Cytotoxic T lymphocytes recognize influenza haemagglutinin that lacks a signal sequence
Townsend ARM., Bastin J., Gould K., Brownlee GG.
A surprising feature of most cytotoxic T lymphocytes (CTL) responding to influenza infection is that they recognize the unglycosylated (non-transmembrane) proteins of the virus, including the nucleoprotein 1-4 . Recognition of cells that express nucleoprotein by CTL does not depend on a definite signal sequence within the protein 5 , and the epitopes recognized can be defined with short synthetic peptides in vitro 6 . Haemagglutinin (HA), the major transmembrane protein of the virus, is recognized by a minor population of CTL from infected mice. We have deleted the sequence coding for the N-terminal signal peptide from a complementary DNA encoding HA of the HI subtype. The signal-deleted HA is detected with antibodies as a short-lived, unglycosylated, intracellular protein. However, CTL raised to the complete molecule recognize cells expressing the signal-deleted HA and vice versa. These results cast doubts on the assumption that CTL recognize the HA molecule only after its insertion into the plasma membrane. © 1986 Nature Publishing Group.