Ethical and practical considerations for cell and gene therapy toward an HIV cure: findings from a qualitative in-depth interview study in the United States

BACKGROUND

HIV cure research involving cell and gene therapy has intensified in recent years. There is a growing need to identify ethical standards and safeguards to ensure cell and gene therapy (CGT) HIV cure research remains valued and acceptable to as many stakeholders as possible as it advances on a global scale.

METHODS

To elicit preliminary ethical and practical considerations to guide CGT HIV cure research, we implemented a qualitative, in-depth interview study with three key stakeholder groups in the United States: (1) biomedical HIV cure researchers, (2) bioethicists, and (3) community stakeholders. Interviews permitted evaluation of informants' perspectives on how CGT HIV cure research should ethically occur, and were transcribed verbatim. We applied conventional content analysis focused on inductive reasoning to analyze the rich qualitative data and derive key ethical and practical considerations related to CGT towards an HIV cure.

RESULTS

We interviewed 13 biomedical researchers, 5 community members, and 1 bioethicist. Informants generated considerations related to: perceived benefits of CGT towards an HIV cure, perceived risks, considerations necessary to ensure an acceptable benefit/risk balance, CGT strategies considered unacceptable, additional ethical considerations, and considerations for first-in-human CGT HIV cure trials. Informants also proposed important safeguards to developing CGT approaches towards an HIV cure, such as the importance of mitigating off-target effects, mitigating risks associated with long-term duration of CGT interventions, and mitigating risks of immune overreactions.

CONCLUSION

Our study identified preliminary considerations for CGT-based HIV cure across three key stakeholder groups. Respondents identified an ideal cure strategy as one which would durably control HIV infection, protect the individual from re-acquisition, and eliminate transmission to others. Known and unknown risks should be anticipated and perceived as learning opportunities to preserve and honor the altruism of participants. Preclinical studies should support these considerations and be transparently reviewed by regulatory experts and peers prior to first-in-human studies. To protect the public trust in CGT HIV cure research, ethical and practical considerations should be periodically revisited and updated as the science continues to evolve. Additional ethics studies are required to expand stakeholder participation to include traditionally marginalized groups and clinical care providers.

Strength limits in mesoscaled 3Y-TZP ceramics for micro-surgical instruments

Micro-surgical instruments are a new application for mesoscale ceramics formed using the lost mold-rapid infiltration forming (LM-RIF) process. Instrument strength and reliability are the foremost concerns for this sensitive application. It is hypothesized that increasing grain size can improve the damage tolerance of the parts associated with the transformation toughening in the 3Y-TZP material, while retaining high strength. In this work, mesoscale bend bars (314 × 22 × 18 µm) of 3Y-TZP fabricated using the LM-RIF process were heat treated at 1400 °C for 1 h, 8 h, or 16 h, respectively, to obtain samples with different grain sizes. Strength tests were performed under three-point bending and results were evaluated using Weibull statistics. Fractographic and confocal Raman spectroscopic analyses were carried out to interpret the data. Experimental findings showed that the characteristic strength decreased with increasing grain size contrary to the damage tolerance hypothesis. An Orowan-Petch model was recalled to correlate the strength with the flaw size to grain size ratio. At fine grain sizes the strength was controlled by the flaws introduced by the LM-RIF process, whereas at large grain sizes the strength become more grain size controlled. Although larger-grained samples did have a higher propensity to transform, and thus increase toughening, exaggerated grain growth in some of the specimens tested caused an additional flaw population which led to an overall lower strength. Finally, based on the experimental observations and fracture mechanics considerations, we believe that an upper bound of ∼2.5 GPa exists for the strength of mesoscale as-fabricated 3Y-TZP ceramic parts.

Temozolomide: Expanding its role in brain cancer

Management of central nervous system (CNS) malignancies continues to be a therapeutic challenge. Both primary and secondary (metastatic) CNS tumors are frequently resistant to commonly used chemotherapeutic agents. Surgery and radiotherapy provide palliation of symptoms but usually do not lead to curative outcomes. Alkylating agents have been used in the therapy of primary brain cancer for several decades. This group of medications has the ability to penetrate blood-brain barrier, achieving cytotoxic concentrations in cerebrospinal fluid and brain parenchyma. Temozolomide is a second-generation alkylating chemotherapeutic agent, introduced to therapy of primary brain tumors in the 1990s. It has since been approved for the therapy of recurrent and newly diagnosed malignant glioma. Temozolomide offers improved outcomes when used alone or in combination with irradiation. Its role in the therapy of other types of brain cancer, and specifically primary CNS lymphoma, continues to develop. This review will discuss the early stages of development of temozolomide, its introduction into the therapy of glioma, its role in the therapy of elderly patients, mechanisms of resistance and the evolution of its current and future applications.

