Measles virus infection of thymic epithelium in the SCID-hu mouse leads to thymocyte apoptosis (original) (raw)

Measles virus infection induces terminal differentiation of human thymic epithelial cells

Journal of virology, 1999

Measles virus infection induces a profound immunosuppression that may lead to serious secondary infections and mortality. In this report, we show that the human cortical thymic epithelial cell line is highly susceptible to measles virus infection in vitro, resulting in infectious viral particle production and syncytium formation. Measles virus inhibits thymic epithelial cell growth and induces an arrest in the G0/G1 phases of the cell cycle. Moreover, we show that measles virus induces a progressive thymic epithelial cell differentiation process: attached measles virus-infected epithelial cells correspond to an intermediate state of differentiation while floating cells, recovered from cell culture supernatants, are fully differentiated. Measles virus-induced thymic epithelial cell differentiation is characterized by morphological and phenotypic changes. Measles virus-infected attached cells present fusiform and stellate shapes followed by a loss of cell-cell contacts and a shift fro...

Altered virulence of vaccine strains of measles virus after prolonged replication in human tissue

Journal of …, 1999

To understand the molecular determinants of measles virus (MV) virulence, we have used the SCID-hu thymus/liver xenograft model (SCID-hu thy/liv) in which in vivo MV virulence phenotypes are faithfully duplicated. Stromal epithelial and monocytic cells are infected by MV in thymus implants, and virulent strains induce massive thymocyte apoptosis, although thymocytes are not infected. To determine whether passage of an avirulent vaccine strain in human tissue increases virulence, we studied a virus isolated from thymic tissue 90 days after infection with the vaccine strain Moraten (pMor-1) and a virus isolated from an immunodeficient child with progressive vaccine-induced disease (Hu2). These viruses were compared to a minimally passaged wild-type Edmonston strain (Ed-wt) and the vaccine strain Moraten. pMor-1, Hu2, and Ed-wt displayed virulent phenotypes in thymic implants, with high levels of virus being detected by 3 days after infection (10 5.2 , 10 2.8 , and 10 3.4 , respectively) and maximal levels being detected between 7 and 14 days after infection. In contrast, Moraten required over 14 days to grow to detectable levels. pMor-1 produced the highest levels of virus throughout infection, suggesting thymic adaptation of this strain. Similar to other virulent strains, Ed-wt, Hu2, and pMor-1 caused a decrease in the number of viable thymocytes as assessed by trypan blue exclusion and fluorescence-activated cell sorter analysis. Thymic architecture was also disrupted by these strains. Sequence analysis of the hemagglutinin (H) and matrix (M) genes showed no common changes in Hu2 and pMor-1. M sequences were identical in pMor-1 and Mor and varied in H at amino acid 469 (threonine to alanine), a position near the base of propeller 4 in the propeller blade/stem model of H structure. Further study will provide insights into the determinants of virulence.

Increased Thymic Output during Acute Measles Virus Infection

Journal of Virology, 2003

Measles virus infects thymic epithelia, induces a transient lymphopenia, and impairs cell-mediated immunity, but thymic function during measles has not been well characterized. Thirty Zambian children hospitalized with measles were studied at entry, hospital discharge, and at 1-month follow-up and compared to 17 healthy children. During hospitalization, percentages of naïve (CD62L ؉ , CD45RA ؉ ) CD4 ؉ and CD8 ؉ T lymphocytes decreased (P ‫؍‬ 0.01 for both), and activated (HLA-DR ؉ , CD25 ؉ , or CD69 ؉ ) CD4 ؉ and CD8 ؉ T lymphocytes increased (P ‫؍‬ 0.02 and 0.03, respectively). T-cell receptor rearrangement excision circles (TRECs) in measles patients were increased in CD8 ؉ T cells at entry compared to levels at hospital discharge (P ‫؍‬ 0.02) and follow-up (P ‫؍‬ 0.04). In CD4 ؉ T cells, the increase in TRECS occurred later but was more sustained. At discharge, TRECs in CD4 ؉ T cells (P ‫؍‬ 0.05) and circulating levels of interleukin-7 (P ‫؍‬ 0.007) were increased compared to control values and remained elevated for 1 month, similar to observations in two measles virus-infected rhesus monkeys. These findings suggest that a decrease in thymic output is not the cause of the lymphopenia and depressed cellular immunity associated with measles.

