Safety of snake antivenom immunoglobulins: efficacy of viral inactivation in a complete downstream process

Viral safety remains a challenge when processing a plasma-derived product. A variety of pathogens might be present in the starting material, which requires a downstream process capable of broad viral reduction. In this article, we used a wide panel of viruses to assess viral removal/inactivation of our downstream process for Snake Antivenom Immunoglobulin (SAI). First, we screened and excluded equine plasma that cross-reacted with any model virus, a procedure not published before for antivenoms. In addition, we evaluated for the first time the virucidal capacity of phenol applied to SAI products. Among the steps analyzed in the process, phenol addition was the most effective one, followed by heat, caprylic acid, and pepsin. All viruses were fully inactivated only by phenol treatment; heat, the second most effective step, did not inactivate the rotavirus and the adenovirus used. We therefore present a SAI downstream method that is cost-effective and eliminates viruses to the extent required by WHO for a safe product.

Identification of Leishmania infantum chagasi proteins in urine of patients with visceral leishmaniasis: a promising antigen discovery approach of vaccine candidates

Visceral leishmaniasis (VL) is a serious lethal parasitic disease caused by Leishmania donovani in Asia and by Leishmania infantum chagasi in southern Europe and South America. VL is endemic in 47 countries with an annual incidence estimated to be 500,000 cases. This high incidence is due in part to the lack of an efficacious vaccine. Here, we introduce an innovative approach to directly identify parasite vaccine candidate antigens that are abundantly produced in vivo in humans with VL. We combined RP-HPLC and mass spectrometry and categorized three L. infantum chagasi proteins, presumably produced in spleen, liver and bone marrow lesions and excreted in the patients' urine. Specifically, these proteins were the following: Li-isd1 (XP_001467866.1), Li-txn1 (XP_001466642.1) and Li-ntf2 (XP_001463738.1). Initial vaccine validation studies were performed with the rLi-ntf2 protein produced in Escherichia coli mixed with the adjuvant BpMPLA-SE. This formulation stimulated potent Th1 response in BALB/c mice. Compared to control animals, mice immunized with Li-ntf2+ BpMPLA-SE had a marked parasite burden reduction in spleens at 40 days post-challenge with virulent L. infantum chagasi. These results strongly support the proposed antigen discovery strategy of vaccine candidates to VL and opens novel possibilities for vaccine development to other serious infectious diseases.

Trends in adjuvant development for vaccines: DAMPs and PAMPs as potential new adjuvants

Aluminum salts have been widely used in vaccine formulations and, after their introduction more than 80 years ago, only few vaccine formulations using new adjuvants were developed in the last two decades. Recent advances in the understanding of how innate mechanisms influence the adaptive immunity opened up the possibility for the development of new adjuvants in a more rational design. The purpose of this review is to discuss the recent advances in this field regarding the attempts to determine the molecular basis and the general mechanisms underlying the development of new adjuvants, with particular emphasis on the activation of receptors of innate immune recognition. One can anticipate that the use of these novel adjuvants will also provide a window of opportunities for the development of new vaccines.

Robust γδ+ T cell expansion in infants immunized at birth with BCG vaccine

Cell-mediated immune responses to BCG vaccine were evaluated in 7-month-old infants vaccinated with intradermal combined BCG and Hepatitis B or intradermal BCG and intramuscular Hepatitis B at birth. Peripheral blood mononuclear cell cultures from both groups showed CD4(+), CD8(+) and remarkable gammadelta(+) T cell BCG-specific proliferation, without significant differences. Also, IL-10, IL-12, IFN-gamma and TNF-alpha concentrations in culture supernatants, measured by ELISA, were similar. The results suggested that the combined BCG and Hepatitis B vaccine was as immunogenic as BCG separated from Hepatitis B vaccine.

Adjuvant can improve protection induced by OMV vaccine against Neisseria meningitidis serogroups B/C in neonatal mice

Meningococcal outer membrane vesicle (OMV) vaccines are weak antigens in infants. This study aimed at investigating alternative adjuvants for induction of functional antibodies in newborn mice. Serogroup B/C anti-meningococcal vaccines, consisting of capsular polysaccharide from serogroup C (PSC) conjugated to OMV from one serogroup B serosubtype prevalent in Brazil, combined with OMV from another prevalent serosubtype, were tested in newborn and adult mice with the following adjuvants: aluminum hydroxide, MPL (monophosphoryl lipid A), Titermax and MF59. Total IgG, IgG avidity index determination and bactericidal assay were performed with sera from immunized mice. Antibodies induced against PSC in newborn mice showed avidity and bactericidal titers, similar to those obtained in adult mice, independently of the adjuvant. Evidence is presented that the inclusion of MF59 enhanced the immune response against OMV in newborn mice.

Optimization of medium and cultivation conditions for capsular polysaccharide production by Streptococcus pneumoniae serotype 23F

The influence of medium composition and culture conditions on Streptococcus pneumoniae serotype 23F cultivation was investigated in order to develop an industrial method for polysaccharide (PS) production. Acid-hydrolyzed casein (AHC) and dialyzed enzymatically hydrolyzed soybean meal (EHS) were investigated as nitrogen sources, and the vitamin solution of Hoeprich's medium and dialyzed yeast extract as vitamin sources. The influence of initial glucose concentration was also evaluated. In flask experiments, the best nitrogen source for PS production was AHC; EHS yielded small amounts of PS without interfering with bacterial growth. Dialyzed yeast extract provided an approximately 2-fold increase in PS production when compared to Hoeprich's vitamin solution. In a 5-l bioreactor, it was observed that the pneumococcus did not grow under aerobic conditions, CO(2) did not increase PS yield, glucose was inhibitory above 30 g l(-1), and the main glucose catabolism product was lactate, which had an inhibitory effect on cell growth. When anaerobic cultivation was performed under N(2) flow using the optimized medium, 240 mg l(-1) of soluble PS was obtained, which represents a 3-fold increase in yield as compared to that described in the published patent [Yavordios and Cousin (1983) European Patent 0 071515 A1]. Application of these results would considerably simplify upstream and downstream processes for PS production.

