Acute Hepatitis A Evades Immune System More Effectively Than Chronic Cousin

[Guest guest]

http://www.sciencedaily.com/releases/2011/06/110620161155.htm Acute Hepatitis A

Evades Immune System More Effectively Than Chronic CousinScienceDaily (June 20,

2011) — Ongoing research into the problem of how Hepatitis C becomes a chronic

disease has uncovered a deeper mystery about its sister strain, Hepatitis A.

Hepatitis C is a continuing public health problem, which is difficult to measure

because symptoms occur months to years after infection. The World Health

Organization estimates as many as 2 to 4 million people in the United States may

have chronic Hepatitis C, and most do not know they are infected. More than a

third of those who are long-term carriers may develop chronic liver disease or

liver cancer. " Hepatitis viruses have co-evolved with humans over a very long

period of time and they are good at evading the immune system, but nobody

understands how Hepatitis C becomes a chronic infection, " says Stanley M. Lemon,

MD, professor of microbiology and immunology and a member of UNC Lineberger

Comprehensive Cancer Center and the Center for Translational Immunology. Lemon

and his colleagues thought that Hepatitis C might become chronic by disrupting

the host's interferon response -- part of the innate immune system that protects

the body against any kind of 'foreign' invader. However, their study, published

on-line in the Early Edition of the journal Proceedings of the National Academy

of Sciences U.S.A., came up with some surprising findings.In comparing data from

experiments with Hepatitis A and Hepatitis C, the team found that Hepatitis A

virus, which causes only acute, self-limited disease, is more efficient at

inhibiting the host's interferon response, and that the virus can actually

linger in the body for almost a year. " These results undermine the theory that

evasion of the interferon response is a key mechanism in the development of

chronic Hepatitis C -- the outcome of infection with these viruses is very

different, highlighting how little we understand the unique environment within

the liver for virus-host interactions, " Lemon notes. " It is actually the acute

infection, Hepatitis A, that is stealthier at evading the interferon response. "

In addition to Lemon, the research team included Zongdi Feng, Ph.D., and Daisuke

Yamane, D.V.M, Ph.D. from UNC-Chapel Hill; Lanford, PhD, of the Texas

Biomedical Research Institute and the Southwest National Primate Research

Center; Deborah Chavez, MS, and Bernadette Guerra, BS, from the Texas Biomedical

Research Institute; Kathleen Brasky, DVM, of the Southwest National Primate

Center; Yan Zhou, PhD, and , PhD, of the Center for Vaccines

and Immunity at Nationwide Children's Hospital in Columbus, OH; and Alan

Perelson, PhD, from Los Alamos National Laboratory. The research was funded by

the National Institutes of Health.Story Source:The above story is reprinted

(with editorial adaptations by ScienceDaily staff) from materials provided by

University of North Carolina School of Medicine.Journal Reference: E.

Lanford, Zongdi Feng, Deborah Chavez, Bernadette Guerra, Kathleen M. Brasky, Yan

Zhou, Daisuke Yamane, Alan S. Perelson, M. , and Stanley M.

Lemon. Acute hepatitis A virus infection is associated with a limited type I

interferon response and persistence of intrahepatic viral RNA. PNAS, June 20,

2011 DOI: 10.1073/pnas.1101939108

[Guest guest]

http://www.sciencedaily.com/releases/2011/06/110620161155.htm Acute Hepatitis A

Evades Immune System More Effectively Than Chronic CousinScienceDaily (June 20,

2011) — Ongoing research into the problem of how Hepatitis C becomes a chronic

disease has uncovered a deeper mystery about its sister strain, Hepatitis A.

Hepatitis C is a continuing public health problem, which is difficult to measure

because symptoms occur months to years after infection. The World Health

Organization estimates as many as 2 to 4 million people in the United States may

have chronic Hepatitis C, and most do not know they are infected. More than a

third of those who are long-term carriers may develop chronic liver disease or

liver cancer. " Hepatitis viruses have co-evolved with humans over a very long

period of time and they are good at evading the immune system, but nobody

understands how Hepatitis C becomes a chronic infection, " says Stanley M. Lemon,

