Mouse mammary tumor virus (MMTV) particles in extraorbital lacrymal and urethral glands of endogenous MMTV-carrying mice.

Expression of mouse mammary tumor virus (MMTV) antigens was observed in a wide variety of exocrine glands in adult mice by an immunoperoxidase method using rabbit antisera against gp52 and p27 of MMTV. Both exogenous and endogenous MMTV-carrying SHN, GRS/A, C3H and DDD-Mtv-2 mice expressed both antigens in the mammary, extraorbital lacrymal, urethral, parotid and submandibular glands of both sexes and prostate, seminal vesicle and epididymis but not in the Harder's, Zymbal's sublingual and uterine glands. Endogenous MMTV-free but exogenous MMTV-carrying BALB/cfC3H mice showed antigen expressions only in the mammary gland. BALB/c mice free from either endogenous or exogenous MMTV did not express viral antigens in any tissues examined. Electronmicroscopically, MMTV A and B particles were detected in the above mentioned MMTV antigen positive non-mammary organs in endogenous MMTV-carrying mice. The results suggested that the endogenously expressing Mtv genes might produce mature MMTV in these non-mammary glandular systems.