Effective equine immunization protocol for production of potent poly-specific antisera against Calloselasma rhodostoma, Cryptelytrops albolabris and Daboia siamensis

Snake envenomation has been estimated to affect 1.8 million people annually with about 94,000 deaths mostly in poor tropical countries. Specific antivenoms are the only rational and effective therapy for these cases. Efforts are being made to produce effective, affordable and sufficient antivenoms for these victims. The immunization process, which has rarely been described in detail, is one step that needs to be rigorously studied and improved especially with regard to the production of polyspecific antisera. The polyspecific nature of therapeutic antivenom could obviate the need to identify the culprit snake species. The aim of this study was to produce potent polyspecific antisera against 3 medically important vipers of Thailand and its neighboring countries, namely Cryptelytrops albolabris "White lipped pit viper" (CA), Calleoselasma rhodostoma "Malayan pit viper" (CR), and Daboia siamensis "Russell's viper" (DS). Four horses were immunized with a mixture of the 3 viper venoms using the 'low dose, low volume multi-site' immunization protocol. The antisera showed rapid rise in ELISA titers against the 3 venoms and reached plateau at about the 8th week post-immunization. The in vivo neutralization potency (P) of the antisera against CA, CR and DS venoms was 10.40, 2.42 and 0.76 mg/ml, respectively and was much higher than the minimal potency limits set by Queen Soavabha Memorial Institute (QSMI). The corresponding potency values for the QSMI monospecific antisera against CA, CR and DS venoms were 7.28, 3.12 and 1.50 mg/ml, respectively. The polyspecific antisera also effectively neutralized the procoagulant, hemorrhagic, necrotic and nephrotoxic activities of the viper venoms. This effective immunization protocol should be useful in the production of potent polyspecific antisera against snake venoms, and equine antisera against tetanus, diphtheria or rabies.

[Prokaryotic expression of vp3 gene of Muscovy duck parvovirus, and its antiserum preparation for detection of virus multiplication]

New epidemic broke out in recent year which was suspected to be caused by variant Muscovy duck parvovirus (MDPV). For this reason, new MDPV detection methods are needed for the new virus strains. In this study, a pair of primers were designed according to the full-length genome of MDPV strain SAAS-SHNH, which were identified in 2012, and were used to amplify the vp3 gene of MDPV by polymerase chain reaction. After being sequenced, the vp3 gene was subcloned into the prokaryotic expression vector PET28a. The recombinant plasmid was transformed into E. coli BL21 and induced with IPTG. SDS-PAGE and Western blotting analysis showed the MDPV vp3 gene was successfully expressed. After being purified by Ni2+ affinity chromatography system, the recombinant protein was used as antigen to immunize rabbits to obtain antiserum. Western blotting analysis showed that the acquired antiserum could react specifically with VP3 protein of J3D6 strain and MDPV vaccine strain. The antiserum could also be used for detection of cultured MDPV from primary duck embryo fibroblasts by immune fluorescence assay (IFA). It could be concluded that the VP3 protein and its antibody prepared in the research could be used for detection of VP3 antiserum and antigen respectively.

[Expression and purification of HPV16 E2 protein and preparation of its antiserum]

OBJECTIVE

To express and purify the human papillomavirus type 16 (HPV16) E2 protein in prokaryotic bacteria and prepare the antiserum of HPV16 E2.

METHODS

After amplified by PCR, HPV16 E2 was inserted into pET21b vector. The recombinant pET21b-HPV16E2 vector was transfected into E.coli BL21 (DE3). Expression product was identified after induction. Through purification, denaturation and renaturation, soluble protein was obtained. With the HPV16 E2 protein, we immunized BALB/c mice and examined mouse IFN-γ, CD4(+); T cells, CD8(+); T cells, CD4/CD8 ratio and antiserum titer.

RESULTS

Restriction digestion and DNA sequencing showed pET21b-HPV16E2 was constructed successfully. Relative molecular mass (Mr;) of HPV16 E2 was 42 000 in SDS-PAGE and the specificity of the protein was confirmed with Western blotting. The antiserum could specifically bind with HPV16 E2 protein. In the immunized BALB/c mice, antiserum titre, CD4(+); T cell count and CD4/CD8 ratio increased, while mouse IFN-γ did not change obviously.

CONCLUSION

Soluble HPV16 E2 protein was obtained successfully. The antiserum of high titer against HPV16 E2 was prepared in mice.

Indirect homologous competitive enzyme-linked immunosorbent assay for the detection of a class of glycosylated dihydrochalcones

Hesperetin dihydrochalcone 4'-glucoside, 1, and phloretin 4'-glucoside, 2, belong to a family of dihydrochalcone glycosides that exhibit flavorant properties. In this study was developed a competitive, indirect homologous ELISA for the detection of targets 1 and 2 in fermentation media. Immunogen and coating antigen were prepared by conjugating hapten, 4-(3-oxo-3-(2,6-dihydroxy-4-glucoside phenyl)propyl) benzoic acid, to thyroglobulin and bovine serum albumin, respectively. Antibodies raised in rabbits M6122, M6123, and M6124 and the coating antigen were screened and characterized to determine their optimum concentrations. The optimized ELISA, developed with antibody M6122, gave IC50 values of 27.8 and 21.8 ng/mL for 1 and 2, respectively. Selectivity of the assay was assessed by measuring cross-reactivity of antibody M6122 to related congeners such as aglycones and the 2'-glycosides of hesperetin dihydrochalcone, 5 and phloretin, 6. Antibody M6122 showed very low recognition of 5 and virtually no recognition of the aglycones and 6.

[Human CD96 gene cloning, expression and identification]

OBJECTIVE

To construct and express human CD96 gene outer membrane domain (hCD96om) in prokaryotic cells and prepare rabbit polyclonal antibody of hCD96om.

METHODS

hCD96om was amplified by RT-PCR from the peripheral blood of patients with acute myeloid leukemia and inserted into prokaryotic expression vector pET32a(+) to construct the recombinant plasmid pET32-CD96. The expression of hCD96om was induced by IPTG in BL21(DE3) cells, and the expression product was identified by Western blotting. The anti-hCD96 polyclonal antibody was prepared by immunization of rabbits with the fusion protein. The specificity of anti-hCD96 antibody was determined by Western blotting.

RESULTS

hCD96om protein was expressed in E.coli BL21(DE3) cells in the form of inclusion body, with a relative molecular mass around 37 kD. Western blotting showed a specific reaction of the prepared antiserum with the 70 kD protein extracted from human leukemia cell line HL-60 cells and with the 37 kD hCD96om fusion protein.

CONCLUSION

The CD96 gene of human has been successfully cloned and expressed in BL21(DE3) cells, and its rabbit polyclonal antibody has been obtained.

[Evaluation of the efficiency and reactogenicity of emulsion-based adjuvant systems in the manufacture of polyclonal enteroviral diagnostic sera]

Whether various adjuvants might be used in the manufacture of commercial enteroviral diagnostic sera (EDS) was studied. The following adjuvants: Ribi, SAF-1, and TiterMax were compared; vaseline-lanoline emulsion used to prepare EDSs, as well as modified Freund's complete adjuvant served as controls. Chinchilla rabbits were intramuscularly injected enterovirus antigens (enterovirus 70 and ECHO 2) together with the adjuvant emulsions. TiterMax showed the highest efficiency comparable with the activity of Freund's adjuvant. The activities of Ribi, SAF-1, and vaseline-lanoline emulsion were 3-4 times lower. The neutralizing activity of the sera obtained after 2-3 (TiterMax) or 4-5 (Ribi, SAF-1) immunizations was maximal. Further immunizations resulted in a reduction in the titers of neutralizing antibodies. TiterMax and vaseline-lanoline emulsion caused minimal complications at the site of inoculation whereas SAF-1 and Ribi gave rise to severer inflammatory responses.

