Heterogeneity of epidermal Thy-1-positive cells defined by lectin-binding sites

A new cell type that expresses Thy-1 antigen (dendritic epidermal Thy-1-positive cells, d-Thy-1+ EC) was discovered in the murine epidermis in 1983. It is not clear, however, whether all d-Thy-1+EC represent a unitary population. We investigated the cell surface glycoconjugate pattern of d-Thy-1+EC using 6 lectins: concanavalin A (Con-A), Dolichos biflorus agglutinin (DBA), Ricinus communis agglutinin 1 (RCA-1), wheat germ agglutinin (WGA), Ulex europaeus agglutinin (UEA-1), and peanut agglutinin (PNA). These lectins could be divided into 3 groups: lectins binding to most d-Thy-1+EC (Con-A and RCA-1); lectins virtually unreactive with d-Thy-1+EC (DBA and UEA-1); and lectins binding to subpopulation of d-Thy-1+EC (WGA and PNA). For lectins of group 1 and group 2, no difference was observed from strain to strain of mice (C3H/He, BALB/c, and C57B1/6), or from site to site of the body (back, ear, and tail). However, striking difference of percentage of lectin-binding d-Thy-1+EC was observed in group 3 lectins in the tail region compared with the back or the ear, although no strain difference was noted: back or ear, 83.6-95.5% with PNA, 13.6-29.6% with WGA in C3H; tail, 4.0-19.4% with PNA, 30.0-59.1% with WGA in C3H. These results indicate that d-Thy-1+EC are a heterogeneous population and that their distribution is different from site to site in the body.