B-cells of the synovial membrane. III. Relationship with the specific collagenous structure of the intimal interstitium in the mouse.

An ultrastructural study of the synovial membrane in mice revealed that, in addition to specific polypeptide-producing secretory cells (B-cells), the intima is characterized by a specific differentiation of the interstitium adjacent to the synovial cavity. Scattered collagen fibrils are embedded in a fine fibrillar material, which often appears as cross-striated strands resembling long-spacing-collagen (periodicity from 90 to 120 nm). Similar material was found along the synovial cavity in the rat, guinea pig, rabbit and man. The close relationship between this material and B-cells observed in the mouse suggests that the maintenance of the specialized intimal interstitium may depend on the secretory function of B-cells.