Characterization of an antiserum against Atlantic cod (Gadus morhua L.) g-type lysozyme

In this study we describe the production and characterization of an antiserum against recombinant g-type lysozyme derived from Atlantic cod. This is also the first initial analyses of g-type lysozyme protein expression in tissues of Atlantic cod. Recombinant expression and purification of cod g-type lysozyme was used for immunization to rabbit and the rabbit sera were analysed for anti g-type lysozyme antibodies using enzyme-linked immunosorbent assay (ELISA), Western blot and immunohistochemistry. ELISA results showed that antibody titres were mounted between 12,800 and 25,600 as measured at an optical density corresponding to 50% of the maximal level. By Western blot analysis the rabbit immune serum detected a single ∼23 kDa band representing the size of the injected antigen, in both spleen and head kidney homogenates from the Atlantic cod. Immunohistochemisrty detected the native folded g-type lysozyme in tissues and revealed that g-type lysozyme positive cells were observed in haematopoietic tissue of the head kidney and in red pulp of spleen. In conclusion, the rabbit anti g-type lysozyme immune sera was developed and is effectively utilized for ELISA, Western analysis as well as for immunohistochemistry. This has allowed us to obtain new knowledge about this protein regarding localization and distribution in cod tissue.

Production and purification of polyclonal antibodies

Polyclonal antibodies are derived from multiple B-cell clones that have differentiated into antibody-producing plasma cells in response to an immunogen. Polyclonal antibodies raised against a single molecular species of antigen recognize multiple epitopes on a target molecule resulting in signal amplification in indirect immunoassays, including immuno-electron microscopy. In this chapter, we present a basic procedure to generate polyclonal antibodies in rabbits.

Use of latex agglutination test to determine rabies antibodies in production of rabies antisera in horses

A therapeutic anti-rabies immunoglobulin for human use has been produced mainly in horses. The presently available seroneutralization test, the rapid fluorescent focus inhibition test (RFFIT), is laborious and rather difficult to carry out in horse farms. This study was undertaken to develop a simple latex agglutination test (LAT) for determining rabies antibodies in horse sera. LAT was validated by testing a total of 468 horse serum samples characterized by RFFIT. Of these, 253 of 260 samples with antibody titers of less than 100 IU/ml had agglutination score of 1+, whereas 174 of 208 samples with antibody titers equal to or greater than 100 IU/ml had agglutination scores of 2-4+. Results of LAT correlated with those of RFFIT (r = 0.87, p < 0.0001). LAT has the advantages of being rapid, simple to perform, easy to interpret, and applicable as an on-site testing tool for the estimation of rabies antibodies in horses.

Preparation of acetochlor antibody and its application on immunoaffinity chromatography cleanup for residue determination in peanuts

The preparation of an antibody against acetochlor and its application on immunoaffinity chromatography (IAC) cleanup was investigated. The hapten was synthesized by reacting acetochlor with 3-mercaptopropionic acid and then linked with a carrier protein by the carbodiimide method. After immunizing a rabbit with hapten-bovine serum albumin (BSA) conjugate, the obtained antiserum showed an IC(50) value of 0.2 ng/mL. By coupling the purified polyclonal antibody with CNBr-activated Sepharose 4B, an IAC column was prepared. The dynamic column capacity was 5560 ng/mL gel. The IAC was then used to clean up a peanut sample solution, followed by high-performance liquid chromatography (HPLC) separation and ultraviolet (UV) detection. The recoveries of acetochlor from spiked peanut samples at levels of 5-100 microg/kg ranged from 94.7 to 102.5%, with a variation coefficient of 2.6-8.0%, and the limits of detection and quantification were 1.5 and 5 microg/kg, respectively.

[Expression of human Id-2 gene in Escherichia coli and preparation of the antisera against human Id-2]

OBJECTIVE

To express the fusion protein of glutathione S-transferase (GST) and human Id-2 in E. coli and prepare the polyclonal antibodies against Id-2.

METHODS

The coding sequence of Id-2 gene was amplified by RT-PCR from the total RNA of breast cancer tissue. The recombinant plasmid was identified by PCR, restriction endonuclease digestion analysis and sequencing. The fusion protein GST-Id-2 expressed in E. coli following IPTG induction was purified by glutathione-agarose affinity chromatography and used to immunize rabbits to prepare the polyclonal antibodies against GST-Id-2.

RESULTS

PCR, restriction endonuclease digestion and sequence analyses showed that the Id-2 gene had been correctly inserted into pGEX-6P-1 vector, and the GST-Id-2 fusion protein expressed had a relative molecular mass of approximately 40,000 as shown by SDS-PAGE. The polyclonal antibodies obtained from the rabbit sera were found to specifically react with purified Id-2 by Western blotting, ELISA and agar gel immunodiffusion (AGP).

CONCLUSION

The prepared polyclonal antibodies against Id-2 allow effective Id-2 detection and facilitate further investigation of the structure and antigen epitope of Id-2.

[Expression, antiserum preparation and bioactivity assays of insect neurotoxin LqhIT2]

According to the codon bias of Pichia pastoris, the mature insect neurotoxin gene LqhIT2 was synthesized based on its amino acid sequence and was cloned to vector of PET-30a (+) and pPIC9K respectively. The fusion protein expressed in Escherichia. coli was induced with IPTG and purified with Ni-NTA His Bind Column. The purified fusion protein was used to immunize BALB/c mice, and antiserum obtained was highly specific with the titer of over 1:128 000. Using the antiserum, high-level expression transformants of P. pastoris were screened by dot blotting. The highest expression of recombinant LqhIT2 was about 9 mg/L in baffled flasks. The fusion protein of LqhIT2 expressed in E. coli was not toxic to locust, but the recombinant LqhIT2 expressed in P. pastoris had insecticidal activity against locust through injection.

Enzyme immunoassay for mycophenolic acid in milk and cheese

Mycophenolic acid (MPA) was reacted with N-hydroxysuccinimide and conjugated to keyhole limpet hemocyanin (KLH), and to horseradish peroxidase (HRP), respectively. The MPA-KLH was used to produce anti-MPA antiserum in rabbits. A competitive direct enzyme immunoassay (EIA) for MPA was established with anti-MPA antiserum and MPA-HRP conjugate. The mean 50% inhibition and detection limit of MPA standard curves (n = 103) were 197 +/- 67 and 81 +/- 48 pg/mL, respectively. The EIA was specific for MPA and its synthetic 2-morpholinoethyl ester, mycophenolate mofetil (91% relative cross-reactivity). Raw bulk milk and pasteurized milk, with and without beta-glucuronidase pretreatment, were analyzed by EIA. No MPA was found in milk, at a detection limit of 100 pg/mL (recovery 58-66% at 0.125-2 ng/mL). Blue-veined cheese from the German market (n = 53) was analyzed by EIA, and the detection limit was at 0.5 ng/g (recovery 68-79% at 5-100 ng/g). All but two cheeses contained MPA, although mostly (66%) at levels of <10 ng/g. MPA at 400-1200 ng/g was found in Roquefort cheeses. Highest levels (4-11 microg/g) were found in a German soft cheese preparation. MPA levels in mycelium-rich parts of cheese were 3 times higher than in mycelium-free parts.

