Augmentation of PPD- and LPS-induced T-independent DNA synthesis in normal mouse spleen cells by leukocyte lysates from tuberculosis patients

We have explored the reported capacity of leukocyte lysates and lysate fractions prepared from tuberculin-positive humans to transfer in vitro responsiveness to purified protein derivative (PPD) to normal mouse spleen cells. Distilled water lysates prepared from such peripheral blood leukocytes (PBL), when added to mouse spleen cells, resulted in a proliferative response to added PPD not engendered by lysates from tuberculin-negative individuals. Dose-response characteristics suggest that transfer is a threshold effect. The most active fraction of such lysates passed through thin dialysis tubing. The phenomenon is complex, in that lysates may be inhibitory in subthreshold concentrations. The mouse cell subpopulation responding to transfer preparations was shown to be T-independent. Interpretation of this phenomenon as representing transfer of specific information is not yet warranted on two grounds: (a) the responding mouse spleen cell subpopulation is apparently stimulated by PPD as a primary mitogen, thus observed responses are properly termed augmentation, and (b) compelling evidence of immunologic specificity of the transferred response is not available.