Connective tissue growth factor expression in pediatric myofibroblastic tumors.

Human connective tissue growth factor (CTGF) is a secreted cysteine-rich peptide and a member of the peptide family that includes serum-induced immediate gene products such as a v-src-induced peptide and a putative proto-oncogene, c-src. CTGF is secreted by endothelial cells, fibroblasts, smooth muscle cells, and myofibroblasts. Its expression is increased in various human and animal fibrotic diseases. We hypothesized that tumors with significant fibrous and vascular components would exhibit increased expression of CTGF. We examined the expression of CTGF mRNA by in situ hybridization in 12 pediatric tumors and tumor-like conditions, including angiofibroma, malignant fibrous histiocytoma, infantile myofibromatosis, and malignant hemangiopericytoma. All the tumors showed moderate to intense CTGF expression in tumor cells and/or endothelial cells of the associated vasculature. Angiofibromas expressed CTGF only in factor VIII-positive endothelial cells and vascular smooth muscle cells. In contrast, infantile myofibromatosis, malignant hemangiopericytomas, and fibrous histiocytomas expressed CTGF in both endothelial cells and in vimentin-positive tumor cells, particularly those around the blood vessels. CTGF mRNA was not detected in the inflammatory cells observed in many of the tumors. The presence of CTGF in the endothelial cells and tumor cells around blood vessels raises the possibility that CTGF is involved in the pathogenesis of these myofibroblastic tumors.

Further observations on coronavirus infection of primate CNS.

Previously, we demonstrated that intracerebral (IC) inoculation of a murine coronavirus, MHV-JHM, into two species of primates can result in acute encephalomyelitis (Murray et al., 1992a). Infectious virus isolated from acutely infected animals, designated JHM-OMp1, was inoculated IC into a second group of monkeys. In this report we describe observations on the acutely infected animals and those surviving the acute infection were sacrificed at later times post-infection. Results from dual in situ hybridization/immunohistochemistry screening of tissues show that astrocytes are target cells in white matter lesions during acute infection. In animals sacrificed 150 days post-infection, areas of demyelinated gliotic lesions, prominent in the spinal cord, were seen throughout the neuraxis. No virus products were detected in these late-infection lesions.

Characterization of human T cell clones specific for coronavirus 229E.

Coronaviruses (CV) are pleomorphic enveloped RNA viruses that are ubiquitous in nature, causing a variety of diseases in both man and domestic animals. In man, CV are generally associated with upper respiratory tract infections. The two prototype strains that are the best studied human CV isolates and which are thought to be responsible for most of the respiratory infections caused by CV are called 229E and OC43. Humoral responses consisting of neutralizing antibodies to CV are present in most individuals by six years of age. Although the cellular immune response to CV in man has not been characterized at all, it is known that the spike (S) and nucleocapsid (N) proteins elicit the major cell mediated immune responses in the mouse. This report describes the production and characterization of eleven independently isolated T cell clones that are specific for the human CV(HCV) 229E. The T cell clones are CD4+ and presumably recognize a processed viral peptide presented by class II molecules on the surface of antigen presenting cells. Of six 229E-specific T cell clones tested against purified viral proteins, three recognize the 180 kD spike glycoprotein while the other three recognize the 55 kD nucleocapsid phosphoprotein. Analysis of the human T cell mediated response to HCV will provide information regarding which viral proteins elicit the immunodominant response, what the fine specificity of these T cell clones are (immuno-dominant peptides), and what the T cell receptor (TCR) and cytokine usage is of these virus specific clones.

In vitro interaction of coronaviruses with primate and human brain microvascular endothelial cells.

Primary human and primate brain microvascular endothelial cells were tested for permissiveness to coronaviruses JHM and 229E. While sub-genomic viral RNAs could be detected up to 72 hours post-infection, primate cells were abortively infected and neither virus caused cytopathology. Human cells were non-permissive for JHM but permissive for 229E replication; peak production of progeny 229E and observable cytopathic effects occurred approximately 22 and 32 hour post-infection, respectively. Using the criterion of cytopathology induction in infected endothelial cells, 229E was compared to other human RNA and DNA viruses. In addition, virus induced modulation of intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1) and HLA I was monitored by immunostaining of infected cells.

Entry of coronavirus into primate CNS following peripheral infection.

