Transfer factor: a murine model.

Transfer factor has been studied extensively in humans, but a satisfactory subprimate model has not been established. Using BALB/c mice immunized with complete Freund adjuvant, we show that a low-molecular-weight substance derived from disrupted spleen cells transferred sensitivity to purified protein derivative (PPD) to recipient nonimmunized BALB/c mice. Transfer was confirmed by footpad swelling to PPD in vivo and by splenic lymphocyte transformation to PPD in vitro. In recipients of transfer factor, an inverse correlation was noted between the splenic lymphocyte response to PPD and to concanavalin A. Material obtained from spleens of saline-treated BALB/c mice did not transfer sensitivity to PPD to recipient mice.