Disclosed herein are antibodies or antigen-binding fragments thereof and compositions comprising the same. Also disclosed are methods of detecting TAR DNA-binding protein 43 (TDP-43) in a biological sample, diagnosing a neurodegenerative disease in a subject, and selecting whether to enroll a subject in a clinical trial for frontotemporal lobar degeneration with TDP-43 inclusions (FTLD-TDP) using the antibodies or antigen-binding fragments thereof described herein. In addition, disclosed herein are immunoassay kits for selectively detecting TDP-43 in a biological sample.