OmpU and OmpC are the key OMPs for Litopenaeus vannamei hemocyanin recognizes Vibrio parahaemolyticus

Hemocyanin is a multifunctional protein present in arthropods and mollusks, responsible for oxygen transport and participating in multiple roles of immune defense including antibacterial activity. However, the molecular basis of how hemocyanin recognizes pathogens and exerts antibacterial activity remains poorly understood. In the present study, the pull-down assay was used to isolate Vibrio parahaemolyticus outer membrane proteins (OMPs) that bind to Litopenaeus vannamei hemocyanin. Two interacting OMPs bands were determined as OmpC and OmpU, and the heterogeneous interaction between hemocyanin and the two OMPs was further confirmed by far-Western blot. After construction of ompC and ompU deletion mutants, we found that the agglutinating activity and antibacterial activity of hemocyanin significantly decreased compared to the wild-type strain. After hemocyanin treatment, we identified four intracellular proteins of V. parahaemolyticus, including fructose-bisphosphate aldolase and ribosomal proteins could interact with rOmpC and rOmpU, respectively. Furthermore, we found that the mRNA levels of ompC, ompU, fbaA, rpsB and rpsC significantly decreased after hemocyanin treatment. These findings indicated that OmpC and OmpU are the key targets for L. vannamei hemocyanin recognize pathogens and exert its antibacterial activity.

The evolutionary adaptation of shrimp hemocyanin subtypes and the consequences on their structure and functions

Hemocyanin is the main respiratory protein of arthropods and is formed by hexameric and/or oligomeric subunits. Due to changes in the living environment and gene rearrangement, various hemocyanin subtypes and subunits evolved in crustaceans. This paper reviews the various hemocyanin subtypes and isoforms in shrimp and analyses published genomic data of sixteen hemocyanin family genes from Litopenaeus vannamei to explore the evolution of hemocyanin genes, subunits, and protein structure. Analysis of hemocyanin subtypes distribution and structure in various tissues was also performed and related to multiple and tissue-specific functions, i.e., immunological activity, immune signaling, phenoloxidase activity, modulation of microbiota homeostasis, and energy metabolism. The functional diversity of shrimp hemocyanin due to molecular polymorphism, transcriptional regulation, alternative splicing, degradation into functional peptides, interaction with other proteins or genes, and structural differences will also be highlighted for future research. Inferences would be drawn from other crustaceans to explain how evolution has changed the structure-function of hemocyanin and its implication for evolutionary research into the multifunctionality of hemocyanin and other related proteins in shrimp.

The environmental pollutant BDE-47 modulates immune responses in invitro and in vivo murine models

2,2',4,4'-tetra-bromodiphenyl ether (BDE-47) is widespread in the environment and biological samples. Its association with health risks is an increasing concern, yet information on BDE-47 immunotoxicity remains limited. This study investigated the impact of BDE-47 on innate and adaptive immune responses through in vitro and in vivo approaches. BDE-47's capacity to directly induce cell responses and modulate responses induced by known stimuli was studied in vitro using the RAW 264.7 murine macrophage cell line and spleen-derived lymphocytes, and in vivo using keyhole limpet hemocyanin (KLH)-immunized BALB/c mice orally administered (28 d) at dose levels (7.5, 15.0 and 30 mg/kg/bw/d) derived from relevant toxicokinetic data from rodent models. RAW 264.7 cells stimulated with lipopolysaccharide (LPS) and exposed to BDE-47 exhibited unchanged cell viability but decreased release of interleukin (IL)-6. Primary splenocytes from naïve mice stimulated with anti-CD3/anti-CD28 antibodies and exposed to BDE-47 showed a significant decrease of IL-17 A and IFNγ production. In vivo data showed that BDE-47 significantly reduced the KLH-specific antibody response. A generally decreasing trend of IFNγ, IL-10 and IL-5 production was observed after in vitro antigen-specific restimulation of spleen cells. Histopathological effects on liver, spleen, small intestine and thyroid were detected at the highest dose in the absence of general toxicity. In addition, the expression of Mm_mir155 and Mm_let7a was induced in livers of exposed mice. The data obtained in this study suggest that exposure to BDE-47 may perturb innate and adaptive immune responses, thus possibly decreasing resistance to bacterial and viral infections.

The Yin Yang 1 of Penaeus vannamei regulates transcription of the small subunit hemocyanin gene during Vibrio parahaemolyticus infection

Hemocyanin is a respiratory protein, it is also a multifunctional immune molecule that plays a vital role against pathogen invasion in shrimp. However, the regulation of hemocyanin gene expression in shrimp hemocytes and the mechanisms involved during pathogen infection remains unclear. Here, we used DNA pull-down followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify the Yin Yang 1 transcription factor homolog in Penaeus vannamei (PvYY1) as a key factor that modulates transcription of the small subunit hemocyanin gene of P. vannamei (PvHMCs) in hemocytes during Vibrio parahaemolyticus AHPND (VPAHPND) infection. Bioinformatics analysis revealed that the core promoter region of PvHMCs contains two YY1 motifs. Mutational and oligoprecipitation analyses confirmed that PvYY1 could bind to the YY1 motifs in the PvHMCs core promoter region, while truncation of PvYY1 revealed that the N-terminal domain of PvYY1 is essential for the transactivation of PvHMCs core promoter. Besides, the REPO domain of PvYY1 could repress the activity of the PvHMCs core promoter. Overexpression of PvYY1 significantly activates the promoter activity of PvHMCs core promoter, while PvYY1 knockdown significantly decreases the expression level of PvHMCs in shrimp hemocytes and survival rate of shrimp upon infection with VPAHPND. Our present study provides new insights into the transcriptional regulation of PvHMCs by PvYY1 in shrimp hemocytes during bacteria (VPAHPND) infection.

Methods for Analysis of Nanoparticle Immunosuppressive Properties

Adverse drug effects on immune system function represent a significant concern in the pharmaceutical industry, because 10-20% of drug withdrawal from the market is attributed to immunotoxicity. Immunosuppression is one such adverse effect. The traditional immune function test used to estimate materials' immunosuppression is T cell dependent antibody response (TDAR). This method involves a 28-day in vivo study evaluating the animal's antibody titer to a known antigen (Keyhole Limpet Hemocyanin; KLH) with and without challenge. Due to the limited quantities of novel drug candidates, an in vitro method called human lymphocyte activation (HuLA) assay has been developed to substitute the traditional TDAR assay during early preclinical development. In this test, leukocytes isolated from healthy donors vaccinated with the current year's flu vaccine are incubated with Fluzone in the presence or absence of nanoparticles. The antigen-specific lymphocyte proliferation is then measured by ELISA analyzing incorporation of BrdU into DNA of the proliferating cells. Here we describe the experimental procedures for investigating immunosuppressive properties of nanoparticles by both TDAR and HuLA assays, discuss the in vitro-in vivo correlation of these methods, and show a case study using the iron oxide nanoparticle formulation, Feraheme.

Hemocyanin as a biological indicator of artificial light at night stress in sandy beach amphipods

The influence of artificial light at night (ALAN) is becoming evident in marine sandy beaches. These habitats are dominated by species reliant on natural daylight/night regimes, making the identification of biological indicators a priority. We assessed the applicability of hemocyanin, an oxygen-transport protein in the hemolymph of many invertebrates, as an indicator of ALAN-related stress. Unlike total proteins, hemocyanins signal metabolic function and stress, so we expected them to increase in response to ALAN. We adapted spectrophotometry protocols to describe spatial variation in hemocyanins and total proteins in four populations of the talitroid amphipod Americorchestia longicornis. Then, a two-week experiment tested for changes in response to ALAN. Hemocyanin levels increased by 17 % and 40 % with respect to experimental controls after 7 and 14 d, respectively, and were higher than any measurements conducted in the field. These results suggest good prospects for hemocyanin as an indicator of ALAN effects.