An associated process for the purification of immuno globulin G, catalase, superoxide dismutase and albumin from haemolysed human placenta blood

The human placenta is a rich raw material for production of many biopharmaceutical products. Here we describe a co-purification process for the production of four different proteins from haemolysed human placenta blood: IgG, catalase (Cat), superoxide dismutase (Sod) and albumin (Alb). The process can be divided in two parts: the common steps and the specific separation techniques for each protein. The common steps are: extraction, haemoglobin precipitation, concentration/diafiltration and the first Q-Sepharose chromatography step. At this chromatography step the process is branched: while IgG and Cat were recovered in the flow-through, Sod and Alb were eluted separately. IgG and Cat were separated in a second Q-Sepharose chromatography step during which IgG was recovered in the flow-through, whereas Cat bound to the resin. IgG was purified by S-Sepharose chromatography, followed by selective precipitation with n-octanoic acid, yielding about 0.4 g of IgG per kg of placenta. Cat was eluted at the second Q-Sepharose chromatography step and was purified by Blue Sepharose chromatography. A total of 1.8 x 10(6) units of Cat were recovered/kg of placenta, with a specific activity of 45000 units/mg of protein. Sod was further purified by S-Sepharose and Phenyl-Sepharose chromatography steps and recovered in the non-adsorbed fractions. The yield of Sod was 2.1 x 10(5) units/kg of placenta, with a specific activity of 1194 units/mg of protein. Alb purification was followed by a combined process including thermocoagulation and treatment with activated charcoal. The final step was Phenyl-Sepharose chromatography. The process yielded 3.1 g of Alb/kg of placenta. The described methodology was designed to be easily scaled-up for industrial production.

Cross reactivity of different specific Micrurus antivenom sera with homologous and heterologous snake venoms

Coral snakes are the only Elapids in America. They are represented by three genera: Leptomicrurus, Micruroides and Micrurus, of which the latter are the most abundant and diversified group. Little is known about the biochemistry of Micrurus venoms due to low availability. Here, we present a study on the cross reactivity of different specific Micrurus antivenom with homologous and heterologous snake venoms in order to contribute to the generation of more efficient antiserum for therapeutic purposes. The three specific antisera tested, anti-Micrurus corallinus, anti-Micrurus frontalis, and anti-Micrurus spixii, as well as the bivalent anti-elapid venom sera, raised against a mixture (50% each) of Micrurus frontalis and Micrurus corallinus venoms, were assayed by Western Blot against Micrurus and non-Micrurus elapid venoms. An antisera raised against a recombinant alpha-neurotoxin-like protein from Micrurus corallinus venom, only reacted in Western blot with its homologous venom, indicating that this protein is specific for Micrurus corallinus coral snake.

Induction of neutralizing antibodies against diphtheria toxin by priming with recombinant Mycobacterium bovis BCG expressing CRM(197), a mutant diphtheria toxin

BCG, the attenuated strain of Mycobacterium bovis, has been widely used as a vaccine against tuberculosis and is thus an important candidate as a live carrier for multiple antigens. With the aim of developing a recombinant BCG (rBCG) vaccine against diphtheria, pertussis, and tetanus (DPT), we analyzed the potential of CRM(197), a mutated nontoxic derivative of diphtheria toxin, as the recombinant antigen for a BCG-based vaccine against diphtheria. Expression of CRM(197) in rBCG was achieved using Escherichia coli-mycobacterium shuttle vectors under the control of pBlaF*, an upregulated beta-lactamase promoter from Mycobacterium fortuitum. Immunization of mice with rBCG-CRM(197) elicited an anti-diphtheria toxoid antibody response, but the sera of immunized mice were not able to neutralize diphtheria toxin (DTx) activity. On the other hand, a subimmunizing dose of the conventional diphtheria-tetanus vaccine, administered in order to mimic an infection, showed that rBCG-CRM(197) was able to prime the induction of a humoral response within shorter periods. Interestingly, the antibodies produced showed neutralizing activity only when the vaccines had been given as a mixture in combination with rBCG expressing tetanus toxin fragment C (FC), suggesting an adjuvant effect of rBCG-FC on the immune response induced by rBCG-CRM(197). Isotype analysis of the anti-diphtheria toxoid antibodies induced by the combined vaccines, but not rBCG-CRM(197) alone, showed an immunoglobulin G1-dominant profile, as did the conventional vaccine. Our results show that rBCG expressing CRM(197) can elicit a neutralizing humoral response and encourage further studies on the development of a DPT vaccine with rBCG.