Mechanism of Measles Virus–Induced Suppression of Inflammatory Immune Responses

Immunity, 2001

small animal model has impeded progress in understanding the mechanisms of MV-induced immune ab-Bruce Loveland, † Jean-Franç ois Nicolas,* Chantal Rabourdin-Combe,* and Branka Horvat* ‡ § normalities. Monkeys have been used (Auwaerter et al., 1999), but their utilization is extremely restricted by lim-* INSERM U503, CERVI Immunobiologie Fondamentale et Clinique ited supply and high cost. SCID mice grafted with human PBL showed a reduced production of human IgG after Lyon, 69365 France MV infection (Tishon et al., 1996); nevertheless, this model is not convenient for an accurate analysis of anti-† The Austin Research Institute Heidelberg, VIC 3084 gen-specific responses due to the lack of MHC compatibility between murine stromal tissue and human PBL. Australia Cotton rats, susceptible to MV infection, subsequently develop immunosuppression (Niewiesk et al., 1997) but compared to mice are genetically and immunologically Summary poorly characterized. Recently, MV infection of mice expressing CD46, human cellular receptor of MV, was Measles virus (MV) causes profound immunosuppresreported to be associated with immunosuppression sion, resulting in high infant mortality. The mechanisms (Oldstone et al., 1999), though several other reports sugare poorly understood, largely due to the lack of a gested that MV proteins alone can inhibit in vitro immune suitable animal model. Here, we report that particular response (Karp et al., 1996; Schlender et al., 1996; Rava-MV proteins, in the absence of MV replication, could nel et al., 1997). Although these studies confirmed the generate a systemic immunosuppression in mice existence of MV-induced restraint of immune response, through two pathways: (1) via MV-nucleoprotein and the importance of MV replication and the mechanism its receptor Fc␥R on dendritic cells; and (2) via virus responsible for induction of immunosuppression in vivo envelope glycoproteins and the MV-hemagglutinin remains elusive. cellular receptor, CD46. The effects comprise reduced In this report, we investigated the roles of MV proteins hypersensitivity responses associated with impaired in the generation of immunosuppression in vivo. Two function of dendritic cells, decreased production of ILtypes of T cell-dependent inflammatory reactions were 12, and the loss of antigen-specific T cell proliferation. analyzed: delayed type hypersensitivity (DTH) to keyhole These results introduce a novel model for testing the limpet hemocyanin (KLH) mediated by CD4 ϩ T cells immunosuppressive potential of anti-measles vac-(Grabbe and Schwarz, 1998), and contact hypersensitivcines and reveal a specific mechanism of MV-induced ity (CHS) induced by epicutaneous exposure to the hapmodulation of inflammatory reactions. ten dinitrofluorobenzene (DNFB) and mediated by CD8 ϩ T cells (Bour et al., 1995; Kehren et al., 1999). Dendritic Introduction cells play the critical role in the initiation of these inflammatory responses (Grabbe and Schwarz, 1998). We Measles virus (MV) is responsible for an acute childhood demonstrated that MV replication is not necessary for disease that each year infects over 40 million individuals the induction of immunosuppression and that inactiand causes the death of more than 1 million, primarily in vated MV efficiently suppresses hypersensitivity rethe developing world (Murray and Lopez, 1997). The high sponses in mice, after the interaction of viral envelope mortality is associated with transitional MV-induced proteins and nucleoprotein with their respective cellular immunosuppression, enabling secondary infections that receptors. These results suggest that a conventional severely complicate the course of the disease (Beckford murine hypersensitivity model could be directly applicaet al., 1985; Griffin et al., 1994). Measles infection is ble in testing the immunosuppressive effects of antifollowed by the ablation of delayed-type hypersensitivity measles vaccines. Furthermore, they provide evidence responses to tuberculin (Von Pirquet, 1908; Tamashiro et that MV proteins directly induce suppression of inflamal., 1987) and impaired in vitro proliferation of peripheral matory reactions and impair dendritic cell function and blood lymphocytes (PBL) (Hirsch et al., 1984) as well as have important implications in understanding the pathoallospecific cytolytic activity (Galama et al., 1980). Many genesis of MV-induced inhibition of immunity. immunological alterations observed during measles infection also occur at lesser magnitude after vaccination Results of children using attenuated MV (Fireman et al., 1969; Hussey et al., 1996). Inactivated Measles Virus Inhibits Hypersensitivity Responses in Mice ‡ To whom correspondence should be addressed (e-mail: horvat@ We first analyzed whether MV particles could affect the cervi-lyon.inserm.fr).

Induction of CD4 T cell proliferation and in vitro Th1-like cytokine responses to measles virus

Clinical and Experimental Immunology, 2005

Mechanisms that lead to induction of life-long immunity to measles virus (MV) are poorly understood. In the present study, we have assessed the activation, proliferation and cytokine secreting function of peripheral blood T cells from MV immune individuals. Expression of cell blastogenesis markers, such as increased forward light scatter and CD38 expression, peaked 5-7 days after infection of peripheral blood mononuclear cells (PBMC) with the live attenuated Edmonston strain of MV. Subset analysis revealed that both CD3and CD3+ + + + cells expressed activation markers but that the CD3+ + + + T cells predominated late in the culture period corresponding to maximal proliferation and cell recovery. The majority of CD3+ + + + T cells consisted of CD4+ + + + CD8-cells. IFN-g g g g and IL-4 production similarly showed optimal production late in culture. Depletion of CD4 cells prior to culture and MV stimulation completely abrogated both IFN-g g g g and IL-4 production, whereas depletion of CD8 cells did not diminish production, suggesting that CD4+ + + + CD8-T cells were principally involved in production of these cytokines. Finally, optimal IFN-g g g g production was elicited at high MV doses and IL-4 at much lower doses. These results suggest that among MV immune individuals, in vitro responses to measles are dominated by CD4+ + + + T cells that, depending on antigen dose, primarily produce a Th1-like and, to a lesser extent, a Th1/Th2-mixed pattern of cytokine release.

