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

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

In a previous study of the effect of cortisone on the resistance of CsH macrophages to MHV(PRI) (6) it had also appeared that cultures maintained in vitro for longer periods of time before testing for viral susceptibility became more susceptible. Since the number of macrophages seen in a culture seemed to in- produce different numbers of macrophages per culture tube, were compared for susceptibility. As may be seen by comparing Text-figs. 2, 3, and 4, increased length of time in culture and increased number of explants in culture reduced the resistance of the macrophages to MHV(PRI). However, all three figures show that with increasing age of mice from which the cells are derived, there is increased resistance. It would appear that the resistance of cells to MHV in tissue culture, which reflects the ontogeny of resistance in mice, may be influenced by the number of cells in culture to some degree. Since these were cultures of liver, it is not known whether the apparent increase in number of macrophages with time or the increase in number of parenchymal liver cells or the total number of cells was responsible for this effect. One experiment with macrophages obtained from peritoneal washing of 12and 16-day-old C~-I mice was performed. Partial destruction was produced with 10 -~ and 10 -~ dilution of virus.