Biomedical subjects

J A Johnston

Publications and source records attributed to J A Johnston.

At least 19 recordsLinked to original sources

PubMed1998

Recruitment of SH2-containing protein tyrosine phosphatase SHP-1 to the interleukin 2 receptor; loss of SHP-1 expression in human T-lymphotropic virus type I-transformed T cells.

Interleukin 2 (IL-2) rapidly induces tyrosine phosphorylation of intracellular substrates, including the IL-2 receptor beta chain (IL-2Rbeta), Janus kinase 1 (Jak1), Jak3, signal transducer/activator of transcription proteins, and Shc, but the mechanism underlying dephosphorylation of these proteins is not known. The src homology 2 (SH2) containing tyrosine phosphatase 1 (SHP-1) is recruited by several hematopoietic surface receptors indicating that this phosphatase plays an important role as a regulator of signaling. We have found that IL-2 induces association of SHP-1 with the IL-2 receptor complex, and that once SHP-1 is recruited to the activated receptor it is able to decrease tyrosine phosphorylation of IL-2Rbeta and the associated tyrosine kinases Jak1 and Jak3. This dephosphorylation is specific as expression of a catalytically inactive form of SHP-1, or expression of the related phosphatase SHP-2 did not result in dephosphorylation of the IL-2 receptor components. Furthermore, we have found that SHP-1 expression is greatly decreased or undetectable in a number of IL-2 independent HTLV-I transformed T cell lines that exhibit constitutive Jak/signal transducer/activator of transcription activation. In HTLV-I infected T cells, down-regulation of SHP-1 expression was also found to correlate with the acquisition of IL-2 independence. These observations suggest that SHP-1 normally functions to antagonize the IL-2 signal transduction pathway and that HTLV-I infection and oncogenic transformation can lead to loss of SHP-1 expression resulting in constitutive activation of IL-2 regulated T cell responses.

Cell Transformation, Viral↗

PubMed1997

Amyloid precursor protein heat shock response in lymphoblastoid cell lines bearing presenilin-1 mutations.

The amyloid precursor protein (APP) gene promoter contains a heat shock element. An abnormal APP heat shock response could increase accumulation of A beta, the APP metabolite found in Alzheimer's disease amyloid plaques. Since A beta production is affected by presenilin-1 (PS-1) mutations, we investigated whether basal APP levels or response to heat shock were altered in lymphoblastoid cell lines from 8 PS-1 mutation-bearers and 9 control members of Alzheimer's disease families. Lymphoblastoid cell lines were incubated at 42 degrees C for 35 min and allowed to recover at 37 degrees C for 1, 3, 8, 24 and 48 h. APP mRNA levels, quantified using RNA-RNA solution hybridisation, increased significantly at 1 and 3 h post-heat shock to between 123% and 163% of pre-heat shock (0 h) levels and returned to normal by 8 h. Semi-quantitative Western immunoblotting of cell lysates using the 22C11 antibody detected two major bands, migrating at approximately 145 and approximately 120 kDa. Band optical densities increased significantly at 3 h to approximately 155% of 0 h levels, following the increase in APP mRNA levels and showing a similar reversibility. APP mRNA and protein responses were comparable in the PS-1 mutation-bearing and control cell lines. This study shows that both APP mRNA and protein are induced in lymphoblastoid cell lines following heat shock and that this response is not affected by PS-1 mutations which are pathogenic for Alzheimer's disease.

Alzheimer Disease↗

PubMed1997

Structural and functional basis for JAK3-deficient severe combined immunodeficiency.

