Intranasal administration of unadjuvanted SARS-CoV-2 spike antigen boosts antigen-specific immune responses induced by parenteral protein subunit vaccine prime in mice and hamsters

With the continued transmission of SARS-CoV-2 across widely vaccinated populations, it remains important to develop new vaccines and vaccination strategies capable of providing protective immunity and limiting the spread of disease. Heterologous prime-boost vaccination based on the selection of different vaccine formulations and administration routes for priming and booster doses presents a promising strategy for inducing broader immune responses in key systemic and respiratory mucosal compartments. Intranasal vaccination can induce mucosal immune responses at the site of SARS-CoV-2 infection; however, the lack of clinically approved mucosal adjuvants makes it difficult to induce robust immune responses with protein subunit vaccines. Herein, we evaluated the immunogenicity of heterologous prime-boost regimens in mice and hamsters based on a parenteral vaccination of the antigen in combination with sulfated lactosylarchaeol (SLA) archaeosomes, a liposome adjuvant comprised of a single semisynthetic archaeal lipid, followed by an intranasally administered unadjuvanted SARS-CoV-2 spike antigen. Intranasal administration of unadjuvanted spike to mice and hamsters increased serum spike-specific IgG titers and spike-neutralizing activity compared with nonboosted animals. Spike-specific IgA responses were also detected in the bronchoalveolar lavage fluid in the lungs of mice that received an intranasal boost. In hamsters, the intranasal boost showed high efficacy against SARS-CoV-2 infection by protecting from body weight loss and reducing viral titers in the lungs and nasal turbinate. Overall, our heterologous intramuscular prime-intranasal boost with SLA-adjuvanted and unadjuvanted spike, respectively, demonstrated the potential of protein subunit formulations to promote antigen-specific systemic and mucosal immune responses.

Production, purification and immunogenicity of Gag virus-like particles carrying SARS-CoV-2 components

The virus-like particle (VLP) platform is a robust inducer of humoral and cellular immune responses; hence, it has been used in vaccine development for several infectious diseases. In the current work, VLPs carrying SARS-CoV-2 Spike (S) protein (Wuhan strain) with an HIV-1 Gag core were produced using suspension HEK 293SF-3F6 cells by transient transfection. The Gag was fused with green fluorescent protein (GFP) for rapid quantification of the VLPs. Five different versions of Gag-Spike VLPs (Gag-S-VLPs) consisting of Gag-S alone or combined with other SARS-CoV-2 components, namely Gag-S-Nucleocapsid (N), Gag-S-Matrix (M), Gag-S-Envelope (E), Gag-S-MEN, along with Gag alone were produced and processed by clarification, nuclease treatment, concentration by tangential flow filtration (TFF) and diafiltration. A pilot mouse study was performed to evaluate the immunogenicity of the Gag-S-VLPs through the measurement of the humoral and/or cellular responses against all the mentioned SARS-CoV-2 components. Antibody response to Spike was observed in all variants. The highest number of Spike-specific IFN-γ + T cells was detected with Gag-S-VLPs. No induction of antigen-specific cellular responses to M, N or E proteins were detected with any of the Gag-S, M, E/or N VLPs tested. Therefore, the Gag-S-VLP, by reason of consistently eliciting strong antigen-specific cellular and antibody responses, was selected for further evaluation. The purification process was improved by replacing the conventional centrifugation by serial microfiltration in the clarification step, followed by Spike-affinity chromatography to get concentrated VLPs with higher purity. Three different doses of Gag-S-VLP in conjunction with two adjuvants (Quil-A or AddaVax) were used to assess the dose-dependent antigen-specific cellular and antibody responses in mice. The Gag-S-VLP adjuvanted with Quil-A resulted in a stronger Spike-specific cellular response compared to that adjuvanted with AddaVax. A strong spike neutralisation activity was observed for all doses, independent of the adjuvant combination.

Sulfated Lactosyl Archaeol Archaeosome-Adjuvanted Vaccine Formulations Targeting Rabbit Hemorrhagic Disease Virus Are Immunogenic and Efficacious

Vaccines play an important role in maintaining human and animal health worldwide. There is continued demand for effective and safe adjuvants capable of enhancing antigen-specific responses to a target pathogen. Rabbit hemorrhagic disease virus (RHDV) is a highly contagious calicivirus that often induces high mortality rates in rabbits. Herein, we evaluated the activity of an experimental sulfated lactosyl archaeol (SLA) archaeosome adjuvant when incorporated in subunit vaccine formulations targeting RHDV. The subunit antigens consisted of RHDV-CRM₁₉₇ peptide conjugates or recombinant RHDV2 VP60. SLA was able to enhance antigen-specific antibody titers and cellular responses in mice and rabbits. Three weeks following immunization, antigen-specific antibody levels in rabbits vaccinated with RHDV2 VP60 + SLA were significantly higher than those immunized with antigen alone, with geomean titers of 7393 vs. 117. In addition, the SLA-adjuvanted VP60-based formulations were highly efficacious in a rabbit RHDV2 challenge model with up to 87.5% animals surviving the viral challenge. These findings demonstrate the potential utility of SLA adjuvants in veterinary applications and highlight its activity in different types of mammalian species.

Tuning the immune response: sulfated archaeal glycolipid archaeosomes as an effective vaccine adjuvant for induction of humoral and cell-mediated immunity towards the SARS-CoV-2 Omicron variant of concern

Liposomes composed of sulfated lactosyl archaeol (SLA) have been shown to be a safe and effective vaccine adjuvant with a multitude of antigens in preclinical studies. In particular, SLA-adjuvanted SARS-CoV-2 subunit vaccines based on trimeric spike protein antigens were shown to be immunogenic and efficacious in mice and hamsters. With the continued emergence of SARS-CoV-2 variants, we sought to evaluate next-generation vaccine formulations with an updated antigenic identity. This was of particular interest for the widespread Omicron variant, given the abundance of mutations and structural changes observed within its spike protein compared to other variants. An updated version of our resistin-trimerized SmT1 corresponding to the B.1.1.529 variant was successfully generated in our Chinese Hamster Ovary (CHO) cell-based antigen production platform and characterized, revealing some differences in protein profile and ACE2 binding affinity as compared to reference strain-based SmT1. We next evaluated this Omicron-based spike antigen for its immunogenicity and ability to generate robust antigen-specific immune responses when paired with SLA liposomes or AddaS03 (a mimetic of the AS03 oil-in-water emulsion adjuvant system found in commercialized SARS-CoV-2 protein vaccines). Immunization of mice with vaccine formulations containing this updated antigen with either adjuvant stimulated neutralizing antibody responses favouring Omicron over the reference strain. Cell-mediated responses, which play an important role in the neutralization of intracellular infections, were induced to a much higher degree with the SLA adjuvant relative to the AddaS03-adjuvanted formulations. As such, updated vaccines that are better capable of targeting towards SARS-CoV-2 variants can be generated through an optimized combination of antigen and adjuvant components.

