Biomedical subjects

M J Reddehase

Publications and source records attributed to M J Reddehase.

70 records · Page 4Linked to original sources

PubMed1987

Monoclonal antibodies reactive with swine lymphocytes. II. Detection of an antigen on resting T cells down-regulated after activation.

The expression of an antigen on porcine T lymphocytes detected by murine monoclonal antibody (mAb) 8/1 was investigated by functional studies and dual-parameter immunofluorescence. mAb 8/1 reacts with greater than 95% of thymocytes and in peripheral blood with all T lymphocytes and with cells of the monocyte/macrophage lineage, but not with B cells, erythrocytes, and platelets. Pretreatment of peripheral blood lymphocytes with mAb 8/1 plus complement abrogated the proliferative response in vitro to mitogen, soluble antigen, and MHC determinants. Dual-parameter immunofluorescence revealed that resting porcine T8+ as well as T4+ lymphocytes express the 8/1 antigen, whereas after in vitro activation, cell surface expression of the antigen was low or absent in both T cell subsets. Thus, the 8/1 antigen represents a marker that discriminates between resting and activated T lymphocytes. Distribution and functional criteria indicate that 8/1 represents a novel marker not described before for any other mammalian species.

Animals↗

PubMed1987

In vivo application of recombinant interleukin 2 in the immunotherapy of established cytomegalovirus infection.

We have shown in a murine model system for cytomegalovirus (CMV) disease in the immunocompromised host that in vivo application of recombinant human IL-2 (rhIL-2) can enhance the antiviral effect of a limited number of CD8+T lymphocytes, not only in prophylaxis, but also in therapy, when virus has already colonized host tissues. The observed net effect of IL-2 was consistent with the assumption of daily effector population doublings. The prospects for IL-2-supported immunotherapy of established CMV infection depend upon the tissues involved in disease. It appears that the prospects for controlling established CMV adrenalitis are less promising than for a therapy of interstitial CMV pneumonia.

Animals↗

PubMed1987

Simultaneous expression of CD4 and CD8 antigens by a substantial proportion of resting porcine T lymphocytes.

The existence of four subpopulations in resting porcine T lymphocytes is documented. In addition to the two known subpopulations which are typified by a mutually exclusive expression of either the CD8 or the CD4 differentiation antigen, CD4-CD8+ and CD4+CD8- T lymphocytes, respectively, two unusual subpopulations were prominent not only in peripheral blood, but also in lymphoid tissues: CD4-CD8- T lymphocytes expressing neither of these antigens and CD4+CD8+ T lymphocytes coexpressing both antigens. While CD4+CD8+ lymphoblasts have been found also in other species, resting T lymphocytes with that phenotype are without precedent among all species analyzed to date. This unique composition of the porcine T lymphocyte population has to be taken into consideration when the swine is used as a large animal model in experimental medicine.

Animals↗

PubMed1987

Molecular analysis of herpesviral gene products recognized by protective cytolytic T lymphocytes.

The infection of the mouse with murine cytomegalovirus (MCMV) served as a model system to understand the biology of human CMV infection. The contribution of cytolytic T lymphocytes (CTL) to the recovery from infection was studied. Protection against lethal MCMV disease could be conferred on immunodepleted hosts by adoptive transfer of lymphocytes. The antiviral effect was mediated by specifically sensitized T lymphocytes of the CD8+ subset. These cells limited viral spread, prevented tissue destruction by viral cytopathic effects, and protected from lethal disease. Transferred cells have protective therapeutic function even when the virus has already colonized host tissues. CD8+ cells do not require the contribution of CD4+ cells for in vivo function. Selective expression of immediate-early (IE) phase genes in target cells allowed the detection of the immunodominant IE antigen recognized by CTL. The major IE gene ieI encodes a non-structural viral phosphoprotein, pp89, which resides in the nucleus of infected cells where it acts as transcriptional regulator. Expression of gene ieI is under temporal control, and membrane presentation of the protein domain detected by CTL is down-regulated by MCMV early-phase products. A recombinant vaccinia virus expressing gene ieI induced immunity that protected mice against a subsequent challenge with a lethal dose of MCMV. The protective effect was entirely mediated by CD8+ T lymphocytes. Thus, an experimental vaccine expressing a single nonstructural herpesvirus protein can induce a protective cellular immune response.

Animals↗

PubMed1987

Stable expression of clonal specificity in murine cytomegalovirus-specific large granular lymphoblast lines propagated long-term in recombinant interleukin 2.

