In Vivo Efficacy of Measles Virus Fusion Protein-Derived Peptides Is Modulated by the Properties of Self-Assembly and Membrane Residence.

Measles virus (MV) infection is undergoing resurgence and remains one of the leading causes of death among young children worldwide despite the availability of an effective measles vaccine. MV infects its target cells by coordinated action of the MV hemagglutinin (H) and fusion (F) envelope glycoproteins; upon receptor engagement by H, the prefusion F undergoes a structural transition, extending and inserting into the target cell membrane and then refolding into a postfusion structure that fuses the viral and cell membranes. By interfering with this structural transition of F, peptides derived from the heptad repeat (HR) regions of F can inhibit MV infection at the entry stage. In previous work, we have generated potent MV fusion inhibitors by dimerizing the F-derived peptides and conjugating them to cholesterol. We have shown that prophylactic intranasal administration of our lead fusion inhibitor efficiently protects from MV infection in vivo We show here that peptides tagged with lipophilic moieties self-assemble into nanoparticles until they reach the target cells, where they are integrated into cell membranes. The self-assembly feature enhances biodistribution and the half-life of the peptides, while integration into the target cell membrane increases fusion inhibitor potency. These factors together modulate in vivo efficacy. The results suggest a new framework for developing effective fusion inhibitory peptides. IMPORTANCE: Measles virus (MV) infection causes an acute illness that may be associated with infection of the central nervous system (CNS) and severe neurological disease. No specific treatment is available. We have shown that fusion-inhibitory peptides delivered intranasally provide effective prophylaxis against MV infection. We show here that specific biophysical properties regulate the in vivo efficacy of MV F-derived peptides.

Suppression of Smad-1 mRNA expression level by Smad-2 likely control dichotomy of NF-κB and Smads mediated activation.

The aim of this study was to find out how NF-κB and Smad-mediated signaling influenced the expression of astrogliogenic versus neurogenic markers of brain development in U4C cells which were either enriched (Tg Jak-1) or deprived in Jak-1 molecule (Jak-1 KO). Genetically modified U4C cells were transfected with NF-kB reporter plasmid in order to follow its activation when cells were cotransfected with different combinations of Smads constructs. In wild type cells no significant activation of NF-κB was observed while genetically modified cells exhibited somewhat different pattern of NF-κB activation depending on the Smad constructs combination used. The absence of NF-κB activation in Jak-1 transgenic cells transfected with Smad-1 plus Smad-3 was accompanied by the appearance of apoptotic cells as revealed by DAPI staining. Smad-1 expression was undetectable in Jak-1 transgenic cells and was downregulated in wild type cells upon transfection with Smad-2. The absence of p65 nuclear translocation in Smad-2 transfected cells and the presence of Smad-4 in nucleus of the same cells indicates dichotomy in NF-κB and Smads mediated signaling pathways. The significance of this study is that helps to elucidate the point of collaboration among three different signaling pathways - Jak-1 mediated cytokine signaling, NF-κB and Smads mediated pathways.

Prevention of measles virus infection by intranasal delivery of fusion inhibitor peptides.

UNLABELLED: Measles virus (MV) infection is undergoing resurgence and remains one of the leading causes of death among young children worldwide despite the availability of an effective measles vaccine. MV infects its target cells by coordinated action of the MV H and the fusion (F) envelope glycoprotein; upon receptor engagement by H, the prefusion F undergoes a structural transition, extending and inserting into the target cell membrane and then refolding into a postfusion structure that fuses the viral and cell membranes. By interfering with this structural transition of F, peptides derived from the heptad-repeat (HR) regions of F can potently inhibit MV infection at the entry stage. We show here that specific features of H's interaction with its receptors modulate the susceptibility of MV F to peptide fusion inhibitors. A higher concentration of inhibitory peptides is required to inhibit F-mediated fusion when H is engaged to its nectin-4 receptor than when H is engaged to its CD150 receptor. Peptide inhibition of F may be subverted by continued engagement of receptor by H, a finding that highlights the ongoing role of H-receptor interaction after F has been activated and that helps guide the design of more potent inhibitory peptides. Intranasal administration of these peptides results in peptide accumulation in the airway epithelium with minimal systemic levels of peptide and efficiently prevents MV infection in vivo in animal models. The results suggest an antiviral strategy for prophylaxis in vulnerable and/or immunocompromised hosts. IMPORTANCE: Measles virus (MV) infection causes an acute illness that may be associated with infection of the central nervous system (CNS) and severe neurological disease. No specific treatment is available. We have shown that parenterally delivered fusion-inhibitory peptides protect mice from lethal CNS MV disease. Here we show, using established small-animal models of MV infection, that fusion-inhibitory peptides delivered intranasally provide effective prophylaxis against MV infection. Since the fusion inhibitors are stable at room temperature, this intranasal strategy is feasible even outside health care settings, could be used to protect individuals and communities in case of MV outbreaks, and could complement global efforts to control measles.

