Recombinant Monkeypox (Zaire79) A35R

Monkeypox virus (MPXV) is a zoonotic member of the Orthopoxvirus genus in the Poxviridae family¹. Monkeypox has gained clinical relevance due to the eradication of smallpox^1,2. Loss of immunity to smallpox in human populations, via infection or vaccination, has created opportunities for increased monkeypox prevalence and viral mutations that may affect virulence^1,2. An infection with one orthopoxvirus of any one species, or vaccinia virus (VACV) vaccination, protects against infection by other orthopoxviruses^3,4,5. MPXV is an enveloped virus with a linear, double-stranded DNA genome² and a large, complex proteome of over 200 proteins⁶. During infection, the virus exists in two antigenically distinct forms: mature virions (MV) or enveloped virions (EV)⁶.

A35R is an ortholog of VACV A33R, which encodes a type II integral membrane protein present as a dimer on EV⁷. A33R is a target of immunotherapeutics and has been identified as a protective target of subunit vaccines delivered as DNA or protein. Antibodies against A33R, such as monoclonal antibody MAb-1G10, which protects animals from lethal challenge with VACV strain WR, are protective in vivo⁸. However, MAb-1G10 binds poorly to recombinant A35R in radiolabeled immunoprecipitation analysis and ELISA assays as well as to authentic A35R protein expressed in MPXV-infected cells, unless mutated to match the VACV peptide at positions 117, 118, and 120⁷. S118L and E120S substitutions and double changes at K117Q/S118L and S118L/E120S can also rescue MAb-1G10 interaction with A35R. Additionally, MAb-1G10 can interact with other A33 orthopoxvirus orthologs that are identical to VACV at amino acids 118 and 120, demonstrating a critical role for these amino acids in MAb-1G10 binding. Furthermore, serum antibodies from mice vaccinated with A33R (VACV) DNA improved when positions 117, 118, and 120 of A35R (MPXV) were changed to those of A33R, indicating a role in protective immunity for this region of A33.

There are eight amino acid substitutions between the A33R (VACV) and A35R (MPXV) orthologs⁷. Additionally, A35R (MPXV) is truncated by four amino acids at the carboxy terminus. Binding to MAb-1G10 is not rescued by changes to the carboxy terminus.

Viral

NP_536572.1

RLNQCMSANEAAITDSAVAVAAASSTHRKVASSTTQYDHKESCNGLYYQG SCYILHSDYKSFEDAKANCAAESSTLPNKSDVLTTWLIDYVEDTWGSDGNP ITKTTSDYQDSDVSQEVRKYFCT

NP

Lyophilized

14 kDa

This lyophilized protein is stable for twelve months when stored at -20°C to -70°C. After aseptic reconstitution, this protein may be stored for one month at 2°C to 8°C or for three months at -20°C to -70°C in a manual defrost freezer. Avoid Repeated Freeze Thaw Cycles.

Ambient

Viral

Research Use Only

1 Sklenovská N, Van Ranst M. Front Public Health. 6:241. 2018.
2 Moore M, Zahra F. 2021 Oct 19. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan–.
3 McConnell S, Herman YF, Mattson DE, et al. Am J Vet Res. 25:192-195. 1964.
4 Hammarlund E, Lewis MW, Carter SV, et al. Nat Med. 11(9):1005-1011. 2005.
5 Gilchuk I, Gilchuk P, Sapparapu G, et al. Cell. 167(3):684-694.e9. 2016.
6 Moss B. Immunol Rev. 239:8–26. 2011.
7 Golden JW, Hooper JW. Virology. 377(1):19-29. 2008.
8 Lustig S, Fogg C, Whitbeck JC, et al. J. Virol. 79(21):13454–13462. 2005.