Study of QUAIL-100 in Pediatric and Young Adult Participants With High-Risk Hematologic Malignancies Who Have Received a Hematopoietic Stem Cell Transplantation

Inclusion Criteria:

* Weight \>/= 10 kg
* Have received HLA-partially matched related or unrelated donor ab-depleted hematopoietic stem cell transplant (HSCT) for high-risk malignant disease and has achieved myeloid and platelet engraftment
* Lanksy/Karnofsky score \> 60
* Participants of childbearing potential must agree to use contraception to prevent pregnancy

Exclusion Criteria:

* Active Grade II acute graft versus host disease (aGVHD) requiring \> 0.5 mg/kg methylprednisolone or any diagnosis of Grade III/IV aGVHD
* Significant cardiac, pulmonary, renal, hepatic, GI, neurological or immunological disease that could compromise safe participation
* Known allergies, hypersensitivity or intolerance to both amoxicillin and gentamycin
* Implanted medical devices with high potential for bacterial seeding, including pacemakers, artificial cardiac valves, prosthetic joints, orthopedic plates or screws, atrial appendage or inferior vena cava devices for thrombosis prevention
* Planned anti-leukemic therapy within 21 days of planned dosing
* Use of tumor necrosis factor (TNF) a or phosphatidylinositol 3-kinase (PI3K) inhibitors within 60 days of screening
* Any prior investigational Listeria product including QUAIL-100
* Live, attenuated vaccine within 4 weeks of first dose