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At least 19 recordsLinked to original sources

PubMed2001

A novel human homolog of eosinophil major basic protein.

Eosinophil major basic protein (MBP) contributes to host defense and disease pathophysiology. Chromosome 11 contains the genes for human MBP1 (hMBP1) and a second novel MBP, hMBP2, in the centromere to 11q12 region. Interestingly, greater similarity exists between human and murine MBP1 and MBP2 orthologs, respectively, than between hMBP1 and hMBP2, suggesting a gene duplication event prior to the divergence of humans and mice. There is abundant mRNA for hMBP1 in both bone marrow (eosinophils and basophils) and placenta, but hMBP2 mRNA is present only in bone marrow (eosinophils). Comparison of proximal promoters for hMBP2, hMBP1, and murine MBP1 (mMBP1) shows a conserved GATA transcription factor binding site (functionally active in hMBP1). However, whether a C/EBP binding site common to hMBP1 and mMBP1 is functionally conserved in hMBP2 remains unresolved. Similarly, the role of conserved putative IK2 and STAT binding sites in MBP transcriptional control remains unknown. Like hMBP1, hMBP2 is in the eosinophil secondary granule. However, hMBP2 is two-fold less positively charged than hMBP (+8 versus +16 at neutral pH), and this difference may explain hMBP2's similar, but often less potent, in vitro biological activities. Overall, while conservation of hMBP2's amino acid sequence (63% identity with hMBP1) suggests a common function(s) with hMBP1, hMBP2's substantially reduced charge and the existence of the similar mMBP2 argue for additional, unique functions for hMBP2.

Amino Acid Sequence↗

PubMed1990

Cloning and sequence analysis of the human gene encoding eosinophil major basic protein.

Eosinophil granule major basic protein (MBP), a potent toxin for helminths and mammalian cells, is a single polypeptide rich in arginine. The gene, mbp, was cloned and its nucleotide sequence determined. The 3.3-kb gene consists of six exons and five introns, one of which contains an Alu family repeat. The combined exon sequence is similar to previously reported mbp cDNA sequences. The gene is immediately preceded by a putative promoter containing typical TATA and CCAAT boxes. Southern blots indicate that mbp exhibits limited polymorphism.

Amino Acid Sequence↗

PubMed1979

Damage to Trichinella spiralis newborn larvae by eosinophil major basic protein.

Purified eosinophil major basic protein damaged newborn larvae of Trichinella siralis when added to in vitro cultures. Damaged larvae were stiffened, immobile, and showed a granular appearance by light microscopy. Larvae in control cultures and in cultures containing equimolar concentrations of other basic proteins failed to exhibit such damage.

Animals↗

PubMed1988

Biochemical and amino acid sequence analysis of human eosinophil granule major basic protein.

Eosinophil granule major basic protein (MBP) is a relatively low molecular weight cationic (pI greater than 10) protein present in the crystalloid core of the eosinophil granule. Amino acid sequence analysis of this protein was undertaken as part of an analysis of the structural basis of the potent cytotoxic activities of MBP on parasites and mammalian cells. Many conventional sequencing strategies were unworkable because of the unusual amino acid composition of MBP and its insolubility in solutions buffered at neutral pH. Less conventional chemical reactions, including cyanogen bromide-induced cleavage at tryptophan and acid-induced cleavage at aspartic acid, were used successfully to obtain peptides which allowed definition of the amino acid sequence of MBP. Characterization of MBP by reverse-phase high pressure liquid chromatography and two-dimensional gel analysis showed no microheterogeneity that might be attributed to post-translational modifications. Comparison of the MBP sequence with a protein sequence data base showed that MBP has no significant sequence homology with other characterized proteins. The basicity (pI 10.9) and hydrophobicity predicted from the MBP sequence are likely responsible for the observed affinity of this cytotoxic molecule for cell surfaces and some serum proteins.

Amino Acid Sequence↗

PubMed1994

Localization of disulfide bridges and free sulfhydryl groups in human eosinophil granule major basic protein.

Eosinophil granule major basic protein (117 residues) is known to contain free sulfhydryl groups. Here we have located in the amino acid sequence the half-cystine residues present as cysteine, and identified those engaged in disulfide bridges. Of the 9 half-cystine residues, 5 are unpaired cysteines (Cys2, Cys23, Cys42, Cys64, and Cys96), while 4 form disulfides (Cys20-Cys115, and Cys92-Cys107).

