Binding of lectins (Con-A, lens, helix, PHA) to binding sites induced in Tetrahymena by insulin and lectins.

Concanavalin-A (Con-A) gave rise to a moderate aggregation in untreated (control) Tetrahymena pyriformis GL populations. The cells pretreated (imprinted) with insulin or lectins underwent aggregation earlier and to a greater degree than the untreated control cells. Lens lectin, although of the same sugar specificity as Con-A, was considerably less active than the latter. Helix lectin and phytohaemagglutinin (PHA), although of similar sugar specificity, accounted for a dissimilar extent of cell aggregation, in that Helix lectin was comparable in activity to Con-A. Pretreatment (imprinting) with insulin enhanced the aggregation inducing effect of those lectins which were capable of overlapping on the insulin receptor owing to similar specificity.