Lymphopenia produced by polyethylene- 32P strips applied to the rabbit appendix

Abstract

Local, continuous irradiation of the rabbit appendix was produced by attaching to the outer surface of the organ polyethylene strips impregnated with the β-emitting isotope 32P. This procedure reduced the level of small lymphocytes in the blood to 20–25% of the preoperative level after 1 week. The labeling index of small lymphocytes after a single injection of 3H-thymidine showed that there was little or no reduction in the rate of lymphocyte production after attachment of 32P strips. It is argued that the most likely mechanism of the lymphopenia is destruction of a major population of blood lymphocytes which recirculate continuously between the blood and the lymphoid tissue of the appendix. The existence of lymphocyte recirculation within the appendix is regarded as additional evidence that this organ serves a peripheral lymphoid function. Although marked lymphopenia was maintained for 8 weeks or longer, no defect in antibody formation or skin graft rejection was detected. Candida albicans infection of joints progressed and then regressed in similar manner in both groups, leaving a chronic proliferative synovitis lasting for at least 2–3 months.