Studies have shown that exposure to space conditions actually increases the risk of virus reactivation and infection, endangering the success of a long-duration mission. Dr. Janet S. Butel’s laboratory is studying the immune system responses of both humans and mice in space-like conditions, including the effect of space radiation on immunity and viral infections. Combined with other NSBRI research, this investigation should provide insights into the effects of space flight on infectious diseases and help develop solutions to prevent them.
Overview
Viral Infections and Mucosal Immunity
Principal Investigator:
Janet S. Butel, Ph.D.
Organization:
Baylor College of Medicine
Technical Summary
Space flight has been found to affect immune responses, and alterations in a normal immune response could have a major impact on the hosts ability to control infections. An important question being explored is whether infectious diseases will pose an unacceptable medical risk to the success of long-duration space journeys. All humans are infected for life with latent and persistent viruses, and it is well-known that suppression of the immune system allows latent viruses to reactivate and multiply, which may cause disease in the person undergoing reactivation or in contacts to whom the virus is transmitted.
The general hypothesis being addressed is that conditions of long-duration space flight will alter human immune responses, leading to reactivation of latent viruses, increased viral infections and viral disease, and possible development of malignancies, and to altered mucosal immunity, an important host defense against microbial infections. We are focusing on reactivation and shedding of human herpesvirus EBV and human polyomaviruses, agents known to establish persistent infections and to undergo reactivation and cause disease, including cancer, when the host immune system is compromised. Animal models are being used to study radiation effects on host responses to infections.
The original aims of the project were:
- To determine the effect of space flight conditions on virus reactivation, infection and replication using ground-based models that simulate aspects of space flight;
- To determine the effect of irradiation on the immune system, susceptibility to virus infection, and development of virus-induced cancers in murine animal models; and
- To characterize global changes in mucosal immune responses under simulated space flight conditions in the hind limb unloading (suspended mouse) model.
Key findings of the project this year were from the mouse polyoma virus space radiation model we developed. Preliminary studies suggest that combined effects of radiation and virus infection on the immune system of experimental animals lead to immunosuppression and latent virus reactivations. Because of the observed effects upon immunocompetence and viral replication, it is likely that future studies will be able to offer surrogate marker tests for virus infection and immunocompromise, and new approaches to the prevention and treatment of latent virus reactivation as well as lymphoid malignancies that develop as a consequence.
Earth Applications
Earth Based Applications of Research Project Space flight-induced alterations in the immune system, if serious enough, would have marked adverse effects on host control of microbial infections. Consequences of altered host immunity could result in virus reactivation, replication and disease development, including cancer. As all humans are infected for life with latent or persistent viruses, those infections will be uninvited travelers on all space missions and it is prudent to understand the implications of their presence.
This project's funding ended in 2004