Immunochromatographic analysis of bovine growth hormone releasing factor involving reversed-phase high-performance liquid chromatography-immunodetection

We have developed high-performance immunoaffinity chromatography (HPIAC) methods for the detection and quantitation of bovine growth hormone releasing factor (GHRF), which could also be applicable to its metabolites in biofluids. These approaches have involved a combination of IAC using immobilized antibody (Ab) to GHRF, together with reversed-phase high-performance liquid chromatography (RP-HPLC) separations of initially isolated and concentrated protein, followed by selective detection, involving on-line immunodetection (ID) schemes. ID methods involved HPIAC supports of the Ab, together with synthesized Ab-fluorescein isothiocyanate conjugates. We have demonstrated optimization methods for each step of the entire hyphenated technique (IAC-HPLC-ID), and then actually quantitated GHRF using this overall system. The minimum detectable concentration was about 1 ng/5 ml (200 ppt) with fluorescence detection (excitation wavelength, 490 nm; emission wavelength, 510-650 nm). We have also tested a single blind, spiked biological sample (bovine plasma), spiked with a known level of GHRF. Accuracy (7.4%) and precision (S.D. = +/- 22%) were quite acceptable for a double immunoassay method.

[The immunogenicity and heterogeneity of Pseudomonas pseudomallei surface antigen 8]

Surface antigen 8, one of pathogenicity factors of P.pseudomallei and having an antiphagocytic action, contains glycoprotein with a mol. wt. of 200 kD and proteins with mol wt. of 25, 30 and 34 kD. According to its chemical structure, the carbohydrate part of antigen 8 is the homogeneous polymer of 6-d-D-mannoheptose, and its protein component is a collection of monomer proteins with mol. wt. of 12-120 kD. The consecutive fractionation of antigen 8 by gel and ion exchange chromatography has made it possible to isolate its individual fragments, differing by the collection of antigenic components, as well as by their antiphagocytic and protective activity. Experiments have shown that glycoprotein with a mol. wt. of 200 kD is an active immunosuppressive agent, while protein with a mol. wt. of 34 kD produces a pronounced immunogenic effect.

A general bacterial expression system for functional analysis of cDNA-encoded proteins

A general system for functional analysis of cDNA-encoded proteins is described. The basic concept involves the expression in Escherichia coli of selected portions of cDNAs in an approach toward the understanding of the function of the corresponding proteins. A selected cDNA is expressed as part of a fusion protein used for immunization to elicit antibodies, and a corresponding fusion protein, having the cDNA-encoded portion in common, for purification of target protein-specific antibodies. This antiserum could be used for functional analysis of the cDNA-encoded protein, e.g., by immunohistology. Two general expression vector systems for E. coli have been constructed, both (i) designed with multiple cloning sites in three different reading frames, (ii) having their protein production controlled by the tightly regulated T7 promoter, and (iii) enabling affinity purification of the expressed target proteins by fusions to IgG-binding domains derived from staphylococcal protein A or a serum albumin-binding protein derived from streptococcal protein G, respectively. This novel system has been evaluated by expressing five cDNAs, isolated from prepubertal mouse testis by a differential cDNA library screening strategy. All five clones could be expressed intracellularly in E. coli as fusion proteins with high production levels, ranging from 4 to 500 mg/liter, and affinity purification yielded essentially full-length products. Characterization of affinity-purified antibodies revealed that there exists no cross-reactivity between the two fusion systems and that such antibodies indeed could be used for immunohistology. The implications for the described system for large-scale functional analysis of cDNA libraries are discussed.

Preparation of serotype specific antiserum against porcine adenoviruses in mice

Serotyping of porcine adenoviruses needs type-specific antiserum. The injections of purified virions to SPF Balb/C mice, followed by an intraperitoneal injection of Ehrlich ascitic tumour cells, gave enough ascitic fluid containing practically applicable type-specific antibody.