Immunological and biochemical changes in Pacific white shrimp, Litopenaeus vannamei, challenged with Vibrioparahaemolyticus

Vibrio parahaemolyticus (Vpara) is the causative agent of Acute Hepatopancreatic Necrosis Disease (AHPND), or Early Mortality Syndrome (EMS) in shrimp. Shrimp, like other invertebrates, lack an adaptive immune system and depend solely on innate immunity against invading pathogens. To better understand the defense mechanisms of shrimp to this problematic pathogen, we evaluated the changes in hematology, immunology and biochemical values of the hemolymph from shrimp challenged with V. parahaemolyticus up to 8 days post-challenge. Thirty-six shrimp (12 g) were distributed in 9 tanks (75 L), divided into three groups (non-challenged, challenged with 5 × 10² cfu/shrimp and challenged with 1 × 10³ cfu/shrimp) in triplicate. Pacific white shrimp, Litopenaeus vannamei, were administered an inoculum of V. parahaemolyticus under the shell between the 5th and 6th abdominal segment to assess cellular and humoral immune responses. Total hemocyte count (THC) significantly decreased in shrimp challenged with Vpara at 6 h, 12 h and 24 h-post infection. Hemocyte lysate phenoloxidase (PO) activity in Vpara-challenged shrimp at 48 h post challenge was significantly increased compared to that of control shrimp. No significant differences were observed in total plasma protein between plasma from control and Vpara-challenged shrimp. However, shrimp challenged with 5 × 10^2, and 1 × 10³ cfu/shrimp had significantly lower hemocyanin at 6 h and 48 h sampling point, respectively. At 24 h post-challenge, the ≥140 kDa and 70 kDa bands from SDS-PAGE of hemocyanin-concentrated hemolymph lysate samples showed a higher and lower intensity, respectively, in Vpara-challenged group than those of the control group. Plasma from Vpara-challenged shrimp at 6 h and 12 h-post infection significantly suppressed V. parahaemolyticus growth. However, significantly less bacterial growth suppression was observed in plasma of shrimp challenged with higher dose compared to control shrimp at the 192 h post-challenge point. Plasma chemistry parameters did not significantly differ among treatments. The changes observed in hemolymph parameters may be useful indicators of the health status of shrimp.

Structure-Function Relationships of Oxygen Transport Proteins in Marine Invertebrates Enduring Higher Temperatures and Deoxygenation

AbstractPredictions for climate change-to lesser and greater extents-reveal a common scenario in which marine waters are characterized by a deadly trio of stressors: higher temperatures, lower oxygen levels, and acidification. Ectothermic taxa that inhabit coastal waters, such as shellfish, are vulnerable to rapid and prolonged environmental disturbances, such as heatwaves, pollution-induced eutrophication, and dysoxia. Oxygen transport capacity of the hemolymph (blood equivalent) is considered the proximal driver of thermotolerance and respiration in many invertebrates. Moreover, maintaining homeostasis under environmental duress is inextricably linked to the activities of the hemolymph-based oxygen transport or binding proteins. Several protein groups fulfill this role in marine invertebrates: copper-based extracellular hemocyanins, iron-based intracellular hemoglobins and hemerythrins, and giant extracellular hemoglobins. In this brief text, we revisit the distribution and multifunctional properties of oxygen transport proteins, notably hemocyanins, in the context of climate change, and the consequent physiological reprogramming of marine invertebrates.

Deacetylation of K481 and K484 on Penaeid Shrimp Hemocyanin Is Critical for Antibacterial Activity

Although invertebrates' innate immunity relies on several immune-like molecules, the diversity of these molecules and their immune response mechanisms are not well understood. Here, we show that Penaeus vannamei hemocyanin (PvHMC) undergoes specific deacetylation under Vibrio parahaemolyticus and LPS challenge. In vitro deacetylation of PvHMC increases its binding capacity with LPS and antibacterial activity against Gram-negative bacteria. Lysine residues K481 and K484 on the Ig-like domain of PvHMC are the main acetylation sites modulated by the acetyltransferase TIP60 and deacetylase HDAC3. Deacetylation of PvHMC on K481 and K484 allows PvHMC to form a positively charged binding pocket that interacts directly with LPS, whereas acetylation abrogates the positive charge to decrease PvHMC-LPS attraction. Besides, V. parahaemolyticus and LPS challenge increases the expression of Pvhdac3 to induce PvHMC deacetylation. This work indicates that, during bacterial infections, deacetylation of hemocyanin is crucial for binding with LPS to clear Gram-negative bacteria in crustaceans.

Molecular dating of the blood pigment hemocyanin provides new insight into the origin of animals

The Neoproterozoic included changes in oceanic redox conditions, the configuration of continents and climate, extreme ice ages (Sturtian and Marinoan), and the rise of complex life forms. A much-debated topic in geobiology concerns the influence of atmospheric oxygenation on Earth and the origin and diversification of animal lineages, with the most widely popularized hypotheses relying on causal links between oxygen levels and the rise of animals. The vast majority of extant animals use aerobic metabolism for growth and homeostasis; hence, the binding and transportation of oxygen represent a vital physiological task. Considering the blood pigment hemocyanin (Hc) is present in sponges and ctenophores, and likely to be present in the common ancestor of animals, we investigated the evolution and date of Hc emergence using bioinformatics approaches on both transcriptomic and genomic data. Bayesian molecular dating suggested that the ancestral animal Hc gene arose approximately 881 Ma during the Tonian Period (1000-720 Ma), prior to the extreme glaciation events of the Cryogenian Period (720-635 Ma). This result is corroborated by a recently discovered fossil of a putative sponge ~890 Ma and modern molecular dating for the origin of metazoans of ~1,000-650 Ma (but does contradict previous inferences regarding the origin of Hc ~700-600 Ma). Our data reveal that crown-group animals already possessed hemocyanin-like blood pigments, which may have enhanced the oxygen-carrying capacity of these animals in hypoxic environments at that time or acted in the transport of hormones, detoxification of heavy metals, and immunity pathways.

Copper isotope composition of hemocyanin

BACKGROUND

Copper is a metal that plays a central role in biology, for example, as co-factor in various redox enzymes. Its stable isotopic composition is being used as tracer of its transport in living organisms and as a biomarker for diseases affecting its homeostasis. While the application of copper stable isotopes to biological studies is a growing field, there are presently no biological standards that are systematically analyzed in the different laboratories, as it is the case for geological samples (e.g., by using widely available basalt samples). It is therefore paramount for the community to establish such standard. Copper also binds oxygen in the respiratory protein, hemocyanin, in the hemolymph of mollusks and arthropods and is thus critical to respiration for these species.

METHODS

Here, the Cu isotope composition of hemocyanin of different modern species of mollusks and arthropods (Megathura crenulate Keyhole limpet, Limulus polyphemus Horseshoe crab and Concholepas concholepas Chilean abalone), as well as theoretical constraints on the origin of these isotopic fractionations through ab initio calculations are reported.

RESULTS

The isotopic fractionation factors for Cu(I) and Cu(II), both in hemocyanin and in seawater, predict an enrichment in the lighter isotope of Cu in the hemocyanin by over 1 permil compared to seawater. The hemocyanin of Chilean abalone and Horseshoe crab have Cu isotope compositions (δ65Cu = +0.63 ± 0.04‰ and +0.61 ± 0.04‰, respectively, with δ65Cu the permil deviation of the 65Cu/63Cu ratio from the NIST SRM 976 standard), similar to that of the octopus reported in literature (+0.62‰), that are undistinguishable from seawater, suggesting quantitative Cu absorption for these organisms. Conversely, the Keyhole limpet is enriched in the lighter isotope of Cu, which is in line with the ab initio calculation and therefore Cu isotopic fractionation during incorporation of Cu into the hemocyanin.

CONCLUSIONS

Because these hemocyanin standard samples are widely available, they could serve in the future as inter-laboratory standards to verify the accuracy of the Cu isotopic measurements on biological matrices.

