Amount of viral DNA in the genome of cells transformed by adenovirus type 2

Encounters with adenovirus

In this paper I describe aspects of work on the human adenoviruses in which my laboratory has participated. It consists of two sections-one historic dealing with work performed in the previous century, and one dealing with the application of 'omics' technologies to understand how adenovirus-infected cells become reprogrammed to benefit virus multiplication.

Proteome analysis of adenovirus using mass spectrometry

Analysis of proteins and their posttranslational modifications is important for understanding different biological events. For analysis of viral proteomes, an optimal protocol includes production of a highly purified virus that can be investigated with a high-resolving analytical method. In this Methods in Molecular Biology paper we describe a working strategy for how structural proteins in the Adenovirus particle can be studied using liquid chromatography-high-resolving mass spectrometry. This method provides information on the chemical composition of the virus particle. Further, knowledge about amino acids carrying modifications that could be essential for any part of the virus life cycle is collected. We describe in detail alternatives available for preparation of virus for proteome analysis as well as choice of mass spectrometric instrumentation suitable for this kind of analysis.

Photochemical treatment with endosomally localized photosensitizers enhances the number of adenoviruses in the nucleus

BACKGROUND

In the present study the physical targeting technique photochemical internalization (PCI) has been used in combination with adenovirus. We have previously shown that PCI enhances transgene expression from AdhCMV-lacZ, and the aim of the present study was to further increase the understanding of photochemically mediated adenoviral transduction.

METHODS

Two colorectal carcinoma cell lines, WiDr and HCT116, were pre-incubated with the photosensitizer TPPS(2a) or methylene blue derivates (MBD) followed by infection with adenovirus and light exposure. Transgene expression was measured by flow cytometry. Real-time polymerase chain reaction (PCR) and fluorescence in situ hybridization (FISH) were used to quantify the level of viral DNA in the nuclei. Real-time PCR was also used to measure the level of beta-galactosidase mRNA in samples infected with AdhCMV-lacZ.

RESULTS

Exposing TPPS(2a)-treated cells to light enhanced the quantity of viral DNA in the nucleus, the mRNA level of the transgene and the transgene expression compared to non-illuminated cells. The increased transgene expression was independent of the promoter used, but dependent on the time of light exposure and the cellular localization of the photosensitizer.

CONCLUSIONS

The enhanced transgene expression observed after photochemical treatment is most likely not a result of one event, but more an interplay between various mechanisms. An increased level of adenoviral DNA in the nucleus and a dependency of endosomal localization of the photosensitizer to obtain enhanced transgene expression suggested that endosomal rupture facilitated the transport of adenoviruses to the nucleus.

Human adenovirus type 35: nucleotide sequence and vector development

In this report, we describe the complete 34,794 base pair genomic sequence of the human adenovirus serotype 35 (Ad35) Holden strain. The viral genome exhibits a compact organization similar to other adenoviral serotypes, with overlapping genes on both strands. In all, 47 open reading frames (ORFs) were identified, including early (E1, 2, 3, 4) and late (L1, 2, 3, 4, 5) regions conserved among the adenoviridae family. In addition, 14 ORFs were identified that do not encode known adenoviral genes. Comparison of the predicted translational products of the conserved genes with those of other adenoviruses revealed that Ad35 has high homology to Ad7, Ad3, Ad21, Ad17, and simian Ads25. Based on the complete Ad35 DNA sequence, E3-, E1-, and E1/E3-deleted Ad35-based vector systems were developed. An HEK293-derived cell line was established for the propagation of the E1-deleted Ad35 vector, avoiding the emergence of replication-competent adenovirus. Moreover, production of the E1-deleted recombinant Ad35 vector was achieved by transient transduction of a plasmid encoding the Ad35 E1B gene in HEK293 cells. Testing showed that the Ad35-based vector efficiently infects both human and rhesus macaque dendritic cells. Our novel Ad35-based vectors and their corresponding packaging cell lines will provide a versatile and powerful system for DNA-based vaccine development and gene therapy applications.

An adenovirus-Epstein-Barr virus hybrid vector that stably transforms cultured cells with high efficiency

EBV episomes are nuclear plasmids that are stably maintained through multiple cell divisions in primate and canine cells (J. L. Yates, N. Warren, and B. Sugden, Nature 313:812-815, 1985). In this report, we describe the construction and characterization of an E1-deleted recombinant adenovirus vector system that delivers an EBV episome to infected cells. This adenovirus-EBV hybrid vector system utilizes Cre-mediated, site-specific recombination to excise an EBV episome from a target recombinant adenovirus genome. We demonstrate that this vector system efficiently delivers the EBV episome and stably transforms a large fraction of infected canine D-17 cells. Using a colony-forming assay, we demonstrate stable transformation of 37% of cells that survive the infection. However, maximal transformation efficiency is achieved at doses of the E1-deleted recombinant adenoviruses that are toxic to the infected cells. Consequently, E1-deleted vector toxicity imposes a limitation on our current vector system.

Adenovirus dodecahedron, a new vector for human gene transfer

Recombinant adenovirus is one of most efficient delivery vehicles for gene therapy. However, the initial enthusiasm for the use of recombinant adenovirus for gene therapy has been tempered by strong immune responses that develop to the virus and virus-infected cells. Even though recombinant adenoviruses are replication-defective, they introduce into the recipient cell, together with the gene of interest, viral genetes that might lead to fortuitous recombination if the recipient is infected by wild-type adenovirus. We propose the use of a dodecahedron made of adenovirus pentons or penton bases as an alternative vector for human gene therapy. The penton is a complex of two oligomeric proteins, a penton base and fiber, involved in the cell attachment, internalization, and liberation of virus into the cytoplasm. The dodecahedron retains many of the advantages of adenovirus for gene transfer such as efficiency of entry, efficient release of DNA from endosomes, and wide range of cell and tissue targets. Because it consists of only one or two adenovirus proteins instead of the 11 contained in an adenovirus virion and it does not contain the viral genome, it is potentially a safer alternative to recombinant adenovirus.

The penton base of human adenovirus type 3 has the RGD motif

The gene encoding the penton base of human adenovirus (Ad) type 3 has been sequenced. The resulting amino-acid sequence has an Arg-Gly-Asp (RGD) motif located near its middle in a hydrophilic region. The same motif is found in serotypes 2, 5 and 12. This sequence was found [Wickham et al., Cell 73 (1993) 309-319] to be involved in the internalisation of Ad2 through an interaction with some specific integrins.

Cell-binding domain of adenovirus serotype 2 fiber

The adenovirus fiber appears as a long, thin projection terminated by a knob (head). The fiber consists of a trimeric protein whose head domain is thought to interact with cell receptors. The head part (amino acids 388 to 582) of adenovirus type 2 fiber was produced in a baculovirus expression system. The purified protein was shown to cross-link into trimers. It was very resistant to proteolytic attack and seemed to attain a high degree of compactness. The head domain efficiently inhibited attachment of adenovirus to receptors on the surface of HeLa cells, thereby confirming the hypothesis that the head domain interacts with viral receptors.

