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J A Thompson

Publications and source records attributed to J A Thompson.

At least 199 records · Page 11Linked to original sources
PubMed1991

Carcinoembryonic antigen gene family: molecular biology and clinical perspectives.

The carcinoembryonic antigen (CEA) gene family belongs to the immunoglobulin super-gene family and can be divided into two main subgroups based on sequence comparisons. In humans it is clustered on the long arm of chromosome 19 and consists of approximately 20 genes. The CEA subgroup genes code for CEA and its classical crossreacting antigens, which are mainly membrane-bound, whereas the other subgroup genes encode the pregnancy-specific glycoproteins (PSG), which are secreted. Splice variants of individual genes and differential post-translational modifications of the resulting proteins, e.g., by glycosylation, indicate a high complexity in the number of putative CEA-related molecules. So far, only a limited number of CEA-related antigens in humans have been unequivocally assigned to a specific gene. Rodent CEA-related genes reveal a high sequence divergence and, in part, a completely different domain organization than the human CEA gene family, making it difficult to determine individual gene counterparts. However, rodent CEA-related genes can be assigned to human subgroups based on similarity of expression patterns, which is characteristic for the subgroups. Various functions have been determined for members of the CEA subgroup in vitro, including cell adhesion, bacterial binding, an accessory role for collagen binding or ecto-ATPases activity. Based on all that is known so far on its biology, the clinical outlook for the CEA family has been reassessed.

Amino Acid Sequence↗
PubMed1991

An improved microcomputer program for finding gene- or gene family-specific oligonucleotides suitable as primers for polymerase chain reactions or as probes.

We present here an easy-to-use computer program which finds oligonucleotides suitable as primers in polymerase chain reactions (PCR) or as probes for hybridization. In contrast to other programs used for this purpose, the additional advantage of this one is the possibility of directly detecting gene- as well as gene family-specific oligonucleotides. For this purpose, up to 200 different DNA sequences, of maximally 65,000 nucleotides each, can be scanned in a single search to ensure either single or multiple gene binding of the PCR primers or probes. Specific oligonucleotides for genes carrying internal repetitions and for single genes belonging to a set of highly conserved genes can also be detected. Many parameters such as exclusion of simple sequences, which are known to be highly repeated throughout various genomes or regions of stable secondary structures in both primer-primer and primer-template, can be taken into consideration and avoided. Furthermore, the G + C content and the length of the oligonucleotides can be changed in a broad range by the user.

Animals↗
PubMed1990

Cloning of a carcinoembryonic antigen gene family member expressed in leukocytes of chronic myeloid leukemia patients and bone marrow.

The carcinoembryonic antigen (CEA) gene family belongs to the immunoglobulin superfamily and can be subdivided into the CEA and pregnancy-specific glycoprotein subgroups. The basic structure of the encoded proteins consists of, in addition to a leader, one IgV-like and 2, 3, or 6 IgC-like domains. These domains are followed by varying COOH-terminal regions responsible for secretion, transmembrane anchoring, or insertion into the membrane by a glycosyl phosphatidylinositol tail. Here we report on the characterization of CGM6, a new member of the CEA gene subgroup, by complementary DNA cloning. The deduced coding region comprises 349 amino acids and consists of a leader, one IgV-like, two IgC-like domains, and a hydrophobic region, which is replaced by a glycosyl phosphatidylinositol moiety in the mature protein. CGM6 transcripts were only found thus far in leukocytes of chronic myeloid leukemia patients, in normal bone marrow, and in marginal amounts in normal granulocytes. The CGM6 gene product might, therefore, represent a myeloid marker. Analyses of CGM6 protein-expressing HeLa transfectants with monoclonal antibodies strongly indicate that the CGM6 gene codes for the CEA family member NCA-95.

Antigens, Neoplasm↗
PubMed1990

Identification and characterization of an adenovirus 2 major late promoter CAP sequence DNA-binding protein.

DNase I footprint analysis of the core adenovirus 2 (Ad2) major late promoter (MLP) has revealed distinct patterns of protection corresponding to the assembly of transcription components during transcriptional initiation (VanDyke, M. W., Sawadogo, M., and Roeder, R. G. (1989) Mol. Cell Biol. 7, 3371-3379). By using partially purified transcription factors, DNase I protection over the TATA box element and the CAP sequence was attributed to the binding of a single factor, TFIID. We have determined, however, that protection of the CAP region results from the binding of a novel factor, designated CAP-site binding factor (CBF), which is chromatographically and functionally distinct from TFIID. DNase I footprint analysis and gel electrophoresis mobility shift competition assays confirm that distinct polypeptides bind to the Ad2 MLP upstream promoter sequence, TATA box, and CAP sequences. When the CAP sequence is mutated, transcriptional activity of the Ad2 MLP is reduced both in vitro and in vivo. The decrease in transcriptional activity correlates with decreased CBF binding activity. Nuclear extracts depleted of CBF also exhibit reduced Ad2 MLP transcriptional activity. The addition of DNA affinity purified CBF, free of TFIID or major late transcription factor, restores the activity to control levels.