Hemocyanins of Muricidae: New 'Insights' Unravel an Additional Highly Hydrophilic 800 kDa Mass Within the Molecule

Hemocyanins are giant oxygen transport proteins that freely float within the hemolymph of most molluscs. The basic quaternary structure of molluscan hemocyanins is a cylindrical decamer with a diameter of 35 nm which is built of 400 kDa subunits. Previously published results, however, showed that one out of two hemocyanin subunits of Rapana venosa encompasses two polypeptides, one 300 kDa and one 100 kDa polypeptide which aggregate to typical 4 MDa and 8 MDa hemocyanin (di-)decamer molecules. It was shown that the polypeptides are bound most probably by one or more cysteine disulfide bridges but it remained open if these polypeptides were coded by one or two genes. Our here presented results clearly showed that both polypeptides are coded by one gene only and that this phenomenon can also be found in the gastropod Nucella lapillus. Thus, it can be defined as clade-specific for Muricidae, a group of the very diverse Caenogastropoda. In addition, we discovered a further deviation of this hemocyanin subunit within both species, namely a region of 340 mainly hydrophilic amino acids (especially histidines and aspartic acids) which have not been identified in any other molluscan hemocyanin, yet. Our results indicate that, within the quaternary structure, these additional amino acids most probably protrude within the inner part of didecamer cylinders, forming a large extra mass of up to 800 kDa. They presumably influence the structure of the protein and may affect the functionality. Thus, these findings reveal further insights into the evolution and structures of gastropod hemocyanins.

The Role of Adjuvants in the Efficacy of a Peptide Vaccine for Myasthenia Gravis

Myasthenia gravis (MG) and its animal model, experimental autoimmune (EA) MG, are caused by interference with neuromuscular transmission by autoantibodies against the nicotinic acetylcholine receptor (AChR) on muscle. Previously, we have shown that two peptides, denoted RhCA 67-16 and RhCA 611-001, designed to be complementary in structure to the main immunogenic region and the dominant Lewis rat T cell epitope (α-chain residues 100-116) of the AChR, respectively, are effective vaccines that prevent EAMG in rats by inducing anti-idiotypic/clonotypic antibodies (Ab) and lowering levels of AChR Ab. These studies employed keyhole limpet hemocyanin (KLH) as a carrier and complete Freunds adjuvant (CFA). In advance of a clinical trial the present study tested the efficacy of RhCA 611-001 when combined with different adjuvants that are approved for use in humans. Adjuvants chosen for comparison were incomplete Freunds adjuvant (IFA) and aluminum hydroxide (Alum). As a second goal we evaluated diphtheria toxin (DT) as an alternative carrier protein to KLH. Alum was found to be an effective adjuvant, particularly when used with the peptide conjugated to DT. This combination of carrier and adjuvant provided protection against EAMG comparable with that observed with CFA and KLH. Using enzyme-linked immunosorbent assays for Ab against RhCA 611-001, it was found that disease protection is qualitatively, but not quantitatively, related to the anti-peptide Ab response. Our results demonstrate a vaccine formulation that should be useful in the first soon-to-be-conducted clinical trials of peptide vaccines to specifically correct aberrant T and B cell responses in an autoimmune disease.

Comparative studies of hemolymph physiology response and HIF-1 expression in different strains of Litopenaeus vannamei under acute hypoxia

Litopenaeus vannamei has a high commercial value and is the primary cultured shellfish species globally. In this study, we have compared the hemolymph physiological responses between two L. vannamei strains under acute hypoxia. The results showed that hemocyanin concentration (HC) of strain A6410 was significantly higher than strain Zhengda; Total hemocyte counts (THC) decreased significantly in both strains under hypoxic stress (p < 0.05). We also investigated the temporal and spatial variations of hypoxia inducible factors 1 (HIF-1) by qRT-PCR. The results showed that hypoxia for 12 h increased the expression levels of HIF-1α in tissues of muscle and gill from the two strains (p < 0.05). In the hepatopancreas, the expression levels of HIF-1 increased significantly in strain Zhengda and decreased significantly in strain A6410 (p < 0.05). No significant changes of HIF-1 expression were detected in the same tissues between the two strains under hypoxia for 6 h (p > 0.05), but in the gills and hepatopancreas under hypoxia for 12 h (p < 0.05). Additionally, the expression level of HIF-1 was higher in the strain Zhengda than A6410 in the same tissue under hypoxia for 12 h. It was indicated that the hypoxic tolerance of Litopenaeus vannamei was closely correlated with the expression level of HIF-1, and the higher expression level of HIF-1 to hypoxia, the lower tolerance to hypoxia in the early stage of hypoxia. These results can help to better understand the molecular mechanisms of hypoxic tolerance and speed up the selective breeding process of hypoxia tolerance in L. vannamei.

Selection based on indirect genetic effects for growth, environmental enrichment and coping style affect the immune status of pigs

Pigs living in intensive husbandry systems may experience both acute and chronic stress through standard management procedures and limitations in their physical and social environment, which may have implications for their immune status. Here, the effect of a new breeding method where pigs were selected on their heritable influence on their pen mates' growth, and environmental enrichment on the immune status of pigs was investigated. Hereto, 240 pigs with a relatively positive genetic effect on the growth of their pen mates (+SBV) and 240 pigs with a relatively negative genetic effect on the growth of their pen mates (-SBV) were housed in barren or straw-enriched pens from 4 to 23 weeks of age (n  =  80 pens in total). A blood sample was taken from the pigs before, three days after a 24 h regrouping test, and at week 22. In addition, effects of coping style, as assessed in a backtest, and gender were also investigated. Mainly, +SBV were found to have lower leukocyte, lymphocyte and haptoglobin concentrations than -SBV pigs. Enriched housed pigs had a lower neutrophil to lymphocyte (N:L) ratio and lower haptoglobin concentrations, but had higher antibody titers specific for Keyhole Limpet Hemocyanin (KLH) than barren housed pigs. No interactions were found between SBV class and housing. Furthermore, pigs with a proactive coping style had higher alternative complement activity and, in the enriched pens, higher antibody titers specific for KLH than pigs with a reactive coping style. Lastly, females tended to have lower leukocyte, but higher haptoglobin concentrations than castrated males. Overall, these results suggest that +SBV pigs and enriched housed pigs were less affected by stress than -SBV and barren housed pigs, respectively. Moreover, immune activation might be differently organized in individuals with different coping styles and to a lesser extent in individuals of opposite genders.

Low-dose temozolomide before dendritic-cell vaccination reduces (specifically) CD4+CD25++Foxp3+ regulatory T-cells in advanced melanoma patients

BACKGROUND

In cancer immunotherapy, dendritic cells (DCs) play a fundamental role in the dialog between innate and adaptive immune response, but several immunosuppressive mechanisms remain to be overcome. For example, a high number of CD4+CD25++Foxp3+ regulatory T-cells (Foxp3+Tregs) have been observed in the peripheral blood and tumor microenvironment of cancer patients. On the basis of this, we conducted a study on DC-based vaccination in advanced melanoma, adding low-dose temozolomide to obtain lymphodepletion.

METHODS

Twenty-one patients were entered onto our vaccination protocol using autologous DCs pulsed with autologous tumor lysate and keyhole limpet hemocyanin. Patients received low-dose temozolomide before vaccination and 5 days of low-dose interleukin-2 (IL-2) after vaccination. Circulating Foxp3+Tregs were evaluated before and after temozolomide, and after IL-2.

RESULTS

Among the 17 evaluable patients we observed 1 partial response (PR), 6 stable disease (SD) and 10 progressive disease (PD). The disease control rate (PR+SD = DCR) was 41% and median overall survival was 10 months. Temozolomide reduced circulating Foxp3+Treg cells in all patients. A statistically significant reduction of 60% was observed in Foxp3+Tregs after the first cycle, whereas the absolute lymphocyte count decreased by only 14%. Conversely, IL-2 increased Foxp3+Treg cell count by 75.4%. Of note the effect of this cytokine, albeit not statistically significant, on the DCR subgroup led to a further 33.8% reduction in Foxp3+Treg cells.

