The World Health Organization (WHO) declared the 2022 monkeypox outbreak a Public Health Emergency of International Concern (PHEIC) on 23 July 2022 local time . On July 27, the WHO reported more than 18,000 cases of monkeypox in 78 countries and territories, mostly in Europe and the Americas. This is the first time that the monkeypox virus has spread widely outside of Central and West Africa in multiple non-endemic countries with human-to-human transmission. The serological and immunological detection of key target antigens and antibodies of the monkeypox virus, the study of the monkeypox virus infection mechanism, the research and development of drugs and vaccines, and the treatment and prevention of monkeypox are all dependent on neutral antibodies with bioactivity and recombinant monkeypox proteins developed by bioengineering technology.
In order to help scientists and vaccine research and development institutions better deal with the monkeypox virus, CUSABIO has developed several recombinant monkeypox virus proteins based on the published gene sequences of the monkeypox virus. All of these recombinant monkeypox virus proteins are expressed in multiple expression systems, including the eukaryotic expression system. The structure of the yeast-expressed proteins is closer to that of the native proteins. They undergo strict quality control and their purity is measured by SDS-PAGE, >85%.
Among these recombinant monkeypox virus antigens, A30L acts as an envelope protein required for virus entry into the host and cell-cell fusion and is considered to be an important target in monkeypox virus research. A42R is currently the only entry for a monkeypox protein. E8L is an important gene for virus invasion into host cells. As the cell surface binding protein of MV, E8L binds to the chondroitin sulfate, allowing virions to attach to target cells during the viral invasion and replication. These recombinant monkeypox virus proteins can be used as tools for basic research of monkeypox virus, the development of monkeypox virus neutralizing antibody, as well as the quality control of preventive vaccines and therapeutic drugs.
In addition, CUSABIO also provides several recombinant proteins involved the interaction between the monkeypox virus and host.
Monkeypox is a zoonotic infectious disease, the symptoms of which are similar but not as severe as smallpox. Symptoms usually last 2 to 4 weeks. Early symptoms of monkeypox infection include fever, headache, muscle pain, swollen lymph nodes, chills, and tiredness, followed by a blister-like rash that heals  . Since monkeypox is a self-limiting disease, most persons can recover in 2 to 4 weeks. Monkeypox has a fatality rate of about 1% to 10%, with the highest proportion of deaths occurring in children.
Monkeypox is caused by the monkeypox virus (MPXV). Structurally, the monkeypox virus is an enveloped double-stranded DNA virus belonging to the orthopoxvirus genus of the poxviridae family . Poxviruses exist in two forms: mature virions (MV), and extracellular enveloped virions (EV). MV is comprised of a viral core component containing double-stranded DNA, a protein side body, and an outer membrane consisting of 20 viral proteins. MV is very stable and mediates the transmission between hosts, whereas EV has a fragile outer membrane and mediates transmission between cells of the same host. Monkeypox virus enters the body from the respiratory mucosa, propagates in lymphocytes, invades the blood to produce transient venereemia, and then propagates in cells, invades the blood from cells to replicate to the skin of the whole body, ultimately causing lesions.
The virus sequencing results of partial cases in non-endemic countries showed the monkeypox virus is the West African clade, which has a lower fatality rate than another subbranch-the Congo Basin clade. The monkeypox virus is not only raised in monkeys. Many rodents carry the virus, including African squirrels, tree squirrels, Gambian kangaroos, dormouse, etc. Monkeypox virus can be transmitted from animals to humans and humans to humans. It is mostly internally transmitted among humans through large respiratory droplets, direct contact with skin lesions, and possibly through contaminated fomites .
Currently, there is no specific treatment for monkeypox. Clinically, the treatment principle is symptomatic support treatment, control of complications, and prevention of sequelae . An outbreak can be controlled by preventing the monkeypox virus infection. Physical isolation is the most effective way to stop the spread of the monkeypox virus. WHO data shows that the efficacy of the smallpox vaccine against the monkeypox virus is as high as 85%, which is derived from the cross-protective effect of antibodies.
 Multi-country monkeypox outbreak: situation update [J]. World Health Organization, June 27, 2022.
 Bunge EM, Hoet B, Chen L, et al. The changing epidemiology of human monkeypox - a potential threat [J]? A systematic review. PLoS Negl Trop Dis 2022;16(2):e0010141-e0010141.
 Monkeypox. World Health Organization, May 19, 2022.
 Shchelkunov, S. N., Marennikova, et al. Orthopoxviruses Pathogenic for Humans 155–192 (Springer, 2005).
 Monkeypox: background information. UK Health Security Agency, 2018.
 Disease Outbreak News; Multi-country monkeypox outbreak in non-endemic countries: World Health Organization, 2022.