Purification and partial characterization of two major allergens from the house dust mite Dermatophagoides pteronyssinus

Two major allergens of the house dust mite, Dermatophagoides pteronyssinus (Dp), were purified, and their molecular weight and isoelectric points (pIs) were determined. Dp 42 was purified from an acetone-precipitated mite-excrement extract by a combination of hydrophobic interaction chromatography on phenyl Sepharose and copper-chelate chromatography. The molecular weight was determined to be 18,000 and 25,000 to 30,000 by gel filtration (G-75) and sodium dodecyl sulphate-polyacrylamide gel electrophoresis, respectively, and pI values of 4.6, 5.6, and 6.6 were obtained by sucrose gradient isoelectric focusing (IEF). These values correspond well with those described for the identical allergen, P1. The pI 6.6 variant was considerably enriched in the purified material. Dp 42 constituted 6.4% of the dry weight of a reference whole mite-culture extract. Dp X was obtained partially purified by gel filtration (G-75), ammonium sulphate precipitation, and hydrophobic interaction chromatography. The molecular weight was 18,000 to 20,000 by gel filtration and sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Multiple pIs in the range 5 to 7 were found by sucrose gradient IEF and crossed IEF. The two purified allergens carried clearly distinct activities toward human IgE and appeared as potent allergens in crossed radioimmunoelectrophoresis, RAST, and RAST inhibition.

[Effect of celiprolol compared to propranolol on thyroid metabolism]

In series of 20 patients suffering from atrial arrhythmias, hypertension or hyperkinetic heart syndrome in euthyroid subjects the effect of the new cardioselective beta-blocker celiprolol was examined when orally administered in doses of 300 mg per day against propranolol in a dosage of 160 mg per day. Celiprolol caused a significant reduction (p less than 0.01) of both systolic and diastolic blood pressure while propranolol showed simply a marked decrease in systolic blood pressure. A significant decrease in heart rate was observed with both drugs (p less than 0.01). TT3 and TT4 decreased only slightly when administering either celiprolol or propranolol. A further not significant drop in FT4 due to celiprolol is contrasted to a similarly not significant increase in FT4 when administering propranolol. A striking decrease in FT3 was induced by both drugs, although in the case of celiprolol this reduction became apparent only within a period of 3 weeks. Since only in cases of hyperthyroidism the number of beta-receptors has increased, the reduction of 5'deiodinase is possibly not so pronounced in euthyroidism. In this way an explanation may be found for a mild inhibition of conversion and a consequently missing increase in RT3. Neither celiprolol nor propranolol caused significant changes of laboratory findings, especially when considering triglycerides and creatinine values. Side effects could be lessened in nearly all cases and deterioration was not observed so that therapy never had to be discontinued. Celiprolol has to be considered as a further favourable cardioselective beta-blocker with intrinsic sympathicomimetic activity, causing a reasonable reduction in blood pressure and heart rate and moreover a propranolol-like effect in the peripheral metabolism of thyroid hormones in euthyroid patients.

Activity of allergenic proteins from Dermatophagoides pteronyssinus. Comparison of crossed radioimmunoelectrophoresis (CRIE) and histamine release from washed leukocytes

Two purified allergens from Dermatophagoides pteronyssinus, Dp 42 (identical to P1) and Dp X were studied for their ability to induce histamine release from washed leukocytes and to bind to IgE antibodies from the serum of 27 mite-sensitive children. Almost all patients were demonstrated to be sensitive to both proteins by both assays. Dp 42 was found to have the highest allergenic activity, releasing histamine from leukocytes at a median concentration 10 times lower than for Dp X. There was a positive correlation between basophil sensitivity to both proteins and allergen specific serum IgE concentrations.