CONCLUSIONS

Our results suggest that the combined immunological therapy, at least as far as the DCR subgroup is concerned, effectively reduced the number of Foxp3+Treg cells, which exerted a blunting effect on the growth-stimulating effect of IL-2. However, this regimen, with its current modality, would not seem to be capable of improving clinical outcome.

[Bioinformatics of mouse uteroglobin binding protein and its polyclonal antibody preparation]

To prepare anti-mouse uteroglobin binding protein (mUGBP) polyclonal antibody, two polypeptides were synthesized based on the bioinformatics analysis of mUGBP, and New Zealand white rabbits were immunized separately with each peptide coupled with keyhole limpet hemocyanin (KLH). The data indicate that a 13-amino acid polypeptide (positions 221st-233rd) was able to generate anti-peptide antibodies. The titer of the antisera detected with ELISA was 1:10(8). The antisera were then purified with immuno-affinity chromatography to obtain antibodies. Western blot analysis of mUGBP expressed as a fusion protein with a green fluorescent protein (GFP) was performed on the cell lysates of COS-1 cells with the purified antisera, suggesting that the antisera specifically recognized UGBP. By immunohistochemistry and indirect immunofluorescence analysis, we examined the expression of UGBP in the lung tissues from a patient undergoing surgical lung resection for a tumor and from normal mouse lung tissue, and found for the first time that UGBP protein was widely expressed in both mouse and human lung tissue with the most abundant expression in bronchial epithelial cells. These results suggest that the antigen epitopes of mUGBP are well predicted by using bioinformatics analysis. We have obtained anti-mUGBP polyclonal antibody, which will be useful for further investigation.

Sensitive enzyme-linked immunosorbent assay and rapid one-step immunochromatographic strip for fumonisin B1 in grain-based food and feed samples

BACKGROUND

Maize contaminated with mycotoxin fumonisin B1 poses a global threat to agricultural production. In this study, polyclonal antibodies (pAb) specific to fumonisin B1 were generated from rabbits immunised with fumonisin B1-keyhole limpet haemocyanin (KLH). These antibodies were used to establish a sensitive competitive direct enzyme-linked immunosorbent assay (cdELISA) and gold nanoparticle immunochromatographic strip for detecting fumonisin B1 levels in maize-based foods and feeds.

RESULTS

In cdELISA, fumonisins B1, B2 and B3 at concentrations of 0.42, 0.58 and 81.5 ng mL(-1) respectively caused 50% inhibition (IC(50)) of binding of fumonisin B1-horseradish peroxidase (HRP) to the antibodies. Effective on-site detection of fumonisin B1 was achieved by developing a rapid and sensitive pAb-based gold nanoparticle immunochromatographic strip. This strip had a detection limit of 5 ng mL(-1) for fumonisin B1 in maize-based samples. Additionally, the whole analytical process could be completed within 10 min. Close examination of 15 maize-based samples by cdELISA revealed that 11 were fumonisin-positive, with a mean concentration of 435 +/- 20.1 ng g(-1). These results correlated well with those obtained by immunochromatographic strip.

CONCLUSION

Both cdELISA and immunochromatographic strip methods established in this study are sensitive for rapid detection of fumonisins in agricultural commodities.

Adjuvant Effects of Aluminum Silicate on IgE and IgG1 Antibody Production in Mice

The adjuvant effects of aluminum silicate on IgE and IgG1 antibody production were investigated. BALB/c mice were immunized intraperitoneally with 10 micrograms ovalbumin (OA) adsorbed on 0.2, 2, or 20 mg aluminum silicate. The enhancement of anti-OA IgE antibody production was observed in the mice injected with aluminum silicate and antigen compared with the mice injected with antigen alone. Anti-OA IgE antibody production with 2 and 20 mg aluminum silicate was greater than that with aluminum hydroxide (alum) as an adjuvant. Similar adjuvant effects with 2 mg aluminum silicate or alum were observed in AKR and C57BL/6 mice using 10 micrograms OA, and in BALB/c mice using 2 micrograms DNP-KLH (dinitrophenyl keyhole limpet hemocyanin): IgE antibody production induced by aluminum silicate adjuvant persisted for weeks in these experiments. The enhancement of IgG1 antibody production to OA mixed with aluminum silicate was also demonstrated. However, no difference between aluminum silicate and alum was observed on the IgG1 antibody production.

Schistosomiasis in Swedish travellers to sub-Saharan Africa: can we rely on serology?

In the absence of egg excretion, laboratory diagnosis of recently acquired schistosomiasis is dependent on serology. 42 of 83 Swedish adventure tourists to sub-Saharan Africa had serum anti-schistosome antibodies indicating recent infection. There is little doubt regarding the specificity and sensitivity of serology for the demonstration of infection, but there is a need for alternative serological methods which could be more widely used than the standard immunofluorescence assay (IFA) for antibodies against gut-derived antigens (anti-GAA). We present results suggesting that 40/42 anti-GAA positive cases also react with keyhole limpet haemocyanin (KLH), a readily available commercial antigen. High anti-GAA titres were seen for more than 2 y despite treatment with praziquantel. Thus we are faced with several questions. How likely is it that positive serology means treatment failure? What is the risk involved in chronic infection? What is the prospect for monitoring treatment outcome by serology? We conclude that there is a need for better information on the risk of becoming infected, for improved methods for testing and for monitoring the therapeutic effects in adventure tourists.

Preparation of specific monoclonal antibodies (MAbs) against heavy metals: MAbs that recognize chelated cadmium ions

Monoclonal antibodies (MAbs) were produced against chelated Cd (2+). Since Cd (2+) ions are too small to elicit an immune response, the metal was coupled to protein carrier (keyhole limpet hemocyanin, KLH) using a bifunctional chelator 1-(4-isothiocyanobenzyl)ethylenediamine N, N, N', N'-tetraacetic acid (ITCBE). Several mice were immunized with this Cd (2+)-ITCBE-KLH immunoconjugate. Spleen cells of two immunized mice were fused with myeloma cells, and the resulting hybridomas were screened using protein conjugates with covalently bound metal-free ITCBE (ethylenediamine tetraacetic acid) or Cd (2+)-ITCBE. Four hybridoma cell lines that produced MAbs with high selectivity and sensitivity (Aa4, Aa6, Ac4, and Ba2) were expanded for further study. Cross-reactivities with other metals were below 1% except for Hg (2+), which showed a slight cross-reactivity in competitive ELISA. These antibodies were used to construct competitive ELISAs for ionic cadmium; the IC 50 of the four antibodies (Aa4, Aa6, Ac4, and Ba2) were 10.59, 4.19, 29.45, and 6.63 microg/L, respectively. The detection range and the lowest detection limit for cadmium, using the Aa6 antibody, were 2.19-86.38 microg/L and 0.313 microg/L, respectively. Spike-recovery studies in tap and stream water showed that the most sensitive antibody can be used for cadmium detection in drinking water.

Mycoplasma hyopneumoniae bacterins and porcine circovirus type 2 (PCV2) infection: induction of postweaning multisystemic wasting syndrome (PMWS) in the gnotobiotic swine model of PCV2-associated disease

Groups (5 to 15 per group) of gnotobiotic swine were infected oronasally with porcine circovirus type 2 (PCV2) at 3 days of age and then given 1 of 6 different commercial Mycoplasma hyopneumoniae (M. hyopneumoniae) bacterins as either a single dose (7 d of age, 1 application products) or 2 doses (7 and 21 d of age, 2 application product). Control groups received PCV2 alone (n = 9) or were infected with PCV2 and immunized twice with keyhole limpet hemocyanin (KLH) emulsified in incomplete Freund's adjuvant (ICFA) (n = 7). Five of 7 (71%) PCV2-infected piglets immunized with KLH/ICFA developed mild or overt PMWS, whereas none of 9 piglets infected with PCV2 alone developed PMWS. Five of 12 (42%) piglets vaccinated with a commercial bacterin containing mineral oil adjuvant developed PMWS following vaccination. None of the PCV2-infected piglets in the other bacterin-vaccinated groups developed PMWS in this model of PCV2-associated disease. This difference in prevalence of PMWS in piglets given the mineral oil-adjuvanted M. hyopneumoniae bacterin and the other M. hyopneumoniae bacterin vaccination groups was statistically significant (P < 0.05).

