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Cytomegalovirus (CMV) is a major infectious cause of death and disease after transplantation. We have previously demonstrated that the tissue-associated adaptive Vδ2neg γδ T cells are key effectors responding to CMV and associated with recovery, contrasting with their innatelike circulating counterparts, the Vγ9posVδ2pos T cells that respond to phosphoantigens but not to CMV. A third Vγ9negVδ2pos subgroup with adaptive functions has been described in adults. In the current study, we demonstrate that these Vγ9negVδ2pos T cells are also components of the CMV immune response while presenting with distinct characteristics from Vδ2neg γδ T cells. In a cohort of kidney transplant recipients, CMV seropositivity was the unique clinical parameter associated with Vγ9negVδ2pos T-cell expansion and differentiation. Extensive phenotyping demonstrated their substantial cytotoxic potential and activation during acute CMV primary infection or reinfection. In vitro, Vγ9negVδ2pos T cells responded specifically to CMV-infected cells in a T-cell receptor-dependent manner and through strong interferon γ production. Finally, Vγ9negVδ2pos T cells were the only γδ T-cell subset in which expansion was tightly correlated with the severity of CMV disease. To conclude, our results identify a new player in the immune response against CMV and open interesting clinical perspectives for using Vγ9negVδ2pos T cells as an immune marker for CMV disease severity in immunocompromised patients., (© The Author(s) 2020. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

The role of human cytomegalovirus (HCMV)-specific T-cell responses in breast milk of HCMV-seropositive mothers is not well defined. In these studies, we demonstrate that the frequency of cytomegalovirus (CMV)-pp65-specific T-cell responses in peripheral blood mononuclear cells (PBMCs) and breast milk cells (BMCs) is increased for CD8+ T cells in both sample sources when compared with CD4+ T cells. The frequency of pp55-specific CD8 T cells producing interferon γ (IFN-γ) alone or dual IFN-γ/granzyme rB producers is increased in breast milk compared with PBMCs. Lastly, we observed a positive correlation between breast milk viral load and the CD8 pp65-specific response, suggesting that local virus replication drives antigen-specific CD8 T cells into the breast., (© The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Brincidofovir is an oral antiviral in development for prevention of cytomegalovirus disease. Cytomegalovirus genotyping results from a phase 2 trial comparing brincidofovir to placebo for prophylaxis against cytomegalovirus infection in hematopoietic cell transplant recipients provided initial data on the clinical resistance profile for brincidofovir. In this study, no known resistance-associated mutations were detected in brincidofovir-treated subjects; identified genotypic substitutions did not confer resistance to cytomegalovirus antivirals in vitro, suggesting that these changes represent polymorphisms unrelated to brincidofovir resistance. Lack of evidence for genotypic resistance during prophylaxis suggests that first-line use of brincidofovir for prevention of cytomegalovirus infection may preserve downstream options for patients., (© The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America.)

Background:  Cytomegalovirus (CMV) infection directly targets vascular endothelium and smooth muscle and at older ages is associated with accelerated vascular pathology and mortality. CMV-specific cellular immunity might directly contribute to this process., Methods:  Conventional ex vivo activation-induced T-cell responses to 19 dominant CMV antigens, along with CMV-specific inducible regulatory-type CD4+ T cells (iTregs), were measured in healthy older people, using a novel protocol that included classic Treg markers alongside the activation marker CD134. Measurements were correlated with diastolic, systolic, and mean arterial blood pressure, a surrogate marker for arterial stiffness., Results:  CMV-specific iTregs recognized the same antigens as conventional CD4+ T cells and were significantly more frequent at older ages. They suppressed antigen-specific and nonspecific proliferation and in large part expressed Foxp3. Frequencies of CMV-specific iTregs and CD8+ T cells (summated response) were significantly associated with diastolic and mean arterial pressures. Confounders, including age, body mass index, smoking, antihypertensive medication use, or C-reactive protein levels, did not explain these observations., Conclusions:  A novel CMV-induced regulatory-type CD4+ T-cell subset is readily detectable in CMV-infected people and, like the aggregate CD8+ T-cell response to the most dominant CMV antigens, is quantitatively associated with arterial stiffness in older life. Whereas CD8+ effector T cells might directly cause vascular injury, iTregs may attenuate this response.

Immunological parameters that distinguish solid-organ transplant (SOT) recipients at risk for life-threatening cytomegalovirus (CMV) disease are being actively pursued to aid posttransplant management. A candidate marker is programmed death (PD)-1 receptor, whose overexpression has been associated with disease progression during persistent viral infections. To determine whether levels of this negative regulator of T cell activity are altered in SOT recipients with symptoms of CMV disease, a comparative PD-1 expression analysis was done in healthy, CMV-positive individuals and in liver transplant recipients. PD-1 levels were measured among the total population of CD8(+) and CD8(+) T cells binding to CMV-specific major histocompatibility complex class I tetramers. Minimal PD-1 expression was found in the healthy, CMV-positive cohort, and symptomatic SOT recipients had significantly higher PD-1 levels. PD-1 up-regulation was significantly associated with incipient and overt CMV disease and with viremia. Our findings suggest that PD-1 could be developed as a prognostic tool to predict CMV disease and guide therapeutic interventions.