Cutaneous T-cell lymphoma with massive co-infiltration of polyclonal B cells

A 76-year-old man presented with a 3-month history of a cutaneous nodule on the right thigh. The tumour was composed of CD3+, large atypical cells, and CD20+, small normal-appearing cells. Flow cytometry showed that CD20+ cells outnumbered CD3+ cells. By Southern blot hybridization analyses, the malignant cells were shown to be of T-cell origin, because of the presence of rearranged bands for the beta chain of the T-cell receptor, but not for the immunoglobulin heavy chain. This case represents a T-cell lymphoma intermingled with a large number of non-neoplastic B cells.

Sequence conversion during postreplicative adenovirus overlap recombination

Sequence conversion efficiently transfers genetic information in high yield during postreplicative adenovirus overlap recombination. This process is intrinsically nonreciprocal, depends on adenovirus-specific strand-displacement replication by both partner molecules, and requires that complementary sequences on displaced strands must exceed a minimal length to form a heteroduplex intermediate.

Clonal evolution of a follicular lymphoma: evidence for antigen selection

The potential role antigens play in growth stimulation or in clonal selection of follicular lymphomas is unknown. To study this issue, we sequenced the immunoglobulin heavy chain variable region genes expressed by a follicular lymphoma from multiple biopsy specimens and also cloned and sequenced the corresponding germ-line variable gene from this patient. Comparison to the germ-line gene revealed numerous nucleotide substitutions in all of the lymphoma variable gene sequences. Some of the substitutions may have occurred in the nonmalignant precursor B cell that gave rise to this lymphoma because they were shared among all of the variable genes, but many of the mutations accumulated as the malignant clone expanded. The mutations were distributed in such a way that strongly suggested the majority of tumor cells had been positively selected through their antigen receptor. This was especially evident for the mutations that developed late in the clonal evolution of this lymphoma. These findings indicate that antigen stimulation may be involved in the growth of follicular lymphoma tumors.

A pathologic study of childhood lymphoma in Taiwan with special reference to peripheral T-cell lymphoma and the association with Epstein-Barr viral infection

The authors retrospectively reviewed the clinicopathologic and immunologic features of 65 consecutive cases of childhood lymphoma reported between 1980 and 1989. Southern blot hybridization was also performed in 23 cases to study their association with Epstein-Barr virus (EBV) and human T-cell leukemia virus type 1 (HTLV-1). The 65 cases included 56 non-Hodgkin's lymphoma (NHL) (86%) and 9 Hodgkin's disease (HD) (14%). The NHL could be classified into the following groups: Group I, small noncleaved cell lymphoma (20 cases); Group II, lymphoblastic lymphoma (17 cases); Group III, large cell lymphoma (17 cases); and miscellaneous (2 cases). There was no follicular lymphoma case. Immunohistochemical study on paraffin sections and/or frozen specimens in 47 cases of NHL showed that all the Group I cases belonged to B-cell neoplasm (17 of 17 cases); most of the Group II cases belonged to T-cell neoplasm (9 of 14 cases); and most of the Group III cases were peripheral T-cell lymphoma (PTL) (8 of 16 cases), including 2 cases of Ki-1 lymphoma. The majority of childhood NHL belonged to high-grade malignancy with an aggressive clinical course (median survival time, 8 months). The EBV DNA could be detected from the tumor tissues in 4 of 6 PTL, but in none of the remaining 19 cases of NHL including 6 Burkitt's type lymphomas. HTLV-1 proviral genome was not detected in all specimens examined. The authors concluded that the distribution pattern and clinicopathologic feature of childhood lymphoma in Taiwan are comparable to that in Japan and western countries. The frequent association of EBV with aggressive PTL was unique and deserves additional investigation.

Inverted repeats direct repair of adenovirus minichromosome ends

Adenovirus DNA initiates strand-displacement replication from origins located in identical inverted terminal repetitions (ITRs). Panhandle structures, formed by base pairing between ITRs on the displaced strands, have been proposed as replication intermediates for complementary strand synthesis. We have used a model system, which separates adenovirus replication origin sequences from those involved in panhandle formation, to study the length and sequence integrity of panhandles. By making a series of unidirectional deletion in the panhandle sequence, we show that 31 bp are necessary for panhandle formation. Removal of long stretches of 3'-unpaired nucleotides distal to the panhandle is extremely efficient. Our results argue for the formation of panhandles during adenovirus DNA replication and provide a mechanism for maintaining sequence identity between distantly located inverted repetitions. The size constraint may explain why the adenovirus ITRs are larger than the viral DNA replication origins.

Functional and structural effects of an Ala to Val mutation in the adenovirus serotype 2 fibre

H2ts125 is a fibre-defective, temperature-sensitive mutant of adenovirus serotype 2. H2ts125 fibre is unstable at the non-permissive temperature (ts phenotype), and does not migrate in the same way as the wild-type fibre in an SDS/polyacrylamide gel (elm phenotype). Sequence analysis has shown that H2ts125 carries two mutations on the fibre gene: Leu105 to Phe, and Ala434 to Val. Analysis of the structural modifications occurring in H2ts125 fibre was performed using peptide finger-printing and antipeptide sera as immunological probes. We found that all the detectable structural alterations in the mutant fibre were due to the substitution on codon 434. In addition, the ts phenotype was rescued by a wild-type DNA fragment containing the 3' moiety of the fibre gene and overlapping the 434th codon. Morphological analysis of fibre molecules observed under the electron microscope showed minor but statistically significant differences in the fibre length between mutant and wild-type. The mutant fibre was found to be slightly longer (308.8 +/- 1.9 A) than the wild-type fibre (300.1 +/- 2.1 A). Thus both ts and elm phenotypes were carried by the same Ala434 to Val mutation which probably resulted from a change in the three-dimensional structure of the fibre protein, and not from some proteolytic cleavage.

Strands hybridize in postreplicative adenovirus overlap recombination

We describe a postreplicative mechanism for adenovirus overlap recombination. An adenovirus minichromosome system was used to study overlap recombination driven by adenovirus DNA replication. Crossing-over appeared to occur equally at, but not within, the borders of the overlap between partner molecules. We propose that recombination in the minichromosome system proceeds through an intermediate formed by direct hybridization of complementary sequences on displaced strands generated by adenovirus-specific DNA replication. Some, but not all, heterologous regions in the intermediate are susceptible to mismatch correction. This pathway is intrinsically nonreciprocal and differs significantly from other adenovirus recombinational mechanisms that have been described previously.