Effect of Chiral Purity on Adjuvanticity of Archaeol-Based Glycolipids

Archaeosomes composed of sulfated lactosyl archaeol (SLA) glycolipids from stereoisomerically pure archaeol (1) are vaccine adjuvants that can boost immunogenicity and vaccine efficacy in preclinical models. Herein, we report a new synthesis of 2,3-bis((3,7,11,15-tetramethylhexadecyl)oxy) propan-1-ol (3) by treating (±)-3-benzyloxy-1,2-propanediol with a mesylated phytol derivative through a double nucleophilic substitution reaction, followed by reductive debenzylation. Three SLA archaeosomes from archaeols of different chiral purities were prepared, and the effect of stereochemistry on their adjuvanticity toward ovalbumin was investigated. It was found that all SLA archaeosomes induced strong humoral and cell-mediated antigen-specific immune responses following immunization of C57BL/6NCrl mice, with no significant differences, irrespective of the chiral purities. The responses were comparable or better than those obtained using mimetics of approved adjuvants. The performance of SLA archaeosomes during immunization and their lack of dependence on the stereochemistry of archaeol points toward a promising, safe, scalable, and economically viable vaccine adjuvant system.

Immunogenic and efficacious SARS-CoV-2 vaccine based on resistin-trimerized spike antigen SmT1 and SLA archaeosome adjuvant

The huge worldwide demand for vaccines targeting SARS-CoV-2 has necessitated the continued development of novel improved formulations capable of reducing the burden of the COVID-19 pandemic. Herein, we evaluated novel protein subunit vaccine formulations containing a resistin-trimerized spike antigen, SmT1. When combined with sulfated lactosyl archaeol (SLA) archaeosome adjuvant, formulations induced robust antigen-specific humoral and cellular immune responses in mice. Antibodies had strong neutralizing activity, preventing viral spike binding and viral infection. In addition, the formulations were highly efficacious in a hamster challenge model reducing viral load and body weight loss even after a single vaccination. The antigen-specific antibodies generated by our vaccine formulations had stronger neutralizing activity than human convalescent plasma, neutralizing the spike proteins of the B.1.1.7 and B.1.351 variants of concern. As such, our SmT1 antigen along with SLA archaeosome adjuvant comprise a promising platform for the development of efficacious protein subunit vaccine formulations for SARS-CoV-2.

Sulfated Lactosyl Archaeol Archaeosomes Synergize with Poly(I:C) to Enhance the Immunogenicity and Efficacy of a Synthetic Long Peptide-Based Vaccine in a Melanoma Tumor Model

Cancer remains a leading cause of morbidity and mortality worldwide. While novel treatments have improved survival outcomes for some patients, new treatment modalities/platforms are needed to combat a wider variety of tumor types. Cancer vaccines harness the power of the immune system to generate targeted tumor-specific immune responses. Liposomes composed of glycolipids derived from archaea (i.e., archaeosomes) have been shown to be potent adjuvants, inducing robust, long-lasting humoral and cell-mediated immune responses to a variety of antigens. Herein, we evaluated the ability of archaeosomes composed of sulfated lactosyl archaeol (SLA), a semi-synthetic archaeal glycolipid, to enhance the immunogenicity of a synthetic long peptide-based vaccine formulation containing the dominant CD8⁺ T cell epitope, SIINFEKL, from the weakly immunogenic model antigen ovalbumin. One advantage of immunizing with long peptides is the ability to include multiple epitopes, for example, the long peptide antigen was also designed to include the immediately adjacent CD4⁺ epitope, TEWTSSNVMEER. SLA archaeosomes were tested alone or in combination with the toll-like receptor 3 (TLR3) agonist Poly(I:C). Overall, SLA archaeosomes synergized strongly with Poly(I:C) to induce robust antigen-specific CD8⁺ T cell responses, which were highly functional in an in vivo cytolytic assay. Furthermore, immunization with this vaccine formulation suppressed tumor growth and extended mouse survival in a mouse melanoma tumor model. Overall, the combination of SLA archaeosomes and Poly(I:C) appears to be a promising adjuvant system when used along with long peptide-based antigens targeting cancer.

The Synergistic Effects of Sulfated Lactosyl Archaeol Archaeosomes When Combined with Different Adjuvants in a Murine Model

Archaeosomes, composed of sulfated lactosyl archaeol (SLA) glycolipids, have been proven to be an effective vaccine adjuvant in multiple preclinical models of infectious disease or cancer. SLA archaeosomes are a promising adjuvant candidate due to their ability to strongly stimulate both humoral and cytotoxic immune responses when simply admixed with an antigen. In the present study, we evaluated whether the adjuvant effects of SLA archaeosomes could be further enhanced when combined with other adjuvants. SLA archaeosomes were co-administered with five different Toll-like Receptor (TLR) agonists or the saponin QS-21 using ovalbumin as a model antigen in mice. Both humoral and cellular immune responses were greatly enhanced compared to either adjuvant alone when SLA archaeosomes were combined with either the TLR3 agonist poly(I:C) or the TLR9 agonist CpG. These results were also confirmed in a separate study using Hepatitis B surface antigen (HBsAg) and support the further evaluation of these adjuvant combinations.

Assessment of stability of sulphated lactosyl archaeol archaeosomes for use as a vaccine adjuvant

Archaeosomes, composed of sulphated lactosyl archaeol (SLA) glycolipids, have been proven to be an effective vaccine adjuvant in multiple preclinical models of infectious disease or cancer. In addition to efficacy, the stability of vaccine components including the adjuvant is an important parameter to consider when developing novel vaccine formulations. To properly evaluate the potential of SLA glycolipids to be used as vaccine adjuvants in a clinical setting, a comprehensive evaluation of their stability is required. Herein, we evaluated the long term stability of preformed empty SLA archaeosomes prior to admixing with antigen at 4 °C or 37 °C for up to 6 months. In addition, the stability of adjuvant and antigen was evaluated for up to 1 month following admixing. Multiple analytical parameters evaluating the molecular integrity of SLA and the liposomal profile were assessed. Following incubation at 4 °C or 37 °C, the SLA glycolipid did not show any pattern of degradation as determined by mass spectroscopy, nuclear magnetic resonance (NMR) and thin layer chromatography (TLC). In addition, SLA archaeosome vesicle characteristics, such as size, zeta potential, membrane fluidity and vesicular morphology, were largely consistent throughout the course of the study. Importantly, following storage for 6 months at both 4 °C and 37 °C, the adjuvant properties of empty SLA archaeosomes were unchanged, and following admixing with antigen, the immunogenicity of the vaccine formulations was also unchanged when stored at both 4 °C and 37 °C for up to 1 month. Overall this indicates that SLA archaeosomes are highly stable adjuvants that retain their activity over an extended period of time even when stored at high temperatures.

