THE SPECIFICITY OF T CELLS FOR INFLUENZA VIRUS HEMAGGLUTININ

Abstract

The specificity of T cells recognizing influenza virus hemagglutinin (HA) has been studied using functional assays for helper (TH), suppressor (TS) and delayed-type hypersensitivity (TD) T cells. TH cells raised against one strain of influenza virus cross-react strongly with HA from other viruses of the same subtype, and evidence was also obtained for cross-reactivity between HA subtypes. By using isolated heavy (HA1) and light (HA2) chains and cyanogen bromide-derived fragments of A/Memphis/102/72 HA as antigen in each of the assays, determinants recognized by T cells have been assigned to particular regions of the HA molecule. Determinants for TH cells are carried by the peptides HA1CN1 and HA1CN3, and a determinant is also present on HA2. TS cells are induced by HA1CN1 and HA1CN3, whereas only weak suppression is induced by HA2. Determinants for TD cells are carried by HA1CN1 and HA2CN1. Thus, not only may some determinants for T cells be different from those recognized by B cells, but also the determinants important in stimulation of TH, TS and TD cells may not be identical.