Analysis of the in vitro concanavalin A response of mouse regenerating spleen cells after cyclophosphamide treatment.

Abstract

AbstractThe effect of in vivo cyclophosphamide (Cy) treatment on the in vitro concanavalin A (ConA) response of murine spleen cells was investigated. The ConA dose‐response of the spleen cells in their regenerating phase—7 days after an injection of a sublethal dose (200 mg/kg) of Cy—was significantly different from that of normal spleen cells (N‐SCs); the high‐dose ConA response remarkably increased and the low‐dose ConA response decreased in the spleen cells (Cy‐SCs) taken 7 days after Cy treatment The phenotype of the responder cells in the ConA response of Cy‐SCs was Thy‐1+ and Lyt‐l+2−, the same T subset involved in the ConA response of N‐SCs. Removal of glass wool‐adherent cells from the N‐SCs did not have the same effect as Cy treatment on the ConA dose‐response, and addition of N‐SCs did not suppress an increased response of the Cy‐SCs to high‐doses of ConA.These results indicate that this alteration in the ConA dose‐response induced by in vivo Cy treatment cannot be explained by a decrease in the number of Cy‐sensitive regulatory cells. However, although the ConA response of Cy‐SCs was not affected either by depletion of Sephadex G‐10 adherent cells with a G‐10 column or by depletion of Ia positive cells with anti‐Ia plus complement‐mediated lysis, the ConA response of N‐SCs was inhibited remarkably by both procedures. Furthermore, addition of anti‐Ia antibodies to the cultures decreased the ConA response of N‐SCs, but did not affect the ConA response of Cy‐SCs. Apparently, Lyt‐1+2−T cells in the regenerating phase (on day 7) after Cy treatment required high doses of ConA, but neither the Ia molecule itself nor the Ia+ G‐10 adherent accessory cells (ACs) for maximum stimulation. Therefore, the change in ConA dose‐response induced by Cy treatment on day 7 is thought to be caused by alteration of ConA responsiveness of the regenerating Lyt‐l+2−T cells rather than by a decrease in the Cy sensitive regulatory cells.