Characterization of the human CD4+ T‐cell repertoire specific for major histocompatibility class I‐restricted antigens

While CD4⁺ T lymphocytes usually recognize antigens in the context of major histocompatibility (MHC) class II alleles, occurrence of MHC class‐I restricted CD4⁺ T cells has been reported sporadically. Taking advantage of a highly sensitive MHC tetramer‐based enrichment approach allowing detection and isolation of scarce Ag‐specific T cells, we performed a systematic comparative analysis of HLA‐A*0201‐restricted CD4⁺ and CD8⁺ T‐cell lines directed against several immunodominant viral or tumoral antigens. CD4⁺ T cells directed against every peptide‐MHC class I complexes tested were detected in all donors. These cells yielded strong cytotoxic and T helper 1 cytokine responses when incubated with HLA‐A2⁺ target cells carrying the relevant epitopes. HLA‐A2‐restricted CD4⁺ T cells were seldom expanded in immune HLA‐A2⁺ donors, suggesting that they are not usually engaged in in vivo immune responses against the corresponding peptide‐MHC class I complexes. However, these T cells expressed TCR of very high affinity and were expanded following ex vivo stimulation by relevant tumor cells. Therefore, we describe a versatile and efficient strategy for generation of MHC class‐I restricted T helper cells and high affinity TCR that could be used for adoptive T‐cell transfer‐ or TCR gene transfer‐based immunotherapies.     

Evaluation of Epstein-Barr Virus,Human Herpesvirus 6 (HHV-6), and HHV-8 Antiviral Drug Susceptibilities by Use of Real-Time-PCR-Based Assays

Evaluation of candidate antiviral drugs against Epstein-Barr virus (EBV), human herpesvirus 6 (HHV-6), and HHV-8 is hampered by the lack of convenient laboratory assays. We developed real-time quantitative PCR assays performed on supernatants of lymphoma cell lines and determined the 50% inhibitory concentrations (IC₅₀s) of nucleoside, nucleotide, and pyrophosphate analogues against these herpesviruses.     

A Novel Common Kell Antigen, TOU, and Its Spatial Relationship to Other Kell Antigens

A 47-year-old native American (TOU) was admitted to hospital for hip surgery. His serum agglutinated all red blood cells (RBCs) tested except Ko and DTT-treated RBCs and was weakly reactive with RBCs known to have a weak expression of Kell antigens, namely Kmod, McLeod, Kp(a+b-) (KEL:3,-4) and K:-13 (KEL:-13) phenotypes. RBCs from three siblings, a son and a daughter were incompatible with TOU's antibody. TOU's RBCs had the common Kell phenotype: K- k+ Kp(a-b+c-) Ku+ Js(a-b+) Ul(a-) K:11, -17 K:14,-24 K:12,13,18,19,22,-23 (KEL:-1,2,-3,4,5,-6,7,-10,11,12,13,14,-17,18,19,-21,22,-23,-24). Since TOU's RBCs were not agglutinated by an unidentified Kell-related antibody (IAN), tests were performed to show that TOU and IAN were mutually compatible. IAN is a Latino female hospitalised for a hysterectomy. The TOU antigen was shown to be located on the Kell glycoprotein by a monoclonal antibody immobilisation of erythrocyte antigen (MAIEA) assay. The unique pattern of reactivity obtained with TOU and IAN antibodies using this assay indicated the TOU epitope to be in an area remote from other Kell antigens, namely K, k, Kp^a, Kp^b, Kp^c, Ku, Js^a, Js^b, Ul^a, K11, K12, K13, K14, Wk^a, K18, K19, K22 and K24 (KEL1, KEL2, KEL3, KEL4, KEL5, KEL6, KEL7, KEL11, KEL12, KEL13, KEL14, KEL17, KEL18, KEL19, KEL21, KEL22 and KEL24) but close to the low-incidence antigen K23 (KEL23). Investigation of antibodies to previously identified antigens on the Kell glycoprotein by MAIEA using the mouse monoclonal antibodies BRIC18, BRIC68, BRIC107 and BRIC203 has identified six patterns of reactivity and has provided evidence for Kp^c being located in the same region as Kp^a and Kp^b.     

