The response of the regional lymph node to epididymal sperm granulomas after vasectomy.

The cause of the variable immune response in the regional testicular lymph node of inbred Albino Swiss rats after vasectomy was investigated in two experiments. In the first, the ductus deferens was transected at its junction with the epididymis so that, in every case, sperm granulomas developed in the epididymis, from which lymph is known to drain invariably to the testicular node. In spite of this, not all testicular nodes showed histological signs of an immune response at 12 weeks after vasectomy. In the second experiment the contents of epididymal lymphatics were compared in vasectomised rats and sham-operated controls at intervals of up to 18 months after operation. Lymphatics in animals with an 'active' epididymal granuloma invariably contained numbers of macrophages and lymphocytes, thought to be involved in antigen transport, while those of controls contained none. It is concluded that variations in the lymphatic drainage of vasal granulomas were not primarily responsible for the variable lymph node response to vasectomy previously reported.