Flagellar filament structural protein induces Sjögren's syndrome-like sialadenitis in mice.

OBJECTIVE: Sjögren's syndrome (SS) is a systemic autoimmune disease that primarily affects lacrimal and salivary glands. We previously reported that FliC derived from Escherichia coli could induce autoimmune pancreatitis-like lesions. From these results, we speculated that FliC could also induce SS-like exocrinopathy. In this study, we investigated the effects of chronic exposure to FliC on lacrimal and salivary glands and the possibility that it might lead to an autoimmune response. METHODS: C57BL/6 mice were repeatedly injected with FliC and histological changes, serum levels of cytokine/chemokines and autoantibodies were evaluated at different time points after the final injection. The presence of sialadenitis was diagnosed by histological methods. RESULTS: In FliC-treated groups, 57% of subjects developed inflammatory cell infiltrates around ducts in mandibular salivary glands, but not lacrimal glands. In addition, serum levels of total IgG, IgG1, and IgG2a were significantly higher in FliC-treated groups. Intriguingly, serum anti-SSA/Ro levels were also significantly higher in FliC-treated groups. Cytokine analysis revealed that serum levels of IL-1ß, IL-12p70, IL-13, IFN-γ, IL-15, and IL-23 seemed to be higher in FliC-treated mice. CONCLUSIONS: Our data suggest that FliC-treated mice develop an SS-like phenotype. Our model may elucidate the relationship between commensal bacteria and SS.

Effect of Lipopolysaccharide on the Progression of Non-Alcoholic Fatty Liver Disease in High Caloric Diet-Fed Mice.

The incidence of non-alcoholic steatohepatitis (NASH) is increasing. Because gut microbiota have been highlighted as one of the key factors in the pathogenesis of metabolic syndrome, we investigated the involvement of the bacterial component in the progression of non-alcoholic fatty liver (NAFL) to NASH. C57BL/6 mice were fed with maintenance food (MF, groups A and B) or a high caloric diet (HCD, groups C and D) for 1 month. Mice were then divided into four groups: Groups A and C were inoculated with PBS, while groups B and D were inoculated with lipopolysaccharide (LPS) plus complete Freund's adjuvant (CFA). The inoculations were performed a total of 3 times over 3 months. At 6 months, while hepatic steatosis was observed in groups C and D, cellular infiltration and fibrosis were less evident in group C than in group D. Inflammatory cytokines were upregulated in groups B and D. 16S rRNA pyrosequencing of whole colon homogenates containing faeces showed that certain bacterial groups, such as Bacteroidaceae, Peptostreptococcaceae and Erysipelotrichaceae, were increased in groups C and D. Although loading of bacterial components (LPS) resulted in hepatic inflammation in both MF- and HCD-fed mice, HCD feeding was more crucial in the progression of NAFL during the triggering phase.

Ecology of Increasing Diseases: Population Growth and Environmental Degradation.

The World Health Organization (WHO) and other organizations report that the prevalence of human diseases during the past decade is rapidly increasing. Population growth and the pollution of water, air, and soil are contributing to the increasing number of human diseases worldwide. Currently an estimated 40% of world deaths are due to environmental degradation. The ecology of increasing diseases has complex factors of environmental degradation, population growth, and the current malnutrition of about 3.7 billion people in the world.

A prospective randomized comparative study on the safety and tolerability of transnasal esophagogastroduodenoscopy.

BACKGROUND AND STUDY AIM: Transnasal esophagogastroduodenoscopy (EGD) with a small-caliber endoscope is well tolerated by patients. However, the effect of this procedure on cardiopulmonary function has not been fully investigated. The aim of this prospective, randomized study was to investigate the effect of transnasal EGD in comparison with transoral EGD on cardiopulmonary function. PATIENTS AND METHODS: The study involved 450 patients referred for diagnostic EGD. Patients were randomly assigned to one of three types of unsedated EGD (150 patients per group): transnasal EGD using a small-caliber endoscope (the "XP-N" group), transoral EGD using the same small-caliber endoscope ("XP-O" group), and transoral EGD using a conventional endoscope ("XQ" group). Systolic and diastolic blood pressure, pulse rate, and arterial oxygen saturation were monitored before, and 2, 4 and 6 minutes after intubation, and just after endoscope extubation. Gagging episodes were also counted, to determine tolerance. RESULTS: It was not possible to perform transnasal EGD in 12 patients (8.0%). A small amount of epistaxis was observed in eight (5.8%) of 138 patients who were examined successfully by transnasal EGD. Systolic and diastolic blood pressure, pulse rate, rate-pressure product (pulse rate x systolic blood pressure/100), and the drop in arterial oxygen saturation in the XQ group were significantly greater than in the XP-N and XP-O groups at each time point. In the XP-N group, these parameters were significantly lower than those in the XP-O group at 2 minutes after intubation. Of the tree groups the number of gagging episodes was significantly lower in the XP-N group. CONCLUSION: Transnasal EGD is safer than transoral EGD as it is associated with fewer adverse effects on cardiopulmonary function and is better tolerated by patients.