Production of polyclonal antisera

Much of modern biology and biochemistry relies on the availability of highly specific antibodies for use in such ubiquitous techniques as immunohistochemistry, ELISAs, immunoprecipitation, and immunoblotting. Thus, the generation of large quantities of specific antibodies directed to proteins or peptides of interest is essential to the success of both basic and applied research programs. In addition, with the advent of antibody-based proteomic strategies for profiling protein expression and post-translational modification, a requirement for timely production of specific antibodies has emerged. Polyclonal antibodies derived from animals immunized with purified proteins or peptides are particularly valuable for use in the laboratory. This unit provides protocols for the production of polyclonal antisera specific for protein antigens in rabbits, rats, mice, and hamsters.

[Optimizing expression and purification of recombinant Salvia miltiorrhiza copalyl diphosphate synthase protein in E. coli and preparation of rabbit antiserum against SmCPS]

The expression plasmid pET32CPS harboring SmCPS gene was transformed into E. coli BL21 trxB (DE3) resulting in recombinant strain E. coli [pET32CPS]. The induction of E. coli [pET32CPS] in different temperatures, induction time, IPTG concentrations and A600 values of E. coli were performed. The optimal expression conditions of SmCPS were characterized according to the orthogonal analysis, and the ratio of the interest protein to total proteins reached to 35.6%. The recombinant SmCPS protein purified by Ni2+ affinity chromatography column was identified by SDS-PAGE and Western blotting, and then used for rabbit immunization. The titer of the rabbit antiserum against SmCPS was about 1:24 300 after the third immunization, and could specifically recognize the antigen of SmCPS protein by Western blotting analysis. The successful preparation of polyclonal antibody against SmCPS laid a foundation for further correlative study between expression of SmCPS and the production of tanshinones in protein level.

[Preparation and application of anti-serum against mouse Foxp3]

AIM

To prepare the high titer and specific anti-serum against mouse Foxp3 and then use them to identify Foxp3 expression in normal mouse tissues.

METHODS

The Foxp3 fragment was amplified by polymerase chain reactions(PCR) and cloned into the prokaryotic expression vector pGEX-6p-2. The recombinant plasmid pGEX-6p-2/Foxp3 was transformed into E.coli BL21(DE3) to be expressed. The expressed fusion protein GST-Foxp3 was analyzed by SDS-PAGE and Western blot. The polyclonal clanti-serum was obtained by immunizing New Zealand rabbits with the purified fusion protein as antigen. The Foxp3 expression in normal mouse tissues was detected by Western blot with the anti-serum.

RESULTS

The expressed products were analyzed by SDS-PAGE and Western blot. The results showed that the molecular weight of the expressed protein was about 45 000. The titer of the anti-serum was above 1:12 800. We observed that the anti-serum could recognize Foxp3 protein expressed in NIH3T3 cells by immunoblotting. Western blot results showed that the Foxp3 protein was expressed highly in spleen, thymus and lymph nodes, less expressed in stomach, but not expressed in skeletal muscle and adipose tissue.

CONCLUSION

High titer antiserum against mouse Foxp3 is produced and can be used to identify the Foxp3 expression in normal mouse tissues.

Measured Neutralizing Titers of IFN-β Neutralizing Antibodies (NAbs) Can Depend on the Preparations of IFN-β Used in the Assay

An immune response to recombinant human protein therapeutics, including type I interferons (IFNs), has the potential to have a serious negative impact on safety and efficacy. Monitoring of patients for neutralizing antibodies (NAbs) often is advisable. In the case of IFN-beta therapy for multiple sclerosis (MS), we obtained reproducible quantitative titers of NAbs using an improved and well-characterized assay based on a 10-fold reduction of a challenge dose of IFN-beta. However, the observed titer was significantly affected by the preparation of IFN-beta used as the assay challenge. NAb titers obtained using IFN-beta1b averaged 3-5-fold lower than titers of the same sample assayed using either IFN-beta1a or human fibroblast-derived IFN-beta. This was the case whether neutralizing serum was obtained from patients on therapy with IFN-beta1a or IFN-beta1b. The reason for this apparent titer difference is not fully understood but appears to be related to protein folding or other structural properties that differentiate the IFN-beta1b both from commercial IFN-beta1a preparations and from human fibroblast-derived IFN-beta.

Genetic Engineering of the Major Timothy Grass Pollen Allergen, Phl p 6, to Reduce Allergenic Activity and Preserve Immunogenicity

On the basis of IgE epitope mapping data, we have produced three allergen fragments comprising aa 1-33, 1-57, and 31-110 of the major timothy grass pollen allergen Phl p 6 aa 1-110 by expression in Escherichia coli and chemical synthesis. Circular dichroism analysis showed that the purified fragments lack the typical alpha-helical fold of the complete allergen. Superposition of the sequences of the fragments onto the three-dimensional allergen structure indicated that the removal of only one of the four helices had led to the destabilization of the alpha helical structure of Phl p 6. The lack of structural fold was accompanied by a strong reduction of IgE reactivity and allergenic activity of the three fragments as determined by basophil histamine release in allergic patients. Each of the three Phl p 6 fragments adsorbed to CFA induced Phl p 6-specific IgG Abs in rabbits. However, immunization of mice with fragments adsorbed to an adjuvant allowed for human use (AluGel-S) showed that only the Phl p 6 aa 31-110 induced Phl p 6-specific IgG Abs. Anti-Phl p 6 IgG Abs induced by vaccination with Phl p 6 aa 31-110 inhibited patients' IgE reactivity to the wild-type allergen as well as Phl p 6-induced basophil degranulation. Our results are of importance for the design of hypoallergenic allergy vaccines. They show that it has to be demonstrated that the hypoallergenic derivative induces a robust IgG response in a formulation that can be used in allergic patients.

Development of an enzyme-linked immunosorbent assay for the detection of pentachloronitrobenzene residues in environmental samples

A competitive enzyme-linked immunosorbent assay (ELISA) for pentachloronitrobenzene (PCNB), a fungicide and chemical intermediate, was developed using a polyclonal antiserum produced against a hapten-protein conjugate of pentachlorophenoxypropionic acid-bovine serum albumin (BSA). An indirect competitive ELISA of PCNB showed an IC50 of 37 ng/mL and a limit of detection (LOD) of 7 ng/mL. The ELISA can tolerate up to 10% (v/v) methanol, 5% (v/v) acetonitrile, or 5% (v/v) acetone without significant fluctuation of Amax and IC50. The assay sensitivity showed little change in a range of pH from 6 to 8 and concentrations of 0.05-0.2 M NaCl in the assay buffer. Very low cross-reactivities were observed for some structurally related compounds except for hexachlorobenzene (12%). The average recoveries of PCNB from fortified well water, river water, and soil samples were in ranges of 88-94, 80-91, and 70-81%, respectively. The correlations between the gas chromatographic and ELISA results were excellent (r 2 >or= 0.97, slopes from 0.86 to 1.10) for those fortified samples. The ELISA is a good alternative tool for monitoring PCNB residues in environmental samples.

