Use of lectins as mitogens for lymphocytes.

Resting lymphocytes can be induced to undergo DNA synthesis and subsequently cell division and proliferation by a wide variety of agents, but undoubtedly lectins constitute the most convenient generic group of mitogens to pick off the shelf as reagents. Under the influence of strongly mitogenic lectins, a high proportion of T-lymphocytes (irrespective of T-cell receptor specificity) will differentiate into active cytokine-synthesizing cells (helper cells, predominantly with a CD4-positive phenotype) and/or into cells with a functional suppressor or cytotoxic (both predominantly CD8-positive) capacity. Some resting B-lymphocytes will also become activated and subsequently proliferate and differentiate as fully as plasma cells. Although most work has been done in vitro, there is good evidence that some lectins are also mitogenic in vivo (1).