Effect of inhibitor of tumor necrosis factor-alpha and oxatomide on immune mediated otitis media

OBJECTIVE

Inflammatory mediators (IMs) play a major role in the production of middle ear effusion (MEE). Tumor necrosis factor (TNF)-alpha and leukotrienes (LTs) appear to be important in the pathogenesis of otitis media with effusion (OME). The purpose of this study is to determine the effect of TNF-alpha and LT antagonist on the outcome of experimental immune-mediated OME.

STUDY DESIGN

Prospective.

METHODS

Otitis media was induced in rats by injecting keyhole limpet hemocyanin (KLH) transtympanically 7 days after systemic immunization. Experimental groups were treated with soluble TNF receptor type I (sTNF RI) or oxatomide simultaneously. Seventy-two hours after transtympanic injection, MEE was aspirated, and temporal bone was taken. Vascular permeability (VP) of the middle ear mucosa was measured using the Evans blue dye technique. Hematoxylin-eosin stain and immunohistochemical stain for leukocyte common antigen was performed.

RESULTS

In KLH, sTNF RI, and oxatomide groups, MEE was developed in 83%, 0%, and 66% of the ears, respectively. The sTNF RI group showed significant decrease in effusion production, inflammation, mucosal thickening, and VP compared with the KLH group. These parameters were less significant in the oxatomide group than in the sTNF RI group.

CONCLUSION

Transtympanic administration of sTNF RI and oxatomide appears to suppress the development of immune-mediated MEE.

Phase II trial of idiotype vaccination in previously treated patients with indolent non-Hodgkin's lymphoma resulting in durable clinical responses

PURPOSE

To evaluate idiotype (Id) vaccination as a single agent in previously treated patients with indolent non-Hodgkin's lymphoma.

PATIENTS AND METHODS

Patients underwent biopsy for determination of their lymphoma-specific Id sequence. Recombinant Id protein was manufactured and covalently linked with keyhole limpet hemocyanin (KLH) to generate Id/KLH. Patients received Id/KLH 1 mg on day 1 subcutaneously, with granulocyte-macrophage colony-stimulating factor 250 mug on days 1 to 4, monthly for 6 months. Booster injections were administered until progression. Both clinical and immune responses were evaluated.

RESULTS

Thirty-two previously treated patients received at least one injection of Id/KLH, and 31 were assessed for efficacy. Responses were observed in four patients (one complete response and three partial responses). Median time to onset of response was 5.9 months (range, 2.3 to 14.1 months). Median duration of response has not been reached but should be at least 19.4 months (range, 10.4 to 27.2+ months). Median time to progression is 13.5 months. The most common adverse events were mild to moderate injection site reactions. Six (67%) of nine patients tested demonstrated a cellular immune response, and four (20%) of 20 patients demonstrated an antibody response against their Id.

CONCLUSION

This trial demonstrates that Id/KLH alone can induce tumor regression and durable objective responses. Further study of Id/KLH is recommended in other settings where efficacy may be further enhanced as in first-line therapy or after cytoreductive therapy.

Evidence for proteins involved in prophenoloxidase cascade Eisenia fetida earthworms

The prophenoloxidase cascade represents one of the most important defense mechanisms in many invertebrates. Following the recognition of microbial saccharides by pattern recognition molecules, proteinases cleave inactive prophenoloxidase to its active form, phenoloxidase. Phenoloxidase is a key enzyme responsible for the catalysis of the melanization reaction. Final product melanin is involved in wound healing and immune responses. Prophenoloxidase cascade has been widely described in arthropods; data in other invertebrate groups are less frequent. Here we show detectable phenoloxidase activity in 90-kDa fraction of the coelomic fluid of earthworms Eisenia fetida. Amino acid sequencing of peptides from the active fraction revealed a partial homology with invertebrate phenoloxidases and hemocyanins. Moreover, the level of phenoloxidase activity is lower and the activation slower as compared to other invertebrates.

Leptin regulates energetic tradeoffs between body fat and humoural immunity

Mounting an immune response requires a relatively substantial investment of energy and marked reductions in energy availability can suppress immune function and presumably increase disease susceptibility. We have previously demonstrated that a moderate reduction in energy stores via partial surgical lipectomy (LIPx) impairs humoural immunity of Siberian hamsters (Phodopus sungorus). Here we tested the hypothesis that LIPx-induced decreases in immunity are mediated by changes in the adipose tissue hormone leptin. Hamsters received bilateral surgical removal of inguinal white adipose tissue (IWATx) or sham surgeries (Sham). Half the animals in each group received osmotic minipumps containing murine leptin (0.5mulh-1 for 10 days) whereas the remaining animals received minipumps containing vehicle alone; all animals were subsequently challenged with the novel antigen keyhole limpet haemocyanin (KLH). In general, serum leptin and anti-KLH antibodies were significantly correlated with one another with higher levels generally indicating enhanced immunity. In addition, IWATx hamsters had significantly lower serum anti-KLH IgG compared with sham animals. Exogenous leptin, however, attenuated LIPx-induced immune suppression but did not affect humoural immunity in sham animals. These results suggest that reductions in energy availability lead to impairments in humoural immunity and that leptin can serve as a neuroendocrine signal between body fat and immunity regulating humoural immune responses.

Observation of the fast response of a magnetic resonance signal to neuronal activity: a snail ganglia study

We observed the response of a magnetic resonance signal to neuronal activity in dissected snail ganglia to investigate faster responding components than the blood oxygenation level dependent (BOLD) component. To eliminate the BOLD component completely from the magnetic resonance signal, we used dissected snail ganglia which have non-magnetic hemocyanin, other than hemoglobin, as an oxygen carrying protein. To activate the snail ganglia in synchronization with the magnetic resonance signal measurement, we applied 30 Hz electrical stimulation with a pulse width of 2 s to the ganglia just before the 90 degrees RF pulse. The increase of neuronal activity in the snail ganglia after the electrical stimulation was confirmed with extracellular potential recording. The magnetic resonance signal intensity, measured with the volume selection pulse sequence in a 3.0 T MRI, decreased by about 2.97 +/- 1.10% when the ganglia were activated by the electrical stimulation. We think that the MRI signal decrease is partly due to the magnetic field produced by the neuronal current and partly due to the Lorentz force exerted on the neurons when they were firing.

Recombinant, tumour-derived idiotype vaccination for indolent B cell non-Hodgkin’s lymphomas: a focus on FavId™

FavId (Favrille, Inc., San Diego, CA, USA) is a personalized therapeutic vaccine product for B cell non-Hodgkin's lymphoma, custom-manufactured from individual patient's tumour cells. This investigational agent consists of recombinant tumour-specific immunoglobulin (idiotype [Id]) chemically conjugated to the highly immunogenic carrier protein keyhole limpet haemocyanin (Id-KLH). The vaccine product is administered by subcutaneous co-injection with the cytokine adjuvant granulocyte-macrophage colony-stimulating factor (GM-CSF) with the goal of stimulating tumour-specific T cell and humoral immunity. Therapeutic Id vaccines have shown promising results in early phase clinical trials in follicular lymphoma, and several Phase III trials are ongoing. FavId's advantages over other Id vaccine formulations include its rapid and efficient manufacturing technology utilising recombinant baculovirus, with a production time of only 8-12 weeks. In Phase II studies, FavId Id-KLH plus GM-CSF vaccines have been found to be safe, immunogenic and clinically active in follicular lymphoma. At present, FavId is being tested in a randomised, placebo-controlled Phase III trial in follicular lymphoma, aimed at improving the time to disease progression when administered following cytoreduction with rituximab. If found to be efficacious in this pivotal trial, FavId would represent a tumour-selective immunotherapy for lymphoma with little toxicity and a novel mechanism of action.