Recombinant Mycobacterium bovis BCG expressing pertussis toxin subunit S1 induces protection against an intracerebral challenge with live Bordetella pertussis in mice

The recent development of acellular pertussis vaccines has been a significant improvement in the conventional whole-cell diphtheria-pertussis-tetanus toxoid vaccines, but high production costs will limit its widespread use in developing countries. Since Mycobacterium bovis BCG vaccination against tuberculosis is used in most developing countries, a recombinant BCG-pertussis vaccine could be a more viable alternative. We have constructed recombinant BCG (rBCG) strains expressing the genetically detoxified S1 subunit of pertussis toxin 9K/129G (S1PT) in fusion with either the beta-lactamase signal sequence or the whole beta-lactamase protein, under control of the upregulated M. fortuitum beta-lactamase promoter, pBlaF*. Expression levels were higher in the fusion with the whole beta-lactamase protein, and both were localized to the mycobacterial cell wall. The expression vectors were relatively stable in vivo, since at two months 85% of the BCG recovered from the spleens of vaccinated mice maintained kanamycin resistance. Spleen cells from rBCG-S1PT-vaccinated mice showed elevated gamma interferon (IFN-gamma) and low interleukin-4 (IL-4) production, as well as increased proliferation, upon pertussis toxin (PT) stimulation, characterizing a strong antigen-specific Th1-dominant cellular response. The rBCG-S1PT strains induced a low humoral response against PT after 2 months. Mice immunized with rBCG-S1PT strains displayed high-level protection against an intracerebral challenge with live Bordetella pertussis, which correlated with the induction of a PT-specific cellular immune response, reinforcing the importance of cell-mediated immunity in the protection against B. pertussis infection. Our results suggest that rBCG-expressing pertussis antigens could constitute an effective, low-cost combined vaccine against tuberculosis and pertussis.

The effect of thioacetamide on the activity and expression of cytosolic rat liver glutathione-S-transferase

The effect of thioacetamide (TA), an hepatotoxic and hepatocarcinogenic compound, on the expression and activity of the cytosolic enzyme glutathione-S-transferase (GST) was studied in rat liver. Four h following the administration of 14C-labeled thioacetamide (50 mg/Kg), several subunits of GST were found to be radioactively labeled. A single sublethal dose of TA (250 mg/Kg) decreased by three-fold the expression of class alpha GST at 24-48 h of treatment, but did not significantly affect the transcription of class mu GST. The activity of the enzyme toward 1-chloro-2,4-dinitrobenzene was mildly inhibited (66% of the control) by a 24 h TA treatment and gradually increased thereafter. It is proposed that the covalent binding of TA or its derivative to the GST subunits does not affect the activity of the enzyme. Nevertheless, GST activity inhibition is due to the deleterious effect of TA on GST transcription.

High-level expression of tetanus toxin fragment C-thioredoxin fusion protein in Escherichia coli

An insert of Clostridium tetani DNA corresponding to fragment C of tetanus toxin was amplified by PCR. This 1.4 kb fragment was cloned into the high-expression vector pET32a, under control of the T7 promoter. Expression of this plasmid in Escherichia coli BL21(DE3) resulted in the production of a fusion protein ( approximately 62 kDa) consisting of 112 amino acids of thioredoxin and approximately 450 amino acids of fragment C. This fusion protein was recognized by anti-tetanus toxoid antiserum in an ELISA and on immunoblots. The recombinant fragment-C-thioredoxin protein was purified significantly in one step by Ni(2+)-chelate Sepharose, the final yield being approximately 35 mg/l. Immunization of animals with the recombinant protein produced antibodies that were able to recognize the tetanus toxin. By using this gene-fusion expression system we produced soluble fragment C of tetanus toxin in a high yield, preventing many problems inherent in the use of other expression systems that produce either insoluble fragment C in inclusion bodies, or a soluble form, but in low yield, using E. coli as the expression host.

Albumin purification from human placenta

Albumin is the human protein used mainly for therapeutic purposes. Besides the traditionally used plasma, blood from placenta is an alternative source for albumin purification. We describe here an industrial process for purification of albumin from human placenta. The proposed albumin-purification process, for 50 kg of placentas, comprises: (i) extraction of haemolysed blood with saline and solid/liquid separation by basket centrifugation; (ii) selective precipitation of haemoglobin by ethanol/chloroform and precipitate removal by filtration in a press filter; (iii) concentration/diafiltration of the filtrate in a 30 kDa cross-flow ultrafiltration (CFUF) membrane; (iv) thermo-coagulation at 70 degrees C with sodium octanoate/EDTA; (v) treatment with activated charcoal at pH 3; (vi) concentration/diafiltration of the filtrate in a 30 kDa CFUF membrane; (vii) anion-exchange chromatography Q-Sepharose; (viii) hydrophobic-interaction chromatography with phenyl-Sepharose; and (ix) conditioning and pasteurization. The process yields an average of 4.5 g of albumin/kg of placenta with a purity of 97.1% and A(403) of 0.05 (1% protein). The final product passes pyrogen and toxicity tests in vivo and it does not contain polymers or aggregates, even after the accelerated stability test, as judged by gel filtration, as required by the Brazilian Pharmacopoeia.

Cloning and characterization of an alpha-neurotoxin-type protein specific for the coral snake Micrurus corallinus

During the cloning of abundant cDNAs expressed in the Micrurus corallinus coral snake venom gland, we cloned an alpha-neurotoxin homologue cDNA (nxh1). Two others isoforms were also cloned (nxh3 and nxh7, respectively). The nxh1 cDNA codes for a potential coral snake toxin with a signal peptide of 21 amino acids plus a predicted mature peptide with 57 amino acids. The deduced protein is highly similar to known toxic three-finger alpha-neurotoxins, with four deduced S-S bridges at the same conserved positions. This is the first cDNA coding for a three-finger related protein described so far for coral snakes. However, the predicted protein does not possess some of the important amino acids for the nicotinic acetylcholine receptor interaction. This protein was expressed in Escherichia coli as a His-tagged protein that allowed the rapid purification of the recombinant protein. This protein was used to generate antibodies which recognized the recombinant protein in Western blot and also a single band present in the M. corallinus venom, but not in the venom of 10 other Micrurus species.