Linker mutation scanning of the genes encoding the adenovirus type 5 terminal protein precursor and DNA polymerase

The replication of adenovirus DNA requires, in addition to several host factors, three virus-encoded proteins: a DNA binding protein, the precursor of the terminal protein (pTP), and a DNA polymerase (Ad pol). Ad pol and pTP form a tight complex that is necessary for the initiation step in DNA replication. To perform mutation scanning of the adenovirus type 5 pTP and Ad pol a series of in-frame linker insertions of a 12-mer oligonucleotide d(CCCATCGATGGG) were introduced into cloned viral DNA fragments containing coding sequences of these proteins. The insertions are located at recognition sites for several blunt end-cutting restriction endonucleases. Forty different sites were mutagenized and the mutated genes were transferred to a plasmid that contains the left 42% of the adenovirus genome. They were rebuilt into the viral genome by means of in vivo recombination between plasmid DNA and digested adenovirus DNA-TP complex. The resulting viral genomes were tested for viability and rescued virus was analyzed for the presence of the inserted linker oligonucleotide. This procedure resulted in recovery of a number of viable virus mutants with insertions in the pTP or Ad pol genes, all of which are phenotypically silent. The other mutations did not allow virus production. The positions of these apparent lethal codon insertion mutations were useful to identify regions of functional importance in both proteins. It can be concluded that the precursor-specific region of pTP plays an important role in virus multiplication.

Rapid, nonradioactive detection of clonal T-cell receptor gene rearrangements in lymphoid neoplasms

Southern blot hybridization analysis of clonal antigen receptor gene rearrangements has proved to be a valuable adjunct to conventional methods for diagnosing lymphoid neoplasia. However, Southern blot analysis suffers from a number of technical disadvantages, including the time necessary to obtain results, the use of radioactivity, and the susceptibility of the method to various artifacts. We have investigated an alternative approach for assessing the clonality of antigen receptor gene rearrangements in lymphoid tissue biopsy specimens. This approach involves the amplification of rearranged gamma T-cell receptor genes by the polymerase chain reaction and analysis of the polymerase chain reaction products by denaturing gradient gel electrophoresis. By use of this approach, clonal rearrangements from neoplastic lymphocytes constituting as little as 0.1-1% of the total cells in the tissue are detected as discrete bands in the denaturing gel after the gel is stained with ethidium bromide and viewed under ultraviolet light. In contrast, polyclonal rearrangements from reactive lymphocytes appear as a diffuse smear along the length of the gel. Our findings suggest that polymerase chain reaction combined with denaturing gradient gel electrophoresis may offer a rapid, nonradioactive, and sensitive alternative to Southern blot analysis for the diagnostic evaluation of lymphoid tissue biopsy specimens.

Genotypic analysis of T-cell clones derived from cutaneous T-cell lymphoma lesions demonstrates selective growth of tumor-infiltrating lymphocytes

The nature of T cells contained within cutaneous lesions of cutaneous T-cell lymphoma (CTCL) has not been studied at the clonal level. T cells extracted from skin lesions of two CTCL patients were cloned by limiting dilution and propagated in interleukin-2 (IL-2) containing medium with periodic lectin stimulation. Twelve T-cell clones were derived from each patient. In both cases, genotypic analysis of the T-cell clones revealed that these clones had T-cell receptor (TCR) beta- and gamma-chain gene rearrangements distinct from the predominant, presumably malignant, clone present in the skin, lymph nodes, or blood. This suggests that they were derived from presumably reactive (non-malignant) T cells. Furthermore, these clones had gene rearrangements different from each other, indicating their multiple clonal origins. The failure to propagate in vitro the CTCL T-cell clone suggests that CTCL cells may have growth requirements different from normal T cells. Thus, conventional T-cell culturing methods using IL-2 and lectins as mitogen may selectively propagate the presumably reactive T cells contained within the skin lesions. The ability to selectively grow these reactive lesional T cells (so-called tumor infiltrating lymphocytes) raises the possibility that these cells could be used in adoptive immunotherapy.

The proteinase polypeptide of adenovirus serotype 2 virions

The Ad2 proteinase, which is thought to be encoded by a 23-kDa open reading frame located at the end of the L3 family of late mRNAs, is expressed poorly even late after infection. To obtain sufficient proteinase for biochemical characterization, a DNA fragment containing the 23-kDa open reading frame was cloned into plasmids that permit efficient expression in Escherichia coli. Polyclonal antiserum specific for the Ad2 proteinase was produced by immunizing rabbits with a fusion protein that included the entire proteinase open reading frame, and this antiserum was used to show that the product of the 23-kDa reading frame is assembled into virions. Bacterial products corresponding to the complete 204 amino acid proteinase reading frame, to a 9 amino acid proteinase deletion, and to a proteinase fusion protein of 227 amino acids were used to determine the size of the proteinase polypeptide in Ad2 virions and in infected HeLa cell extracts. A single proteinase polypeptide that migrated during SDS-polyacrylamide gel electrophoresis with the 204 amino acid recombinant proteinase was detected in wild-type and H2ts1 virions, and in infected cell extracts. Immunoblot titrations showed that a wild-type Ad2 virus particle contains about 10 proteinase polypeptides; an H2ts1 virion has approximately fivefold less proteinase. In virions, the proteinase was associated primarily with the virus core. The 204 amino acid proteinase produced in E. coli permitted cleavage of the major core protein precursor, P-VII, to mature, authentic VII, but the proteinase deletion lacking 9 amino acids from near the amino-terminus was inactive. These results are inconsistent with autocatalytic processing of the Ad2 proteinase as was reported by Chatterjee and Flint (1987, Proc. Natl. Acad. Sci. USA 84, 714-718).

Physical mapping of two temperature-sensitive adenovirus mutants affected in the DNA polymerase and DNA binding protein

We have determined the exact nature of two thermosensitive (ts) adenovirus mutants, H5ts19 and H5ts149, which map to different genes in the E2 transcription unit. The H5ts19 mutation appears to stem from a single base-pair change of A-T to G-C at position 1840 (numbering as in ref. 1), corresponding to codon 154 of the gene coding for DBP. This results in a glutamine-to-arginine change in the amino-terminal domain of the protein. H5ts19 is defective in a late stage of infection, during virus assembly. This phenotype strongly differs from that described for the limited number of known DBP mutants, indicating that DBP is not only functional during DNA replication, but also plays a role in the late phase of the infection cycle. The defect of the (N group) mutant H5ts149 affects the initiation of viral DNA replication. Marker rescue experiments followed by nucleotide sequence analysis of H5ts149 DNA revealed a single point mutation in the gene coding for the Ad pol. A transition of C-G to A-T at position 7563 (numbering as in ref. 2) changes amino acid residue 411 of Ad pol, a leucine residue, to phenylalanine. This mutation is located in a region conserved among various DNA polymerases, which suggests an important role of this domain in DNA replication.

FseI, a new type II restriction endonuclease that recognizes the octanucleotide sequence 5' GGCCGGCC 3'

A Type II restriction endonuclease, designated FseI, has been partially purified from a Frankia species (NRRL 18528). This enzyme cleaves Adenovirus 2 DNA at three sites, but does not cleave the DNAs from bacteriophages lambda, T7, and phi X174, the animal virus SV40, pUC18 and pBR322. FseI recognizes the octanucleotide sequence 5' GGCCGG decreases CC 3' and cleaves as indicated by the arrow. The frequency of occurrence of FseI sites within sequenced regions of the human genome is similar to that for NotI sites.

