T cell mitogenicity of a novel β-d-galactoside-specific lectin from the beetle, Allomyrina dichotoma (allo A)

We examined the lymphocyte mitogenicity of a novel β-d-galactoside-specific lectin from the beetle Allomyrina dichotoma, named allo A. Allo A was mitogenic to spleen cells of various strains of mice and rats and to human peripheral blood lymphocytes. When the selectivity of mitogenicity to T or B lymphocytes was examined with mouse spleen cells, allo A was selectively mitogenic to T-enriched spleen cells, which indicates that allo A is a T cell mitogen. Thymocytes from non-treated mice hardly responded to allo A, while those from cortisone-treated mice did to a great extent, indicating that allo A is mitogenic to mature thymocytes. The lymphocyte activation with allo A was inhibited by lactose, but not by melibiose, N-acetyl-d-glucosamine, or methyl-α-d-mannoside, which suggests that cell surface molecules containing β-d-galactosyl residues are of importance in the structure of allo A receptors on the cell surface.