TNFRSF4 and infection: sFc-TNC-CD134L had a modest inhibitory effect on infection with the six viral variants however most sensitive to inhibition were B14 and B28 (Fig. 4C, significant reduction at 10 μg/ml, P = 0.004 and 0.007 respectively), consistent with the enhanced sensitivity of these two strains to anti-CD134 and reduced sensitivity to soluble CD134.