MD, professor of microbiology and immunology and a member of UNC Lineberger

Comprehensive Cancer Center and the Center for Translational Immunology. Lemon

and his colleagues thought that Hepatitis C might become chronic by disrupting

the host's interferon response -- part of the innate immune system that protects

the body against any kind of 'foreign' invader. However, their study, published

on-line in the Early Edition of the journal Proceedings of the National Academy

of Sciences U.S.A., came up with some surprising findings.In comparing data from

experiments with Hepatitis A and Hepatitis C, the team found that Hepatitis A

virus, which causes only acute, self-limited disease, is more efficient at

inhibiting the host's interferon response, and that the virus can actually

linger in the body for almost a year. " These results undermine the theory that

evasion of the interferon response is a key mechanism in the development of

chronic Hepatitis C -- the outcome of infection with these viruses is very

different, highlighting how little we understand the unique environment within

the liver for virus-host interactions, " Lemon notes. " It is actually the acute

infection, Hepatitis A, that is stealthier at evading the interferon response. "

In addition to Lemon, the research team included Zongdi Feng, Ph.D., and Daisuke

Yamane, D.V.M, Ph.D. from UNC-Chapel Hill; Lanford, PhD, of the Texas

Biomedical Research Institute and the Southwest National Primate Research

Center; Deborah Chavez, MS, and Bernadette Guerra, BS, from the Texas Biomedical

Research Institute; Kathleen Brasky, DVM, of the Southwest National Primate

Center; Yan Zhou, PhD, and , PhD, of the Center for Vaccines

and Immunity at Nationwide Children's Hospital in Columbus, OH; and Alan

Perelson, PhD, from Los Alamos National Laboratory. The research was funded by

the National Institutes of Health.Story Source:The above story is reprinted

(with editorial adaptations by ScienceDaily staff) from materials provided by

University of North Carolina School of Medicine.Journal Reference: E.

Lanford, Zongdi Feng, Deborah Chavez, Bernadette Guerra, Kathleen M. Brasky, Yan

Zhou, Daisuke Yamane, Alan S. Perelson, M. , and Stanley M.

Lemon. Acute hepatitis A virus infection is associated with a limited type I

interferon response and persistence of intrahepatic viral RNA. PNAS, June 20,

2011 DOI: 10.1073/pnas.1101939108

[Guest guest]

http://www.sciencedaily.com/releases/2011/06/110620161155.htm Acute Hepatitis A

Evades Immune System More Effectively Than Chronic CousinScienceDaily (June 20,

2011) — Ongoing research into the problem of how Hepatitis C becomes a chronic

disease has uncovered a deeper mystery about its sister strain, Hepatitis A.

Hepatitis C is a continuing public health problem, which is difficult to measure

because symptoms occur months to years after infection. The World Health

Organization estimates as many as 2 to 4 million people in the United States may

have chronic Hepatitis C, and most do not know they are infected. More than a

third of those who are long-term carriers may develop chronic liver disease or

liver cancer. " Hepatitis viruses have co-evolved with humans over a very long

period of time and they are good at evading the immune system, but nobody

understands how Hepatitis C becomes a chronic infection, " says Stanley M. Lemon,

MD, professor of microbiology and immunology and a member of UNC Lineberger

Comprehensive Cancer Center and the Center for Translational Immunology. Lemon

and his colleagues thought that Hepatitis C might become chronic by disrupting

the host's interferon response -- part of the innate immune system that protects

the body against any kind of 'foreign' invader. However, their study, published

on-line in the Early Edition of the journal Proceedings of the National Academy

of Sciences U.S.A., came up with some surprising findings.In comparing data from

experiments with Hepatitis A and Hepatitis C, the team found that Hepatitis A

virus, which causes only acute, self-limited disease, is more efficient at

inhibiting the host's interferon response, and that the virus can actually

linger in the body for almost a year. " These results undermine the theory that

evasion of the interferon response is a key mechanism in the development of

chronic Hepatitis C -- the outcome of infection with these viruses is very

different, highlighting how little we understand the unique environment within

the liver for virus-host interactions, " Lemon notes. " It is actually the acute

infection, Hepatitis A, that is stealthier at evading the interferon response. "

