In the latter case, the secretory mechanism involves

intr

In the latter case, the secretory mechanism involves

intragranular compartments organized as tubular vesicles or tubular networks, which bud from donor granules and relocate specific granule products in response to stimulation 24. Consequently, PMD would accomplish discharge of secretory constituents from storage granules without granule-to-granule and granule-to-plasma membrane fusion events and without direct granule opening to the cell exterior, as we have observed in our experiment. PMD has been demonstrated to occur in case of cytokine secretion 23, 24, but the molecular mechanisms underlying PMD are largely unknown. In particular, very little is known about what governs the cell decision to opt for either release of entire granules or PMD, and the precise molecular mechanisms that regulate mobilization of vesicle-associated secretory MK-2206 datasheet aliquots in a PMD manner. In light of these results, it can be speculated that the lowered availability of cytosolic Ca2+ in activated MCs interacting with Tregs could be responsible for unsuccessful exocytosis but could be enough for promoting PMD. This could explain the selective inhibitory effect of Tregs on the secretion of pre-stored and usually early released mediators and the delay of TNF-α release observed at early time point. In conclusion, this study describes the dynamic and functional profile

of MC–Treg interactions. This cross-talk is not restricted to BMMCs but is a common feature of mature MCs and human MCs. Importantly, AZD6738 in vitro Liothyronine Sodium we found that this cross-talk is regulated on a single-cell level also providing the first morphological evidence for a role of the OX40–OX40L axis in Treg inhibition of MC function. However, the dynamics of Treg–MC conjugates reflects a complex synaptic structure and a more detailed analysis is necessary to understand the molecular composition of this interaction. Moreover, the evidence of PMD in MCs interacting with Tregs underlines the necessity to understand all events and mechanisms governing differential sorting, packing and

secretion of granule-stored mediators. Our findings pave the road to identify selective secretory pathways that are still partially unknown and might regulate MC degranulation without modifying their innate immune functions. C57BL/6 mice were purchased from Harlan (Harlan Italy), C57BL/6 OX40-deficient mice were kindly provided by M. Colombo in Milan, Italy. CD4+CD25+ cells were purified using the CD25+ T cell isolation kit (Miltenyi Biotec, Bergisch Gladbach, Germany) according to the manufacturer’s instructions. By flow cytometry analysis, cells were more than 90% Foxp3+. BMMCs were obtained by in vitro differentiation of BM cells taken from mouse femur as described 4. After 5 wk, BMMCs were monitored for c-kit and FcεRI expression by flow cytometry. Purity was usually more than 97%.

In the recent year, timing for initiation of dialysis in advance

In the recent year, timing for initiation of dialysis in advance CKD patients has been discussed widely, and there is a trend of not to dialysis patient solely depends LDE225 research buy on the level of GFR or serum creatinine. If patients have no life-threatening condition or without major uremic symptom/sign, it is suggested dialysis could be delayed. In Taiwan, it has been a rule to initiate dialysis at a very low level of GFR, no matter due to Insurance regulation or patient’s willing. Our unique experience in dialysis initiation could provide more information for other countries. LIEW ADRIAN Department of Renal Medicine,

Tan Tock Seng Hospital, Singapore As a renal replacement therapy, renal transplantation confers the best survival advantage over dialysis for the patient with end-stage renal disease (ESRD)1. The transplantation of these patients prior to the initiation of dialysis therapy, known widely as preemptive renal transplantation, offers the advantage of avoiding the complications, morbidities, and infrastructure and manpower

costs associated with dialysis access and therapy. The further argument for preemptive transplantation stems AT9283 ic50 from the unfavorable death rates among waitlisted patients compared with transplant recipients2. Indeed, large analyses of registry data, albeit retrospective in nature, had demonstrated that preemptive renal transplantation leads to considerable improvements in allograft and patient survival2,3, when compared to transplantation after a period of dialysis therapy. In fact, with incremental time on dialysis, the risk of graft loss and patient death after transplantation had been shown to increase linearly4. While the exact reasons for these improved outcomes with preemptive renal transplantation had not been clear, several observations had been made that could provide some information towards the contributing factors. Delayed graft function and biopsy-confirmed acute Protein kinase N1 rejection are well known to have negative effects on graft survival, and the association of preemptive transplantation with

