Could a B-1 Cell Derived Phagocyte “Be One” of the Peritoneal Macrophages during LPS-Driven Inflammation?

The inflammatory response is driven by signals that recruit and elicit immune cells to areas of tissue damage or infection. The concept of a mononuclear phagocyte system postulates that monocytes circulating in the bloodstream are recruited to inflamed tissues where they give rise to macrophages. A recent publication demonstrated that the large increase in the macrophages observed during infection was the result of the multiplication of these cells rather than the recruitment of blood monocytes. We demonstrated previously that B-1 cells undergo differentiation to acquire a mononuclear phagocyte phenotype in vitro (B-1CDP), and we propose that B-1 cells could be an alternative origin for peritoneal macrophages. A number of recent studies that describe the phagocytic and microbicidal activity of B-1 cells in vitro and in vivo support this hypothesis. Based on these findings, we further investigated the differentiation of B-1 cells into phagocytes in vivo in response to LPS-induced inflammation. Therefore, we investigated the role of B-1 cells in the composition of the peritoneal macrophage population after LPS stimulation using osteopetrotic mice, BALB/Xid mice and the depletion of monocytes/macrophages by clodronate treatment. We show that peritoneal macrophages appear in op/op((-/-)) mice after LPS stimulation and exhibit the same Ig gene rearrangement (VH11) that is often found in B-1 cells. These results strongly suggest that op/op((-/-)) peritoneal "macrophages" are B-1CDP. Similarly, the LPS-induced increase in the macrophage population was observed even following monocyte/macrophage depletion by clodronate. After monocyte/macrophage depletion by clodronate, LPS-elicited macrophages were observed in BALB/Xid mice only following the transfer of B-1 cells. Based on these data, we confirmed that B-1 cell differentiation into phagocytes also occurs in vivo. In conclusion, the results strongly suggest that B-1 cell derived phagocytes are a component of the LPS-elicited peritoneal macrophage population.     

Optimization of laccase production by Botryosphaeria sp. in the presence of veratryl alcohol by the response-surface method

Botryosphaeria sp. produced two laccases (PPO-I and PPO-II) constitutively, whose titers were enhanced by veratryl alcohol. The effect of veratryl alcohol and yeast extract concentration, time of cultivation and agitation speed were evaluated by factorial analysis to select variables for optimizing the production of laccases. Maximal laccase production was determined using a second-order central-composite design and analyzed by the response-surface method. Veratryl alcohol concentration and time of cultivation were the main factors increasing laccase production, while yeast extract had no influence within the range 0.2–2.0% w/v. Response-surface analysis showed that 30.4 mM veratryl alcohol, for 4.5 days at 28°C and 180 rpm, were the optimal conditions to maximize PPO-I production, while conditions for maximal PPO-II production occurred within a range of 28–35 mM veratryl alcohol over a growth period of 4–5.5 days. The model predicted 5.6 U ml⁻¹ for PPO-I, and 0.6–1.0 U ml⁻¹ for PPO-II, which agreed with the experimentally observed results.     

Use of a Recombinant Cysteine Proteinase from Leishmania (Leishmania) infantum chagasi for the Immunotherapy of Canine Visceral Leishmaniasis

Background

A recombinant cysteine proteinase from Leishmania (Leishmania) infantum chagasi (rLdccys1) was previously shown to induce protective immune responses against murine and canine visceral leishmaniasis. These findings encouraged us to use rLdccys1 in the immunotherapy of naturally infected dogs from Teresina, Piauí, a region of high incidence of visceral leishmaniasis in Brazil.

Methodology/Principal Findings

Thirty naturally infected mongrel dogs displaying clinical signs of visceral leishmaniasis were randomly divided in three groups: one group received three doses of rLdccys1 in combination with the adjuvant Propionibacterium acnes at one month interval between each dose; a second group received three doses of P. acnes alone; a third group received saline. The main findings were: 1) dogs that received rLdccys1 with P. acnes did not display increase of the following clinical signs: weight loss, alopecia, onychogryphosis, cachexia, anorexia, apathy, skin lesions, hyperkeratosis, ocular secretion, and enlarged lymph nodes; they also exhibited a significant reduction in the spleen parasite load in comparison to the control dogs; 2) rLdccys1-treated dogs exhibited a significant delayed type cutaneous hypersensitivity elicited by the recombinant antigen, as well as high IgG2 serum titers and low IgG1 serum titers; sera from rLdccys1-treated dogs also contained high IFN-γ and low IL-10 concentrations; 3) control dogs exhibited all of the clinical signs of visceral leishmaniasis and had low serum IgG2 and IFN-γ levels and high concentrations of IgG1 and IL-10; 4) all of the dogs treated with rLdccys1 were alive 12 months after treatment, whereas dogs which received either saline or P. acnes alone died within 3 to 7 months.