In addition to Lemon, the research team included Zongdi Feng, Ph.D., and Daisuke

Yamane, D.V.M, Ph.D. from UNC-Chapel Hill; Lanford, PhD, of the Texas

Biomedical Research Institute and the Southwest National Primate Research

Center; Deborah Chavez, MS, and Bernadette Guerra, BS, from the Texas Biomedical

Research Institute; Kathleen Brasky, DVM, of the Southwest National Primate

Center; Yan Zhou, PhD, and , PhD, of the Center for Vaccines

and Immunity at Nationwide Children's Hospital in Columbus, OH; and Alan

Perelson, PhD, from Los Alamos National Laboratory. The research was funded by

the National Institutes of Health.Story Source:The above story is reprinted

(with editorial adaptations by ScienceDaily staff) from materials provided by

University of North Carolina School of Medicine.Journal Reference: E.

Lanford, Zongdi Feng, Deborah Chavez, Bernadette Guerra, Kathleen M. Brasky, Yan

Zhou, Daisuke Yamane, Alan S. Perelson, M. , and Stanley M.

Lemon. Acute hepatitis A virus infection is associated with a limited type I

interferon response and persistence of intrahepatic viral RNA. PNAS, June 20,

2011 DOI: 10.1073/pnas.1101939108

[Guest guest]

http://www.sciencedaily.com/releases/2011/06/110620161155.htm Acute Hepatitis A

Evades Immune System More Effectively Than Chronic CousinScienceDaily (June 20,

2011) — Ongoing research into the problem of how Hepatitis C becomes a chronic

disease has uncovered a deeper mystery about its sister strain, Hepatitis A.

Hepatitis C is a continuing public health problem, which is difficult to measure

because symptoms occur months to years after infection. The World Health

Organization estimates as many as 2 to 4 million people in the United States may

have chronic Hepatitis C, and most do not know they are infected. More than a

third of those who are long-term carriers may develop chronic liver disease or

liver cancer. " Hepatitis viruses have co-evolved with humans over a very long

period of time and they are good at evading the immune system, but nobody

understands how Hepatitis C becomes a chronic infection, " says Stanley M. Lemon,

MD, professor of microbiology and immunology and a member of UNC Lineberger

Comprehensive Cancer Center and the Center for Translational Immunology. Lemon

and his colleagues thought that Hepatitis C might become chronic by disrupting

the host's interferon response -- part of the innate immune system that protects

the body against any kind of 'foreign' invader. However, their study, published

on-line in the Early Edition of the journal Proceedings of the National Academy

of Sciences U.S.A., came up with some surprising findings.In comparing data from

experiments with Hepatitis A and Hepatitis C, the team found that Hepatitis A

virus, which causes only acute, self-limited disease, is more efficient at

inhibiting the host's interferon response, and that the virus can actually

linger in the body for almost a year. " These results undermine the theory that

evasion of the interferon response is a key mechanism in the development of

chronic Hepatitis C -- the outcome of infection with these viruses is very

different, highlighting how little we understand the unique environment within

the liver for virus-host interactions, " Lemon notes. " It is actually the acute

infection, Hepatitis A, that is stealthier at evading the interferon response. "

In addition to Lemon, the research team included Zongdi Feng, Ph.D., and Daisuke

Yamane, D.V.M, Ph.D. from UNC-Chapel Hill; Lanford, PhD, of the Texas

Biomedical Research Institute and the Southwest National Primate Research

Center; Deborah Chavez, MS, and Bernadette Guerra, BS, from the Texas Biomedical

Research Institute; Kathleen Brasky, DVM, of the Southwest National Primate

Center; Yan Zhou, PhD, and , PhD, of the Center for Vaccines

and Immunity at Nationwide Children's Hospital in Columbus, OH; and Alan

Perelson, PhD, from Los Alamos National Laboratory. The research was funded by

the National Institutes of Health.Story Source:The above story is reprinted

(with editorial adaptations by ScienceDaily staff) from materials provided by

University of North Carolina School of Medicine.Journal Reference: E.

Lanford, Zongdi Feng, Deborah Chavez, Bernadette Guerra, Kathleen M. Brasky, Yan

Zhou, Daisuke Yamane, Alan S. Perelson, M. , and Stanley M.

Lemon. Acute hepatitis A virus infection is associated with a limited type I

interferon response and persistence of intrahepatic viral RNA. PNAS, June 20,

2011 DOI: 10.1073/pnas.1101939108