Gamma/delta T cells provide innate immunity against renal cell carcinoma.

Host immune function plays a certain role against the development of renal cell carcinomas (RCCs), but the mechanism is not entirely understood. Human gamma/delta (gamma/delta) T cells defend the body against infection. In this study, we clarify the role of gamma/delta T cells in the surveillance system against RCCs by analyzing the gamma/delta T cells in peripheral blood mononucleocytes (PBMs) and tumor infiltrating lymphocytes (TILs) from 41 patients with RCCs. The results showed that the number of gamma/delta T cells expressing V gamma 2 and V delta 2 in variable elements of TCR was elevated in the PBMs in 10 patients, but not in any of 32 healthy individuals. The proportion of patients with an elevated number of gamma/delta T cells (> 10%) increased with cancer stage. The level of the gamma/delta T cells decreased after surgery. The gamma/delta T cells in the TILs were more activated than those in the PBMs. Evaluation of the junctional diversity of TCR V gamma 2 and V delta 2 chains showed that the increased peripheral blood gamma/delta T cells were oligoclonal rather than polyclonal. Taken together, our findings suggest that gamma/delta T cells recognize certain RCC-related antigens and play a role in the surveillance system against RCCs.

Functional uncoupling of T-cell receptor engagement and Lck activation in anergic human thymic CD4+ T cells.

Human thymic CD1a-CD4+ T cells in the final stage of thymic maturation are susceptible to anergy induced by a superantigen, toxic shock syndrome toxin-1 (TSST-1). Thymic CD4+ T-cell blasts, established by stimulating human thymic CD1a-CD4+ T cells with TSST-1 in vitro, produce a low level of interleukin-2 after restimulation with TSST-1, whereas TSST-1-induced adult peripheral blood (APB) CD4+ T-cell blasts produce high levels of interleukin-2. The extent of tyrosine phosphorylation of the T-cell receptor zeta chain induced after restimulation with TSST-1 was 2-4-fold higher in APB CD4+ T-cell blasts than in thymic CD4+ T-cell blasts. The tyrosine kinase activity of Lck was low in both thymic and APB CD4+ T-cell blasts before restimulation with TSST-1. After restimulation, the Lck kinase activity increased in APB CD4+ T-cell blasts but not in thymic CD4+ T-cell blasts. Surprisingly, Lck was highly tyrosine-phosphorylated in both thymic and APB CD4+ T-cell blasts before restimulation with TSST-1. After restimulation, it was markedly dephosphorylated in APB CD4+ T-cell blasts but not in thymic CD4+ T-cell blasts. Lck from APB CD4+ T-cell blasts bound the peptide containing the phosphotyrosine at the negative regulatory site of Lck-505 indicating that the site of dephosphorylation in TSST-1-activated T-cell blasts is Tyr-505. Confocal microscopy demonstrated that colocalization of Lck and CD45 was induced after restimulation with TSST-1 in APB CD4+ T-cell blasts but not in thymic CD4+ T-cell blasts. Further, remarkable accumulation of Lck in the membrane raft was observed in restimulated APB CD4+ T-cell blasts but not in thymic CD4+ T-cell blasts. These data indicate that interaction between Lck and CD45 is suppressed physically in thymic CD4+ T-cell blasts and plays a critical role in sustaining an anergic state.

Identification of a new type of invariant V alpha 14+ T cells and responsiveness to a superantigen, Yersinia pseudotuberculosis-derived mitogen.

