Immunoreactive lectins in leaf gel from Aloe barbadensis Miller

Lectins isolated from the gel portion of leaves of Aloe barbadensis Miller by differential centrifugations and gel filtration were found to have strong haemagglutination and mitogenic activities. Haemagglutination titres induced by these lectins were markedly higher than those induced by lectins isolated similarly from Aloe saponaria Haw and Aloe chinesis. The levels of lymphocyte blastogenesis using the Aloe barbadensis Miller lectins were high, but markedly less than those detected using positive control lectins concanavalin A and phytohae‐magglutinin. Results of Western blot transfers followed by immunoblots using specific receptor antisera suggested that the Aloe barbadensis Miller lectins were active at alpha D‐glucose and mannose sites and not at n‐acetyl glucosamine sites. The haemagglutination activities of these Aloe substances were also observed to decrease as a function of time frozen at liquid nitrogen temperatures for up to 9 years.