Neisseria meningitidis serogroup C polysaccharide and serogroup B outer membrane vesicle conjugate as a bivalent meningococcus vaccine candidate

Neisseria meningitidis serogroup C polysaccharide (PS C) was conjugated to serogroup B outer membrane vesicles (OMV) in order to test the possibility of obtaining a bivalent group B and C meningococcus vaccine. The conjugate and controls were injected intraperitoneally into groups of ten mice with boosters on days 14 and 28 after the primary immunization. The following groups were used as control: (i) PS C; (ii) PS C plus OMV; (iii) OMV; and (iv) saline. The serum collected on days 0, 14, 28 and 42 were tested by enzyme-linked immunosorbent assay (ELISA) for PS C and OMV, and by complement mediated bactericidal assay against serogroups B and C. ELISA for PS C as well as bactericidal titres against serogroup C meningococci of the conjugated vaccine increased eight-fold (ELISA) and 32 fold (bactericidal) after 42 days in comparison with the PS C control group. ELISA for OMV and bactericidal titre against serogroup B meningococci of the conjugate showed no significant difference in comparison with the OMV containing controls. Furthermore, Western Blot assay of the conjugate immune serum did not bind OMV class four protein which is related to the complement dependent antibody suppressor. The results indicate that the PS C-OMV conjugate could be a candidate for a bivalent vaccine toward serogroups B and C meningococci.

Purification of catalase from human placenta

The therapeutic use of an antioxidant complex containing superoxide dismutase and catalase has been proposed for the treatment of several diseases in which reactive oxygen species have an important role. Although superoxide dismutase for human use is commercially available, methods for the production of catalase for human use have not been described. An industrial process was developed for the purification of catalase for human use as a by-product of albumin production from human placenta, comprising two parts: (1) albumin and catalase co-purification steps, including blood extraction from ground placentas, precipitation of haemoglobin with ethanol/chloroform, concentration/diafiltration by tangential filtration and anionic chromatography, by which non-adsorbed catalase was separated from albumin; and (2) catalase purification steps after albumin separation, including a second anionic chromatography step and dye-affinity chromatography. This method provided a final recovery of 27% (70-100% in each step) with 670-fold purification of catalase (85% pure) and a specific activity of 49000 units/mg, which is higher than that of commercially available human catalase. This process permits the co-purification of catalase and albumin and can easily be scaled up.

Conformational stability and antibody response to the 18kDa heat-shock protein formulated into different vehicles

Protein stability is one of the most important obstacles for successful formulation in the development of new-generation vaccines. Here, the 18kDa heat-shock protein (18kDa-hsp) was chemically modified though conjugation with bovine serum albumin or by esterification with N-hydroxysuccinimide ester of palmitic acid. The biologically active conformation of the protein was preserved after chemical modification. The immune responses to the recombinant 18kDa-hsp from Mycobacterium leprae were studied in different presentations: free, copolymerized with bovine serum albumin in aggregates (18kDa-hsp-BSA), and either surface linked to liposomes or entrapped into liposomes. Measuring the antibody production of immunized genetically selected mice has compared the adjuvant effects of liposomes and proteic copolymer. Among the two liposome preparations, the strongest response was obtained with the surface-exposed antigen-liposomes. The copolymer 18kDa-hsp-BSA conferred a high titer of antibody in injected mice, and persisted 70 d after immunization. This approach should prove very useful for designing more effective vaccines by using 18kDa-hsp as carrier protein.

Specific peptides of casein pancreatic digestion enhance the production of tetanus toxin

Casein pancreatic digest is the basic bacterial growth medium used for diphtheria, botulinum and tetanus toxin vaccine production. It is known that the variation in the peptide content of the casein digest directly affects final toxin yields. In this study, the identification and sequences of eight peptides, four to eight amino acids in length, of casein pancreatic digestion, which seem to be involved in the enhancement of tetanus toxin production, are described. They all contain one or two residues of proline/molecule and a predominance of hydrophobic amino acid residues. The most active peptides show a general structure of Pro-aromatic-Pro, and this pattern resembled the motif displayed by bradykinin-potentiating peptides found in snake venoms. By analogy with the mechanism of bradykinin potentiation through inhibition of the proteolytic degradation of bradykinin, it is suggested that the six peptides identified here could protect the tetanus toxin from proteolysis, once secreted by the bacteria.

Cloning of an unusual natriuretic peptide from the South American coral snake Micrurus corallinus

In the course of cloning abundant cDNAs from the South American coral snake Micrurus corallinus venom gland, we characterized a cDNA coding for a putative natriuretic peptide. All the natural natriuretic peptides described so far, possess a ring structure composed of 17 amino acids formed through an S-S bridge which is extended at the N-terminus by few to several amino acids and may be extended at the C-terminus, usually 4-7 amino acids. In contrast, the M. corallinus natriuretic peptide presents several distinct features: (a) the proform of the deduced natriuretic peptide displays an unusual C-terminus extension. This implies that the mature peptide has a long C-terminal tail or it is further extensively processed to result in the mature natriuretic peptide with the expected 4-7 amino-acid extension. (b) the deduced natriuretic peptide presents an unusual internal Cys within the ring structure. This raises the possibility of natriuretic peptides with a smaller ring structure. (c) the putative natriuretic peptide is flanked by two homologous peptides of unknown function. In addition, an analogous peptide was synthesized and assayed on perfused rat kidney, showing a dose-dependent response in urinary volume and sodium excretion. Moreover, northern-blot studies showed that M. corallinus natriuretic peptide transcripts were highly expressed in venom glands, but they were not detectable in other tissues like heart and brain, suggesting a main role for this M. corallinus natriuretic peptide in the venom gland or in the envenomation by this coral snake's bite.

