The presence of creatine kinase (CK)-immunoreactive neurons in the zona incerta and lateral hypothalamic area of the mouse brain

Immunohistochemical studies of mouse brain using antibody to creatine kinase (CK) revealed a distinctive group of positive neurons in zona incerta and lateral hypothalamic area. These CK-immunoreactive neurons showed an intense, granular staining pattern, while other positive neurons distributed in other brain areas showed a weak, diffuse pattern.

Monoclonal antibody studies of creatine kinase. Antibody-binding sites in the N-terminal region of creatine kinase and effects of antibody on enzyme refolding

(1) The binding sites of two monoclonal antibodies, CK-2A7 and CK-5H5, have been located to a 60-amino-acid sequence in the N-terminal region of creatine kinase (CK) by the use of chemical cleavage with formic acid (which cleaves proteins at Asp-Pro bonds) and cyanogen bromide (which cleaves at Met residues). (2) A simple method for preparing chemically-cleaved fragments of proteins for electrophoresis and Western blotting is described. (3) Binding studies with CK preparations from different animal species show that single amino acid changes at residues 39 or 82 prevent binding of CK-2A7 and CK-5H5 respectively. We suggest that Lys-39 and Glu-82 form parts of the binding sites on CK for the two monoclonal antibodies. The two sites lie in variable regions at each end of a highly-conserved sequence (residues 46 to 79) and are inaccessible to antibody in the native enzyme. (4) One of the antibodies, CK-2A7, inhibits the refolding of CK to native enzyme after denaturation by urea.

Humoral response in Treponema pallidum-infected guinea pigs. II. Circulating immune complexes and autoimmune responses

Guinea pigs of inbred strain 2 and of a strain deficient in complement component 4 (C4D) responded to intradermal infection with Treponema pallidum by production of antibodies to treponemal antigens, normal rabbit serum proteins, fibronectin, and creatine kinase and with formation of circulating immune complexes (IC). IC started to appear at low concentrations 1 mo after infection and increased between 3 and 5 mo post-infection. Antibodies to fibronectin appeared after the second month but were not detectable 30 days later. Antibody activity to creatine kinase was detectable at the fourth month and became significantly higher at 5 mo post-infection. Reinoculation with a dose similar to that used for primary infection caused a significant increase in all antibodies and IC. Dissociation products of IC formed after primary infection consisted predominantly of treponemal antibodies and antigens, whereas IC detected after reinfection consisted predominantly of antibodies and normal rabbit serum proteins. Antibodies to fibronectin and creatine kinase are considered autoantibodies, and the underlying mechanism responsible for their production in syphilis is discussed.

Reassessment of creatine kinase BB as a marker for cancer of the prostate, breast, and lung

We used an enzyme-linked immunoabsorbent assay to measure creatine kinase (CK; EC 2.7.3.2) BB in the sera of 58 cancer patients. A pre-incubation step with an anti-CK-M antibody-coated bead removed M chain components, and CK-BB was quantified with use of an anti-CK-B antibody-coated tube. No cross reactivity was observed with mitochondrial CK or CK-MM; CK-MB cross reacted slightly (1.6%). Macro CK type 1 was measured as CK-BB. Average analytical recovery of purified CK-BB added to serum was 97.7%. Although the enzyme activity of CK-BB is labile, our studies show that this protein is antigenically stable for 12 months when stored frozen. The upper limit of normal for CK-BB concentration was 0.3 micrograms/L (95th percentile, n = 25). Of the 20 cases of breast cancer of various stages, none showed any increases of serum CK-BB. Only two of 18 patients with prostatic carcinoma (stage D), and two of 10 patients with oat-cell carcinoma of the lung had increased concentrations of CK-BB in the serum. Ten patients with squamous cell cancer of the lung had normal concentration of the enzyme. Thus the CK-BB isoenzyme is not frequently increased in cancers of the prostate, lung, and breast, and it has little apparent value as a tumor marker for these diseases.

