PERSISTENT HTLV-I INFECTION OF BREAST LUMINAL EPITHELIAL-CELLS - A ROLE IN HTLV TRANSMISSION

Human T cell leukemia viruses are predominantly transmitted from mothe r to child by breast feeding. Endemic levels of HTLV infection are ass ociated with ethnic groups that have traditionally practised long-term breastfeeding. In the course of long-term lactation, we have found th at human milk contains leukocytes and epithelial cells and that mixed primary cultures of these milk cells are susceptible to HTLV-I infecti on in vitro. We have established and characterized an immortalized lin e of milk epithelial cells, HTLV-LEC, that are productively infected a nd transformed with HTLV-I. This is the first reported case of human c ells, other than T cells, that are transformed with HTLV-I. Cultures o f HTLV-LEC are distinctive because of the synthesis of an extensive ex tracellular matrix that appears to support in vitro morphogenesis. HTL V-I infection can be transmitted from HTLV-LEG into normal epithelial cells and leukocytes. Our results suggest that infected epithelial cel ls could be involved in the persistence and transmission of virus infe ction in HTLV-I carriers. (C) 1998 Academic Press.