Human Anti-Monkeypox Virus Monoclonal antibody, clone 6D8

Monkeypox virus (mpox) belongs to the genus Orthopoxvirus, which can lead to a zoonotic infection called monkeypox. It has similar genetic structure to smallpox virus. There are only four members of the Orthopoxviruses that infect humans: smallpox virus, cowpox virus, varicella virus and monkeypox virus, each encoding soluble antigens, nucleoprotein antigens and erythrocyte agglutinins (essentially identical antigens), and they are all cross-immune to each other.

Monkeypox virus is morphologically identical to Orthopoxvirus, with a 30 nm peripheral outer membrane. The internal genome is a double-stranded DNA, approximately 197 kb in length, and the genome ends contain an identical but directionally opposite terminal inverted repeat sequence. The virus contains multiple open reading frames, four of which are located in terminal inverted repeat sequences. The genomic GC content is very low, containing about 33%. The genome contains most of the enzymes that the virus needs to reproduce, and the virus can replicate by itself. Gene-wise, there are two major evolutionary clades of monkeypox virus: Central African (Clade I) and West African (Clade II). Case fatality rate for the Central African section is around 10% and for the West African section is about 3.6%. Global epidemic now ruled by West African Clade IIb branch, growing much faster, and may be spreading the disease.

Figure 1. Schematic representation of MPXV virion structure
(Source: Harapan H, et al. 2022)

Monkeypox mostly spreads by contact with infected animals or people, the most common sources being rodents and non-human primates such as monkeys. Transmission between humans usually involves touching infected skin lesions, body fluids or respiratory droplets from another person. Infection can also be transmitted through the contact with contaminated materials. Monkeypox incubates between 5 and 21 days. Monkeypox is 5-21 days incubated. Symptoms may arise from then on: fever, headache, muscle pains, enlarged lymph nodes. Rake generally grows on the face, and then all over the body – blistering, pustules, crusting on and crusting off. This takes 2–4 weeks. There is no monkeypox vaccine, but there is an 85 per cent protection from the smallpox vaccine because they look the same. The treatment consists of supportive care such as treating the rash, hydration and pain management. While some antiviral drugs have had success in animal models, they have yet to be tested on humans in a large-scale clinical trial.

Anti-Mpox Monoclonal antibody
Anti-MPXV Monoclonal antibody