Identification and clinical significance of allergenic molecules of cat origin. Part of the DAS 76 Study

Freeze-dried extracts from cat dander and the corresponding rabbit antibodies were used for establishing the CIE reference pattern for cat dander extracts. Anti-Cat Ag 1 and anti-cat albumin were used for identification of the corresponding antigens. CRIE on sera from selected groups of American and Danish cat-allergic patients demonstrated antigen-specific IgE binding to 10 of 15 cat dander antigens (Cat Ag 1 being the major allergen). Only minor differences were found between the two groups. Four of these allergens were serum proteins. Variable amounts of many of the 10 allergens were measured by QIE in saliva, serum, urine and three cat pelt extracts. However, extremely wide ranges for content of the serum allergens and the non-serum allergens were found. This was exemplified by an albumin/cat Ag 1 ratio between 1 and 400, smallest in cat dander. Immunoabsorption using anti-cat dander, anti-cat albumin and anti-Cat Ag 1 indicated that the anti-cat dander, anti-cat albumin, and the anti-Cat Ag 1 absorbed approximately 90%, 25%, and 56%, respectively, of the dander RAST activity, and 87%, 11%, and 45%, respectively, of the saliva RAST activity, confirming the major importance of Ag 1. It is concluded that cat allergenic extracts should contain only modest amounts of serum albumin and other serum-derived antigens and that any relevant standardization must include quantification of at least Cat Ag 1 and cat albumin.

The occurrence of indoor allergens in Saudi Arabia

Investigations on indoor airborne allergens in Saudi Arabia were performed by mold cultures and dust analyses by counter-current immunoelectrophoresis. Twenty fungal genera were isolated, with Aspergillus as the most often encountered. Most of the dust-bound fungi found are ubiquitous and common. Antibodies against Dermatophagoides pteronyssinus, cat- cow- and rat dander, and Cynodon dactylon pollen were used in the dust analyses. Animal antigens were found in five of the ten dust samples. House dust mites were extraordinarily rare. Pollen of Cynodon dactylon (Bermuda grass) was present in nearly all the samples, and in a concurrent clinical study this antigen was found to be the most common cause of perennial rhinitis.

The primary structure of rat liver cellular retinol-binding protein

The complete amino acid sequence of a cellular retinol-binding protein (CRBP) has been determined for the first time. The primary structure of rat liver CRBP was elucidated by analyses of cyanogen bromide fragments and peptides obtained by tryptic and thermolytic digestions. The single polypeptide chain of rat CRBP consists of 134 amino acid residues. Under reducing conditions, CRBP exists as a monomer, but, in the absence of reducing agents, dimers and multimers of the protein emerge. This is explained by the observation that CRBP contains 3 cysteines, one of which seems to be highly reactive. Whether CRBP contains a disulfide bond is not yet established. The present data extend the previously described homology between CRBP and a family of low molecular weight proteins, all members of which may bind hydrophobic ligands. Since some of these proteins apparently display intracellular transport functions, a similar role for CRBP is envisaged.

The primary structure of rabbit and rat prealbumin and a comparison with the tertiary structure of human prealbumin

The primary structures of rabbit and rat prealbumin have been determined. The amino acid sequence of rabbit prealbumin was determined by analyses of peptides obtained by trypsin and Staphylococcus aureus protease digestions. The rat prealbumin sequence was deduced by analyses of tryptic peptides as well as by nucleotide sequencing of cDNA clones. Both amino acid sequences contain 127 amino acid residues, the same as human prealbumin. Pairwise comparisons show that the three sequences are more than 80% identical. All three prealbumins were found to display significant sequence homology with human thyroxine-binding globulin. A comparison of the primary structures of the prealbumins with the tertiary structure of human prealbumin shows that amino acid replacements are preferentially located at the surface of the molecule and in the loops connecting the beta-strands. The locations of the replacements are discussed as regards the different molecular interactions in which prealbumin is involved.

Standardization of Dermatophagoides pteronyssinus: assessment of potency and allergen content in ten coded extracts

As part of the studies to establish an international reference preparation of Dermatophagoides pteronyssinus allergens, ten coded extracts of this mite were assessed in four laboratories. The extracts were compared for total potency using direct RAST, RAST inhibition and quantitative skin tests, and also for composition and major allergen content using crossed immunoelectrophoresis, crossed radioimmunoelectrophoresis, rocket immunoelectrophoresis and radioimmunoassay. In addition, the source materials were examined by light microscopy, and the extracts were examined for the presence of proteins/allergens derived from the culture media. To help with standardization, a new reference pool of sera from patients allergic to D. pteronyssinus was also established (National Institute of Biological Standards and Control, NIBSC, 82/528). The results showed that techniques are available for measurements of potency and allergen content. In several of the extracts, culture medium derived allergens and antigens were demonstrated. It also became clear that extracts varied not only in their total potency but also in the distribution of the identifiable allergens. In particular, extracts derived from isolated mites contained more AgX and/or Ag 23 relative to their content of antigen P1 (= Ag42). These studies lead to the choice of an extract for an international reference preparation (NIBSC 82/518) and helped to establish the methods used subsequently in the international collaborative study.