Amino Acid Sequence↗

PubMed1989

Pharmacological control of human basophil histamine release stimulated by eosinophil granule major basic protein.

Eosinophil granule major basic protein (MBP) is a 13,800 MW arginine-rich polypeptide that is unique among basic molecules in its ability to stimulate human basophil histamine release. We examined the Ca2+ requirements and pharmacological regulation of MBP-stimulated histamine release. Minimal MBP-induced histamine release occurred in the absence of extracellular Ca2+, whereas addition of 0.1 mM Ca2+ resulted in 70% of the maximum histamine release response. Maximum histamine release required 0.5 to 1 mM extracellular Ca2+. The MBP-induced histamine release was blocked by a calmodulin antagonist and by theophylline and was partially inhibited by an inhibitor of phospholipase A2. Release was unaffected by inhibition of protein kinase C. Basophil pretreatment with pertussis toxin also resulted in a concentration-dependent inhibition of release, suggesting involvement of a GTP regulatory protein in the activation mechanism. Histamine release stimulated by a 13,900 MW poly-L-arginine exhibited a dissimilar pharmacological profile from that of MBP. These results support the non-cytolytic nature of the MBP activation mechanism and identify pharmacological approaches for control of MBP-induced mediator release.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

PubMed1983

Distinctive cationic proteins of the human eosinophil granule: major basic protein, eosinophil cationic protein, and eosinophil-derived neurotoxin.

The human eosinophil granule contains a number of cationic proteins that have been identified and purified to homogeneity, including the major basic protein (MBP), the eosinophil cationic protein (ECP), and the eosinophil-derived neurotoxin (EDN). Because of confusion in the literature regarding the distinctiveness of MBP and ECP, we investigated the immunochemical and physicochemical properties of these purified proteins by electrophoresis on sodium dodecyl sulfate-polyacrylamide gels (SDS-PAGE), by specific double antibody radioimmunoassays (RIA) for MBP and ECP, and by fractionation of acid-solubilized eosinophil granules on Sephadex G-50 columns. Analysis of a mixture of the three purified proteins by SDS-PAGE showed that they migrated as three distinct bands with differing m.w. Comparison by specific RIA for MBP and ECP did not demonstrate any appreciable immunochemical cross-reactivities among the three proteins. Sephadex G-50 column fractions of acid-solubilized eosinophil granules were analyzed by RIA and by SDS-PAGE analysis of individual column fractions. MBP, ECP, and EDN eluted at different volumes from Sephadex G-50 columns as determined by RIA and SDS-PAGE. Soluble extracts of eosinophil granules from patients with the hypereosinophilic syndrome contained between six and 64 times more MBP than ECP on a weight basis. These observations demonstrate that MBP, ECP, and EDN are distinctive cationic proteins of the human eosinophil granule and that eosinophil granules from patients with eosinophilia contain considerably greater quantities of MBP than ECP.

Binding, Competitive↗

PubMed1986

Localization of human eosinophil granule major basic protein, eosinophil cationic protein, and eosinophil-derived neurotoxin by immunoelectron microscopy.

By utilizing the colloidal gold particle technique, we localized eosinophil granule major basic protein, eosinophil cationic protein (ECP), and eosinophil-derived neurotoxin (EDN) in human nasal polyp sections by immunoelectron microscopy. Sections stained with affinity chromatography purified rabbit anti-human major basic protein, and subsequently with gold colloidal particle-goat anti-rabbit IgG, showed gold particles predominantly within granule cores, and not within other eosinophil organelles, plasma cells, mast cells, lymphocytes, or neutrophils. Sections stained with anti-ECP or anti-EDN showed gold particles concentrated over the granule matrix with fewer particles centrally. Control sections treated with preimmunization sera showed no staining of cells or organelles. These results verify the localization of major basic protein to the crystalloid core of the human eosinophil granule and show that ECP and EDN reside in the granule matrix. This technique provides a means of accurately locating the sites of major basic protein, ECP, and EDN deposition and thus of identifying eosinophil degranulation patterns in human disease.