Current animal models: transgenic animal models for the study of measles pathogenesis.

Animal models are highly important to understand the pathologic mechanisms of viral diseases. Therefore, the lack of a suitable animal model has greatly hindered the research into the pathogenesis of measles. Identification of two human receptors for measles virus, CD46 and CD150 (SLAM) has opened new perspectives in this field. During the last decade, numerous transgenic animal models have been developed in order to humanize mice and use them to study measles infection and virus-host interactions. Despite their limitations, these models have provided remarkable insights in different aspects of measles infection, providing a better understanding of virus-induced neuropathology, immunosuppression, mechanisms of virus virulence, and contribution of innate and adaptive immune response in viral clearance. They should certainly continue to help in studies of the host and viral factors that are important in measles infection and in developing of new antiviral agents and measles virus-based vaccines. In addition, as CD46 serves as a receptor for two other human viruses, some of these models may also find an important application in the study of adenovirus and herpesvirus 6 infection. In this review, we describe different CD46 and CD150 transgenic models and detail their utilization in the study of various aspects of measles pathogenesis.

[Nipah and Hendra viruses : emerging zoonotic pathogens]. / Les virus Nipah et Hendra : des agents pathogènes zoonotiques émergents.

Emerging new viruses present an enormous challenge in understanding their aetiology, pathogenesis and epidemiology. In the last decade two new viruses : Nipah virus in Malaysia and Hendra virus in Australia crossed species barrier from flying foxes to infect humans. While Hendra virus mainly induced pulmonary disease, Nipah virus provoked encephalitis with 40-70 % of mortality, causing important health and economic problems. Based on the similar genome structure, these 2 viruses are classified in a new genus, Henipaviruses, within the family of Paramyxoviridae and both are ranked internationally as biosecurity level 4 agents. Recent studies on the virulence, host range and cell tropism of these human pathogens provide more insight into unique biological properties of the emergent zoonotic viruses.

Mechanism of measles virus-induced suppression of inflammatory immune responses.

Measles virus (MV) causes profound immunosuppression, resulting in high infant mortality. The mechanisms are poorly understood, largely due to the lack of a suitable animal model. Here, we report that particular MV proteins, in the absence of MV replication, could generate a systemic immunosuppression in mice through two pathways: (1) via MV-nucleoprotein and its receptor FcgammaR on dendritic cells; and (2) via virus envelope glycoproteins and the MV-hemagglutinin cellular receptor, CD46. The effects comprise reduced hypersensitivity responses associated with impaired function of dendritic cells, decreased production of IL-12, and the loss of antigen-specific T cell proliferation. These results introduce a novel model for testing the immunosuppressive potential of anti-measles vaccines and reveal a specific mechanism of MV-induced modulation of inflammatory reactions.

Octamerization enables soluble CD46 receptor to neutralize measles virus in vitro and in vivo.

A chimeric fusion protein encompassing the CD46 ectodomain linked to the C-terminal part of the C4b binding protein (C4bp) alpha chain (sCD46-C4bpalpha) was produced in eukaryotic cells. This protein, secreted as a disulfide-linked homo-octamer, was recognized by a panel of anti-CD46 antibodies with varying avidities. Unlike monomeric sCD46, the octameric sCD46-C4bpalpha protein was devoid of complement regulatory activity. However, sCD46-C4bpalpha was able to bind to the measles virus hemagglutinin protein expressed on murine cells with a higher avidity than soluble monomeric sCD46. Moreover, the octameric sCD46-C4bpalpha protein was significantly more efficient than monomeric sCD46 in inhibiting virus binding to CD46, in blocking virus induced cell-cell fusion, and in neutralizing measles virus in vitro. In addition, the octameric sCD46-C4bpalpha protein, but not the monomeric sCD46, fully protected CD46 transgenic mice against a lethal intracranial measles virus challenge.

Productive measles virus brain infection and apoptosis in CD46 transgenic mice.

