Systemic autoimmune disease induced by dendritic cells that have captured necrotic but not apoptotic cells in susceptible mouse strains

Systemic lupus erythematosus (SLE) is an autoimmune disorder of a largely unknown etiology. Anti-double-stranded (ds) DNA antibodies are a classic hallmark of the disease, although the mechanism underlying their induction remains unclear. We demonstrate here that, in both lupus-prone and normal mouse strains, strong anti-dsDNA antibody responses can be induced by dendritic cells (DC) that have ingested syngeneic necrotic (DC/nec), but not apoptotic (DC/apo), cells. Clinical manifestations of lupus were evident, however, only in susceptible mouse strains, which correlate with the ability of DC/nec to release IFN-gamma and to induce the pathogenic IgG2a anti-dsDNA antibodies. Injection of DC/nec not only accelerated disease progression in the MRL/MpJ-lpr/lpr lupus-prone mice but also induced a lupus-like disease in the MRL/MpJ-+/+ wild-type control strain. Immune complex deposition was readily detectable in the kidneys, and the mice developed proteinuria. Strikingly, female MRL/MpJ-+/+ mice that had received DC/nec, but not DC/apo, developed a 'butterfly' facial lesion resembling a cardinal feature of human SLE. Our study therefore demonstrates that DC/nec inducing a Th1 type of responses, which are otherwise tightly regulated in a normal immune system, may play a pivotal role in SLE pathogenesis.     

Characterization of hemagglutinin variant strains of adenovirus 15 and 9

Summary Five adenovirus 15/Hx and one Ad9/Hx strain with a common novel hemagglutinin were compared serologically and by DNA restriction analysis with six endonucleases with the related prototypes. The five Ad15/Hx strains represented five different genome types.With 1 FigureAided by grants from the Deutsche Forschungsgemeinschaft (Wi 2/21-1), Bundesministerium für Jugend, Familie und Gesundheit, and Förderverein der Deutschen Vereinigung zur Bekämpfung der Viruskrankheiten e. V., FRG.     

Protection of Chicken Embryos by Viridans Streptococci Against the Lethal Effect of Staphylococcus aureus

Chicken embryos were used to investigate the mechanism by which viridans streptococci inhibit the growth of pathogenic staphylococci. Ten-day-old embryonated eggs were infected allantoically. At a concentration of 1.8 x 10(2) colony-forming units (CFU) of viridans streptococci, the percentage of fatalities was less than 10%. There was 80% fatality with 8 x 10(1) CFU of Staphylococcus aureus strain 502A and 100% when a 100-fold increase in concentration was used. An inoculum size of 10(2) to 10(3) CFU of viridans streptococci was chosen to protect the embryos against the lethal effect of strain 502A when challenged 24 h later. The survival after challenging at 4 days was 93% in protected eggs and 37% in unprotected eggs. Chicken embryos receiving heat-killed viridans and challenged with strain 502A when examined after 4 days did not demonstrate a protective effect. This protection of embryonated eggs could not be transferred by administration of sterile filtrate of allantoic fluid in which protecting strain was grown. The experimental infection of embryonated eggs has demonstrated that prior allantoic infection with viridans streptococci affords significant protection against subsequent challenge with virulent staphylococci.     

Serum cytokine profiles associated with clinical presentation in Vietnamese infected with hepatitis B virus.

BACKGROUND/OBJECTIVES: An ineffective cytokine response is thought to be one of the reasons for the failure to suppress hepatitis B virus (HBV) replication and to eliminate the virus. We investigated the serum levels of interleukin (IL)-6, IL-10, IL-12, and interferon (IFN)-gamma in HBV-infected Vietnamese patients to determine whether they were related to the outcome of HBV infection. STUDY DESIGN: Samples from a total of 154 HBV-infected patients with well-characterised clinical profiles and 56 healthy controls were assessed. RESULTS: Serum IL-6 levels, which were inversely correlated with transaminase levels, were highest in patients with liver cirrhosis (LC) and hepatocellular carcinoma (HCC) and lowest in those with either asymptomatic (ASYM), acute or chronic HBV, and thus, represented the best marker of HBV-related clinical progression. Compared with the healthy control group, serum IL-12 was uniformly elevated in all HBV-infected patients apart from those with ASYM infections, implying no impairment of production of this cytokine in HBV-infected individuals. Serum IL-10 and IFN-gamma levels, however, were uniformly low and showed no association with clinical presentation. Cytokine profiles were not influenced by the presence of hepatitis B e antigen (HbeAg). CONCLUSIONS: Serum IL-6 and IL-12 but not IL-10 and IFN-gamma are associated with the clinical presentation in HBV-infected Vietnamese patients.     

Protective Cellular Immunity Against Influenza Virus Induced by Plasmid Inoculation of Newborn Mice

Neonate organisms display an intrinsic disability to mount effective immune responses to infectious agents or conventional vaccines. Whereas low. doses of antigens trigger a suboptimal response, higher doses are frequently associated with tolerance induction. We investigated the ability of a plasmid-expressing nucleoprotein of influenza virus to prime a specific cellular immune response when administered to newborn mice. We found that persistent exposure to antigen following plasmid inoculation of neonates leads to a vigorous priming of specific CTLs rather than tolerance induction. The CTLs were cross-reactive against multiple strains of type A influenza viruses and produced IFNγ but no IL-4. The immunity triggered by plasmid inoculation of neonates was protective in terms of pulmonary virus clearance as well as survival rate following lethal challenge with influenza virus. Whereas the persistence of the plasmid at the site of injection was readily demonstrable in adult mice at 3 months after inoculation, mice immunized as newborns displayed no plasmid at 3 months and very little at 1 month after injection. Thus, DNA-based immunization of neonates may prove an effective and safe vaccination strategy for induction of cellular immunity against microbes that cause serious infectious diseases in the early period of life.     

