ONTOGENY OF MACROPHAGE RESISTANCE TO MOUSE HEPATITIS IN VIVO AND IN VITRO

Gallily, Ruth; Warwick, Anne; Bang, Frederik B.

The genetic nature of the susceptibility of mice to one strain of mouse hepatitis has been established previously (2) . Early work suggested that the factor was dominant and unlfactorial (1). Since then a series of 12 backcrosses of susceptible C~I hybrids to resistant C~-I mice have been done, and these continue to show that about 50% of the mice constantly furnish peritoneal washings which are susceptible to the virus (F. B. Bang, I. Velfisto, and A. Warwick, unpublished data). Thus, the unlfactorial nature of this dominant gene seems established. It is important, however, to emphasize that our studies have been limited to one strain of mouse hepatitis which is adapted to, and maintained ha, a susceptible line of mice (PRI). It is likely that different results would be obtained with other strains of virus, for such strains have been recovered from different strains of mice, and at least one of these fails to grow in our susceptible mice (7) . The ability of the virus to change its tissue specificity was apparent in our first study of its growth in macrophage cultures. Only after a series of passages did the virus destroy parenchymal liver cells. Mosely also showed that there was a rapid change of tissue specificity on tissue culture (8) .