lower rates of these occurrences5 could contribute to its superior outcomes noted in these large analyses. The low solute clearances associated with dialysis therapy expose patients to risks of accelerated atherosclerosis, malnutrition and chronic inflammation, which are adverse outcomes that can be avoided with preemptive transplantation5. Preemptive transplant recipients have also been found to have socioeconomic and demographic features that predict better outcomes, namely younger age, higher educational background, economic viability and fewer HLA antigen mismatches3,6. Furthermore, it had also been implied that preemptive transplantation alone could have direct beneficial effects on graft survival. The precise timing to proceed with preemptive transplantation remains controversial.

[113] It was also observed that structure specificity of RAGs cou

[113] It was also observed that structure specificity of RAGs could be attributed to the sequence at the single-stranded region. Cytosines were the most preferred, followed by thymines while purines were not cleaved at all. A consensus sequence of ‘C(d)C(s)C(s)’

(d, double-stranded; s, single-stranded) was also proposed for the generation of breaks at single-strand/double-strand transitions.[114] The nonamer binding region of RAG1 was not selleck kinase inhibitor important for RAG cleavage at non-B DNA structures, in contrast to that at RSS.[115] The study showed low cleavage kinetics and a lack of cleavage complex formation at heteroduplex DNA, as the two mechanisms that ensured the control of the pathological activity of RAGs.[115] In an ideal scenario, RAGs target RSS within the immunoglobulin/TCR loci. However, a large number of RSS-like sequences (cryptic RSS) exist throughout the genome and this would lead to the non-specific targeting of RAGs leading to DNA double-strand breaks outside the immunoglobulin/TCR loci, resulting in genomic rearrangements. If the rearrangement Target Selective Inhibitor Library in vivo juxtaposes the immunoglobulin/TCR

regulatory sequences like promoters or enhancers to proto-oncogenes, it could lead to over-expression of the oncogenes culminating in lymphoid malignancies. RAGs are known to generate breaks at sequences resembling heptamer or nonamer because of misrecognition in several leukaemias and lymphomas, which include translocations like MTS1, LMO2, TTG-1, SIL and SCL.[116-119] The discovery that RAGs can detect and cleave non B-DNA structures further increased the spectrum of non-specific cleavage by RAGs.[110] In case of t(14;18) translocation at follicular lymphoma wherein nearly 75% of the breakpoints are dispersed over a 150-bp region called major breakpoint region of BCL2,[120] it has been shown that a non-B structure Gemcitabine cell line can form, which is specifically targeted and cleaved by RAGs.[110,

111] Later, the nature of this structure was identified as a G-quadruplex.[112, 121] It has also been shown that RAGs can cleave at an eight-nucleotide motif ‘CCACCTCT’ in the minor breakpoint cluster of the BCL2 in a nonamer-independent manner.[122] To generate a functional antibody or TCR, several of the genomic segments propagating in the embryo have to select each other, merge in various combinations and further modify themselves. Though the main players in the process have been identified, the mechanism by which each of the individual proteins acts and broadly how the chronological order is regulated are not known. The structure of RAG proteins still remains elusive. Several questions regarding the structure specificity of RAGs are unclear. Biochemical and biophysical studies on the domains within the core and non-core regions of these proteins, studies on the full length proteins in vivo, and detection of their interacting partners are being pursued.