Measles virus (MV) infection causes acute childhood disease, associated in certain cases with infection of the central nervous system (CNS) and development of neurological disease. To develop a murine model of MV-induced pathology, we generated several lines of transgenic mice ubiquitously expressing as the MV receptor a human CD46 molecule with either a Cyt1 or Cyt2 cytoplasmic tail. All transgenic lines expressed CD46 protein in the brain. Newborn transgenic mice, in contrast to nontransgenic controls, were highly sensitive to intracerebral infection by the MV Edmonston strain. Signs of clinical illness (lack of mobility, tremors, and weight loss) appeared within 5 to 7 days after infection, followed by seizures, paralysis, and death of the infected animals. Virus replication was detected in neurons from infected mice, and virus was reproducibly isolated from transgenic brain tissue. MV-induced apoptosis observed in different brain regions preceded the death of infected animals. Similar results were obtained with mice expressing either a Cyt1 or Cyt2 cytoplasmic tail, demonstrating the ability of different isoforms of CD46 to function as MV receptors in vivo. In addition, maternally transferred immunity delayed death of offspring given a lethal dose of MV. These results document a novel CD46 transgenic murine model where MV neuronal infection is associated with the production of infectious virus, similarly to progressive infectious measles encephalitis seen in immunocompromised patients, and provide a new means to study pathogenesis of MV infection in the CNS.

Somatostatin-dependent adenylyl cyclase activity in nonactivated and mitogen-activated human T cells: evidence for uncoupling of sst3 receptor from adenylyl cyclase.

Neuropeptide somatostatin (SRIF) has been shown to modulate interleukin-2 (IL-2) secretion by mitogen-activated T cells. In this study, we further analyzed the transduction pathways underlying SRIF actions on human Jurkat T cells and compared SRIF signaling between nonactivated and mitogen-activated cells. SRIF effects on adenylyl cyclase activity in the absence and presence of mitogens were addressed by using three different analogs: SRIF14, SRIF28, and SMS 201-995. In semipurified membrane preparations obtained from nonactivated cells, all analogs inhibited adenylyl cyclase. However, in membrane preparations obtained from mitogen-activated cells, the maximal inhibition of adenylyl cyclase mediated by SRIF14 and SRIF28 equaled only one third of that measured in the absence of mitogens, whereas SMS 201-995 was completely inactive. To assess the relevant mechanisms associated with different effects of SRIF on adenylyl cyclase activity in nonactivated and mitogen-activated T cells, we performed binding assays by using iodinated SRIF as a radioligand. These experiments suggested that both the number of receptors and their affinities were almost identical in either nonactivated or activated cells. RT-PCR analysis of the pattern of SRIF receptor expression showed that nonactivated as well as activated Jurkat cells expressed only mRNA corresponding to the sst3 receptor subtype. Altogether, these data point to a functional activation-associated uncoupling of sst3 receptors from adenylyl cyclase in human T cells, indicating a T-cell activation-induced alteration in the sst3 receptor transduction pathway.

Measles virus infection induces terminal differentiation of human thymic epithelial cells.

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 from low- to high-molecular-weight keratin expression. Measles virus infection induces thymic epithelial cell apoptosis in terminally differentiated cells, revealed by the condensation and degradation of DNA in measles virus-infected floating thymic epithelial cells. Because thymic epithelial cells are required for the generation of immunocompetent T lymphocytes, our results suggest that measles virus-induced terminal differentiation of thymic epithelial cells may contribute to immunosuppression, particularly in children, in whom the thymic microenvironment is of critical importance for the development and maturation of a functional immune system.

Enhanced MHC class II-restricted presentation of measles virus (MV) hemagglutinin in transgenic mice expressing human MV receptor CD46.

This study analyzes the role of the measles virus (MV) receptor, i.e. the human CD46 molecule, in the MHC class II-restricted presentation of MV hemagglutinin (H). We generated transgenic mice ubiquitously expressing CD46, with a similar level of transgene expression on the surface of antigen-presenting cells (APC), i.e. B cells, dendritic cells (DC) and macrophages. APC isolated from transgenic mice and nontransgenic controls were tested for their ability to present MV H to H-specific CD4+ I-Ed-restricted T cell hybridomas. All three populations of APC were capable of presenting MV to T cell hybridomas, DC being the most efficient. Expression of CD46 on B lymphocytes increased MHC class II-dependent presentation of MV H up to 100-fold, while CD46-transgenic DC stimulated H-specific T cell hybridomas up to 10-fold better than nontransgenic DC. Interestingly, expression of CD46 did not change the presentation efficiency of transgenic macrophages, indicating that CD46-dependent enhancement of antigen presentation depends on the nature of the APC. Furthermore, a single injection of UV-inactivated MV particles into CD46-transgenic mice, but not nontransgenic controls, induced generation of MV-specific T lymphocytes and production of anti-H antibodies, suggesting a role for CD46 in the efficient capture of MV in vivo. These results show for the first time that one ubiquitously expressed cell surface receptor, like CD46, could function in receptor-mediated antigen presentation both in vitro and in vivo and its performance depends on the type of APC which expresses it.

