Human adenoviruses are associated with self-limiting respiratory, conjunctival, and gastrointestinal disease. In immunocompromised people, human adenovirus infection can result in pneumonia, hepatitis, encephalitis, pancreatitis, gastroenteritis, or disseminated disease involving multiple organs (8, 43). Disseminated human adenovirus infection usually results in death. The incidence of disseminated human adenovirus disease is increasing with the increased number of immunocompromised children, and pediatric bone marrow transplant recipients are most at risk (5,12,13,16).Due to species specificity, human adenovirus pathogenesis is poorly understood. Study of mouse adenovirus type 1 (MAV-1) permits the analysis of a replicating adenovirus in vivo. The outcome of infection depends on the virus dose and mouse strain (15,26,33,40). In outbred and C57BL/6 (B6) mouse strains, MAV-1 infects cells of the monocyte-macrophage lineage and endothelial cells (10,20,33). The highest levels of virus are found in the spleen and brain (20,26,39). MAV-1-specific cytotoxic T cells peak at 10 days postinfection (d.p.i.) and then decline (18). T cells cause acute immunopathology and are required for survival 9 to 16 weeks postinfection in MAV-1-induced encephalomyelitis (33). Inbred mouse strains susceptible and resistant to MAV-1 are available, and sublethal irradiation of resistant mice renders them susceptible (40). Mice with a severe combined immunodeficiency (SCID) mutation are susceptible to MAV-1 (10, 35).Here we report findings that survival of acute MAV-1 infection is B-cell dependent and T-cell independent. We postulated that Bruton's tyrosine kinase (Btk) plays a role in protection from MAV-1. Loss of Btk in mice results in the X-linked immunodeficiency (Xid) phenotype (22). Btk Ϫ/Ϫ mice have reductions in serum immunoglobulin (natural antibody), conventional B cells, and peritoneal B-1 cells relative to control mice (22). Here we demonstrate that Btk is required for survival of MAV-1 infection. We present data indicating that early T-cell-independent antiviral immunoglobulin M (IgM) plays a pivotal role in protection against disseminated MAV-1 infection. MATERIALS AND METHODSVirus and mice. Wild-type MAV-1 was propagated and titrated in 3T6 cells (9). The mice used are indicated in Table 1 (11,14,23,24,(29)(30)(31). A ␤ bϪ/Ϫ and Jh mice were purchased from Taconic. C57BL/6NCr (B6) and BALB/CAnNCr mice were purchased from the National Cancer Institute. All other mice were purchased from Jackson Laboratory. The 50% lethal dose (LD 50 ) was determined as described previously (37). Sera were heat inactivated at 57°C for 45 min before passive transfer.Quantitation of virus. Organ homogenates were prepared as described previously (40) or in phosphate-buffered saline (PBS) with 1-mm glass beads (BioSpec Products, Bartlesville, Okla.) in 2 ml/well 96-well plates (Axygen, Union City, Calif.) with a Mini Beadbeater (BioSpec) and the manufacturer's protocol. Virus was titrated by plaque assay as described previously (9). The means of...

Clinical outcomes for MSSA bacteremia did not differ significantly between patients treated with CTX and SOCT. Findings suggest that CTX may be an alternative for outpatient management of MSSA bacteremia.