rPWV may add detailed insights into early microvascular pathophys

rPWV may add detailed insights into early microvascular pathophysiology, potentially beyond microalbuminuria. “
“Twin infants tend to have LBW and microvascular alterations but do not appear to have an increase in cardiovascular mortality later Peptide 17 datasheet in life as singleton infants. We hypothesized that twin infants born to normotensive mothers would not have capillary rarefaction at birth. We studied 26 dizygotic

twin infants and compared them with 115 consecutive singleton infants to normotensive mothers. We used orthogonal polarized spectroscopy to measure basal (i.e., functional) and maximal (i.e., structural) skin capillary density according to a well-standardized protocol. Twin infants have significantly higher BCD (mean difference 4.3 capillaries/mm2, 95% CI: 0.4, 8.1, p = 0.03) and have marginally significantly higher MCD (mean difference 3.9 capillaries/mm2, 95% CI: −0.6, 8.3, p = 0.086) compared to singleton infants.

Birth weight was significantly associated with GSK126 mw BCD and MCD (p = 0.003 and 0.006). Twin infants with low and NBWs tend to have higher functional and structural capillary densities compared to singleton infants. Further longitudinal studies of skin capillary density and of retinal vascular parameters commencing from birth to various stages in early childhood are essential to identify the dynamics and the exact timing, if any, of the remodeling of microcirculation in these individuals. LBW is now considered an independent risk factor for adult cardiovascular C-X-C chemokine receptor type 7 (CXCR-7) disease as both clinical and epidemiological studies have shown an association with cardiovascular risk factors such as essential hypertension, dyslipidemia, diabetes mellitus, and insulin resistance in later life [7, 8]. Although the exact mechanism for this association is not as yet fully elucidated, several studies have suggested that microcirculatory abnormalities may be implicated [10, 15, 18, 25, 34]. LBW is known to be associated with several structural and functional microvascular abnormalities including

reduction in microvascular density or rarefaction [9, 11, 26, 34, 37]. Rarefaction of arterioles and capillaries is an early hallmark of essential hypertension [5, 30, 36] and we have previously shown that individuals with borderline intermittent essential hypertension, and normotensive individuals with familial predisposition to essential hypertension have significant capillary rarefaction [3, 4]. Twin infants are very interesting to study because as a group they tend to have LBW and significant microvascular alterations including narrower retinal arterioles [37] but do not appear to have an increase in cardiovascular mortality or morbidity later in life as singleton infants [13, 40].

Caspase-3 activity was determined by measuring proteolytic cleava

Caspase-3 activity was determined by measuring proteolytic cleavage of the fluorogenic caspase-3 substrate Ac-Asp-Glu-Val-Asp-AMC (Calbiochem, Laeufelfingen, Switzerland). Cells were incubated for 1 h at 37°C with 2·5 µM substrate. The cleaved reporter group fluorescence was measured at an excitation wavelength of 360 nm and an emission wavelength of 465 nm. To quantify possible ROS generation by fibroblasts, experiments were performed measuring the oxidation of non-fluorescent 2,7′-dichlorofluorescin (DCFH) (Sigma, Buchs, Switzerland) substrate to highly fluorescent DCF by ROS. Small molecule library As the experimental setup could be performed only for a short exposure, LA were incubated

for 5 h with fibroblasts. Cells were loaded with DCFH during a 60-min incubation in Hanks’ balanced salt solution (HBSS; Sigma, Buchs, Switzerland) supplemented with 30 mM glucose (D-(+)-glucose (Sigma), pH 7·4, and 50 µM DCFH-DA (Sigma) at room temperature in the dark. Cells were washed three times with HBSS to remove any extracellular probe from the extracellular environment. Thereafter, cells were

exposed to various concentrations of local anaesthetic in HBSS. The amount of generated DCF was measured using a fluorescence Synergy HT (Bio-TEK, Winooski, VT, USA). The excitation filter was set at 485 nm and the emission filter was set learn more at 530 nm. At the same time, cell viability and activity of caspase-3 were determined. Values were expressed as mean ± standard deviation (s.d.). Results are presented as a percentage of control. Cell count and ELISA data regarding viability, proliferation rate and caspase-3 activity were analysed using three-way analysis of variance (anova). Pearson’s product–moment correlation coefficients were computed between ELISA results regarding production of ROS and cell viability. OriginPro 8G (OriginLab, Northampton, MA,

