Cell-associated immunity to measles (rubeola): The demonstration of in vitro lymphocyte tritiated thymidine incorporation in response to measles complement fixation antigen

Abstract Lack of a reliable in vitro assay for lymphocyte responsiveness to measles (rubeola) has hampered our understanding of the cell-associated response in diseases caused by, or related to, the measles virus. We report a reliable and reproducible system for demonstrating specific lymphocyte incorporation of 3 H-thymidine in response to measles complement fixation antigen (CFA). Seventeen patients with positive histories of measles as children demonstrated a dose-response curve that varied between individuals but was constant for each individual. Kinetic data disclosed maximal responsiveness on day 7, and viral inactivation experiments disclosed that live virus was neither necessary for nor inhibitory to the reaction. The implications of this assay in terms of our understanding of the cell-associated response to measles virus in clinical measles and SSPE are discussed. The concept is explored that membrane-associated antigen is crucial in demonstrating the host's cellular immune response to viruses that can grow by cell-to-contiguous cell spread.