T cell receptor beta-chain gene rearrangement without gamma-chain gene rearrangement in cutaneous T cell lymphoma: an unusual finding

T cells from the blood and skin of a patient with cutaneous T cell lymphoma demonstrated rearrangement of the T cell receptor beta-chain gene in the absence of rearrangement of the gamma-chain gene. To our knowledge, this has not been previously reported. This finding was unexpected in light of prevailing concepts of T cell ontogeny. Potential explanations for it are discussed.

Detection of monoclonal B lymphocytes in bone marrow and peripheral blood of multiple myeloma patients by immunoglobulin gene rearrangement studies

To investigate whether B lymphocytes are involved in the malignant cell clone of multiple myeloma (MM), we performed immunoglobulin gene rearrangement analysis of mononuclear cells and separated B lymphocytes, isolated from bone marrow and peripheral blood of MM patients. The B lymphocytes were separated by immunomagnetic beads, coated with an HLA class II specific antibody. Southern blot analysis with a JH probe revealed in the bone marrow of three out of seven patients identical immunoglobulin gene rearrangements in the B lymphocytes when compared to the plasma cells. Out of 10 patients, two patients with a high tumour burden were found to have monoclonal B lymphocytes in the peripheral blood. These results suggest that B lymphocytes in the bone marrow are part of the myeloma clone and that they can circulate in the peripheral blood. Although previous studies indicated that the ratio of K to lambda bearing lymphocytes in the peripheral blood can provide evidence for B cell monoclonality, we did not find a correlation between the results of K/lambda analysis and immunoglobulin gene rearrangement.

Characterization of the adenovirus 2 virion protein, mu

Adenovirus 2 virions contain a small, highly basic protein known as mu (mu). Partial sequence analysis of mu labeled with radioactive amino acids showed that it is derived from an 11-kDa virion precursor protein, L2-79R. Amino acid analysis, direct microsequence analysis, time-of-flight mass spectrometer analysis, and chemical synthesis demonstrated that mu is the unmodified, 19 amino acid peptide obtained from the 79-residue precursor by adenovirus-encoded proteinase-mediated cleavage after glycine31 and glycine50. Mu bound tightly to DNA and was located in the virion core. In vitro, mu could precipitate DNA fragments, suggesting that it may have a role in viral chromosome condensation.

Synthesis of human adenovirus type 2 fiber protein in Escherichia coli cells

We have cloned and expressed in Escherichia coli the gene encoding the trimeric fiber protein of human adenovirus type 2. A gene expression system based on bacteriophage T7 RNA polymerase was used. Optimal gene expression was obtained with 1-h induction, at a temperature of 30 degrees C. The synthesized protein constituted about 1% of total host-cell protein. During induction, the growth of bacteria carrying the plasmid containing the fiber gene, was retarded compared with that of bacteria carrying the plasmid without the fiber gene. This toxic effect of fiber protein on bacterial hosts could be diminished by addition of glucose to the medium and by maintaining the pH above 7, thus improving the yield of recombinant fiber protein. The fiber protein produced in E. coli is stable during the course of induction. It is insoluble in buffers at physiological pH, in various salt solutions, and in the presence of nonionic detergents. It can be solubilized in 1% sodium dodecyl sulfate or in urea solutions above 2 M. There are indications that recombinant fiber trimerizes spontaneously, since after the removal of urea by dialysis at pH 8, recombinant fibers runs similarly to native trimeric fiber, on nondenaturing polyacrylamide gels. This trimer has, however, a less compact structure than native Ad2 fiber, since during gel filtration recombinant protein is excluded before native protein. It is also more sensitive to chymotrypsin digestion than native fiber.

Activation of an excluded immunoglobulin allele in a human B lymphoma cell line

Mature B cells that express surface immunoglobulin (Ig) are usually committed to their original Ig product. It was shown that such a cell can replace its light chain by rearranging and expressing a new light chain from the other allele. Anti-idiotype antibodies were used to isolate idiotypic variants from a surface IgM+lambda+ human B cell tumor line. The variants expressed a new lambda light chain. Both the original and the new lambda transcripts were present in the variant cells, but only the new one was expressed as a protein on the cell surface. Therefore, although the cell exhibited allelic exclusion and had only one Ig receptor at a time, the commitment to a particular light chain gene was reversible.

Detection of clonal T-cell receptor gene rearrangements in the peripheral blood of patients with mycosis fungoides/Sezary syndrome

Involvement of the peripheral blood in mycosis fungoides/Sezary syndrome (MF/SS) has a significant impact upon prognosis, but it is often difficult to distinguish circulating cells of MF/SS from atypical reactive lymphocytes. We compared the standard morphologic method of identifying leukemic cells, the Sezary preparation, to a genotypic method using Southern blot analysis of T-cell receptor gene rearrangements in concurrent blood samples. We studied 26 MF/SS patients, five of them in remission, together with five controls from cases of various non-MF/SS skin diseases. Six of 26 MF/SS patients had morphologically atypical circulating leukocytes (3%, 4%, 5%, 14%, 16%, 19%). Seven of 26 MF/SS patients had clonal T-cell receptor gene rearrangements, including the four patients with the greatest percentages of atypical cells and three patients lacking atypical cells. Six of seven patients had skin disease at the time of sampling, including three with erythroderma, two with generalized thick plaques, and one with generalized patches, while one patient was in clinical remission. All five controls lacked morphologic and genotypic evidence of atypical or clonal T-cells. Relative to genotyping, in our series the Sezary preparation was less sensitive and less specific. There were three apparent false negative results in the Sezary preparations, and two potential false positive (patients with 3% and 4% atypical leukocytes); however, there was agreement between the two techniques in most cases. We conclude that gene rearrangement studies may provide an effective test with which to assess the peripheral blood of MF/SS patients.

Identification of mouse adenovirus type 1 early region 1: DNA sequence and a conserved transactivating function

The left end of the genome of mouse adenovirus type 1 (also known as strain FL) was characterized by determination of the DNA sequence, amino acid similarities with early region proteins of primate adenoviruses, and a functional assay. Several specific DNA sequence features were similar to those found in human adenoviruses, and open reading frames from this region could encode proteins similar to human adenovirus early region 1A and early region 1B proteins. DNAs from this region were tested in transient-expression assays in human and mouse cells were found to transactivate the human adenovirus type 5 early region 3 promoter fused to the chloramphenicol acetyltransferase gene. The data indicate structural and functional homologies between mouse adenovirus type 1 early region 1 and early region 1 of primate adenoviruses.