Adenoviruses, Human↗
PubMed1990

cDNA and gene analyses imply a novel structure for a rat carcinoembryonic antigen-related protein.

The gene encoding the human tumor marker carcinoembryonic antigen (CEA) belongs to a gene family which can be subdivided into the CEA and the pregnancy-specific glycoprotein subgroups. The corresponding proteins are members of the immunoglobulin superfamily, characterized through the presence of one IgV-like domain and a varying number of IgC-like domains. Since the function of the CEA family is not well understood, we decided to establish an animal model in the rat to study its tissue-specific and developmental stage-dependent expression. To this end, we have screened an 18-day rat placenta cDNA library with a recently isolated fragment of a rat CEA-related gene. Two overlapping clones containing the complete coding region for a putative 709 amino acid protein (rnCGM1; Mr = 78,310) have been characterized. In contrast to all members of the human CEA family, this rat CEA-related protein consists of five IgV-like domains and only one IgC-like domain. This novel structure, which has been confirmed at the genomic level might have important functional implications. Due to the rapid evolutionary divergence of the rat and human CEA gene families it is not possible to assign rnCGM1 to its human counterpart. However, the predominant expression of the rnCGM1 gene in the placenta suggests that it could be analogous to one of the human pregnancy-specific glycoprotein genes.

Amino Acid Sequence↗
PubMed1990

Expression of complementary DNA and genomic clones for carcinoembryonic antigen and nonspecific cross-reacting antigen in Chinese hamster ovary and mouse fibroblast cells and characterization of the membrane-expressed products.

Complementary DNA clones coding for both carcinoembryonic antigen (CEA), a well characterized colonic tumor marker, and nonspecific cross-reacting antigen (NCA), a related antigen, were expressed in Chinese hamster ovary (CHO) cells and L-cells (mouse fibroblasts). A genomic clone coding for CEA was also expressed in CHO cells. Positive clones were identified by fluorescence flow cytometry and enzyme-linked immunosorbent assay. Membrane location of the recombinant CEA and NCA was confirmed by indirect immunofluorescence labeling of the transfectants, followed by visualization under a fluorescence microscope. The apparent molecular weight of the expressed CEA and NCA were 180,000 and 96,000, respectively, for both cell lines, as determined by immunoblot analysis. The CEA and NCA expressed on CHO cells were sensitive to treatment with phosphatidylinositol-specific phospholipase C (PI-PLC), whereas the CEA and NCA proteins on L-cells were resistant to removal by PI-PLC. Unlike NCA, which contains three methionine residues, the only methionine in CEA is in the C-terminal hydrophobic domain. This domain in CEA was shown to be removed and replaced by a phosphatidylinositol glycan (PI-G) anchor (Hefta et al., Proc. Natl. Acad. Sci. USA, 85: 4648-4652, 1988). The recombinant CEA from both CHO cells and L-cells could be labeled with [3H]-ethanolamine (a component of the PI-G anchor) but not with [35S] methionine, whereas the recombinant NCA could be labeled with both [3H]ethanolamine and [35S]methionine. The labeling studies and PI-PLC treatment results are consistent with the CEA and NCA expressed on CHO cells possessing a PI-G anchor. The CEA expressed on the L-cell transfectants may contain a PI-G anchor which is resistant to cleavage by PI-PLC. In addition, the membrane-bound and secreted levels of CEA from the CHO and L-cell transfectants were determined.

Animals↗
PubMed1990

Enhancement by interleukin 4 of interleukin 2- or antibody-induced proliferation of lymphocytes from interleukin 2-treated cancer patients.

