Research Roundup: Cow antibodies, Zika’s impact on male fertility, and hepatitis C research
The North Dakota–based SAB Biotherapeutics, Inc. has devised a way to elicit the production of human, disease-fighting antibodies in cows. Antibodies, which are produced by the immune system in response to an infection, recognize and eliminate specific pathogens. Antibodies have long been used in medicine: in the recent Ebola outbreak, antibodies from survivors were used to treat new patients. While humans can only produce 4 liters of antibodies per month—enough to treat three patients—cows produce 30 to 60 liters per month. Researchers have tried to use several mammals to produce antibodies for use in humans, but the immune system sees animal antibodies as foreign, resulting in an allergic reaction. Now, the team at SAB Biotherapeutics has designed a strategy in which cows’ antibody-producing genes are replaced with human genes. Consequently, when a cow is infected with a pathogen, it produces human antibodies in response. The company is currently testing the technology, evaluating its ability to produce antibodies against Middle East Respiratory Syndrome (MERS). While it may not be available for three to five years, the World Health Organization has already recognized the platform as one of the six most promising approaches for pandemic preparedness.
The Zika virus has made headlines for its devastating impact on fetal development, and the global response has consequently focused on women who are or may become pregnant. However, new research suggests that the virus may not be so mild in men. In humans, the virus can remain in semen for up to six months, and a recent study in mice reveals that the continued presence of the virus can damage cells that are critical to reproduction. The research team at Washington University in St. Louis, Missouri, infected male mice with Zika, and within three weeks, their testes shrunk to one-tenth their original size; the seminiferous tubules—critical to producing new sperm—were damaged; and the Sertoli cells—involved in sperm growth—were dwindling in number. Ultimately, infected mice had lower sperm counts and sex hormones and were only able to impregnate a fraction of the female mice compared to their healthy counterparts. Further research is needed to determine whether Zika has the same impact on the reproductive system and fertility of human males.
New drugs have made hepatitis C curable, but researchers continue to hunt for a preventative vaccine since treatment is prohibitively expensive for many patients and the virus often causes irreparable liver damage by the time of diagnosis. One protein on the surface of the virus—E2—has been a target for many vaccine candidates, however, despite its ability to induce an immune response, the protein has not successfully protected against the virus in either animal or human trials. By precisely mapping and analyzing the structure of E2, scientists at The Scripps Research Institute have discovered that E2 is an unusually flexible protein. As E2 morphs, the immune system produces an assortment of antibodies to match its dynamic shape, many of which are ineffective against the virus. Now, the team is engineering a synthetic, stable version of E2 that will generate a batch of similar, highly-effective antibodies to protect against infection.