Treatment of a case of phonological alexia with agraphia using the Auditory Discrimination in Depth (ADD) program

Phonological alexia and agraphia are acquired disorders characterized by an impaired ability to convert graphemes to phonemes (alexia) or phonemes to graphemes (agraphia). These disorders result in phonological errors typified by adding, omitting, shifting, or repeating phonemes in words during reading or graphemes when spelling. In developmental dyslexia, similar phonological errors are believed to result from deficient phonological awareness, an oral language skill that manifests itself in the ability to notice, think about, or manipulate the individual sounds in words. The Auditory Discrimination in Depth (ADD) program has been reported to train phonological awareness in developmental dyslexia and dysgraphia. We used a multiple-probe design to evaluate the ADD program's effectiveness with a patient with a mild phonological alexia and mixed agraphia following a left hemisphere infarction. Large gains in phonological awareness, reading and spelling nonwords, and reading and spelling real words were demonstrated. A follow-up reassessment, 2 months posttreatment, found the patient had maintained treatment gains in phonological awareness and reading, and attained additional improvement in real word reading.

Simultaneous detection of microorganisms in soil suspension based on PCR amplification of bacterial 16S rRNA fragments

The effect of buffer composition on simultaneous PCR amplification of 16S rRNA gene fragments of five bacterial species was examined using a number of different buffer systems. Tris-based PCR buffers at final concentrations of 10 mM proved unreliable. However, when the final concentration of Tris was increased to 75 mM, all five samples were routinely detected. The use of other buffers, 3-[(1,1-dimethyl-2-hydroxyethyl)amino]-2-hydroxypropanesulfonic acid (AMPSO) and 3-[cyclohexylamino]-2-hydroxy-1-propanesulfonic acid (CAPSO), resulted in PCR amplification of five products even at low final concentrations (10 mM). The presence of certain proteins in the amplification reaction could overcome an inhibitory effect seen when soil suspension was present in the reaction, as might occur when testing field samples for the presence of bacteria. Bovine serum albumin was found to be the most effective additive tested in overcoming inhibition.

The temporal evolution of striatal dopamine receptor binding and mRNA expression following hypoxia-ischemia in the neonatal rat

Neonatal hypoxic-ischemic (HI) brain injury in the rat alters dopamine receptors. To determine whether such changes are permanent, dopamine receptors and corresponding mRNA were examined at various time points after neonatal HI using receptor autoradiography and in situ hybridization. Rat pups underwent ligation of the left common carotid artery followed by hypoxic exposure (8.5% O2 for 3 h). Controls underwent sham surgery alone. Animals surviving for 2-80 days following HI were studied. Striatal D1 receptors (labeled by [3H]SCH23390) were reduced as early as 2 days following HI, remained depressed for 21 days, but recovered to control levels by young adulthood (3 months of age). D2 receptors (labeled by [125I] iodosulpride) did not decline until 10 days after HI, and remained uniformly depressed throughout the caudate-putamen thereafter. Changes in D1 receptor mRNA transcripts closely paralleled alterations in receptors: early reductions in D1 mRNA signal recovered by young adulthood. D2 mRNA exhibited a unique temporal profile with an early decrease (2 days following HI), and prompt, persistent recovery. Dopamine receptors and transcripts are differentially affected by HI injury early in development. Whereas D1 receptor expression recovers from neonatal HI injury, D2 receptors remain permanently affected despite the presence of normal levels of D2 receptor transcripts. A persistent, post-transcriptional effect of HI on D2 receptor expression is suggested.