Preliminary report of the use on adults of a recombinant yeast-derived hepatitis B vaccine manufactured by Instituto Butantan

Three 10 micrograms of the recombinant hepatitis B vaccine, manufactured by Instituto Butantan by original technology, were administered in an adult population, mean age 30 years old, following the 0, 1 and 6 months schedule immunization. The clinical trial was considered satisfactory in terms of immunogenicity (anti-HBs titers between 17.5-29500 IU/ l, seroconversion 95.3%) and reactogenicity (no incapacitating side effects).

Purification of fibroblast growth factor-2 from human placenta using tri(n-butyl)phosphate and sodium cholate

Tri(n-butyl)phosphate (TNBP) and sodium cholate (SC) mixtures have been used to inactivate lipid-enveloped viruses like HIV and hepatitis B. We exploited the use of this combination to purify fibroblast growth factor-2 (FGF-2) from human placenta. Human placentas were extracted in the presence of 0.3% TNBP/0.2% SC and the clarified homogenate was adsorbed to S-Sepharose. The active fractions were further loaded onto a heparin-Sepharose column and purified FGF-2 was eluted with 2.0 M NaCl. FGF-2 purified this way was indistinguishable from FGF-2 purified without TNBP/SC in the extraction step in terms of yield, specific activity and biological response. The lipid-enveloped vaccinia virus was used in a parallel experiment to evaluate the inactivation capacity of our protocol. Under the conditions described here, the combined use of TNBP/SC did not eliminate but reduced significantly the number of vaccinia virus PFUs by log 2-3.

Effect of saponin from Quillaja saponaria (molina) on antibody, tumour necrosis factor and interferon-gamma production

Saponin has been described to contain adjuvant activity in vaccination protocols, in protection against disease, and on humoral immune response. In this paper we describe the effect of a pure saponin from Quillaja saponaria (molina) on the immune response elicited in mice by two antigens, BSA and Crotalus durissus terrificus (South American rattlesnake) venom. Antibody production as measured by ELISA shows that saponin was able to increase antibody synthesis to both antigens. Moreover, mice immunized with verom plus saponin were completely protected against the lethal effects of the venom. The effect of saponin was also evaluated for cytokine production. Tumour necrosis factor activity about 2.9 times higher than in control mice was detectable in sera from animals immunized with saponin. Interferon-gamma was produced only when BSA and saponin were injected together into the mice.

Characterization of an endooligopeptidase A-like protein in PC12 cells: activity modulation by cAMP but not by basic fibroblast growth factor

Endooligopeptidase A is a putative neuropeptide-metabolizing enzyme. It converts small enkephalin-containing peptides into the corresponding enkephalins and inactivates biopeptides such as bradykinin and neurotensin in vitro. We investigated the presence of endooligopeptidase A in PC12 cells. This cell line was derived from a rat pheochromocytoma tumor and resembles fetal chromaffin cell. Depending on the supplements added to the cell culture, this cell line can be differentiated into mature chromaffin cell or sympathetic neuron-like cell. Endooligopeptidase A activity was measured in soluble cellular extracts using a specific fluorogenic substrate QF-ERP7. The PC12 endooligopeptidase A-like activity shared similar but not identical biochemical properties with rabbit brain endooligopeptidase A. Similarly to rabbit brain endooligopeptidase A, the PC12 endooligopeptidase A-like activity was enhanced by DTT, totally inhibited by DTNB and 1-10 Phenanthroline, partially inhibited by cFP-AAF-pAb, and not affected by PMSF. Furthermore, the PC12 endooligopeptidase A-like activity displayed identical elution profile as rabbit brain endooligopeptidase A in gel filtration and anion-exchange chromatography. In addition, an antiserum raised against rabbit brain endooligopeptidase A cross-reacted with a 71 kDa component from PC12 cell extracts in Western blotting and was also able to partially neutralize the PC12 endooligopeptidase A-like activity. Treatment of PC12 cells with basic fibroblast growth factor (bFGF), a neurotrophic factor for this cell line, did not modify the specific activity of this enzyme. However, cAMP analogs decreased the specific activity of the enzyme. These results indicate the presence of an endooligopeptidase A-like activity in PC12 cells which is modulated by cAMP but not by bFGF.