Role of eIF3a (eIF3 p170) in intestinal cell differentiation and its association with early development

Eukaryotic initiation factor 3a (eIF3a) has been suggested to play a regulatory role in mRNA translation. Decreased eIF3a expression has been observed in differentiated cells while higher levels have been observed in cancer cells. However, whether eIF3a plays any role in differentiation and development is currently unknown. Here, we investigated eIF3a expression during mouse development and its role in differentiation of colon epithelial cells. We found that eIF3a expression was higher in fetal tissues compared with postnatal ones. Its expression in intestine, stomach, and lung abruptly stopped on the 18th day in gestation but persisted in liver, kidney, and heart throughout the postnatal stage at decreased levels. Similarly, eIF3a expression in colon cancer cell lines, HT-29 and Caco-2, drastically decreased prior to differentiation. Enforced eIF3a expression inhibited while knocking it down using small interference RNA promoted Caco-2 differentiation. Thus, eIF3a may play some roles in development and differentiation and that the decreased eIF3a expression may be a pre-requisite of intestinal epithelial cell differentiation.

[Synthesis of dominant epitopes on N-terminal part of BPI and preparation of corresponding antisera]

AIM

To synthesize B cell dominant epitopes on N-terminal part of bactericidal/permeability increasing protein (BPI) and prepare the corresponding antisera.

METHODS

The antigenicity, hydrophilicity, flexibility, surface probability and secondary structure of N-terminal amino acids 1-199 on BPI were predicted by bioinformatics applications. Two antigen peptides TA/IK were designed and synthesized on the basis of the above analysis. Then the TA/IK were respectively conjugated to keyhole limpet hemocyanin (KLH) and injected into rabbits to prepare corresponding antisera. Indirect ELISA was performed to analyze the antigenicity of TA/IK and to test the titer of the antisera. And Western blot was used to identify the specificity of the antisera.

RESULTS

(1) Two B cell epitope-based peptides TA/IK were successfully synthesized; (2) the peptides could bind to commercial polyclonal antibody, anti-BPI(55); (3) titers of the antisera against TA/IK were up to 1:51,200, 1:25,600, respectively; (4) Western blot analysis revealed that these antisera could specifically react with the standard sample of BPI(55).

CONCLUSION

The two synthetic antigen peptides TA/IK are indeed dominant epitopes of BPI N-terminal part, and the corresponding antisera are competent for detecting and identifying the N-terminal fragments of BPI.

Production of effective luteinizing hormone antisera by two immunization methods

This paper addresses the production of effective luteinizing hormone antisera by two different immunization methods; the traditional and modified methods. The main difference between these two methods is in the immunization procedure. In the modified method, an additional injection of emulsion with complete Freund's adjuvant and only one booster are applied at the third and 28th day from the first injection, respectively. The results of the study indicated the possibility of producing the antiseria using the modified method in short time and better quality than those produced by the traditional methods. The details of both methods are presented together with the results obtained from the antibodies detection. Comparison between these two methods is also presented along with discussions.

MUC1 expression and anti-MUC1 serum immune response in head and neck squamous cell carcinoma (HNSCC): a multivariate analysis

Background

HNSCC progression to adjacent tissue and nodes may be mediated by altered glycoproteins and glycolipids such as MUC1 mucin. This report constitutes a detailed statistical study about MUC1 expression and anti-MUC1 immune responses in relation to different clinical and pathological parameters which may be useful to develop new anti HNSCC therapeutic strategies.

Patients and methods

Fifty three pre treatment HNSCC patients were included: 26 (49.1%) bearing oral cavity tumors, 17 (32.1%) localized in the larynx and 10 (18.8%) in the pharynx. Three patients (5.7%) were at stage I, 5 (9.4%) stage II, 15 (28.3%) stage III and 30 (56.6%) at stage IV. MUC1 tumor expression was studied by immunohistochemistry employing two anti-MUC1 antibodies: CT33, anti cytoplasmic tail MUC1 polyclonal antibody (Ab) and C595 anti-peptidic core MUC1 monoclonal antibody. Serum levels of MUC1 and free anti-MUC1 antibodies were detected by ELISA and circulating immune complexes (CIC) by precipitation in polyethylene glycol (PEG) 3.5%; MUC1 isolation from circulating immune complexes was performed by protein A-sepharose CL-4B affinity chromatography followed by SDS-PAGE and Western blot. Statistical analysis consisted in Multivariate Principal Component Analysis (PCA); ANOVA test (Tukey's test) was employed to find differences among groups; nonparametrical correlations (Kendall's Tau) were applied when necessary. Statistical significance was set to p < 0.05 in all cases.

Results

MUC1 cytoplasmic tail was detected in 40/50 (80%) and MUC1 protein core in 9/50 (18%) samples while serum MUC1 levels were elevated in 8/53 (15%) patients. A significant statistical correlation was found between MUC1 serum levels and anti-MUC1 IgG free antibodies, while a negative correlation between MUC1 serum levels and anti-MUC1 IgM free antibodies was found. Circulating immune complexes were elevated in 16/53 (30%) samples and were also statistically associated with advanced tumor stage. MUC1 was identified as an antigenic component of IgG circulating immune complexes. Moreover, poorly differentiated tumors were inversely correlated with tumor and serum MUC1 detection and positively correlated with node involvement and tumor mass.

Conclusion

Possibly, tumor cells produce MUC1 mucin which is liberated to the circulation and captured by IgG antibodies forming MUC1-IgG-CIC. Another interesting conclusion is that poorly differentiated tumors are inversely correlated with tumor and serum MUC1 detection.

Rapid development of polyclonal antisera against infectious salmon anaemia virus and its optimization and application as a diagnostic tool

Infectious salmon anaemia is an important disease of Atlantic salmon. One of the current methods of diagnosis is the indirect fluorescent antibody test (IFAT), using a monoclonal antibody specific to the haemagglutinin of the virus. The conformationally dependent nature of this antibody could be a drawback in its usefulness in other tests. This study describes the development and optimization of a polyclonal antiserum against infectious salmon anaemia virus, including a method of separating virus from cell culture components within culture supernatant. The antiserum was subsequently optimized for use in a variety of immunological diagnostic tests, including IFAT and an alkaline phosphatase-based immunoassay, and Western blot.

Immunohistochemistry of great scallop Pecten maximus larvae experimentally challenged with pathogenic bacteria

Three challenge experiments were carried out on larvae of the great scallop Pecten maximus. Larvae were bath-challenged with Vibrio pectenicida and 5 strains resembling Vibrio splendidus and one Pseudoalteromonas sp. Unchallenged larvae were used as negative controls. The challenge protocol was based on the use of a multidish system, where the scallop larvae (10, 13 and 15 d post-hatching in the 3 experiments, respectively) were distributed to 2 ml wells with stagnant seawater and exposed to the bacterial cultures by bath challenge. Presence of the challenge bacteria in the wells was verified by polymerase chain reaction (PCR). A significantly increased mortality was found between 24 and 48 h in most groups challenged with V. pectenicida or V. splendidus-like strains. The exception was found in larval groups challenged with a Pseudoalteromonas sp. LT 13, in which the mortality rate fell in 2 of the 3 challenge experiments. Larvae from the challenge experiments were studied by immunohistochemistry protocol. Examinations of larval groups challenged with V. pectenicida revealed no bacterial cells, despite a high degree of positive immunostaining. In contrast, intact bacterial cells were found in larvae challenged with V. splendidus. In the case of larvae challenged with the Pseudoalteromonas sp., positive immuno-staining was limited to visible bacteria inside the digestive area and cells of the mucosa. The experiments confirm that V. splendidus and V. pectenicida are pathogenic to scallop larvae, and that the Pseudoalteromonas strain is probably not a primary pathogen, although it cannot be ruled out as a secondary pathogen.

