Lateral diffusion of H-2 antigens on mouse fibroblasts.

Abstract

Fluorescence photobleaching and recovery (FPR) was used to measure the lateral diffusion of mouse H-2 antigens, labeled with fluorescent Fab fragments, in the membrane of [mouse] cl 1d fibroblasts. Diffusion coefficients, D, vary more than 20-fold from cell to cell, though they vary no more than 2-fold when measured at different points on a single cell. The fraction of H-2 antigens mobile, R, also varies from cell to cell, and no lateral diffusion of H-2 antigens can be detected in .apprx. 20% of the cells examined. Treatment of cells with NaCN + NaF, reducing their levels of ATP reduces the proportion of cells in which no lateral diffusion can be detected. The maximum values of D seen in poisoned cells are less than those in controls. Treatment of cells with the divalent inophore, A23187 [calcimycin], greatly increases the proportion of cells in which diffusion of H-2 is rapid, D > 2 .times. 10-9 cm2 s-1.