The present invention provides for an isolated nucleic acid molecule encoding a human TIE-2 ligand. In addition, the invention provides for a receptorbody which specifically binds a human TIE-2 ligand. The invention also provides an antibody which specifically binds a human TIE-2 ligand. The invention further provides for an antagonist of human TIE-2. The invention further provides for a ligandbody which specifically binds TIE-2 receptor. The invention also provides for therapeutic compositions as well as a method of blocking blood vessel growth, a method of promoting neovascularization, a method of promoting the growth, differentiation or migration of cells expressing the TIE-2 receptor, including, but not limited to, hematopoietic precursor cells, a method of blocking the growth, differentiation or migration of cells expressing the TIE-2 receptor including, but not limited to, hematopoietic precursor cells, and a method of attenuating or preventing tumor growth in a human.