USA) and spss (SPSS, Inc., Chicago, IL, USA) were used for statistical analyses. A probability of P < 0·05 was considered statistically significant. In group 1, no negative effect of lidocaine and ropivacaine regarding cell survival was observed for the 0·3 mg/ml concentration (Fig. 1a). In the Erlotinib concentration presence of bupivacaine, cell death ranged between 20% and 40%. With the 0·6 mg/ml concentration, cell survival in the lidocaine and ropivacaine group was similar with 50–90%, while a prominent effect on cell death rate was observed for bupivacaine, with 30% survival after 3 days, 5% after 6 days and no survival after 9 days of incubation (Fig. 1b). In group 2, with a permanent incubation of fibroblasts with LA at a concentration of 0·3 mg/ml, 20–30% dead cells were found with lidocaine and ropivacaine after an incubation between 3 and 9 days. Cell death was more evident in the bupivacaine group, showing a time-dependent decrease of survival (Fig. 1c).

6b) The inhibition of PI3K and JAKs reduced, but did not abolish

6b). The inhibition of PI3K and JAKs reduced, but did not abolish, the enhanced MCP-1 secretion, which was induced after monocytes were treated with PAR2-cAP together with IFN-γ (Fig. 5a). This reduced level of secreted MCP-1 was similar to the level reached after monocytes were stimulated with PAR2-cAP alone (Fig. 5a,b). These data indicate that PAR2-cAP effects on MCP-1 secretion by human monocytes are mediated not only via a signalling Selleckchem Everolimus pathway involving PI3K activation, but also via another

pathway (Fig. 6b). Surprisingly, the PKCδ inhibitor rottlerin enhanced the effect of PAR2-cAP and IFN-γ on MCP-1 release by monocytes (Fig. 5a). Rottlerin also synergized with PAR2-cAP in its action on MCP-1 secretion (Fig. 5b). Moreover, rottlerin, when applied alone, enhanced MCP-1 secretion by human monocytes (Fig. 5c). Treatment with the p38

inhibitor SB203580 did not influence the increased MCP-1 secretion caused by either PAR2-cAP stimulation or combined application of PAR2-cAP and IFN-γ (Fig. 5a,b). The levels of secreted MCP-1 after IFN-γ stimulation were below the threshold in the neutrophil samples and could therefore not be determined (Fig. 3a,b). The treatment of human monocytes with IFN-γ yielded no significant changes in MCP-1 levels (Fig. 3c). Hence, the effects of the inhibitors of signalling molecules at MCP-1 release were not studied after IFN-γ stimulation of human monocytes and neutrophils. Altogether, the results of our experiments allowed us to suggest a possible scheme of signalling events involved in the enhancement of MCP-1 secretion triggered after combined stimulation of human neutrophils and monocytes EPZ015666 molecular weight with PAR2-cAP and IFN-γ (Fig. 6a,b). In summary, our study demonstrates that PAR2 agonist acting alone can enhance a bactericidal response of human neutrophils from and monocytes in vitro. However, PAR2 agonist is unable to synergize with IFN-γ in the enhancement of the bactericidal response. On the other hand, PAR2 agonist and IFN-γ do synergize to increase MCP-1 secretion by human neutrophils and monocytes during the late phase (after 24 hr)

of the inflammatory response. This synergistic action of PAR2 agonist and IFN-γ on MCP-1 release apparently involves the activation of PI3 kinase and JAKs in neutrophils and monocytes. The work was supported by grants from the IZKF Münster (Stei3/034/09), German Research Foundation (SFB 293-A14, STE 1014/2-2), CERIES (Paris), Weston Haven foundation San Francisco USA (to M.S.), SFB 293 (S.L.), IMF grant SH 120709 (University of Münster, Germany) (to V.M.S.), IMF grant FE 110905 (University of Münster, Germany) (to M.F.) as well as Canadian Institutes of Health Research (Operating and Proteinases and Inflammation Network grants to M.D.H.), Transregional Collaborative Research Centre 34 (C12) (to D.H. and J.R.) and IMF grant HO 220912 (University of Münster, Germany) (to D.H.). The position of V.M.