Differentiation of creatine kinase MB and IgA-linked BB isoenzymes on electrophoresis

IgA-linked creatine kinase (CK, EC 2.7.3.2) is a macro CK type 1 isoenzyme that has an identical electrophoretic mobility to CK-MB. Its presence has the potential of causing misdiagnosis of myocardial infarction. Mixing anti-CK-B antiserum with the sample prior to electrophoresis did not unequivocally distinguish between the two isoenzymes. Similarly, anti-human IgG and IgM antibodies were also ineffective. However, the IgA-linked isoenzyme band was removed by anti-human IgA antiserum. While anti-CK-M antibodies did not affect the electrophoretic mobility of IgA-linked CK-BB, the antibody eliminated both the CK-MB and CK-MM bands. Thus, specific anti-IgA and anti-CK-M antibodies may be used to establish the presence of the myocardial isoenzyme.

Kinetic immunochemical method for the simultaneous quantification of creatine kinase isoenzymes

We describe the development and evaluation of a kinetic immunochemical method for the simultaneous quantification of isoenzymes. Specifically, we use the inhibition of the M subunit of creatine kinase (CK; EC 2.7.3.2) by antibodies to quantify isoenzymes CK-MM and CK-MB in serum matrices. Nonlinear least-squares data-processing is used to compute the enzyme activities from the time-dependent response of absorbance vs time. Variables affecting the method, namely temperature, substrate concentration, and antibody concentration as well as their interactions, are evaluated by using response-surface methodology. For several concentrations of CK-MM and CK-MB in the range of diagnostic significance, least-squares fits of computed (y) vs expected (x) values yielded equations of y = 0.98x + (2.0 X 10(-5)) s-1 for CK-MM and y = 1.04x - (4.6 X 10(-5)) s-1 for CK-MB for rates between 0 and 3.5 X 10(-3) s-1 (CK-MM) and 0.5 X 10(-3) s-1 (CK-MB). The equations for comparison of kinetic results (y) with results by a kit method (x) were y = 0.97x + (6.5 X 10(-5)) s-1 for CK-MM and y = 1.02x + (4.3 X 10(-5)) s-1 for CK-MB. Pooled day-to-day relative standard deviations (CVs) for the kinetic method were 4.1% and 2.8% for CK-MM and CK-MB, respectively.

Reconstitution of functionally active antibody directed against creatine kinase from separately expressed heavy and light chains in non-lymphoid cells

We report here for the first time reconstitution and secretion of functionally active antibody in non-lymphoid cells. Expression vectors for the light and the heavy chain of a monoclonal antibody directed against creatine kinase (EC 2.7.3.2) were introduced into COS and CHO Chinese hamster ovary dhfr- cells. Introduction of the expression vectors separately gave rise to immuno-reactive material in the culture supernatants, but only cotransfection of the expression plasmids resulted in secretion of protein with immuno-reactivity against antibodies directed against mouse heavy and light chains as well as specific antigen-binding affinity, as determined by enzyme-linked immunosorbent assay. Secreted kappa and gamma chains from reconstituted antibody were characterized by immunoadsorption and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. In COS cells, reconstituted antibody was transiently secreted; cotransfection of kappa and gamma chain expression plasmids with a dihydrofolate reductase (DHFR)-expression plasmid into CHO dhfr- cells gave rise to stable transformants secreting functionally active antibody.

Expression of antibody cDNA in murine myeloma cells: possible involvement of additional regulatory elements in transcription of immunoglobulin genes

