Interaction of soluble fibroblast surface antigen with fribrinogen and fibrin.

A cell-type specific glycoprotein antigen (SFA) from fibroblast surface appears in human plasma and serum. The amount of SFA in serum was reduced if the blood coagulation clot was removed at a low temperature. SFA could be bound to Sepharose-conjugated fibrinogen and to fibrin powder at 0 degrees C and was subsequently released when the temperature was elevated to plus 37 degrees C.

Polypeptides of a glycoprotein antigen (SF) present in serum and surface of normal but not of transformed chicken fibroblasts.

A protein immunologically identical to a glycoprotein antigen from fibroblast plasma membrane (SF antigen complex) is present in chicken serum. This antigen disappears from cells transformed with tumor viruses. The antigen solubilized from fibroblasts using urea and detergents, and the serum component both gave a molecular weight of about 2-10(5) as estimated by gel filtration on Sepharose 4B.

Localization of the major group-specific protein (p27) of avian tumor viruses by immunofluorescence in chicken cells and tissues.

An immunofluorescence technique was developed for the major group-specific (gs) p27 antigen of avian type C viruses. The localization of this antigen virus-infected in chick embryo fibroblasts was perinuclear, intracytoplasmic and at the cell surface in the majority of the cells, while it was at the cell surface only in some of the cells. No antigen was found in the nucleus.

Distribution of fibroblast surface antigen: association with fibrillar structures of normal cells and loss upon viral transformation.

The localization of a cell type-specific, soluble fibroblast surface antigen (SFA) was studied by immunofluorescence and by scanning electron microscopy of the same cells. The antigen had an uneven distribution forming streaks on chick embryo fibroblasts. It was localized to membrane processes and ridges, with a diameter of 50-200 nm.

Mitogenic effect by lipopolysaccharide and pokeweed lectin on density-inhibited chick embryo fibroblasts.

The B lymphocyte mitogens, bacterial lipopolysaccharide (LPS), pokeweed lectin, and tuberculin, induced proliferation in density-inhibited monolayer cultures of chick embryo fibroblasts. The stimulation was seen both as an early increase in sugar uptake and cell volume and later as an increase in thymidine incorporation and cell number. The concentration of LPS maximally stimulating fibroblasts was remarkably low, about 0.