Blood Proteins↗

PubMed2001

Comparative structure, proximal promoter elements, and chromosome location of the human eosinophil major basic protein genes.

Human eosinophil major basic protein (MBP) is strongly implicated as a mediator of disease, especially bronchial asthma. We recently isolated a highly divergent human homologue of MBP (MBPH). Given human MBP's importance in disease and the restricted expression of it and human MBPH, we isolated the 4.6-kb human MBPH gene (HGMW-approved symbol PRG3). Comparisons among the human MBP (PRG2), human MBPH, and murine MBP-1 (mMBP-1; Prg2) genes suggest that the human MBP and mMBP-1 genes are more closely related than either is to the human MBPH gene. Proximal promoters of these three genes show conservation of potential binding sites for IK2 and STAT and of a known GATA site. However, a known C/EBP site is altered in the human MBPH gene's proximal promoter. The human MBP and MBPH genes localized to chromosome 11 in the centromere to 11q12 region. Thus, the human MBP and MBPH genes have diverged considerably, probably following a gene duplication event. Furthermore, the identified conserved and distinct proximal promoter elements likely contribute to the eosinophil-restricted and relatively reduced transcription of the human MBPH gene.

Animals↗

PubMed1989

Antibacterial properties of eosinophil major basic protein and eosinophil cationic protein.

We examined the bactericidal activity of two proteins that are abundant in the cytoplasmic granules of human eosinophils, major basic protein (MBP) and eosinophil cationic protein (ECP). Unlike the human neutrophil's peptide defensins, both MBP and ECP killed stationary phase Staphylococcus aureus 502A in a simple nutrient-free buffer solution. Although MBP also killed Escherichia coli ML-35 with considerable efficacy under these experimental conditions, the in vitro activity of ECP against E. coli was considerably enhanced if mid-logarithmic phase bacteria replaced stationary phase organisms or if the assay medium was enriched with trypticase soy broth. The antibacterial activity of both eosinophil proteins was modulated by incubation time, protein concentration, temperature and pH. A pBR322-transformed derivative of E. coli ML-35 was used to examine the effects of ECP and MBP on integrity of the bacterial inner membrane (IM) and outer membrane. Although both MBP and ECP caused outer and inner membrane permeabilization when nutrients were present, only MBP was effective under nutrient-free conditions. Two proton ionophores (DNP and carbonyl cyanide m-chlorophenyl hydrazone) protected E. coli from the bactericidal effects of ECP but not from MBP. These findings establish that MBP and ECP have bactericidal properties and suggest that these proteins kill E. coli by similar but nonidentical mechanisms marked by an attack on the target cell's membranes. In view of evidence that high concentrations of ECP and MBP exist in cytoplasmic granules whose contents are translocated to phagocytic vacuoles, we suggest that MBP and ECP contribute to the eosinophil's ability to kill ingested bacteria.

Blood Bactericidal Activity↗

PubMed1989

Preparation and characterization of monoclonal antibodies to human neutrophil cathepsin G, lactoferrin, eosinophil peroxidase, and eosinophil major basic protein.

This report describes the production and characterization of five murine monoclonal antibodies that react with granule proteins of human granulocytes. Monoclonal antibody AHN-11 (IgG2a) reacted specifically with neutrophil cathepsin G; no reactivity with the homologous neutrophil neutral proteases, elastase, proteinase 3, or esterase N was detected. Antibodies AHN-9 (IgG1) and AHN-9.1 (IgG2b) each reacted with different epitopes on human lactoferrin, but not with the homologous protein transferrin. Two IgG1 antibodies, AHE-1 and AHE-2, reacted specifically with eosinophils; AHE-1 reacted strongly with eosinophil peroxidase but not eosinophil major basic protein while AHE-2 recognized eosinophil major basic protein but not eosinophil peroxidase. All five antibodies could detect their respective antigens in alcohol-fixed cytospin preparations. These antibodies should be useful for immunolocalization and quantification of their respective antigens as well as for other studies of the roles of these proteins in granulocyte function and differentiation.

Antibodies, Monoclonal↗

PubMed2007

Pregnancy-associated plasma protein A and proform eosinophilic major basic protein in the detection of different types of coronary artery disease.