Expression vectors for cDNA of the kappa and gamma 1 chains of a monoclonal antibody directed against creatine kinase were introduced into murine myeloma cells. Kappa and gamma 1 cDNA were either under the control of the SV40 early promoter or of the cognate promoters and enhancers of the light- and heavy-chain genes. Secretion of immuno-reactive kappa and gamma 1 chains into the culture medium was demonstrated with the SV40 promoter as well as with the cognate promoters. Expression of gamma 1 cDNA with the SV40 early promoter was about twice as high as with the heavy-chain promoter and enhancer. Expression of kappa cDNA under the control of the SV40 early promoter was about 17 times higher than with the light-chain promoter and enhancer. These expression levels were compared to those of a genomic immunoglobulin (Ig) kappa determinant, including introns. Such an entire kappa gene led to expression of the light chain at levels double those with the kappa cDNA construction using the SV40 promoter and about 35 times as high when using kappa cDNA and the cognate promoter and enhancer. This result might indicate that, besides the cognate promoter and enhancer elements, other intragenic elements are involved in the regulation of Ig expression. However, the SV40 early promoter seems to be able to compensate for the absence of these postulated regulatory elements probably located in the introns.

Cloning and nucleotide sequence of heavy- and light-chain cDNAs from a creatine-kinase-specific monoclonal antibody

Determination of creatine kinase isoenzymes by inhibition assay is a useful tool for the diagnosis and monitoring of myocardial infarction. We have established several mouse hybridoma lines secreting monoclonal antibodies with creatine kinase M-subunit inhibitory capacity. One of the monoclonal antibodies (MAK33) inhibits creatine kinase-MM by 80% without influencing the activity of creatine kinase-MB. A combination of two monoclonal antibodies increased the inhibition of creatine kinase MM up to 99.4%. Poly(A) + RNA of hybridoma cells secreting MAK33 was isolated and used for cloning cDNA of both heavy and light chains of this antibody. Full-length cDNA clones were obtained by hybridization with gamma 1 and kappa constant region cDNA probes. The complete nucleotide sequences from the variable regions including signal peptide and part of the 5'-untranslated regions have been determined.

Detection of cerebral injury after total circulatory arrest and profound hypothermia by estimation of specific creatine kinase isoenzyme levels using monoclonal antibody techniques

New 2-site labeled monoclonal antibody techniques were used to measure serially plasma levels of brain-type creatine kinase (CK-BB), heart-type creatine kinase (CK-MB) and muscle-type creatine kinase (CK-MM) during a 20-hour postoperative period in 24 infants after deep hypothermia and total circulatory arrest used in pediatric cardiac surgery. A control group of 7 children undergoing cardiovascular procedures without extracorporeal circulation or circulatory arrest also were studied. There were marked increases in CK-MB and CK-BB levels in the circulatory arrest group but not in the closed group. CK-BB increased from 3.2 +/- 0.5 to 27 +/- 10 ng/ml and CK-MB from 5.9 +/- 2.1 to 137 +/- 12 ng/ml. The CK-MM concentrations increased from 299 +/- 91 and 194 +/- 49 ng/ml to 1,220 +/- 274 and 1,322 +/- 142 ng/ml in the closed and circulatory arrest groups, respectively. Peak levels of CK-MB and CK-BB occurred an average of 133 and 127 minutes, respectively, after reperfusion. The half-time of CK-BB differed significantly from that of CK-MB (149 +/- 15 vs 359 +/- 20 minutes). The arrest time had a more marked effect on CK-BB concentration than on CK-MB and CK-MM concentrations. Arteriointernal jugular venous concentration differences were consistently negative for CK-BB in the circulatory arrest group, but not for CK-MM and CK-MB.(ABSTRACT TRUNCATED AT 250 WORDS)

[Macro-CK type 1: a methodological study approach and its clinical significance]

Description of an analytical procedure in order to show the atypical-CK carriers that simulate an abnormal raising of CK-MB circulating levels in dosages for immune inhibition. This procedure was applied to two samples taken from patients of such a type, immune form neoplastic and cardiac pathology. A systematic dosage of a "real" MB isoenzyme is desirable in all the cases of very raised CK-MB activity.