A previous report demonstrated that intracerebrally inoculated coronavirus produced CNS disease in two species of primates (Murray RS, Cai G-Y, Hoel K, et al., Virol 1992; 188: 274-84). We were therefore interested in testing the potential of coronaviruses to infect primate CNS tissue following peripheral inoculation. Four Owl monkeys (Aotus trivirgatus) were inoculated intranasally and ocularly and four were inoculated intravenously with coronavirus JHM OMp1 (Murray RS, Cai G-Y, Hoel K, et al., Virol 1992; 188: 274-84). Two intranasally and two intravenously inoculated animals received a second intravenous inoculum at 153 days post-infection. The animals were sacrificed 16, 35, 194, and 215 days post-infection. Tissue sections from brain and spinal cord were screened for viral products by in sity hybridization and immunostaining. Virus RNA and/or antigen was detected in the brains of all animals and the distribution corresponded to areas of inflammation and edema. Viral products were predominantly found in blood vessels and perivascular regions, suggesting hematogenous spread with entry into the central nervous system through endothelium.

Coronavirus JHM OMP1 pathogenesis in owl monkey CNS and coronavirus infection of owl monkey CNS via peripheral routes.

Two separate studies are described in this report. First, 5 Owl monkeys were inoculated intracerebrally (IC) with coronavirus JHM OMP1; this virus isolate was cultured from the brain of an animal inoculated with uncloned MHV JHM. Two of the animals became neurological impaired and were sacrificed; these animals had developed severe encephalomyelitis as previously described. Two of the remaining 3 healthy animals were inoculated IC again at 90 days post-inoculation (DPI) and all 3 were sacrificed approximately 5 months after the first virus inoculation. Despite the lack of detectable infectious virus, viral RNA and antigen, all 3 animals had significant white matter inflammation and areas of demyelination in the spinal cord. In the second study 4 Owl monkeys were inoculated intranasally (IN) and ocularly and 4 inoculated intravenously (i.v.) with JHM OMP1. The animals were sacrificed between 16 and 215 DPI with 2 IN and 2 i.v. animals receiving a second i.v. inoculum at 152 DPI. Viral RNA and/or antigen was detected in the brains of all animals and the distribution corresponded to areas of inflammation and edema. One of the animals that received the second inoculum developed neurological impairment and subsequent analysis of tissues showed viral antigen in both brain and spinal cord. Viral products were predominantly found in blood vessels suggesting hematogenous spread with entry into the central nervous system (CNS) through endothelium.

Search for evidence of herpes simplex virus, type 1, or varicella-zoster virus infection in postmortem brain tissue from schizophrenic patients.

The highly sensitive polymerase chain reaction (PCR) was used to search for herpes simplex virus type 1 (HSV-I) or varicella-zoster virus (VZV) in the DNA extracted from postmortem temporal cortex samples of 8 schizophrenic subjects, 8 nonschizophrenic suicide victims and 8 normal controls. HSV-I or VZV-specific DNA amplification was not detected in any of the samples studied.

Coronavirus infects and causes demyelination in primate central nervous system.

Two species of primates, Owl and African green monkeys, were inoculated intracerebrally with either the neurotropic mouse hepatitis virus JHM or the putative multiple sclerosis brain coronavirus isolate SD. These viruses caused an acute to subacute panencephalitis and/or demyelination in the infected animals. The course of pathogenesis and sites of detected viral RNA and antigen was dependent both on animal species and virus strain but the results clearly showed that these viruses replicated and disseminated in the central nervous system (CNS) of these primates. This study suggests that human CNS may be susceptible to coronavirus infection.

Detection of coronavirus RNA and antigen in multiple sclerosis brain.

Epidemiological studies of patients with multiple sclerosis (MS) and animal model data support the hypothesis that viruses initiate the immunopathogenic events leading to demyelination in MS. There have been no reports, however, of consistent detection of viruses in MS central nervous system tissue. We probed MS and control brain with cDNA probes specific for human, murine, porcine, and bovine coronaviruses. We report the in situ hybridization detection of coronavirus RNA in 12 of 22 MS brain samples using cloned coronavirus cDNA probes. In addition, tissue was screened for coronavirus antigen by immunohistochemical methods; antigen was detected in two patients with rapidly progressive MS. Significant amounts of coronavirus antigen and RNA were observed in active demyelinating plaques from these two patients. These findings show that coronaviruses can infect the human central nervous system and raise the possibility that these viruses may contribute to the pathogenesis of MS in some patients.

In-vitro synthesis of functional varicella zoster and herpes simplex viral thymidine kinase.