We examined the expression of the H4 T cell activation marker in thymic T cell subpopulations and found that TCR-alpha beta+ CD4+ thymic T cells are segregated into three subpopulations based upon H4 levels. Thymic T cells with either no or low H4 expression differentiate via the mainstream differentiation pathway in the thymus. H4int thymic T cells, which express a skewed V beta repertoire of V beta 2, -7, and -8 in their TCRs, show the phenotype of NKT cells: CD44high, Ly6Chigh, NK1.1+, and TCR-alpha beta low. H4high thymic T cells also show a skewed V beta repertoire, V beta 2, -7, and -8, and predominantly express an invariant V alpha 14-J alpha 281+ alpha-chain in their TCRs but constitute a distinct population in that they are CD44int, Ly6C-, NK1.1-, and TCR-alpha beta high. Thus, invariant V alpha 14+ thymic T cells consist of ordinary NKT cells and a new type of T cell population. V beta 7+ and V beta 8.1+ invariant V alpha 14+ thymic T cells are present in DBA/2 mice, which carry mammary tumor virus-7-encoded superantigens, in comparable levels to those in BALB/c mice. Furthermore, V beta 7+ invariant V alpha 14+ thymic T cells in DBA/2 mice are in the immunologically responsive state, and Yersinia pseudotuberculosis-derived mitogen-induced V beta 7+ invariant V alpha 14+ thymic T cell blasts from DBA/2 and BALB/c mice exhibited equally enhanced responses upon restimulation with Y. pseudotuberculosis-derived mitogen. Thus, invariant V alpha 14+ thymic T cells that escape negative selection in DBA/2 mice contain T cells as functionally mature as those in BALB/c mice.

Enhanced hepatocyte growth factor expression associated with prolonged rat hepatic allograft survival in recipients pretreated with donor-specific blood.

BACKGROUND: Pretransplantation injection of freshly heparinized donor blood (donor-specific blood transfusion, or DST) significantly prolongs the survival of hepatic allografts from ACI(RT1a) to LEW(RT1l) rats. We investigated hepatocyte growth factor (HGF) expression in rat hepatic allografts of recipients pretreated with or without DST. METHODS: The levels of HGF mRNA and protein in hepatic allografts were determined after transplantation. The localization of HGF+ cells was identified with a rat anti-HGF monoclonal antibody. RESULTS: Plasma HGF concentrations in transplanted rats treated with DST were significantly and persistently increased compared to untreated rats with hepatic allografts. The number of HGF+ cells in hepatic allografts of recipients pretreated with DST on day 14 was significantly greater than that in allografts of untreated recipients on day 7. HGF+ cells were also found in the marginal zone and red pulp of recipient spleens. Northern blot analysis revealed the presence of three HGF+ cell phenotypes: HGF+ED1+, HGF+ED2+, and HGF+ED1-ED2-. Most HGF+ cells were ED1-ED2-. In situ hybridization demonstrated HGF mRNA in the mononuclear cells in the portal and sinusoidal areas as well as the marginal zone and red pulp in both DST-treated and untreated recipient spleens. CONCLUSIONS: Enhanced HGF expression in rat hepatic allografts is associated with immunologic unresponsiveness induced by DST.

Inhibition of a hyperpolarization-activated current by clonidine in rat dorsal root ganglion neurons.

Whole cell voltage- and current-clamp recordings were carried out to investigate the effects of clonidine, an alpha 2-adrenoceptor agonist, in L4 and L5 dorsal root ganglion (DRG) neurons of the rat. In voltage-clamp mode, application of 20 microM clonidine reversibly reduced the inward current evoked by hyperpolarizing voltage steps. The "clonidine-sensitive current" was obtained by subtracting the current during clonidine application from the control current, and its properties were as follows. 1) It was a slowly activating inward current evoked by hyperpolarization. 2) The reversal potential in the standard extracellular solution ([K+]o = 5 mM, [Na+]o = 151 mM) was -38.3 mV, and reduction of [Na+]o shifted it to a more negative potential, whereas an increase of [K+]o shifted it to a more positive potential, indicating that the current was carried by Na+ and K+ (PNa/PK = 0.22). 3) The relationship between the chord conductance underlying the clonidine-sensitive current and voltage could be fitted by a Boltzmann equation. These results indicate that the clonidine-sensitive current corresponds to a hyperpolarization-activated current (Ih), i.e., clonidine inhibits Ih in rat DRG neurons. DRG neurons were classified as small (15.9-32.9 microns diam), medium-sized (33-42.9 microns), and large (43-63.6 microns), and 7 of 19, 24 of 25, and 22 of 22 of these types exhibited Ih with mean +/- SE clonidine-induced inhibition values of 36.1 +/- 3.5% (n = 7), 43.1 +/- 3.7% (n = 24), and 35.1 +/- 2.7% (n = 22), respectively. Clonidine application to L4 and L5 DRG neurons excised from rats the sciatic nerves of which had been transected 14-35 days previously (transected DRG neurons) also reduced Ih. In current-clamp mode, 9 of 13 intact and 4 of 6 transected medium-sized DRG neurons that exhibited Ih responded to clonidine with hyperpolarization (> 2 mV). Some medium-sized DRG neurons exhibited repetitive action potentials in response to a depolarizing current pulse, and clonidine reduced the firing discharge frequencies in 8 of 11 intact and 3 of 4 transected neurons tested. Injection of a hyperpolarizing current pulse produced time-dependent rectification in DRG neurons that exhibited Ih, and clonidine blocked this rectification in all intact and transected neurons tested. These results suggest that inhibition of Ih due to alpha 2-adrenoceptor activation contributes to modulation of DRG neuronal activity in rats. On the basis of our findings, we discuss the possible mechanisms whereby sympathetically released norepinephrine modulates the abnormal activity of DRG neuronal cell bodies after nerve injury.