Effect of Different Adjuvants on the Longevity and Strength of Humoral and Cellular Immune Responses to the HCV Envelope Glycoproteins

Infection by Hepatitis C virus (HCV) can lead to liver cirrhosis/hepatocellular carcinoma and remains a major cause of serious disease morbidity and mortality worldwide. However, current treatment regimens remain inaccessible to most patients, particularly in developing countries, and, therefore, the development of a novel vaccine capable of protecting subjects from chronic infection by HCV could greatly reduce the rates of HCV infection, subsequent liver pathogenesis, and in some cases death. Herein, we evaluated two different semi-synthetic archaeosome formulations as an adjuvant to the E1/E2 HCV envelope protein in a murine model and compared antigen-specific humoral (levels of anti-E1/E2 IgG and HCV pseudoparticle neutralization) and cellular responses (numbers of antigen-specific cytokine-producing T cells) to those generated with adjuvant formulations composed of mimetics of commercial adjuvants including a squalene oil-in-water emulsion, aluminum hydroxide/monophosphoryl lipid A (MPLA) and liposome/MPLA/QS-21. In addition, we measured the longevity of these responses, tracking humoral, and cellular responses up to 6 months following vaccination. Overall, we show that the strength and longevity of anti-HCV responses can be influenced by adjuvant selection. In particular, a simple admixed sulfated S-lactosylarchaeol (SLA) archaeosome formulation generated strong levels of HCV neutralizing antibodies and polyfunctional antigen-specific CD4 T cells producing multiple cytokines such as IFN-γ, TNF-α, and IL-2. While liposome/MPLA/QS-21 as adjuvant generated superior cellular responses, the SLA E1/E2 admixed formulation was superior or equivalent to the other tested formulations in all immune parameters tested.

A comparison of the immune responses induced by antigens in three different archaeosome-based vaccine formulations

Archaeosomes are liposomes composed of natural or synthetic archaeal lipids that can be used as adjuvants to induce strong long-lasting humoral and cell-mediated immune responses against entrapped antigen. However, the entrapment efficiency of antigen within archaeosomes constituted using standard liposome forming methodology is often only 5-40%. In this study, we evaluated different formulation methods using a simple semi-synthetic archaeal lipid (SLA, sulfated lactosyl archaeol) and two different antigens, ovalbumin (OVA) and hepatitis B surface antigen (HBsAg). Antigen was entrapped within archaeosomes using the conventional thin film hydration-rehydration method with or without removal of non-entrapped antigen, or pre-formed empty archaeosomes were simply admixed with an antigen solution. Physicochemical characteristics were determined (size distribution, zeta potential, vesicle morphology and lamellarity), as well as location of antigen relative to bilayer using cryogenic transmission electron microscopy (TEM). We demonstrate that antigen (OVA or HBsAg) formulated with SLA lipid adjuvants using all the different methodologies resulted in a strong antigen-specific immune response. Nevertheless, the advantage of using a drug substance process that comprises of simply admixing antigen with pre-formed empty archaeosomes, represents a simple, efficient and antigenic dose-sparing formulation for adjuvanting and delivering vaccine antigens.

Lipopolysaccharide glycotyping of clarithromycin-resistant and clarithromycin-susceptible Canadian isolates of Helicobacter pylori

Lipopolysaccharide (LPS) of Helicobacter pylori exhibits several unique structures, such as Lewis (Le) antigens, α-1,6-glucan, and dd-heptan. To investigate the relationship between LPS structure and resistance to clarithromycin, 41 Canadian isolates of H. pylori were characterized by whole-cell ELISA (enzyme-linked immunosorbent assay), sugar analysis, immunoblotting, and indirect immunofluorescence. The expression of type 2 Lewis X and (or) Lewis Y antigens was detected in 22 of 23 (95.7%) clarithromycin-resistant and in 14 of 18 (77.7%) clarithromycin-susceptible H. pylori strains (P < 0.05), and 8 isolates co-expressed type 1 and type 2 Le antigens (8/41, 19.5%). A significantly higher frequency of α-1,6-glucan (P < 0.01) was detected in clarithromycin-resistant strains than in clarithromycin-susceptible strains (19/23 (82.6%) versus 11/18 (61.1%)). Sugar analysis of selected α-1,6-glucan-positive H. pylori strains confirmed that they frequently contained elevated amounts of dd-heptose. Clarithromycin-resistant isolates were also characterized by low expression levels or absence of CagA (17/23, 73.9%). Indirect immunofluorescence studies carried out on selected H. pylori strains with rabbit immune sera specific for α-1,6-glucan confirmed broad recognition of α-1,6-glucan epitope. The binding was not affected by LPS glycotype of H. pylori isolates examined nor by their CagA status or resistance to clarithromycin. These findings suggest α-1,6-glucan as a potential vaccine target, especially in an era of increasing clarithromycin resistance in H. pylori.

Potential for populations of Aedes j. japonicus to transmit Rift Valley fever virus in the USA

Aedes japonicus japonicus was introduced into the northeastern USA in 1998 and has since spread to more than 25 states. Because this species has been shown to be a competent laboratory vector of several viruses, readily feeds on large mammals, and has become a pest in several areas, there is concern that it might serve as a vector of Rift Valley fever virus (RVFV) should that virus be introduced into North America. Infection with RVFV causes mortality in > 90% of young domestic ungulates (e.g., calves, kids, and lambs), as well as causing a febrile illness and occasional deaths in humans. Therefore, we evaluated Ae. j. japonicus captured in North Carolina and in Maryland for their ability to serve as potential vectors for RVFV. After feeding on infected adult hamsters, these mosquitoes were tested for infection, dissemination, and the ability to transmit RVFV after incubation at 26 degrees C for 7-28 days. Both the Maryland and North Carolina populations of Ae. j. japonicus were highly efficient laboratory vectors of RVFV, with infection rates > 90% and dissemination rates > 84% for those mosquitoes that fed on hamsters with viremias > or = 10(8.5) plaque-forming units/ml. Thus, Ae. j. japonicus should be targeted for immediate control should RVFV be introduced into an area where this mosquito is now present.

