Nath D M, Rodkey L S, Minocha H C
Arch Virol. 1975;48(3):245-52. doi: 10.1007/BF01317967.
Cross hemagglutination inhibition (HI) and neuraminidase inhibition (NI) tests demonstrated strong antigenic relationship between A/Swine/Wisconsin/1/73 (SW/73) and A/Swine/Shope/15/31 (SW/31) influenza viruses. An eigthyone fold purification of virus was achieved by adsorption and elution followed by differential ultracentrifugation and sedimentation through linear sucrose gradient. Radioimmunoassay using purified 125I labeled viral antigens revealed antigenic variation between the two virus isolates. Neuraminidase of both viruses had pH optima between 6.5 and 7.0, and SW/31 enzyme was relatively more heat stable than SW/73.
交叉血凝抑制（HI）试验和神经氨酸酶抑制（NI）试验表明，A/猪/威斯康星/1/73（SW/73）流感病毒与A/猪/肖普/15/31（SW/31）流感病毒之间存在很强的抗原关系。通过吸附、洗脱，然后进行差速超速离心，并通过线性蔗糖梯度沉降，实现了病毒81倍的纯化。使用纯化的125I标记病毒抗原的放射免疫测定揭示了两种病毒分离株之间的抗原变异。两种病毒的神经氨酸酶的最适pH值在6.5至7.0之间，并且SW/31酶比SW/73酶相对更耐热。