Epithelium-specific response of cultured keratinocytes to infection with adenovirus type 2

Adenoviruses are pathogenic for certain stratified squamous epithelia. The sites most frequently involved are the upper respiratory tract and oropharynx. Adenovirus infections of the epidermis are quite rare. We examined the virus-cell interactions of adenovirus type 2 (Ad2) and cultured human keratinocytes grown from a variety of body sites. Our intent was to explore the nature of the apparent epithelium-specific susceptibility to Ad2. In brief, we found that in vitro viral susceptibility of the keratinocytes could be reliably predicted based on whether the cells originated from an epidermal or oropharyngeal surface. Ad2 proceeded through a complete vegetative cycle when used to infect cultured keratinocytes from oropharyngeal sites (e.g., gingiva and soft palate). In contrast, Ad2 infection was severely restricted in keratinocytes from epidermal sites (e.g., foreskin, abdomen, and buttock). These results demonstrate that the in vitro response to infection with Ad2 reflects in vivo tissue-specific susceptibility. In vivo, cervical epithelium is rarely infected with Ad2 and yet in culture, cervical keratinocytes were fully permissive for Ad2 replication. We propose that the permissive or nonpermissive response to Ad2 may be regulated by a particular aspect of cell phenotype. Because the permissive responses seen in this study were all generated in keratinocytes from mucosal sites, it is possible the in vitro response to Ad2 reflects inherent differences between mucosal and epidermal keratinocytes.

Characterization of the genome of a vaccine strain of canine adenovirus type 1

Restriction endonuclease cleavage maps have been constructed for the genome of a canine adenovirus type 1 (CAV-1) vaccine strain (CLL; Connaught Laboratories, Ltd., Willowdale, Ontario). Restriction enzyme analyses were also carried out on CAV-1 (CLL) genomes isolated from viral stocks over 8 serial passages in a dog kidney cell line (DK 6722). The right hand 20% of the genome became more heterogeneous in size with increasing passage in DK 6722 cells due to deletions up to 3-4 kb, whereas the left terminal region was stable throughout these passages. A comparative study of CAV-1(CLL) and a virulent strain of CAV-1, Glaxo, revealed that the genome of CAV-1(CLL) was the shorter, by about 480 bp, within the region covering 0.83-0.91 map units. By virtue of its location within the genome and its dispensable nature for viral growth, this region would appear to encompass a genetic sequence corresponding to the E3 region of human adenoviruses. In terms of viral attenuation, the possible importance of the observed differences between CAV-1(CLL) and CAV-1(Glaxo) is discussed.

Interaction of human adenovirus serotype 2 with human lymphoid cells

Human adenoviruses (e.g., Ad2, Ad5) establish chronic infections in human lymphoid-derived cell lines, including Raji and Jijoye (R.E. Wallace, 1969, Proc. Soc. Exp. Biol. Med. 130, 702-710; N. Faucon, G. Ogier, and Y. Chardonnet, 1982, J. Natl. Cancer Inst. 69, 1215-1220); however, the mechanisms by which chronic infections are established and maintained are not understood. When Raji or MOLT-3 cell cultures were infected with Ad2 at high multiplicity, these cell lines continued to grow exponentially and produced only small amounts of infectious virus. Virus-specific antigens, including the DNA-binding protein and hexon, were expressed in only 5% of the Ad2-inoculated cultures. All Raji and MOLT-3 cells were found to have adenovirus receptors, but the Ad2 virions that adsorbed to most Raji cells were sequestered in caps, suggesting that most cells fail to internalize adsorbed Ad2. Cell synchronization experiments showed a correlation between the proportion of cells that became productively infected and the proportion of cells in mitosis at the time of infection. In contrast, primary blood lymphocytes had few, if any, Ad2 receptors and were not productively infected by Ad2.

In vitro analysis of cell populations involved in Hodgkin's disease lesions and in the characteristic T cell immunodeficiency

Hodgkin's disease (HD) is an aggressive human lymphoproliferative disease that displays a curious pleomorphic histopathologic appearance unlike that of any of the common non-Hodgkin's lymphomas (NHL). Although the bizarre giant cells of the HD lesion, the Reed-Sternberg cells (RSC) and mononuclear variant Hodgkin's cells (HC), have been considered to be malignant cells, little objective evidence supports this conclusion. We have studied the proliferative characteristics of T cell as well as RSC and HC-enriched populations from HD lesions, and found the majority of the proliferative activity in the T cell populations. RSC-enriched populations not only showed little spontaneous proliferation, but also did not respond to a variety of cytokine growth factors in vitro, suggesting that these cell populations are not actively growing cells. Further molecular studies to identify possible monoclonal T or B cell populations in HD lesions, using a TCR beta chain probe and IgH probes respectively on Southern blot analysis, revealed no evidence of monoclonal lymphoid cell populations. Additional studies on the characteristic T cell immunodeficiency in HD were also undertaken. Our previous studies had associated a decrement in IL-2 production with this defect. Our studies now show that an intrinsic T cell abnormality exists when HD patients' T cells are stimulated with agonistic MAb that can optimally activate and stimulate IL-2 production in normal control T cells.

Characterization of the spectrum of postthymic T-cell malignancies in Taiwan. A clinicopathologic study of HTLV-1-positive and HTLV-1-negative cases

Postthymic T-cell malignancy shows marked geographic, clinicopathologic, and prognostic diversity. The frequency and spectrum of T-cell malignancies in Taiwan were investigated. Fifty-two patients (35 male and 17 female) with a median age of 49 years, were consecutively encountered between October 1983 and April 1987; these accounted for 39% of non-Hodgkin's lymphoma cases seen in our institutions. Ten patients (19.3%) had adult T-cell leukemia/lymphoma (ATL) associated with human T-cell leukemia virus (HTLV-1). Patients with ATL had disease similar to that reported from southwestern Japan and the Caribbean. They had frequent skin lesions (60%), hypercalcemia (40%), and a rapid clinical course with a median survival of 1.3 years. The 35 HTLV-1-negative peripheral T-cell lymphomas (PTL) were similar to PTL in western countries, manifesting frequent visceral, cutaneous, and vascular tropisms. Marrow involvement was documented at presentation in 39% and Stage III/IV disease in 80% of the PTL patients. The histology of PTL usually expressed prominent reactive features which is distinct from that in ATL. Several subcategories could be defined: Hodgkin's-like PTL in nine patients, T-zone lymphoma in three, angioimmunoblastic lymphadenopathy-like lymphoma in one, Lennert's lymphoma in three, and angioinvasive lymphoma in four. Two HTLV-1-negative PTL had neoplastic cells with clover-shaped nuclei and were designated as ATL-like. Morphologic classification based on the modified Working Formulation showed prognostic correlation, with median survival of less than 6 months for large cell/immunoblastic PTL, compared with 5 years for patients with small/medium cell PTL. Both low- and high-grade PTL seem to represent an incurable disease. Classical cutaneous T-cell lymphoma (seven cases) is relatively unusual in Taiwan, compared with the frequency of PTL. Post-thymic T-cell malignancies in Taiwan include HTLV-1-positive and HTLV-1-negative diseases, both of which have a poor prognosis and resemble similar T-cell malignancies in the East and West.