Somatostatin increases mitogen-induced IL-2 secretion and proliferation of human Jurkat T cells via sst3 receptor isotype.

The neuropeptide somatostatin (SRIF) modulates normal and leukemia T cell proliferation. However, neither molecular isotypes of receptors nor mechanisms involved in these somatostatin actions have been elucidated as yet. Here we show by using RT-PCR approach that mitogen-activated leukemia T cells (Jurkat) express mRNA for a single somatostatin receptor, sst3. This mRNA is apparently translated into protein since specific somatostatin binding sites (K11 = 78 +/- 3 pM) were detected in semipurified plasma membrane preparations by using 125I-Tyr1-SRIF14 as a radioligand. Moreover, somatostatin inhibits adenylyl cyclase activity with similar efficiency (IC50 = 23 +/- 4 pM) thus strongly suggesting a functional coupling of sst3 receptor to this transduction pathway. The involvement of sst3 receptor in immuno-modulatory actions of somatostatin was assessed by analysis of neuropeptide effects on IL-2 secretion and on proliferation of mitogen-activated Jurkat cells. Our data show that in the concentrations comprised between 10 pM and 10 nM, somatostatin potentiates IL-2 secretion. This effect is correlated with somatostatin-dependent increase of Jurkat cell proliferation since the EC50 concentrations for both actions were almost identical (EC50 = 22 +/- 9 pM and EC50 = 12 +/- 1 pM for IL-2 secretion and proliferation, respectively). Altogether, these data strongly suggest that in mitogen-activated Jurkat cells, somatostatin increases cell proliferation through the increase of IL-2 secretion via a functional sst3 receptor negatively coupled to the adenylyl cyclase pathway.

Transgenic expression of a CD46 (membrane cofactor protein) minigene: studies of xenotransplantation and measles virus infection.

CD46 (membrane cofactor protein) is a human cell-surface regulator of activated complement and a receptor for the measles virus. A CD46 transgenic mouse line with an expression pattern similar to that of human tissues has been produced, to develop an animal model of (i) the control of complement activation by complement regulators in hyperacute rejection of xenografts, and (ii) measles virus infection. The mouse line was made using a CD46 minigene that includes promoter sequence and the first two introns of genomic CD46, which was coinjected into mouse ova with chicken lysozyme matrix attachment region DNA. A high level of CD46 expression in homozygotic transgenic mice was obtained with spleen cells having approximately 75% of the level found on human peripheral blood mononuclear cells. CD46 was detected in all tissues examined by immunohistochemistry, radioimmunoassay and Western blotting, showing that these mice were suitable for transplantation and measles virus infection studies. It also indicated that the transgene included the important regulatory elements of the CD46 promoter. Transgenic spleen cells were significantly protected in vitro from human complement activated by either the classical or alternative pathways and from alternative pathway rat complement. Furthermore, transgenic mouse hearts transplanted to rats regulated complement deposition in an in vivo model of antibody-dependent hyperacute xenograft rejection. Similar to human lymphocytes, transgenic lymphoblasts could be infected in vitro with measles virus; infected cells expressed viral proteins and produced infectious viral particles. The data demonstrate the suitability of this minigene for obtaining high-level CD46 expression sufficient for enhanced resistance of transgenic cells to complement attack and for obtaining wide tissue distribution of CD46, analogous to human tissues and, therefore, useful for comparative studies.

Transgenic mice expressing human measles virus (MV) receptor CD46 provide cells exhibiting different permissivities to MV infections.

