Natural killer cell responses to emerging viruses of zoonotic origin
Autor
Diaz-Salazar, Carlos
Sun, Joseph C
Institución
Resumen
Emerging viral diseases pose an ongoing threat to mankind, especially in a globalized and highly interconnected
world. A prime example of such a threat is the current
COVID-19 pandemic, with more than eighteen million
confirmed cases and over 680 000 deaths worldwide at the
time of this publication [1]. All of the diseases with the
greatest potential to cause a public health emergency, as
identified by the World Health Organization, are driven
by viruses of zoonotic origin [2]. These include viruses
that cause haemorrhagic fever (e.g. Ebola, Marburg,
Dengue, and Lassa viruses), highly pathogenic respiratory coronaviruses (e.g. those causing MERS and SARS),
and other viruses (e.g. Nipah, Zika, and Chikungunya).
These zoonotic viruses are extremely diverse in nature, as
some are transmitted through vectors such as mosquitoes
or ticks (e.g. Dengue, Tick-borne encephalitis), whereas
human-to-human is the main mode of transmission for
others (e.g. Ebola, SARS-Cov2). Some zoonotic viruses
have a wide range of natural hosts (e.g. Huaiyangshan,
West Nile), whereas others are restricted to specific
species such as bats (e.g. Marburg, Nipah) (Table 1).
However, most zoonotic viruses have shared characteristics, such as being single-stranded RNA (ssRNA)
viruses, and causing mild or asymptomatic infections in
its natural host animal, while provoking profound pathologies in humans [3 ]. Understanding the immune mechanisms that allow animal reservoirs to tolerate these
viruses will shed light into how viral zoonotic infections
progress to severe illness in humans. This review
describes the role of Natural killer (NK) cells, a critical
component of early antiviral immunity, in the establishment of tolerance to viral infections in natural hosts, as
well as their role in the development of disease in nonnatural hosts.