Quantitative measurement of infectious murine cytomegalovirus genomes in real-time PCR

Acute virus replication in murine (M) CMV infected C57BL/6 (Cmv1(r)) mice is severely limited by Ly49H+ NK cells, but not in MCMV infected BALB/c or BXD8 (Cmv1(s)) mice that lack Ly49H+ NK cells. Interestingly, other NK cell receptors may also play a role in MCMV immunity, as CMV encoded gp40 protein can diminish expression of protein ligands recognized by the NK cell receptor NKG2D. To determine whether other additional gene products might influence MCMV immunity, we designed an efficient, sensitive and reliable method for screening resistance or susceptibility phenotypes in mice. Although multiple methods are frequently used to detect and quantify infectious MCMV in mouse tissue samples collected during acute viral infection, these are not readily adaptable to high-throughput screening strategies. Hence, we utilized real-time PCR for detection and quantitative measurement of infectious MCMV genomes present in various tissues of infected mice. MCMV genomic sequence was accurately and reproducibly detected over the range 10(2)-10(8) molecules in mouse genomic DNA samples using this methodology. Importantly, it was found that quantitative real-time PCR and viral plaque assay measurements of MCMV in tissues collected from infected mice, including resistant and susceptible strains, were directly correlated. Moreover, quantitative real-time PCR results obtained during a 3-week time-course study of virus replication in spleens, livers and salivary glands of infected mice demonstrated sensitive, accurate and reproducible detection and measurement of infectious MCMV.     

Mouse cytomegalovirus infection induces antibodies which cross-react with virus and cardiac myosin: a model for the study of molecular mimicry in the pathogenesis of viral myocarditis.

Mouse cytomegalovirus (MCMV) infection induces persisting myocarditis in the susceptible BALB/c strain. Autoantibodies to cardiac myosin are produced in both susceptible BALB/c and resistant C57BL/6 mice following MCMV infection. These affinity-purified anti-cardiac myosin antibodies cross-react with MCMV protein(s). The polypeptides of CMV which share immunological cross-reactivity with the 200,000 MW polypeptide, the heavy chain of myosin, were viral polypeptides of 83,000, 94,000 and 116,000 MW recognized by BALB/c post-infection sera and polypeptides of 66,000 and 94,000 MW recognized by C57BL/6 post-infection sera. Passive transfer of anti-cardiac myosin antibodies from Day 56 post-infection sera of the BALB/c strain induced inflammation and necrosis of the myocardium of uninfected BALB/c recipients. This late immune sera contains autoantibodies specific for the cardiac isoform of myosin. Furthermore, immunization with cardiac myosin induced myocarditis and high titres of cardiac myosin antibodies in uninfected mice of the susceptible BALB/c strain only. However, antibodies to myosin elicited in cardiac myosin-immunized BALB/c mice did not cross-react with MCMV by ELISA. We suggest that virus infection may modulate the immune recognition of the common-epitope(s) shared between MCMV protein(s) and the heavy chain of myosin. Of particular interest is the possibility that molecular mimicry of CMV with cardiac myosin may contribute to the pathogenesis of autoimmune myocarditis following virus infection.     

A flow cytometry-based method for detecting antibody responses to murine cytomegalovirus infection

An assay based on target cells infected with green fluorescent protein labeled murine cytomegalovirus (GFP-MCMV) and dual color flow cytometry for detecting antibody to MCMV is described. After optimizing conditions for this technique, kinetics of anti-MCMV IgG antibody response was tested in susceptible (BALB/c) and resistant (C57BL/6) mouse strains following primary MCMV infection. Previously published antibody kinssetics were confirmed in susceptible mice, with peak IgG response seen approximately 8 weeks after primary infection, decreasing by 20 weeks after infection. In contrast, MCMV resistant C57BL/6 mice showed significantly lower IgG antibody responses than susceptible mice. Although several techniques have been previously described to detect murine antibody responses to MCMV, including nuclear anti-complement immunofluorescence, viral immunoblotting, complement fixation, indirect immunofluorescence, indirect hemagglutination, and enzyme-liked immunosorbent assay techniques, these techniques are all time consuming and laborious. The technique presented is a simple time efficient alternative to detect previous MCMV antibody responses in experimentally infected mice.     

