The Rockefeller University

Isolation of human antibodies against Powassan virus for potential therapy vaccine and diagnostic purposes.

Purpose

Powassan virus (POWV) is a virus spread by the same tick that spreads Lyme disease. When humans are bitten by an infected tick they can develop severe disease including encephalitis and POWV infection can be fatal. There is currently no specific treatment available. Ticks carrying the virus are found in several regions of the United States including the upper Midwest and the Northeast. There is concern that cases are increasing and POWV is emerging as a significant public health threat.   Upon infection with germs such as bacteria and viruses the human body mounts a protective response including the production of special proteins called antibodies that block the germs and protect against similar infections in the future. Antibodies are made by special cells in the blood called B cells which have been shown to play important roles in protection from a number of viruses.  B cells can be isolated from blood and analyzed to identify those that make the protective antibody for a specific virus. The genes that code for the protective antibody can be cloned and antibodies can be made outside the body. After they are purified the antibodies are further tested for their ability to bind to and block the virus's ability to infect cells. This has been a successful strategy to obtain HIV blocking antibodies which are being tested in clinical trials and have been found to be safe and to have significant activity against HIV. We propose to take a similar approach to isolate B cells and make antibodies that can block POWV. The antibodies could be useful for POWV treatment or the development of tests  to aid diagnosis and may inform the design of vaccines against this emerging virus.