The varicella zoster virus (VZV) and herpes simplex virus type 1 (HSV-1) thymidine kinase (TK) genes were cloned into the transcription vector pGEM4. In-vitro translation (ivt) of RNA transcribed from these genes showed prominent expression of functional TK proteins with the expected molecular weights of 36 kD for VZV and 43, 39, and 38 kD for HSV-1. The TK proteins were recognized by rabbit anti-VZV and anti-HSV-1 antibodies, respectively. Analysis of the ivt products by thin-layer chromatography revealed the conversion of thymidine to its phosphorylated forms (TMP, TDP, and TTP) by both the VZV and HSV-1 TK genes. The estimated specific activities of the in-vitro translated VZV and HSV-1 TKs were comparable. VZV TK templates were linearized at internal restriction sites and RNAs transcribed from these templates directed the synthesis of polypeptides with sizes consistent with the colinearity of the VZV TK gene. Deletion of 107 amino acids at the carboxy terminus of the VZV TK gene abolished the in-vitro TK activity. In addition, immunoprecipitation of truncated proteins synthesized in vitro suggested the possible involvement of the region between amino acid residues 101 and 168 from the amino terminus of the VZV TK molecule in the formation of structures necessary for antigenicity.

Trans-activation of viral tk promoters by proteins encoded by varicella zoster virus open reading frames 61 and 62.

Plasmids containing the varicella zoster virus (VZV) open reading frames (ORFs) 61 and 62 were used in a transient co-transfection assay to test for trans-activation of the VZV and herpes simplex virus type 1 (HSV-1) thymidine kinase (tk) promoters. The trans-activating potential of the polypeptides encoded by these VZV ORFs, designated p51 and p140, was compared to that of their HSV-1 homologs ICP0 and ICP4, respectively. VZV p51 was functionally inactive in this system while p140 appeared to be a much stronger transcriptional activator than ICP4. Co-transfection of plasmids encoding VZV p140 and HSV-1 ICP0 resulted in a synergistic activation of the reporter gene as has been shown for the combination of ICP4 and ICP0.

Recognition of similar epitopes on varicella-zoster virus gpI and gpIV by monoclonal antibodies.

Two monoclonal antibodies, MAb43.2 and MAb79.0, prepared against varicella-zoster virus (VZV) proteins were selected to analyze VZV gpIV and gpI, respectively. MAb43.2 reacted only with cytoplasmic antigens, whereas MAb79.0 recognized both cytoplasmic and membrane antigens in VZV-infected cells. Immunoprecipitation of in vitro translation products with MAb43.2 revealed only proteins encoded by the gpIV gene, whereas MAb79.0 precipitated proteins encoded by the gpIV and gpI genes. Pulse-chase analysis followed by immunoprecipitation of VZV-infected cells indicated reactivity of MAb43.2 with three phosphorylated precursor species of gpIV and reactivity of MAb79.0 with the precursor and mature forms of gpI and gpIV. These results indicated that (i) MAb43.2 and MAb79.0 recognize different epitopes on VZV gpIV, (ii) glycosylation of gpIV ablates recognition by MAb43.2, and (iii) gpIV is phosphorylated. To map the binding site of MAb79.0 on gpI, the pGEM transcription vector, containing the coding region of the gpI gene, was linearized, and three truncated gpI DNA fragments were generated. RNA was transcribed from each truncated fragment by using SP6 RNA polymerase, translated in vitro in a rabbit reticulocyte lysate, and immunoprecipitated with MAb79.0 and human sera. The results revealed the existence of an antibody-binding site within 14 amino acid residues located between residues 109 to 123 on the predicted amino acid sequences of gpI. From the predicted amino acid sequences, 14 residues on gpI (residues 107 to 121) displayed a degree of similarity (36%) to two regions (residues 55 to 69 and 245 to 259) of gp IV. Such similarities may account for the binding of MAb79.0 to both VZV gpI and gpIV.

Regulation of varicella zoster virus gene 27 translation in vitro by upstream sequences.

Northern blot analysis revealed the presence of varicella-zoster virus (VZV) gene 27 transcripts in infected cells. The Sal I-G DNA fragment, located in the unique long segment of the VZV genome and containing overlapping genes 26 and 27, was analyzed in an in vitro transcription-translation system. Translation of RNA transcribed from these open reading frames showed prominent expression of gene 27. Four different subclones were constructed to contain gene 27 with and without 100 base pairs (bp) of upstream sequences. Translation of RNA from these constructs using wheat germ extract or rabbit reticulocyte lysate indicated that the sequences upstream from the predicted initiation codon (AUG) of gene 27 downregulated the expression of this gene at the level of translation and that the predicted AUG within gene 27 was preferentially used.