Murine cytomegalovirus

BALB/c and C57BL/6 mice were infected with murine cytomegalovirus (MCMV). On day 4 or 12 of the infection, the animals were immunized with SRBC (T-dependent), TNP-Ficoll (T-independent) and standard poliovirus. The adverse effect of the virus infection on humoral immune responses was limited to animals immunized on day 4; while anti-SRBC antibody formation was severely depressed in both mouse strains, reduced plaque forming cells to TNP-Ficoll were registered only in BALB/c mice. Antibodies to poliovirus were depressed in both strains, although to a lesser degree in C57Bl/6 than in BALB/c mice. Anti-SRBC B cell memory was found to be affected by MCMV infection. These results are interpreted to mean that T-dependent and -independent antigens may be handled differently by the two mouse strains tested.     

Mouse strain differences in the chemokine response to acute lung infection with a murine gammaherpesvirus

Numerous mouse strain-based differences in the immune response and in susceptibility to numerous pathogens have been described, but it is not known if these differences extend to chemokine responses to viral infection of the lungs. To define mouse strain-based differences in the host chemokine response and susceptibility to infection with murine gammaherpesvirus-68 (MHV-68), we compared the induced chemokine response to MHV-68 infection in the lungs of BALB/c and C57BL/6 mice at 1-15 days post-infection. CC and CXC chemokines were induced in both BALB/c and C57BL/6 following infection but the level of chemokine induction was significantly higher in the BALB/c mice for all chemokines measured. In addition, interferon-gamma (IFN-gamma) was also induced to a significantly higher level in the lungs of BALB/c infected mice compared to C57BL/6 mice. Interestingly, viral gene expression was lower in the lungs of C57BL/6 mice during the acute phase of replication. Titers of infectious virus were also greater in BALB/c lungs, although they did not achieve statistical significance. In contrast, latent viral load in the spleen, as measured by quantitative real-time PCR, did not significantly differ between mouse strains, suggesting that the establishment of latency is not affected by the amount of virus present during acute infection. This data suggests that robust chemokine response and expression of IFN-gamma in the lungs of infected BALB/c mice does not correlate with increased resistance to infection. In addition, the significant differences in chemokine responses observed will be important factors to consider in future studies of viral pathogenesis using mouse models.     

Correlation between natural killer cell activation in the bone marrow and haemopoietic dysfunction following cytomegalovirus infection of mice.

We describe here the activation of natural killer (NK) cells in the bone marrows and spleens of mice infected with murine cytomegalovirus (MCMV). NK activity at these sites peaked at day 2 to 3 post-infection (p.i.) and declined between days 6 and 10 p.i. in BALB/c and C57BL/6 mice. In BALB/c mice, the increases in NK activity coincided with depletion of colony-forming units of the granulocyte-monocyte lineage (CFU-GM) from the marrow. CFU-GM depletion in MCMV-infected C57BL/6 mice was less severe, despite the presence of activated NK cells in the marrow. Treatment of BALB/c mice with anti-asialo GM1 prior to MCMV infection resulted in less severe CFU-GM depletion at day 2 p.i. than infection with MCMV alone. When homozygous C57BL/6 or CBA/CaH bg/bg mice were infected with MCMV, depletion of marrow CFU-GM was more severe than in their heterozygous littermates. Finally, we observed some inhibition of colony formation when marrow cells from MCMV-infected and uninfected BALB/c donors were mixed and incubated prior to the CFU-GM assay. These results suggest that activated NK cells may contribute to depletion of haemopoietic cells soon after MCMV infection of BALB/c mice, but may limit the loss of these cells in C57BL/6 and CBA/CaH mice.     

Role of Macrophages in Resistance to Murine Cytomegalovirus

The role of macrophages in protecting mice from murine cytomegalovirus (MCMV) was studied in Swiss, CBA/J, and C57BL/6J mice. CBA/J mice were more resistant to virus than were C57BL/6J mice at all ages tested. Prior treatment of adult Swiss mice with 60 mg of silica, a dose selectively toxic to macrophages, increased mortality due to MCMV infection. Transfer of syngeneic adult macrophages to suckling mice significantly increased their resistance to subsequent MCMV infection. Transfer of syngeneic, nonimmune adult lymphocytes to suckling mice also had a lesser but significant protective effect against subsequent MCMV challenge. In vitro infection of adult CBA/J and C57BL/6J macrophages with virulent and attenuated MCMV resulted in productive infection in only a small percentage of cells and recovery of very little virus from the extracellular fluid. Infection of CBA macrophages was no less productive than C57BL/6J nor was infection with virulent virus more productive than with attenuated virus. Histological examination of the livers of MCMV-infected CBA/J and C57BL/6J mice suggested that divergent cellular immune responses to infection might account for differences in susceptibility. It is postulated that the macrophage may facilitate the inductive phase of cellular immunity, one possible explanation for its demonstrated importance in host defenses against MCMV.     

