Heartland Virus Humanized Monoclonal Antibodies for Diagnostic and Therapeutic Development

Heartland virus (HRTV) is a novel tick-borne virus first discovered in 2009 that causes flu-like symptoms such as fever, headaches, fatigue, muscle aches, and diarrhea. Patients with HRTV often have low white blood cell counts, low platelet counts, and abnormal liver function tests which can become severe. Cases of Heartland virus disease have been identified in the Midwestern and southern United States. There are no vaccines to prevent or medications to treat Heartland virus infections. HRTV presents symptoms and generates a similar immune response to other tick-borne viruses, making diagnosis difficult. In order to develop a diagnostic assay that can detect HRTV and distinguish it from other infections, CDC scientists developed and characterized anti-HRTV murine monoclonal antibodies. These monoclonal antibodies (mAbs) react to the viral nucleocapsid (N) protein. The mouse monoclonal antibodies can detect both recent and past infections with specificity to HRTV in diagnostic assays developed by the CDC. These monoclonal antibodies can be engineered to have the murine variable regions reactive with the viral antigen cloned for use as positive controls in assays to detect recent and past infections in humans. These mAbs have been integrated by CDC’s diagnostic lab into a multi-bead array assay, IgM antibody capture ELISA (MAC-ELISA) and IgG ELISA for the detection of recent and past HRTV infections for diagnostic purposes. In addition, research with the humanized antibodies can be done to determine their usefulness as a therapeutic in humans for HRTV infection.