Influence of retinoic acid on the differentiation pathway of T cells in the thymus.

This study investigated the ability of retinoic acid (RA) to influence T cell differentiation. All-trans-RA had marked effects on T cell differentiation in murine fetal thymic organ cultures (FTOCs). The time course of the effect of all-trans-RA in FTOC of day 14 C57BL/6 embryos revealed a twofold increase in the frequency of CD4 single-positive (SP) cells and a high level of CD3-bearing cells (CD3high cells) at a later stage of T cell development. At an earlier stage, all-trans-RA induced a twofold increase in the frequency of CD4 SP cells, but significantly suppressed the upregulation of CD3 and TCR. Reverse transcription-PCR using RA receptor (RAR) subtype-specific primers showed that RAR alpha but not beta and gamma is expressed during T cell development in the thymus and that its expression was associated with the generation of CD4/CD8 double-positive (DP) cells. In FTOC of day 16 BALB/c embryos, the level of V beta 3high cells was greatly reduced (1.4% of the CD3high cells) in response to the mouse mammary tumor virus-6-encoded superantigen, but V beta 3-bearing cells were rescued from the deletion in the presence of all-trans-RA (5.6% of the CD3high cells). Further, the inhibitory effect of all-trans-RA on thymocyte deletion was observed when the deletion was induced by a low concentration of staphylococcal enterotoxin B in FTOC. Taken together, these data suggest that RA increases the frequency of mature and self-reactive T cells in the thymus, possibly by inhibiting the process of negative selection at the DP stage of T cell differentiation.

Input patterns and pathways from the six semicircular canals to motoneurons of neck muscles. II. The longissimus and semispinalis muscle groups.

To reveal patterns of input from the six semicircular canals to motoneurons of various neck muscles and their relationship to the mechanical actions of individual neck muscles, patterns of input to neck motoneurons of the longissimus and the semispinalis muscle groups were investigated in the upper cervical spinal cord of anesthetized cats. Intracellular potentials were recorded from motoneurons of the longissimus muscle group (obliquus capitis superior muscle, OCS; splenius muscle, SPL; longissimus muscle, LONG) and the semispinalis muscle group (biventer cervicis muscle, BIV; complexus muscle, COMP), and effects of separate electrical stimulation of the six ampullary nerves on them were analyzed in each preparation. Neck motoneurons usually received convergent inputs from all of the six ampullary nerves, and motoneurons that supplied a particular muscle had a homogeneous pattern of input from the six ampullary nerves. Two different patterns of input were identified for motoneurons of these two muscle groups; one pattern for motoneurons of the longissimus muscle group and the other pattern for motoneurons of the semispinalis muscle group. Motoneurons of the OCS, the SPL, and the LONG muscles received excitation from the three contralateral ampullary nerves and inhibition from the three ipsilateral ampullary nerves. BIV and COMP motoneurons received excitation from the bilateral anterior canal nerves (ACNs) and the contralateral canal nerve (LCN) and inhibition from the bilateral posterior canal nerves (PCNs) and the ipsilateral LCN. Latencies of postsynaptic potentials (PSPs) evoked by stimulation of each of the six ampullary nerves indicated that the earliest component of excitatory PSPs (EPSPs) and inhibitory PSPs (IPSPs) was disynaptic in these motoneurons. However, trisynaptic IPSPs were evoked by stimulation of the contralateral PCN in a considerable number of BIV and COMP motoneurons. In OCS, SPL, and LONG motoneurons, all of the excitation from the contralateral and all of the inhibition from the ipsilateral ampullary nerves were mediated through the ipsilateral medial longitudinal fascicle (MLF). In BIV and COMP motoneurons, disynaptic excitation from the contralateral ACN and LCN and disynaptic inhibition from the ipsilateral LCN and bilateral PCNs were mediated through the ipsilateral MLF, whereas disynaptic excitation from the ipsilateral ACN was mediated through the ipsilateral lateral vestibulospinal tract. The patterns of semicircular canal input to neck motoneurons of these two muscle groups are related closely to the mechanical actions of the individual neck muscles and the optimal stimulus to the semicircular canals such that the connections will tend to stabilize head positions in response to head perturbations.

