COLCHICUM AUTUMNALE AGGLUTININ ACTIVATES ALL MURINE T-LYMPHOCYTES BUTDOES NOT INDUCE THE PROLIFERATION OF ALL ACTIVATED CELLS

Plant lectins with mitogenic properties for T-lymphocytes have been pa rticularly useful for the study of T-cell activation and effector func tions. In the search for mitogenic lectins possessing activation featu res different from the ones associated with the already known mitogens , we found that an agglutinin isolated from Colchicum autumnale tubers , Colchicum autumnale agglutinin (CAA), possesses interesting properti es. First, contrasting with the classical mitogens, CAA induces the pr oliferation of a fraction of the CD4(+) and CD8(+) mouse T-lymphocytes . Second, the CAA-induced proliferation requires MHC class II and CD4 molecules. Third, although only a fraction of T-cells enters into the cell cycle, all T-lymphocytes are activated and express high levels of the activation markers CD69 and CD44. Finally, CAA-stimulation is cha racterized by a particular pattern of the cytokine gene expression, re flected by the transcription of the IL2, IL5, and IFN-gamma genes, whi le the IL4 and IL10 genes remained silent. Taken together these data d emonstrate that CAA activation does not conform to the pathway of T-ce ll triggering observed with classical mitogens and represents a new to ol for the analysis of T-cell activation. (C) 1996 Academic Press, Inc .