Mutations of the Janus family kinase JAK3 have been found to be responsible for autosomal recessive severe combined immunodeficiency (SCID) in humans. We report here the analysis of four new unrelated patients affected by JAK3-deficient SCID. The genetic defects were heterogeneous and included a large intragenic deletion as well as different point mutations, leading to missense substitutions, early stop codons, or splicing defects. We performed a series of studies of the biochemical events induced by cytokines on lymphoblastoid B-cell lines obtained from these patients. Abnormalities in tyrosine phosphorylation of JAK3 in response to interleukin-2 (IL-2) and IL-4 were present in all patients. Accordingly, IL-2-mediated phosphorylation of STAT5 was also absent or barely detectable. On the contrary, in all cases, we could show reduced but clear phosphorylation of STAT6 upon IL-4 stimulation. In one patient carrying a single amino acid change (Glu481Gly) in the JH3 domain of JAK3, we observed partially conserved IL-2 responses resulting in reduced but detectable levels of JAK3 and STAT5 phosphorylation. Interestingly, the patient bearing this mutation developed a substantial number of circulating CD4(+)/CD45RO+ activated T lymphocytes that were functionally impaired. In two cases, patients' cells expressed JAK3 proteins with mutations in the JH2 pseudo-kinase domain. A single cysteine to arginine substitution (Cys759Arg) in this region resulted in high basal levels of constitutive JAK3 tyrosine phosphorylation unresponsive to either downregulation by serum starvation or cytokine-mediated upregulation. The characterization of the genetic defects and biochemical abnormalities in these JAK3-deficient patients will help define the role of JAK3 in the ontogeny of a competent immune system and may lead to a better understanding of the JAK3 functional domains.

B-Lymphocytes↗

PubMed1997

A comparison of sustained-release bupropion and placebo for smoking cessation.

BACKGROUND AND METHODS: Trials of antidepressant medications for smoking cessation have had mixed results. We conducted a double-blind, placebo-controlled trial of a sustained-release form of bupropion for smoking cessation. We excluded smokers with current depression, but not those with a history of major depression. The 615 subjects were randomly assigned to receive placebo or bupropion at a dose of 100, 150, or 300 mg per day for seven weeks. The target quitting date (or "target quit date") was one week after the beginning of treatment. Brief counseling was provided at base line, weekly during treatment, and at 8, 12, 26, and 52 weeks. Self-reported abstinence was confirmed by a carbon monoxide concentration in expired air of 10 ppm or less. RESULTS: At the end of seven weeks of treatment, the rates of smoking cessation as confirmed by carbon monoxide measurements were 19.0 percent in the placebo group, 28.8 percent in the 100-mg group, 38.6 percent in the 150-mg group, and 44.2 percent in the 300-mg group (P<0.001). At one year the respective rates were 12.4 percent, 19.6 percent, 22.9 percent, and 23.1 percent. The rates for the 150-mg group (P=0.02) and the 300-mg group (P=0.01) -- but not the 100-mg group (P=0.09) -- were significantly better than those for the placebo group. Among the subjects who were continuously abstinent through the end of treatment, the mean absolute weight gain was inversely associated with the dose (a gain of 2.9 kg in the placebo group, 2.3 kg in 100-mg and 150-mg groups, and 1.5 kg in the 300-mg group; P= 0.02). No effects of treatment were observed on depression scores as measured serially by the Beck Depression Inventory. Thirty-seven subjects stopped treatment prematurely because of adverse events; the frequency was similar among all groups. CONCLUSIONS: A sustained-release form of bupropion was effective for smoking cessation and was accompanied by reduced weight gain and minimal side effects. Many participants in all groups were smoking at one year.

Adult↗

PubMed1997

Presenilin-1, amyloid precursor protein and amyloid precursor-like protein 2 mRNA levels in human superior frontal cortex during aging.

