Control of immune interferon release by cytotoxic T-cell clones specific for influenza.

We have studied the release of immune interferon (IFN-gamma) by influenza-specific cytotoxic T-cell (Tc) clones. IFN-gamma release is entirely dependent on specific antigen recognition or mitogen treatment and correlates inversely with the growth rate of the clone, while no differences in cytotoxic activity can be discerned at the different stages of Tc maturation. Although the mitogen Con A provides a more powerful stimulus for IFN release by Tc clones, specific antigen leads to a more rapid secretion, starting within 2 hr of contact with Tc clones and their specific targets. This may be of significance in an infection, providing a quick, but localized, mechanism to prevent viral spread. We also examined whether ligand interactions with T-cell surface glycoproteins Lyt-2 or LFA-1, important in Tc recognition, affected IFN release. Monoclonal antibodies to both Lyt-2 and LFA-1 block specific target cell lysis of Tc clone BA4, but do not affect Tc clone T9/5. This latter finding adds LFA-1 to the list of T-cell surface components which are not always essential for target cell recognition. Antibody to Lyt-2 blocked antigen-induced IFN-gamma release by all Tc clones studied, whilst two monoclonal antibodies to LFA-1 had little or no effect. Thus, the Lyt-2 molecule plays a role in the regulation of IFN secretion.