Lectins and substitution for helper function in anti-hapten responses in Xenopus laevis

Substitution by lectins for the carrier-priming requirement in thymus-dependent, antigen-binding responses in Xenopus laevis has been examined. Concanavalin A (Con A) was found to substitute for carrier priming in control, early-thymectomized and adult-thymectomized animals, but not in animals given a single, high dose of N-methyl-N-nitrosourea, which has a permanent effect on certain thymus-dependent functions in this species. Lipopolysaccharide and other lectins, such as peanut agglutinin and wheat germ agglutinin, were unable to substitute for carrier priming. These effects of Con A are discussed in terms of substitution via amplifier T cells or a helper T cell subset.