LX4211, a dual SGLT1/SGLT2 inhibitor, improved glycemic control in patients with type 2 diabetes in a randomized, placebo-controlled trial

Thirty-six patients with type 2 diabetes mellitus (T2DM) were randomized 1:1:1 to receive a once-daily oral dose of placebo or 150 or 300 mg of the dual SGLT1/SGLT2 inhibitor LX4211 for 28 days. Relative to placebo, LX4211 enhanced urinary glucose excretion by inhibiting SGLT2-mediated renal glucose reabsorption; markedly and significantly improved multiple measures of glycemic control, including fasting plasma glucose, oral glucose tolerance, and HbA(1c); and significantly lowered serum triglycerides. LX4211 also mediated trends for lower weight, lower blood pressure, and higher glucagon-like peptide-1 levels. In a follow-up single-dose study in 12 patients with T2DM, LX4211 (300 mg) significantly increased glucagon-like peptide-1 and peptide YY levels relative to pretreatment values, probably by delaying SGLT1-mediated intestinal glucose absorption. In both studies, LX4211 was well tolerated without evidence of increased gastrointestinal side effects. These data support further study of LX4211-mediated dual SGLT1/SGLT2 inhibition as a novel mechanism of action in the treatment of T2DM.

Design and immunological properties of Helicobacter pylori glycoconjugates based on a truncated lipopolysaccharide lacking Lewis antigen and comprising an α-1,6-glucan chain

To investigate the vaccine potential of H. pylori lipopolysaccharide (LPS), truncated LPS of H. pylori strain 26695 HP0826::Kan lacking O-chain polysaccharide and comprising an extended α-1,6-linked glucan chain was conjugated to tetanus toxoid (TT) or bovine serum albumin (BSA). Two approaches were used for delipidation or partial delipidation of H. pylori LPS: (1) mild hydrolysis resulting in delipidated LPS (dLPS) and (2) treatment with anhydrous hydrazine resulting in removal of O-linked fatty acids (LPS-OH). Both LPS-OH and dLPS were covalently linked through a 2-keto-3-deoxy-octulosonic acid (Kdo) residue to a diamino group-containing spacer, followed by conjugation to thiolated TT or BSA to give conjugates LPS-OH-TT, dLPS-BSA and dLPS-TT, respectively. The LPS-OH-TT, dLPS-BSA and dLPS-TT conjugates were immunogenic in both rabbits and mice, inducing strong and specific IgG responses against homologous and heterologous strains of H. pylori. Moreover, the rabbit post-immune sera showed cross-reactivity against clinical isolates of H. pylori in a whole-cell indirect ELISA, which was further confirmed by indirect immunofluorescent microscopy. A tenfold stronger IgG immune response to the immunizing antigen was generated in mice and rabbits that received dLPS-containing conjugate. The post-immune sera of rabbits immunized with LPS-OH-TT, dLPS-BSA or dLPS-TT displayed significant bactericidal activity against mutant and wild-type α-1,6-glucan-expressing strains and selected clinical isolates of H. pylori. Finally, partial protection against H. pylori challenge was demonstrated in mice vaccinated with dLPS-TT conjugate adjuvanted with cholera toxin. In summary, this study shows that glycoconjugates based on delipidated or partially delipidated LPS from H. pylori 26695 HP0826::Kan mutant induce broadly cross-reactive functional antibodies in immunized animals and should be considered for further vaccine development and testing.

Characterization and functional activity of murine monoclonal antibodies specific for α1,6-glucan chain of Helicobacter pylori lipopolysaccharide

BACKGROUND

The outer core region of H. pylori lipopolysaccharide (LPS) contains α1,6-glucan previously shown to contribute to colonizing efficiency of a mouse stomach. The aim of the present study was to generate monoclonal antibodies (mAbs) specific for α1,6-glucan and characterize their binding properties and functional activity.

MATERIALS AND METHODS

BALB/c mice were injected intraperitoneally with 10(8) formalin-fixed H. pylori O:3 0826::Kan cells 3× over 56 days to achieve significant titer. Anti-α1,6-glucan-producing hybridomas were screened by indirect ELISA using purified H. pylori O:3 0826::Kan LPS. One clone, 1C4F9, was selected for further characterization. The specificities of mAbs were determined by indirect and inhibition ELISA using structurally defined H. pylori LPS and synthetic oligosaccharides, and whole-cell indirect ELISA (WCE) of clinical isolates. They were further characterized by indirect immunofluorescent (IF) microscopy and their functional activity in vitro determined by serum bactericidal assays against wild-type and mutant strains of H. pylori.

RESULTS

The generated anti-α1,6-glucan IgM, 1C4F9, has demonstrated an excellent specificity for the glucan chain containing 5 to 6 α1,6-linked glucose residues and showed surface accessibility by IF microscopy with H. pylori cells adherent to gastric adenocarcinoma cells monolayers. Of 38 isolates from Chile, 17 strains reacted with antiglucan mAbs in WCE (OD450 ≥ 0.2). Bactericidal activity was observed against selective wild-type and mutant H. pylori strains exhibiting OD450 values of ≥ 0.45 in WCE.

CONCLUSIONS

Anti-α1,6-glucan mAbs could have potential application in typing and surveillance of H. pylori isolates as well as offer insights into structural requirements for the development of LPS-based vaccine against H. pylori infections.

Updated distribution records for Anopheles vagus (Diptera: Culicidae) in the Republic of Philippines, and considerations regarding its secondary vector roles in Southeast Asia

Distribution records for Anopheles (Cellia) vagus in the Republic of the Philippines were updated, including recent collection and museum records from Luzon and Visayas Provinces. Larval habitats (e.g. rice paddies, irrigation and drainage ditches), associated species, and the vector potential of this species were also noted.

Influence of coronary artery disease on outcomes after liver transplantation

Patients with coronary artery disease (CAD) who undergo liver transplantation (OLT) have been previously identified as a high-risk group. Since that identification, the management of CAD has undergone significant changes as has the cardiovascular screening and selection of patients for OLT. We retrospectively identified 42 patients with known CAD who underwent OLT to compare outcomes with a control group of 42 patients without CAD who were matched for gender, age, and primary liver disease. Mortality rates were higher in the CAD than the control group at 1 year (5 vs 1) and 3 years (11 vs 3; P < .05) although lower than previously reported (at 3 years, 26% vs 50%). New cardiovascular morbidity was also more frequent among the CAD than control group at 1 year (11 vs 3; P < .05) and 3 years (16 vs 4; P < .05). Although outcomes for patients with CAD undergoing OLT are improved from historical levels, they are still worse than those in patients without CAD despite current management and selection strategies.

Effect of lidocaine on endothelin-1-mediated airway smooth muscle contraction in the rat trachea

BACKGROUND

Endothelin-1 (ET-1) is a 21-amino acid peptide that induces airway smooth muscle (ASM) constriction by activating G-protein-coupled endothelin receptors A (ETA) and B (ETB), thereby increasing intracellular calcium ([Ca(2+)]i). Lidocaine can cause direct ASM relaxation by decreasing [Ca(2+)]i. This study investigated the direct relaxant effects of lidocaine on ET-1-induced contraction in rat tracheas.

