Emergex Vaccines Holding Limited has formulated and confirmed the synthesis and assembly of a CD8+ T cell adaptive vaccine for smallpox and monkeypox, made up predominantly of early “eclipse phase” antigens.
The monkeypox virus is part of the same family of double-stranded DNA viruses (Poxviridae) as variola virus, the virus that causes smallpox; they share many highly conserved proteins that make ideal T cell vaccine targets.
Emergex’s current formulation of the vaccine contains 20 viral peptides binding a range of human leukocyte antigens (HLA) that can present to CD8+ T cells to recognize and destroy viral-infected cells. The fact that the vaccine construct’s pathogen peptides come from the “eclipse phase” of viral replication plays a key role in infection kinetics.
The “eclipse phase” is defined as the period between the entry of the virus’ genetic material into the host cell, causing infection, and the appearance of new mature virus in a host cell. Emergex’s vaccine construct primes T cells to target an infected cell, with an ideal outcome being an “abortive infection”. This is one mechanism of sterilizing immunity; however, vaccine-induced immunity can protect against future infection in the absence of sterilizing immunity.
Responding rapidly
The vaccine construct has been synthesized to preclinical grade at Emergex’s in-house GMP manufacturing facility near Oxford, U.K., with preclinical testing being performed in the laboratories at Emergex USA.
Phillip Williams, chief scientific officer at Emergex, said: “We’re very proud to have synthesized this smallpox and monkeypox vaccine so quickly using intelligence and resources to target highly conserved sequences shared by both viruses. This accomplishment demonstrates our ability to respond rapidly to emerging disease threats by creating experimental vaccines using our highly adaptable plug-and-play technology.”
Thomas Rademacher, co-founder and CEO at Emergex, added: “The recent global monkeypox outbreak and global shortages of smallpox vaccines highlight the urgent need for societies worldwide to be well prepared in advance of any future disease outbreaks. Our vaccine, which targets highly conserved antigens, is designed to be cross-reactive and convey protection from both smallpox and monkeypox viruses and may also confer protection against other members of the pox family.”
Smallpox and monkeypox
Smallpox is an acute contagious disease caused by the variola virus, thought to have originated up to 3,000 years ago. It was a devastating disease that caused millions of deaths before the World Health Organization declared that it had been eradicated in 1980.
It was widely considered an international public health triumph demonstrating the power of vaccines. Among survivors, the disease often left permanent and debilitating complications, such as severe scarring or blindness. With a fatality rate of more than 30% in unvaccinated people, there are concerns smallpox could pose a future biosecurity threat.
Monkeypox is a zoonotic disease primarily dominant in tropical rainforest areas in Central and Western Africa. It can be transmitted between people through close contact with body fluids, respiratory droplets, and contaminated materials. Over the last 10 months, 68,900 laboratory-confirmed cases of monkeypox and 25 deaths have been reported from 106 countries worldwide. It is the first time monkeypox has spread widely outside Central and West Africa.