Influence of naturally occurring human immune complexes on monocyte movement in vitro.

The influence of naturally occurring immune complexes (IC) on monocyte motility has been investigated. Both chemokinesis and chemotaxis have been measured, using modified Boyden chambers, in response to sera containing IC and to the same sera depleted of IC with 2% polyethylene glycol. Chemokinetic activity was markedly increased in the presence of IC-containing sera, and this increased activity was largely abolished, following IC depletion. The chemotactic activity of the IC-containing sera was largely independent of the IC content, since IC depletion only resulted in a modest decrease in stimulated movement. The chemotactic response to a standard chemoattractant (zymosan-treated sera) was significantly increased with the cells in the presence of IC-containing sera, and this effect was abolished following IC depletion. There was no relationship between the total IC concentration and changes in monocyte movement. These results indicate that circulating IC may markedly alter monocyte locomotion in such a way that more cells may be attracted more rapidly to an inflammatory focus.