Viral persistence differs in Ly49H⁻ and Ly49H⁺ mice. (A) Titers of replicating virus in salivary glands of infected BALB/c and C57BL/6J mice are shown over a course of infection. Arithmetic means and standard errors are plotted. Data are combined results from at least three independent experiments each using three mice per time point. (B) Viral titers equivalent to those observed in C57BL/6 mice were obtained in Ly49H⁺ BALB/c congenic mice. Arithmetic means and standard errors are plotted. Each data point represents six mice (three BALB.B6-Cmv1r and three BALB.B6-CT8). Data from BALB.B6-Cmv1r and BALB.B6-CT8 were combined because both strains are identical in respect to MCMV growth characteristics in vivo. Day 32 and day 40, P = 0.0022 when comparing Ly49H⁻ with Ly49H⁺ mice. (C) Viral persistence in the salivary glands of Ly49H⁺ mice infected with a mutant virus lacking m157 is reduced, and is equivalent to that observed in Ly49H⁻ mice. Ly49H⁺ C57BL/6 mice were infected with wild-type virus (MCMV-m157^WT) or a virus with a nonfunctional m157 glycoprotein (MCMV-m157^MUT). A revertant virus (MCMV-m157^REV), generated by inserting a functional m157 glycoprotein in the MCMV-m157^MUT, was also used. Organs were collected at days 32, 40, and 50 pi. Titers of replicating virus in the salivary glands are shown as arithmetic means and standard errors. n = 7. Day 40, P = 0.0313 when comparing MCMV-m157^MUT with MCMV-m157^REV.