borderlands in science : a study in the interactive regeneration of science in the English "popular" Scientific Journal c1865-c1914

The aims of these studies were to characterise the MC IgA receptor, compare it to other established classes of IgA receptor and examine its modulation by cytokines and growth factors.;For these studies primary MC cultures were established from the normal poles of kidney's removed from carcinoma. IgA binding was analysed by flow cytometry, and binding specificity determined by competitive inhibition. The receptor identified was a Fc alpha receptor (FcR) with medium affinity (K 107 M-1) for IgA and was immunogenically distinct from the myeloid Fcr, FcRI. However, the two receptors may share a degree of molecular homology as three mRNA transcripts with partial identity to FcRI were detected in all MC cultures. FcR expression was up-regulated in a time and concentration-dependent manner following exposure to IL-1, IL-6, TNF- and IFN-. Co-exposure with the Th2 cytokine IL-4 antagonised the effects of both IL-1 and TNF-. In all cases a single population of receptors was up-regulated and receptor affinity remained unaltered. Immunoblotting of MC lysates revealed five separate IgA-binding proteins, three of which were also isolated by affinity chromatography from surface radioiodinated MC. The specificity of these proteins for IgA was confirmed in competitive re-binding experiments. Whether these proteins represent subunits or multiple forms of a single receptor, or separate IgA receptors is not yet clear.;Studies are now in progress to sequence the purified receptor proteins. This will ultimately allow full molecular and biochemical characterisation of the MC FcR.