Cochlear microperfusion: experimental evaluation of a potential new therapy for severe hearing loss caused by inflammation

HYPOTHESIS

Cochlear microperfusion will be a useful treatment of severe sensorineural hearing loss caused by inflammation.

BACKGROUND

Viruses, bacteria, and autoimmunity can initiate inflammation in the inner ear. The acute phase is associated with elevations in cytokines, nitrous oxide, and cellular infiltrates and the breakdown of the blood-labyrinthine barrier. The chronic phase leads to irreversible ossification of the labyrinth.

METHODS

The authors developed cochlear microperfusion to facilitate removal of inflammatory cells and their byproducts during the acute phase of inflammation. Using a ventral approach to the guinea pig cochlea, the authors displaced resident perilymph by delivering perfusate into the scala vestibuli and collecting the effluent from the scala tympani. The authors evaluated the benefit of the procedure in an animal model of severe hearing loss caused by inflammation.

RESULTS

Healthy controls undergoing cochlear microperfusion with phosphate-buffered saline incurred a mean hearing loss of 16 dB (n=4). This hearing loss was associated with the creation of two cochleostomies and not the perfusion itself. Sterile labyrinthitis (n=5) generated by perfusion of the cochlea with antigen consistently produced severe hearing loss over the initial 48 hours, and this hearing loss persisted for the subsequent 7 days. Therapeutic cochlear microperfusion, performed within the first 24 hours of developing severe hearing loss (n=9), immediately restored on average 24 dB (p <0.007) of hearing.

CONCLUSION

Cochlear microperfusion is a promising new technique for treating severe deafness caused by inflammation. The benefit may be sustained when combined with local delivery of immunosuppressive agents to the inner ear.

Defective B cell responses in the absence of SH2D1A

More than half of patients with X-linked lympho-proliferative disease, which is caused by a defect in the intracellular adapter protein SH2D1A, suffer from an extreme susceptibility to Epstein-Barr virus. One-third of these patients, however, develop dysgammaglobulenemia without an episode of severe mononucleosis. Here we show that in SH2D1A(-/-) mice, both primary and secondary responses of all Ig subclasses are severely impaired in response to specific antigens. Because germinal centers were absent in SH2D1A(-/-) mice upon primary immunization, and because SH2D1A was detectable in wt germinal center B cells, we examined whether SH2D1A(-/-) B cell functions were impaired. Using the adoptive cotransfer of B lymphocytes from hapten-primed SH2D1A(-/-) mice with CD4(+) T cells from primed wt mice into irradiated wt mice provided evidence that signal transduction events controlled by SH2D1A are essential for B cell activities resulting in antigen specific IgG production. Defects in naive SH2D1A(-/-) B cells became evident upon cotransfer with non-primed wt CD4(+) cells into Rag2(-/-) recipients. Thus, both defective T and B cells exist in the absence of SH2D1A, which may explain the progressive dysgammaglobulinemia in a subset of X-linked lympho-proliferative disease patients without involvement of Epstein-Barr virus.

Immunoglobulin class switch recombination is impaired in Atm-deficient mice

Immunoglobulin class switch recombination (Ig CSR) involves DNA double strand breaks (DSBs) at recombining switch regions and repair of these breaks by nonhomologous end-joining. Because the protein kinase ataxia telengiectasia (AT) mutated (ATM) plays a critical role in DSB repair and AT patients show abnormalities of Ig isotype expression, we assessed the role of ATM in CSR by examining ATM-deficient mice. In response to T cell–dependent antigen (Ag), Atm^−/− mice secreted substantially less Ag-specific IgA, IgG1, IgG2b, and IgG3, and less total IgE than Atm^+/+ controls. To determine whether Atm^−/− B cells have an intrinsic defect in their ability to undergo CSR, we analyzed in vitro responses of purified B cells. Atm^−/− cells secreted substantially less IgA, IgG1, IgG2a, IgG3, and IgE than wild-type (WT) controls in response to stimulation with lipopolysaccharide, CD40 ligand, or anti-IgD plus appropriate cytokines. Molecular analysis of in vitro responses indicated that WT and Atm^−/− B cells produced equivalent amounts of germline IgG1 and IgE transcripts, whereas Atm^−/− B cells produced markedly reduced productive IgG1 and IgE transcripts. The reduction in isotype switching by Atm^−/− B cells occurs at the level of genomic DNA recombination as measured by digestion–circularization PCR. Analysis of sequences at CSR sites indicated that there is greater microhomology at the μ–γ1 switch junctions in ATM B cells than in wild-type B cells, suggesting that ATM function affects the need or preference for sequence homology in the CSR process. These findings suggest a role of ATM in DNA DSB recognition and/or repair during CSR.

Analysis of T-cell responses in metastatic melanoma patients vaccinated with dendritic cells pulsed with tumor lysates

In melanoma patients, CD8+ cytotoxic T cells have been found recognizing self-proteins of which the expression is restricted to the melanocytic lineage. These melanocyte differentiation antigens are expressed in normal melanocytes as well as in 80-100% of primary and metastatic melanoma. In this report, six HLA-A*0201-subtyped metastatic melanoma patients vaccinated with dendritic cells (DCs) pulsed with autologous tumor lysates and keyhole limpet hemocyanin (KLH) were screened for the presence of CD8+ T cells specific for three HLA-A*0201-binding peptides derived from the melanosomal antigens MART-1/Melan-A, gp100, and tyrosinase. For this purpose, nonstimulated as well as in vitro peptide-stimulated peripheral blood mononuclear cells (PBMCs) were tested for peptide-specific IFN-gamma release by enzyme-linked immunosorbent spot (ELISpot) assays. Furthermore, expression of the melanosomal antigens MART-1/Melan-A, gp100, and tyrosinase in tumor lesions was analyzed by immunohistochemistry before and after vaccination. We also used the ELISpot technique to investigate whether KLH-specific T cells were induced and whether these cells released type 1 (IFN-gamma) and/or type 2 (IL-13) cytokines. Our data show induction of CD8+ T cells specific for the melanosomal peptides MART-1/Melan-A(27-35) or tyrosinase(1-9), as well as IFN-gamma-releasing KLH-specific T cells, in two of six vaccinated melanoma patients, but do not support an association between the induction of these T cells and clinical responses.

Primary immune response to keyhole limpet haemocyanin following trauma in relation to low plasma glutamine

Severe trauma can lead to a compromised immune response, thereby increasing susceptibility to infections. Here we will study to what extent these early changes in the immune status upon trauma affect a primary immune response to keyhole limpet haemocyanin (KLH). Because glutamine is the preferred respiratory substrate for immune competent cells and known to be depleted after trauma, we studied the immune status and the primary sensitization in relation to the glutamine plasma concentration in a group of severe trauma patients [injury severity score (ISS) >17]. Trauma patients (n = 31) were sensitized with KLH within 12 h after trauma; plasma glutamine concentrations and immune parameters were determined, after which KLH-specific immune responsiveness was evaluated on days 9 and 14. Low plasma glutamine concentrations were found after trauma. Significantly elevated numbers of granulocytes and CD14-positive leucocytes were found, whereas the HLA-DR expression on CD14-positive cells was significantly lower in trauma patients than in healthy controls. Trauma did not change the in vitro proliferative capacity of lymphocytes when cultured with glutamine; however, when lymphocytes were cultured without glutamine, trauma resulted in lower proliferation than healthy controls. Phytohaemagglutinin-(PHA)-induced interferon (IFN)-gamma and interleukin (IL)-10 production was significantly lower after trauma, whereas IL-4 production was not affected. KLH sensitization following trauma resulted in poor skin test reactivity and low in vitro KLH-induced lymphocyte proliferation compared to controls. In contrast, the development of anti-KLH IgM, IgG, IgA, IgG1, IgG2, IgG3 and IgG4 production on days 9 and 14 following trauma was not different from that in healthy controls. Major trauma was associated with a reduced cell-mediated immune response, correlating with low plasma glutamine concentrations, while no effects of trauma were found on the development of a primary humoral immune response.

