Effects of Trypsin and Certain Surface-Active Agents on Meningo-Pneumonitis Virus and on Normal Chorio-Allantoic Membrane Particulates

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Abstract
Summary and Conclusions: Crude suspensions of meningo-pneumonitis virus from infective allantoic fluid (IAF) and particle suspensions from homogenates of normal chorio-allantoic membranes (NCAM) of chicken embryos were prepared by identical centrifugation and were adjusted to comparable turbidity. The NCAM suspension was considered to be a reasonable control for the IAF suspension because both reacted similarly on incubation with trypsin and morphologically similar particles appeared in both suspensions. Essentially all particles in NCAM and 30 to 50% of particles in IAF suspensions were destroyed by desoxycholate and digitonin under conditions which did not reduce viral infectivity. Two particle classes remained in IAF suspensions after detergent treatment: typical elementary bodies and large forms of 0.5 to 2.0 μ diameter. The large forms were altered tinctorially by detergent exposure which did not alter viral infectivity and some were reduced to empty membranous “ghosts.” Exposure to surface-active agents under conditions which lowered viral infectivity caused nearly the same tinctorial changes in elementary bodies as lesser exposure had produced in large forms, and “ghosts” of elementary bodies appeared. The similarity between elementary bodies and large forms, and the resistance of these structures to treatment which destroyed normal tissue particles, strengthens the morphologic identity of the large forms as viral components of the P-LV group and provides a means of purification of the virus.