Clinical significance and characteristics of creatine kinase-immunoglobulin complexes in sera from patients with malignant tumors

Creatine kinase (CK, ATP: creatine N-phosphotransferase, EC 2.7.3.2) and immunoglobulin complexes were detected in 27 of 234 (11.5%) patients with malignant tumors. The complexes electrophoresed between CK-MM and the sample application point. The positive rate was significantly higher than rates in patients with benign diseases, or in healthy adults (p less than 0.001). Primary malignancies of the 27 patients were colon 8, gastric 6, pancreatic 4, liver 5, pulmonary 3 and mammary 1. As 22 of the 27 patients had a recurrence or a metastasis and the mortality rate of the positive group 6 mth after the tests was high (85%), most of the 27 patients had advanced tumors. Thus, the CK-immunoglobulin complexes seem to be a prognosticator of patients with advanced tumors. The classes and types of immunoglobulins in the complexes were IgA lambda, 7; IgA kappa lambda, 5; IgA (types of the light chain were not identified), 4; IgA/G kappa, 1; IgA/G lambda, 3; and IgA/G kappa lambda, 7. The molecular sizes of the complexes were 384,000 +/- 22,000 (mean +/- 1 SD). The results of recombination assays using IgA isolated from the complexes of 4 patients suggested that the complexes in the patients' sera were mitochondrial CK-IgA. Non CK-M subunit activities of the positive group were 58 +/- 40 U/l (mean +/- 1 SD) and they were significantly higher than those of the complex negative group of tumor patients (p less than 0.01). This is probably the first report of detection of mitochondrial CK-IgA complexes.

Highly sensitive enzyme immunoassay for human creatine kinase MM and MB isozymes

A sensitive enzyme immunoassay system for measurement of MM and MB forms of human creatine kinase (CK) was developed using purified monospecific antibodies to the M subunit and to the B subunit of CK. The CK-MM assay system consisted of polystyrene balls with immobilized F(ab')2 fragments of anti-M and the same antibody Fab' fragments labeled with beta-D-galactosidase from Escherichia coli. The CK-MB was assayed with the polystyrene balls with either antibody (anti-M or anti-B) F(ab')2 fragments and the other antibody (anti-B and anti-M, respectively) Fab' fragments labeled with galactosidase. The assays were highly sensitive and 3 pg of CK-MM and CK-MB were measurable. The CK-MM assay was specific to the M subunit of creatine kinase, and it cross-reacted about 15% with CK-MB, but not with CK-BB. The CK-MB assay did not cross-react with CK-MM nor CK-BB. Therefore, concentrations of CK-MM could be estimated by subtracting the cross-reacting values of CK-MB. Coefficients of variation in within-run and between-run precision studies for serum CK-MM and CK-MB were less than 9%. Serum levels in healthy adults of various ages (16-59 yr old) were ranged from 35.2-132 ng/ml for CK-MM and from 0.40-1.77 ng/ml for CK-MB. There was apparently no statistical significance among the sex- and age-related differences. Concentrations of CK-MM and CK-MB in various human tissues were also determined. The CK-MM was present abundantly in the heart and the tissues composed of striated muscles (skeletal muscle, diaphragm and proximal esophagus). The CK-MB was distributed not only in the heart but also in the striated muscle tissues at a relatively high level.

Macro CK type 1 as a marker for autoimmunity in coronary heart disease

In a group of 3000 hospital patients the prevalence of immunoglobulin bound creatine kinase (macro CK type 1) was 4.3%. The relative frequency was greater in the older age categories. The highest prevalence was found in patients with rheumatic and cardiac diseases. In a group of 556 cardiac patients selected for coronary angiography a prevalence of 13.8% was observed. No significant correlation was obtained between the findings of the coronary angiography and the activity of macro CK type 1. CK MB results determined by ion-exchange or immuno-inhibition techniques in macro CK type 1 positive patients are falsely positive. Macro CK type 1 may be seen as an antigen-antibody complex against CK BB, which originates at least partly from the vascular wall.

