Mouse Mammary Tumor Virus (MMTV) Morphology in the Gastrointestinal Lumen of Suckling Mice

Abstract

How the milk transmitted MMTV enters the organism is unclear. The site of entrance might be the epithelial cells of the enteric mucosa or the plaques of Peyer. The only ultras true tural study reported to date did not show viruses in the intestinal wall and hypothesized the absorption of a very small quantity of them. The electron microscopy study of the stomach and the small bowel of 8- to 10-day-old BALB/cfRIII suckling mice revealed some morphological changes of the B particles. Some of these changes were obtained in vitro by several means: swelling, breakage, bursting and the consequent release of nucleoids with angular profiles, dense cores, and the tendency to aggregate. Moreover, “head and tail” forms appear frequently as well as smaller B particles, with a diameter of about 800 A. These findings might be the expression of the denaturation of the B particles due to digestion or, at least in part, might represent a step in the absorption process of the MMTV.