Mucosal-associated invariant T-cell activation and accumulation after in vivo infection depends on microbial riboflavin synthesis and co-stimulatory signals.

Despite recent breakthroughs in identifying mucosal-associated invariant T (MAIT) cell antigens (Ags), the precise requirements for in vivo MAIT cell responses to infection remain unclear. Using major histocompatibility complex-related protein 1 (MR1) tetramers, the MAIT cell response was investigated in a model of bacterial lung infection employing riboflavin gene-competent and -deficient bacteria. MAIT cells were rapidly enriched in the lungs of C57BL/6 mice infected with Salmonella Typhimurium, comprising up to 50% of αß-T cells after 1 week. MAIT cell accumulation was MR1-dependent, required Ag derived from the microbial riboflavin synthesis pathway, and did not occur in response to synthetic Ag, unless accompanied by a Toll-like receptor agonist or by co-infection with riboflavin pathway-deficient S. Typhimurium. The MAIT cell response was associated with their long-term accumulation in the lungs, draining lymph nodes and spleen. Lung MAIT cells from infected mice displayed an activated/memory phenotype, and most expressed the transcription factor retinoic acid-related orphan receptor γt. T-bet expression increased following infection. The majority produced interleukin-17 while smaller subsets produced interferon-γ or tumor necrosis factor, detected directly ex vivo. Thus the activation and expansion of MAIT cells coupled with their pro-inflammatory cytokine production occurred in response to Ags derived from microbial riboflavin synthesis and was augmented by co-stimulatory signals.

Overcoming the poor immunogenicity of a protein by DNA immunization as a fusion construct.

The production of antibodies against poorly immunogenic proteins is problematic. Often there is a failure to generate such antibodies. Furthermore, antibodies against other specificities are frequently induced. We describe a simple approach, analogous to conjugation to a protein carrier, whereby immunization with naked DNA was used to raise antibody to a highly homologous and poorly immunogenic allotypic protein. Deoxyribonucleic acid encoding the protein of interest was fused to DNA encoding the Fc region of a foreign Ig, resulting in increased immunogenicity. The potential applications of this approach include the production of antisera and mAb to allotypic variants, mutant proteins, and proteins that are highly conserved between species.

Nucleic acid vaccines: tasks and tactics.

There are no adequate vaccines against some of the new or reemerged infectious scourges such as HIV and TB. They may require strong and enduring cell-mediated immunity to be elicited. This is quite a task, as the only known basis of protection by current commercial vaccines is antibody. As DNA or RNA vaccines may induce both cell-mediated and humoral immunity, great interest has been shown in them. However, doubt remains whether their efficacy will suffice for their clinical realization. We look at the various tactics to increase the potency of nucleic acid vaccines and divided them broadly under those affecting delivery and those affecting immune induction. For delivery, we have considered ways of improving uptake and the use of bacterial, replicon or viral vectors. For immune induction, we considered aspects of immunostimulatory CpG motifs, coinjection of cytokines or costimulators and alterations of the antigen, its cellular localization and its anatomical localization including the use of ligand-targeting to lymphoid tissue. We also thought that mucosal application of DNA deserved a separate section. In this review, we have taken the liberty to discuss these enhancement methods, whenever possible, in the context of the underlying mechanisms that might argue for or against these strategies.

McLeod neuroacanthocytosis: genotype and phenotype.

McLeod syndrome is caused by mutations of XK, an X-chromosomal gene of unknown function. Originally defined as a peculiar Kell blood group variant, the disease affects multiple organs, including the nervous system, but is certainly underdiagnosed. We analyzed the mutations and clinical findings of 22 affected men, aged 27 to 72 years. Fifteen different XK mutations were found, nine of which were novel, including the one of the eponymous case McLeod. Their common result is predicted absence or truncation of the XK protein. All patients showed elevated levels of muscle creatine phosphokinase, but clinical myopathy was less common. A peripheral neuropathy with areflexia was found in all but 2 patients. The central nervous system was affected in 15 patients, as obvious from the occurrence of seizures, cognitive impairment, psychopathology, and choreatic movements. Neuroimaging emphasized the particular involvement of the basal ganglia, which was also detected in 1 asymptomatic young patient. Most features develop with age, mainly after the fourth decade. The resemblance of McLeod syndrome with Huntington's disease and with autosomal recessive chorea-acanthocytosis suggests that the corresponding proteins--XK, huntingtin, and chorein--might belong to a common pathway, the dysfunction of which causes degeneration of the basal ganglia.