Kryptor system was proven to be a rapid, standard method for pregnancy-associated plasma protein A and proform eosinophilic major basic protein (PAPP-A/proMBP) complex detection in coronary artery disease (CAD). No age and/or gender differences in 51 controls and 110 stable coronary artery disease (SCAD) patients were found. SCAD patients did not differ from controls and no difference in PAPP-A/proMBP levels with regards to the number of affected vessels was found. In 21 unstable angina pectoris (UAP), in 35 without and 66 with ST elevation acute myocardial infarctions (NSTEMI, STEMI respectively) patients PAPP-A/proMBP levels were increased (P=0.004 and P<0.0005, respectively). PAPP-A/proMBP levels did not correlate with cardiac troponin I (cTnI) in STEMI and NSTEMI patients. PAPP-A/ proMBP increase was more frequent than cTnI (P=0.036) within the early phase of STEMI. In NSTEMI patients PAPP-A/proMBP positivity was present in 50% of cTnI negative cases. Receiver operating characteristic (ROC) analysis revealed the highest diagnostic accuracy of PAPP-A/proMBP (0.919) in STEMI cTnI positive cases. The highest specificity/sensitivity PAPP-A/proMBP levels for particular acute coronary syndrome (ACS) types were 10.65-14.75 mIU/l. Combination of PAPP-A/proMBP with cTnI increases their diagnostic efficacy within the early phase of ACS. Our results suggest that PAPP-A/proMBP complex is involved in processes preceding vulnerable plaque development in ACS.

Acute Coronary Syndrome↗

PubMed1986

Localization of eosinophil cationic protein, major basic protein, and eosinophil peroxidase in human eosinophils by immunoelectron microscopic technique.

An immunoelectron microscopic technique using protein A-gold as a specific marker was used for precise intracellular localization of eosinophil granule proteins. Eosinophils from healthy individuals were isolated in metrizamide gradients. Eosinophil cationic protein (ECP) and eosinophil peroxidase (EPO) were clearly located in the matrix of the large crystalloid-containing granules. In addition, ECP was probably present in the small granules of eosinophils. Major basic protein (MBP) was present in the crystalloid structure of specific granules. This method can be applied in studies of eosinophil degranulation to trace the release of biological effector molecules.

Blood Proteins↗

PubMed1992

Quantitation of eosinophil Major Basic Protein cytotoxicity to rodent respiratory epithelium.

Eosinophil Major Basic Protein (MBP) may be a potent effector in damaging airway epithelium and inducing acute (2-3 h) hyperresponsiveness to agonists in primates. Accordingly, interactions between human eosinophil MBP and guinea-pig airway epithelium were quantitated biochemically. MBP was extracted from human eosinophils and purified by size-exclusion HPLC. This resulted in a single protein band on electrophoresis, which cross-reacted with antisera raised to peptides derived from the predicted sequence of human MBP. This human MBP caused modest, but statistically significant, damage to respiratory epithelium (16.4% increase in efflux of 51Cr from guinea-pig tracheal rings) after 3 h of incubation with 10(-4) M concentration, but not with lower concentrations. These data demonstrates that MBP cytotoxicity to intact epithelium can be rapidly measured in vitro, and suggests that rodent airway epithelium may be relatively resistant to the cytotoxic effects of MBP.

Animals↗

PubMed1993

Prostaglandin secretion by guinea pig tracheal epithelial cells caused by eosinophil major basic protein.