The somatic stability of cloned long-term cytolytic T lymphocyte lines (CTLL) specific for antigens encoded by murine cytomegalovirus (MCMV) was tracked for more than two years of continuous in vitro propagation. Clone S1 retained its original specificity for a structural (S) antigen of MCMV for about eight months in the presence of antigen and interleukin 2 (IL 2), but not in IL 2 alone. In the following months, however, in spite of the continued presence of antigen, clonal variants developed that displayed distinct patterns of target cell recognition, including loss of the original specificity and acquisition of exclusive specificity for the natural killer target cell YAC-1. On the other hand, large granular lymphoblast (LGL) lines, line IE1-IL and a series of sublines thereof, could be established that stably expressed Ld-restricted specificity for a viral nonstructural immediate-early (IE) antigen more than two years after withdrawal of antigen and feeder cells when propagated in the presence of pure recombinant human IL 2. The finding that the presence of antigen was not essential for the stability of clone IE1-derived CTLL indicates that maintenance of specificity in LGL lines is not a result of antigen-mediated selection, but reflects an intrinsic property.

Animals↗

PubMed1987

CD8-positive T lymphocytes specific for murine cytomegalovirus immediate-early antigens mediate protective immunity.

We have shown in a murine model system for acute, lethal cytomegalovirus (CMV) disease in the immunocompromised natural host that control of virus multiplication in tissues, protection from virus-caused tissue destruction, and survival are mediated by virus-specific CD8+ CD4-T lymphocytes. Protection from a lethal course of disease did not result in a rapid establishment of virus latency, but led to a long-lasting, persistent state of infection. The CD8- CD4+ subset of T lymphocytes was not effective by itself in controlling murine CMV (MCMV) multiplication in tissue or essential for the protective function of the CD8+ CD4- effector cells. The antiviral efficacy of the purified CD8+ CD4- subset was not impaired by preincubation with fibroblasts that presented viral structural antigens, but was significantly reduced after depletion of effector cells specific for the nonstructural immediate-early antigens of MCMV, which are specified by the first among a multitude of viral genes expressed during MCMV replication in permissive cells. Thus, MCMV disease provides the first example of a role for nonstructural herpesvirus immediate-early antigens in protective immunity.

Animals↗

PubMed1987

Host immune response to cytomegalovirus: products of transfected viral immediate-early genes are recognized by cloned cytolytic T lymphocytes.

To confirm that immediate-early (IE) genes of murine cytomegalovirus (MCMV) give rise to antigens recognized by specific cytolytic T lymphocytes (CTL), a 10.8-kilobase fragment of MCMV DNA which is abundantly transcribed at IE times was transfected into L cells expressing the Ld class I major histocompatibility glycoprotein. The viral genome fragment contains sequences of the three IE transcription units of MCMV: ie1, ie2, and ie3. In the transfected cell lines, only the predominant 2.75-kilobase transcript of ie1 and its translation product pp89 could be detected. The transfectants were analyzed for membrane expression of an IE antigen by employing clone IE1, an IE-specific CTL clone, as the probe. Only cells that expressed both the MCMV IE gene(s) and the Ld gene were recognized by the CTL clone.

Antigens, Viral↗

PubMed1986

Cloned long-term cytolytic T-lymphocyte line with specificity for an immediate-early membrane antigen of murine cytomegalovirus.

Long-term cytolytic T-lymphocyte (CTL) lines that are specific for distinct antigens associated with different phases of the replicative cycle of the murine cytomegalovirus (MCMV) were established by cloning of CTL lines derived from lymph nodes of latently infected BALB/c mice. Two CTL clones were characterized in detail. Both displayed the Lyt-2+, L3T4- surface phenotype, and the recognition of their respective target antigens was class I (DLd) major histocompatibility complex antigen restricted. Clone S1 was specific for a structural antigen of MCMV, and clone IE1 detected an MCMV-specified immediate-early (IE) membrane antigen. Clone IE1 retained lytic activity, antigen specificity, and self-restriction after prolonged propagation in the presence of recombinant human interleukin-2 without restimulation by antigen. This interleukin-2-dependent line of the clone IE1, line IE1-IL, can serve as a reference line for the definition of the antigenic determinant IE1 of an IE membrane antigen.

Animals↗

PubMed1986

Late-phase expression of a murine cytomegalovirus immediate-early antigen recognized by cytolytic T lymphocytes.