Expression of varicella-zoster virus glycoprotein I in cells infected with a vaccinia virus recombinant.

BSC-1 cells infected with a vaccinia virus recombinant containing the coding sequences for varicella-zoster virus (VZV) glycoprotein I (gpI) were analyzed by indirect immunofluorescence and immunoprecipitation for the expression and processing of gpI. The processing of gpI in cells infected with recombinant virus was the same as that observed during VZV infection. Immunofluorescence revealed localization of gpI to the membranes of recombinant virus-infected cells.

Transcriptional mapping of early RNA from regions of the Shope fibroma and malignant rabbit fibroma virus genomes.

Malignant rabbit fibroma virus (MV) is a recombinant poxvirus derived from Shope fibroma virus (SFV) and rabbit myxoma virus (D. S. Strayer, E. Skaletsky, G. F. Cabirac, P. A. Sharp, L. B. Corbeil, S. Sell, and J. L. Leibowitz, 1983a, J. Immunol. 130, 399-404; W. Block, C. Upton, and G. McFadden, 1984, Virology 140, 113-124). We report here the transcriptional mapping of early RNAs transcribed from the SFV sequences within MV and from the corresponding regions in SFV. Hybridization analysis and S1 nuclease mapping of RNA using viral DNA probes were used to define 5' and 3' ends of the various transcripts. The RNAs described here are transcribed in one direction in a densely arranged head to tail fashion similar to that described for some vaccinia virus early transcriptional units. At late times of infection the early SFV RNAs are not detected whereas the early MV RNAs are present in minor amounts. The early SFV and MV transcripts range in size from 3170 to 425 nucleotides (nt) long. All of the longer transcripts are produced as a result of read through transcription. Three MV transcripts contain fused SFV and rabbit myxoma virus sequences due to transcription through the recombination junction region in the MV genome. Two other MV transcripts are transcribed from a unique initiation site near another recombination junction region resulting in RNAs that are composed of SFV sequences having unique 5' ends.

Leporine acquired immune deficiency disease.

We have identified a recombinant leporipoxvirus that produces disseminated fibromas and a severe combined immune deficiency disease of sudden onset. The virus is recombinant between the SFV and the MV. MV was identified as a trace contaminant in stocks of SFV (Patuxent strain). Rabbits inoculated with the original uncloned stock of SFV prepared in vitro develop local tumors that subsequently regress. However, tumor extracts prepared from these animals, when injected into a second group of rabbits, produced MV syndrome. Rabbits with MV syndrome develop severe, usually lethal, Pasteurella or Bordetella infections and have disseminated fibroxanthosarcomas more similar to those produced by myxoma virus. The virus that induces this syndrome has been isolated by two cycles of plaque purification. This virus is indistinguishable from SFV using cross-neutralization and electron microscopy. Analyses of restriction enzyme digests of MV and plaque-purified SFV show them to be quite dissimilar and indicate that MV is recombinant between SFV and myxoma virus. This recombinational event resulted in approximately 5.5 kb of myxoma virus DNA within each of the inverted terminal repeats being replaced by a similar amount of DNA derived from the corresponding region of the SFV genome. Thus, MV contains approximately 149 kb of myxoma sequences and 11 kb of SFV sequences. Immunofluorescent studies of spleen and lymph nodes from MV-infected rabbits demonstrate that viral antigens are present predominantly in the sinusoidal lining cells in lymph nodes and in phagocytes in the splenic cords. This contrasts with the distribution of antigen observed in myxoma virus-infected rabbits where myxoma-specific antigens are present in large amounts in hyperplastic epithelium overlying tumors, particularly in the nasal mucosa and in spleen and lymph node cells. MV-infected rabbits essentially lose their lymphocyte proliferative response to T and B cell mitogens and are unable to initiate an antibody response to SRBC, as determined by a modified Jerne plaque assay. In vitro MV severely depresses the mitogen responses of normal B and T lymphocytes after two days of culture. Lymphoid cells and lysates of lymphoid cells from MV-infected rabbits will suppress mitogen- and antigen-induced responses in vitro. MV can grow in lymphocytes, but replication of MV is less efficient in lymphocytes than in RK-13 cells. Thus, MV produces a disseminated viral infection, systemic myxofibromas, and a severe combined immune deficiency in rabbits. The molecular and immunologic basis for these effects is now under study.