Establishment and characterization of continuous helper T cell lines specific to poly(LTyr,LGlu)-poly(DLAla)-poly(LLys)

Murine helper T cells activate to the synthetic polypeptide (T,G)-A-L have been established in vitro as continuous cell lines. In vitro educated cells were obtained by culturing nonadherent spleen cells for 6 days on antigen-pulsed splenic adherent cells. In cases when the initial activation procedure was suboptimal, the helper activity of the cells harvested was further potentiated by reculturing the cells for an additional 24 hr on (T,G)-A-L bearing splenic adherent cells. The educated T cells were further cultivated in medium containing a T cell growth factor (TCGF), without additional antigenic stimulation, and the helper T cell lines obtained have been in culture now for more than 18 mo. The characteristics of 1 of the lines, designated E-9M(+), are described in this paper. The proliferating blast-like cells of this line bear the Thy-1.2 antigen, and they also reacted with antibodies against the variable region of the immunoglobulin heavy chain (VH) as well as with an antiserum against (T,G)-A-L specific idiotypes (Id), as detected by the fluorescence-activated cell sorter (FACS II). The active helper T cells of the E-9M(+) bear Ly-1.1 determinants, and they efficiently activated hapten-primed B cells in an in vitro antibody production system. Culture fluids of this (T,G)-A-L specific helper T cell line could specifically replace the function of T cells in inducing antibody responses. In addition, it was found that the E-9M(+)-derived specific helper factor was absorbed on and eluted from affinity columns of immobilized (T,G)-A-L, anti H-2b, anti-VH, and anti-Id. Thus, this antigen-binding specific helper factor possesses MHC as well as V-region gene determinants.