The presenilin-1 (PS-1) and amyloid precursor protein (APP) genes carry mutations which co-segregate with early-onset familial Alzheimer's disease. The APP and PS-1 gene products may be involved in the aetiology of the more common late onset form of Alzheimer's disease, where increasing age is a major risk factor. To investigate whether age affected mRNA expression of these genes, we quantified PS-1, total APP, APP containing the kunitz-type protease inhibitor (KPI) domain and amyloid precursor-like protein 2 (APLP2) mRNAs in post-mortem superior frontal cortices from 23 control subjects aged 38 to 89 years using solution hybridisation-RNase protection assays. PS-1, total APP, APP KPI and APLP2 mRNA levels were unchanged over this age range. PS-1 was the least abundant mRNA, at approximately 7% of total APP, the most highly expressed mRNA studied (10.8 copies/pg total RNA). The proportion of total APP encoding the KPI domain (approximately 52%) was unaffected by age. APLP2 mRNA was present at approximately 29% of the total APP mRNA level. Significant positive correlations were present between total APP, APP KPI and APLP2 mRNA levels. These results indicate that the increased prevalence of Alzheimer's disease cannot be attributed to alterations in cortical PS-1, APP and APLP2 mRNA levels or APP KPI splicing during aging.

Adult↗

PubMed1997

A novel pathogenic mutation (Leu262Phe) found in the presenilin 1 gene in early-onset Alzheimer's disease.

Several mutations causing early-onset familial Alzheimer's disease (AD) have been detected in the presenilin 1 (PS-1) gene. Pathogenic mutations have also been described in an homologous gene, presenilin 2 (PS-2). In order to screen for mutations in these genes, cDNA samples from early-onset AD cases were analysed, using single strand conformation polymorphism (SSCP) and direct cDNA sequencing. Two missense mutations in the PS-1 gene were detected, a previously unidentified amino acid substitution Leu262Phe and an earlier reported amino acid substitution Glu318Gly. No disease-related mutations were found in the PS-2 gene.

Age of Onset↗

PubMed1997

G protein subunit levels in fibroblasts from familial Alzheimer's disease patients: lower levels of high molecular weight Gs alpha isoform in patients with decreased beta-adrenergic receptor stimulated cAMP formation.

Abnormalities in G protein linked signal transduction pathways have been detected in fibroblasts from individuals with familial and sporadic Alzheimer's disease. The present study used Gs alpha, Gi alpha, Gq alpha and Go alpha G protein subunit antisera, immunoblotting and densitometry to quantify levels of these proteins in control fibroblasts and in fibroblasts from individuals with familial Alzheimer's disease (FAD). The FAD fibroblasts were from individuals with the APPK670N,M671L mutation, different presenilin 1 (PS1) mutations and one fibroblast cell line from an individual with FAD of unknown genetic aetiology. Results revealed a significant reduction in the large Gs alpha subunit in fibroblasts with the PS1 mutations and in the fibroblast cell line of unknown genetic aetiology, when compared to control levels. This decrease was not apparent in the APPK670N,M671L FAD fibroblasts. Immunoreactivity for Go alpha was not detected in any of the fibroblast cell lines. No differences were observed in Gi alpha or Gq alpha levels when comparing any of the control and Alzheimer's disease fibroblast groups. WE conclude that with the exception of decreased levels of the large Gs alpha subunit, gross alterations in the levels of the Gi alpha, Gq alpha and Go alpha are not associated with the G protein-coupled signal transduction disturbances described previously for some of these FAD fibroblasts.

Alzheimer Disease↗

PubMed1997

Decreased beta-adrenoceptor-stimulated adenylyl cyclase activity in lymphocytes from Alzheimer's disease patients.

Previous studies have shown that in Alzheimer's disease post-mortem brain there are disruptions of both beta1-adrenoceptor-G-protein coupling and G-protein stimulation of adenylyl cyclase activity. Decreased beta-adrenoceptor stimulated adenylyl cyclase activity has also been shown in Alzheimer's disease primary skin fibroblasts. In the present study, we determined the regulation of adenylyl cyclase in Alzheimer's disease patients using an easily accessible tissue source, namely peripheral blood lymphocytes. beta-Adrenoceptor- and forskolin-stimulated adenylyl cyclase activities were investigated in lymphocytes from 12 Alzheimer's disease and 12 carefully matched and selected control subjects. No significant differences were found in basal or forskolin-stimulated enzyme activities between Alzheimer's disease and control lymphocytes. In contrast, isoprenaline-stimulated adenylyl cyclase activities were significantly lower in the Alzheimer's disease groups, as compared to controls. These results indicate that there is a widespread disruption of beta-adrenoceptor-G-protein-enzyme coupling in different tissues from Alzheimer's disease patients, and that adenylyl cyclase disturbances previously reported in Alzheimer's disease brain do not occur as a consequence of disease pathology or of terminal illness.