Antigen-Specific Expansion of Cytotoxic T Lymphocytes in Acute Measles Virus Infection

1999

Skewing of the T-cell receptor repertoire of CD81 T cells has been shown in some persistent infections with viruses, such as human immunodeficiency virus, simian immunodeficiency virus, and Epstein-Barr virus. We have demonstrated that similar distortions also occur in nonpersistent measles virus infection. In addition, two of four children immunized with live, attenuated measles virus showed larger and more persistent CD81 T-cell expansions than their naturally infected counterparts. The expanded lymphocyte populations were monoclonal or oligoclonal and lysed target cells infected with recombinant vaccinia virus expressing measles virus protein. These results demonstrate that the expansions of CD81 T lymphocytes are antigen driven. Measles virus (MV) is a negative-strand RNA virus. The clinical symptoms caused by MV infection appear between 2 and 3 weeks after infection. The appearance of the rash is a sign of the peaking immune response and is associated with clearance of the viru...

Measles virus-induced suppression of lymphocyte reactivity in vitro

Cellular Immunology, 1977

Measles virus (Edmonston strain B), in various multiplicities of infection, was added to human lymphocytes which were cultured in medium containing fetal bovine serum. Live measles virus was found to cause an almost complete inhibition of ['HIthymidine incorporation in lymphocytes cultured in the presence of phytohemagglutinin, pokeweed mitogen, tuberculin purified protein derivate (PPD), or allogeneic lymphocytes. Analysis of cell size in the lymphocyte cultures revealed that blast transformation was inhibited as well. Measles virus, inactivated by heat or ultraviolet irradiation, did not cause inhibition. The inhibitory effect of measles virus was only measurable in the initial stages of culture; when added later, i.e., 24 hr before measuring [*HIthymidine incorporation, it had no effect. The diminished reactivity of measles virusinfected lymphocytes cannot be explained by cytopathologic effects or by altered kinetics of lymphocyte transformation. When lymphocytes were cultured at 39°C the extent of virus-induced suppression was significantly reduced. Very small amounts of pooled normal human serum, as well as IgG, prepared from the serum of a patient with subacute sclerosing panencephalitis, were able to prevent the inhibitory effect of measles virus.

Cellular immune responses during complicated and uncomplicated measles virus infections of man

Clinical Immunology and Immunopathology, 1984

Lymphocytes from patients with measles showed profound and prolonged suppression of proliferative responses to mitogens. The degree of suppression was similar in patients with uncomplicated measles virus infection and in those with pneumonia or postinfectious encephalitis. Despite this suppression, lymphocyte responses to measles antigen and PPD were demonstrated in patients with encephalitis and uncomplicated disease, even early in infection. Most patients with pneumonia did not have demonstrable antigen-specific responses. The proportions of T helper (OKT 4) and T suppressor (OKT 8) cells and functional tests of Con A suppressor cell activity showed no significant difference between control and measles patients but, in contrast to controls, cells from measles patients cultured in the absence of any stimulant significantly suppressed the proliferation of allogeneic responder cells. Nine of 20 supematant fluids from these cultures possessed a soluble suppressor factor. These studies indicate varied disruptions of immune reactivity during measles.

Experimental Measles. I. Pathogenesis in the Normal and the Immunized Host

Virology, 1997

An animal model to study measles pathogenesis and the correlates of protective immunity was established using rhesus monkeys. A measles isolate, obtained during an epidemic of measles in the primate colony at the University of California, Davis, was passaged through rhesus monkeys and amplified in rhesus mononuclear cells to create a pathogenic virus stock. Sequence analysis of the nucleoprotein and hemagglutinin genes of this isolate revealed strong homology with the Chicago 89 strain of measles virus. Conjunctival/intranasal inoculation of juvenile rhesus monkeys with this virus resulted in skin rash, pneumonia, and systemic infection with dissemination to other mucosal sites and to the lymphoid tissues. Inflammation and necrosis occurred in the lungs and lymphoid tissues and many cell types were infected with measles virus on Day 7 postinoculation (p.i.). The most commonly infected cell type was the B lymphocyte in lymphoid follicles. Measles antigen was found in follicular dendritic cells on Day 14 p.i. In contrast to naive monkeys infected with measles virus, animals vaccinated with the attenuated Moraten strain did not develop clinical or pathologic signs of measles after challenge. However, moderate to marked hyperplasia occurred in the lymph nodes and spleen of a vaccinated animal on Day 7 after pathogenic virus challenge, suggesting that an effective measles vaccine limits but does not prevent infection with wild-type measles virus.