Systemic interleukin 2 (IL-2) and IL-2-activated lymphocytes have induced tumor regression in some cancer patients. The IL-2-activated cells have usually been generated by obtaining peripheral blood mononuclear cells (PBMC) from cancer patients shortly after systemic IL-2 therapy and culturing them with IL-2 in vitro. In an effort to augment the ex vivo generation of such cells preactivated in vivo, we examined the proliferative responses of PBMC from IL-2-treated cancer patients to several proliferative signals including IL-2, interleukin 4 (IL-4), and mitogenic antibodies to CD3 and CD28. Although much is known about the response of normal PBMC to these signals, the possibility was considered that the response of lymphocytes preactivated by IL-2 in vivo might differ from that of normal PBMC. Accordingly, PBMC obtained from ten normal, healthy controls and from 17 patients with advanced cancer 1 to 3 days after systemic IL-2 therapy were cultured for 4 days with IL-4 (1000 units/ml) and/or IL-2 (10 units/ml or 1000 units/ml) or with combinations of IL-4 and anti-CD3 +/- anti-CD28, and they were then tested for proliferation by [3H]thymidine incorporation. IL-4 failed to induce proliferation of normal PBMC and inhibited IL-2-induced proliferation, whereas IL-4 alone induced proliferation in PBMC from five of 11 IL-2-treated patients and did not inhibit but augmented the proliferation induced by IL-2 (10 units/ml and 1000 units/ml) in PBMC from six of nine patients and five of 11 patients, respectively. Anti-CD3 induced proliferation in PBMC from eight of nine patients, and the proliferation was consistently augmented by coculture with anti-CD28. Finally, IL-4 significantly augmented the proliferative responses of PBMC from IL-2-treated patients to anti-CD3, as well as to the combination of anti-CD3 and anti-CD28. Thus, in PBMC from IL-2-treated cancer patients, IL-4 enhanced the in vitro proliferation induced by IL-2 or by anti-CD3 +/- anti-CD28. The results suggest that IL-4 and/or mitogenic antibodies may be useful in augmenting the ex vivo generation of lymphocytes for clinical adoptive immunotherapy.

Adult↗
PubMed1990

Chronic encephalitis, epilepsy, and cerebrovascular immune complex deposits.

Refractory epilepsy, electroencephalographic abnormalities, progressive hemiplegia, and contralateral hemicerebral atrophy developed in a previously healthy 3-year, 9-month-old girl. Extensive laboratory testing showed elevated serum antinuclear antibody titers, cerebrospinal fluid oligoclonal bands, and elevated immunoglobulin G (IgG): albumin ratio, IgG index, and IgG synthesis rate. Pathological study of a subtotal hemispherectomy specimen revealed widespread cerebral vasculitis with immunofluorescence staining for IgG, IgM, IgA, C3, and Clq, and ultrastructural evidence of vascular injury in addition to severe cortical atrophy with marked neuronal loss. Cerebrospinal fluid abnormalities in other reported patients suggest that immunological abnormalities may not be unique to this girl. These data suggest possible immunopathogenetic mechanisms in these patients.

Antibodies, Antinuclear↗
PubMed1990

Comparison of atrial contribution to cardiac hemodynamics in patients with normal and severely compromised cardiac function.

The importance of atrial contribution to cardiac function in patients with congestive heart failure is controversial. Ten patients with severe congestive failure (Group A) and 10 patients with normal ventricular function (Group B) were studied during atrial and ventricular pacing. Left ventricular ejection fraction, baseline pulmonary capillary wedge pressure, and baseline cardiac index were different between Group A and Group B patients: 22 +/- 10 vs. 65 +/- 11 (p less than 0.01); 21 +/- 5 vs. 8 +/- 4, (p less than 0.01); and 2.8 +/- 0.5 vs. 3.5 +/- 1.0 (p = 0.05). Compared with atrial pacing, cardiac index decreased from 2.8 +/- 0.6 to 2.2 +/- 0.5 (p less than 0.01) in Group A and from 3.6 +/- 0.7 to 2.9 +/- 0.5 (p less than 0.01) in Group B, during ventricular pacing. Pulmonary capillary wedge pressure increased by similar amounts in both groups during ventricular pacing. The change in cardiac index, % change in cardiac index, and change in pulmonary capillary wedge pressure from atrial to ventricular pacing, were not different between Group A and Group B patients. By logistic regression analysis, no association was found between the % change in cardiac index and the following variables: left ventricular ejection fraction, left ventricular end-diastolic volume, baseline pulmonary capillary wedge pressure, change in pulmonary capillary wedge pressure, and baseline cardiac index. The atrial contribution to resting steady-state cardiac function is similar between patients with severe congestive failure and those with preserved ventricular function.

Atrial Function↗
PubMed1990

Genomic organization of mouse Fc gamma receptor genes.

