[2 types of oncornavirus viroins in epithelial cells from human milk]

Virions of types B and C similar to previously known mammal oncornaviruses were found in tissue cultures prepared from epithelial cells sedimented from the milk of a lactating woman with mammary cancer (HEC-31) and the milk of two clinically normal women (HEC-33 and HEC-34). In HEC-33 culture type C particles were predominant quantitatively. All the three milk specimens gave an identical precipitation line with antiserum for the milk of the mammary cancer patient as well as sequences forming molecular hybrids with DNA product of oncornavirus type D. At the same time, no positive immunologic reaction was obtained with the test system for oncornavirus type D from HEp-2 cells.