Adenylyl Cyclases↗

PubMed1997

Interleukin-4 signaling in B lymphocytes from patients with X-linked severe combined immunodeficiency.

Interleukin-4 (IL-4) is an important cytokine for B and T lymphocyte function and mediates its effects via a receptor that contains gammac. B cells derived from patients with X-linked severe combined immunodeficiency (X-SCID) are deficient in gammac and provide a useful model in which to dissect the role of this subunit in IL-4-mediated signaling. We found that although IL-4 stimulation of X-SCID B cells did not result in Janus tyrosine kinase-3 (JAK3) phosphorylation, other IL-4 substrates including JAK1 and IRS-1 were phosphorylated. Additionally, we detected signal transducers and activators of transcription 6 (STAT6) tyrosine phosphorylation and DNA binding activity in X-SCID B cells with a wide range of gammac mutations. However, reconstitution of these X-SCID B cells with gammac enhanced IL-4-mediated responses including STAT6 phosphorylation and DNA binding activity and resulted in increased CD23 expression. Thus, gammac is not necessary to trigger IL-4-mediated responses in B cells, but its presence is important for optimal IL-4-signaling. These results suggest that two distinct IL-4 signaling pathways exist.

B-Lymphocytes↗

PubMed1997

Pharmacokinetics of bupropion and its metabolites in cigarette smokers versus nonsmokers.

Bupropion is an antidepressant agent that is also effective as an aid to quit cigarette smoking. A single 150-mg tablet of sustained-release bupropion hydrochloride was administered to two groups of volunteers, cigarette smokers and nonsmokers, who were matched for race, gender, body frame, age, and weight. Pharmacokinetic parameters were calculated for bupropion, and three major metabolites (hydroxybupropion and the aminoalcohol isomers, threohydrobupropion and erythrohydrobupropion, expressed as a composite total). Mean (+/-SD) values of area under the concentration-time curve from time 0 extrapolated to infinity (AUC0-infinity), maximum concentration (Cmax), time to reach Cmax (tmax), and half-life (t1/2) of bupropion in smokers and nonsmokers, respectively, were 1,164 +/- 220 ng.hr/mL and 1,161 +/- 292 ng.hr/mL; 144 +/- 28 ng/mL and 143 +/- 39 ng/mL; 3.00 +/- 0.50 hours and 2.88 +/- 0.49 hours; and 19 +/- 5 hours and 18 +/- 3 hours. No clinically significant differences between smokers and nonsmokers or between male and female volunteers were observed for the pharmacokinetics of bupropion or its metabolites. The absence of pharmacokinetic differences indicates that dosage adjustments are not necessary when bupropion is prescribed to male and female cigarette smokers.

Adolescent↗

PubMed1997

Advances in the understanding of cytokine signal transduction: the role of Jaks and STATs in immunoregulation and the pathogenesis of immunodeficiency.