The association between murine cytomegalovirus induced hepatitis and the accummulation of oval cells

The accumulation of oval cells is an early event in the development of hepatocellular carcinoma induced by certain experimental regimes involving hepatocarcinogens. Oval cells have also been observed during chronic hepatitis induced by alcohol and iron overload. In this study, livers of murine cytomegalovirus (MCMV) infected mice were examined to determine whether hepatitis induced by this virus could initiate oval cell proliferation. BALB/c and C57BL/6 mice were infected with MCMV and studied 4, 8, 10 and 12 months later, alongside control (uninfected) mice. The livers were examined histochemically, immunocytochemically and by in situ hybridization to identify oval cells, inflammatory cells and proliferating cells. Oval cells were seen in the periportal regions of livers from MCMV infected BALB/c mice. These increased in number from 4 to 12 months after infection in parallel with increases in the numbers of inflammatory cells, even though cells expressing MCMV antigens were no longer evident in these samples. Proliferating oval cells and hepatocytes were identified by PCNA staining, indicating an increased level of liver regeneration in the infected livers. C57BL/6 mice are less susceptible to persistent MCMV hepatitis and had fewer oval cells than BALB/c mice. Thus the study demonstrates an association between MCMV induced hepatitis, inflammation, and presence of oval cells.     

Autoantibodies to cardiac myosin in mouse cytomegalovirus myocarditis

Myocarditis accompanies sublethal mouse cytomegalovirus (MCMV) infection in susceptible BALB/c mice and persists beyond the acute phase of infection, in the absence of demonstrable virus antigen but in the continuing presence of autoantibodies to cardiac muscle. Heart tissue autoantibodies of the IgG class were first detected by ELISA in sera at Days 3-5 post-infection (PI) and persisted to Day 100, in two strains of MCMV-infected mice which are susceptible (BALB/c) and resistant (C57BL/10) to MCMV-induced myocarditis. Analysis by immunoblot showed that autoantibodies in early immune sera (Day 10) from both mouse strains reacted with the contractile proteins troponin, tropomyosin and myosin, as well as with other unidentified polypeptides within normal mouse organ homogenates. However, the dominant reactivity of late immune sera (Day 100) was to a 200,000 molecular weight (MW) polypeptide in muscle homogenates identified as the heavy chain of myosin. Autoantibodies reacting with the cardiac or striated muscle isoforms of myosin were assessed by ELISA in BALB/c and C57BL/10 mice. At Days 28, 56 and 100 PI only the susceptible BALB/c strain had high titres of autoantibodies reacting with the cardiac isoform of myosin. Increasing the virus dose given to C57BL/10 mice resulted in slight increases in titres of anti-myosin antibody; however, the peak antibody titres did not approach those of BALB/c mice and persisting myocarditis did not develop. Absorption experiments showed that cardiac myosin-specific antibodies were present in immune sera from susceptible BALB/c mice at Day 100 but not in resistant C57BL/10 mice by ELISA and immunoblot. These results demonstrate that autoimmunity to myosin is a prominent feature of the humoral autoimmune response following MCMV infection, and that there are differences both in fine isoform specificity and titre of anti-myosin antibodies between strains of mice that develop persisting myocarditis and strains that do not. Cardiac myosin-specific autoantibodies may play an immunopathogenic role in CMV-induced myocarditis.     

Differential host determinants contribute to the pathogenesis of 2009 pandemic H1N1 and human H5N1 influenza A viruses in experimental mouse models

