The present invention provides novel proteins and peptides from the receptor binding region of human Growth Arrest Specific Gene 6 (Gas6) and antibodies, including specified portions or variants, specific for at least one such Gas6 peptide or fragment thereof. The aforesaid peptides can be used to generate human, primate, rodent, mammalian, chimeric, humanized and/or CDR-grafted anti-Gas6 antibodies. The invention also provides for the nucleic acids encoding such peptides and anti-Gas6 antibodies, complementary nucleic acids, vectors, host cells, and methods of making and using thereof, including therapeutic formulations, administration and devices. Fifteen novel peptide sequences from the Gas6 G domain that are implicated in Gas6 interactions with its receptors are identified, isolated, and synthesized so as to allow generation of anti-Gas6 antibodies. The peptide sequences include three ESTs that encompass regions predicted to contribute to receptor binding or that can raise anti-Gas6 antibodies. This invention provides for such antibodies to be used in modulating or treating at least one Gas6-related disease in a cell, tissue, organ, animal, or patient. Such diseases may include, but are not limited to, thromboembolic disease, ischemic disease, venous thromboembolism, arterial or venous thrombosis, pulmonary embolism, restenosis, diabetic angiopathy and allograft atherosclerosis.