Induction and separation of mouse helper T cells by lectins.

The capability of Lens culinaris agglutinin (LcA) to induce selectively the helper T cell activity affecting primary antibody response was demonstrated. In the presence of mouse spleen cells, activated with LcA at a concentration of 12.5 µg/ml, optimal augumentation of the humoral immune response to sheep erythrocytes (SRBC) was observed. It was also demonstrated that Limulus polyphemus agglutinin (LPA), which was shown to possess carbohydratebinding specificity directed to sialic acid residues, preferentially agglutinated helper T cells. Conversely, peanut agglutinin (PNA), which binds preferentially to the sugar sequence β-D-Gal-(1→3)-D-GalNAc, did not agglutinate the helper cells. Furthermore, the stimulatory effect of LPA-agglutinated cells on the antibody response was abolished by treatment of the cells with anti-Thy-1.2 and complement. These results suggested that the helper cells induced by LcA were T cells and that they have abundant sialic acid residues exposed on the cell surface. [ABSTRACT FROM AUTHOR]