Identification of murine T cells reactive with the bacterial superantigen Yersinia pseudotuberculosis-derived mitogen (YPM) and factors involved in YPM-induced toxicity in mice.

We previously reported that Yersinia pseudotuberculosis-derived mitogen (YPM) acts as a superantigen to human T cells. In this study, we assessed the superantigenicity and toxicity of YPM using murine experimental models. YPM activated T cells to produce interleukin-2 in a major histocompatibility complex class II molecule-dependent manner. The T-cell blasts induced by YPM expressed T-cell receptor (TCR) beta-chain variable region (Vbeta)7, Vbeta8.1, Vbeta8.2 and Vbeta8.3. The injection of YPM into mice pre-sensitized with D-galactosamine induced lethal shock. This shock was blocked by the injection of monoclonal antibodies (mAbs) to CD4, TCR Vbeta7 plus Vbeta8, tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma), but not by injection to CD8 or unrelated Vbeta. These results indicate that YPM-induced shock requires the presence of CD4+ T cells bearing TCR Vbeta7 and Vbeta8, and that endogenous TNF-alpha and IFN-gamma mediate the lethal effects.

Implantation of IL-2-containing osmotic pump prolongs the survival of superantigen-reactive T cells expanded in mice injected with bacterial superantigen.

In the present study we investigated the mechanism of deletion of superantigen (sAg)-reactive T cells expanded in sAg-injected mice. In staphylococcal enterotoxin A (SEA)-injected mice, IL-2 activity in serum peaked at 1 to 3 h and the expression of IL-2R alpha-chain (IL-2R alpha) on SEA-reactive (V beta 3+, or V beta 11+) T cells peaked at 6 to 12 h after the injection. Expansion of V beta 3+ or V beta 11+ T cells peaked at 2 days after the injection when most of these T cells were IL-2R alpha negative, and IL-2 activity was not detected at all in serum, suggesting the involvement of IL-2 deprivation in the deletion of expanded T cells. Implantation of an osmotic pump containing human rIL-2 (IL-2 pump) prolonged the expanded states of V beta 3+ or V beta 11+ T cells in SEA-injected C57BL/6 mice and of V beta 8+ T cells in SEB-injected MRL +/+ and Fas Ag-defective MRL-Ipr/Ipr mice. Adult thymectomy did not change at all the effect induced by implantation of IL-2 pump. DNA fragmentation was blocked substantially in mice co-treated with SEA and IL-2 pump. In addition, CD4+ T cell blasts, obtained by in vitro stimulation with rIL-2 of splenic CD4+ T cells from mice co-treated with SEA and IL-2 pump, produced substantial amounts of IL-2 upon restimulation with SEA. These results indicate that deprivation of IL-2 is deeply involved in the deletion of expanded sAg-reactive T cells and their anergy induction in sAg-injected mice.

Cerebellar and cerebral inputs to corticocortical and corticofugal neurons in areas 5 and 7 in the cat.

