New Hope for Hepatitis C Patients Found in Chimps
For many, end-stage liver disease is a death sentence for those who are infected with the hepatitis C virus (HCV). Hepatitis C infection is an incurable disease caused by a virus that can eventually lead to severe liver damage and death.
Hepatitis C virus infection is the leading cause of liver transplantations in the U.S. According to the Centers for Disease Control and Prevention, approximately 3.2 million Americans are chronically infected with HCV and approximately 10,000 die annually of the disease.
Recent recommendations made by the CDC concerning hepatitis C infection is that everyone born between 1945 and 1965 should be screened for HCV regardless of whether they have known risk factors such as: a history of drug and substance use, individuals on blood clotting medications, blood transfusions, organ transplantations as well as health care, emergency medical, public safety workers, and children born to HCV-infected mothers.
Because the hepatitis C virus can specifically enter liver cells, it causes inflammation that destroys healthy cells, leaving behind fibrous scar tissue in its wake that then leads to loss of liver function. When the extent of liver damage reaches end-stage liver disease, the only option left is a liver transplantation. However, a transplant is not a cure. As it turns out, in all cases the new liver becomes infected with the hepatitis C virus that remains in the transplant patient’s blood. And then, the cycle of liver disease begins again.
A recent study published in the online journal PLoS Pathogens tells us that there is new hope for hepatitis C transplant patients with the development of a human monoclonal antibody treatment that protects the newly transplanted liver from hepatitis C infection after surgery. Monoclonal antibodies are essentially identical cultured cells (clones) that make only one type of antibody specific for a particular antigen. The antigen in this case is some portion of the hepatitis C virus glycoprotein envelope—a coat that surrounds and protects the virus and aids infection.
Previous research has shown that the glycoprotein envelope is particularly essential for infection of liver cells. When non-hepatitis C viruses were created with the hepatitis C viral coat, the newly created viruses were able to infect liver cells in culture. Therefore, research toward fighting hepatitis C has focused on taking advantage of the infectious abilities of the virus’s envelope coat.
In the study, monoclonal antibodies that specifically target the hepatitis C virus envelope were created and then added to an uninfected liver and incubated for about 30 minutes. The liver was then transplanted into a chimpanzee that was infected with hepatitis C and suffering from liver damage. Chimpanzees were chosen for the study because they are the only animal other than humans that can be infected by the hepatitis C virus.
What the researchers found was that by incubating the transplanted liver with the monoclonal antibodies—hereafter referred to as “HCV1”—just before transplantation, resulted in the HCV1 antibodies binding to and neutralizing the chimp’s hepatitis C virus and thereby protecting the transplanted liver from infection.
According to a press release issued by Texas Biomedical Research Institute:
“This is an important preclinical proof-of-concept study demonstrating a high dose of neutralizing antibody can protect the liver from HCV infection using monoclonal antibodies in a study that was designed to mimic the transplantation setting,” said study co-author Robert E. Lanford, Ph.D., of Texas Biomed.
“One can envision improving on these results with a cocktail of antibodies or by using this antibody with some of the newer antivirals currently in clinical trials. Infection of the new donor liver by residual virus in the patient is one of the major obstacles preventing a full recovery in these patients,” Lanford added.
In addition to these promising results, the researchers have had some success in preventing HCV infection in non-infected chimps given the HCV1 antibodies. However, the results are only preliminary and in need of further investigation.
The researchers report that a phase 1 trial in healthy adults has been completed and HCV1 proved to be safe and well tolerated. Studies are now in progress to examine the efficacy of HCV1 in the prevention of hepatitis C infection of the donor liver in a liver transplant setting.
For an informative article about hepatitis C infection and the new CDC recommendations, follow this link to an article titled “Baby Boomers Urged by CDC to Get Tested for Virus that Kills More U.S. Citizens than HIV.”
Image Source: Courtesy of Wikipedia
Reference: “Human Monoclonal Antibody HCV1 Effectively Prevents and Treats HCV Infection in Chimpanzees” PLoS Pathogens (August 2012 issue); Trevor J. Morin et al.