In Vitro studies with "Transfer Factor": Transfer of the Cell-Migration Inhibition Correlate of Delayed Hypersensitivity in Humans with Cell Lysates from Humans Sensitized to Histoplasmin, Coccidioidin, or PPD

When “nonsensitive” cells from skin test negative donors were incubated with specific antigen and specific cell lysates obtained from strongly skin test-positive histoplasmin, coccidioidin, or tuberculin skin test donors, the “nonsensitive” cells were “sensitized” and liberated a substance which specifically inhibited the migration of guinea pig macrophages. Cell lysates, antigen, or nonspecific combinations of both, either in the presence or absence of “nonsensitive” cells, failed to inhibit the migration of guinea pig macrophages.