Conclusions/Significance

These findings illustrate the potential use of rLdccys1 as an additional tool for the immunotherapy of canine visceral leishmaniasis and support further studies designed to improve the efficacy of this recombinant antigen for the treatment of this neglected disease.     

Flufenamic acid as an inducer of mitochondrial permeability transition

To assess the mechanism by which mitochondrial permeability transition (MPT) is induced by the nonpolar carboxylic acids, we investigated the effects of flufenamic acid (3-trifluoromethyl diphenylamine-2-carboxylic acid, FA) on mitochondrial respiration, electrical transmembrane potential difference (), osmotic swelling, Ca²⁺ efflux, NAD(P)H oxidation and reactive oxygen species (ROS) generation. Succinate-energized isolated rat liver mitochondria incubated in the absence or presence of 10 M Ca²⁺, 5 M ruthenium red (RR) or 1 M cyclosporin A (CsA) were used. The dose response-curves for both respiration release and dissipation were nearly linear, presenting an IC₅₀ of approximately 10 M and reaching saturation within 25-50 M, indicating that FA causes mitochondrial uncoupling by a protonophoric mechanism. Within this same concentration range FA showed the ability to induce MPT in energized mitochondria incubated with 10 M Ca²⁺, followed by dissipation and Ca²⁺ efflux, and even in deenergized mitochondria incubated with 0.5 mM Ca²⁺. ADP, Mg²⁺, trifluoperazine (TFP) and N-ethylmaleimide (NEM) reduced the extent of FA-promoted swelling in energized mitochondria by approximately one half, whereas dithiothreitol (DTT) slightly enhanced it. NAD(P)H oxidation and ROS generation (H₂O₂ production) by mitochondria were markedly stimulated by FA; these responses were partly prevented by CsA, suggesting that they may be implicated as both a cause and effect of FA-induced MPT. FA incubated with mitochondria under swelling assay conditions caused a decrease of approximately 40% in the content of protein thiol groups reacting with 5,5-dithiobis(2-nitrobenzoic acid) (DTNB). The present results are consistent with a ROS-intermediated sensitization of MPT by a direct or indirect FA interaction with inner mitochondrial membrane at a site which is in equilibrium with the NAD(P)H pool, namely thiol groups of integral membrane proteins.     

Novel polyamine-dialkyl phosphate conjugates for gene carriers. Facile synthetic route via an unprecedented dialkyl phosphate

To develop a novel nonviral gene carrier, three types of polyamine-dialkyl phosphates conjugates were synthesized via an unprecedented synthetic intermediate, dimerized dicetyl phosphate (DCP) anhydride, and the transfection efficiency and the complexation properties of the conjugate-DNA were evaluated. Condensation of DCP by 1,3,5-triisopropylbenzenesulfonyl chloride, TPSCl, gives the dimerized anhydride, which is stable enough to isolate by column chromatography in approximately 90% yield. The anhydride is reactive with various amines, i.e., spermidine, spermine, and polyethylenimine (PEI(1800)), providing corresponding polyamine-DCP conjugates via phosphoramidate linkage. The polyamine-DCP conjugates exhibited moderate transfection efficacy evaluated by beta-galactosidase assay. The conjugate-DNA complex was observed by using an atomic force microscope (AFM), revealing that the PEI(1800)-DCP conjugate, which showed the most efficient transfection, enables the formation of the more compact complex with DNA.     

Evolution of cyclophilin A and TRIMCyp retrotransposition in New World primates

Host cell factors modulate retroviral infections. Among those, cyclophilin A (CypA) promotes virus infectivity by facilitating virus uncoating or capsid unfolding or by preventing retroviral capsid interaction with cellular restriction factors. In Aotus species, a retrotransposed copy of CypA inserted into the tripartite motif 5 (TRIM5) gene encodes a fusion protein which may block human immunodeficiency virus type 1 by targeting the incoming virus to ubiquitin-ligated degradation or by interfering with normal uncoating of the incoming particle, rendering those monkeys resistant to infection. In this study, we have extensively analyzed representative specimens from all New World primate genera and shown that the retrotransposed CypA copy is only present in Aotus. We have shown that this inserted copy diverged from its original counterpart and that this occurred prior to Aotus radiation, although no positive selection was observed. Finally, our data underscores the need for a precise taxonomic identification of primate species used as models for retroviral infections and novel antiviral approaches.     