Clostridium difficile toxin A carboxyl-terminus peptide lacking ADP-ribosyltransferase activity acts as a mucosal adjuvant

The receptor binding domains of the most potent mucosal adjuvants, bacterial toxins and plant lectins, are organized in repeat units to recognize specific sugar residues. The lectin-like structure of the C-terminal region of Clostridium difficile toxin A prompted us to investigate the mucosal adjuvant properties of a nontoxigenic peptide corresponding to amino acids 2394 to 2706 (TxA(C314)). We compared TxA(C314) adjuvant activity to those of cholera toxin (CT) and Escherichia coli heat-labile enterotoxin subunit B (EtxB) coadministered orally or nasotracheally with poor peptide antigens (keyhole limpet hemocyanin [KLH] and hen egg lysozyme [HEL]). Levels of anti-KLH-specific serum immunoglobulin G (IgG) and IgA as well as that of mucosal IgA were significantly higher in animals immunized orally with TxA(C314) plus KLH than with KLH alone, CT plus KLH, or EtxB plus KLH. Following intranasal immunization with TxA(C314) plus HEL, levels of serum- and mucosa-specific antibodies were comparable to those induced by coadministering HEL with CT or EtxB. The TxA(C314) adjuvant effect following oral, but not intranasal, immunization was dose dependent. The analysis of the subclasses of anti-KLH-specific IgG isotypes and the cytokines released from splenocytes of immunized mice challenged in vitro with KLH indicates the induction of a mixed Th1/Th2-type immune response, with prevalence of the Th1 branch. We conclude that TxA(C314) enhances immune responses against mucosa-coadministered foreign antigens and represents a promising mucosal adjuvant, especially because its ability to stimulate mixed Th1/Th2 responses with a strong a Th1 component is extremely worthwhile against intracellular pathogens.

Vaccine therapy for small cell lung cancer

One novel approach to the treatment of lethal residual disease in patients with small cell lung cancer (SCLC) relies on the induction of a host-immune response to attack chemoresistant tumor cells. Because of its neuroectodermal origin, SCLC has a number of specific antigens that could be capitalized on as immune targets. This article reviews two vaccine strategies currently in clinical study. The anti-idiotype vaccine to the GD3 ganglioside, BEC-2, has recently been tested in a phase III trial. In this trial, patients with SCLC who had completed initial chemotherapy were randomized to observation or vaccination with BEC-2 plus bacillus Calmette-Guerin adjuvant. A series of other trials have established the immunogenicity of several keyhole limpet hemocyanin conjugate vaccines relevant to SCLC, including GM2, Globo H, fucosyl GM1, and polysialic acid. To optimize an immune response against a broad range of tumor phenotypes, these components will be combined into a polyvalent vaccine. A randomized phase II trial of this polyvalent vaccine is planned to start in 2004.

Development of an enzyme-linked immunosorbent assay for the detection of the organophosphorus insecticide acephate

A competitive indirect enzyme-linked immunosorbent assay (ciELISA) for the organophosphorus insecticide acephate, O,S-dimethyl acetylphosphoramidothioate, was developed using a polyclonal antibody. Five different haptens mimicking the analyte were synthesized and conjugated with the carrier proteins bovine serum albumin (BSA) and keyhole limpet hemocyanin (KLH) by the N-hydroxysuccinimide active ester and diazotization methods. Polyclonal antibodies raised against hapten-KLH conjugates in rabbits and hapten-BSA conjugates as coating antigens were screened and selected for the assay in the homologous and heterologous ELISA systems. The effects of various assay conditions such as detergent, organic solvents, pH, and preincubation of the mixture of the polyclonal antibody and the analyte on the sensitivity were evaluated. The IC(50) value for acephate was 25 ng/mL in an optimized heterologous system using hapten-4-BSA as a coating antigen and a polyclonal antibody no. 8377 against hapten-1-KLH, showing the detection range of 5-140 ng/mL and the lowest detection limit of 2 ng/mL. The cross-reactivities of the structurally related organophosphorus insecticides, including the major metabolite of the analyte, methamidophos, were less than 1%. Recoveries from the analyte-fortified tap water, mulberry leaves, and lettuce samples in the assay were in the range of 72-121% by simple extraction, concentration, and dilution. These results indicate that the ELISA could be a convenient and supplemental analytical tool for monitoring acephate residues in environmental and agricultural samples.

Translational development of active immunotherapy for hematologic malignancies

Idiotype (Id) antigen is a unique, truly tumor-specific antigen. Early preclinical studies have shown Id vaccination to be efficacious against established tumors, and this effect is enhanced by addition of the cytokine granulocyte-macrophage. One clinical study showed that injections of immunoglobulin derived from each patient's tumor cells (immunoglobulin-Id protein) induced Id-specific immunologic responses of the humoral type and/or the cell-mediated type, and that those patients who experienced cell-mediated responses achieved molecular remissions. Addition of cytokines to Id vaccination can greatly influence the magnitude and phenotype of the immune response to protein antigens. One cytokine, granulocyte-macrophage colony-stimulating factor, is particularly important to the success of cancer immunotherapy. Some studies have shown the ability of granulocyte-macrophage colony-stimulating factor to enhance protective tumor immunity and help prolong survival rates. A number of trials have been conducted on the use of Id vaccination in the treatment of follicular lymphoma. Currently, the National Cancer Institute (Frederick, MD) is conducting a large, randomized, multicenter, phase III trial comparing chemotherapy alone versus chemotherapy followed by vaccination with Id-keyhole limpet hemocyanin plus granulocyte-macrophage colony-stimulating factor. This pivotal study is the final step before vaccine therapy might be considered as an option of standard care for patients with follicular lymphoma.

Active immunization against nicotine suppresses nicotine-induced dopamine release in the rat nucleus accumbens shell

BACKGROUND

Tobacco smoking is the largest preventable cause of morbidity and premature mortality in the world. Although its medical consequences are well documented, 20-50% of the population even in developed countries remain tobacco smokers. The drugs presently used in smoking cessation have limited efficiency and, therefore, there is a need for alternative and improved treatments. One novel approach in this regard may be provided by immunization against nicotine.

OBJECTIVE

The present study in male Wistar rats investigated if active immunization with a novel nicotine immunogen, IP18-KLH, may generate nicotine-selective antibodies and, furthermore, whether this treatment might prevent nicotine from exerting its stimulating effect on the mesolimbic, dopaminergic reward system in the brain.

METHODS

Enzyme-linked immunosorbent assay (ELISA) was used to determine the titer of nicotine antibodies in plasma after immunization with IP18-KLH in Freund's adjuvant. Competitive ELISA was used to assess the selectivity of the antibodies. Finally, we used in vivo voltammetry to investigate whether active immunization with IP18-KLH could prevent nicotine-induced dopamine release in the shell of nucleus accumbens (NAC(shell)).

RESULTS

The present study shows that active immunization with IP18-KLH generates antibodies that are highly selective for nicotine. Furthermore, immunization with IP18-KLH prevented the nicotine-induced increase in dopamine release in the NAC(shell), a biochemical correlate to the rewarding properties of nicotine.

CONCLUSIONS

Active immunization with IP18-KLH prevents a central effect of nicotine that is considered critical for the induction of nicotine dependence. Consequently, active immunization may provide long-term protection against initiation of tobacco dependence, an effect that may prove particularly advantageous in relapse prevention.

