Scientists Learn How Poxviruses Defeat the Body's Host Defense
Smallpox virus, which killed millions of humans through the ages, ranks among the world's most feared bioterrorism agents. In a new report, virologists from the School of Medicine at The University of Texas Health Science Center at San Antonio and their collaborators at Oklahoma State University demonstrate how poxviruses such as smallpox defeat the body's host immune defenses. The implications extend beyond viral infections to cancer therapy, says senior author Yan Xiang, PhD, associate professor in the Department of Microbiology and Immunology, UT Health Science Center.
Smallpox virus magnified approximately 370,000 times. Smallpox, which killed millions of humans through the ages, ranks among the world's most feared bioterrorism agents. In a new report, virologists from the School of Medicine at the University of Texas Health Science Center at San Antonio and collaborators at Oklahoma State University demonstrate how poxviruses such as smallpox defeat the body's host immune defenses.
Courtesy of CDC/Dr. Fred Murphy, Sylvia Whitfield
Smallpox virus, which killed millions of humans through the ages, ranks among the world's most feared bioterrorism agents. In a new report, virologists from the School of Medicine at The University of Texas Health Science Center at San Antonio and their collaborators at Oklahoma State University demonstrate how poxviruses such as smallpox defeat the body's host immune defenses. The implications extend beyond viral infections to cancer therapy, says senior author Yan Xiang, PhD, associate professor in the Department of Microbiology and Immunology, UT Health Science Center.
Xiang and colleagues revealed how a molecule on the poxviruses defeats a host restriction factor called SAMD9 in humans and animals. In addition to protecting against viruses, SAMD9 suppresses tumors, and mutations in the human SAMD9 gene are responsible for a life-threatening cancer called normophosphatemic familiar tumoral calcinosis. SAMD9 is also implicated in myeloid leukemias and lung cancer.
"There is an 'arms race' occurring between pathogens (disease-causing agents) and their hosts," Dr. Xiang said. "To survive in their hosts, many pathogens utilize specific inhibitors of the host restriction factors. SAMD9 is an evolutionally conserved immune barrier, but it has been successfully overcome by diverse poxviruses." First author of the study is Xiangzhi Meng, Ph.D., an assistant professor in microbiology and immunology at the Health Science Center.
The discovery was described in December in Proceedings of the National Academy of Sciences.
Source: University of Texas Health Science Center at San Antonio
CDC Urges Vigilance: New Recommendations for Monitoring and Testing H5N1 Exposures
July 11th 2025With avian influenza A(H5N1) infections surfacing in both animals and humans, the CDC has issued updated guidance calling for aggressive monitoring and targeted testing to contain the virus and protect public health.
IP LifeLine: Layoffs and the Evolving Job Market Landscape for Infection Preventionists
July 11th 2025Infection preventionists, once hailed as indispensable during the pandemic, now face a sobering reality: budget pressures, hiring freezes, and layoffs are reshaping the field, leaving many IPs worried about their future and questioning their value within health care organizations.
A Helping Hand: Innovative Approaches to Expanding Hand Hygiene Programs in Acute Care Settings
July 9th 2025Who knew candy, UV lights, and a college kid in scrubs could double hand hygiene adherence? A Pennsylvania hospital’s creative shake-up of its infection prevention program shows that sometimes it takes more than soap to get hands clean—and keep them that way.