We conducted a 12-year retrospective study to determine the effects that the community respiratory-virus species and the localization of respiratory-tract virus infection have on severe airflow decline, a serious and fatal complication occurring after hematopoietic cell transplantation (HCT). Of 132 HCT recipients with respiratory-tract virus infection during the initial 100 days after HCT, 50 (38%) developed airflow decline < or =1 year after HCT. Lower-respiratory-tract infection with parainfluenza (odds ratio [OR], 17.9 [95% confidence interval {CI}, 2.0-160]; P=.01) and respiratory syncytial virus (OR, 3.6 [95% CI, 1.0-13]; P=.05) independently increased the risk of development of airflow decline < or =1 year after HCT. The airflow decline was immediately detectable after infection and was strongest for lower-respiratory-tract infection with parainfluenza virus; it stabilized during the months after the respiratory-tract virus infection, but, at < or =1 year after HCT, the initial lung function was not restored. Thus, community respiratory virus-associated airflow decline seems to be specific to viral species and infection localization.

SERPINB9 is the only known human intracellular inhibitor of granzyme B (GrB), the effector molecule in immunity against cytomegalovirus (CMV) and in renal allograft rejection. Therefore, using specific enzyme-linked immunosorbent assays, we addressed the presence of circulating SERPINB9 during primary CMV infection, subclinical rejection, acute rejection, and uncomplicated posttransplantation course. Soluble (s) SERPINB9 circulates in blood and increases on primary CMV infection. This increase was significantly higher in symptomatic than in asymptomatic patients. In contrast, sSERPINB9 levels did not change in response to subclinical or acute rejection. We demonstrated the presence of circulating sSERPINB9/sGrB complexes, which suggests that SERPINB9 has extracellular functions as well.

Glial cells can respond to herpesvirus infections through the production of cytokines and chemokines. Although specific interactions between resident glia and lymphocytes that infiltrate the infected brain remain to be defined, the presence of T cell chemotactic signals in microglial cell supernatants following infection with cytomegalovirus or herpes simplex virus has led to the concept that chemokines initiate a cascade of neuroimmune responses that result in defense of the brain against herpesviruses. While chemokines may play a defensive role by attracting T cells into the brain, aberrant accumulation of lymphocytes may also induce brain damage. Host defense mechanisms must balance control of herpesvirus spread with associated undesirable immunopathologic effects. A growing body of evidence suggests that through complex networks of chemokines and cytokines produced in response to herpesvirus infection, glial cells orchestrate a cascade of events that result in successful defense of or damage to the brain.

gammadelta T cells undergo massive expansion in the peripheral blood of renal transplant recipients who are infected with cytomegalovirus (CMV). In a 3-year prospective study, the relationship between the evolution of CMV infection and the kinetics of gammadelta T cell amplification was followed for 10 months after transplantation. Patients with late gammadelta T cell expansion (>/=45 days) had significantly longer (P<.0001) and higher (P<.0003) pp65 antigenemia and more-symptomatic CMV disease than did patients with early expansion. Analysis of data for each patient showed that gammadelta T cell expansion is concomitant with the resolution of CMV infection and disease, regardless of the CMV serologic status of donor and recipient before transplantation. These observations point to gammadelta T cell percentage determination as a new, rapid, and reliable prognosis factor to predict the resolution of CMV infection and strongly suggest that gammadelta T cells play a protective role against CMV infection.

We followed 45 seronegative adolescents for acquisition of cytomegalovirus (CMV); 6 (5 female, 1 male) seroconverted after a median of 7.5 months. All were free of signs and symptoms. CMV was isolated from 32 (59.2%) of 54 urines, 2-80 weeks after infection; viruria was less frequent after 6 months. CMV was isolated from saliva of 3 subjects, vaginal swabs of 2 of 5, and 1 white blood cell (WBC) sample. CMV DNA was detected by polymerase chain reaction in WBCs and plasma from all subjects tested. The proportion of WBC samples with CMV DNAemia was 75%-80% within 16 weeks of infection, declining to 0%-25% after 48 weeks. The rate of plasma DNAemia was 25%-40% at 8-16 weeks, declining with time. IgG antibody to CMV, glycoprotein B (gB), and neutralizing antibody were present after 6-8 weeks. Lymphocyte proliferative responses to CMV and to gB were low, compared with those of controls. CMV shedding was of shorter duration than expected. Although antibody response was prompt and vigorous, CMV DNA could be detected in blood for months.