We have generated transgenic mice ubiquitously expressing the human receptor for measles virus (MV), CD46 (membrane cofactor protein). Various cell types were isolated from these transgenic mice and analyzed for their ability to support MV replication in vitro. Although MV could enter into all CD46-expressing cells, differential susceptibilities to MV infection were detected depending on the cell type. Cell cultures obtained from transgenic lungs and kidneys were found to be permissive of MV infection, since RNA specific for MV genes was detected and viral particles were released, although at a low level. Similarly to human lymphocytes, activated T and B lymphocytes isolated from transgenic mice could support MV replication; virus could enter, transcribe viral RNA, and produce new infectious particles. When expressing viral proteins, lymphocytes down-regulated CD46 from the surface. Interestingly, while activated T lymphocytes from nontransgenic mice did not support MV infection, activated nontransgenic murine B lymphocytes replicated MV as well as transgenic B lymphocytes, suggesting the use of an alternative virus receptor for entry. In contrast to the previous cell types, murine peritoneal and bone marrow-derived macrophages, regardless of whether they were activated, could not support MV replication. Furthermore, although MV entered into macrophages and virus-specific RNA transcription occurred, no virus protein or infectious virus particles could be detected. These results show the importance of the particular cell-type-specific host factors for MV replication in murine cells which may be responsible for the differential permissivity of MV infection.

T cell development in TCR-alpha beta transgenic mice. Analysis using V(D)J recombination substrates.

The major pathway of intrathymic T cell differentiation leads CD4-8- (DN) T lineage-committed precursors to TCR-alpha beta+ CD4+8- or CD4-84+ (SP) T lymphocytes. The expression of functionally rearranged TCR-alpha beta transgenes (Tg-TCR) may influence thymocyte development by affecting the various selection events that control T cell differentiation. To gain insights into these processes, we have produced double transgenic animals carrying V(D)J recombination substrates in addition to the MHC class I (H-2Kb) allospecific KB5C20 Tg-TCR. We have analyzed substrate rearrangements in purified populations of Tg-TCR+ thymocytes in the situation of positive or negative selection. The profile of rearrangements found in SP thymocytes, positively selected for the Tg-TCR, suggests that expression of the KB5C20 Tg-TCR has only a minimal influence on substrate V(D)J recombination in cells differentiating along the major alpha beta T cell developmental pathway. In contrast, Tg-TCR+ DN thymocytes, in both positively and negatively selecting haplotypes, presented a profile that implies premature cessation of substrate rearrangements. This profile was maintained in peripheral Tg-TCR+ DN cells and was distinct from the one found in CD25+, alpha beta+, or gamma delta+ DN cells purified from mice transgenic for the recombination substrates only. These results are discussed with respect to the possible origin and differentiation pathway of Tg-TCR+ DN and SP cells.

TCR beta and TCR alpha gene enhancers confer tissue- and stage-specificity on V(D)J recombination events.

We describe transgenic mice carrying germline variable gene segments associated with either the T cell receptor (TCR) beta or alpha gene enhancers (E beta or E alpha). Transgenic constructs underwent high rates of site-specific rearrangements predominantly in T cells from independent mice. Rearrangements of the E beta-containing transgenes began at different stages of T cell differentiation in embryonic and adult thymus than did the E alpha-containing ones, with a pattern superimposable upon the patterns of TCR beta or TCR alpha gene expression, respectively. We demonstrate that sequences within the TCR beta and TCR alpha gene enhancers confer tissue- and stage-specificity upon the V(D)J recombination events affecting adjacent gene segments. The patterns of transgene expression also gave information on developmental events and lineage relationships (gamma delta versus alpha beta) during T cell development.

Glycoproteins of mouse vaginal epithelium: differential expression related to estrous cyclicity.

We used lectin overlay blotting and SDS-PAGE to analyze the estrous cycle-specific expression of mouse vaginal epithelial glycoproteins. Seven lectins chosen for their differential carbohydrate-binding specificity revealed 15 glycoproteins that showed cycle-related expression. Each lectin had a unique binding pattern different from the patterns revealed by other lectins. However, several estrous cycle phase-specific glycoproteins reacted with more than one lectin. The most prominent of these glycoproteins (M(r) 92-95 KD) was weakly expressed in late diestrus and fully expressed only in proestrus, coincident with the transformation of two superficial layers of vaginal squamous epithelium into mucinous cuboidal cells. Electron microscopic lectin histochemistry revealed the glycoproteins in the mucinous granules of surface cuboidal cells and in the lumen of the vagina. Our results illustrate the complexity of glycoconjugate synthesis in mouse vagina and reveal the distinct cycle-specific patterns of individual glycoprotein expression. These cyclic glycoproteins could serve as vaginal biochemical markers for the specific phases of the estrous cycle.

Retinoic acid-induced differentiation of the developmentally pluripotent human germ cell tumor-derived cell line, NCCIT.