Development changes in the human cardiac isomyosin distribution: an immunohistochemical study using monoclonal antibodies

With monoclonal antibodies (Mab) specific for myosin heavy chain (MHC) isozymes, we have investigated the isomyosin content of atrial, ventricular and conductive fibers of 19 human fetuses (ranging from 14-36 weeks of gestation) and 3 newborns (2 days-2 weeks). In addition, the conduction system of 2 human adult hearts was studied. The fetal atrium is composed mostly of alpha-MHC during the first 23 weeks of gestation. beta-MHC is already expressed as traces at 14 weeks of gestation, and its expression increases progressively until birth, resulting in a great augmentation in beta-MHC. During this course, beta-MHC always predominates in certain areas (the crista terminalis and the interatrial septum) but not in other areas (the auricles). Preceding birth, the fetal ventricle is composed mostly of beta-MHC. From 14 weeks of gestation to birth, alpha-MHC is expressed in very rare fibers. Then, after birth, a large number of fibers simultaneously synthesize alpha-MHC. The AV node and His bundle system were labelled with anti-alpha and anti-beta Mab in fetal, newborn, and adult hearts with a double gradient of distribution: spatial (a higher proportion of alpha-containing fibers in the AV node than in the distal portion of the bundle of branches) and temporal (a higher proportion of alpha-containing fibers at a given point in fetal development than in the adult heart). One of the twenty-five hearts studied had an isomyosin distribution pattern not accorded to its age. Interestingly, it was clinically diagnosed as having idiopathic hypertrophic cardiomyopathy.     

Inactivation of AMPKα1 induces asthenozoospermia and alters spermatozoa morphology

AMP-activated protein kinase (AMPK), a key regulator of cellular energy homeostasis, is present in metabolic tissues (muscle and liver) and has been identified as a modulator of the female reproductive functions. However, its function in the testis has not yet been clearly defined. We have investigated the potential role of AMPK in male reproduction by using transgenic mice lacking the activity of AMPK catalytic subunit α1 gene [α1AMPK knockout (KO)]. In the testis, the α1AMPK subunit is expressed in germ cells and also in somatic cells (Sertoli and Leydig cells). α1AMPK KO male mice show a decrease in fertility, despite no clear alteration in the testis morphology or sperm production. However, in α1AMPK(-/-) mice, we demonstrate that spermatozoa have structural abnormalities and are less motile than in control mice. These spermatozoa alterations are associated with a 50% decrease in mitochondrial activity, a 60% decrease in basal oxygen consumption, and morphological defects. The α1AMPK KO male mice had high androgen levels associated with a 5- and 3-fold increase in intratesticular cholesterol and testosterone concentrations, respectively. High concentrations of proteins involved in steroid production (3β-hydroxysteroid dehydrogenase, cytochrome steroid 17 alpha-hydroxylase/17,20 lysate, and steroidogenic acute regulatory protein) were also detected in α1AMPK(-/-) testes. In the pituitary, the LH and FSH concentrations tended to be lower in α1AMPK(-/-) male mice, probably due to the negative feedback of the high testosterone levels. These results suggest that total α1AMPK deficiency in male mice affects androgen production and quality of spermatozoa, leading to a decrease in fertility.     

Auditory temporal envelope processing in a patient with left-hemisphere damage

Abstract

Auditory temporal envelope processing was investigated in a patient showing a mild speech identification impairment following left-hemisphere damage. Three tasks evaluated the patient's ability to: (1) detect a sinusoidal amplitude modulation (SAM) applied to a white noise, as a function of modulation rate (i.e. her ‘temporal modulation transfer function’ or TMTF); (2) discriminate between two white noises amplitude modulated by time-reversed temporally asymmetric envelopes; and (3) identify white noises amplitude modulated by the temporal envelope of speech stimuli. Measurements of intensity discrimination thresholds were performed as a control task. Compared to normal data, the results obtained with the brain-damaged patient showed: (1) increased thresholds for the detection of SAM; (2) increased thresholds for the discrimination of temporal asymmetry; and (3) a deficit in the identification of speechenvelope noise stimuli. In contrast, intensity discrimination thresholds were within the normal range. Taken together, the results indicate a general impairment in auditory temporal acuity, which is now specified as a deficit in the coding of envelope rate and shape, and a deficit in the ability to use temporal envelope cues in speech processing. These results support the hypothesis that left-hemisphere damage is associated with an impairment in time analysis, which may cause, in turn, speech intelligibility disorders.     

An oral hygiene brochure for your implant overdenture patients

Although there may not be a direct association between oral hygiene and implant failure, oral hygiene must be maintained around implants in the edentulous mouth. Bacterial plaque on dentures can act as a reservoir for pathogens that cause respiratory disease. Unfortunately, many edentulous patients have poor oral hygiene. In this article, we describe the development of a brochure to educate patients wearing mandibular overdentures supported by 2 implants as a supplement to the dentist"s verbal instructions. Dental literature and several specialists were consulted during preparation of the brochure, which contains photographs accompanying oral hygiene instructions. It was sent to 25 participants who were subsequently called and questioned regarding its content and their oral hygiene habits. The 24 respondents found the brochure useful; most reported that they would keep the brochure for future reference and that they learned something new about how to maintain their implants properly. No one found the brochure too long or unclear. Most participants read the brochure entirely, rather than skimming it. The brochure is available to all clinicians who wish to incorporate this tool into their implant overdenture therapeutic approach.