PEGylation of anti-sialoadhesin monoclonal antibodies enhances their inhibitory potencies without impairing endocytosis in mouse peritoneal macrophages.

Poly(ethylene glycol) (PEG) 5 kDa and 20 kDa have been previously conjugated to two anti-sialoadhesin (Sn) monoclonal antibodies (mAbs), SER-4 and 3D6, and shown to dramatically increase their inhibitory potency in solid-phase red blood cell binding assays. In the present study, we evaluated the effect of anti-Sn SER-4 and 3D6 mAbs PEGylation on their inhibition of cell adhesion in mouse peritoneal macrophages. We also examined whether Sn-mediated PEGylation could affect plasma membrane functions of macrophages as to prevent accessibility, binding, and endocytosis of macromolecules and particles.

Differential subcellular membrane recruitment of Src may specify its downstream signalling.

Most Src family members are diacylated and constitutively associate with membrane "lipid rafts" that coordinate signalling. Whether the monoacylated Src, frequently hyperactive in carcinomas, also localizes at "rafts" remains controversial. Using polarized MDCK cells expressing the thermosensitive v-Src/tsLA31 variant, we here addressed how Src tyrosine-kinase activation may impact on its (i) membrane recruitment, in particular to "lipid rafts"; (ii) subcellular localization; and (iii) signalling.