We examined the effect of eosinophil major basic protein (MBP) on prostaglandin (PG) secretion from guinea pig tracheal epithelial (GPTE) cells. Primary cultures of GPTE cells were incubated with 10(-6) M MBP for up to 6 h and then stimulated with 10(-6) M bradykinin (BK). PGE2, 6-ketoprostaglandin F1 alpha (PGF1 alpha), PGF2 alpha, and thromboxane B2 (TxB2) concentrations in media were determined by enzyme-linked immunoabsorbent assay (EIA). Incubation with MBP for 6 h caused secretion of both PGE2 (17,614 +/- 4,416 vs. 1,426 +/- 555 pg/10(6) cells at baseline, P < 0.001, n = 7) and PGF2 alpha (20,303 +/- 5,724 vs. 3,790 +/- 1.075 pg/10(6) cells at baseline, P < 0.002, n = 7). Secretion of PGE2 and PGF2 alpha stimulated by MBP required at least 2 h. Incubation with MBP for 6 h also augmented the subsequent response to BK: PGE2 secretion was 29,215 +/- 6,853 vs. 3,445 +/- 1,041 pg/10(6) cells for BK alone (P < 0.0001), and PGF2 alpha secretion was 25,407 +/- 6,237 vs. 5,213 +/- 1,535 pg/10(6) cells for BK alone (P < 0.0001). MBP did not change 6-keto-PGF1 alpha and TxB2 secretion. Incubation of GPTE cells from seven animals with polylysine, a protein with mass and ion charge similar to MBP, for 2 h, both caused secretion of PGE2 (8,579 +/- 3,244 vs. 788 +/- 419 pg/10(6) cells at baseline, P < 0.01) and augmented the response to BK (12,732 +/- 4,788 vs. 1,653 +/- 680 pg/10(6) cells after BK alone, P < 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

Extracellular deposition of eosinophil major basic protein in orbital histiocytosis X.

Although eosinophils are prominent in orbital lesions of patients with histiocytosis X (Langerhans' cell histiocytosis), little is known of their pathogenic significance in the disease. To determine whether eosinophils degranulate and deposit toxic proteins in orbital histiocytosis X, the authors examined lesions by indirect immunofluorescence for localization of the core granule protein (major basic protein) outside of eosinophils. Four patients with histiocytosis X were studied: three with eosinophilic granuloma and one with Hand-Schüller-Christian disease. Tissue eosinophilia was prominent in all specimens; striking extracellular deposition of eosinophil major basic protein was noted in three patients, and focal deposition was present in the fourth patient. Orbital specimens obtained at autopsy from patients without orbital disease were studied as control specimens; no tissue eosinophilia or deposition of eosinophil major basic protein was observed. These findings indicate that eosinophils likely degranulate in lesions of orbital histiocytosis X and may participate in the pathogenesis of the disease.

Adolescent↗

PubMed2003

Eosinophilic major basic protein and interleukin-5 in eosinophilic myositis.

To determine whether eosinophils play a critical role in muscle fiber damage in patients with eosinophilic myositis (EM). We investigated expression of eosinophilic major basic protein (MBP) and interleukin (IL)-5 at the protein and mRNA levels in muscle biopsies from three patients with idiopathic EM. MBP deposits were found on the surface of eosinophils and muscle fibers surrounded by the eosinophils. Reverse transcriptase-polymerase chain reaction analysis showed increased IL-5 expression in EM muscle but not in control muscle. These results suggest that IL-5 induces local accumulation of eosinophils and their release of MBP. The secreted proteins adhere to the muscle fiber membrane, resulting in muscle damage.

Adult↗

PubMed1995

Identification of angiotensinogen and complement C3dg as novel proteins binding the proform of eosinophil major basic protein in human pregnancy serum and plasma.

In sera from pregnant women, pregnancy-associated plasma protein-A (PAPP-A) circulates as a disulfide-bound complex (approximately 474 kDa) with the proform of eosinophil major basic protein (proMBP) (Oxvig, C., Sand, O., Kristensen, T., Gleich, G. J., and Sottrup-Jensen, L. (1993) J. Biol. Chem. 268, 12243-12246). We have produced monoclonal antibodies (mAbs) against the PAPP-A.proMBP complex and established a radioimmunoassay utilizing a mAb recognizing the PAPP-A subunit. Surprisingly, serum levels of proMBP exceed those of PAPP-A four to 10-fold on a molar basis throughout pregnancy. This result prompted an investigation of the status of proMBP in pregnancy. Using a proMBP-specific mAb two novel proMBP complexes have been isolated by chromatographic techniques. Based on sequence analysis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and reaction with specific antibodies, one is shown to be a 2:2 disulfide-bound complex (approximately 200 kDa) between proMBP and angiotensinogen. The other is a 2:2:2 complex (approximately 300 kDa) between proMBP, angiotensinogen, and complement C3dg. Circulating proMBP in pregnancy is thus present in three types of complexes. These results suggest that specific interactions between the complexed proteins occur in pregnancy, and the possibility is raised that their interactions are important in the pathophysiology of pregnancies associated with hypertension.

Amino Acid Sequence↗