Cell mediated PPD specific cytotoxicity against human monocyte targets: II. IL-2 expansion improves the strength and discriminatory power of CTLs used for cellular typing.

Large batches of Cytotoxic T Lymphocytes (CTLs) specific for antigenic components of Purified Protein Derivative of tuberculin (PPD) were generated from 20 donors. Peripheral Blood Mononuclear cells (PBM) were stimulated with PPD, expanded with Interleukin-2 (IL-2) and finally aliquotted and cryopreserved. It was found that CTLs could be cryopreserved without loss of activity, and compared to generating CTLs in primary culture alone, IL-2 expanded CTLs were stronger and discriminated better. To study their HLA restriction specificity, the CTLs were tested against a panel of 50 target cell donors using PPD pulsed monocytes as antigen presenting target cells. Reproducibility was examined by analysis of variance. Guided by the results, the mean value of 2 tests was selected as the basis for qualitative assignments.