Single cell origin of bigenotypic and biphenotypic B cell proliferations in human follicular lymphomas

To investigate the possible relatedness of the subpopulations that make up so-called biclonal lymphomas, we examined five bigenotypic and biphenotypic follicular lymphomas using DNA probes specific for the t(14;18) chromosomal translocation, which is a characteristic feature of these neoplasms. On Southern blot analysis, both subpopulations from four of five lymphomas contained comigrating t(14;18) DNA rearrangements, confirming the single cell origins for these neoplasms. No comigrating t(14;18) DNA rearrangements were observed in the fifth lymphoma, but nucleotide sequence analysis of cloned, breakpoint DNA showed identical t(14;18) crossovers in the two subpopulations. The migration differences of both the Ig and chromosome 18 DNA rearrangements were shown to result from somatically acquired mutations of the Ig genes from the fifth lymphoma. These studies indicate that Ig gene rearrangements and idiotope expression are not consistently stable clonal markers since they are subject to variability as a result of somatic mutation. Although translocated chromosome 18 DNA rearrangements are more reliable, they may also vary among cells of some tumors since somatic mutation can affect, as well, DNA of translocated alleles in follicular lymphomas.

Retention of an idiotypic determinant in a human B-cell lymphoma undergoing immunoglobulin variable-region mutation

Tumor cells from a patient with B-cell lymphoma were fused with a mouse myeloma cell line. A set of heterohybridomas was thus derived, each of which represented a separate clonal derivative from the tumor cell population. The immunoglobulins secreted by these cell lines reacted variably with a panel of anti-idiotypic antibodies, indicating that the tumor was heterogeneous; however, one antibody, 4D6, reacted strongly with the product of all the heterohybridomas. cDNA for the immunoglobulin heavy chain variable-region genes expressed in these heterohybridomas was cloned and sequenced. Comparison of these sequences indicated that the cells expressing them were clonally related but that they had undergone considerable mutation. Despite mutation, the cells in this tumor population continued to express a functional immunoglobulin molecule and to retain, over a span of 3 years, the idiotypic determinant defined by the 4D6 monoclonal antibody. Thus a selective force existed within the host to retain tumor cells bearing an immunoglobulin molecule with a particular idiotypic structure.

Multiple reiteration of a 40-bp nucleotide sequence in the inverted terminal repeat of the genome of a canine adenovirus

The DNA of a vaccine strain of canine adenovirus type 1 [ICHV vaccine; Connaught Laboratories, Ltd.; CAV-1(CLL)] has been cloned in plasmid pAT153 in the form of subgenomic BamHI digestion fragments. Analysis of the nucleotide sequences of cloned terminal fragments has revealed an inverted terminal repeat (ITR) with a minimum length of 198 nucleotides, including a tandem reiteration of the 40-bp nucleotide sequence from positions 14 to 53. The ITRs had the 5'-CATCATCAAT ... sequence typical of adenoviruses and the highly conserved sequence ATAATATAC (nucleotides 9-17) of human strains. Additionally, one BamHI A clone (left terminus) contained three sequential copies of the 40-bp sequence, and two BamHI C clones (right terminus) contained at least seven. These did not appear to be artifacts of cloning, since evidence was obtained that the multiple reiterations also occurred in DNA isolated from intact virus. By analogy with human adenoviruses, the repetitive sequence in the CAV-1(CLL) genome encompasses the entire nuclear factor I (NFI) binding site of the origin of DNA replication. Additionally, the 40-bp nucleotide sequence was found to contain the sequence AGG(N)4GCCTAA (nucleotides 27-39), which closely resembles the concensus sequence of the human adenovirus NFI binding site [TGG(N)6-7GCCAA; nucleotides 25-38]. It appears, therefore, that the Connaught CAV-1 vaccine contains reiterated copies of an essential part of the adenoviral origin of DNA replication. A mechanism is proposed for the generation of multiple reiterations of sequences in the right ITR, given an initial single tandem repeat in the left ITR.

The creation of adenovirus genomes with viable, stable, internal redundancies centered about the E2b region

During the course of constructing new adenoviral strains by overlap recombination, we have discovered that internally redundant viable genomes can be created by end-to-end joining of the input DNA molecules. The cellular functions responsible for the end-joining activity frequently ligated the overhanging single strands of the complementary ends to form a novel restriction site at the junction. In 2 of the 17 cases analyzed in detail by restriction digestion, and some sequence determinations, the cellular functions had repaired the ends, presumably prior to end-joining. Four of the isolates had suffered deletions at the junction ranging in size from 13 to 532 bp. The isolate with the largest deletion also had an insertion of 14 bp of unknown origin at the site of the deletion. All of the redundant isolates replicated as efficiently as isogenic unit length strains, and plaque dilution titrations obeyed one-hit kinetics, showing that the redundant genomes were nondefective. Nevertheless unit-length genomes were observed at a low level (some 5 to 10% of the total) in stocks of each isolate before and after plaque purification. They presumably arose by recombination between the redundant sequences either intra- or intermolecularly. Evidence from Southern blot analysis showed that molecules with three copies of the redundant sequences also arose and could be detected both in intracellular and in capsid viral DNA. These species would arise by unequal crossing-over between redundant genomes. The efficient replication of the redundant species demonstrates that the precise spatial relationships between splice donors and acceptors on either strand, in this region of the genome, do not have to be rigidly maintained. These data suggest that it may be possible to place other genetic information between the DNA polymerase and terminal protein precursor genes and have it expressed from the major late promoter in its normal location.

Overproduction of polyomavirus middle T antigen in mammalian cells through the use of an adenovirus vector

To overproduce biologically active polyomavirus middle T antigen, we used an adenovirus vector and human 293 cells as hosts. Two helper-independent recombinant adenoviruses were isolated that contain a hybrid transcription unit, in differing orientations, at a site in the adenovirus genome from which the E1a and most of the E1b transcription units have been deleted. The hybrid transcription unit consists of the adenovirus type 2 major late promoter and tripartite leader and a cDNA segment capable of encoding polyomavirus middle T antigen and accompanying 3' RNA-processing signals. Both recombinant viruses were stable and replicated to high titers in human 293 cells. The polyomavirus sequences were expressed, predominantly at late times after infection of 293 cells, to yield mRNAs that encoded middle T antigen. One of the recombinant viruses also expressed a middle T antigen-related protein in 293 cells. The latter was translated from one of several novel mRNA species that resulted from aberrant splicing and incomplete RNA processing of precursor RNA transcripts. Comparison of the amount of middle T antigen produced in 3T6 cells infected with polyomavirus with that in 293 cells infected with either of the recombinant adenoviruses, under optimal conditions for each system, revealed at least a 10-fold greater yield of the protein on a per-cell basis in the latter system than in the former. The recombinant-virus-encoded middle T antigen was biologically active, as evidenced by its ability to associate with and serve as a substrate for human pp60c-src. The functionality of the middle T antigen was further confirmed by demonstrating that both recombinant viruses efficiently transformed Rat-1 cells. These recombinant viruses will be useful to overproduce middle T antigen and to introduce the polyomavirus oncogene into a wide variety of mammalian cells.