Delayed rejection of fetal pig pancreas in CD4 cell deficient mice was correlated with residual helper activity.

CD4 cells have been shown to play a dominant role in the rejection of xenografts. Depletion of murine CD4 cells by injecting anti-CD4 antibody prolongs the graft survival, but does not prevent its rejection. For a more stable phenotype, we used genetically modified mice. To test whether the delayed rejection is caused by incomplete depletion of CD4 cells, we evaluated the response to fetal pig pancreas (FPP) xenografts in three types of CD4 cell deficient mice. They are MHC class II deficient mice (MHC II(o/o), CD4 deficient mice (CD4(o/o)) and a novel type of CD4 cell deficient mice (designated GK). GK mice were rendered permanently and completely CD4 deficient by transgenic expression of anti-CD4 antibody, whereas both MHC II(o/o) and CD4(o/o) mice have a residual helper cell population. FPP grafts in wild type mice were rejected within a week, whereas FPP grafts survived up to 4 weeks in MHC II(o/o) and CD4(o/o) mice. Survival of grafts in GK mice was even longer (8 weeks). Differences in histology were also noted. Rejecting grafts in MHC II(o/o) and wild-type mice were infiltrated with both eosinophils and mononuclear cells, whereas the infiltrates in CD4(o/o) and GK mice were exclusively mononuclear cells. Immunohistochemistry showed that they were primarily CD8 cells. The immune response to FPP was clearly different in the three types of CD4 cell deficient mice. Splenocytes of MHC II(o/o) 3 weeks post-transplant with FPP produced substantial amounts of IFN-gamma and IL-5, whereas splenocytes of CD4(o/o) mice produced low levels of IFN-gamma but no detectable IL-5. At similar times, these cytokines were not detected in GK mice. Furthermore, CD4(o/o) mice were capable of mounting helper dependent, although reduced, IgG responses to FPP antigens, while GK mice were not. The above results indicate that residual helper activity in some types of CD4 cell deficient mice could still contribute to xenograft rejection. Caution needs to be exercised where such mice are used as models of CD4 cell deficiency. Also, because there is eventual rejection of xenograft FPP in GK mice which lack detectable helper activity, we argue that these mice are a better model to investigate the involvement of CD4-independent rejection mechanisms.

CD4 help-independent induction of cytotoxic CD8 cells to allogeneic P815 tumor cells is absolutely dependent on costimulation.

Mice made transgenic (Tg) for a rat anti-mouse CD4 Ab (GK mice) represent a novel CD4-deficient model. They not only lack canonical CD4 cells in the periphery, but also lack the residual aberrant Th cells that are found in CD4-/- mice and MHC class II-/- mice. To analyze the role of CD4 help and costimulation for CTL induction against alloantigens, we have assessed the surface and functional phenotype of CD8 cells in vivo (e.g., clearance of allogeneic P815 cells) and in vitro. In our CD4-deficient GK mice, CTL responses to allogeneic P815 cells were induced, albeit delayed, and were sufficient to eliminate P815 cells. Induction of CTL and elimination of allogeneic P815 cells were inhibited both in the presence and absence of CD4 cells by temporary CD40 ligand blockade. This indicated that direct interaction of CD40/CD40L between APCs and CD8 cells may be an accessory signal in CTL induction (as well as the indirect pathway via APC/CD4 interaction). Furthermore, whereas in CTLA4Ig single Tg mice P815 cells were rejected promptly, in the double Tg GK/CTLA4Ig mice CTL were not induced and allogeneic P815 cells were not rejected. These findings suggest that CD40/CD40L is involved in both CD4-dependent and CD4-independent pathways, and that B7/CD28 is pivotal in the CD4-independent pathway of CTL induction against allogeneic P815 cells.

Meningeal involvement in Wegener's granulomatosis.

We describe a rare neurological manifestation of Wegener's granulomatosis, meningeal involvement, which occurred despite therapy resulting in disease quiescence in other organs. Clinical, radiographic, and neuropathological features are described.

A patient with mania and photoconvulsive epilepsy.

