Effects of two bisdioxopiperazines on mouse B-and T-cell function

Area of Science:

• Immunology
• Pharmacology

Background:

• Bisdioxopiperazines (ICRF 154, ICRF 159) and cyclophosphamide (CPA) are known immunosuppressants.
• Their differential effects on B cells and T cells require further elucidation.

Purpose of the Study:

• To assess and compare the immunosuppressive effects of ICRF 154, ICRF 159, and CPA on B cells and T cells.
• To investigate the selective impact of these drugs on different immune cell functions.

Main Methods:

• Mice were treated with ICRF 154, ICRF 159, or CPA.
• Immunization was performed with foreign erythrocytes or allogeneic tumor cells.
• Antibody responses, T cell-dependent cytotoxicity, and plaque-forming cell responses were measured.

Main Results:

• Short-term drug treatment (3-5 days) suppressed antibody responses by inhibiting T-helper cell priming and inactivating B cells.
• T cell-dependent cytotoxicity was partially inhibited or enhanced depending on treatment timing and tumor cell type.
• Prolonged treatment (6 days) with any drug prevented T killer cell generation.
• Pretreatment with drugs before antigen challenge selectively increased T-helper or T-killer cell activity in certain conditions.

Conclusions:

• Bisdioxopiperazines and CPA exhibit selective immunosuppressive effects, primarily on B cells over T cells under specific conditions.
• The timing and duration of drug administration significantly influence the outcome on immune cell function.
• These findings highlight the potential for differential modulation of immune responses by these agents.