S. C. Silverstein
= S. C. Silverstein
{c}
<S. C. Silverstein> studied the experimental <cell biology> of <phagocytosis>. Joint work with <S. D. Wright> showed that <complement system> receptor-mediated uptake and release of <hydrogen peroxide> could be separated by comparing ligand-coated culture surfaces.<Receptors for C3b and C3bi promote phagocytosis but not the release of toxic oxygen from human phagocytes by S. D. Wright and S. C. Silverstein>[Abstract; complement and IgG comparisons]{ref}
A 1984 study asked a further physical question: how accessible is the interface between a <macrophage> and its target? The authors compared access of soluble <proteins> beneath <macrophages> spread on glass with access beneath <macrophages> on surfaces coated with ligands promoting <phagocytosis>. The first interface admitted <proteins> with molecular mass as large as $200000$, whereas the ligand-coated interface excluded even tested <proteins> of molecular mass $50000$.<Phagocytosing macrophages exclude proteins from the zones of contact with opsonized targets by S. D. Wright and S. C. Silverstein>[Abstract; differential protein access on glass and ligand-coated glass]{ref}
This supported formation of a seal around the contact region, helping explain why an external scavenging <enzyme> might fail to reach locally released material. It is a compartment-access experiment: exclusion of the tested <proteins> does not establish impermeability to every small <molecule>. The example connects a cellular process with a measurable physical boundary.