[Toxoplasma gondii: the characterization of an anti-P30 monoclonal antibody]

A specific monoclonal antibody was characterized to Toxoplasma gondii. The hybridoma produced IgG immunoglobulins. The western blot analysis showed that the monoclonal antibody was specific for the antigen of an apparent molecular mass of 30 kd, which was present on the antigen surface. The monoclonal antibody was purified starting from mouse's ascitic fluid and it was matched with sepharose 4B. This immunoabsorbent was used to purify the specific parasitic antigen. The monoclonal antibody studied may be useful for those techniques contributing to the toxoplasmosis diagnosis.

[ELISA in the rapid diagnosis of influenza using as the detecting antibodies polyclonal antinucleoprotein sera]

Hyperimmune polyclonal sera were obtained in order to use them as capture and detecting antibodies in rapid diagnostic of influenza A and B viruses by ELISA. The test shown 100% specificity. The sensitivity in directly detection of influenza viruses in human samples compared of influenza isolations was 49,25% for type A and 53,33% for type B. The sensitivity was increased after 48 hours from inoculation of human samples in cell culture-86,75% for type A detection and 80,0% for type B detection from supernatant mammalian tissue culture (MDCK).

The thyroperoxidase doublet is not produced by alternative splicing

Thyroperoxidase is a membrane-bound, heme-containing enzyme which catalyses iodination of thyroglobulin and coupling of resulting iodotyrosines to produce thyroid hormone. In addition to the full length molecule of 933 amino acids (TPO1), Northern blotting and sequencing have revealed several shorter transcripts. The most abundant is a species lacking 171 nucleotides in which the alternative splicing results in the deletion of codons 533-590 in exon 10 (TPO2). Evidence for TPO2 transcripts being translated into a protein is lacking, but in Western blots TPO invariably appears as a doublet of 110 and 105 kDa. In the present study we have produced two recombinant fusion proteins for: (i) the 57 amino acids which are spliced out in TPO2 and (ii) for the 20 amino acids which bridge the splice site (10 amino acids on both sides). Both recombinant fragments have been produced in the pMAL-cRI vector as a maltose-binding protein (MBP) fusion, permitting their purification from a bacterial lysate on an amylose column. Rabbits have been immunized by intradermal injection of 500 micrograms of fusion protein, initially in complete Freund's adjuvant followed by two boosts, at 2-week intervals, in incomplete Freund's adjuvant. The resulting high titre immune sera (IS) were reactive with the relevant immunising antigens, when tested by ELISA. Depletion of each serum by passage through an MBP-CNBr Sepharose column allowed purification of antibodies against the relevant peptides, as demonstrated by ELISA with the appropriate fusion protein and MBP. This demonstrates that we have produced specific polyclonal antibodies for the 57 amino acids unique to TPO1 and for the amino acid segment bridging the splice site, found in TPO2. These polyclonal antibodies were used in Western blotting experiments with normal and Graves' thyroid membranes, in reducing and non-reducing conditions. Monoclonal 47/C21 which recognises a linear epitope (amino acids residues 710-722) common to TPO1 and TPO2 was used as a control. In non-reducing conditions, we observed a broad signal at 105-110 kDa, which appeared to comprise two bands, with both polyclonal antibodies and the monoclonal. There was no difference in the image between the normal and the Graves' thyroid. In reducing conditions, the broad signal resolved clearly into two distinct bands, one at 105 and the other at 110 kDa. Once again we observed exactly the same pattern of reactivity with all three antibodies both in normal and Graves' glands. We conclude that the TPO doublet is not the consequence of translation of TPO2.

Molecular mimicry: histone H3 and mycobacterial protein epitopes

A 15-kDa protein detected initially in amyloidotic ileum from a transgenic mouse and subsequently in control (nontransgenic) ileum by various polyclonal rabbit antiserums applied to electroblots of extracts derived from these tissues was identified by partial sequence analysis as histone H3. Antiserums were made against immunogens unrelated to the histone, but they recognized calf thymus histone H3 (14.7 kDa) on Western blots. The bacterial component of the Freund's medium used as an adjuvant for the immunogens was either Mycobacterium butyricum or Mycobacterium smegmatis. Absorption tests with histone H3 and sonicated M. butyricum substantiated the presence of anti-histone H3 activity in the antiserums. These findings indicate that the two mycobacterium species make a protein with epitopes perceived as nonself by recipient rabbits but sufficiently similar to epitopes of mammalian histone H3 that the rabbits produced antibodies cross-reactive with the histone.

