Immune responses of a meningococcal A + W outer membrane vesicle (OMV) vaccine with and without aluminium hydroxide adjuvant in two different mouse strains

Meningococci (Neisseria meningiditis) of serogroups A and W have caused large epidemics of meningitis in sub‐Saharan Africa for decades, and affordable and multivalent vaccines, effective in all age groups, are needed. A bivalent serogroup A and W (A + W) meningococcal vaccine candidate consisting of deoxycholate‐extracted outer membrane vesicles (OMV) from representative African disease isolates was previously found to be highly immunogenic in outbred mice when formulated with the adjuvant aluminium hydroxide (AH). OMV has been shown to have inherent adjuvant properties. In order to study the importance of AH and genetical differences between mice strains on immune responses, we compared the immunogenicity of the A + W OMV vaccine when formulated with or without AH in inbred C57BL/6J and BALB/cJ mice (Th1 and Th2 dominant strains, respectively). The immunogenicity of the vaccine was found to be comparable in the two mice strains despite their different immune profiles. Adsorption to AH increased anti‐OMV IgG levels and serum bactericidal activity (SBA). The immune responses were increased by each dose for the adsorbed vaccine, but the third dose did not significantly improve the immunogenicity further. Thus, a vaccine formulation with the A and W OMV will likely benefit from including AH as adjuvant.     

The lipid raft microdomain-associated protein reggie-1/flotillin-2 is expressed in human B cells and localized at the plasma membrane and centrosome in PBMCs

Reggie-1/flotillin-2 is a plasma membrane-associated cytoplasmic protein, which defines non-caveolar raft microdomains. Reggie-1/flotillin-2 is enriched in detergent insoluble (TX100) membrane fractions (DIG), co-localizes with activated GPI-linked proteins and the fyn-kinase in neurons and T cells, and thus apparently participates in the assembly of protein complexes essential for signal transduction. In T cells activated by crosslinking the GPI-linked protein Thy-1 or by crosslinking the ganglioside GM1, reggie-1/flotillin-2 co-localizes with the T cell receptor. To determine whether reggie-1/flotillin-2 is also expressed in B cells, primary B cells from human blood and cell lines representing the developmental stages of pro, pre, mature and plasma B cells were analyzed by Western blotting, RT-PCR and immunofluorescence. Here, we show that reggie-1/flotillin-2 is expressed throughout B cell development, as well as in primary B cells, purified by cell sorting. On non-activated mature B cell Raji cell line we found reggie-1/flotillin-2 are exclusively in the detergent (TX100) insoluble membrane fractions that are staining positive for the raft marker GM1. Immunofluorescence microscopy showed that reggie-1/flotillin-2 is localized at the plasma membrane and marks intracellular spots in PBMCs. Confocal co-localization studies showed that reggie-1/flotillin-2 is associated with the plasma membrane, and the centrosomes (microtubule organizing centers) in these PBMCs. Comparison of reggie-1/flotillin-2 cDNA sequences with the genomic sequence database allowed us to determine the exon/intron structures in mouse and human. The gene organizations are highly conserved suggesting an important function of reggie-1/flotillin-2. Since reggie/flotillin proteins co-cluster with the T cell receptor and fyn kinases upon T cell stimulation, our findings of reggie-1/flotillin-2 in B cells suggest a similar role in B cell function.     

Differential inhibition of nicotine- and acetylcholine-evoked currents through alpha4beta2 neuronal nicotinic receptors by tobacco cembranoids in Xenopus oocytes

In tobacco, there are two types of compounds that interact with neuronal nicotinic acetylcholine receptors (nnAChRs) in the brain. The first is the addictive component of tobacco and an agonist of these receptors, nicotine. The second are cyclic diterpenoids called cembranoids that non-competitively inhibit many types of nnAChRs. Nictotinic receptors composed of alpha4beta2 subunits are the predominant type of nicotinic receptors in the brain. These alpha4beta2 receptors are up-regulated upon chronic exposure to nicotine and have been implicated in nicotine addiction. The present study was designed to determine whether the inhibitory effects of two cembranoids from tobacco [(1S, 2E, 4R, 6R, 7E, 11E)-2,7,11-cembratriene-4,6-diol (4R) and its diastereoisomer (1S, 2E, 4S, 6R, 7E, 11E)-2,7,11-cembratriene-4,6-diol (4S)] were comparable on acetylcholine (ACh) and nicotine-evoked currents through alpha4beta2 nnAChRs. alpha4beta2 nnAChRs from rat brain were expressed in Xenopus oocytes and studied using the two-electrode voltage-clamp technique. The dose-response curves for acetylcholine and nicotine were hyperbolic and bell-shaped, respectively. Although there was no difference in the potency between cembranoids 4R and 4S, both of these cembranoids more potently inhibited nicotine-induced currents than acetylcholine-induced currents. Furthermore, both cembranoids were more potent inhibitors of this receptor when they were preincubated for 1 min prior to application of agonist. The finding that cembranoids preferentially inhibit nicotine-induced currents over those elicited by the natural neurotransmitter acetylcholine may have important implications when developing strategies to prevent nicotine addiction and tobacco use.     