Immunogenicity of synthetic peptides derived from Plasmodium falciparum proteins

To obtain antibodies suitable to be used in an antigen-capture assay, we have identified, synthesized, and evaluated a series of peptides from different Plasmodium falciparum excretory-secretory proteins: glutamate-rich protein (GLURP); histidine-rich protein 2; histidine-rich protein 3; Falciparum interspersed repeat antigen and, serine-rich antigen homologous. Conformational as well as antigenic predictions were performed using the ANTHEPROT package. Chemical synthesis was carried out by the multiple manual synthesis using the t-boc strategy. The peptides were used as antigens for the preparation of polyclonal antibodies in rabbits. Out of the 14 peptide constructs, eight by ELISA and, six by MABA elicited antibodies that showed correspondence between the predictive study and the immunogenicity obtained in rabbits. All antipeptide (GLURP, HRP2, and FIRA) antisera were found to bind to the corresponding synthetic sequence in an ELISA assay. The binding activity and specificity of antibodies were determined by Western blot with supernatant culture from P. falciparum. Anti-GLURP (IMT-94 and IMT-200) antisera bound to five molecules present in supernatant with molecular weight of 73, 82, 116, 124, and 128 kDa. Anti-HRP2 (IMT-192) antisera recognized a band of 58 kDa. In both cases, the specific molecules were inhibited by preincubation with the homologous peptide. Anti-HRP3, anti-FIRA neither anti-SERPH antisera showed reactivity. Anti-peptides HRP2 antibodies recognized the recombinant protein present in Parasight-F test. The same way, synthetic peptides from HRPII molecule were recognized by monoclonal antibody present in the Parasight-F assay. Our results confirm the potential value of synthetic peptides when inducing monospecific polyclonal antibodies for the development of diagnostic tests based on the capture of antigens.

Vitellogenin induction in the endangered goodeid fish Girardinichthys viviparus: vitellogenin characterization and estrogenic effects of polychlorinated biphenyls

Vitellogenin (VTG) is a widely used biomarker in studies of endocrine disruption induced by xenobiotics such as polychlorinated biphenyls (PCBs). This study evaluates the estrogenic effects of these compounds on the black-fin goodeid Girardinichthys viviparus, an endangered fish species in Mexico with a reduced range of distribution due to pollution of its natural environment. Adult fish born in the laboratory were exposed to half the LC(0) of Inerteen commercial PCB mixture. VTG was determined through an inhibition enzyme-linked immunosorbent assay (ELISA) using a homologous-heterologous system. Male and female fish were killed after 1, 2, 4, 8 and 16 days of exposure. The distal third of each specimen was used for analysis. VTG was obtained from cultured hepatocytes and blood serum of males previously exposed to 17beta-estradiol. VTG molecular mass was 348 kDa. PCBs were found to elicit greater estrogenic effects on VTG induction in males than in females (p<0.05) and sex differences were noted. Time-dependent VTG induction kinetics in males and a stationary phase in females were also observed.

Haemonchus contortus: prokaryotic expression and enzyme activity of recombinant HcSTK, a serine/threonine protein kinase

Members of the PAR-1/MARK serine/threonine protein kinase (STK) subfamily are important regulators of the cytoskeleton, and their characterization can provide insights into a number of critical processes relating to the development and survival of an organism. We previously investigated the mRNA expression for and organization of a gene (hcstk) representing HcSTK, an STK from the parasitic nematode Haemonchus contortus. In the present study, a recombinant form of HcSTK was expressed and characterized. Affinity-purified anti-HcSTK antibodies reacted with native HcSTK in protein homogenates extracted from third-stage larvae (L3) of H. contortus and were also used to immunolocalize the protein around the nuclei of ovarian and intestinal tissues of adult H. contortus. The enzyme activity of the recombinant HcSTK protein was also demonstrated. The findings show that recombinant HcSTK is a functional protein kinase, with activity directed to KXGS motifs, consistent with other members of the PAR-1/MARK STK subfamily.

In vitro expression and antibody preparation of black carp (Mylopharyngodon piceus) GH

The cDNA fragment encoding the mature polypeptide of growth hormone (GH) for the black carp (Mylopharyngodon piceus) was PCR amplified and subcloned into pET-28a. The recombinant expression plasmid pET-bcGH was transformed into E.coli BL21(DE3) and fusion polypeptide containing a 6xHis-tag at the N-terminus was expressed after IPTG induction. The fusion protein band of 23 kDa or so showed immunoreactivity to the polyclonal antibody aganist grass carp GH. The recombinant GH for black carp was purified by affinity chromatography and dialysis. Using the fusion protein as an antigen, through the modified immunization method, the polyclonal antiserum to black carp GH was obtained. Immunochemistry results showed that the antiserum could detect the antigen as low as 4 ng. The protein of 21 kDa in black carp pituitary protein extracts and blood serum could be detected by western blot analysis in which polyclonal antiserum to black carp GH was used as the primary antibody. All these results showed that the polyclonal antiserum against black carp GH was not only effective but also highly specific.

Yersinia pestis outer membrane type III secretion protein YscC: expression, purification, characterization, and induction of specific antiserum

The type III secretion system (YscC) protein of Yersinia pestis plays an essential role in the translocation of Yersinia outer proteins (Yops) into eukaryotic target cells through a type III secretion mechanism. To assess the immunogenicity and potential protective efficacy of YscC against lethal plague challenge, we cloned, overexpressed, and purified YscC using two different bacterial expression and purification systems. The resulting expression plasmids for YscC, pETBlue-2-YscC and pTYB11-YscC, were regulated by robust T7 promoters that were induced with isopropyl-beta-D-thiogalactopyranoside. The intein-fusion pTYB11-YscC system and the six-histidine-tagging pETBlue-2-YscC system were both successful for producing and purifying YscC. The intein-mediated purification system produced about 1mg of soluble YscC per liter of bacterial culture while the YscC-His(6)-tag method resulted in 16mg of insoluble YscC per liter of bacterial culture. Protein identity for purified YscC-His(6) was confirmed by ion trap mass spectrometry. Antisera were produced against both YscC and YscC-His(6). The specific immune response generated in YscC-vaccinated mice was relative to the particular purified protein, YscC or YscC-His(6), which was used for vaccination as determined by Western blot analysis and ELISA. Regardless of the purification method, either form of the YscC protein failed to elicit a protective immune response against lethal plague challenge with either F1 capsule forming Y. pestis CO92 or the isogenic F1(-)Y. pestis C12.

Plasmodium falciparum: Characterization of a late asexual stage Golgi protein containing both ankyrin and DHHC domains

Proteins containing the DHHC motif have been shown to function as palmitoyl transferases. The palmitoylation of proteins has been shown to play an important role in the trafficking of proteins to the proper subcellular location. Herein, we describe a protein containing both ankyrin domains and a DHHC domain that is present in the Golgi of late schizonts of P. falciparum. The timing of expression as well as the location of this protein suggests that it may play an important role in the sorting of proteins to the apical organelles during the development of the asexual stage of the parasite.

Generation of a polyclonal rabbit anti-mouse tissue factor antibody by nucleic acid immunisation

Tissue factor (TF) the cellular receptor and cofactor for factor VII, initiates coagulation and has also been implicated in several coagulation-independent functions, including inflammation, angiogenesis and tumour metastasis. Investigations of TF expression in mouse models of these processes has been limited by the availability of antibodies that specifically recognise mouse TF. We have generated a rabbit polyclonal antibody to mTF by DNA immunisation. This has yielded an antiserum that recognises native mTF in immunohistochemical and flow cytometric analyses. Furthermore, the antiserum is inhibitory in coagulation assays. This antiserum will be a valuable investigative tool in the analysis of mTF expression.

