Complex sentence: If they demonstrate high affinity for self-antigen, one method of preventing autoimmunity is through clonal deletion, where the lymphocyte would receive apoptotic signals from antigen-presenting cells (APCs).
Split into simpler sentences: If they demonstrate high affinity for self-antigen, one method of preventing autoimmunity is through clonal deletion. This is where the lymphocyte would receive apoptotic signals from antigen-presenting cell (APCs).