Enzo Biochem Research Team Develops Mouse with Human Liver Cells for Hepatitis Research.

FARMINGDALE, N.Y.--(BUSINESS WIRE)--May 18, 1998--Enzo Therapeutics, Inc. a wholly owned subsidiary of Enzo Biochem, Inc. (ASE:ENZ) today reported that its scientists, working with researchers at the Liver Center at the Albert Einstein College of Medicine in New York, have succeeded in developing mice hosting functional human liver cells that can support the growth of hepatitis B virus.

This is the first time this type of animal model system capable of supporting the growth of hepatitis B virus in human hepatocytes has been reported. These experimental mice can function as an animal model system for evaluating new therapeutic modalities to treat hepatitis B.

The report was presented on Sunday by Jennifer J. Brown, Ph.D., a research scientist in Dr. J. Roy Chowdhury's laboratory at Albert Einstein, to the attendees of the annual meeting of the American Association of Gastroenterology in New Orleans.

Until now, hepatitis research has been hampered by a lack of viable animal models capable of supporting the infection and replication of the virus in human hepatic cells in vivo.

"This animal model system, which can mimic hepatitis infection in humans, will enable us to examine a variety of therapeutic approaches for treating hepatitis, including genetic antisense," noted Dr. Brown. "HBV has a very narrow host specificity, and infects only a few non-human primates in addition to humans. Using these Enzo-developed techniques, we were able to successfully transplant human hepatocytes into immune deficient Rag II mutant mice which in turn were able to support the infection and growth of HBV in vivo."

"This is a very significant development which can now facilitate the systematic evaluation of gene therapy and other novel treatment modalities for HBV infection, an active area of research and development at Enzo," said Dean L. Engelhardt, Ph.D., Senior Vice President at Enzo Therapeutics. "It also has broader applicability in the study of other human cell-specific viral infections."

Dr. Brown further reported the development of a hepatitis B virus cell line made by cloning immortalized human hepatocytes stably transfected with the complete HBV genome. After transplantation into the Rag II mutant mice, these engrafted cells, containing the HBV virus DNA, are capable of producing viral particles.

"The novel therapeutic approaches for illnesses, such as HBV, Enzo is developing at times necessitates developments in the research labs that are vital to the process, such as a mouse with liver cells that can express a human function," said Dr. Engelhardt. "We obviously are delighted with the results in this case, and the flexibility it has given us in our continued research and development of therapeutic products."

Enzo Biochem is engaged in the research, development and manufacture of innovative health care products based on molecular biology and genetic engineering techniques, and in providing diagnostic services to the medical community. -0- Except for historical information, the matters discussed in this news release may be considered "forward-looking" statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. Such statements include declarations regarding the intent, belief or current expectations of the Company and its management. Prospective investors are cautioned that any such forward-looking statements are not guarantees of future performance and involve a number of risks and uncertainties that could materially affect actual results.

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