Experimental allergic orchitis in mice

Summary Experimental allergic orchids was induced in (C57BL/6J × A/J)F₁ mice by two injections of syngeneic testicular homogenate emulsified with adjuvants immediately followed by intravenous injection of pertussis vaccine, at a 2 week interval.Histologically, in the initial stage there was occasional focal degeneration and desquamation of both spermatogonia and Sertoli cells within limited parts of the seminiferous tubules, in the peripheral region of the testis. No inflammatory change was present. In some cases, however, inflammatory reaction in the rete testis and focal lymphocytic infiltration in the interstitium were also observed. Subsequently, marked infiltration of lymphocytes, monocytes, and polymorphs were found not only in the testes, but also in rete testis and epididymis. In later stages the inflammatory reaction gradually subsided, but the testes became atrophic due to progression of spermatogenic arrest. Many tubules were lined only with monolayers of Sertoli cells, surrounded by hyperplastic Leydig cells in the interstitium. At 5 months after the 2nd immunization, there was still variable depression of spermatogenesis and hyperplasia of Leydig cells with scattered fibrous scars in the seminiferous tubules, although good regeneration of germ cells appeared in some tubules.Immunological studies revealed that lymphocytes obtained from mice bearing developed orchitis showed a significantly enhanced response in the mixed culture with syngeneic testicular cells, and suggest that cellular immunity plays an important role in the induction of experimental allergic orchitis in mice.