BACKGROUND: Germ cell tumors are empirically divided into seminomas and nonseminomatous germ cell tumors (NSGCT). Some authorities consider seminomas to be the precursors of NSGCT, whereas others consider them as distinct and unrelated neoplasms. Here, we report that the human NSGCT-derived stem cell line, NCCIT has hybrid features of seminoma and embryonal carcinoma, and suggest that this cell line could be useful for studying the relationship of seminoma to NSGCT. EXPERIMENTAL DESIGN: NCCIT, a developmentally pluripotent permanent cell line derived from a mediastinal NSGCT was karyotyped and characterized morphologically, immunochemically, and biochemically. The cells were grown under standard tissue culture conditions and were also exposed to retinoic acid to induce differentiation. RESULTS: The dividing NCCIT stem cell populations consist of vimentin-positive, keratin-negative cells that do not express desmoplakin or cadherin E (uvomorulin) and are not interconnected with one another. These cells have a high nucleocytoplasmic ratio and contain few cytoplasmic organelles, except for free ribosomes and a small number of mitochondria. Lacto- and globoseries oligosaccharide antigens recognized with antibodies to murine stage specific antigens 1, 3 and 4 (SSEA-1, SSEA-3 and SSEA-4), and human teratocarcinoma mucin-like antigen TRA-1-60 and TRA-1-81 are coexpressed on the cell membranes of a considerable number of stem cells. On most cells alkaline phosphatase can be detected by enzyme histochemistry. The placental isoenzyme of alkaline phosphatase was demonstrated by Western blotting in cell extracts. The liver/bone/kidney isoenzyme of alkaline phosphatase is immunochemically detected on 40% of cells. The culture supernatants also contain chorionic gonadotropin and alpha-fetoprotein, presumably derived from trophoblastic and yolk sac-like cells. The cells are hyperdiploid (chromosome range from 54 to 64) and show prominent structural chromosomal aberrations, mostly deletions and isochromosomes. Retinoic acid treatment inhibited the growth of NCCIT cells and induced stem cell differentiation into keratin, glial fibrillary acid protein, and neurofilament-positive somatic cells. The differentiation was associated with the disappearance of oligosaccharide surface antigens typical of the undifferentiated stem cells; a loss of proteins typical of undifferentiated cells and the appearance of new proteins; and the deposition of extracellular matrix. CONCLUSIONS: NCCIT is a developmentally pluripotent cell line that can differentiate into derivatives of all three embryonic germ layers (i.e., ectoderm, mesoderm, and endoderm) and extraembryonic cell lineages. We suggest that this cell line could be a malignant replica of human cleavage stage embryonic cells with features intermediate between seminoma and embryonal carcinoma.

Galactose-binding lectins as markers of pregnancy-related glycoproteins.

Protein extracts from pregnant mouse endometria were compared with those obtained from non-pregnant and pseudopregnant mice to detect early pregnancy-specific galactose-rich glycoproteins. Gradient gel electrophoresis combined with lectin overlay and lectin histochemistry were used to identify Ricinus communis I (RCA-I), R. communis II (RCA-II) and Cytisus scoparius (CSA) lectin binding glycoproteins. Using this approach, galactose-rich glycoproteins were identified that were maximally expressed in the estrus phase of non-pregnant endometria and also those that had peak expression in pregnancy. Lectin histochemistry revealed pregnancy related changes in three portions of mouse endometrium: endometrial glands, luminal epithelium and its basement membrane. Two major glycoproteins (RCA-I reactive 64 kDa and RCA-II reactive 35 kDa) were specifically expressed in peri-implantation endometrium on days 3 and 4 of pregnancy. The appearance of these glycoproteins during the period of the implantation window in mouse suggests that they could serve as markers of uterine receptivity to the implanting blastocyst.

Estrous-cycle-related changes in the expression of mouse endometrial and oviductal glycoproteins.

Glycoproteins of mouse endometrium and oviduct were analyzed by lectin overlay blotting of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE)-separated whole-cell extracts, sampled at each of the four phases of the normal estrous cycle. Nine endometrial and 5 oviductal glycoproteins were found only in one of these two organs or showed cyclic changes in their expression as revealed by wheat germ or Ricinus communis I lectin blotting. Glycoproteins of the same molecular weight showed different expressions in the endometrium as compared with the oviduct. Thus one can conclude that the expression of the endometrial and oviductal glycoproteins is cyclic, but organ specific.