Cortical binocularity in convergent strabismus after section of the optic chiasm

In convergent strabismus (esotropia) the spatial asynchrony of the two eye inputs unbalances the interocular interactions, leading to the functional advantage of the nondeviated eye and the inhibition of the esotropic eye. It may be argued that the strabismic suppression, if it is the effect of inhibitory interactions between the eyes, could be removed by interrupting the interocular pathways at the optic chiasm. After chiasmatic section, each eye is connected only to the ipsilateral cortex through the uncrossed retinal projections and so the functionality of each eye's input is no longer interfered with by interocular mechanisms. In strabismic cats submitted, as adults, to section of the optic chiasm, we performed electrophysiological recordings from the striate cortex. Results show that in these animals: (1) the cortical responsiveness to the strabismic eye is strikingly higher than in esotropes with an intact optic chiasm; (2) the effectiveness of stimulation of the deviated eye is not different from that of the nondeviated eye in driving neurons of corresponding cortex; (3) surprisingly, a high degree of binocular activation is present in the cortex ipsilateral to the deviated eye, while in the cortex connected to the nondeviated eye the greatest majority of neurons are monocularly driven. Cortical binocularity depends on the corpus callosum, which conveys the input from the nondeviated eye to the opposite cortex (which receives the direct strabismic input), but not vice versa. The asymmetry of callosal transmission parallels the morphological asymmetry of callosal connections that occur in convergent strabismus. All together the findings indicate that the impaired effectiveness of esotropic input does not result from developmental deficit of the strabismic afferents but, rather, from inhibitory influences that are actively exerted through the interocular pathways. Strabismic suppression may be accomplished by the same interocular mechanisms underlying binocular rivalry.     

emm Gene distribution among erythromycin-resistant and -susceptible Italian isolates of Streptococcus pyogenes

The phenotypes and genetic determinants for macrolide resistance were determined for 167 erythromycin-resistant Streptococcus pyogenes strains. A cMLS phenotype was shown in 18% of the erythromycin-resistant strains, while inducible resistance was apparent in 31% and the M phenotype was apparent in 50%. The emm gene type of this set of resistant isolates and that of 48 erythromycin-sensitive isolates were determined. emm2 and emm48 were recorded only in the resistant strains of the M phenotype, while approximately all of the strains harboring the emm22 gene had the cMLS phenotype. More than 80% of the emm89-positive strains had the iMLS phenotype, and the same portion of emm4 strains presented the M phenotype. emm3 is recorded only among sensitive strains. The distribution of frequencies of the genetic determinant for the virulence factor M protein was significantly different both among organisms of different types of resistance and between resistant and sensitive populations of S. pyogenes under study.     

Intravenous mouse infection model for studying the pathology of Enterococcus faecalis infections

An intravenous mouse infection model was used to compare the virulence of Enterococcus faecalis strains, to study bacterial localization and organ histopathology, and to examine the effects of Nramp1 and gamma interferon (IFN-gamma) on the course of infection. Infection of BALB/c mice with 5 x 10(8) CFU of E. faecalis JH2-2, MGH-2, 418, DS16C2, or OG1X revealed the following virulence ranking (from highest to lowest): MGH-2, 418, DS16C2, JH2-2, and OG1X. Discernible differences in the number of MGH-2 and JH2-2 bacteria were observed at 7 days (168 h) in the blood (P = 0.037), at 72 h in the liver (P = 0.002), and at 8 h in the spleen (P = 0.036). At these time points, the number of MGH-2 bacteria was higher in the blood and liver while the number of JH2-2 bacteria was higher in the spleen. At 72 h, livers from MGH-2-infected mice had higher numbers of coalescing aggregates of leukocytes and a greater degree of caseous necrosis than those from JH2-2-infected mice. These results indicate a correlation between the virulence of the E. faecalis strain, the number of bacteria in the liver, and the degree of histopathology of the liver at 72 h postinfection. IFN-gamma was important in E. faecalis infection, since IFN-gamma gene knockout mice had reduced mortality and massive coagulative necrosis was observed in wild-type mice. The contribution of Nramp1 was unclear, since Nramp1(-/-) mice and the respective control mice were innately resistant to E. faecalis. The mortality of mice in this model is probably due to induction of cytokine release and massive coagulative necrosis.     