METHODS

Mid-tracheal rings (2-3 mm diameter) were excised and attached to a force transducer suspended in Krebs-Henseliet solution. Carbachol concentration-response curves (10 nM and 100 microM) were generated to determine maximal contractility (C(max)). ET-1 (3 nM to 200 nM) responses to lidocaine (100 nM, 10 microM, and 1 mM) were measured in the presence and absence of extracellular calcium. Contractile responses to ET-1 are presented as percentage of Cmax (% Cmax). Data were analyzed using analysis of variance and unpaired t-tests with Welsh correction.

RESULTS

No significant effect on ET-1-induced constriction was noted in the presence of low concentrations of lidocaine (100 nM and 1 muM), with and without extracellular calcium. At a concentration of 1 mM, lidocaine decreased the response to 100 nM and 200 nM ET-1 by 26% in the presence of extracellular calcium and by 37 and 44%, respectively, in the absence of calcium.

CONCLUSION

The attenuating effect of lidocaine (1 mM) on ET-1-induced ASM contraction is not exclusively dependent on the blockade of intracellular calcium entry.

Analysis of Helicobacter pylori isolates from Chile: occurrence of selective type 1 Lewis b antigen expression in lipopolysaccharide

Previous studies have shown that the LPS of Helicobacter pylori isolated from North American and European hosts predominantly expresses type 2 Lewis x (Le(x)) and Le(y) epitopes, whilst the LPS from Asian strains has the capacity to express type 1 Le(a) and Le(b) structures. The aim of this study was to evaluate the expression of Le antigens and the cytotoxin-associated antigen (CagA) by H. pylori isolates from Chile. A total of 38 isolates were screened. The expression of Le antigens and CagA was determined by whole-cell indirect ELISA, using commercially available monoclonal anti-Le and polyclonal anti-CagA antibodies. LPS profiles of H. pylori isolates were assessed by gel electrophoresis and Western blotting. Expression of Le(x) and/or Le(y) epitopes was confirmed in 32/38 isolates (84 %), whilst 9/38 isolates (24 %) expressed type 1 Le(b) blood group determinants, in addition to type 2 Le(x) and Le(y) structures. Six strains (16 %) were non-typeable. The majority of H. pylori strains examined were CagA-positive (83.3 %).

Carbohydrate analysis and serological classification of typical and atypical isolates of Aeromonas salmonicida: a rationale for the lipopolysaccharide-based classification of A. salmonicida

The cell envelope of Aeromonas salmonicida contains a lipopolysaccharide (LPS) essential for the physical integrity and functioning of bacterial cell membrane. Using a recently developed in-source fragmentation technique, we screened 39 typical and atypical isolates of A. salmonicida and established their O-chain polysaccharide structure by capillary electrophoresis-mass spectrometry (CE-MS), compositional and linkage analyses and comparison to the previously determined O-chain polysaccharide structure of A. salmonicida strain A449. These studies have demonstrated that A. salmonicida isolates fall into three distinct structural types, types A-C, based on chemical structures of their respective O-chain polysaccharide components. Subsequent immunoblotting and serological studies with salmon polyclonal antisera produced to formalin-fixed cells of A. salmonicida strains A449, N4705 and 33659 representing three structural types A-C revealed that variations in the O-chain polysaccharide structure have led to significant serological differences between strains belonging to type A and non-type A, where non-type A species include chemically separated structural types B and C. Due to the presence of common antigenic determinants shared by their respective O-chain polysaccharide components, serological cross-reactions were observed between A. salmonicida strains belonging to structural types B and C. These findings suggest the possibility of developing LPS-based classification system of A. salmonicida sub-species consisting of two serologically distinct types, type A and non-type A.

Helicobacter pylori cagA and iceA genotypes status and risk of peptic ulcer in Saudi patients

OBJECTIVE

To determine the prevalence of cagA+ and iceA genotypes among Helicobacter pylori (H. pylori) isolates from a group of Saudi patients with gastric complaints, and to find out any significant correlation between these strains and severe gastric clinical outcomes such as peptic ulcer and gastric cancer in Saudi population.

METHODS

A total of 1104 gastric biopsies from 368 patients who presented with symptoms suggestive of chronic gastritis, peptic ulcer disease, or gastric carcinoma were taken from the main hospitals in the Western region of Saudi Arabia from July 2004 to July 2005. We cultured the samples for H. pylori and a polymerase chain reaction was carried out to check for the presence or absence of cagA gene and the status of iceA genotypes.

RESULTS

Among the 368 suspected patients to be infected with H. pylori by means of clinical features and endoscopic findings; 103 (28%) were positive using culture technique. The relation of the presence of cagA and the development of cases to gastritis and ulcer was statistically significant (p=0.0001). Furthermore, this study revealed that 100% of ulcer cases were infected with iceA1 with a statistically significant correlation (p=0.0001), while 94.6% of gastritis and 90.9% of normal were infected with iceA2 (p=0.0001). Moreover cagA+/iceA1 combined genotypes was statistically correlated with peptic ulcer (100%) but not cagA-/iceA1 (0%; p=0.0001).

CONCLUSION

Certain H. pylori genotypes were more virulent than others. Multiple clinical implications based on these finding might be studied further.

Characterization of murine monoclonal antibodies against Helicobacter pylori lipopolysaccharide specific for Lex and Ley blood group determinants

The cell envelope of Helicobacter pylori contains lipopolysaccharide (LPS), the O-chain of which expresses type 2 Lex and Ley blood group antigens, which mimic human gastric mucosal cell-surface glycoconjugates and may contribute to the survival of H. pylori in gastric mucosa. Here we describe the generation of monoclonal antibodies specific for Lex and Ley blood group determinants and the characterization of their binding properties using purified, structurally defined H. pylori LPS, synthetic glycoconjugates, and H. pylori cells. Analysis of oligosaccharide binding by SPR provided a rapid and reliable means for characterization of antibody affinities. One of the antibodies, anti-Lex, was of IgG3 subclass and had superior binding characteristics as compared with the commercially available anti-Lex IgM. These antibodies could have potential in the immunodiagnosis of certain types of cancer, in serotyping of H. pylori isolates, and in structure-function studies.