We have isolated and characterized the gene coding for the mouse Fc receptor that is termed Fc gamma RIIa. The gene contains five exons and spans approximately 9 kilobases. Unlike most members of the immunoglobulin gene superfamily, this gene utilizes multiple exons to encode its leader peptide. The first exon encodes the hydrophobic region of the signal sequence; the second exon, which contains only 21 base pairs, encodes a segment of the signal peptidase recognition site; and the beginning of the third exon encodes the predicted site of peptidase cleavage. The third and fourth exons each code for immunoglobulin-like extracellular domains. The fifth exon encodes the hydrophobic transmembrane domain and the cytoplasmic tail. Partial characterization of the Fc gamma RIIb gene indicates that it also contains multiple leader exons, including a 21-base-pair exon and two exons coding for homologous immunoglobulin-like extracellular domains. However, the Fc gamma RIIb gene uses four exons to encode its intracytoplasmic region. Analysis using contour-clamped homogeneous electric field (CHEF) gels indicates that the Fc gamma RIIa and Fc gamma RIIb genes are linked within 160 kilobases on mouse chromosome 1.

Amino Acid Sequence↗
PubMed1990

Management and long-term followup of outpatient care in the cardiac transplant recipient.

Successful long-term management of the cardiac transplant patient requires the concerted effort of the patient, the cardiac transplant team, and the primary care physician. The long-term management of these patients will continue to evolve as new immunosuppressive agents are used and new methods of surveillance for rejection are found. The long-term management is indeed one of the most exciting parts of the care of the transplant patient, especially when all those involved can watch the patient enter into a normal lifestyle.

Aftercare↗
PubMed1990

Accelerated coronary atherosclerosis in cardiac transplantation.

The implications of this new aggressive form of coronary disease for the transplant population are obvious. It appears that for the majority of transplant patients we have simply bought some time. We have given them a temporary respite from congestive failure and cardiomyopathy while they surmount the daily challenges imposed by immunosuppression. Clearly, this issue now looms as a major stumbling block toward improving long-term survival. It is no longer enough to simply perform the procedure and submit the patient to the rigors of transplantation, only to obtain 50 percent 5-year survival. We must pay particular attention to the patient postoperatively and make those modifications necessary to improve the individual's risk profile. Moreover, we must continue to concentrate our research efforts on interventions in accelerated coronary disease.

Coronary Disease↗
PubMed1989

Induction of lymphokine-activated killer activity by interleukin 4 in human lymphocytes preactivated by interleukin 2 in vivo or in vitro.

In an attempt to augment the generation of human cytotoxic effector cells for potential cancer therapy with interleukin 2 (IL2) and lymphokine-activated killer (LAK) cells, the effect of interleukin 4 (IL4) on LAK cell induction was studied. In normal human peripheral blood lymphocytes (PBL), IL4 does not induce LAK activity and inhibits LAK induction by IL2. However, since lymphocyte activation, such as with antigen or mitogen, can render them responsive to IL4, the ability of IL4 to induce LAK activity in lymphocytes preactivated in vivo or in vitro with IL2 was investigated. PBL obtained from 12 patients with advanced cancer 1 to 3 days after IL2 therapy and from eight healthy control subjects were cultured 4 to 5 days with or without IL4 and/or IL2 and then tested for LAK activity as assessed by lysis of Daudi in a 4-h 51Cr release assay. In normal PBL, IL4 failed to induce LAK activity and consistently inhibited LAK induction by a suboptimal concentration of IL2 (10 units/ml). By contrast, IL4 induced LAK activity in PBL from seven of twelve IL2-treated patients and augmented LAK induction by the suboptimal IL2 in PBL from five of twelve IL2-treated patients. With an optimal LAK-inducing concentration of IL2 (1000 units/ml), IL4 less consistently inhibited LAK induction in normal PBL and had a variable effect upon LAK induction in PBL from IL2-treated patients. IL4 induced LAK activity in PBL obtained from a cancer patient after, but not before, systemic IL2 therapy. Similarly, IL4 induced LAK activity in normal PBL only after they had been preincubated with IL2. Thus, IL4 induces LAK activity in lymphocytes preactivated by IL2 in vivo or in vitro. Fluorescence-activated cell sorting revealed that the LAK activity, whether induced by IL4 or by IL2, was mediated largely by non-T (CD5-) natural killer-like (CD56+) cells. The results suggest a regulatory relationship between IL2 and IL4 in the induction and/or maintenance of LAK activity, which might be exploited to augment the generation of cytotoxic cells for lymphokine-mediated immunotherapy of human cancer.

Antigens, CD↗