Ex vivo analysis of cytotoxic T lymphocytes to measles antigens during infection and after vaccination in Gambian children

The study of cytotoxic T cell responses to measles antigens during infectio n and after vaccination may provide insight into the immunopathology of the infection. It will also provide a knowledge of the immunity conferred by w ild or attenuated virus, which will help in the design of new vaccines. Dir ect cytotoxic T cell responses, which did not require in vitro restimulatio n, were measured from peripheral blood by a standard Cr-51-release assay in 35 patients with acute measles, using HLA class I matched allogeneic B cel ls as targets. 77% showed specific responses to measles fusion protein, 69% to the hemagglutinin, and 50% to the nucleoprotein. These responses, which were related to severity of disease and history of previous vaccination, h ad waned by 14-24 wk after measles when memory responses to the same antige ns could be elicited by restimulation in 71% of the 13 patients tested. A s imilar pattern followed vaccination: direct cytotoxic responses to fusion a nd hemagglutinin proteins were shown in 70% of the 20 children tested while 50% responded to the nucleoprotein. These responses, which were mediated b y both CD8(+) and CD4(+) cells, faded over 6 wk when memory responses could be restimulated. Thus, a vigorous cytotoxic T lymphocyte response to fusio n, hemagglutinin, and nucleoproteins is important in both natural and vacci ne-induced immunity to measles.