The stem cells that can be propagated and maintained for extended periods of time in culture in the absence of a feeder layer, and can be used to repair tissue damage. These cells are derived from fetal tissues and are able to repair different types of damage in musculoskeletal system, with significantly greater efficacy than stem cells derived from adult tissues. These cells are hypoimmunogenic and can be used for allogeneic transplantation to vertebrate hosts having disease and/or damage in musculoskeletal and other tissues. The cells can be administered by direct injection to the site in need of repair or by systemic (e.g., intravenous) administration. The stem cells of the invention are capable of migrating to the sites in need of repair, and of adopting a phenotype most appropriate to the nature of the damage, injury or disease.