Kinetic studies on the membrane form of intestinal alkaline phosphatase

We have purified different membrane and soluble forms of alkaline phosphatase from human placenta and bovine intestine. The enzymes will be used as markers in immunoconjugates and/or as model for membrane enzyme studies. The membrane form of alkaline phosphatase extracted from bovine intestine was purified on Q-Sepharose and on L-histidyldiazobenzyl-phosphonic acid-agarose columns to remove phosphodiesterase activity. The purified enzyme had a molecular mass of 61 kDa, Km of 1208 microM, and Vmax 240 mumol pNP/min when assayed in 1 M diethanolamine, 0.5 mM MgCl2 buffer, pH 9.8, containing 10 to 2250 microM of pNPP at 37 degrees C. In the present investigation we studied the effect of salts and inositol derivatives on this enzyme activity, which was found to depend on 0.5 mM Mg2+, and to be fully inhibited by 1.2 mM Hg2+. Vanadate (0.5 mM) and Zn2+ (0.5 mM) reduced the Km value by 43% and 84%, respectively. Inositol (2 mM) and inositol-2-monophosphate (2 mM) reduced the activity by 23% and 17%. Inositol-1-monophosphate (0.5 mM) and cyclic-inositol-(1:2)-monophosphate (0.5 mM) enhanced their Km value by at least 30% compared to p-nitrophenylphosphate.

Multiparametric analyses of hybridoma growth on glass cylinders in a packed-bed bioreactor system with internal aeration. Serum-supplemented and serum-free media comparison for MAb production

Monoclonal antibodies are one of the most important products of biotechnology and laboratories and companies all over the world are pursuing their large-scale production. Herein we report a protocol for hybridoma cell cultivation over small glass cylinders inside a 3 liter bioreactor vessel which leads to the production and purification--in order of grams--of one MAb intended for human therapeutic use. This protocol proved to be simple, reproducible and cost effective. Three trials are reported: the first two using conventionally serum-supplemented medium culture and producing 3.15 and 2.1 g of purified MAb in 30 and 21 days respectively, and the third one using serum-free medium culture and producing 6 g of purified MAb in 36 days. We have ascertained the stability of the hybridoma by its cloning directly in serum-free medium. The downstream processing of the serum-free trial was done in a single step, concentrating large volumes of supernatant while simultaneously purifying the antibody.

A Bordetella pertussis acellular vaccine candidate: antigenic characterization and antibody induction

A single-step chromatography on Matrex-Gel Blue A has been employed to obtain soluble extracts containing some of the most important antigens of Bordetella pertussis, pertussis toxin (PT), filamentous hemagglutinin (FHA), pertactin (69-kDa outer membrane protein), fimbriae (FIM2 and FIM3) and adenylate cyclase (AC). Two supernatants, P19 (48.8 mg PT, 6.8 mg FHA, 17.3 mg AC, 13 mg FIM2 and 4.9 mg FIM3 per liter) and P21 (0.1 mg PT, 0.07 mg FHA, 0.46 mg FIM2 and 0.94 mg FIM3 per liter), resulting from bacteria grown in Stainer-Scholte medium, were submitted to chromatography. Fractions with the antigens were obtained after stepwise elution with 60 mM sodium phosphate buffer, pH 6.0; 50 mM Tris-HCl, pH 7.4; 50 mM Tris-HCl, pH 7.4/0.75 M MgCl2; 50 mM Tris-HCl, pH 7.4/4 M MgCl2 and 4 M urea. Preparations from P19 (containing 4.05 micrograms PT, 8.14 micrograms FHA, 6.3 micrograms AC, 3.37 micrograms 69-kDa, 9.54 micrograms FIM2 and 2.23 micrograms FIM3) and from P21 (with 0.175 micrograms PT, 0.28 micrograms FHA, 0.002 micrograms 69-kDa, 0.005 micrograms FIM2 and 0.122 micrograms FIM3) were detoxified with glutaraldehyde and tested as an acellular pertussis vaccine. These products were non-toxic for mice and induced high levels of antibodies against purified pertussis antigens, as judged by ELISA.

Characterization of different membrane forms of placental alkaline phosphatases

We have extracted and purified four alkaline phosphatase forms from human term placenta. The enzymes are dependent on Mg2+ for their activity. They can be distinguished by different responses to Zn2+, vanadate and inositol derivatives.

Preparation of human rabies vaccine in VERO cell culture using a microcarrier system

1. The rabies virus (Pasteur PV strain) was propagated in VERO cells attached to microcarriers in a 3.7-1 bioreactor. Virus titers of about 10(6) LD50/ml were obtained regularly. 2. Ultrafiltration was efficient for concentrating the virus suspensions, and the sucrose gradient reduced the residual VERO cell DNA to acceptable levels (less than 50 pg/dose). The remaining cell DNA content was evaluated by dot-blot hybridization with a probe prepared with VERO cell DNA. 3. The final virus preparations were inactivated by B-propiolactone treatment, showed a potency higher than 2.5 IU/dose and protected mice experimentally infected intracerebrally with rabies virus (CVS-13.2). 4. This methodology for the production of a rabies vaccine for human use should be of interest to countries where high technology facilities are not available.

Purification of superoxide dismutase from placental haemolisate blood: a simple and efficient method

Superoxide dismutase functions as a scavenger of superoxide radical protecting living organisms. This enzyme has potential use as anti-inflammatory or anti-reperfusion injury drug. Here we present a simple and efficient SOD purification method from human placental blood. Superoxide dismutase from clarified haemolysed placental blood after chloroform and ethanol treatment was purified by DEAE-Sepharose, Phenyl-Sepharose chromatographies and cross flow ultrafiltration. The purified product is 98% pure by SDS-PAGE with 71% yield and specific activity of 2.8 x 10(5) U/mg protein.