1. In the parietal cortex (Px, areas 5 and 7), the organization and characteristics of cerebellar and cerebral inputs and their effects on efferent neurons were investigated with the use of intracellular and extracellular recording techniques in the anesthetized cat. 2. Evoked field potential analysis revealed that two regions of the Px, the caudal bank of the ansate sulcus (Ans. S.) and the crown of the suprasylvian gyrus (Ssyl. G.), received converging input from the dentate and the interpositus nucleus. The cerebellar input to the caudal bank of the Ans. S. was relayed via the ventrolateral region of the ventroanterior-ventrolateral (VA-VL) complex of the thalamus, whereas the cerebellar input to the crown of the Ssyl. G. was relayed via the dorsomedial region of the VA-VL complex. 3. A total of 176 neurons was recorded intracellularly in the Px to examine inputs from the cerebellum. Of these, 72 neurons were corticocortical neurons projecting to the motor cortex (Mx), and 48 were corticofugal neurons to the pontine nucleus (PN). Intracellular staining with horseradish peroxidase revealed that the former corticocortical neurons were layer III pyramidal neurons and the latter corticofugal neurons were layer V pyramidal neurons. 4. Stimulation of the brachium conjunctivum (BC) produced di- or polysynaptic excitatory postsynaptic potentials (EPSPs) in corticocortical neurons projecting to the Mx and corticofugal neurons to the pontine nucleus in the Px. The characteristics of BC-evoked EPSPs were different between the bank of the Ans. S. and the crown of the Ssyl. G. In the bank of the Ans. S., the slope of the rising phase of the BC-evoked EPSPs was steeper, and their minimum latency was shorter by 0.8 ms than those in the crown of the Ssyl. G. These differences may reflect differences in the terminal distribution and conduction velocity of the thalamocortical fibers relaying cerebellar input to these two parietal areas. 5. Stimulation of the Mx produced mono- or disynaptic EPSPs in both corticocortical neurons projecting to the Mx and corticofugal neurons projecting to the pontine nucleus in the Px. For each neuron, effective sites for inducing EPSPs were distributed very widely and sometimes covered both areas 4 and 6. Extensive corticocortical projection from the Mx to the Px was confirmed by injection of an anterograde tracer into the Mx. 6. These data indicate that neurons in the Px receive inputs from both the cerebellum and the Mx and send outputs to the Mx and the cerebellum.(ABSTRACT TRUNCATED AT 400 WORDS)

The enantioselective metabolism of 4-isopropenyltoluene in rabbits.

4-Isopropenyltoluene (8) was administered orally to rabbits and the following four optically active metabolites, 2-(p-tolyl)propanoic acid (10), p-(1-carboxyethyl)benzoic acid (11), 2-hydroxy-2-(p-tolyl)propanoic acid (12), and 2-(p-tolyl)-1,2-propanediol (13) were isolated from urine in addition to an optically inactive metabolite, 4-isopropenylbenzoic acid (9). The enantiomeric ratios of the metabolites 10 and 11 were respectively R/S = 33:67 and 39:61 (S predominance), whereas those of the metabolites 12 and 13 possessing a tertiary hydroxyl group were R/S = 77:23 and 84:16 respectively (R predominance). The presumed metabolic pathways of 8 in rabbits leading to these metabolites are discussed.

Morphology of primary somatosensory cortical neurons receiving input from the tooth pulp.

1. To elucidate the morphological and electrophysiological characteristics of tooth pulp-driven neurons (TPNs) in the primary somatosensory cortex (SI), we injected neurobiotin into TPNs whose electrophysiological characteristics had been identified. 2. TPNs, responsive to electrical stimulation of the tooth pulp, were recorded intracellularly and injected from areas 3a and 3b of SI. A total of 58 TPNs in SI were successfully injected and reconstructed. Nineteen of these TPNs were located in area 3a and 39 in area 3b. Three area 3a TPNs were identified in lamina II, eight in lamina III, seven in lamina V, and one in lamina VI. Five 3b TPNs were identified in lamina II, 19 in lamina III, 7 in lamina IV, 7 in lamina V, and 1 in lamina VI. 3. Thalamic and tooth pulp latencies of lamina III and IV TPNs were shorter than those of lamina II and V TPNs. On the other hand, lingual and masseteric nerve latencies of TPNs were not consistent with thalamic and tooth pulp latencies. 4. Three of 19 area 3a TPNs and 7 of 39 area 3b TPNs were classified as pulp-specific TPNs, which received only tooth pulp input. Thirteen of 19 area 3a TPNs and 24 of 32 area 3b TPNs were classified as low-threshold mechanoreceptive TPNs, which responded to nonnoxious mechanical stimulation of the receptive field, and only 2 area 3b TPNs were classified as wide-dynamic range TPNs. Six of the area 3a TPNs and 14 of the area 3b TPNs responded to electrical stimulation of the lingual and/or masseteric nerves. Nociceptive-specific TPNs were not recorded in this study. 5. Lamina II TPNs in areas 3a and 3b had small somata, and those in area 3a had dendrites spreading into laminae I-II. Two TPNs in area 3a had axon collaterals extending into area 4. In contrast, area 3b TPNs in lamina II have dendrites spreading into laminae I-III. Their axons did not extend deeply into the subcortical regions, and the axon collaterals reached into area 3a. 6. Lamina III TPNs were classified according to their morphological characteristics as pyramidal or nonpyramidal stellate TPNs. Pyramidal lamina III TPNs had typical pyramidal somata, like those of lamina V pyramidal cells. Furthermore, those in areas 3a and 3b had dendrites with numerous spines spreading into laminae I-III, and some of the area 3a TPNs have axons with collaterals projecting into area 4. Lamina III area 3b TPNs had morphological properties similar to those in area 3a.(ABSTRACT TRUNCATED AT 400 WORDS)