Cytomegalovirus (CMV) DNA levels were measured by quantitative-competitive polymerase chain reaction (PCR) in weekly leukocyte samples from 50 renal transplant recipients, including 23 with symptomatic and 27 with asymptomatic CMV infection. Peak and week 4 CMV DNA levels were higher in symptomatic subjects (P = .07 and .02, respectively). In a logistic regression model, the logarithm of the week 4 level independently predicted symptomatic infection (odds ratio, 1.78 for a 1 log10 increase; 95% confidence interval, 1.14-2.78; P = .01). All subjects whose week 4 level exceeded 1000 copies/100,000 leukocytes developed symptoms. In subjects with adequate samples for analysis, CMV levels declined exponentially with ganciclovir treatment, with an average half-life of 3.3 days. Levels exceeding 10,000 copies were associated with prolonged time to clearing of CMV DNA. Potential clinical applications of quantitative CMV PCR include predicting occurrence of symptomatic first episodes after transplantation and individualizing duration of antiviral therapy.

To study the potential consequences of sperm-mediated sexual cytomegalovirus (CMV) transmission, an in vitro model of microinjection of murine CMV (MCMV) DNA into uninfected fertilized murine ova was used. After microinjected ova were cultured to blastocysts and transferred to pseudopregnant mice, the effect of the DNA on implantation and development was analyzed. At various times, the sites of implantation in the endometrium were examined. Reductions in litter size, fetal growth retardation, resorption of embryos, and fetal maldevelopment, which often involved the central nervous system, were observed. The presence of MCMV DNA sequences in DNA derived from fetuses was detected by the polymerase chain reaction followed by oligonucleotide hybridization. By in situ DNA-DNA cytohybridization and indirect immunofluorescence assays the viral sequences and antigens were localized primarily to the brain, salivary gland, and skin of maldeveloped fetuses. These results establish the potential consequences of sperm-mediated CMV transmission and induction of fetal anomalies.

A mouse model was used for elucidation of the role of a graft-vs-host reaction in promoting cytomegalovirus infection. F1 (DBA/2 X C3H/He) hybrid mice were infected with murine cytomegalovirus. Five weeks later, a graft-vs.-host reaction was produced in the chronically infected animals by the administration of multiple doses of DBA/2 parental splenocytes. Cytomegalovirus was recovered more often from the organs of mice undergoing graft-vs.-host reaction than from those of control animals (P less than 0.001). These results indicate that the graft-vs.-host reaction alone can enhance murine cytomegalovirus infection in a chronically infected host and may help explain the high incidence of cytomegalovirus infection after bone marrow allograft transplantation in man.

We investigated the development of labyrinthitis in animals inoculated with guinea pig cytomegalovirus (GPCMV). These animals all became deaf eight days after inoculation into the perilymphatic compartment and showed severe inflammatory changes within the inner ear. Animals that received inactivated virus maintained their hearing throughout the observation period and exhibited normal cochlear morphology. Neither group had serum or perilymph antibody to GPCMV eight days after viral inoculation. We then investigated the effect of systemic immunity to GPCMV on inner ear viral challenge in animals with high levels of serum antibodies to GPCMV. No significant hearing loss could be detected eight days after inner ear inoculation. Seropositive animals that received live virus demonstrated a significant rise in perilymph antibody titer to GPCMV and showed preservation of normal cochlear morphology. Thus, systemic and inner ear immunity to GPCMV afforded protection against damage caused after direct perilymphatic inoculation of live virus.

A previous report from this laboratory demonstrated that mice infected intraperitoneally with a 0--20% lethal inoculum of murine cytomegalovirus (CMV) exhibited markedly enhanced mortality rates (90%--100%) within 48 hr after an intravenous injection of a 0--20% lethal inoculum of Pseudomonas aeruginosa. The current study demonstrated that mice infected with murine CMV alone had high titers of virus in multiple organs over a 20-day period, whereas mice injected with P. aeruginosa alone had a self-limited infection confined to the kidney. In the combined murine CMV-P. aeruginosa infection, titers of virus in tissues were changed very little. In contrast, P. aeruginosa was recovered in high concentrations from multiple organs, a finding which demonstrated a progressive systemic infection closely resembling that produced by a 100% lethal inoculum of P. aeruginosa alone in normal mice. An increased mortality rate due to P. aeruginosa in murine CMV-infected mice was dependent on inoculation of live bacteria and could not be explained by enhanced susceptibility to endotoxin. These results indicate that murine CMF markedly enhanced the suceptibility of mice to infection with P. aeruginosa and suggest that the virus altered mechanisms of host resistance important in recovery from bacterial infections.