Influenza viruses are responsible for high morbidities in humans and may, eventually, cause pandemics. Herein, we compared the pathogenesis and host innate immune responses of a seasonal H1N1, two 2009 pandemic H1N1, and a human H5N1 influenza virus in experimental BALB/c and C57BL/6J mouse models. We found that both 2009 pandemic H1N1 isolates studied (A/Hamburg/05/09 and A/Hamburg/NY1580/09) were low pathogenic in BALB/c mice [log mouse lethal dose 50 (MLD(50)) >6 plaque-forming units (PFU)] but displayed remarkable differences in virulence in C57BL/6J mice. A/Hamburg/NY1580/09 was more virulent (logMLD(50) = 3.5 PFU) than A/Hamburg/05/09 (logMLD(50) = 5.2 PFU) in C57BL/6J mice. In contrast, the H5N1 influenza virus was more virulent in BALB/c mice (logMLD(50) = 0.3 PFU) than in C57BL/6J mice (logMLD(50) = 1.8 PFU). Seasonal H1N1 influenza revealed marginal pathogenicity in BALB/c or C57BL/6J mice (logMLD(50) >6 PFU). Enhanced susceptibility of C57BL/6J mice to pandemic H1N1 correlated with a depressed cytokine response. In contrast, enhanced H5N1 virulence in BALB/c mice correlated with an elevated proinflammatory cytokine response. These findings highlight that host determinants responsible for the pathogenesis of 2009 pandemic H1N1 influenza viruses are different from those contributing to H5N1 pathogenesis. Our results show, for the first time to our knowledge, that the C57BL/6J mouse strain is more appropriate for the evaluation and identification of intrinsic pathogenicity markers of 2009 pandemic H1N1 influenza viruses that are "masked" in BALB/c mice.     

Genetic control of mouse cytomegalovirus-induced myocarditis.

Mouse cytomegalovirus (MCMV) infection of mice induced myocarditis, characterized by a mononuclear cell infiltrate with associated necrosis of myofibres. Myocarditis was observed in parallel with viral inclusion-bearing cells in the heart during the acute phase of the infection. Myocarditis also persisted after the acute phase when viral antigens were no longer detectable by immunoperoxidase histochemistry and infectious virus could not be cultivated from various organs. The influence of host genetic factors on the development of cytomegalovirus-induced myocarditis was investigated using H-2 congenic and recombinant inbred mouse strains. Analysis of congenic variants with C57BL/10 and BALB/c backgrounds and the A/J strain revealed that genes linked to the H-2 complex influenced susceptibility to peak levels of MCMV-induced myocarditis seen 7 and 10 days post-infection. In addition, non-H-2 genes of the BALB/c background were important in determining the severity of myocarditis. Analysis of the strain distribution pattern of the CXB recombinant inbred series did not disclose the identity of the BALB/c non-H-2-linked allele conferring susceptibility to MCMV-induced myocarditis. The level of myocarditis seen in the F1 hybrid between the high-responder BALB/c and low-responder C57BL/6 strains suggested dominant inheritance. The amount of viral replication in the major target organs did not correlate with the severity of myocarditis. In conclusion, at least two genes, one mapping to the H-2 complex and another non-H-2-linked gene, influenced the development of myocarditis in MCMV-infected mice.     

Anti-poliovirus IgG subclass antibodies in cytomegalovirus infected mice

A considerable strain difference was noted in BALB/c and C57BL/6 mice with regard to the impairment of antibody responses to poliovirus antigens in the course of infection with murine cytomegalovirus (MCMV): a long lasting reduction in antibody formation in BALB/c mice contrasted with an only moderate depression observed in C57BL/6 animals. Analysis of antibody classes and IgG subclasses revealed that anti-poliovirus VP1 antibodies in BALB/c mice were predominantly of the IgG3 subclass, a subclass most drastically affected by MCMV infection, while C57BL/6 mice produced antibodies of the IgM class and of IgG1 and IgG2 subclasses which were reduced to a lesser extent by the infection with MCMV. It is concluded that the strain difference observed may be explained on the basis of differences in the handling of poliovirus antigenic determinants by BALB/c and C57BL/6 mice.     

Virus-induced diabetes mellitus. X. Attachment of encephalomyocarditis virus and permissiveness of cultured pancreatic beta cells to infection.

Monolayers of pancreatic β-cells from strains of mice susceptible (SJL/J) and resistant (C57BL/6J) to the development of virus-induced diabetes mellitus were inoculated with the M variant of encephalomyocarditis (EMC) virus. Immunofluorescence showed that viral antigens appeared in up to 10 times more β cells from susceptible SJL/J mice than from resistant C57BL/6J mice. Infectious center assays revealed that 10–30 times more SJL/J β cells contained infectious virus than C57BL/6J β cells. Viral attachment experiments showed no difference in the binding of EMC virus when embryonic fibroblasts, pancreatic fibroblasts, and kidney cells from SJL/J and C57BL/6J mice were compared. However, at least twice as much virus attached to the pancreatic β cells from susceptible than from resistant strains of mice. Our data suggest that genetically determined differences in viral receptors on the surface of β cells may be one of the factors controlling susceptibility to EMC-induced diabetes mellitus.     