Genome-wide patterns of identity-by-descent sharing in the French Canadian founder population

In genetics the ability to accurately describe the familial relationships among a group of individuals can be very useful. Recent statistical tools succeeded in assessing the degree of relatedness up to 6–7 generations with good power using dense genome-wide single-nucleotide polymorphism data to estimate the extent of identity-by-descent (IBD) sharing. It is therefore important to describe genome-wide patterns of IBD sharing for more remote and complex relatedness between individuals, such as that observed in a founder population like Quebec, Canada. Taking advantage of the extended genealogical records of the French Canadian founder population, we first compared different tools to identify regions of IBD in order to best describe genome-wide IBD sharing and its correlation with genealogical characteristics. Results showed that the extent of IBD sharing identified with FastIBD correlates best with relatedness measured using genealogical data. Total length of IBD sharing explained 85% of the genealogical kinship''s variance. In addition, we observed significantly higher sharing in pairs of individuals with at least one inbred ancestor compared with those without any. Furthermore, patterns of IBD sharing and average sharing were different across regional populations, consistent with the settlement history of Quebec. Our results suggest that, as expected, the complex relatedness present in founder populations is reflected in patterns of IBD sharing. Using these patterns, it is thus possible to gain insight on the types of distant relationships in a sample from a founder population like Quebec.     

Bone Modeling Patterns and Morphometric Craniofacial Variation in Individuals From Two Prehistoric Human Populations From Argentina

Native human populations from South America display high levels of craniofacial variation encompassing gracile and robust skulls. Nevertheless, the processes of bone modeling by which morphological variation among populations were attained, remain poorly understood. Here we analyze the relationship between patterns of bone formation and resorption and morphometric variation in the upper face of adults belonging to farmers and hunter‐gatherers from northwestern and south Argentina. Our analyses reveal a common pattern of bone modeling of the malar bone characterized by the presence of formation areas. Thus, the larger size and greater development of malar bone exhibited by hunter‐gatherers would be linked to a greater magnitude of bone formation activity. Conversely, the glabella and the superciliary arch presented both formation and resorption areas with a variable distribution among individuals. In the extreme corresponding to more robust morphologies, the great development of the glabella is related to the presence of large formation fields, both in the upper region and toward the frontonasal suture. The less robust morphologies show resorption fields at the upper margin of the glabella, which would contribute to the weaker development of this region. The superciliary arch showed a complex relationship between its morphometric and histological variation; the individuals located at both extremes of the shape space presented large resorption areas located on its upper margin. Overall, our results show the existence of intraspecific variation in the patterns of bone modeling in the human upper face. Anat Rec, 297:1829–1838, 2014. © 2014 Wiley Periodicals, Inc.     

MLPA analysis in 30 Sotos syndrome patients revealed one total NSD1 deletion and two partial deletions not previously reported

Sotos syndrome (MIM #117550) is an autosomal dominant condition characterized by pre and postnatal overgrowth, macrocephaly and typical facial gestalt with frontal bossing, hypertelorism, antimongoloid slant of the palpebral fissures, prominent jaw and high and narrow palate. This syndrome is also frequently associated with brain, cardiovascular, and urinary anomalies and is occasionally accompanied by malignant lesions such as Wilms tumour and hepatocarcinoma. The syndrome is known to be caused by mutations or deletions of the NSD1 gene.To detect both 5q35 microdeletions and partial NSD1 gene deletions we screened 30 Brazilian patients with clinical diagnosis of Sotos syndrome by multiplex ligation dependent probe amplification.We identified one patient with a total deletion of NSD1 and neighbouring FGFR4, other with missing NSD1 exons 13-14 and another with a deletion involving FGFR4 and spanning up to NSD1 exon 17. All deletions were de novo. The two NSD1 partial deletions have not been previously reported.The clinical features of the three patients included a typical facial gestalt with frontal bossing, prominent jaw and high anterior hairline; macrocephaly, dolichocephaly, large hands; neonatal hypotonia and jaundice. All presented normal growth at birth but postnatal overgrowth. Two patients with NSD1 and FGFR4 gene deletions presented congenital heart anomalies.