Disclosed herein are methods for the recombinant expression of mammalian cell membrane-bound human CCN1 or a CCN1 domain thereof in mammalian cells, comprising transforming a mammalian host cell with a vector encoding CCN1 or a CCN1 domain thereof C-terminally fused to a mammalian cell transmembrane domain (CCN1 fusion protein), expressing said CCN1 or CCN1 domain fusion protein in said host cell, and recovering said membrane bound CCN1 or said CCN1 domain thereof. Disclosed herein is the use of such membrane bound CCN1 and domain for the generation of corresponding antibodies. Antibodies against human CCN1 are useful for the treatment of diseases.