Studies on delayed-type hypersensitivity (DTH) reactions in the pleural cavity in mice: prolonged DTH reaction and its interruption by cyclophosphamide treatment.

DTH reactions to sheep erythrocytes (SRBC) and purified protein derivative (PPD) antigens were produced in the pleural cavity in mice. The profiles of the DTH reactions with respect to time course and cellular exudate reactions differed greatly according to the strains of mice. In particular, HY mice that were established in our laboratory displayed prolonged DTH reactions, characterized by macrophage followed by lymphocyte reactions. HY X C3H F1 mice showed a similar tendency. On the other hand, strains such as C3H, BALB/c, DBA/2 and B6 mice showed short-lived and macrophage-predominant DTH reactions. BALB/c nu/nu mice showed no DTH reactions. Characteristic features of the prolonged DTH reactions in HY mice were transferred with sensitized T cells. However, DTH reactions in HY mice treated with cyclophosphamide (CY) terminated in a short period, and mainly consisted of macrophages and polymorphs, although they were greatly enhanced. Such profiles of the reactions could also be transferred with sensitized T cells from CY-treated and SRBC-sensitized mice. Spleen cells taken from CY-treated and SRBC-sensitized HY mice, when injected intravenously into SRBC-sensitized HY mice just prior to challenge, could not interrupt prolonged DTH reactions. These results thus indicated various phenotypes of the DTH reactions in terms of time course and exudate cellular component involved might be carried by the specific effector T cells in each phenotype of the DTH reactions and could be induced using strains of mice and CY.