A reference allergen preparation of the house dust mite D. pteronyssinus, produced from whole mite culture--a part of the DAS 76 study. Comparison with allergen preparations from other raw materials

A D. pteronyssinus whole culture allergen preparation contained 49 antigens as revealed by crossed immunoelectrophoresis (CIE), using polyspecific rabbit antibodies. Crossed radio-immunoelectrophoresis ( CRIE ) with sera from 30 patients revealed nine allergens, antigens 42, X, Y and 23 (in rank order) showing the most frequent and intense IgE-uptake. Nine antigens originated from the culture medium (human dander + yeast), but none of these gave rise to specific IgE-uptake. Extremely few and weak reactions were observed in radioallergosorbent (RAST) with 129 sera, using media extracts on the discs. Purified mite body extract (PMB) contained less ag 42 and more ag Y and ag 23 than whole mite culture extract ( WMC ), whereas an acetone-extracted mite excreta preparation (AML) contained 5 times more ag 42, but was devoid of ag Y and ag 23. Ag X was present in all preparations. The RAST-inhibitory potency of PMB was best correlated with the content of ag X. Preparations with properties similar to WMC and PMB were judged as suitable for clinical application.

Complex formation of class I transplantation antigens and a viral glycoprotein

Indirect immunoprecipitations of labeled glycoproteins from the adenovirus-transformed rat cell line A2T2C4 and from adenovirus-infected HeLa cells revealed that the class I major histocompatibility antigens co-precipitated with the viral E19 protein. The degree of co-precipitation was highly dependent on the antiserum used. The identity of the co-precipitated components was verified by peptide mapping and radiochemical amino acid sequencing. Cell-free translation of mRNA for the E19 protein and the class I antigen heavy chains demonstrated that the E19 protein-class I antigen interaction is an inherent property of the participating components. In intact cells the virus protein and the transplantation antigens form large complexes, held together by weak, noncovalent interactions.

The complete nucleotide sequence of the I-E alpha d immune response gene

We have isolated and sequenced the complete murine I-E alpha immune response gene of the H-2db haplotype. The I-E alpha d gene consists of 5300 basepairs and is organized into five or possibly six exons that correspond to different domains of the alpha chain. The amino acid sequence deduced from the I-E alpha gene shows 75% homology to its human counterpart, the HLA-DR alpha chain. The absence of I-E antigen in H-2 mice is due to lack of E alpha chain synthesis. We show here that this defect is caused by a deletion in the 5' end of the I-E alpha b gene.

Identification of allergens in Dermatophagoides pteronyssinus mite body extract by crossed radioimmunoelectrophoresis with two different rabbit antibody pools

An extract of purified Dermatophagoides pteronyssinus mite bodies was investigated by crossed radioimmunoelectrophoresis (CRIE), using sera from 29 mite-allergic patients. Two CRIE series consisting of rabbit antibodies to (1) whole mite culture and to (2) purified mite bodies were run simultaneously, showing 27 and 29 precipitates, respectively. Cases of major discrepancy between the two series were ascribed to absence of antibody to allergenic components and to artefactual radiostaining due to inclusion of allergen in precipitates representing other antigens. Carefully performed controls were necessary to establish the reliability of CRIE. Specific response patterns in the studied set of sera were found to several of the represented antigens. Two major allergens appeared in both CRIE systems. Two intermediate and several minor allergens were further identified.

Amino-acid sequence of the beta 1 isosubunit of taipoxin, an extremely potent presynaptic neurotoxin from the Australian snake taipan (Oxyuranus s. scutellatus)

The amino acid sequence of the beta 1 isosubunit of taipoxin, an extremely potent presynaptic neurotoxin from the Australian snake taipan, has been determined. The beta 1 isosubunit, which is neither toxic nor enzymatically active on its own, consists of a single polypeptide chain of 118 amino acids. The main fragmentation of the reduced and S-carboxymethylated derivative was accomplished by cleavage with Staphylococcus aureus V8 protease. Tryptic peptides were used to align and complete the sequence, which was determined by automated Edman degradation. The taipoxin beta 1 isosubunit is closely homologous to the taipoxin alpha and gamma subunits and to enzymatically active pancreatic and elapid snake venom phospholipases A2.