Cytomegalovirus infection of adipose tissues induces steatitis in adult mice

Young adult mice infected with MCMV were shown to develop inflammatory lesions in the peripancreatic and salivary gland adipose tissues. MCMV replication was detected by immunoperoxidase staining and electron microscopy in adipocytes, fibroblasts, endothelial cells and pericytes in brown and white adipose tissues. More infected cells were detected in C3H mice than in BALB/c, BALB.B, BALB.K or C57BL/6 mice. Peripancreatic steatitis consisted of a monocytic infiltrate surrounding focal necrosis of adipocytes, the severity of which was influenced by the route of inoculation, virus dose, and genetic susceptibility to disseminated MCMV-disease. C57BL/6 mice showed the greatest susceptibility with severe coalescing focal inflammation around areas of coagulative necrosis. Salivary gland adipose tissues exhibited lymphocytic steatitis, which was reduced in Nu/Nu mice.     

Generation of enhanced macrophage-mediated antibacterial resistance in animals responding to tumor allografts.

Murine cytomegalovirus (MCMV) induces rapid production of a partially pH 2-stable type 1 interferon, the serum level of which is controlled by non-H-2-linked host genes. The production of high, intermediate, and low levels of interferon was found in C3H/He, C57BL/10, and BALB/c mice, respectively, and the use of H-2 congenic mice on the BALB/c or C57BL/10 background showed that H-2-associated genes were not involved. Administration of large (up to 200,000 U) daily doses of partially purified type 1 (alpha plus beta) interferon failed to protect low-producer BALB/c or BALB.K strains from lethal infection. Treatment of the higher (C3H/He) or intermediate (C57BL/10) producer strains with anti-type 1 interferon antibody significantly reduced their resistance to the virus; however, such treatment had no effect on the low-producer BALB/c strain. The decreased resistance of anti-interferon-treated C3H/He mice was accompanied by a transient reduction in serum interferon titers, decreased activation of natural killer cells, a markedly enhanced viremia, and increased viral titers in the liver. These data strongly support a protective role of interferon in defense against MCMV in certain strains of mice. Furthermore, these data suggest that previous observations of a correlation of non-H-2-linked, genetically determined resistance to MCMV with activation of natural killer cells may have its basis in the genetic control of interferon induction by MCMV.     

Genetic control of murine cytomegalovirus infection: Virus titres in resistant and susceptible strains of mice

Summary The course of MCMV infection was studied in a number of inbred strains of mice which differ in their resistance to the development of fatal disease induced by MCMV. Both H-2 and non-H-2 associated genes control this form of resistance and were found to influence the extent of virus replication during sublethal and severe infection. However, for a given strain the summated virus titre of the 5 organs studied was not always proportional to resistance strains. Peak titres of virus were found in the liver and spleen of each strain on days 2 to 3 during high dose infection and in resistant mice during low dose infection. Thereafter titres declined rapidly. When the proportion of the summated virus titre which was present in the spleen and liver was compared for a number of strains, variations in the growth of MCMV in the spleen were noted with 13–84 per cent of virus being found in the spleen of BALB/c, BALB.B, BALB.K and A/WySn mice and usually <3 per cent in the spleen of C57BL/6, C57 BL/10, B10.BR, C3H and CBA mice.With 4 Figures     

Thymus-dependence of autoantibody responses to liver specific lipoprotein in the mouse.

Proposed mechanisms for the induction of autoantibodies to liver specific lipoprotein (LSP) assume that the autoantibody response is T-dependent. This hypothesis was tested in the athymic nude mouse. Athymic homozygote (nu/nu) nude mice and appropriate control mouse strains were immunized with rabbit or human LSP and infected with murine cytomegalovirus (MCMV) in an attempt to induce autoantibodies to LSP. Antibodies to LSP were measured by passive haemagglutination and by an enzyme linked immunosorbent assay. Nude mice did not produce antibodies to either foreign LSP species or autoantibodies to mouse LSP when immunized with either rabbit or human LSP. Control heterozygote (nu/+) mice and C57BL/6J mice produced antibody to foreign LSP and autoantibody to mouse LSP when immunized with xenogeneic LSP. Athymic nu/nu mice also failed to produce autoantibody to mouse LSP following infection with MCMV, in contrast to control nu/+ and C57BL/6J mice which produced LSP autoantibody after infection with MCMV. It is concluded that the autoantibody response to LSP is T-dependent.     