Characterization of the snake venoms from seven Brazilian species of Bothrops by FPLC anion-exchange chromatography

1. The elution profiles and the caseinolytic, myotoxic, coagulant and hemorrhagic activities of the venoms of seven Bothrops species fractionated on a Mono-Q FPLC column were analyzed. 2. Each venom separated into 16-20 peaks, with good reproducibility and the activities were concentrated in virtually discrete regions of the chromatogram. 3. There is a considerable overlap of active proteins in the different species venoms and our results indicate that a venom pool with the species B. jararaca, B. jararacussu, B. moojeni, B. neuwiedi and B. atrox venoms would contain the major active proteins determined in the seven species.

Cyclic AMP potentiates bFGF-induced neurite outgrowth in PC12 cells

We report here that basic fibroblast growth factor (bFGF)-elicited neurite outgrowth in PC12 cells is potentiated by dibutyryl cyclic adenosine monophosphate (dbcAMP) or forskolin. This property was also described for nerve growth factor (NGF), suggesting that both NGF and bFGF may share common intracellular events leading to neurite outgrowth and synergism with dbcAMP and forskolin. The synergistic effect of dbcAMP and forskolin is specific, since treatment of PC12 cells with bFGF and dibutyryl cyclic guanosine monophosphate (dbcGMP) or phorbol ester did not change the neurite outgrowth response of cells treated with bFGF alone. Furthermore, neurite outgrowth depends on cellular adhesion. Increasing adhesion by plate treatment with poly-d-lysine increases the neurite outgrowth elicited by bFGF alone or bFGF plus dbcAMP. On the other hand, decreasing cellular adhesiveness by plating PC12 cells in semi-solid agarose renders the cells unable to develop neuritic processes. In addition, 3H-methylthymidine incorporation studies showed that bFGF-treated PC12 cells cease growth only when they become fully differentiated after 3-5 days of treatment. In contrast, dbcAMP, which is a poor differentiation factor, is able to block cellular growth after 24 hour treatment. These results suggest that when PC12 cells become differentiated, they stop growing. However, growth inhibition does not necessarily lead to differentiation.

Bioactivity of skeletal muscle proteolysis-inducing factors in the plasma proteins from cancer patients with weight loss

We determined the circulating level of bioactivity for skeletal muscle proteolysis-inducing factors (PIF) in the blood samples from cancer patients whose body weight loss was greater than 10%. The level of bioactivity was estimated by measurement of tyrosine release from isolated 1at diaphragm muscles incubated with an ultrafiltered fraction of plasma or serum proteins containing molecules from 0 to 25 kDa in molecular weight. Significant levels of bioactivity were detected in 25 of the 50 cancer samples. No activity was found in 18 of the samples from healthy human blood donors. The ability of 13 of the cancer samples to induce muscle proteolysis was significantly inhibited by incubation of muscles in presence of indomethacin (10 microM). The neutralisation of 12 of the cancer samples with the antibodies to recombinant human interleukin-1 (IL-1), alpha and beta forms, partially abrogated the activity in five samples. These results suggest that the accelerated breakdown of proteins induced by the cancer plasma factors is at least in part mediated by IL-1 in cooperation with other active factors not yet defined. Additionally, we have shown that the increased breakdown of proteins induced by PIF in the crude supernatant derived from activated mouse peritoneal macrophages is prevented by the treatment of muscles with either indomethacin or quin-2 (1 microM). These observations provide indirect evidence for a possible causal relationship between the production of PIF and the body-weight loss of cancer patients.

Effect of extra-hepatic Walker sarcoma 256 on the synthesis and degradation of liver cytochromes P-450 and b5

Extra-hepatic Walker sarcoma 256 produced a marked decrease (approximately 60%) in the levels of cytochrome P-450 and NADP-cytochrome P-450 reductase in rat liver endoplasmic reticulum, and a lesser decrease (approximately 20%) of cytochrome b5 and NADH-cytochrome b5 reductase. Polychlorinated biphenyls induced the synthesis of these cytochromes and reductases to approximately the same extent both in normal and tumor-bearing rats. The double-label technique was used to demonstrate that the synthesis of cytochromes P-450 and b5 was reduced in the liver of tumor-bearing rats. The turnover of P-450 was not affected by the tumor, whereas cytochrome b5 turnover was decreased. It is proposed that Walker sarcoma 256 mainly affects the transcription of cytochromes P-450 and b5 through a toxohormone, and that a regulatory mechanism coordinates the level of each cytochrome and its respective reductase.

The possible role of ATP-dependent proteolysis on the solubilization of methemoglobin reductase during reticulocyte maturation

The ATP-dependent proteolytic system present in reticulocytes can release the active hydrophilic domain of cytochrome b5 and NADH-cytochrome b5 reductase from the endoplasmic reticulum, that in mature erythrocytes act as methemoglobin reductase.

Effect of drugs and hormones on rat liver dimethylaminoazobenzene reductase activity