Occurrence and relative abundance of mosquitoes in stormwater retention facilities in North Carolina, U.S.A

Throughout the 2004 mosquito season, 52 stormwater retention facilities were sampled to characterize the seasonal occurrence and relative abundance of mosquito species in relation to the structural complexity and biological diversity of the facilities. The three different types of facilities included standard wet ponds (n=20), innovative ponds (n=14), and wetland ponds (n=18). All retention structures were sampled at the beginning, middle and end of the mosquito season so that seasonal changes in mosquito production could be characterized. Overall samplings, mosquitoes were collected from 34% of the retention structures. Fourteen species representing 7 genera were collected, but only 5 species were commonly collected in all three types of stormwater management facilities. In general, the seasonal prevalence and relative abundance of mosquito species did not vary among three types of retention structures. A significant association (P < 0.01) between the presence of mosquito larvae or pupae and the absence of mosquitofish was found for innovative and wetland stormwater retention facilities but not for standard retention facilities (P > 0.05).

Identification of a D-glycero-D-manno-heptosyltransferase gene from Helicobacter pylori

We have identified a Helicobacter pylori d-glycero-d-manno-heptosyltransferase gene, HP0479, which is involved in the biosynthesis of the outer core region of H. pylori lipopolysaccharide (LPS). Insertional inactivation of HP0479 resulted in formation of a truncated LPS molecule lacking an alpha-1,6-glucan-, dd-heptose-containing outer core region and O-chain polysaccharide. Detailed structural analysis of purified LPS from HP0479 mutants of strains SS1, 26695, O:3, and PJ1 by a combination of chemical and mass spectrometric methods showed that HP0479 likely encodes alpha-1,2-d-glycero-d-manno-heptosyltransferase, which adds a d-glycero-d-manno-heptose residue (DDHepII) to a distal dd-heptose of the core oligosaccharide backbone of H. pylori LPS. When the wild-type HP0479 gene was reintegrated into the chromosome of strain 26695 by using an "antibiotic cassette swapping" method, the complete LPS structure was restored. Introduction of the HP0479 mutation into the H. pylori mouse-colonizing Sydney (SS1) strain and the clinical isolate PJ1, which expresses dd-heptoglycan, resulted in the loss of colonization in a mouse model. This indicates that H. pylori expressing a deeply truncated LPS is unable to successfully colonize the murine stomach and provides evidence for a critical role of the outer core region of H. pylori LPS in colonization.

Structural and serological characterization of the O-chain polysaccharide of Aeromonas salmonicida strains A449, 80204 and 80204-1

The O-chain polysaccharide (O-PS) of Aeromonas salmonicida was studied by a combination of compositional, methylation, CE-ESMS and one- and two-dimensional NMR analyses. It was found to be a branched polymer of trisaccharide-repeating units composed of L-rhamnose (Rha), D-glucose (Glc), 2-acetamido-2-deoxy-D-mannose (ManNAc) and O-acetyl group (OAc) and having the following structure: CE-ESMS analysis of A. salmonicida cells from strains A449, 80204 and 80204-1 grown under different conditions confirmed that the O-PS structure was conserved. ELISA-based serological study with native LPS-specific antisera performed on the native O-PS and its O-deacetylated and periodate-oxidized derivatives confirmed the importance of the O-PS backbone structure as an immunodominant determinant.

Galectin-3-mediated adherence of Proteus mirabilis to Madin-Darby canine kidney cells

Proteus mirabilis is an important cause of urinary tract infections (UTIs) and can result in acute pyelonephritis. Proteus mirabilis expresses several, morphologically distinct, fimbrial species, and previous studies have shown that the nonagglutinating fimbriae (NAF) mediate bacterial adherence to a number of cell lines, including Madin-Darby canine kidney (MDCK) cells. Immunoblot overlay analysis of the plasma membrane fraction from MDCK cells with purified NAF revealed a 34-kDa band, which has been analyzed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Database search identified galectin-3 as a potential protein candidate. Immunocytochemical assay of MDCK cells with a galectin-3-specific monoclonal antibody, anti-Mac-2, confirmed its presence on the plasma membrane extracellular surface. Preincubation of P. mirabilis with anti-Mac-2 monoclonal antibodies, specific for galectin-3, resulted in the inhibition of bacterial binding to MDCK cells. These data suggest a role for galectin-3, interacting with appropriately glycosylated surface receptors and P. mirabilis fimbriae, as a mediator of bacterial adherence in vitro.

Galectin-3-mediated adherence ofProteus mirabilisto Madin-Darby canine kidney cells

Proteus mirabilis is an important cause of urinary tract infections (UTIs) and can result in acute pyelonephritis. Proteus mirabilis expresses several, morphologically distinct, fimbrial species, and previous studies have shown that the nonagglutinating fimbriae (NAF) mediate bacterial adherence to a number of cell lines, including Madin-Darby canine kidney (MDCK) cells. Immunoblot overlay analysis of the plasma membrane fraction from MDCK cells with purified NAF revealed a 34-kDa band, which has been analyzed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Database search identified galectin-3 as a potential protein candidate. Immunocytochemical assay of MDCK cells with a galectin-3-specific monoclonal antibody, anti-Mac-2, confirmed its presence on the plasma membrane extracellular surface. Preincubation of P. mirabilis with anti-Mac-2 monoclonal antibodies, specific for galectin-3, resulted in the inhibition of bacterial binding to MDCK cells. These data suggest a role for galectin-3, interacting with appropriately glycosylated surface receptors and P. mirabilis fimbriae, as a mediator of bacterial adherence in vitro.Key words: bacterial adherence, fimbriae, galectin-3, mass spectrometry.

Identification of selective inhibitors of cyclin dependent kinase 4

A new structural type of kinase inhibitor, containing a benzocarbazole nucleus, has been identified. Members of the series are selective for inhibition of the cyclin dependent kinase family of enzymes. Although the cdks are highly homologous, representatives of the series showed intra-cdk selectivities, especially for cdk4. SAR studies elucidated the important features of the molecules for inhibition.

The synthesis of an exhaustively stereodiversified library of cis-1,5 enediols by silyl-tethered ring-closing metathesis

[reaction: see text] This report describes the parallel synthesis of all 16 stereoisomers of the cis-1,5 enediol module 1. Compounds 1 derive from 2 by silicon-tethered ring-closing metathesis. Such libraries of stereodiversified ligands provide a unique approach to ligand discovery that employs exhaustive searching of conformational space.

