Why Typhoid Fever Is Human Specific: Dr. Ajit Varki and Coworkers Discover One Explanation

Typhoid Mary, Not Typhoid Mouse: Lack of enzyme explains why typhoid fever is a human-specific disease

The bacterium Salmonella Typhi causes typhoid fever in humans, but leaves other mammals unaffected.  Researchers at University of California, San Diego and Yale University Schools of Medicine now offer one explanation — CMAH, an enzyme that humans lack. Without this enzyme, a toxin deployed by the bacteria is much better able to bind and enter human cells, making us sick. The study is published in the Dec. 4 issue of Cell.

In most mammals (including our closest evolutionary cousins, the great apes), the CMAH enzyme reconfigures the sugar molecules found on these animals’ cell surfaces into a form that the typhoid toxin cannot bind. Humans don’t produce CMAH, meaning our cell surface sugars are left unchanged — and as this study shows, in a state just right for typhoid toxin attachment.

“We started this project looking at something completely different in relation to cancer, but serendipity instead helped us solve the mystery of what the typhoid toxin binds,” said co-senior author Ajit Varki, MD, Distinguished Professor in the Departments of Medicine and Cellular and Molecular Medicine at UC San Diego. “That’s the beauty of basic research — though we didn’t set out with the intent, these findings may now spur the development of new therapies for typhoid fever.” Varki co-directed the study with Jorge E. Galán, PhD, DVM, professor and department chair at Yale University School of Medicine. … Read the full story from the UC San Diego Newsroom

Glycans Enter Mainstream of Biomedical Science

UC San Diego leads new national program to further develop the science of glycobiology

Scientists at the University of California, San Diego School of Medicine have received a major 7-year, $18 million grant to begin translating emerging discoveries in the field of glycosciences into new discoveries and therapies related to heart, lung and blood diseases…. Read the full story from the UCSD Newsroom

Dr. Ajit Varki

Principal investigator and project leader Ajit Varki, MD, is Distinguished Professor of Medicine and Cellular and Molecular Medicine, Co-Director of the Glycobiology Research and Training Center, and Co-Director of the UCSD/Salk Center for Academic Research and Training in Anthropogeny. | Read the project abstract

A Cancer Marker and Treatment in One?

UC San Diego Researchers Find Promise in Non-Human Sialic Acid Antibodies

Researchers at the University of California, San Diego School of Medicine say antibodies to a non-human sugar molecule commonly found in people may be useful as a future biomarker for predicting cancer risk, for diagnosing cancer cases early and, in sufficient concentration, used as a treatment for suppressing tumor growth…. Read the full story from the UCSD Newsroom

Dr. Richard Schwab and Dr. Ajit Varki (pictured above left), led the study, which was a multicenter collaboration that included the departments of Medicine and of Cellular and Molecular Medicine, Moores Cancer Center, and the Glycobiology Research and Training Center at UC San Diego.

Richard Schwab, MD, is Assistant Professor of Medicine in the Division of Hematology-Oncology. Ajit Varki, MD, is Distinguished Professor of Medicine and Cellular and Molecular Medicine, Co-Director of the Glycobiology Research and Training Center, and Co-Director of the UCSD/Salk Center for Academic Research and Training in Anthropogeny. Read the abstract of the published study in Cancer Research.

Non-human Sugar in Biotech Drugs Causes Inflammation

New research findings from Dr. Ajit Varki and colleagues are the subject of the UCSD Newsroom story, “Non-human Sugar in Biotech Drugs Causes Inflammation.”

Ajit Varki, M.D., is Professor of Medicine in the Division of Hematology-Oncology and Professor in the Department of Cellular and Molecular Medicine. He co-directs the UC San Diego Glycobiology Research and Training Center and the UC San Diego/Salk Center for Academic Research and Training in Anthropogeny (CARTA). He is Associate Dean of the Physician-Scientist Training Program.

In the Media: Dr. Ajit Varki

Dr. Ajit Varki is one of a team of researchers whose recent study is described in the Wired article, “Rare Gene Glitch a Clue to Genomics Mystery.”

Ajit Varki, M.D., is Professor of Medicine in the Division of Hematology-Oncology and Professor in the Department of Cellular and Molecular Medicine. He co-directs the UC San Diego Glycobiology Research and Training Center and the UC San Diego/Salk Center for Academic Research and Training in Anthropogeny (CARTA). He is Associate Dean of the Physician-Scientist Training Program.

In the Media: Dr. Ajit Varki

The UC San Diego/Salk Center for Academic Research and Training in Anthropogeny (CARTA) and its co-director, Dr. Ajit Varki, are featured in the story, “Cutting to the Bone Of Human Origins,” in Science.

Ajit Varki, M.D., is Professor of Medicine in the Division of Hematology-Oncology and Professor in the Department of Cellular and Molecular Medicine. He co-directs the UC San Diego Glycobiology Research and Training Center and is Associate Dean of the Physician-Scientist Training Program.