1. Rat liver endoplasmic reticulum catalyzes the reduction of 4-dimethylaminoazobenzene (DAB) by NADPH to dimethyl-p-phenylenediamine and p-aminophenol. This azoreductase activity was inhibited by cyanide and cytochrome b5 antibody, but was resistant to carbon monoxide and SKF-525A (beta-diethylaminoethyl-diphenylpropylacetate). 2. DAB azoreductase activity was induced by 20-methylcholanthrene and phenobarbital, and increased in streptozotocin-induced diabetes or fasting. It was repressed by treatment with DAB and its 3'-methyl derivative, but not by several other derivatives with substitutions in the dimethylaminoazobenzene ring. 3. Azoreductase activity, NADPH-cytochrome P-450 reductase, cytochromes P-450 and b5 were measured in liver microsomes prepared from fasted animals and from animals treated with 20-methylcholanthrene, phenobarbital, streptozotocin or 3-aminotriazole plus allyl-isopropylacetamide. No direct correlation could be established between the variations of azoreductase activity and those of cytochromes P-450 and b5, and of NADPH-cytochrome P-450 reductase in these experimental situations. Since these known carriers do not seem to be the limiting factors for the azoreductase activity, the participation of an unknown carrier that can be repressed by dimethylaminoazobenzene is postulated. 4. Dimethylaminoazobenzene treatment did not reduce the rate of synthesis of microsomal proteins but rather increased the turnover rate of proteins with molecular weights of about 17, 30 an 35 kdal. Since streptozotocin increased the synthesis of proteins with molecular weights of 17, 32, and 48 kdal it is suggested that one of these proteins may correspond to the postulated carrier that is the limiting factor in DAB reduction.

Effect of a single dose of inducers and inhibitors on the rate of synthesis of cytochromes and reductases in liver organelles

Measurement of the effect of drugs on the in vivo rates of synthesis of rabbit liver organelle bound proteins were measured following individual treatments with the inducers phenobarbital, 3-methylcholanthrene and PCB (a mixture of polychlorinated biphenyls) and the inhibitors, cycloheximide, aflatoxin B1, chloramphenicol and actinomycin D. Following their isolation from a homogenate containing the combined livers of 14C-leucine injected experimental animals and 3H-leucine injected control animals, purified fractions of the following proteins were prepared: microsomal cytochrome b5, cytochrome P-450, NADH-cytochrome b5 reductase, NADPH-cytochrome P-450 reductase and proteolipids, outer mitochondrial membrane cytochrome b5, NADH-cytochrome b5 reductase and proteolipids, inner mitochondrial membrane cytochrome c, NADH dehydrogenase and proteolipids, intermitochondrial membrane cytochrome b5 and circulating serum albumin. The effect of a drug was examined by measuring the 14C/3H ratio of leucine incorporation of each fraction; ratios which differed markedly from a control value of 1 represented actual changes in the relative rates of protein synthesis. Increased rates of synthesis of cytochrome P-450 and its reductase, intermitochondrial membrane cytochrome b5 and all three proteolipid fractions resulted from each inducer treatment. Treatments with 3-methylcholanthrene and PCB also increased the rate of synthesis of cytochrome b5 and its reductase in both the microsome and outer mitochondrial membrane. In addition, the PCB treatment increased the rates of synthesis of cytochrome c and NADH-dehydrogenase. The rates of synthesis of cytochromes, reductases and of circulating serum albumin were inhibited following treatments with cycloheximide, aflatoxin B1 and actinomycin D. Actinomycin D appeared to inhibit the release of newly synthesized albumin into the bloodstream while chloramphenicol treatment appeared to inhibit the incorporation of cytochrome c into the mitochondria. After 20 hours of treatment with inhibitors, the inhibitory effect of actinomycin D and cycloheximide were still apparent while the rates of protein synt;esis in chloramphenicol and aflatoxin B1 treated animals increased to levels above the controls. The incorporation of radioactively labeled leucine into the proteolipids of the microsomal, and the outer and inner mitochondrial membranes were inhibited following the treatment with actinomycin D and stimulated following the treatment with cycloheximide.

Some properties of cytochrome b5 from liver microsomes of man, monkey, pig and chicken

1. Cytochrome b(5) was released from liver microsomes of man, monkey, pig and chicken by incubation with a crude lipase preparation. 2. By using DEAE-cellulose chromatography, ammonium sulphate fractionation, Sephadex-gel filtration and a final gradient elution on DEAE-Sephadex A-50, cytochromes b(5) were obtained from the four species studied, all possessing similar spectral properties. 3. Stokes radii of the cytochromes were measured by gel filtration. 4. N-Terminal amino acids for the different cytochromes were serine for man and monkey, alanine for pig and glycine for chicken. 5. Amino acid analyses of the cytochromes are presented. 6. Peptide ;fingerprint' patterns of tryptic digests of the different cytochromes are discussed and clearly show increasing similarity for more closely related species.

In Vitro Uptake of Labelled Amino Acids by the Skin of Children with Generalized Congenital Analgesia

The “in vitro” uptake of labelled tyrosine, tryptophan and leucine by the skin of two children with GCA (Generalized Congenital Analgesia) was compared with that in normal (white and negro) individuals. Through radioactivity counts and radioautographic procedures it was shown that the uptake of the two aromatic amino acids was reduced in the GCA individuals the protein synthesis seemed to be normal.

The possible relationship of these results to an abnormal metabolite isolated from the urine of these patients is discussed.

The effect of ribonuclease on rat-liver ribosomes

1. Rat-liver ribosomes lose about 50% of their amino acid-incorporating activity when preincubated with ribonuclease. 2. This preincubation results also in loss of about 50% of the original protein content and 75% of the RNA. 3. Ribosomes sedimented by ultracentrifugation, after preincubation with ribonuclease, show negligible contamination by crystalline enzyme. 4. Washing of ribosomes treated with ribonuclease releases further protein, restoring the original RNA/protein ratio. 5. The washed particle is again capable of promoting amino acid incorporation. 6. Examination of ribosomes treated with ribonuclease in the analytical ultracentrifuge reveals destruction of ribosomes, disappearance of dimers and a decrease in the sedimentation coefficient of monomers. 7. Washed ribosomes consist of even smaller particles with a sedimentation coefficient 60s.