Alopecia in mice infected with murine cytomegalovirus (MCMV)

When mouse cytomegalovirus was injected subcutaneously into 4-12 day old CDI mice there was infection of dermal cells and the dermal papillae of hair follicles. Infected cells were never seen in the epidermis nor in the epithelium of hair follicles. When larger doses of virus (5 X 10(4) pfu) were given, dermal infection led to gross necrosis of the skin, ulceration, scabbing and healing with alopecia. Smaller doses (10(4) pfu) did not cause gross necrosis but damage to follicles resulted in alopecia or sparse hair growth. Skin lesions were not seen after infection of 4-8 week old mice, even when the inoculated skin area had been epilated, or when hyaluronidase was mixed with the virus inoculum. These experiments show that cytomegalovirus, in contrast to herpes simplex and varicella-zoster viruses, infects dermal but not epidermal cells, and that dermal tropism is age-restricted.