Sleep-related neurons in the central nucleus of the amygdala of rats and their modulation by the dorsal raphe nucleus

The amygdala (AMY) plays an important role in initiating appropriate neurobehavioral responses to emotionally arousing events. Its major efferents from the central nucleus (Ace) to the basal forebrain, hypothalamus and brainstem permit it to influence sleep mechanisms. To characterize further the neuronal activity of AMY during sleep and wakefulness, we recorded single neuronal activity in Ace across behavioral states in freely moving, normally behaving rats. Of the 49 neurons recorded from Ace, 24 neurons had firing patterns related to sleep-wakefulness (S-W). Of these, 50% (n = 12) had a high firing frequency during wakefulness (W) or both W and REM sleep (REM), 12% (n = 3) were non-REM (NREM)-related, 17% (n = 4) had a high firing rate in REM (REM-ON), and 20% (n = 5) fired at a low rate during REM. Because serotonin introduced into AMY during REM induces short-latency changes of state, we also studied the effects of low frequency (1 Hz) electrical stimulation of the dorsal raphe nucleus (DRN) on Ace neurons. All REM-ON neurons recorded from Ace were inhibited by DRN stimulation, and other cell types were unaffected. Thus, we found that the majority of cells in Ace related to S-W fired slowly during NREM and increased their discharge during W and/or REM, and that the DRN has the potential for modulating the spontaneous activity of REM-ON cells in rats.     

Functional interaction of auxiliary subunits and synaptic proteins with Ca(v)1.3 may impart hair cell Ca2+ current properties

We assessed the functional determinants of the properties of L-type Ca(2+) currents in hair cells by co-expressing the pore-forming Ca(V)1.3alpha(1) subunit with the auxiliary subunits beta(1A) and/or alpha(2delta). Because Ca(2+) channels in hair cells are poised to interact with synaptic proteins, we also co-expressed the Ca(V)1.3alpha(1) subunit with syntaxin, vesicle-associated membrane protein (VAMP), and synaptosome associated protein of 25 kDa (SNAP25). Expression of the Ca(V)1.3alpha(1) subunit in human embryonic kidney cells (HEK 293) produced a dihydropyridine (DHP)-sensitive Ca(2+) current (peak current density -2.0 +/- 0.2 pA/pF; n = 11). Co-expression with beta(1A) and alpha(2delta) subunits enhanced the magnitude of the current (peak current density: Ca(V)1.3alpha(1) + beta(1A) = -4.3 +/- 0.8 pA/pF, n = 10; Ca(V)1.3alpha(1) + beta(1A) + alpha(2delta) = -4.1 +/- 0.6 pA/pF, n = 9) and produced a leftward shift of approximately 9 mV in the voltage-dependent activation of the currents. Furthermore, co-expression of Ca(V)1.3alpha(1) with syntaxin/VAMP/SNAP resulted in at least a twofold increase in the peak current density (-4.7 +/- 0.2 pA/pF; n = 11) and reduced the extent of inactivation of the Ca(2+) currents. Botulinum toxin, an inhibitor of syntaxin, accelerated the inactivation profile of Ca(2+) currents in hair cells. Immunocytochemical data also indicated that the Ca(2+) channels and syntaxin are co-localized in hair cells, suggesting there is functional interaction of the Ca(V)1.3alpha(1) with auxiliary subunits and synaptic proteins, that may contribute to the distinct properties of the DHP-sensitive channels in hair cells.     

Retrograde tracing studies of subdivisions of the orbicularis oculi muscle in the rhesus monkey

Functionally and anatomically, the orbicularis oculi (OO) muscle can be subdivided in a pretarsal, a preseptal, and an orbital portion. In the rhesus monkey, fluorescent and neuronal retrograde tracing experiments were performed in the pretarsal or the orbital portion of the OO muscle, or both, using fast blue, diamidino yellow, and wheat germ agglutinin-horseradish peroxidase as tracers. The preseptal portion was not investigated because of close anatomical relationships to the other portions. It was found that motoneurons innervating the OO muscle are located exclusively within the intermediate subnucleus of the motor facial nucleus. The upper pretarsal motoneurons show a specific distribution in the dorso-rostral border area of the intermediate subnucleus, representing a dome-like organization, while lower pretarsal motoneurons are situated more ventrally in the adjacent area. The pretarsal motoneurons are all located dorsally in the rostral half and the upper part of the caudal half of the intermediate subnucleus. The upper pretarsal portion is subserved by about one third of the total intermediate motoneuron population. The size of the upper pretarsal motoneurons is similar to that of the motoneurons of the lower pretarsal portion of the OO muscle and falls, for the vast majority, into the large motoneuronal range. Motoneurons belonging to the upper and lower orbital portions are located ventrally and are more randomly distributed in the rostral half of the intermediate subnucleus. The size of orbital motoneurons varies from small to large. The large fraction of pretarsal motoneurons may reflect the specific function of the upper pretarsal portion during rapid and highly coordinated movements of the eyelids in different types of blinking. Received: 18 September 1997 / Accepted: 13 March 1998     

Sodium currents in mammalian muscle

1. A method is described which allows the approximate computation of membrane current from measurements with three electrodes in the mid-region of a muscle fibre.