Four

days after admission, Mr MF’s cardiologist transferr

Four

days after admission, Mr MF’s cardiologist transferred him to CCU to optimize his cardiac management. Mr MF informed the renal team that he wished to stop dialysis and his wife agreed, stating R788 mouse that her husband had discussed this during his last brief time at home. The renal team doubted Mr MF had the capacity for decision making and asked a psychiatrist to give a second opinion. The cardiologist was uncomfortable with the patient’s decision and asked Mr MF to continue dialysis until the anti-depressants became effective. Mr MF requested his decision be respected. Mr MF’s wife accused the cardiologist of bullying her husband into ongoing dialysis. The cardiologist noted a potential conflict of interest because Mr MF’s wife had previously divulged to him that Mr MF was physically and verbally abusive towards her. Mr MF’s family articulated distress at a family meeting with the renal and cardiac teams that his wishes were not being respected and he was being forced to dialyse. All agreed to await the outcome of the second opinion of Mr MF’s capacity to make decisions about end of life. Mr MF was not present at the family meeting. Mr MF

was deemed capable of EOL decisions by a consultant psychiatrist. The three medical teams – renal, cardiology and psychiatry – met with the hospital solicitor because the cardiologist was uncomfortable with the decision to withdraw dialysis. The meeting reached a consensus of EOL care without dialysis and the renal team spoke to the patient about cessation of dialysis. Mr MF was referred to the consultative palliative care team and was Metformin subsequently transferred from CCU to the Renal Ward. The cardiologist remained distressed and asked the patient and

his wife to sign acknowledgement of refusal of medical treatment. The renal inpatient team and palliative care consulting team initiated the care of the dying pathway and Mr MF died peacefully shortly after with his family in attendance. The family sent a letter to the renal team a week later thanking them for caring for Mr MF. This complicated medical case was compounded by distress in the Florfenicol healthcare team. Members of the team disagreed about treatment plans and the boundaries of the patient’s autonomy. The distress could not be resolved despite wide consultation with colleagues and legal involvement. This case demonstrates a number of problems frequently encountered by nephrologists Advance discussions with nephrologists prior to procedures.  This patient would have benefited by seeing a nephrologist before the renal artery angioplasty was attempted, allowing discussions of likely outcome and complications. The history suggests that the procedure was being attempted to reduce episodes of APO. This patient was known to have cardiac disease with ongoing angina and a blocked coronary stent. He therefore has potential mechanisms for pulmonary oedema unrelated to his renal arteries and thus raises the question of whether this procedure could be effective.

The pattern of coordinated behaviors that we observed provides in

The pattern of coordinated behaviors that we observed provides insight into infants’ perceptual understanding of real 3D objects in the world. The infant’s visual system extracts geometric information contained in 2D images in an attempt to analyze the projected 3D

configuration, and this perceptual information serves to guide both oculomotor and manual action systems. Our findings www.selleckchem.com/products/gsk1120212-jtp-74057.html provide important insights into the development of mechanisms for processing pictorial depth cues and extracting information about global 3D structure from pictures of objects. We thank Karen Adolph, Barry Cohen, Carl Granrud, Lisa Oakes, Paul Quinn, and Albert Yonas for helpful comments on this research. We also thank Lauren Clepper and Melissa Rozon for their assistance with scheduling and testing infants, and Lauren Kosinski for assistance with reliability coding. We are grateful for the contributions of all the parents and infants who participated in the research. This work was supported in part by the PSC-CUNY-40 and the George N. Shuster Fellowship to Sarah Shuwairi and by NIH grants R01-HD40432 and R01-HD48733 to Scott Johnson. “
“Three-dimensional (3D) object completion, the ability to MAPK Inhibitor Library perceive the backs of objects seen from a single viewpoint, emerges at around 6 months of age. Yet, only relatively simple 3D objects have been used in assessing its development.