The cloned murine cytolytic T-lymphocyte line IE1-IL and several sublines detect a murine cytomegalovirus immediate-early (IE) membrane determinant in conjunction with Ld class I major histocompatibility glycoprotein. The lines retained cytolytic activity, strict antigen specificity, and self-restriction even when adapted to long-term, antigen-independent growth in the presence of interleukin-2 only (M. J. Reddehase, H.-J. Bühring, and U. H. Koszinowski, J. Virol. 57:408-412). These attributes allowed us to use IE1-IL as a stable, monospecific probe for tracing the expression of the IE membrane antigen throughout the viral replication cycle. Presentation of the antigen at the cell membrane proved to be most effective when expression of IE genes in infected mouse embryo fibroblasts was selectively enhanced by consecutive cycloheximide-actinomycin D treatment, whereas without enhancement high numbers of IE1-IL cytolytic T lymphocytes were required to demonstrate the antigen in the IE phase. In the early phase of infection when IE genes were no longer transcribed, cytolysis was not observed, although IE proteins were detectable in the nuclei of the infected cells. Without application of inhibitors IE membrane antigen expression was most prominent during the late phase of infection. Reinitiation of transcription from the genomic region encoding the major IE protein (pp89) and de novo synthesis of pp89 correlated with this reexpression of the IE membrane antigen.

Animals↗

PubMed1986

Studies on the morphogenesis of murine cytomegalovirus.

Two modes of assembly of murine cytomegalovirus (MCMV) were observed in cultured mouse embryo fibroblasts, generating two morphologically different types of viral particles: monocapsid virions and multicapsid virions. The assembly of nucleocapsids appeared to be the same for both types of morphogenesis. Three successive stages of intranuclear capsid formation could be distinguished: capsids with electron-lucent cores, coreless capsids, and capsids with dense cores. Some of the capsids were enveloped at the inner nuclear membrane to form monocapsid virions, which were first detectable in the perinuclear cisterna. Other capsids left the nucleus via nuclear pores and usually entered cytoplasmic capsid aggregates that received an envelope by budding into extended cytoplasmic vacuoles, thereby forming multicapsid virions. Since the formation of multicapsid virions is not restricted to cell culture conditions and also occurs in vivo in immunosuppressed mice, multicapsid virions may play a role in the pathogenesis of cytomegalovirus infection.

Animals↗

PubMed1985

Interstitial murine cytomegalovirus pneumonia after irradiation: characterization of cells that limit viral replication during established infection of the lungs.

Interstitial pneumonia associated with viral replication in lung tissue was observed after cytomegalovirus infection of total-body gamma-irradiated mice, whereas in noncompromised hosts the lungs were not affected and virus multiplication was restricted to the salivary glands. The radiation damage could either predispose normally nonpermissive cell types for productive infection or abrogate an immune control of the tissue manifestation of infection by elimination of lymphocytes. Adoptive transfer of lymphoid cells into irradiated, infected recipients supported the second alternative. Even when infection was established in the lungs, as manifested by the presence of infected lung tissue cells in the alveolar septa, an antiviral effect could be assigned to the Lyt-2+, L3T4- subset of T lymphocytes specifically sensitized in the immunocompetent donor. These cells did not require in vitro propagation to perform effector cell functions in vivo and were operative under physiological conditions in comparatively low numbers. Hence, there is reason to assume that T lymphocytes are responsible for the tissue distribution of cytomegalovirus replication during infection.

Animals↗

PubMed1984

The cytolytic T lymphocyte response to the murine cytomegalovirus. II. Detection of virus replication stage-specific antigens by separate populations of in vivo active cytolytic T lymphocyte precursors.

During the acute cytolytic T lymphocyte (CTL) response of mice to infection with the murine cytomegalovirus two independent populations of activated interleukin-receptive CTL precursors can be demonstrated. One population is specific for cell membrane-incorporated viral structural antigens, whereas the second population detects an antigen, whose appearance is correlated with the synthesis of viral immediate early proteins. Since this new type of antigen is only defined by lymphocyte recognition, it is referred to as the lymphocyte-detected immediate early antigen (LYDIEA). Expression of immediate early antigen precedes the production of viral progeny and, therefore, it is possible that LYDIEA-specific CTL could serve as indicator cells for the very first activities of the viral genome, even during nonproductive infection.