Studies on the reactivity of acyl glucuronides--VIII. Generation of an antiserum for the detection of diflunisal-modified proteins in diflunisal-dosed rats

Acyl glucuronide metabolites of carboxylic drugs such as the salicylate derivative diflunisal (DF) have been shown to react with proteins to produce covalent adducts. To aid in the study of the formation and distribution of these adducts in both humans and rats, we raised an antiserum against human serum albumin modified by covalent attachment of DF via an amide bond, using a carbodiimide reagent. This antiserum had wide reactivity, reacting with all types of DF-modified proteins tested and with free DF (albeit at a lower affinity). It did not cross-react with other salicylates or other non-steroidal anti-inflammatory drugs. The antiserum has been used in immunoblotting to detect proteins covalently modified by DF in the plasma and livers of rats treated with the drug for 7 days. Although some cross-reactivity was apparent on the blots, a series of DF-modified proteins was found in cytosolic, mitochondrial and mixed membrane fractions of hepatocytes, with molecular weights ranging from 28 to 130 kDa.

[Cuban epidemic neuropathy. II. The antigenic characteristics of the viral isolates]

With the aim of characterizing antigenically isolations producing mild cytopathogenic effect obtained from the cerebrospinal fluid of patients presenting with epidemic neuropathy, neutralization tests and western blot analysis were performed using hyperimmune sera of patients and hyperimmune sera of rabbits. It was confirmed that isolations with mild cutopathogenic effect studied have the same antigenic characteristics and that they are related to Coxsackie A9 and B4 viruses. Structural proteins were not detected in the strains with mild cytopathogenic effects, only antigens having a high molecular weight which were considered as precursor proteins for viral replication were confirmed.

[The results of a 15-year study of the persistence of Yersinia pestis L-forms]

New diagnostic preparations for the detection of L-forms, immunoglobulin erythrocyte diagnosticum and luminescent antimembrane immunoglobulins, are described. Proofs indicating that Y.pestis L-forms are constantly isolated from wild rodents and their ectoparasites in the natural foci of plague are given. To control the effectiveness of the sanitation of such natural foci, the use of the radioimmunoassay and the enzyme immunoassay, known to be the most sensitive techniques, are recommended. The facts indicating that Y.pestis contaminating ticks and fleas are converted into L-forms, capable of persisting for several years, are presented. After their reversion to back the initial rod-shaped form the transmission of infection is possible. A suggestion is put forward that the persisting forms of Y.pestis play an important role in the preservation of this infective agent in the natural focus of infection.

[Sorbed animal immunoglobulins--a reserve for increasing the output of therapeutic antitoxic and diagnostic sera]

Conditions for the desorption of immunoglobulins from the surface of blood cells of animals used for the production of antitoxic therapeutic and diagnostic sera have been established. The possibility of obtaining, in principle, additional amounts of immunoglobulins and specific antibodies (in comparison with their initial content in sera) without increasing the number of producer animals has been demonstrated. The possibility of using desorbed immunoglobulins and specific antibodies in the production of therapeutic and diagnostic immunobiological preparations is discussed.

Rapid purification of antiserum against Mycoplasma hyopneumoniae by an efficient absorption method

A simple and efficient method for the removal of unwanted cross-reactive antibodies has been developed. The antiserum purification method was based on treatment of the antiserum with both sonicated extracts and boiling extracts of the Escherichia coli host cells used in immunoscreening the lambda EMBL3 library. We have demonstrated unambiguously that through this simple treatment, the rabbit anti-Mycoplasma hyopneumoniae antiserum can be effectively purified so that the amount of antibodies cross-reacted with Escherichia coli lysate proteins is drastically reduced. Compared with the traditional absorption methods, which require the chemical coupling of an absorbing agent to an insoluble support, and affinity purification methods, which have harsh denaturing condition, this method should greatly facilitate a successful immunoscreening experiment.

[The isolation of hyperimmune horse serum to the Ebola virus]

Immunization of horses with Ebola virus resulted in the production of specific virus-neutralizing antibody with maximum titres at 28-42 days. Repeated cycles of immunization led to a rise in antibody titres to 1:4096.