Macro-creatine kinase type 1. Immunological studies in 14 patients with comments on clinical significance

Circulating autoantibodies directed at creatine kinase (CK) BB isozyme are detected in plasma in the form of an immune complex (immunoglobulin CK BB) termed macro-CK type 1. Fourteen patients presented a falsely elevated CK MB isozyme fraction as measured by the immunoinhibition method; they were found to have IgG-CK BB complexes, which was considered to be indirect evidence of circulating anti-CK BB autoantibodies. No evident clinical association between the detection of this autoantibody in complexed form and autoimmune disease could be established, there was no significantly increased incidence of other autoantibodies, and there was no specific alteration in immunoglobulin and complement levels; however, the HLA haplotype A1,B8,DR3, which is known to be associated with autoimmunity, was present in five patients.

Direct measurement of creatine kinase-MB activity in serum after extraction with a monoclonal antibody specific to the MB isoenzyme

Fusion of splenocytes from A/J mice immunized by creatine kinase (EC 2.7.3.2)-MB isoenzyme (CK-MB) with SP2/0-Ag14 myeloma cell line generated hybridomas producing monoclonal antibodies specific to CK-MB. One of these monoclonal antibodies ("Conan-MB") was used to develop a direct assay for CK-MB activity. In the assay, serum is incubated for 30 min at room temperature with "Conan-MB" immobilized on latex beads. The beads are then washed, and CK-MB activity bound to the antibody is measured after incubation with CK enzyme reagent for 30 min at 37 degrees C. Results with the assay correlated well (r = 0.997) with those for CK-MB concentration as measured by a two-site immunoassay. Neither CK-MM, CK-BB, mitochondrial CK, nor a hemolysate of erythrocytes interfered. Use of this unique monoclonal antibody allows rapid, precise, and direct determination of CK-MB activity.

Autoantibodies to creatine kinase in rabbits infected with Treponema pallidum

Sera from rabbits infected intratesticularly with Treponema pallidum (Nichols) for 30 days were examined for autoantibody reactivity against muscle and testis extracts by Western immunoblotting. Syphilitic sera (30 day) reacted with an autoantigen of 43,000 daltons in muscle extracts. The antigen was shown to be creatine kinase (CK). Studies with the use of an anti-CK ELISA showed that the autoantibody to CK first appeared 3 wk after infection, declined by 7 wk infection, and was absent in rabbits "mock"-infected with heat-killed T. pallidum. CK activity was not detected in sonicated or intact, washed T. pallidum, suggesting that the antibody was not produced in response to treponemal CK.

Influence of autoantibodies to creatine kinase-BB on assays for MB isoenzyme

We describe the influence of autoantibodies that bind creatine kinase BB (CK-BB) on the methods for MB isoenzyme. If these autoantibodies are present in patients' sera, they cause the formation of macro CK type 1 (immunoglobulin-linked CK-BB). In some of these cases they can bind not only endogenous CK-BB but also CK-MB without significantly affecting enzyme activity. Although these antibodies show distinctly less affinity for CK-MB than for CK-BB, they nevertheless bind CK-MB in these particular sera, because their concentration exceeds that of CK-BB isoenzyme. If a person with such autoantibodies has an acute myocardial infarction, the immunoinhibition method for CK-MB, which does not discriminate between CK-MB and CK-BB, will recognize the increase and peak of CK-MB with time, although persistent macro CK activity will be superimposed on the typical isoenzyme pattern. However, isoenzyme electrophoresis and recently introduced immunoenzymometric assays for CK-MB in these cases may be less sensitive for detecting myocardial infarctions, because the typical increase in CK-MB activity may be identified later in the progression of symptoms, or even be missed.

Enzyme kinetics of a highly purified mitochondrial creatine kinase in comparison with cytosolic forms

Mitochondrial creatine kinase (CK) purified from canine myocardium showed a single protein band on SDS-PAGE and was free of MMCK. Its amino acid composition was different than MMCK or BBCK and did not react to antiserum to MMCK or BBCK. Using purified mitochondrial, MM and BBCK, the velocity of reaction (V) was estimated for creatine phosphate (CP), creatine (C), adenosine triphosphate (ATP) and adenosine diphosphate (ADP) over a wide range of concentrations including those at Vmax. The values for Km (mM/L) derived from Lineweaver-Burke plots are shown: (Table: see text). The affinity of mitochondrial CK for C is much greater than MMCK which is compatible with the energy shuttle hypothesis, namely ATP is converted by mitochondrial CK to CP, and then diffuses to the myofibril for conversion to ATP for utilization.

