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Earlier studies have shown that epibolin, a glycoprotein in human plasma, identical to preparations from other laboratories referred to as serum spreading factor and vitronectin, requires a second plasma activity in order to support maximal primary epidermal cell spreading. This plasma fraction, referred to as coepibolin, alone supports no cell spreading but potentiates the activity of epibolin by at least 5-10 times. Studies reported here indicate that coepibolin activity associates with one plasma fraction, it cannot be substituted by commercial preparations of ovalbumin, soybean trypsin inhibitor, or hemoglobin, but it can be substituted by commercial bovine or human serum albumin. The activity purified to electrophoretic homogeneity comigrates with, and shows antigenic properties of albumin. Under the assay conditions coepibolin affects the extent and morphology of cell spreading: in the presence of epibolin plus coepibolin cells assume a more polar orientation than in epibolin alone. For its maximal effect coepibolin must be present continuously in the early phases of cell spreading.

The hair follicle undergoes a cycle of growing, regressing, and resting phases (anagen, catagen, telogen, respectively). As the follicle enters catagen, the cells of the lower, cycling portion undergo a process of controlled cell death (apoptosis). Understanding the mechanism of apoptosis in the follicle should give insight into one of the control steps of hair cycling. In this study we sought the expression of bcl-2, a protooncogene associated with apoptosis control, in the cycling follicle of the adult mouse. Using a monoclonal antibody to the mouse protein we immunolocalized bcl-2 gene product in the cycling pelage follicle of the C57/B6 adult mouse. The protein was expressed in the follicular papilla (a non-cycling portion of the follicle) throughout the cycle-including telogen. The cycling follicular epithelium, however, showed positive antibody staining in anagen, which decreased in catagen and disappeared in telogen. In anagen the cells of the bulb, bulge, and basal layer of the outer root sheath expressed the bcl-2 protein. Understanding the action of this apoptosis-inhibiting molecule should serve to elucidate the dynamics of follicular cycling.