Cytokines are of great importance in the growth and differentiation of hematopoietic and other cells. Moreover, they are also crucial in immunoregulation and in host defense. Although our understanding of the molecular basis of cytokine action is far from complete, recent advances have substantially improved our knowledge of cytokine-dependent signal transduction. The delineation of the structure of cytokine receptors and the signaling pathways they utilize has provided clues as to how the strikingly specific effects of cytokines are achieved. Additionally, the basis of some of the pleiotropic and redundant effects of cytokines has also become clear. The discovery of the Janus family of protein tyrosine kinases (Jaks) and the STATs (signal transducers and activators of transcription) has also provided key insights into the mechanism by which intracellular signals are transduced. The following paradigm has emerged: cytokines induce dimerization of receptor subunits that are constitutively associated with Jaks. This activates the Jaks, which then phosphorylate the receptors. The phosphorylated receptors are bound by SH2-containing proteins, one class of which is the STATs. Activated STATs, then, translocate to the nucleus to effect gene transcription. Though the Jaks do not explain much in terms of specificity in signaling, the function of the STATs does. The discovery of patients with autosomal recessive severe combined immunodeficiency due to mutations of a particular Jak, Jak3, and the phenotype of knockout mice lacking Jak3 and various STATs demonstrate the specific and critical roles of these molecules in the development and function of the immune system.

Adjuvants, Immunologic↗

PubMed1997

Double-blind comparison of bupropion sustained release and sertraline in depressed outpatients.

BACKGROUND: A sustained-release formulation of bupropion (bupropion SR), developed with an improved pharmacokinetic profile to permit less frequent dosing than the immediate-release form, has not been evaluated in active comparator trials. This randomized, double-blind, parallel-group trial was conducted to compare the efficacy and safety of bupropion SR and sertraline. METHOD: Outpatients with moderate to severe major depressive disorder (DSM-IV) received bupropion SR (100-300 mg/day) or sertraline (50-200 mg/day) for 16 weeks. Psychiatric evaluations, including the Hamilton Rating Scale for Depression (HAM-D), the Hamilton Rating Scale for Anxiety (HAM-A), the Clinical Global Impressions scale for Severity of Illness (CGI-S), and for Improvement (CGI-I) were completed, and adverse events were assessed in the clinic periodically throughout treatment. Patients' orgasm function was also assessed. RESULTS: Mean HAM-D, HAM-A, CGI-I, and CGI-S scores improved over the course of treatment in both the bupropion SR group and the sertraline group; no between-group differences were observed on any of the scales. Orgasm dysfunction was significantly (p < .001) more common in sertraline-treated patients compared with bupropion SR-treated patients. The adverse events of nausea, diarrhea, somnolence, and sweating were also experienced more frequently (p < .05) in sertraline-treated patients. No differences were noted between the two treatments for vital signs and weight. CONCLUSION: This double-blind comparison of bupropion SR and sertraline demonstrates that bupropion and sertraline are similarly effective for the treatment of depression. Both compounds were relatively well tolerated, and orgasm dysfunction, nausea, diarrhea, somnolence, and sweating were reported more frequently in sertraline-treated patients.

1-Naphthylamine↗

PubMed1996

A new quantitative solution hybridisation-RNase protection assay for APP and APLP2 mRNA.

Amyloid precursor protein (APP) and amyloid precursor-like protein 2 (APLP2) are members of a multigene family of proteins implicated in the pathogenesis of Alzheimer's disease. We describe the development of an RNA-RNA solution hybridisation-RNase protection assay to quantify APP mRNA. APP mRNA splice forms containing the Kunitz-type protease inhibitor (KPI) insert, and APLP2 mRNA in total nucleic acid extracts from a range of tissue types. Solution hybridisation-RNase protection assay enables absolute quantification of target mRNA, by conversion of the hybridisation signal to pg mRNA using a standard curve. The assay is sensitive, capable of detecting 1 pg target mRNA, and reproducible, with an inter-assay variability of less than 10% and an intra-assay variability of 3-4%. We quantified APP and APLP2 mRNA in cell lines and post-mortem human brain tissue samples. To test whether we could detect physiological differences in APP mRNA levels, a fibroblast cell line with a paternal chromosome 21 deletion of the region including the APP gene was analysed and found to express half as much APP mRNA as control fibroblasts. In addition, a reversible, approx. 30% increase in APP mRNA levels was detected in human lymphoblastoid cell lines following heat shock, a physical stimulus previously shown to increase APP expression. Regional differences in the expression of APP and APLP2 were seen in human post-mortem cerebral cortex and cerebellum. Levels of APP and APLP2 mRNA were highest in the temporal cortex, slightly lower in frontal and occipital cortices, and lowest in the cerebellum. The highest proportion of KPI-containing APP was seen in the frontal and temporal cortices. The ratio of APP:APLP2 mRNA was 1:0.3 in the cortical tissue and 1:0.8 in the cerebellum. In conclusion, quantitative solution hybridisation-RNase protection assay of total APP. APP KPI and APLP2 mRNA provides a new tool to improve the resolution of studies of potentially subtle alterations in the expression of these genes in both cell culture model systems and Alzheimer's disease post-mortem human brain tissue.