The cell attachment domain of fibronectin. Determination of the primary structure

The complete amino acid sequence of the cell attachment domain of human plasma fibronectin (Pierschbacher, M. D., Hayman, E. G., and Ruoslahti, E. (1981) Cell 26, 259-267) has been determined by automated sequential degradation of a peptic fragment comprising this region and of peptides derived from this fragment by digestion with thermolysin, staphylococcal V8 protease, cyanogen bromide cleavage, and partial acid hydrolysis. The fragment contains 108 residues with isoleucine and methionine as the NH2- and carboxyl-terminal amino acids, respectively. No cysteines are present. The calculated molecular weight of the cell attachment fragment, based on the amino acid sequence, is 11,482, which is in good agreement with the molecular weight estimated by sodium dodecyl sulfate/polyacrylamide gel electrophoresis and ultracentrifugation. There are no homologies in this fragment with other published sequences. The implications of the structure of the cell attachment fragment to the molecular mechanism of cell-fibronectin interaction are discussed.

Amino-acid sequence of the alpha-subunit of taipoxin, an extremely potent presynaptic neurotoxin from the Australian snake taipan (Oxyuranus s. scutellatus)

The amino acid sequence of the alpha-subunit of taipoxin, an extremely potent presynaptic neurotoxin from the Australian snake taipan has been determined. The very basic protein, by itself a moderately neurotoxic phospholipase, consists of a single polypeptide chain of 119 amino acids. The main fragmentation of the reduced and S-carboxymethylated derivative was accomplished by cleavage with Staphylococcus aureus V8 protease and trypsin. Chymotryptic peptides and cyanogen bromide fragments were used to align and complete the sequence, which was determined by automated Edman degradation. The taipoxin alpha-subunit is closely homologous to the other taipoxin subunits and to other elapid snake venom phospholipases A2.

The faculty and continuing medical education: an attitude study

Meager or nonexistent faculty reward systems hamper continuing medical education (CME) programs conducted by U.S. medial schools. In light of a growing number of mandatory CME regulations and a consequent increase in physician attendance of CME programs, the need for a competent faculty is apparent. A survey of faculty members designed to ascertain the importance of a faculty reward system was conducted by the University of Washington Division of Continuing Medical Education. Results reveal that faculty members are twice as likely to teach in CME programs outside of the university system as within the system. Survey respondents of nonprofessor rand considered faculty advancement the single greatest source of encouragement to participate in CME programs, yet this participation is seldom considered by the university in evaluations for promotion or tenure. If medical schools are to accept a responsibility for the continuing education of medical professionals, a commitment to provide adequate faculty incentive is imperative.

complete amino-acid sequence of a non-neurotoxic, non-enzymatic phospholipase A2 homolog from the venom of the Australian tiger snake Notechis scutatus scutatus

The complete amino acid sequence of Notechis II-1, a non-neurotoxic, non-enzymatic phospholipase A2 homolog from the venom of the Australian tiger snake Notechis s. scutatus has been determined. The protein consists of a single chain of 119 amino acids. The main fragmentation of the reduced and S-carboxymethylated derivative was accomplished by cleavage with Staphylococcus aureus V8 protease. Tryptic peptides were used to align and complete the sequence, which was determined mainly by automated Edman degradation. Notechis II-1 contains all of the residues that appear to be invariant in elapid and pancreatic phospholipases A2 except at position 30 in the sesquence, where an otherwise invariant glycine is replaced by serine.

Detection and quantitation of Dermatophagoides antigens in house dust by immunochemical techniques

Rabbit antibodies against D. pteronyssinus whole culture extract were rendered specific to mite antigens by immunoabsorption with extract of human dander. Using the absorbed antibodies, an extract of a mite culture gave rise to 15 peaks in crossed immunoelectrophoresis and to a titer of 512 in counter-immunoelectrophoresis. When applied to dust samples from the homes of allergic patients, counterimmunoelectrophoresis gave reproducible results within an error of 1 titer-step. Mite antigens were detected in 64% of 105 dust samples investigated. The titer correlated well (P less than 0.005) with the concentration of Dermatophagoides bodies, found in 13 mattress dust samples by microscopy. Advantages and limitations of immunochemical quantitations of house dust mites in dust samples is discussed in relation to investigations by microscopy.