Evaluation of 1-octen-3-ol, carbon dioxide, and light as attractants for mosquitoes associated with two distinct habitats in North Carolina

Field studies were conducted in North Carolina to determine the responses of mosquitoes found in salt marsh and inland creek flood plain areas to 1-octen-3-ol (octenol), carbon dioxide (CO2), and light in various combinations with Centers for Disease Control (CDC) light traps. Over 56,000 adult mosquito specimens of 12 species in 4 genera were collected in the salt marsh. They exhibited a general response pattern of octenol + CO2 + light > CO2 + light = octenol + CO2 > octenol + light > octenol alone. Significantly, more Aedes sollicitans, Ae. taeniorhynchus, Anopheles bradleyi, and Culex salinarius were attracted to octenol + CO2 + light than to CO2 + light. Over 19,000 specimens of 24 species in 7 genera were collected in the inland creek flood plain. Although the response patterns to the attractants were similar to those in the salt marsh area, there was no significant difference between octenol + CO2 + light and CO2 + light. Aedes vexans, An. crucians, and An. punctipennis were attracted nearly equally to these two attractant combinations. These studies demonstrate that responses to combinations of these attractants are species specific. However, different combinations of attractants can significantly increase the collection of targeted species important in arbovirus transmission. The use of these combinations would be very beneficial in mosquito-borne virus surveillance studies. The use of octenol by itself or in conjunction with light was found the least useful for collecting mosquitoes in both habitats.

The binding ofProteus mirabilisnonagglutinating fimbriae to ganglio-series asialoglycolipids and lactosyl ceramide

Proteus mirabilis is a common opportunistic Gram-negative uropathogen that infects the upper urinary tract. We have examined the role of the nonagglutinating fimbriae (NAF) of P. mirabilis in mediating bacterial adhesion to cell surface receptors. Purified NAF of P. mirabilis were demonstrated to bind to a number of glycolipids, including asialo-GM1, asialo-GM2, and lactosyl ceramide (LacCer) in solid-phase binding assays and in thin layer chromatography (TLC) overlay assays. Furthermore, preincubation of the biotinylated NAF (Bt-NAF) with anti-NAF monoclonal antibodies resulted in inhibition of NAF binding to immobilized asialo-GM1, asialo-GM2, and LacCer. In adherence assays, P. mirabilis binding to Madin-Darby canine kidney (MDCK) cells was inhibited by murine anti-asialo-GM1 monoclonal antibodies H2G10 to about 50% of the binding level in the absence of the antibody, specific for the terminal β-galactopyranosyl residue of asialo-GM1 (Harrison et al. 1998). The results of this study suggest that NAF of P. mirabilis recognize a GalNAcβ1-4Gal moiety present in the ganglio-series of asialoglycolipids, and that the terminal β-galactopyranosyl -containing glycoconjugates play a role in NAF-mediated adherence of P. mirabilis to MDCK cells. Similarly to other bacteria, P. mirabilis NAF was also shown to express the LacCer specificity.Key words: bacterial adhesion, Proteus mirabilis, fimbriae, receptors, glycosphingolipids.

The binding of Proteus mirabilis nonagglutinating fimbriae to ganglio-series asialoglycolipids and lactosyl ceramide

Proteus mirabilis is a common opportunistic Gram-negative uropathogen that infects the upper urinary tract. We have examined the role of the nonagglutinating fimbriae (NAF) of P. mirabilis in mediating bacterial adhesion to cell surface receptors. Purified NAF of P. mirabilis were demonstrated to bind to a number of glycolipids, including asialo-GM1, asialo-GM2, and lactosyl ceramide (LacCer) in solid-phase binding assays and in thin layer chromatography (TLC) overlay assays. Furthermore, preincubation of the biotinylated NAF (Bt-NAF) with anti-NAF monoclonal antibodies resulted in inhibition of NAF binding to immobilized asialo-GM1, asialo-GM2, and LacCer. In adherence assays, P. mirabilis binding to Madin-Darby canine kidney (MDCK) cells was inhibited by murine anti-asialo-GM1 monoclonal antibodies H2G10 to about 50% of the binding level in the absence of the antibody, specific for the terminal beta-galactopyranosyl residue of asialo-GM1 (Harrison et al. 1998). The results of this study suggest that NAF of P. mirabilis recognize a GalNAc beta 1-4Gal moiety present in the ganglio-series of asialoglycolipids, and that the terminal beta-galactopyranosyl-containing glycoconjugates play a role in NAF-mediated adherence of P. mirabilis to MDCK cells. Similarly to other bacteria, P. mirabilis NAF was also shown to express the LacCer specificity.

Inhaled nitric oxide reduces pulmonary artery pressures in portopulmonary hypertension

Pulmonary artery hypertension in association with liver failure (portopulmonary hypertension [PPHTN]) is a significant barrier to liver transplantation because patients with this condition have a very high mortality when transplantation is undertaken. Inhaled nitric oxide (NO), a potent pulmonary vasodilator, reduces pulmonary artery pressure (PAP) in some patients with primary pulmonary hypertension, but its effect in patients with PPHTN is controversial. We investigated the hemodynamic effects of inhaled NO in 6 patients with PPHTN. Five of 6 patients responded to NO inhalation with decreases in PAP and pulmonary vascular resistance of greater than 10%; these decreases were statistically significant at NO concentrations of 10 and 30 ppm. Cardiac output did not significantly change. We conclude that inhalation of NO reduces PAPs in some patients with PPHTN.

Preclinical antitumor efficacy of analogs of XK469: sodium-(2-[4-(7-chloro-2-quinoxalinyloxy)phenoxy]propionate

A series of quinoxaline analogs of the herbicide Assure was found to have selective cytotoxicity for solid tumors of mice in a disk-diffusion-soft-agar-colony-formation-assay compared to L1210 leukemia. Four agents without selective cytotoxicity and 14 agents with selective cytotoxicity were evaluated in vivo for activity against a solid tumor. The four agents without selective cytotoxicity in the disk-assay were inactive in vivo (T/C > 42%). Thirteen of the fourteen agents with selectivity in the disk-assay were active in vivo (T/C < 42%). Five of the agents had curative activity. These five agents had a halogen (F, Cl, Br) in the 7-position (whereas Assure had a CI in the 6 position). All agents with curative activity were either a carboxylic acid, or a derivative thereof, whereas Assure is the ethyl ester of the carboxylic acid. All other structural features were identical between Assure and the curative agents. Assure had no selective cytotoxicity for solid tumors in the disk-assay, and was devoid of antitumor activity. The analog XK469 is in clinical development.

North Carolina mosquito records. I. Uncommon Aedes and Anopheles (Diptera: Culicidae)

New distribution records are provided for 10 mosquito species that are rare or uncommon in North Carolina: Aedes aegypti, Ae. cinereus, Ae. dupreei, Ae. fulvus pallens, Ae. hendersoni, Ae. mitchellae, Ae. thibaulti, Ae. tormentor, Ae. trivittatus, and Anopheles atropos. Biological notes are provided for habitats, behavior, and, in some cases, color patterns. Comments are also made about 6 additional species that are rare or uncommon in North Carolina.