Characterization of the protein components of Nephila clavipes dragline silk

Spider silk is predominantly composed of structural proteins called spider fibroins or spidroins. The major ampullate silk that forms the dragline and the cobweb's frame threads of Nephila clavipes is believed to be a composite of two spidroins, designated as Masp 1 and 2. Specific antibodies indeed revealed the presence of Masp 1 and 2 specific epitopes in the spinning dope and solubilized threads. In contrast, sequencing of specific peptides obtained from solubilized threads or gland urea extracts were exclusively homologous to segments of Masp 1, suggesting that this protein is more abundantly expressed in silk than Masp 2. The strength of immunoreactivities corroborated this finding. Polypeptides reactive against both Masp 1 and 2 specific antibodies were found to be expressed in the epithelia of the tail and different gland zones and accumulated in the gland secreted material. Both extracts of gland secretion and solubilized threads showed a ladder of polypeptides in the size range of 260-320 kDa in gel electrophoresis under reducing conditions, whereas gel filtration chromatography yielded molecular masses of the proteins of approximately 300-350 kDa. In the absence of a reducing agent, dimeric forms of the spidroins were observed with estimated molecular masses of 420-480 kDa according to gel electrophoresis and 550-650 kDa as determined by gel filtration chromatography. Depending on the preparation, some silk material readily underwent degradation, and polypeptides down to 20 kDa in size and less were detectable.

Evolution of B-cell clonal expansions with age

B-cell clonal expansions (BCE) in young mice are transient, detectable for less than 4 weeks. In contrast, BCE in old mice persist more than 2 months. The greater persistence of BCE in old mice does not appear to be due to the age of the host as the survival of phenyloxazolone chicken serum albumin-induced BCE in most old mice was shorter than in young mice. This raises the possibility that persistent BCE seen in old mice develop over time from transient BCE present earlier in life. To test this hypothesis, young C57BL/6 mice were immunized with hen egg lysozyme (HEL) during the first year of life. By 28 months of age, the majority of these mice had developed a benign, persistent BCE associated with a HEL-specific serum mIg. We also investigated whether benign, persistent BCE, present in 18-month-old mice, can evolve into B-cell lymphomas. We observed that four of eight C57BL/6 mice that survived to 29 months of age had developed diffuse large cell lymphomas. In three of these mice, this diagnosis was made by microscopic analysis of the lymphoid organs. In one mouse, a macroscopic lymphoma was present that permitted us to demonstrate that the IgH mRNA CDR3 length and sequence in the malignant lymphoma was derived from a persistent BCE present 11 months earlier. Together these observations are consistent with the hypothesis that stepwise accumulation of genetic alterations combined with Darwinian selection underlies the evolution of B cells from transient BCE in young mice into persistent BCE, serum mIg, and B-cell lymphomas observed in older mice.

Establishment of a specific radioimmunoassay for bovine interferon τ

A radioimmunoassay (RIA) was developed for quantification of bovine interferon (bIFN) tau, conceptus secretory protein, which allows for the maintenance of the corpus luteum during early pregnancy. A cDNA coding bIFN tau was derived from cultured trophoblast cells (TBs). Recombinant (r) bIFN tau was produced in a baculovirus expression system with two different viruses. The RIA was a double-antibody competitive binding assay that used anti-bIFN tau antiserum (raised in rabbits) as the primary antibody, a radioiodinated derivative of bIFNtau as the radioactive tracer, and goat anti-rabbit IgG as the secondary antibody. The antibody did not cross-react with rbIFN alpha, recombinant human IFN beta or recombinant ovine IFN tau. The correct recovery of amounts of rbIFN tau indicated good accuracy. Serially concentrated TB conditioned media, paralleled the standard curve for bIFN tau. The intra-assay and inter-assay coefficients of variation at bIFN tau levels of 7.8 and 15.6 ng/mL were 7.1 and 8.1%, and 11.0 and 8.5%, respectively. bIFN tau was directly detected in uterine flushings obtained from cows at Day 16 of pregnancy. In summary, this assay was suitable for the measurement of bIFN tau.

Targeting fibroblast growth factor-inducible-14 signaling protects from chronic relapsing experimental autoimmune encephalomyelitis

The TNF-related weak inducer of apoptosis (TWEAK) is a TNF family member mediating proinflammatory effects by its receptor fibroblast growth factor-inducible-14 (Fn14). We studied the role of TWEAK/Fn14 in experimental autoimmune encephalomyelitis (EAE) by protein vaccination with TWEAK and Fn14 and recombinant TWEAK-DNA, respectively. TWEAK-DNA vaccination worsened the clinical course of EAE and increased central nervous system (CNS) inflammation. TWEAK increased the secretion of CCL2 [monocyte chemotactic protein-1 (MCP-1)] by CNS endothelial cells and astrocytes in vitro, suggesting CCL2 as a critical mediator of TWEAKs proinflammatory effects. Vaccination with the extracellular domain of TWEAK or with Fn14 resulted in the induction of specific inhibitory antibodies and an amelioration of EAE signs in two different models in rats and mice. Spinal cord inflammatory infiltrates were significantly diminished. Purified IgG from TWEAK- or Fn14-vaccinated rats prevented TWEAK-induced production of CCL2 by endothelial cells. Blocking Fn14 signaling represents a novel approach with potential for the treatment of CNS autoimmunity.

Production of antibodies against degradative neoepitopes in aggrecan

The use of synthetic peptides to generate rabbit polyclonal anticatabolic neoepitope antibodies that can be used to study the presence of defined proteolytic cleavage sites in aggrecan is described. Principles of peptide design and methods for preparation and characterization of ovalbumin conjugates are presented along with approaches for the characterization and affinity purification of the resulting antisera. Limitations associated with the use of antipeptide antibodies to study authentic protein neoepitopes are discussed.

Development of an ELISA for the detection of bromoxynil in water

For development of an indirect competitive enzyme-linked immunosorbent assay (ELISA) for the nitrile herbicide bromoxynil, the polyclonal antibodies raised against 2,6-dibromo-4-cyano-phenoxyacetic acid (hapten) conjugated to bovine serum albumin (BSA) by the N-hydroxysuccinimide-activated ester method. Antiserum with a sufficiently high titer to provide the determinations of targeted compounds was obtained only 77 days after the primary immunization. Antiserum A2 was applied to the residual analysis of some water samples, under optimized ELISA condition, the quantitative working range was from 10 to 500 ppb with a limit of detection of 5 ppb. Cross-reactivity to structurally similar agrochemicals and related chemicals was determined. The antiserum showed little cross-reactivity with 2,6-dibromophenol and bromoxynil octanoate ester which have a dibromophenol group as common structure, but showed no cross-reactivity with other herbicides. Each water sample (river water, tap water, purified water, and bottled water) had a matrix effect and was investigated by adding Tween20 in the assay buffer. These four kinds of water samples were fortified with bromoxynil at several concentration levels and were directly analyzed with only dilution with an equal volume of antiserum solution, the mean recovery was 102.3%, and the mean coefficient of variation was 5.96%. The proposed ELISA turned out to be a powerful tool for monitoring of residual bromoxynil in water samples at trace level.