Amyloid beta-Protein Precursor↗

PubMed1996

Quantification of APP and APLP2 mRNA in APOE genotyped Alzheimer's disease brains.

Amyloid precursor protein (APP) is metabolised to produce A beta, a peptide found aggregated in Alzheimer's disease neuritic plaques. APP is a member of a multigene protein family which includes amyloid precursor-like protein 2 (APLP2). Since A beta accumulation can be triggered by factors acting up- or downstream of APP processing, we investigated whether APP mRNA expression was altered in Alzheimer's disease post-mortem cerebral cortex. In addition, we characterised cortical APLP2 mRNA levels. Quantitative RNA-RNA solution hybridisation-RNase protection was used to assay total APP. APP containing the Kunitz-type protease inhibitor (KPI) insert and APLP2 mRNA in mid-temporal and superior frontal cortices from apolipoprotein E-genotyped subjects with Alzheimer's disease, other neurological diseases and non-demented controls. Approximately 3 times more APP than APLP2 mRNA was detected and about 70% of total APP mRNA contained the KPI insert in the control subjects. Total APP and APLP2 mRNA levels were significantly reduced in Alzheimer's disease mid-temporal, but not superior frontal cortex, suggesting that regional reductions in these mRNA correlate with severity of disease pathology. A small significant increase in the proportion of APP KPI mRNA was seen in both cortical regions in Alzheimer's disease. Apolipoprotein E genotype did not influence cortical levels of total APP, APP KPI or APLP2 mRNA. Alzheimer's disease-related increases in tissue DNA content were seen in both regions studied, while tissue RNA levels were reduced in the positive disease controls. In summary, these results indicate that Alzheimer's disease is not associated with over-expression of either APP or APLP2 mRNA. Our findings reveal a disease-associated increase in the proportion of APP KPI-containing isoforms, and further investigation should clarify whether this predisposes affected individuals to A beta production and aggregation, or reflects later events such as gliosis and neuronal cell death.

Aged↗

PubMed1996

Quantification of presenilin-1 mRNA in Alzheimer's disease brains.

The presenilin-1 (PS-1) gene on chromosome 14 carries mutations which cosegregate with early-onset familial Alzheimer's disease. We quantified PS-1 mRNA in post-mortem mid-temporal and superior frontal cortices from 14 Alzheimer's disease subjects, 9 non-demented controls and 5 subjects with other neurological diseases using solution hybridisation-RNase protection assay. APP and APLP2 mRNAs had previously been quantified in these samples (Johnston et al. (1996) Mol. Brain Res., in press) and subjects were apolipoprotein E (APOE) genotyped. There were no significant differences between PS-1 mRNA levels per pg total RNA in mid-temporal or superior frontal cortices of the Alzheimer's disease subjects, compared to controls. PS-1 mRNA levels corresponded to 10% of total APP and 30% of APLP2 mRNA levels, and were not significantly affected by age, post-mortem delay, tissue pH, or APOE genotype. PS-1 mRNA showed significant positive correlations with APP and APLP2 mRNA levels in mid-temporal cortex and with APP mRNA in superior frontal cortex. This may reflect a co-regulation of the expression of these genes, or the fact that they are expressed in similar neuronal populations.