This study examined infants’ 3D object completion when presented with more complex stimuli. Infants (N = 48) were habituated to an “L”-shaped object shown from a Avelestat (AZD9668) limited viewpoint; then they were tested with volumetrically complete (solid) and incomplete (hollow) versions of the object. Four-month-olds and 6-month-old girls had no preference for either display. Six-month-old boys and both sexes at 9.5 months of age showed a novelty preference for the incomplete object. A control group (N = 48), only shown the test displays, had no spontaneous preference. Perceptual completion of complex 3D objects requires infants to integrate multiple, local object features and thus may tax their nascent attentional skills. Infants might use mental

rotation to supplement performance, giving an advantage to young boys. Examining the development of perceptual completion of more complex 3D objects reveals distinct mechanisms for the acquisition and refinement of 3D object completion in infancy. “
“Adults typically use an exaggerated, distinctive speaking style when addressing infants. However, the effects of infant-directed (ID) speech on infants’ learning are not yet well understood. This research investigates how ID speech affects how infants perform a key function in language acquisition, associating the sounds of words with their meanings. Seventeen-month-old infants were presented with two label-object pairs in a habituation-based word learning task. In Experiment 1, the labels were produced in adult-directed (AD) speech.

Briefly, the inflamed ear was divided into dorsal and

Briefly, the inflamed ear was divided into dorsal and Selleck Wnt inhibitor ventral halves. Using a scalpel,

the dermis was separated from epidermis and both parts were incubated subsequently with 2000 U/ml collagenase (Sigma) and 2000 U/ml DNAse (Roche, San Diego, CA, USA) for 60 min. Next, ear tissue was passed through a 70-μm cell strainer before cells were washed and resuspended in PBS (w/o Mg2+ and Ca2+; Gibco/Invitrogen). The cell suspensions were blocked with anti-CD32/CD16 (Fc block; BD Biosciences, San Jose, CA, USA) for 10 min and stained with the following anti-mouse monoclonal antibodies (mAb): CD45-eFluor605 (eBioscience, San Diego, CA, USA), T cell receptor (TCR)-β-phycoerythrin (PE)-cyanin-7 (Cy7) (Biolegend, San Diego, CA, USA), CD4-APC (BD Biosciences), CD8-fluorescein isothicyanate

(FITC) (Santa-Cruz Laboratories, Santa Cruz, CA, USA), CD19-Q655 (Invitrogen), CD44-Pacific Blue (eBioscience), CD62L-Alexa-Fluor-700 (Biolegend), CD69-peridinin chlorophyll protein (PerCP)-Cy5·5 (BDBiosciences) and NKG2D-PE (eBioscience) for 30 min. Flow cytometric analysis of samples was analysed on a BD LSRII flow cytometer equipped with a blue, red and violet laser and data JNK inhibitor ic50 were analysed in BD FACS Diva software version 6·1.3. Ears were removed 24 and 48 h after challenge and a punch biopsy of 8 mm in diameter was collected from each ear, weighted and placed in 1 ml buffer [0·9% saline with 0·01% Triton X-100 (Sigma) + 1 protease inhibitor cocktail tablet (complete ethylenediamine tetraacetic acid-free from Roche)] on ice. The biopsies were subsequently homogenized and centrifuged at 4°C, 10 000 g for 15 min. The supernatants were centrifuged once more before being frozen at −80 degrees until use. Supernatants were analysed with Milliplex Map mouse cytokine/chemokine panel (Millipore, Billerica, MA, USA) using the Luminex detection method. Supernatants were analysed for the following cytokines and chemokines: IL-4, interferon gamma-induced protein of (IP)-10, IL-12 (p40), macrophage