OBJECTIVE: To describe a young patient who had a comorbidity of mania and photoconvulsive epilepsy. CLINICAL PICTURE: This patient presented with a clinical picture of mania which proved difficult to treat until an EEG revealed the presence of photoconvulsive epilepsy. TREATMENT: Treatment with haloperidol and lithium was unsuccessful but the addition of carbamazepine produced a dramatic response. Haloperidol was stopped and the patient maintained on lithium and carbamazepine. OUTCOME: A successful outcome was achieved with carbamazepine and the patient has remained well on this treatment for 2 years. CONCLUSIONS: The authors postulate that there may be an association between photoconvulsive epilepsy and mania, perhaps on a kindling basis. The literature pertaining to the psychiatric aspects of photoconvulsive epilepsy is reviewed.

Calcification of cervical ganglia: case report.

We describe a 44-year-old woman with progressive cervical pain in whom plain films of the cervical spine showed only minor syndesmophyte formation when the patient first presented. However, after 5 weeks, repeat films demonstrated heavy symmetrical calcification of the cervical dorsal root ganglia. A review of the literature did not reveal a previous description of these findings.

Frontal signs following subcortical infarction.

Subcortical cerebral infarction is associated with impaired performance on tests of cognitive function which are sensitive to frontal lobe damage. In a cohort of 82 patients with multiple subcortical cerebral infarcts diagnosed on the basis of CT scan appearances, physical signs presumed to be sensitive to frontal lobe dysfunction were elicited. Associations between physical findings and CT scan changes were determined. The snout reflex was present in 38 patients and correlated significantly with the number of lesions, the presence of periventricular lucency and the presence of ventricular enlargement, while the grasp reflex occurred in 33 and correlated with the number of lesions and the presence of ventricular enlargement, and gait impairment in 54 correlated with the number of lesions and the presence of ventricular enlargement. It is assumed that multiple subcortical infarcts disrupt frontal association pathways, resulting in frontal disconnection which produces frontal cognitive dysfunction and frontal release signs.

Eosinophilic meningitis: cause of a chronic pain syndrome.

Three tourists developed eosinophilic meningitis after visiting the Fijian Islands. Two had a severe and long lasting illness with chronic intractable pain. In one patient electrophysiological studies and MRI scan of the brain were abnormal and provided evidence of both radicular and cerebral parenchymal involvement by the most likely causative agent, Angiostrongylus cantonensis.

Perineural spread of cutaneous head and neck cancer. Its orbital and central neurologic complications.

The ability of cutaneous squamous cell carcinoma of the face to cause ophthalmoplegia or central nervous system dysfunction via perineural spread is not well recognized. Five patients presenting to a general neurology unit are described in whom partial or complete ophthalmoplegia developed following fifth and seventh cranial nerve involvement by cutaneous squamous cell carcinoma. Two patients subsequently developed a contralateral hemiparesis; and one, multiple cranial nerve palsies as the tumor spread centrally. Normal radiologic findings or complete healing of the primary skin lesion caused delay in the diagnosis in three of the patients. When ophthalmoplegia or central nervous system dysfunction develops as a consequence of perineural spread of cutaneous facial cancer, management is palliative.

Cognitive and motor dysfunction in Parkinson's disease. Clinical, performance, and computed tomographic correlations.

The neuropathologic and pathophysiological relationship of specific to more generalized cognitive dysfunction in Parkinson's disease (PD) remains incompletely understood. This issue was examined in a study of 39 patients with PD, utilizing standardized clinical measures, computerized neuropsychological tests, and quantitative computed tomography. Disorders of visuospatial discrimination and perceptual-motor function closely paralleled motor scores, suggesting a common neuropathologic basis. Caudate nuclear and mesocortical dopamine depletion play a role in this context. More generalized cognitive dysfunction occurred in older patients with a somewhat longer disease duration, more advanced parkinsonism, and computed tomographic evidence of subcortical and frontal cortical atrophy but without significant cerebral atrophy when compared with age-matched controls. Further prospective clinicopathologic studies will be required to clarify the relative contribution of the primary dopaminergic dysfunction, age-related changes, Alzheimer-type pathologic condition, and other coexisting neurotransmitter deficits to the dementia seen in PD.

Protein metabolism in Duchenne muscular dystrophy, monoclonal and mixed skeletal muscle cultures.

