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That means scientists can actually see where individual hydrogen atoms are positioned in the protein's core, providing clues as to which atoms are participating in key stabilizing interactions.

Doctors often use infusions of antibodies to bolster immune systems weakened by cancer or other conditions, but ironically, these proteins are susceptible to enzymes that break them down. A number of such monoclonal antibody-based drugs are in clinical use, such as Herceptin for breast cancer or Avastin for colorectal cancer.

The lancelet's immune response proteins, however, are resilient. Understanding their essential architecture with such precision could lead to new, improved types of antibody-based therapies that are better able to persist in the body, Ostrov said.

"If we could take advantage of the atomic level structural features that we see, particularly those structural features at the stable core of this molecule, then we expect to design and produce more stable monoclonal antibodies for therapy," he said.

Neil S. Greenspan, M.D., Ph.D., a professor of pathology at Case Western Reserve University School of Medicine, called the study "captivating and thorough."

"However, I expect that further research will be required to corroborate some of the key evolutionary interpretations and to place this study in fuller perspective," Greenspan said. "Should the authors' views prove to be basically correct, the study would offer the prospect of enhancing our understanding of the structural requirements for molecules used by the adaptive immune response to recognize and counter components of invading microbes. If so, it would provide an illustration of the potential for studies of diverse species, even those that at first glance may appear to be of no special interest, to yield information of value in understanding human physiology and of use in facilitating medical advances."