Development of a fluorescent probe for detection of citrulline based on photo-induced electron transfer

Peptidyl arginine deiminases (PADs) catalyze the post-translational deimination of peptidyl arginine residues to form citrulline residues. Aberrant citrullination of histones by one of the PAD isozymes, PAD4, is associated with various diseases, including rheumatoid arthritis, so high-throughput screening systems are needed to identify PAD4 inhibitors as chemical tools to investigate the role of PAD4, and as candidate therapeutic agents. Here, we utilized the addition-cyclization reaction between phenylglyoxal and citrulline under acidic conditions to design turn-on fluorescent probes for citrulline based on the donor-excited photoinduced electron transfer (d-PeT) mechanism. Among several derivatives of phenylglyoxal bearing a fluorescent moiety, we found that FGME enabled detection of citrulline without a neutralization process, and we used it to establish a simple methodology for turn-on fluorescence detection of citrulline.     

MAIR‐II deficiency ameliorates cardiac remodelling post‐myocardial infarction by suppressing TLR9‐mediated macrophage activation

Macrophages are fundamental components of inflammation in post‐myocardial infarction (MI) and contribute to adverse cardiac remodelling and heart failure. However, the regulatory mechanisms in macrophage activation have not been fully elucidated. Previous studies showed that myeloid‐associated immunoglobulin–like receptor II (MAIR‐II) is involved in inflammatory responses in macrophages. However, its role in MI is unknown. Thus, this study aimed to determine a novel role and mechanism of MAIR‐II in MI. We first identified that MAIR‐II–positive myeloid cells were abundant from post‐MI days 3 to 5 in infarcted hearts of C57BL/6J (WT) mice induced by permanent left coronary artery ligation. Compared to WT, MAIR‐II–deficient (Cd300c2 ^−/−) mice had longer survival, ameliorated cardiac remodelling, improved cardiac function and smaller infarct sizes. Moreover, we detected lower pro‐inflammatory cytokine and fibrotic gene expressions in Cd300c2 ^−/−‐infarcted hearts. These mice also had less infiltrating pro‐inflammatory macrophages following MI. To elucidate a novel molecular mechanism of MAIR‐II, we considered macrophage activation by Toll‐like receptor (TLR) 9–mediated inflammation. In vitro, we observed that Cd300c2 ^−/− bone marrow–derived macrophages stimulated by a TLR9 agonist expressed less pro‐inflammatory cytokines compared to WT. In conclusion, MAIR‐II may enhance inflammation via TLR9‐mediated macrophage activation in MI, leading to adverse cardiac remodelling and poor prognosis.     

Immunogenicity and reactogenicity of 2009 influenza A (H1N1) inactivated monovalent non-adjuvanted vaccine in elderly and immunocompromised patients

Background

Immunosuppressed individuals present serious morbidity and mortality from influenza, therefore it is important to understand the safety and immunogenicity of influenza vaccination among them.

Methods

This multicenter cohort study evaluated the immunogenicity and reactogenicity of an inactivated, monovalent, non-adjuvanted pandemic (H1N1) 2009 vaccine among the elderly, HIV-infected, rheumatoid arthritis (RA), cancer, kidney transplant, and juvenile idiopathic arthritis (JIA) patients. Participants were included during routine clinical visits, and vaccinated according to conventional influenza vaccination schedules. Antibody response was measured by the hemagglutination-inhibition assay, before and 21 days after vaccination.

Results

319 patients with cancer, 260 with RA, 256 HIV-infected, 149 elderly individuals, 85 kidney transplant recipients, and 83 with JIA were included.The proportions of seroprotection, seroconversion, and the geometric mean titer ratios postvaccination were, respectively: 37.6%, 31.8%, and 3.2 among kidney transplant recipients, 61.5%, 53.1%, and 7.5 among RA patients, 63.1%, 55.7%, and 5.7 among the elderly, 59.0%, 54.7%, and 5.9 among HIV-infected patients, 52.4%, 49.2%, and 5.3 among cancer patients, 85.5%, 78.3%, and 16.5 among JIA patients. The vaccine was well tolerated, with no reported severe adverse events.

Conclusions

The vaccine was safe among all groups, with an acceptable immunogenicity among the elderly and JIA patients, however new vaccination strategies should be explored to improve the immune response of immunocompromised adult patients. (ClinicalTrials.gov, {"type":"clinical-trial","attrs":{"text":"NCT01218685","term_id":"NCT01218685"}}NCT01218685)