Effect of neonatal hypoxia-ischemia on nigro-striatal dopamine receptors and on striatal neuropeptide Y, dynorphin A and substance P concentrations in rats

Perinatal hypoxic-ischemic brain injury was induced in 7- to 8-day-old rats by ligating the left carotid artery with subsequent exposure to 9% oxygen atmosphere for 2.5 h. The animals were killed 7 days later and grouped according to the degree of brain injury sustained after hypoxia-ischemia. Total protein content measured in striatum ipsilateral to the ligation, and dissected from brains showing extensive damage, was reduced to 64% of contralateral tissue. The protein content was not altered in other groups including control animals exposed to air and in sham-operated animals exposed to hypoxic conditions. The concentration of (pg/mg protein) and total (pg/striatum) striatal dynorphin A-like immunoreactivity (DLI) from brains with extensive damage were increased to 481% and 285% of the contralateral side, respectively. Hypoxia-ischemia increased striatal neuropeptide Y-like immunoreactivity (NPYLI) concentration from brains with extensive damage to 157% of contralateral side, but when the results were expressed as total NPYLI content per striatum, NPYLI content in striatum with extensive damage remained unaltered. Substance P-like immunoreactivity (SPLI) concentration and total content per striatum from brains with extensive damage were reduced to 66% and 43% of the contralateral side, respectively. D1 and D2 receptor density in animals killed 10 days after injury was reduced by 24% and 22% of control, respectively, in striatum from brains with extensive damage. These results indicate complex changes in brain neuropeptides following neonatal hypoxia-ischemia. Damage in the substance P system could have functional effects on dopaminergic transmission while the increase in NPYLI and in DLI concentrations may respectively reflect the relative preservation from neuronal damage and possibly an increase in neuropeptide synthesis or decrease in release. The decrease in SPLI concentration and the increase DLI concentration induced by hypoxia-ischemia suggests that these peptides may be present in separate neurons.

Motor neglect associated with a discrete parietal lesion

The syndrome of motor neglect may follow brain lesions affecting frontal, subcortical, and parietal structures. However, pure motor neglect has not been previously associated with a lesion confined to the parietal lobe. We observed a 79-year-old right-handed man with right-sided limb akinesia and motor neglect without concomitant sensory or visuospatial neglect. MRI showed a left posterior parietal infarct sparing the primary sensorimotor cortex. Transcranial magnetic stimulation showed comparable thresholds for electromyographic activation of the muscles of the right and left arm and normal central motor conduction times, indicating functional integrity of the motor cortex. This case demonstrates that a discrete parietal lesion can produce a pure intentional disorder, independent of sensory or visuospatial neglect.

Effects of hypoxic-ischemic brain damage on dopaminergic markers in the neonatal rat: a regional autoradiographic analysis

Dopamine has been implicated as an endogenous substance that may mediate neuronal death after hypoxic-ischemic insult. Using semiquantitative autoradiography, we studied the effect of perinatal hypoxic-ischemic injury on dopamine binding sites in rat brain. Experimental injury resulted in a substantial decrease in dopamine type-1 (D1) and forskolin (adenylate cyclase) binding sites. In contrast, markers for dopamine type-2 (D2) sites and for dopamine uptake were unaffected in lesioned animals. Changes within dopaminergic pathways were variable, with reduction in binding being encountered mainly in components of the extrapyramidal motor system: caudate-putamen, -61%; globus pallidus, -64%; entopeduncular nucleus, -60%; and substantia nigra, -69%. Furthermore, the topography of D1 receptor loss within the caudate-putamen was not uniform, with the greatest decrement in dorsolateral regions. Reduced D1 versus D2 receptor activation may underlie extrapyramidal movement disorders that appear as a consequence of perinatal hypoxic-ischemic insult.

From laboratory to clinic: the development of an immunological reagent

Access to a wide range of high quality and increasingly sophisticated reagents and equipment has underpinned the great surge of knowledge in basic immunology and the growing interest in clinical immunointervention. In this article, the first in an occasional series on immunological research and development in industry, Sue Bright and colleagues outline the key steps in a development programme to take a humanized monoclonal antibody into the clinic. The procedures involved in developing such reagents, particularly for clinical use, are long and require considerable ingenuity and scientific creativity.

Characterization and biodistribution of recombinant and recombinant/chimeric constructs of monoclonal antibody B72.3

