C3-mediated cytoadherence. II. Dependence of cell attachment on similar topographic distribution of the receptors (for C3) and the ligands (C3/C3b).

Particles carrying C3 in a random distribution (Etan-C3) bound to C3 receptor (Raji+) cells independent of temperature and irrespective of whether the Raji cells were fixed with glutardialdehyde. In contrast, the reactivity of EAC43b, having grouped C3b in clusters, was dependent on temperature. The interaction with Raji cells was inhibited if the latter were treated with a fixative.