Immunochemical and antigenic characterization of Coxiella burnetii strains isolated in Europe and Mongolia

SDS-PAGE, immunoblotting and serological methods such as microimmunofluorescence (MIF) test and ELISA were used to compare protein and lipopolysaccharide (LPS) profiles and antigenicity of 12 Coxiella burnetii strains isolated mostly from ticks in Europe and Mongolia with three reference C. burnetii strains originating from USA, namely Nine Mile from tick, Priscilla from goat placenta and S from human heart valve. Among strains from Europe and Mongolia, no significant differences in protein and LPS profiles were observed, irrespective of their origin, i.e. the country and source of isolation. The LPS profiles of these strains appeared to be more related to those of Nine Mile strain associated with acute Q fever, than to those of strains S and Priscilla associated with chronic Q fever. In immunoblots all strains isolated from Slovakia and Poland reacted more expressively with rabbit serum against Nine Mile than with serum against Priscilla strain. In the MIF test and ELISA there were no substantial differences in antibody-binding capacity between the reference and newly isolated C. burnetii strains, except for strain Priscilla reacting with homologous serum in lower antigenic concentration than other strains under study. However, in the MIF test much higher antigenic concentrations of each C. burnetii strain was required to detect antibodies in the Priscilla serum than in the Nine Mile, Luga and S sera.

[Weak androgens, their importance experimentally and clinically]

Antisera obtained for certain hormones possessed a high specific effect on homologous hormones. Radioimmunological methods were worked out for determination of these hormones in the blood serum of humans and animals. Clinical use of the above antisera for determination of dehydroepiandrosterone and androstenedione in humans revealed than it could be useful to determine dehydroepiandrosterone in some forms of hypogonadism. Androstenedione is often increased in female hirsutism.

Relevance of oestrone presentation to the specificity of the elicited antisera, as revealed by affinity separation

Polyclonal antisera raised against two different azobenzoyl-oestrone derivatives were analysed to investigate both the latency/intensity relationship of the immune response and the influence of antigen presentation on the specificity of the antisera elicited. Elongation of the azo-bridge of the hapten ([p(carboxyphenyl)-azo]-1,3,5[10]- oestratrien-3 ol-17 one) with a short aliphatic chain (4-amino-n-butyric acid) resulted in a marginal increase in the antibody yield, without affecting the time required to attain the maximum titre. The increased flexibility and mobility of the extended azo-bridge was shown to result in the appearance of antisera which cross-reacted with oestrogens with D ring structures different to that of oestrone. Antiserum fractionation by affinity chromatography through a stationary phase exposing the carrier protein determinants, as modified by the addition of the coupling bridge and the phenol ring, resulted in a reduction in its specificity. These findings are discussed with regard to the phenomena underlying the specificity of a polyclonal antiserum.

[Specific antisera to mycobacteria]

Antisera to several Mycobacterium species (M. bovis, M. avium, M. kansasii and M. smegmatis), capable of reacting with homologous antigen diluted not below 1:16000 in the ELISA test, have been obtained. These antisera have been found to cross-react with other Mycobacterium species. Specific antisera to M. bovis, M. avium, M. kansasii and M. smegmatis have been obtained by the multiple exhaustion method on Mycobacterium antigens giving the maximum cross reaction and used for the isolation of antibodies to these Mycobacterium species. In ELISA exhausted antisera produce reactions in the dilution 1:500. Antisera (antibodies) to M. bovis react with the determinant of the antigen with a molecular weight of 25-26 kD, antisera (antibodies) to M. kansasii react with the determinant of the antigen with a molecular weight of 72 kD, those to M. smegmatis react with the determinant of the antigen with a molecular weight of 38 kD and those to M. avium, with the determinant of the antigen with a molecular weight of 16-18 kD.

