MNI群ウイルスの同時増殖に関する研究 (第1報)

HVJ (Z) ウイルスとインフルエンザ (A) PR8ウイルスの発育鶏卵漿尿腔内同時増殖実験

抄録

By inoculating the HVJ (Z) virus together with the influenza (A) PR8 virus into the chorioallantoic cavity (CAC) of a developing embryonated egg, they were found to multiply in mixed existence. To obtain the ratio of one strain to the other thus multiplied in mixed existence in the chorioallantoic fluid (CAF), two different methods were employed. One was to utilize the heat fragility of the Z virus and determine the chicken cell agglutinating titers (CCA titers) both before and after the CAF was heated in hot water of 50°C for ten minutes, while the other was to add antiserum to the CAF and thus determine the inhibition titers. When the inhibition titers were determined, however, the inhibitory effect shown by some of them was such as could never be detected in the control experiment in which only the two strains were mixed artificially. Furthermore, the ratios of the two strains in simultaneous growth, when obtained by each of these two different methods, were found to disagree.
The cause for such disagreement and unusual inhibition titers may be considered to be either (1) the changed heat fragility or (2) changed antigenicity of the strains. These variable strains with changed heat fragility or changed antigenicity, however, were found to revert to the pure Z virus or PR8 virus in its original form in the course of serial passages. Consequently, it was impossible to preserve their peculiar characters generation after generation by means of limiting dilution passage.