A method is presented for screening cells that produce allogeneic autophagosome enriched compositions able to induce expression of a selective marker on a subpopulation of peripheral blood mononuclear cells, the method comprising contacting a cell with a proteasome inhibitor, contacting the cell with a lysosome inhibitor, harvesting the resulting autophagosomes, determining a molecular signature of the harvested autophagosomes, and selecting cells that divert one or more Toll-like receptor agonist and/or one or more molecular chaperones to the harvested autophagosomes. By screening for cells that divert one or more Toll-like receptor agonist and/or one or more molecular chaperones to the harvested autophagosomes, enriched populations of autophagosomes may be generated which may illicit a specific immune response against numerous cancer types. In this way, an allogeneic, off-the-shelf cancer vaccine may be produced and made available to be administered in order to stimulate a targeted immune response in patients bearing different tumor types.