Cell surface structures required for B-cell activation with haptenated syngeneic cells.

The requirement for H-2-coded antigens on the cell surface of stimulator cells used for induction of B-cell responsiveness against haptenated (fluorescein isothiocyanate (FITC)) syngeneic cells was studied using H-2-less F9 teratocarcinoma cell lines. I found that FITC-labelled F9 cells, in contrast to normal spleen cells, could not induce hapten-specific antibody synthesis. The effect of treatment of stimulator cells with glutaraldehyde or trypsin before or after hapten labelling was also analysed. It was found that regardless of the order of treatment, hapten-specific antibody synthesis could not be induced by cells treated with glutaraldehyde or trypsin. In addition, hapten-specific B-cell unresponsiveness could not be induced by FITC-labelled glutaraldehyde-treated syngeneic lymphocytes. However, cold targets treated with trypsin or glutaraldehyde efficiently blocked T-cell-mediated cytotoxicity. The requirement for H-2-coded antigens for B-cell activation against haptenated syngeneic lymphocytes is discussed.