B cells expressing Bcl-2 and a signaling-impaired BAFF-specific receptor fail to mature and are deficient in the formation of lymphoid follicles and germinal centers

The TNF family cytokine B cell-activating factor belonging to the TNF family (BAFF) (BLyS) plays a fundamental role in regulating peripheral B cell survival and homeostasis. A BAFF-specific receptor (BAFF-R; BR3) appears to mediate these functions via activation of the NF-kappaB2 pathway. Signaling by the BAFF-R is also required to sustain the germinal center (GC) reaction. Engagement of this receptor results in the induction of Bcl-2, suggesting that this antiapoptotic factor acts downstream of the BAFF-R and NF-kappaB2 pathway to promote peripheral B cell survival during primary and Ag-driven development. To test this idea, we created lines of mice coexpressing a Bcl-2 transgene and a signaling-deficient form of the BAFF-R derived from the B lymphopenic A/WySnJ strain. Surprisingly, although dramatically elevated numbers of B cells accumulate in the periphery of these mice, these B cells exhibit extremely perturbed primary development, formation of lymphoid microenvironments, and GC and IgG responses. Moreover, mice expressing the bcl-2 transgene alone display a loss of marginal zone B cells, an expansion of follicular B cells that appear immature, and alterations of the GC reaction. These results suggest that the BAFF-R and Bcl-2 regulate key and nonoverlapping aspects of peripheral B cell survival and development.

Expression, purification, and biochemical characterization of the antiinflammatory tristetraprolin: a zinc-dependent mRNA binding protein affected by posttranslational modifications

Tristetraprolin (TTP) is a hyperphosphorylated protein that destabilizes mRNA by binding to an AU-rich element (ARE). Mice deficient in TTP develop a severe inflammatory syndrome. The biochemical properties of TTP have not been adequately characterized, due to the difficulties in protein purification and lack of a high-titer antiserum. Full-length human TTP was expressed in human HEK293 cells and purified to at least 70% homogeneity. The purified protein was free of endogenous ARE binding activity, and was used for investigating its size, zinc dependency, and binding kinetics for tumor necrosis factor alpha mRNA ARE. A high-titer rabbit antiserum was raised against the MBP-hTTP fusion protein expressed in Escherichia coli. Cellular localization studies of the transfected cells indicated that approximately 80% of the expressed TTP was in the cytosol, with 20% in the nuclei. TTP from both locations bound to the ARE and formed similar complexes. The purified TTP was shown to be intact by N-terminal His-tag purification, C-terminal peptide sequencing, and mass spectrometry analysis. Results from size exclusion chromatography are consistent with the predominant form of active TTP being a tetramer. TTP's ARE binding activity was increased by 10 microM Zn(2+). The half-maximal binding of TTP from HEK293 cells was approximately 30 nM in assays containing 10 nM ARE. This value was about twice that of TTP from E. coli. TTP from HEK293 cells was highly phosphorylated, and its electrophoretic mobility was increased by alkaline phosphatase treatment and somewhat by T271A mutation, but not by PNGase F or S186A mutation. The gel mobility of TTP from E. coli was decreased by in vitro phosphorylation with p42/ERK2 and p38 mitogen-activated protein kinases. These results suggest that TTP's zinc-dependent ARE binding affinity is reduced by half by posttranslational modifications, mainly by phosphorylation but not by glycosylation, in mammalian cells. The results support a model in which each subunit of the TTP tetramer binds to one of the five overlapping UUAUUUAUU sequences of the ARE, resulting in a stable TTP-ARE complex.

Suppression of Ongoing Experimental Autoimmune Encephalomyelitis by Neutralizing the Function of the p28 Subunit of IL-27

IL-27 is a recently defined family member of the long-chain, four-helix bundle cytokines, which consist of EBI3, an IL-12p40-related protein, and p28, an IL-12p35-related polypeptide. The role of IL-27 in the regulation of experimental autoimmune encephalomyelitis has never been studied. We show in this study that neutralizing the in vivo function of IL-27 by Abs against IL-27 p28 rapidly suppressed an ongoing long-lasting disease in C57BL/6 mice. These Abs were then used to determine the mechanistic basis of disease suppression. We show in this study that IL-27 is involved not only in the polarization of naive T cells undergoing Ag-specific T cell activation, but also in promoting the proliferation and IFN-gamma production by polarized T cells, including the long term Th1 line that has been previously selected against the target encephalitogenic determinant. This may explain in part why neutralizing IL-27 suppresses an already established disease in a very rapid and significant manner.

Modulation of the primary and the secondary antibody response by tobacco smoke condensates

Cigarette smoke condensate administered to C57BL/6 mice led to a decrease in the primary antibody response to OVA (hen egg albumin) antigen. Selenium (Se)-supplementation allowed to relieve significantly this inhibition. Moreover, even being not supplemented with Se, a preparation was found devoid of inhibitory effects. Furthermore, the presence of Se-supplemented tobacco smoke condensate at the time of antigen priming, contributed to an enhanced secondary antibody response.

Tyrosine phosphates act on steroidogenesis through the activation of arachidonic acid release

The ACTH signaling pathway includes both PKA activation as well as PKA-dependent tyrosine phosphatase activation. In addition, the action of this hormone also includes the regulation of the intracellular levels of arachidonic acid (AA) by the concerted action of two enzymes: an acylCoA-thioesterase and an acyl-CoA-synthetase (ACS4). This work describes the production and characterization of a specific ACS4 antibody, which was used to analyze the effect of ACTH on ACS4 protein level in Y1 adrenocortical cells and the putative relationship between tyrosine phosphatases and ACS4. The antiserum was obtained from rabbits immunized with the recombinant ACS4. This immunogen was produced in bacteria and eluted from an acrylamide gel after SDS-PAGE separation of a partially purified bacteria lysate. When used in Western blot analysis, the antibody obtained specifically recognized only one protein of the molecular mass corresponding to ACS4, in Y1 cells and in several rat tissues. Using the antibody described here, we analyzed the effect of ACTH stimulation on ACS4 protein level. The hormone produced an increase of this acyl-CoA synthetase in Y1 adrenocortical cells. Moreover, this effect was mimicked by cAMP and partially reduced by a tyrosine phosphatase inhibitor. We propose that ACTH regulates ACS4 protein levels through a PKA-dependent mechanism that could involve also PTP activity.

Generation of competent bone marrow-derived antigen presenting cells from the deer mouse (Peromyscus maniculatus)

Background

Human infections with Sin Nombre virus (SNV) and related New World hantaviruses often lead to hantavirus cardiopulmonary syndrome (HCPS), a sometimes fatal illness. Lungs of patients who die from HCPS exhibit cytokine-producing mononuclear infiltrates and pronounced pulmonary inflammation. Deer mice (Peromyscus maniculatus) are the principal natural hosts of SNV, in which the virus establishes life-long persistence without conspicuous pathology. Little is known about the mechanisms SNV employs to evade the immune response of deer mice, and experimental examination of this question has been difficult because of a lack of methodologies for examining such responses during infection. One such deficiency is our inability to characterize T cell responses because susceptible syngeneic deer mice are not available.

Results

To solve this problem, we have developed an in vitro method of expanding and generating competent antigen presenting cells (APC) from deer mouse bone marrow using commercially-available house mouse (Mus musculus) granulocyte-macrophage colony stimulating factor. These cells are capable of processing and presenting soluble protein to antigen-specific autologous helper T cells in vitro. Inclusion of antigen-specific deer mouse antibody augments T cell stimulation, presumably through Fc receptor-mediated endocytosis.