饥饿、糖尿病和肥胖状态对小鼠肝脏SOCS2基因表达的影响

目的确定小鼠肝脏SOCS2基因在饥饿、糖尿病和肥胖状态下的表达水平,并初步研究SOCS2对糖异生的影响。方法动物分3组:C57BL/6J小鼠、对照组(饱食)和实验组(饥饿24 h);糖尿病模型小鼠db/db及对照小鼠db/m饱食;肥胖模型小鼠ob/ob及其对照C57BL/6J小鼠(饱食)。处死小鼠后提取肝脏RNA做反转录PCR,荧光实时定量PCR检测小鼠肝脏SOCS2及糖异生相关基因在3组小鼠中的表达水平;使用腺病毒表达系统在C57BL/6J小鼠原代肝细胞中过表达SOCS2,Western blot检测SOCS2蛋白的表达,葡萄糖生成实验检测糖输出。结果饥饿使C57BL/6J小鼠肝脏中SOCS2 mRNA水平下调,db/db和ob/ob小鼠肝脏SOCS2基因表达比其对照小鼠均明显下降(P0.05),调节糖异生的关键基因PGC-1α、PEPCK和G6Pase的mRNA水平均上升。在C57BL/6J小鼠原代肝细胞中过表达SOCS2,得到大小为Mr 23 000的蛋白,糖输出受到明显抑制。结论初步认定SOCS2可抑制C57BL/6J小鼠原代肝细胞糖异生,可能是治疗糖尿病的一个新靶点。     

Cadaveric skin allograft-associated cytomegalovirus transmission in a mouse model of thermal injury.

As a routine procedure to provide temporary coverage for burn wounds, cadaveric skin allografts have been used in patients with massive thermal injuries. In this study, CMV infection associated with skin grafting was investigated. Graft-associated CMV transmission was shown in a mouse model of thermal injury. Skins from mice 100 days after a nonlethal dose of murine CMV (MCMV) infection contained MCMV DNA and mRNA, although the virus was not isolated from these murine skins. When these skins were grafted to burned mice, the marked growth of MCMV was demonstrated in salivary glands. No viral growth was shown in the salivary glands of unburned mice or CMV sero(+) mice after grafting with these skins. When severe combined immunodeficient beige (SCID-beige) mice were used as recipients for CMV sero(+) skins, all mice died within 30 days after the grafting. Only 1 PFU/mouse of MCMV was shown to be 1 LD(50) in SCID-beige mice, while a 50% mortality rate was shown in normal unburned mice infected with 5 x 10(5) PFU/mouse of MCMV. This indicates that a very small amount of CMV contained in skins is sufficient to induce CMV infection in immunocompromised hosts. On the other hand, human CMV (HCMV) DNA and mRNA were detected by PCR analysis in 55% (DNA) and 33% (mRNA) of cadaveric skins, although the isolation of HCMV from cadaveric skin homogenates was not achieved in tissue cultures. CMV sero(-) patients with severe burn injuries may have a high risk for CMV infection associated with allografts of cadaveric skins.     

Multiple autoantibodies following cytomegalovirus infection: virus distribution and specificity of autoantibodies.

Multiple autoantibodies were found in the sera of BALB/c, C57BL/10 and C3H mice following mouse cytomegalovirus (MCMV) infection. The complex pattern of intra-organ, intratissue and intracellular reactivity observed by immunoperoxidase histochemistry suggested that many autoantibodies of varying specificities were elicited. This evidence from immunoperoxidase histochemistry was confirmed by immunoblot, where autoantibodies binding to polypeptides of a variety of sizes and tissues of origin were observed. In addition to these central findings, the tissue and organ distribution of MCMV in three mouse strains of differing genetic resistance were described. No correlation was found between the distribution of virus and the tissue and organ specificity of the autoantibodies produced following infection. Inflammatory responses accompanied MCMV infection in a number of tissues. In BALB/c mice, myocarditis and salivary gland inflammation were evident at Day 56 post-infection in the absence of MCMV, but in the presence of autoantibodies to cardiac muscle and salivary duct epithelium. This model for virus-induced autoimmunity can be applied to studies of the relationship between virus infection, autoimmunity and disease.