The stability of creatine kinase isoenzymes studied with two-site monoclonal antibody assays

The stability of human creatine kinase isoenzymes was investigated under different storage conditions using specific two-site monoclonal antibody assays. In Tris-HCl buffer pH 7.5 or barbitone buffer pH 8.1 containing 5 g/L bovine serum albumin, the isoenzymes appeared to be stable for up to 3 weeks at 4 degrees C but suffered a partial subunit dissociation and random reassociation after freeze-thawing; this dissociation was more pronounced as a result of freezing at -20 degrees C rather than at -70 degrees C. In contrast, creatine kinase isoenzymes stored in serum were stable at both 4 degrees C and following freeze-thawing. High levels of heart type creatine kinase in serum showed only minor subunit hybridisation even after 12 h at room temperature. We conclude that in practical clinical situations, subunit hybridisation in serum samples is negligible. We recommend however, that isoenzyme standards for use in either two-site assays or radioimmunoassays should be stored frozen in normal serum from which endogenous creatine kinase isoenzymes have been previously removed.

Expression of a rat brain creatine kinase-beta-galactosidase fusion protein in Escherichia coli and derivation of the complete amino acid sequence of rat brain creatine kinase

Expression of a rat brain creatine kinase (CKB)/beta-galactosidase fusion protein in Escherichia coli has allowed isolation of a rat CKB cDNA clone by direct antibody screening of a rat brain gamma gt11 expression library. This clone is 1416 bp long and includes 202 bp of 3'-untranslated region and 29 bp of 5'-untranslated region. The coding sequence of this clone has enabled us to deduce the complete amino acid (aa) sequence of rat CKB protein.

Inadequacy of traditional ELISA for screening hybridoma supernatants for murine monoclonal antibodies

Hybridomas producing anti-creatine kinase (CK) and anti-lactate dehydrogenase (LDH) antibodies were screened by enzyme linked immunosorbant assay (ELISA) with antigen coated onto plastic wells. Out of seven antibodies positive for each isoenzyme of CK, four antibodies failed to bind to the radiolabeled antigen in solution phase radioimmunoassay (RIA) or native antigen in competitive ELISA. Moreover, out of nine antibodies shown reactive with LDH-1 and seven antibodies binding to LDH-5 by ELISA, not a single antibody bound to either radiolabeled or native antigen in solution. Our results along with other recent studies strongly suggest that antigen conformation on solid phase may frequently be different from in solution and that screening by ELISA in which antigen is attached to solid phase is often inappropriate for determining the presence of useful monoclonal antibodies.

Comparative analysis of rat uterine estrogen-induced creatine kinase with monoclonal antibodies

Monoclonal antibodies were generated against rat uterine estrogen-induced protein--creatine kinase (CK-EIP)--and two (MAb-28 and MAb-78) were studied. These antibodies were IgM but differed in their complementary antigenic determinants both of which were detectable on denatured but not on native CK-EIP. MAb-28 reacted with other CK-BBs but not with CK-MMs whereas MAb-78 reacted with both types of CKs. A measurement of antigenicity with the monoclonal antibodies under calibrated conditions showed differences among the CKs, notably between CK-BB from rat brain and CK-EIP when both were probed with MAb-28. The antigenicity of CK-BB (rat brain) was significantly lower than that of CK-EIP, indicating that the former either expresses less copies of the determinant recognized by MAb-28 than CK-EIP does, or possesses a determinant which interacts with the antibody with lower affinity. The monoclonal antibodies should help elucidate structure-function relationships in CK-BB and CK-EIP molecules, their anatomic distribution and their physiologic, pathologic and experimental variations in relation to gene expression induced by sex hormones.