Accessory cell ability of Langerhans cells for superantigen is resistant to ultraviolet-B light.

We examined the effects of ultraviolet-B (UVB) irradiation on the accessory cell ability of Langerhans cells (LC) to induce a T-cell response to a superantigen, staphylococcal enterotoxin B (SEB). The ability of LC-enriched epidermal cells (LC-EC) to evoke a T-cell response to SEB was retained at the doses of UVB (up to 40 mJ/cm2) that profoundly affected the antigen-presenting function of LC-EC for a hapten, trinitrophenyl (TNP), and a protein antigen, conalbumin. Thus, the LC accessory function for superantigens is more resistant to UVB irradiation than that for ordinary antigens. This UVB resistance is presumably due to no requirement of antigen processing for superantigens as chemically fixed or chloroquine-treated LC-EC still retained their ability to induce T-cell responses to SEB. Higher doses of UVB (more than 60 mJ/cm2) reduced the accessory cell ability of LC-EC for SEB up to 50% of control. The addition of monoclonal antibodies against adhesion molecules between LC and T cells to the culture resulted in a substantial suppression of the T-cell response to SEB induced by nonirradiated LC-EC, while the UVB-irradiated LC-EC-induced T-cell response was not significantly blocked with these monoclonal antibodies. This suggested that the reduction of LC ability for superantigen by high doses of UVB is at least partly due to the impairment of adhesion molecules on LC by UVB irradiation.

Superantigen-like properties of an antibody bispecific for MHC class II molecules and the V beta domain of the T cell antigen receptor.

A working model for the action of superantigens (SAg) is that they are simple proteins having binding sites for both MHC class II molecules and the V beta domain of the TCR. Binding of a SAg to both molecules cross-links the TCR, inducing a biologic response. In this study, we have tested this working model using a SAg mimic consisting of a hybrid Ab bispecific for the murine MHC class II molecule I-E and the V beta 8 domain of the murine TCR. The bispecific Ab activates V beta 8-bearing T cells only in the presence of I-E molecules on APC when tested in vitro. The effect of the bispecific Ab in vivo revealed both clonal deletion and a reduction in the responsiveness of V beta 8-bearing T cells. Thus, the results suggest that molecules distinct from SAg that can bind to both MHC class II molecules and the V beta domain of the TCR can mimic the biologic actions of a SAg.

Stimulator cell type influences the response of T cells to staphylococcal enterotoxins.

Responses to the superantigen Mls are characterized by proliferation of a significant percentage of T cells expressing receptors encoded by one or a few V beta gene segments. Apparently similar responses are elicited by the staphylococcal enterotoxins (SEs) and other bacterial superantigens. We have observed that T cells can be stimulated by the bacterial superantigen SEs presented by either spleen cells or fibroblasts transfected with the appropriate MHC class II genes. However, the results in this study showed that T cells required more than 100-fold higher concentrations of SEA in the presence of L cell transfectants than spleen APC, although T cell responses to SEB and several other toxins presented by the two types of APC were equivalent. Thus, L cell transfectants have a selective defect in presenting SEA. These data suggest that fibroblasts lack a component required by SEA to stimulate certain T cells, and lead us to propose an alternative model for bacterial superantigen mitogenesis in which the superantigen binds to and modifies the behavior of an endogenous co-ligand.