Effect of Cortisone on Genetic Resistance to Mouse Hepatitis Virus in Vivo and in Vitro

Abstract

lOs We are indebted to Dr. Norton Zinder of the Rockefeller Institute for performing the experiments on bacteriophage production. Levallorphan, a nonnarcotic analogue of levorphanol, was used in these experiments because of the legal intricacies involved in the transfer of narcotics from one laboratory to another. We found levallorphan to be a somewhat more potent inhibitor of RNA synthesis than levorphanol.

In vitro macrophage manifestation of cortisone-induced decrease in resistance to mouse hepatitis virus.

“…The slight or equivocal change in macrophage resistance, which had been demonstrated in vitro (7,9), was in no way comparable to the marked effects on the intact animal. Gallily et al (9), using a 1:100 dilution of stock virus (106 LDs0), had found that 85-100% of TAYLOR ET AL. BRIEF DEFINITIVE REPORT cortisone-treated cultures were killed by virus as compared to -20% of cultures given virus alone.…”

“…Cortisone-induced increase in susceptibility of mice to mouse hepatitis virus has also been observed by a number of other investigators as summarized by Vella and Starr (8). Administration of cortisone to the genetically resistant CzI-I mice (9), as well as to outbred mice, rendered them susceptible to viral [MHV(PRI)] infection. The LDs0 of MHV(PRI) virus was 108.5 in PRI mice, 106.5 in cortisone-treated Call mice, and <101'° in untreated Call mice (9).…”

“…Administration of cortisone to the genetically resistant CzI-I mice (9), as well as to outbred mice, rendered them susceptible to viral [MHV(PRI)] infection. The LDs0 of MHV(PRI) virus was 108.5 in PRI mice, 106.5 in cortisone-treated Call mice, and <101'° in untreated Call mice (9). The slight or equivocal change in macrophage resistance, which had been demonstrated in vitro (7,9), was in no way comparable to the marked effects on the intact animal.…”

Contribution of Lewis X Carbohydrate Structure to Neuropathogenic Murine Coronaviral Spread

“…Although TG-elicited PECs (TG-PECs) were introduced as phagocytes with high purity (24), recent studies using flow cytometry revealed that these TG-PECs have heterogeneous population of leukocytes (19). Even macrophages, identified as CD11b hi F4/80 hi-int , after gating out B cells, neutrophils, eosinophils, and DC s from the TG-PECs through flow cytometry, appeared heterogeneous, based on the expression of MHC II and Ly6C antigens (20).…”

Differential growth of MHV(PRI) and MHV(C3H) in genetically resistant C3H mice rendered susceptible by eperythrozoon infection

“…However, under certain conditions these mice have become highly susceptible to the virus (2). The breakdown in genetic resistance necessary for the initiation of virus multiplication is not well understood.…”