2 P. This study compares the Hepato-Neuropathology of parental recombinant and proline mutant strains at 1000 PFU for all four virus strains. Significant differences were observed in comparing double and single proline strains in the brain and liver. Also, the viral spread and inflammation in the spinal cord were analyzed.

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