Age Factors↗

PubMed1996

Genomic sequence, organization, and chromosomal localization of human JAK3.

Members of the Janus (JAK) protein tyrosine kinase family including JAK3 have recently emerged as important components in cytokine signal transduction. Mutations of JAK3 have been found in a number of patients who present with severe combined immunodeficiency. To facilitate the further identification of JAK3-SCID patients and to understand the structure of JAK3 better, we undertook the determination of the genomic sequence, organization, and chromosomal localization of the JAK3 gene. The JAK3 gene was found to consist of 19 exons and 18 introns. Interestingly, the organization of the kinase-(JH1) and pseudokinase-(JH2) domains were found to be dissimilar. In addition, the JAK3 gene was localized to human chromosome 19p13.1. These data should facilitate the identification of patients with this new form of immunodeficiency and will provide insight into the structure of this kinase.

Chromosome Mapping↗

PubMed1996

In vitro correction of JAK3-deficient severe combined immunodeficiency by retroviral-mediated gene transduction.

Mutations affecting the expression of the Janus family kinase JAK3 were recently shown to be responsible for autosomal recessive severe combined immunodeficiency (SCID). JAK3-deficient patients present with a clinical phenotype virtually indistinguishable from boys affected by X-linked SCID, a disease caused by genetic defects of the common gamma chain (gamma c) that is a shared component of the receptors for IL-2, IL-4, IL-7, IL-9, and IL-15. The specific interaction of JAK3 and gamma c represents the biochemical basis for the similarities between these two immunodeficiencies. Both forms of SCID are characterized by recurrent, severe infections leading to death in infancy unless successfully treated by allogeneic bone marrow transplantation. Because of the potentially lethal complications associated with allogeneic bone marrow transplantation and the frequent lack of suitable marrow donors, the development of alternative forms of therapy is highly desirable. To this end, we investigated a retroviral-mediated gene correction approach for JAK3-deficiency. A vector carrying a copy of JAK3 cDNA was constructed and used to transduce B cell lines derived from patients with JAK3-deficient SCID. We demonstrate restoration of JAK3 expression and phosphorylation upon IL-2 and IL-4 stimulation. Furthermore, patients' cells transduced with JAK3 acquired the ability to proliferate normally in response to IL-2. These data indicate that the biological defects of JAK3-deficient cells can be efficiently corrected in vitro by retroviral-mediated gene transfer, thus providing the basis for future investigation of gene therapy as treatment for JAK3-deficient SCID.

B-Lymphocytes↗

PubMed1996

Retroviral-mediated gene correction for X-linked severe combined immunodeficiency.

X-linked severe combined immunodeficiency (XSCID) is a lethal disease caused by a defect in the gene encoding the common gamma chain (gamma-c) of the receptor for interleukin-2 (IL-2), IL-4, IL-7, IL-9, and IL-15. Allogeneic bone marrow transplantation, the current therapy of choice for this defect, is often complicated by graft-versus-host disease and/or incomplete reconstitution of B-lymphocyte functions. Correction of the gene defect at the level of the autologous lymphohematopoietic progenitors could therefore represent an improvement in the medical management of these patients. To study the feasibility of a gene therapy approach for XSCID, a retroviral vector expressing gamma-c was used to transduce Epstein-Barr virus-transformed B-cell lines derived from patients with XSCID. After transduction, XSCID cells newly expressed gamma-c on the cell surface at levels comparable to those observed on B-cell lines obtained from normal donors. Moreover, the reconstituted gamma-c restored function to the IL-2 and IL-4 receptors as shown by signal transduction mediated by phosphorylation of the JAK1 and JAK3 members of the Janus family of tyrosine kinases and by restoration of cellular proliferation in response to IL-2.

B-Lymphocytes↗