(A) Nested PCR analysis of MCMV ie-1 DNA in lungs and kidneys of Δm157-infected B6;129S-Tnfrsflatm1ImxTnfrsf1btm1Imx mice. Lanes: L, nested PCR analysis of lung DNA from a Smith-infected BALB/c mouse; 1,2,3, nested PCR analysis of DNA isolated from lungs and kidneys of three Δm157 latent B6;129S-Tnfrsflatm1ImxTnfrsf1btm1Imx mice; N, no template control. (B) Titers of reactivated virus in supernatants derived from spleen explants of Smith infected BALB/c mice (WT) or Δm157-infected B6;129S-Tnfrsflatm1ImxTnfrsf1btm1Imx (TNFR-/-) mice. Results shown are the average titers of explants from three mice analyzed in duplicate plus standard deviation.