Conclusions

The use of these APC has allowed us to dramatically expand deer mouse helper T cells in culture and should permit extensive characterization of T cell epitopes. Considering the evolutionary divergence between deer mice and house mice, it is probable that this method will be useful to other investigators using unconventional models of rodent-borne diseases.

Endoxin-mediated myocardial ischemia reperfusion injury in rats in vitro

Myocardial ischemia reperfusion results in an increase in intracellular sodium concentration, which secondarily increases intracellular calcium via Na(+)-Ca2+ exchange, resulting in cellular injury. Endoxin is an endogenous medium of digitalis receptor and can remarkably inhibit Na+/K(+)-ATPase activity. Although the level of plasma endoxin is significantly higher during myocardial ischemia, its practical significance is unclear. This research is to investigate whether endoxin is one of important factors involved in myocardial ischemia reperfusion injury. Ischemia reperfusion injury was induced by 30 min of global ischemia and 30 min of reperfusion in isolated rat hearts. Heart rate (HR), left ventricular developed pressure (LVDP), and its first derivative (+/-dp/dtmax) were recorded. The endoxin contents, intramitochondrial Ca2+ contents, and the Na+/K(+)-ATPase activity in myocardial tissues were measured. Myocardial damages were evaluated by electron microscopy. The endoxin and intramitochondrial Ca2+ contents in myocardial tissues were remarkably higher, myocardial membrane ATPase activity was remarkably lower, the cardiac function was significantly deteriorated, and myocardial morphological damages were severe in myocardial ischemia reperfusion group vs. control. Anti-digoxin antiserum (10, 30 mg/kg) caused a significant improvement in cardiac function (LVDP and +/-dp/dtmax), Na+/K(+)-ATPase activity, and myocardial morphology, and caused a reduction of endoxin and intramitochondrial Ca2+ contents in myocardial tissues. In the present study, the endoxin antagonist, anti-digoxin antiserum, protected the myocardium against the damages induced by ischemia reperfusion in isolated rat hearts. The results suggest that endoxin might be one of main factors mediating myocardial ischemia reperfusion injury.

[Activity assay, antiserum preparation and cellular localization of ustiloxins]

False smut is an increasingly important rice disease in recent years, caused by a pathogen, Ustilaginoidea virens Cooke, Takahashi. The pathogen fungus grew well in PD medium, and could produce toxins, ustiloxins, which strongly inhibited the growth of radicle and embryo of plants. The rough ustiloxins were extracted with 100% methanol from the culture filtrate in the study. The antiserum against Ustiloxin A, the main component of the toxins, was raised by immunizing New Zealand rabbit. Elisa assay showed that the titers of the two antiserums obtained were 1: 20 000 and 1: 6 000, respectively. The specificity of the antiserums was also confirmed by Immuno-gold labeling.

Production of polyclonal antibodies against territrem B and detection of territrem B in the conidia of Aspergillus terreus 23-1 by immunoelectron microscopy

Territrem B, a fungal metabolite isolated from Aspergillums terreus 23-1, is a tremorgenic mycotoxin. Immunoelectron microscopy using anti-territrem B polyclonal antibody was used to detect territrem B in the fungal body of A. terreus 23-1 at different times of culture without shaking on potato dextrose (PD) agar medium. The anti-territrem B serum was produced by immunization of rabbits with 4beta-hydroxymethyl-4beta-demethylterritrem B-sccinate bound by a linker to keyhole limpet hemocyanin. This antiserum recognized territrems and immunoelectron microscopy using this antiserum, and colloidal gold-conjugated anti-rabbit IgG antibodies showed that territrem B was localized to the fungal body of A. terreus 23-1. Territrem B was first seen in the cytoplasm of the conidia after 4 days' culture on PD agar medium. Maximal territrem B production in the conidia was seen on the 14th day of culture; however, territrem B was not formed in the hyphae at any stage of culture. These results are consistent with the previous finding that the formation of territrems is related to fungal sporulation.

The immunogenicity of recombinant and dimeric gonadotrophin-releasing hormone vaccines incorporating a T-helper epitope and GnRH or repeated GnRH units

In this study, we designed two linear peptides, GnRH-hinge-MVP, which consists of human gonadotrophin-releasing hormone (GnRH), hinge fragment 225-232/225'-232' of human IgG1 and a T helper peptide from measles virus protein (MVP), and GnRH3-hinge-MVP, which contains three copies of GnRH (so termed GnRH3). The DNA constructs encoding for the two peptides were fused to the C-terminal encoding sequence of asparaginase, encompassing residues 199-326, through an acid-labile aspartyl-prolyl linker. The chimeric genes were expressed at high levels in Escherichia coli. The fusion proteins were purified to approximate homogeneity by means of washing the inclusion bodies and by ethanol precipitation. The GnRH-hinge-MVP or the GnRH3-hinge-MVP was released from the fusion proteins by cleavage with hydrochloric acid and further oxidized into double-chain miniproteins after purification. Both dimeric constructs proved to be efficient immunogens. It was shown that rats immunized with the immunogens generated antibodies specific for GnRH. The dimeric GnRH3-hinge-MVP containing three copies of GnRH in each chain induced a higher titre of anti-GnRH antibodies than the GnRH-hinge-MVP, containing a single copy of GnRH in each chain. These results demonstrate that combining multicopies or single copies of peptide with hinge fragment of human IgG and T helper peptide from measles virus protein can induce anti-peptide immune responses. Our data also suggest that these methods of preparation and dimerization of the recombinant polypeptides may provide a useful strategy for other polypeptide vaccine developments.

Enzyme-linked immunosorbent assays based on rabbit polyclonal and rat monoclonal antibodies against isoproturon

This work describes the production and characterization of rabbit polyclonal antisera (pAb) and rat monoclonal antibodies (mAb) against isoproturon. Coating antigen and enzyme-tracer formats were developed. Standard curves for isoproturon were conducted either in 40 mM phosphate buffered saline (PBS) or in Milli-Q water. PAb 352 together with the best enzyme tracer revealed in the optimized ELISA (enzyme tracer format) a test midpoint of 1.06 +/- 0.34 microg/L (n = 19, standard set up in Milli-Q water) with a detection limit of about 0.1 microg/L. The comparable ELISA with mAb IOC 7E1 had test midpoints of 0.07 +/- 0.04 microg/L (n = 7, standards in Milli-Q water) and 0.11 +/- 0.08 microg/L (n = 33; standards in 40 mM PBS). The limits of detection were about 0.003 and 0.01 microg/L in Milli-Q water and PBS, respectively. Noticeable cross reactivities (CRs) were seen with the major metabolites, namely 4-isopropylaniline, 4-isopropylphenylurea, and 1-(4-isopropylphenyl)-3-methylurea. With pAb 352, these CRs were 5%, 7%, and 31%, respectively, and with mAb IOC 7E1, they were 3%, 5%, and ca. 19%, respectively. All arylurea herbicides had only minor CRs, which ranged from no CR (e.g., chlorosulfuron) to a maximum of 3.3% (chlortoluron). Influences of organic solvents (methanol, ethanol, acetonitrile, and acetone) were evaluated. Both pAb- and mAb-based immunoassays showed the highest tolerance for methanol, up to 5%. Ethanol and acetonitrile could not be used above 2% without an influence on the assays. The same was true for acetone, although tested only in the mAb-based assay. Water samples of different origins and matrices were spiked and analyzed with these pAb and mAb ELISAs. The results demonstrated that these immunoassays are useful screening tools.