Previous studies have suggested that accelerated protein degradation or a reduced rate of protein synthesis is the process responsible for muscle wasting in Duchenne dystrophy. Skeletal muscle biopsies were obtained from 4 Duchenne dystrophy and 6 normal male orthopaedic control patients. Muscle cultures were established from dissociated single cells and protein metabolism was studied in mixed, confluent, post-fusion cultures. The rate of total protein synthesis was significantly greater in Duchenne cultures, while the degradation rate of long half-life protein was not significantly different in Duchenne dystrophy and control cultures. Monoclonal cultures from 1 Duchenne and 1 control biopsy demonstrated considerable variation in protein synthesis and degradation rates and creatine kinase activity between clones from each biopsy. This suggests that individual myoblasts differ significantly in growth and myogenic potential.

Insulin resistance and regulation of serum amino acid levels in myotonic dystrophy.

To quantify the degree of whole body insulin resistance in patients with myotonic dystrophy and to determine if these same patients display signs of a whole body decrease in the action of insulin on amino acid uptake and glucose disposal, three separate 120 min studies employing the euglycaemic insulin clamp technique (20, 80 and 200 m-units min-1 m-2) were performed on five ambulatory patients with myotonic dystrophy. The results were compared with findings obtained in identical studies in 21 normal volunteers. Myotonic dystrophy patients showed a slower, less marked decline in the serum concentration of insulin sensitive amino acids (threonine, valine, leucine, isoleucine, tyrosine, phenylalanine) during all three insulin infusions compared with normals. The greatest difference occurred at the low physiological elevations of insulin produced by the 20 m-units min-1 m-2 infusion. Alanine levels fell significantly below baseline in patients with myotonic dystrophy after 60 and 120 min of insulin infusion with all three rates of insulin infusion. Normal subjects had only a minimal, insignificant decline in arterialized alanine concentrations during the three different insulin infusions. Creatinine adjusted rates of whole body glucose disposal were 30-40% lower in the myotonic dystrophy group at all three doses of insulin compared with the normals. This demonstrates that their insulin resistance was not due simply to a reduction in muscle mass. The overall pattern of findings in these studies of patients with myotonic dystrophy indicates that there is a whole body derangement in the regulation of circulating amino acid levels by insulin as well as a marked decrease in the action of this hormone in stimulating glucose uptake by target tissues.

Acalculia following a dominant-hemisphere subcortical infarct.

A 60-year-old, right-handed woman experienced persistent impairment of calculating ability following a subcortical infarct involving the head of the left caudate nucleus, the anterior superior putamen, and the anterior limb of the internal capsule extending superiorly into the periventricular white matter. Acalculia resulted from defects of numerical syntax, the loss of ability to manipulate mathematical concepts, and impaired working memory.

Reye syndrome associated with aspirin therapy for systemic lupus erythematosus.

A 14-year-old girl in whom Reye syndrome developed during aspirin therapy for an inflammatory disorder proven to be systemic lupus erythematosus is reported. This case and similar cases of Reye syndrome in patients with juvenile rheumatoid arthritis suggest that an etiologic relationship exists between salicylate therapy and Reye syndrome in children with collagen vascular disorders.

Whole body insulin resistance in myotonic dystrophy.

To quantitate the degree of whole body insulin resistance in patients with myotonic dystrophy, three separate euglycemic insulin infusions were given to ambulatory patients and the results compared with findings in normal control subjects. Basal glucose and insulin values were similar for the two groups. There was no significant difference in insulin clearance rates between normal subjects and patients at the three insulin infusion rates used. A highly significant decrease in the whole body glucose disposal rate was seen during the 120-minute insulin infusion in the patients with myotonic dystrophy compared with normal subjects at all three insulin dosages (20 mU/m2/min: 2.18 +/- 0.29 [standard error] versus 5.49 +/- 1.72 mg/kg/min, p less than 0.0001; 80 mU/m2/min: 4.16 +/- 0.34 versus 8.49 +/- 0.45 mg/kg/min, p less than 0.0001; 200 mU/m2/min: 5.22 +/- 0.53 versus 10.06 +/- 0.50 mg/kg/min, p less than 0.0001). These marked decreases in glucose disposal rates for the patients were adjusted in accordance with their 24-hour urinary creatinine excretion rate to correct for the difference in muscle mass between patients and controls. This adjusted glucose disposal rate was 15 to 25% lower (p less than 0.02) in the patients with myotonic dystrophy at insulin infusion rates of 20 and 80 mU. During the 200 mU insulin infusions, the adjusted glucose disposal rate remained lower than that in normal subjects but was of borderline statistical significance. These studies suggest that moderately severe whole body insulin resistance is responsible for the postprandial hyperinsulinemia typically seen in patients with myotonic dystrophy.