Effekt der Perjodsäure auf die Erythrocytenmembran

Summary M/2 up to M/500 HJO₄ produces a very peculiar ductility of native erythrocyte membranes, whereas a similar effect is hardly observed on the membranes of trypsin-treated erythrocytes. This observation demonstrates indirectly, probably for the first time, the morphological existence of a loose protein-layer assumed by one of the authors to be present on the surface of erythrocytes.     

Isolierung und Charakterisierung einer Proteinsubstanz der Erythrocytenoberfläche

Summary Through a modified trypsin treatment of the surface of beef-erythrocytes, a substance was isolated with precipitation by a mixture of ethanol and ether, which did not contain significant amounts of hemoglobin and trypsin. A 6N HCl hydrolysate revealed with paper-chromatography 8 amino-acids in this substance. The surface of beef-erythrocyte membranes is covered with a protein- or peptide-layer.     

Cytologische Beobachtungen an Rindererythrocyten mit Hämoglobin-Antikörpern

Summary A commercial crystallised beef-haemoglobin preparation, freed from membranes, produced in rabbits an immune-serum which gave a specific precipitation reaction with haemoglobin and did not agglutinate the trypsin-treated erythrocytes. The haemoglobin is not a structural element of the erythrocyte membrane but it is absorbed to these secondarily during their preparation.     

Syk is indispensable for CpG-induced activation and differentiation of human B cells

B cells are efficiently activated by CpG oligodeoxynucleotides (ODNs) to produce pro-inflammatory cytokines and antibody (Ab). Here, we describe a so far unidentified, spleen tyrosine kinase (Syk)-dependent pathway, which is indispensable for CpG-induced human B cell activation. We show that triggering of B cells by CpG results in Syk and src kinase phosphorylation, proliferation, as well as cytokine and Ab production independent of the BCR. Notably, all these functions are abrogated when Syk is inhibited. We demonstrate that CpG-induced Syk activation originates from the cell surface in a TLR9-dependent manner. While inhibition of Syk does not influence the uptake of CpG ODNs, activation of the kinase is a prerequisite for the delivery of CpG into TLR9-containing endolysosomes and for the CpG-induced up-regulation of TLR9 expression. Our results reveal an alternative, Syk-dependent pathway of CpG-induced B cell stimulation, which is initiated at the plasma membrane and seems to be an upstream requirement for endosomal TLR9-driven B cell proliferation and differentiation.