B72.3 is a murine monoclonal antibody (IgG1) that recognizes a tumor-associated glycoprotein, termed TAG-72. B72.3 has been shown, using a variety of methodologies, to have a high degree of selective reactivity for colorectal, ovarian, lung, and breast carcinomas. Radiolabeled B72.3 has been administered both i.v. and i.p. in patients with colorectal and ovarian cancer as well as other carcinomas and has been shown to selectively bind to approximately 70-80% of metastatic lesions. Greater than 50% of the patients that have been treated with B72.3 have developed an immunological response to murine IgG after a single injection. In an attempt to minimize the immune response of these patients to the administered murine monoclonal antibody, we developed a recombinant form of the murine B72.3 as well as a recombinant/chimeric antibody, using the variable regions of the murine B72.3 and human heavy chain (gamma 4) and light chain (kappa) constant regions. We report here that both the recombinant B72.3 [rB72.3] and the recombinant/chimeric B72.3 [cB72.3(gamma 4)] IgGs maintain the tissue binding and idiotypic specificity of the native murine IgG. The native B72.3, rB72.3, and cB72.3(gamma 4) IgGs were radiolabeled and the biodistribution of these IgGs was studied in athymic mice bearing human colon carcinoma xenografts (LS-174T). Differences were observed between the cB72.3(gamma 4) and the native B72.3 in the percentage of injected dose/g that localized in the tumor. The somewhat lower absolute amounts of the cB72.3(gamma 4) in the tumor are mostly likely due to the observed more rapid clearance from the blood and body of the mouse as compared to the native B72.3 and rB72.3. All three forms [native B72.3, rB72.3, and cB72.3(gamma 4)] of the IgG, however, were able to localize the colon tumor with similar radiolocalization indices [percentage of injected dose/g in tumor divided by the percentage of injected dose/g in normal tissue].

Expression in COS cells of a mouse-human chimaeric B72.3 antibody

B72.3 is a mouse hybridoma cell-line secreting an IgG1 antibody which recognises an epitope on a tumour-associated antigen, TAG-72. This high molecular weight mucin-like molecule is found on a variety of human neoplasms, including colon, breast and ovarian carcinomas. Chimaeric immunoglobulin genes with the B72.3 specificity have been constructed by joining the mouse variable regions from cDNA clones to human genomic constant regions using recombinant DNA techniques. The chimaeric heavy and light chain immunoglobulin genes were placed under the control of a strong viral promoter, and co-transfected into COS-1 cells. SDS-PAGE analysis of the 35S-labelled products demonstrated that the transiently expressed antibodies were correctly synthesised and assembled. The specific binding characteristics of the parent B72.3 antibody were retained by the chimaeric antibody in an antigen-based ELISA. This system gave sufficiently high transient expression of the chimaeric antibody molecules to allow rapid physical and immunological characterisation of the engineered gene products.

Novel modified beta-interferons: gene cloning, expression, and biological activity in bacterial extracts

A series of novel, modified interferons based on the structure of human beta-interferon have been expressed in Escherichia coli. Modified interferon genes were constructed from sequences derived from the natural beta-interferon gene, a synthetic beta-interferon gene, or a specific combination of the two. A total of 23 out of the 25 novel interferons exhibited antiviral (AV) and antiproliferative (AP) activity which varied from 3 to 230% and 8 to 490% of the values for beta-interferon, respectively. None of the novel interferons had only AV or AP activity, although one had a much reduced ratio of AV/AP activity compared with beta-interferon. Substitution of beta-interferon amino acids 2-7 or 28-46 resulted in interferons with significantly increased AP activity on Daudi lymphoblastoid cells (four- to fivefold). All the novel interferons except two with modifications in the 82-105 region reacted with a neutralizing beta-interferon monoclonal antibody.

The effects of photoperiod and melatonin on serum prolactin levels of mink during the autumn molt

An experiment was conducted to determine the effects of a reduced daily photoperiod and exogenous melatonin on serum prolactin levels of mink during the autumn molt and growth of the winter pelage. During the last week of June, adult standard dark female mink (Mustela vision) were exposed to natural changes in daylength (controls), a reduced photoperiod of 6 h light: 18 h dark (6L:18D) or exposure to natural changes in daylength and treated with melatonin (10 mg) in a Silastic implant inserted subcutaneously over the scapular area. Beginning July 2, and continuing through October 22, blood samples were collected at nine biweekly intervals, and serum prolactin concentrations were quantified by a heterologous double antibody radioimmunoassay. Both reduced photoperiod and exogenous melatonin caused serum prolactin levels to decline rapidly after mid-July, resulting in concentrations that were significantly lower than those of controls 6 to 8 wk earlier. These data suggest that growth of the winter pelage of mink is strongly associated with declining prolactin levels. It appears that part of the photoperiodic-induced effects on fur growth of the mink are mediated through melatonin and its effects on prolactin synthesis and/or secretion.