A kinetics approach to the characterization of an IgM specific for the glycolipid asialo-GM1

The unique features of protein recognition of membrane-anchored glycolipids were investigated by surface plasmon resonance (SPR) monitoring of antibody interactions with glycolipids contained in liposomes. Several positive hybridomas belonging to the IgM and IgG classes were identified when tested for binding to the glycosphingolipid asialo-GM1 (Gal beta1-3GalNAcl beta1-4Gal beta1-4Glc beta1-1-Ceramide). Preliminary screening by enzyme immunoassay and thin layer chromatography (TLC) followed by immunostaining indicated that only those of the IgM type showed specificity for this glycosphingolipid. One of the IgMs, H2G10, was purified and further characterized using a SPR technique that involved antibody binding to liposomal asialo-GM1. This method generated kinetic and affinity constants for the interaction and confirmed the specificity of H2G10 for the terminal galactose of asialo-GM1. Interestingly, inhibition of antibody binding to asialo-GM1 liposomes by the asialo-GM1 tetrasaccharide reduced the total amount of bound antibody but increased the affinity of the antigen-antibody interaction due to an inverse relationship between tetrasaccharide concentration and the H2G10 dissociation rate constant. We believe that this effect is due to the selective inhibition of lower valency binding by the tetrasaccharide which, in turn, promotes higher avidity antibody-carbohydrate interactions. The observation that slower dissociation rate constants were also observed at high antigen to antibody ratios supports this interpretation. These results highlight the insight that kinetic data can provide in efforts to promote and inhibit high avidity interactions such as those involving proteins and carbohydrates.

The expression of nonagglutinating fimbriae and its role in Proteus mirabilis adherence to epithelial cells

Proteus mirabilis is a common causative agent of human urinary tract infections, especially in catheterized patients and in those patients with structural abnormalities of the urinary tract. In addition to the production of hemolysin and urease, fimbriae-mediated adherence to uroepithelial cells and kidney epithelium may be essential for virulence of P. mirabilis. A single P. mirabilis strain is capable of expressing several morphologically distinct fimbrial species, which can each be favoured by specific in vitro growth conditions. The fimbrial species reported to date include mannose-resistant/Proteus-like fimbriae, ambient temperature fimbriae, P. mirabilis fimbriae, and nonagglutinating fimbriae (NAF). Here, using intact bacteria or purified NAF as immunogens, we have generated the first reported NAF-specific monoclonal antibodies (mAbs). Bacteria expressing NAF as their only fimbrial species adhered strongly to a number of cell lines in vitro, including uroepithelial cell lines. Binding of P. mirabilis was markedly reduced following preincubation with NAF-specific mAbs and Fab fragments. The presence of NAF with highly conserved N-terminal sequences on all P. mirabilis strains so far examined, combined with the ability of both anti-NAF mAbs and purified NAF molecules to inhibit P. mirabilis adherence in vitro, suggests that NAF may contribute to the pathogenesis of P. mirabilis.

Ticks (Acari: Ixodida) uncommonly found biting humans in North Carolina

Collection records are presented that document human-biting by Otobius megnini, Amblyomma maculatum, Haemaphysalis leporispalustris, Ixodes cookei, Ixodes dentatus, and Rhipicephalus sanguineus in North Carolina. These species are either extremely rare in North Carolina or they are normally considered non-human feeders. The record of Otobius megnini represents the first collection of this species in North Carolina in over 50 years. It is proposed that immature Rhipicephalus sanguineus feed on humans much more than previously suspected and that they represent a threat for the transmission of pathogens to humans.

Identifying Psorophora horrida females in North Carolina (Diptera:Culicidae)

Morphological characters to separate Psorophora horrida (Dyar and Knab) and Psorophora ferox (Von Humboldt) females are identified and defined. In addition to the 3 characters used to separate these 2 species in published keys, an additional 6 characters were found. Of the total of 9 characters identified, 6 are reliable at the 100% level, based on North Carolina specimens. These additional characters will assist greatly in identifying Ps, horrida specimens. Variation or hindtarsomere 4 of Ps. horrida, consisting of dark-scaled patterns, were also noted. Characters for separating Psorophora cyanescens (Coq.) and Psorophora mathesoni Belkin and Heinemann from Ps. ferox and Ps. horrida are discussed.

The HeLa cell receptor for enterovirus 70 is decay-accelerating factor (CD55)

Enterovirus 70 (EV70) is a recently emerged human pathogen belonging to the family Picornaviridae. The ability of EV70 to infect a wide variety of nonprimate cell lines in vitro is unique among human enteroviruses. The importance of virus receptors as determinants of viral host range and tropism led us to study the host cell receptor for this unusual picornavirus. We produced a monoclonal antibody (MAb), EVR1, which bound to the surface of HeLa cells and protected them against infection by EV70 but not by poliovirus or by coxsackievirus B3. This antibody also inhibited the binding of [35S]EV70 to HeLa cells. MAb EVR1 did not bind to monkey kidney (LLC-MK2) cells, nor did it protect these cells against virus infection. In Western immunoassays and in immunoprecipitations, MAb EVR1 identified a HeLa cell glycoprotein of approximately 75 kDa that is attached to the cell membrane by a glycosyl-phosphatidylinositol (GPI) anchor. Decay-accelerating factor (DAF, CD55) is a 70- to 75-kDa GPI-anchored membrane protein that is involved in the regulation of complement and has also been shown to function as a receptor for several enteroviruses. MAb EVR1 bound to Chinese hamster ovary (CHO) cells constitutively expressing human DAF. Anti-DAF MAbs inhibited EV70 binding to HeLa cells and protected them against EV70 infection. Transient expression of human DAF in murine NIH 3T3 cells resulted in binding of labelled EV70 and stably, transformed NIH 3T3 cells expressing DAF were able to support virus replication. These data indicate that the HeLa cell receptor for EV70 is DAF.

Production and characterization of monoclonal antibodies to Actinobacillus pleuropneumoniae serotype 5b

Monoclonal antibodies specific for capsular polysaccharide (CPS) and lipopolysaccharide (LPS) of A. pleuropneumoniae serotype 5b were generated by hybridoma cells and selected by indirect ELISA of culture supernatants with purified and structurally defined LPS and CPS preparations and their synthetic conjugates. It was shown in this study that at least one monoclonal antibody, 3B4, presented 100% specificity and recognized all A. pleuropneumoniae serotype 5 field strains tested in a dot-ELISA assay.

Opioids and benzodiazepines

Most patients in the intensive care unit experience pain and anxiety, which are treated most commonly with an opioid or a benzodiazepine. These compounds are effective and have a well-established safety record. With the exception of associated respiratory depression, they have a relatively wide therapeutic window. New approaches and formulations for opioids and benzodiazepines are being used with continued success in the clinical setting.