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bioRxiv · 10.1101/2024.10.22.619692

Engineered protein destabilization reverses intrinsic immune evasion for candidate vaccine pan-strain KSHV and SARS-CoV-2 antigens

Wan, L.·Xie, B.·Shuda, M.·Delgoffe, G. M.·Chang, Y.·Moore, P. S.
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Abstract

Both Kaposi sarcoma herpesvirus LANA and SARS coronavirus 2 RdRp/nsp12 are highly conserved replication proteins that evade immune processing. By deleting the LANA central repeat 1 domain (LANA{Delta}CR1) or by dividing RdRp into two separated fragments (RdRpFrag) to maximize nascent protein mis-folding, cis peptide presentation was increased. Native LANA or RdRp SIINFEKL fusion proteins expressed in MC38 cancer cells were not recognized by activated OT-1 CD8+ cells against SIINFEKL but cytotoxic recognition was restored by expression of the corresponding modified proteins. Immunocompetent syngeneic mice injected with LANA- or RdRp-SIINFEKL MC38 cells developed rapidly-growing tumors with short median survival times. Mice injected with LANA{Delta}CR1- or RdRpFrag-SIINFEKL had partial tumor regression, slower tumor growth, longer median survival, as well as increased effector-specific tumor-infiltrating lymphocytes. These mice developed robust T cell responses lasting at least 90 days post-injection that recognized native viral protein epitopes. Engineered vaccine candidate antigens can unmask virus-specific CTL responses that are typically suppressed during native viral infection.

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Wan, L., Xie, B., Shuda, M., Delgoffe, G. M., Chang, Y., Moore, P. S.. 2024-10-22. Engineered protein destabilization reverses intrinsic immune evasion for candidate vaccine pan-strain KSHV and SARS-CoV-2 antigens. https://doi.org/10.1101/2024.10.22.619692

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