A protein tyrosine phosphatase expressed within dopaminoceptive neurons of the basal ganglia and related structures

Immunocytochemical and biochemical studies were conducted to characterize a brain-specific protein tyrosine phosphatase, designated STEP for striatal enriched phosphatase. STEP immunoreactivity was most intense in select regions of the CNS receiving a dopaminergic input, and was localized to cell bodies, dendrites, and axonal processes. Western blot analyses of rat brain homogenates revealed a triplet of polypeptides with relative mobilities (M(r)) of 46 kDa, 37 kDa, and 33 kDa enriched within the striatum. Phase separation of protein homogenates by Triton X-114 extraction indicated that this triplet was enriched in soluble but not membrane fractions. Affinity-purified STEP fusion protein exhibited phosphatase activity while a mutated form of the STEP fusion protein (Cys300Ser) showed no demonstrable phosphatase activity.

Generation and characterization of site-directed antisera against an amino-terminal segment of a 55 kDa sperm adhesive glycoprotein from zona pellucida of pig oocytes

ZP3 alpha, a 55 kDa zona pellucida glycoprotein, mediates attachment of boar spermatozoa to zona-encased oocytes. In the study reported here, site-directed antipeptide antibodies were used to probe the topography and biological activity of the amino-terminal domain of this sperm adhesive zona molecule. A synthetic peptide (alpha 8-18) corresponding to an amino-terminal sequence of ZP3 alpha (residues 8-18) was coupled to keyhole limpet haemocyanin (KLH) using either m-maleimidobenzoic acid N-hydroxysuccinimide ester or glutaraldehyde. Male rabbits were immunized with peptide-KLH conjugates using Freund's adjuvant, and antibody production was monitored by ELISA. High-titred antipeptide sera were obtained and further characterized. Western blotting experiments using deglycosylated ZP3 alpha and ZP3 beta core proteins demonstrated reactivity of antipeptide sera with homologous protein. Preincubation of antisera with cognate peptide blocked binding to ZP3 alpha thus confirming site-specific binding of antibodies to the targeted sequence in the intact protein. Anti-KLH-alpha 8-18 sera reacted poorly with fully glycosylated ZP3 alpha, but ZP3 alpha immunoreactivity was markedly enhanced by digestion of polylactosamines with endo-beta-galactosidase, chemical deglycosylation or protein unfolding. Finally, zona-encased pig oocytes were preincubated with the antipeptide sera, washed and exposed to boar spermatozoa. Pretreatment with anti-KLH-alpha 8-18 sera significantly diminished attachment of boar spermatozoa to zonae. These studies demonstrate that the amino-terminal domain of pig oocyte zona protein, ZP3 alpha, is partially occluded, in part by carbohydrate, and that site-directed antipeptide sera targeted to this portion of the molecule can interfere with sperm-zona attachment in vitro.

Enhancement in the safety of immune globulins prepared from high-risk plasma

Hyperimmune gamma-globulins have proven efficacious in the prevention and treatment of viral infections, including those caused by hepatitis A and B viruses, cytomegalovirus, parvovirus. Interest in the prevention and/or treatment of infections caused by human immunodeficiency virus (HIV) has led to clinical trials with anti-HIV immune plasma and purified immune globulin prepared from donors who are actively infected with HIV. The handling and fractionation of this or other infectious plasma requires the construction and operation of virus containment facilities designed to protect fractionation employees and the immediate environment. This requirement would be reduced substantially by applying virucidal procedures prior to or during plasma pooling. We have shown that heating plasma at 56 degrees C for 1 h followed by treatment with 1% tri(n-butyl) phosphate (TNBP) and 1% Triton X-100 for 4 h at 30 degrees C resulted in the inactivation of > or = 10(12.1) tissue culture infectious doses (TCID50) of HIV. With this treatment, the recovery of IgG was 87 +/- 3%. Fractionation of treated plasma by cold ethanol precipitation proceeded normally, and overall recovery, purity, and potency against selected viral markers were unaffected. The additional treatment of plasma with 15 g/l Aerosil for 4 h at 45 degrees C removed 10(4.5) TCID50 of HIV but resulted in substantial IgG losses both prior to and following fractionation. We conclude that potentially infectious plasma can be treated at 56 degrees C for 1 h and by TNBP/Triton X-100 at 30 degrees C for 4 h prior to fractionation. These steps appear sufficient to assure safety and to permit routine fractionation of plasma.(ABSTRACT TRUNCATED AT 250 WORDS)