inflammatory protein-2 (MIP-2), tumour necrosis factor (TNF)-α, interferon (IFN)-γ, IL-1β, IL-10 and IL-6. Serum samples taken 24 and 48 h after challenge were analysed for serum amyloid P (SAP) and haptoglobin using ELISAs according to the manufacturer’s recommendations (Genway, San Diego, CA, USA). Where indicated, donor mice were treated with 25 mg/kg CTLA-4-Ig 1 day prior to sensitization and sensitized subsequently with DNFB on day 0 according to standard procedure. Five days later the donor mice were killed and the inguinal lymph node was isolated. Single cell suspension was prepared by transferring the lymph node through a 70-μm cell strainer and washing cells with 1 × PBS (w/o Mg2+ and Ca2+, Gibco/Invitrogen). Lymph node cells from each group, respectively, were pooled and resuspended in 1 × PBS. Subsequently, cells were injected intravenously (i.v.

While four other surface lipoproteins encoded on various cp32 pla

While four other surface lipoproteins encoded on various cp32 plasmids (i.e. ErpG, ErpL, ErpX, and ErpY) have been shown to bind FH/FHL-1 from other animal sources, such as cattle, cat,

or dog (Stevenson et al., 2002), it is not clear what, if any, role this may play in the enzootic cycle of B. burgdorferi. In addition to the lipoproteins discussed in the preceding sections, there have also been several lipoproteins identified on the surface of B. burgdorferi that currently have no known function. Many of these were identified by Carroll and co-workers (i.e. lipoproteins Peptide 17 BBA65, BBA66, BBA71, and BBA73; Hughes et al., 2008) and through an examination of genes regulated by environmental cues through global expression profile analyses by Brooks et al. (Brooks et al., 2006; BBA689, BBA36, BBA66, BBA69, and BBI42). Given their cellular location on the surface, these lipoproteins likely perform an important role in either the tick or mammalian host environment, but future studies are needed to fully elucidate their functional role(s)

in B. burgdorferi virulence and/or Lyme disease pathogenesis. In addition to the numerous outer surface lipoproteins described previously, B. burgdorferi also contains integral OMPs that have transmembrane-spanning domains. OMPs are structurally different GSK126 molecular weight than lipoproteins in that they do not contain N-terminal lipid anchors. Bacterial OMPs, in general, provide an array of important functions, such as nutrient acquisition

(e.g. porins), antibiotic resistance (e.g. drug efflux pumps), protein transport and assembly, and cellular adhesion (Koebnik et al., 2000; Schulz, 2002; Bos et al., 2007). Likewise, B. burgdorferi OMPs also provide critical physiological functions for the spirochete cell, which is in accordance with the observation that nearly all known C-X-C chemokine receptor type 7 (CXCR-7) B. burgdorferi OMPs are encoded from stable chromosomal loci (Fraser et al., 1997). Interestingly, freeze-fracture electron microscopy has demonstrated that B. burgdorferi possesses a characteristically low abundance of integral OMPs, approximately 10-fold fewer than that detected in the Escherichia coli OM (Lugtenberg & van Alphen, 1983; Radolf et al., 1994). This paucity of integral membrane-spanning surface proteins, combined with the apparent limited antigenicity of OMPs, has seriously hindered identification of B. burgdorferi OMPs. As a result, relatively few nonlipoprotein surface proteins have been identified in B. burgdorferi, and even fewer have been fully characterized at the functional level. P66, encoded by ORF bb0603, was first identified as a 66-kDa chromosomally encoded B. burgdorferi antigen (Barbour et al., 1984; Coleman & Benach, 1987) with an immunogenic surface-exposed loop region (Bunikis et al., 1995, 1996; Probert et al., 1995).