Animals↗

PubMed1984

Frequency analysis of cytolytic T lymphocyte precursors (CTL-P) generated in vivo during lethal rabies infection of mice. II. Rabies virus genus specificity of CTL-P.

Cytolytic T lymphocyte precursors (CTL-P) were sensitized in vivo by intraplantar infection of C57BL/6 mice with a lethal dose of rabies virus, strain ERA (ERA). As a result of sensitization CTL-P matured to interleukin-receptive CTL-P (IL-CTL-P) that could be expanded in vitro to Thy-1+, Lyt-2+ CTL clones in the presence of IL without subjection to antigen-driven selection. After infection with ERA, IL-CTL-P-derived CTL lysed fibroblasts infected with rabies virus but not those infected with another rhabdovirus, the vesicular stomatitis virus. These CTL, however, did not discriminate between fibroblasts infected with the serologically closely related laboratory strains of classic rabies virus, ERA and HEP-Flury, and the serologically distinct rabies-related African isolate Mokola. This finding implies that in vivo sensitized IL-CTL-P recognize common genus-specific determinants expressed on cells infected with members of the lyssavirus genus.

Animals↗

PubMed1984

The cytolytic T lymphocyte response to the murine cytomegalovirus. I. Distinct maturation stages of cytolytic T lymphocytes constitute the cellular immune response during acute infection of mice with the murine cytomegalovirus.

Limiting dilution (LD) analysis with two modifications, the expansion and the restimulation LD assay, led to the detection and quantification of two distinct in vivo maturation stages within the lineage of virus-specific self-restricted CTL after infection of mice with the murine cytomegalovirus (MCMV). A low frequency set, representing an average of 15% of the specifically activated CTL-P in a draining lymph node, generated virus-specific lytic activity in the absence of antigen, solely under expansion conditions provided by growth and differentiation interleukins. These cells were considered to be active and were denoted antigen-independent or interleukin-receptive CTL-P (IL-CTL-P). A high frequency set required additional antigen in vitro to generate functionally active clones, and therefore the cells were termed antigen-dependent. Both sets are present in vivo simultaneously at the peak of the acute immune response and represent antigen-activated cells because their existence strictly depends on a preceding priming event. IL-CTL-P disappear quickly after acute infection and are absent during the memory state. It is proposed that the isolation of IL-CTL-P could serve to detect viral antigen expression during persistent and/or recurrent herpes virus infections.

Acute Disease↗

PubMed1982

Frequency analysis of cytolytic T cell precursors (CTL-P) generated in vivo during lethal rabies infection of mice. I. Distinction of CTL-P with different interleukin 2 sensitivity.

The aim of this study was to determine the number and state of activity of cytolytic T lymphocytes (CTL) and their precursors (CTL-P) present in vivo during the early stages of viral infection. The local response to lethal infection with rabies virus was used as a model system that is not accessible to analysis by secondary activation in vitro. The local response to alloantigen served as a control. Experimental protocols were established that allow frequency estimates of in vivo antigen-triggered CTL-P. Data allow a distinction between CTL-P activated in vivo by alloantigen and viral antigen with respect to their different capacity to utilize T cell growth factors (interleukins). In vivo alloantigen-primed CTL-P generate, in vitro, an active effector progeny in the presence of interleukins of xenogeneic origin, whereas the majority of virus-specific CTL-P, in spite of considerable expansion in vivo, fail to generate CTL in vitro unless antigen is added.

Animals↗

PubMedDate not supplied

Significance of herpesvirus immediate early gene expression in cellular immunity to cytomegalovirus infection.

Interstitial pneumonia linked with reactivation of latent human cytomegalovirus due to iatrogenic immunosuppression can be a serious complication of bone marrow transplantation therapy of aplastic anaemia and acute leukaemia. Cellular immunity plays a critical role in the immune surveillance of inapparent cytomegalovirus infections in man and the mouse. The molecular basis of latency, however, and the interaction between latently or recurrently infected cells and the immune system of the host are poorly understood. We have detected a so far unknown antigen in the mouse model. This antigen is found in infected cells in association with the expression of the herpesvirus 'immediate early' genes and is recognized by cytolytic T lymphocytes (CTL). We now demonstrate that an unexpectedly high proportion of the CTL precursors generated in vivo during acute murine cytomegalovirus infection are specific for cells that selectively synthesize immediate early proteins, indicating an immunodominant role of viral non-structural proteins.

Animals↗