Construction of a helper-free recombinant adenovirus that expresses polyomavirus large T antigen

Adenovirus-polyomavirus recombinant viruses were constructed in vitro by inserting a hybrid transcription unit composed of the adenovirus type 2 major late promoter and the early coding region of polyomavirus into the adenovirus type 5 vector Ad5 delta E1/dl309. The vector lacks the E1a and E1b transcription units and contains a unique restriction endonuclease cleavage site in their place. The polyomavirus genomic insert contained a small deletion which precluded the synthesis of functional small and middle T antigen but allowed for the synthesis of large T antigen. One recombinant virus, Ad5PyR39, which contained the hybrid transcription unit in the opposite transcriptional orientation from the overall direction of late-gene transcription, was studied in detail. Ad5PyR39 replicated efficiently without a helper virus in human 293 cells and expressed hybrid mRNAs of the expected size and composition that were translated to yield large T antigen. The large T antigen synthesized in 293 cells was the same size as that produced in mouse 3T6 cells lytically infected with polyomavirus, and this protein bound efficiently and specifically to the large-T-antigen-binding sites in polyomavirus DNA. Moreover, the large T antigen encoded by the recombinant virus proved capable of catalyzing the replication in mouse 3T6 cells of a plasmid containing the polyomavirus origin for DNA replication. Comparison of the amount of large T antigen produced in 3T6 cells infected with polyomavirus with that in 293 cells infected with Ad5PyR39, under optimal conditions for each system, revealed at least a fivefold greater yield of the protein on a per cell basis in the latter system compared with the former. Ad5PyR39 should prove to be useful to isolate large quantities of functional polyomavirus large T antigen for structural and biochemical studies.

Adenovirus proteins from both E1B reading frames are required for transformation of rodent cells by viral infection and DNA transfection

To determine the requirements for the individual Ad2 E1B proteins during the transformation of rodent cells, viral mutants were constructed with genetic lesions disrupting the coding sequence of either the 175 amino acid residue (175R) or the 495 amino acid residue (495R) E1B proteins. Point mutations generating stop codons very early in the coding sequences were constructed to prevent the expression of amino-terminal protein fragments which might have biological activity. Mutant virus pm1722 contains a point mutation that terminates translation of the 175R protein after three amino acids. It was completely defective for transformation of CREF cells in virion- and DNA-mediated assays. In HeLa cells, pm1722 replicated as well as wild-type virus but produced an extreme cytopathic effect and fragmentation of host-cell DNA. Nonetheless, we provide evidence that the observed transformation defect is not due to the death of transformed cells. The mutant virus dl1520, a double mutant unable to synthesize the 495R protein, was also extremely defective for the transformation of CREF cells in virion- and viral DNA-mediated assays. This result is in contrast to studies with other Ad5 mutants with lesions in the equivalent protein. Possible explanations for this difference are discussed. Replication of dl1520 in HeLa cells was significantly reduced compared to wild-type. Studies with a third mutant virus, pm2022, which contains a stop codon after the second codon of the 495R protein, suggest that very low levels of 495R protein activity are sufficient for a productive infection and significant transforming activity.

Characterization of a low-molecular-weight virus-associated (VA) RNA encoded by simian adenovirus type 7 which functionally can substitute for adenovirus type 5 VA RNAI

Human adenoviruses (Ads), like Ad type 2 (Ad2) and Ad5, encode a low-molecular-weight RNA (designated virus-associated [VA] RNAI) which is required for the efficient translation of viral mRNAs late after infection. We cloned and characterized a VA RNA gene from simian adenovirus type 7 (SA7) which appears to have biological activity analogous to that of Ad2 VA RNAI. Thus, SA7 VA RNA stimulates protein synthesis in a transient expression assay and can also functionally substitute for VA RNAI during lytic growth of human Ad5. The SA7 genome encodes only one VA RNA species, in contrast to human Ad2, which encodes two distinct species. This RNA is transcribed by RNA polymerase III in the rightward direction from a gene located at about coordinate 30 on the viral genome, like its Ad2 counterparts. SA7 VA RNA shows only a limited primary sequence homology with the Ad2 VA RNAs (approximately 55%); the flanking sequences, in fact, are better conserved than the VA RNA gene itself. The predicted secondary structure of SA7 VA RNA is, however, very similar to that of Ad2 VA RNAI, inferring that the double-stranded nature rather than the primary sequence of VA RNA is important for its biological activity.

Cloning and structural analysis of cDNAs for bcl-2 and a hybrid bcl-2/immunoglobulin transcript resulting from the t(14;18) translocation

cDNAs for the bcl-2 mRNA were cloned from a human common acute lymphoblastic leukemia cell line. Nucleotide sequence analyses showed that the 6 kb bcl-2 mRNA potentially encodes a 26 kd protein that is homologous to a predicted Epstein-Barr virus protein. Most t(14;18) translocation breakpoints cluster within a narrow region of a 5.4 kb exon that contains a long 3'-untranslated region of the bcl-2 mRNA. As a result of t(14;18) translocation, hybrid bcl-2/immunoglobulin heavy chain transcripts are produced that consist of the 5' half of the bcl-2 mRNA fused to a "decapitated" immunoglobulin heavy chain mRNA. Nucleotide sequence analyses confirmed that the hybrid transcripts continue to encode a normal bcl-2 protein. Our results suggest that t(14;18) translocations alter expression of the bcl-2 gene both by transcriptional activation and by abnormal posttranscriptional regulation of bcl-2 mRNA.

Immunoglobulin gene rearrangements in Hodgkin's disease

An initial survey of biopsy specimens from 16 cases of Hodgkin's disease revealed clonal immunoglobulin gene rearrangements in one specimen, which contained large numbers of Reed-Sternberg (R-S) cells. As a result of this finding, the configuration of immunoglobulin and T-cell receptor gene DNA was investigated in biopsy tissues from other cases that were histologically and immunophenotypically consistent with Hodgkin's disease and contained numerous R-S cells. In six of seven such specimens (all of the nodular sclerosing subtype), selected solely on the basis of high R-S cell content and sufficient frozen tissue for study, at least one immunoglobulin gene was found to be rearranged in a clonal manner. Additionally, tissue samples obtained at two different time points from the original patient who showed immunoglobulin gene rearrangements revealed identical patterns of rearrangement. In the majority of cases, only a single gene showed rearrangement, and the rearranged bands in Southern blot autoradiograms were usually considerably less intense than the germline bands. No rearrangements of T-cell receptor DNA were detected in any case with a probe for the beta T-cell receptor gene. The results suggest that clonal cell populations possessing uniform immunoglobulin gene rearrangements are present in tissue in some cases of Hodgkin's disease. It is not possible to determine which cells contain these rearranged genes, but the increased incidence of detectable rearrangements in cases with high numbers of R-S cell raises the possibility that immunoglobulin gene rearrangement occurs in these cells.