Induction of winter fur growth in mink (Mustela vison) with melatonin

Adult and kit standard dark male and female mink were treated with 0, 5 or 10 mg melatonin, or a reduced photoperiod of 6 h light: 18 h dark (6L: 18D, initiated during the last week of June) to determine the effects of treatment on winter fur growth. Melatonin was administered in a Silastic implant inserted sc over the scapular region during the last week of June. Regardless of sex or age, mink treated with melatonin or a 6L: 18D photoperiod molted the summer pelage and grew the winter pelage earlier than controls (P less than .001). Winter pelage was fully prime by mid-October, 6 wk earlier than normal. Weight gain of mink, regardless of sex or age, was not affected by melatonin treatment. These findings indicate that photoperiodic effects on the growth of winter pelage in mink may be mediated through the pineal gland and its secretion of melatonin.

Prolactin binding sites in the uterus of the mink

The present study was conducted to determine if specific binding sites for prolactin (PRL) are present in the uterus of the mink. Uteri of anestrous mink were homogenized and subjected to differential centrifugation into three particulate fractions, 1500, 15 000 and 50 000 X g. Binding of [125I]oPRL to membranes in an aliquot (200-400 micrograms protein) of the 50 000 X g particulate fraction was quantified. Time and temperature for optimal binding were 18 h at 25 degrees C. Scatchard plot analysis revealed a single set of binding sites for PRL with a Kd of 8.25 X 10(-11) +/- 0.68 M. The maximum amount of [125I]oPRL bound was 28 fmoles/mg protein. Prolactin binding sites were detected in both the uterus and kidney of mink, but not in skeletal muscle, spleen, diaphragm or lung. These data indicate that uterine cell membranes of the mink contain sites that bind prolactin with high affinity.

Photoperiodic effects on serum glucocorticoids and fur growth in mink

The relationship of glucocorticoid secretion to artificial light-induced, early winter priming of pelage in ranch mink was investigated. On December 13, 1977, 16 mature female mink were exposed to natural light. On June 26, 1978, the animals were assigned randomly to one of two groups. Animals in Group 1 were housed in a light-control facility and subjected to 6 hr of artificial light daily and ambient temperatures until November 27, 1978. Animals in Group 2 served as controls and were exposed to natural light. Samples of blood and measurements of the fur and vulva were taken biweekly throughout the year. Concentrations of total glucocorticoids in serum were determined by competitive protein-binding assay. The pelage of mink reared under reduced artificial light was fully prime by October 31, while that of control animals did not become prime until November 27 (time x light regimen interaction, P less than .05). A seasonal effect (P less than .01) on total glucocorticoid concentrations in serum of control mink was revealed by a pattern of three peaks over the 12-month period. The pattern of glucocorticoid secretion was not affected by exposure of mink to reduced artificial light. Maximum concentrations of total glucocorticoids in serum occurred on the same date (September 5) in both groups, although levels were significantly higher in the light-treated mink (44.5 +/- 10.4 ng/ml) than in the controls 26.9 +/- 5.7 ng/ml). Fur growth was positively correlated with total glucocorticoid concentrations in serum during the period from June to December (overall r = .14, P less than .05). Both length and width of the vulva increased (P less than .01) during February and March in animals reared under natural light. These data suggest that the increased secretion of glucocorticoids induced by exposure of mink to reduced artificial light may be involved in promoting early priming of the winter pelage of these animals.

Biotin deficiency in mink fed spray-dried eggs

Young standard dark mink developed classical symptoms of biotin deficiency, including underfur-greying, "spectacle eye," loss of fur, exudates from eyes, nose and mouth and encrustation of paws, when fed a diet containing 10% commercially produced, denatured spray-dried eggs. Comparable animals fed 5% spray-dried eggs did not show these symptoms; however, their pelts tended to be browner (i.e., lighter colored), than those of control animals. The feeding period during which these symptoms developed covered about 4 1/2 months: August 1 to December 13. Supplemental biotin (1.34 and .45 mg d-biotin per kilogram dry feed) prevented deficiency symptoms in mink fed 10% spray-dried egg of 20% fresh frozen whole chicken eggs, respectively. Eye exudates were most severe in October, when the combined stress of body and fur growth was greatest, then showed a partial remission as peak growth of body tissue and fur was passed. It was concluded that spray-dried eggs are insufficiently heat-treated to render their avidin content inactive; thus they should be appropriately supplemented with biotin for use in mink diets.