Ultrastructural and cytophotometric studies of lectin binding by human pulmonary macrophages from asthmatic and normal subjects

Abstract

Pulmonary macrophages from normal subjects and asthmatic patients were examined for the presence of sugar residues on their surface. The technique of bronchoalveolar lavage was employed to obtain cell samples. Ultrastructural and cytophotometric methods were used for studying the patterns of lectin binding by these two groups of macrophages. Three lectins, Concanavalin A (Con A), Wheat germ agglutinin (WGA) and Ricinus communis agglutinin (RCA), were used in this investigation. Pulmonary macrophages from both normal and asthmatic persons revealed a high level of Con A, WGA and RCA binding. The distribution of the electron dense reaction product on the macrophage surfaces was relatively uniform. Quantitative cytophotometric studies showed that the level of binding of Con A by macrophages from both groups was approximately the same. Similar results were obtained with WGA--the difference between macrophages from normal and asthmatic persons was not statistically significant. In the case of RCA, macrophages from asthmatic patients showed a higher level of lectin binding than macrophages from normal persons. The conclusion is made that macrophages from asthmatic persons have more D-galactose residues on their surface.