An SV40 mutant T antigen does not bind the SV40 viral origin

F8dl is an SV40 deletion mutant that lacks over 60% of the coding sequences for large T antigen and yet is able to immortalize early passage rat cells, to transform established cell lines, and to cause tumors in animals. We report here on the further characterization of this mutant and show that (a) transformation by F8dl is protein mediated but does not require the action of the SV40 small t antigen; (b) the F8dl T antigens have, or are associated with, an ATPase activity; (c) the 34-kDa mutant T antigen of F8dl is localized in nuclei and cell membranes of F8dl transformants and binds to double-stranded DNA; (d) the 20-25 kDa forms of the mutant T antigen are cytoplasmic; and (e) the F8dl T antigens do not bind with high affinity to the SV40 origin of viral DNA replication.

Restricted replication of adenovirus type 2 in mouse Balb/3T3 cells

The nature of the infection of mouse B3T3 cells by adenovirus type 2 (Ad2) has been studied in vitro. Following infection with an adsorbed MOI of 225, more than 90 percent of the cells synthesized both early and late virus-specific antigens. In contrast, the yield of progeny virus varied from only 2 X 10(4) to 2 X 10(6) FFU/2 X 10(5) cells. The range in yields was related, in part, to the number of cell generations from the time of the initial subcloning, the yield increasing with passage level. Infectious center analysis suggested that fewer than 0.5 percent of infected cells synthesized progeny virus. Analysis of DNA synthesis in infected multiplying B3T3 cells demonstrated that cellular DNA synthesis began to be shut off at 12 hours p.i., a time when viral DNA synthesis was beginning. The maximum rate of viral DNA synthesis was approximately 12 percent of that in infected human cells. In contrast to infected multiplying cells, infection of quiescent B3T3 cell cultures resulted in the induction of cellular, along with viral, DNA synthesis. Analysis of late gene expression detected synthesis of most viral polypeptides, but revealed greater than 90 percent reductions in the rate of synthesis of polypeptides II, III, IV, and IX, as compared with infected human cells.

Clonal T-cell populations in lymphomatoid papulosis. Evidence of a lymphoproliferative origin for a clinically benign disease

Lymphomatoid papulosis is a chronic, clinically benign skin disorder that, when examined histologically, is seen to include numerous large, atypical lymphoid cells that display antigenic markers of T lymphocytes. To investigate the disparity between the clinical behavior of this disease and its malignant histologic appearance, we analyzed the DNA from skin lesions of six patients for rearrangements of beta and gamma T-cell receptor genes. Lesions from five of these patients showed between one and three clonal rearrangements for at least one T-cell receptor gene. Three separate biopsy specimens from a single patient showed different patterns of rearrangements for the beta gene in each specimen. Our results indicate that lymphomatoid papulosis is a clonal T-cell lymphoproliferative process that may possibly be multiclonal in origin. We conclude that this disease has both biologic and histologic features consistent with a malignant T-cell neoplasm despite its indolent course.

Construction of a helper-free recombinant adenovirus that expresses polyomavirus large T antigen

Adenovirus-polyomavirus recombinant viruses were constructed in vitro by inserting a hybrid transcription unit composed of the adenovirus type 2 major late promoter and the early coding region of polyomavirus into the adenovirus type 5 vector Ad5 delta E1/dl309. The vector lacks the E1a and E1b transcription units and contains a unique restriction endonuclease cleavage site in their place. The polyomavirus genomic insert contained a small deletion which precluded the synthesis of functional small and middle T antigen but allowed for the synthesis of large T antigen. One recombinant virus, Ad5PyR39, which contained the hybrid transcription unit in the opposite transcriptional orientation from the overall direction of late-gene transcription, was studied in detail. Ad5PyR39 replicated efficiently without a helper virus in human 293 cells and expressed hybrid mRNAs of the expected size and composition that were translated to yield large T antigen. The large T antigen synthesized in 293 cells was the same size as that produced in mouse 3T6 cells lytically infected with polyomavirus, and this protein bound efficiently and specifically to the large-T-antigen-binding sites in polyomavirus DNA. Moreover, the large T antigen encoded by the recombinant virus proved capable of catalyzing the replication in mouse 3T6 cells of a plasmid containing the polyomavirus origin for DNA replication. Comparison of the amount of large T antigen produced in 3T6 cells infected with polyomavirus with that in 293 cells infected with Ad5PyR39, under optimal conditions for each system, revealed at least a fivefold greater yield of the protein on a per cell basis in the latter system compared with the former. Ad5PyR39 should prove to be useful to isolate large quantities of functional polyomavirus large T antigen for structural and biochemical studies.

VA RNAs from avian and human adenoviruses: dramatic differences in length, sequence, and gene location

Human adenoviruses encode low-molecular-weight RNAs, so-called VA RNAs, which are transcribed by RNA polymerase III. These RNAs are required for an efficient translation of viral mRNAs late after infection. The genes for the VA RNAs in the genome of CELO virus were mapped and characterized. The results showed a number of surprising differences between CELO virus and human adenovirus type 2 (Ad2). Thus, the CELO virus genome encoded only one VA RNA species, in contrast to human Ad2, which encoded two distinct species. The VA RNA from CELO virus was much shorter than the Ad2 VA RNAs (90 nucleotides compared with 160 nucleotides), and there existed no detectable primary sequence homology between them. The predicted secondary structure of CELO virus VA RNA was, however, similar to that of the Ad2 VA RNAs, implying that the folding rather than the primary sequence was the important feature for biological activity. CELO VA RNA also stimulated translation in a transient expression assay, as did the Ad2 counterparts, albeit with a much lower efficiency. The location of the gene for CELO VA RNA also differed from all previously characterized serotypes, suggesting that the genome organization of avian and human adenoviruses are different. Finally, termination of CELO VA RNA transcription occurred in a TTATT sequence which is unique as a stop signal for RNA polymerase III transcription.

Clustering of extensive somatic mutations in the variable region of an immunoglobulin heavy chain gene from a human B cell lymphoma

Following treatment of a human B cell lymphoma with an anti-idiotype antibody, a subpopulation of tumor cells remained that had lost the tumor-specific heavy chain idiotypic determinant. Nucleotide sequence analyses of eight independent heavy chain variable region isolates showed extensive point mutations, so that no two sequences were identical. Comparison of pretreatment and posttreatment sequences implicated an amino acid in CDR2 as being involved in the idiotypic determinant. Apparently the malignant B cells escaped the therapeutic effects of the anti-idiotype antibody through an ongoing process of somatic mutation in their immunoglobulin genes. Non-random clustering of amino acid replacements in CDR2 suggested that growth of the tumor may have been influenced by endogenous selective forces interacting with the tumor cell-surface immunoglobulin.