Effects of sphingomyelin on aberrant colonic crypt foci development, colon crypt cell proliferation and immune function in an aging rat tumor model

Sphingomyelin (SPM) was assessed in older rats for in vivo effects on multiple immune responses and the development of colon preneoplastic lesions. Fifty-four-week-old rats were injected with 10 mg/kg body weight of the carcinogen azoxymethane (AOM), and then treated with 35 mg/kg body weight SPM orally for 6 weeks beginning 6 weeks after AOM treatment. None of the immune functions tested (antibody formation, delayed-type hypersensitivity or natural killer cell cytotoxicity) were significantly affected by SPM treatment. Natural killer (NK) cell activity was, however, decreased in all rats that were treated with AOM. There was a tendency for decreased aberrant crypt foci (ACF) numbers in the SPM-treated rats but this reduction was only significant for the largest lesions (> nine crypts per foci). The decreased ACF numbers were most evident in the proximal end of the colon. Colonic crypt cell proliferation was also decreased in SPM treated rats. This reduction was primarily in the base of the crypt column. Also, low numbers of ACF developed spontaneously in rats not treated with AOM, but no ACF were present in non-AOM rats that also received SPM. It appears that SPM may have effects on the post-initiation development of preneoplastic lesions in the rat colon but not on the immune functions assessed in this study.

Antigen-specific suppression of a primed immune response by dendritic cells mediated by regulatory T cells secreting interleukin-10

Antigen-specific suppression of a previously primed immune response is a major challenge for immunotherapy of autoimmune disease. RelB activation is required for myeloid DC differentiation. Here, we show that antigen-exposed DCs in which RelB function is inhibited lack cell surface CD40, prevent priming of immunity, and suppress previously primed immune responses. DCs generated from CD40-deficient mice similarly confer suppression. Regulatory CD4+ T cells induced by the DCs transfer antigen-specific "infectious" tolerance to primed recipients in an interleukin-10-dependent fashion. Thus CD40, regulated by RelB activity, determines the consequences of antigen presentation by myeloid DCs. These observations have significance for autoimmune immunotherapy and suggest a mechanism by which peripheral tolerance might be constitutively maintained by RelB(-) CD40(-) DCs.

Preparation and development of anti-chitosan antibodies

Polyclonal antibodies directed against chitosan were produced using several immunogens, prepared by binding the polymer according to two ways (covalent and electrostatic) with a protein (bovine serum albumin or hemocyanin). It appeared that the presence of a carrier protein linked to chitosan was necessary to enhance the immune response and to obtain antibodies in a stable and reproducible way. Direct and inhibition enzyme-linked immunosorbent assay experiments were performed to assess the affinity and the specificity of the antibodies. The interactions of these antibodies with modified chitosans showed no influence of the degree of polymerization of the polymer in the range studied (from 24 to 2261), by contrast with the degree of acetylation. The affinity decreased when the degree of acetylation increased. Absence of cross-reactivity with glycosaminoglycans was observed whatever the antibody. The cationicity of the amine function along the polymer chains may have a role in the immunological recognition of the chitosan structure.

Rapid selection of anti-hapten antibodies isolated from synthetic and semi-synthetic antibody phage display libraries expressed in Escherichia coli

Antibody phage display libraries (Griffin and Tomlinson I) displaying antibody genes and maintained and amplified in Escherichia coli were used to isolate antibodies to the hapten target microcystin LR (1000 Da) conjugated to either bovine serum albumin or keyhole limpet haemocyanin. In competition enzyme-linked immunosorbent assay, bacterially expressed antibodies selected via the Griffin library showed at least 300 times greater sensitivity than those isolated from the Tomlinson library, for free microcystin. Bacterially expressed phage antibody libraries provide a rapid and relatively easy route for the selection of monoclonal antibodies specific for even the most difficult of antigenic targets such as free haptens.

Plasma pentosidine levels measured by a newly developed method using ELISA in patients with chronic renal failure

The plasma pentosidine levels in patients with renal disease were measured by a simple method which was established for plasma and urinary pentosidine determinations. The method, which can be completed within a few hours, involves pretreating plasma with proteolytic enzyme (pronase) and measuring the concentration of pentosidine in the sample by ELISA using antipentosidine antibodies. The prepared antibodies showed no cross-reaction with the raw materials for pentosidine synthesis or with compounds having similar structures. SDS-PAGE indicated that the antibodies had a high purity. The reaction of the antibodies and keyhole limpet hemocyanin-pentosidine in the competitive ELISA system was inhibited by free pentosidine. Excellent standard curves for pentosidine determination were obtained. In actual measurements of clinical samples from patients, a good correlation (r = 0.9356) was obtained between the values measured by ELISA and HPLC. The plasma pentosidine level in patients with renal disease correlated significantly with plasma creatinine, urea nitrogen, beta2-microglobulin, and creatinine clearance, indicating its usefulness in evaluating the severity of renal disease. A significant elevation in plasma pentosidine levels was observed in mild renal dysfunction, whereas no significant increases in creatinine and urea nitrogen levels were detected, suggesting that the plasma pentosidine level is useful in the early diagnosis of beginning renal failure. In patients with chronic renal failure, no difference in plasma pentosidine levels was observed between diabetic nephropathy and chronic glomerulonephritis, while a significant correlation was observed with phosphatidylcholine hydroperoxide, suggesting the possibility that the plasma pentosidine level reflects injury due to oxidation. From these results, the quantitative measurement method developed by us is judged to be a superior innovation for measuring pentosidine in body fluids. The plasma pentosidine level may be useful for the early diagnosis of mild renal failure and to estimate the degree of the severity of renal diseases.

Regression of lymph node metastases by immunotherapy using autologous breast tumor-lysate pulsed dendritic cells: report of a case

A 50-year-old woman was diagnosed as having stage IV breast cancer with bilateral supraclavicular lymph node metastasis resistant to CAF therapy. She received immunotherapy using autologous tumor lysate-pulsed dendritic cells (DCs). Four cycles of DC injection into the right supraclavicular lymph nodes resulted in regression of bilateral supraclavicular lymphogenous metastasis. Histological studies revealed an accumulation of CD45+ T lymphcytes in the regressive lymph nodes. This case suggests that immunotherapy with DCs may be a safe and promising approach for the treatment of advanced breast cancer.

Apoptosis in the hydropic cochlea of guinea pigs following immune reaction of the endolymphatic sac: immunohistochemical analysis

Apoptotic change in the cochlea was studied by immunohistochemistry after the injection of keyhole limpet haemocyanin (KLH) into the right endolymphatic sac of guinea pigs. Apoptosis was examined with the specific antibody to single-stranded DNA (ssDNA). Endolymphatic hydrops became evident in the cochlea 1 day after the injection of KLH (n = 6). Increased ssDNA expression could be detected in the spiral ligament and the stria vascularis. The temporal bones in the control group did not show any ssDNA immunoreactivity (n = 6). Apoptosis is the process of the cell death. Our findings imply that apoptotic changes are involved in endolymphatic hydrops. These phenomena could lead to cochlear dysfunction as seen in endolymphatic hydrops.

Multiple immune functions in rats fed Echinacea extracts

This study evaluated acquired-immune functions representing the three major branches of the immune system in male rats fed a commercially available echinacea product. An additional comparison of effects on antibody formation in male and female rats was done using the commercial echinacea product and two echinacea tinctures marketed by local herbalists. In initial testing, we found no evidence of altered natural killer cell activity, T cell-mediated delayed-type hypersensitivity, or specific antibody formation in male rats given either a 225 mg/kg or 50 mg/kg of the commercial echinacea for 6 weeks. Antibody formation was significantly suppressed in female but not male rats given 250 mg/kg for 2 weeks of the commercial echinacea. The local products tested had no effect on antibody formation. We concluded that our study provided no supporting evidence for immunostimulatory activity by the echinacea preparations we examined and, in fact, may be immunosuppressive under some conditions.