Monoclonal antibody 4C7 recognizes an endothelial basement membrane component that is selectively expressed in capillaries of lymphoid follicles.

In order to define compartment-related structures within the extracellular matrix of human lymphoid organs, monoclonal antibodies (MAbs) were generated by immunizing mice with stromal fragments of human tonsils. One MAb (4C7) was selected which recognized an endothelial basal membrane component that is selectively expressed in capillaries of lymphoid follicles. The epitope was also present in follicles within chronically inflamed synovial membrane and in a hyperplastic thymus of a patient with myasthenia gravis. B-cell non-Hodgkin's lymphomas with a follicular growth pattern expressed the antigen in neoplastic follicles, whereas diffuse growing lymphomas lacked the antigen. The restricted distribution pattern suggests involvement of the 4C7-defined antigen in the organization of the follicular compartment within human lymphoid tissue.