Establishment of CHO cell lines expressing four N-methyl-D-aspartate receptor subtypes and characterization of a novel antagonist PPDC

To develop an assay system that allows the N-methyl-D-aspartate (NMDA) receptor subtype-selective antagonistic potency of drugs, we have established Chinese hamster ovary cell lines expressing the four NMDA receptor subtypes (GluRepsilon1/zeta1-GluRepsilon4/zeta1) heat-indelibly. Using these clonal cells, we found that a novel antagonist, (1S,2R)-1-phenyl-2[(S)-1-aminopropyl]-N,N-diethylcyclopropanecarboxamide, was less selective for the GluRepsilon1/zeta1: the IC(50) values for the GluRepsilon1/zeta1-GluRepsilon4/zeta1 were 41.7, 13.3, 12.6 and 11.5 microM, respectively, while two well-known antagonists, DL-2-amino-5-phosphonovaleric acid and ifenprodil, showed the known potency and selectivity for each subtype. Thus, the established clonal cells are of use in characterizing the pharmacological properties of drugs that act on NMDA receptors.

Primary antiphospholipid syndrome presenting with cerebral ischemia, thrombocytopenia, anemia and proteinuria successfully treated with warfarin potassium

A 30-year-old woman with primary antiphospholipid syndrome (PAPS) presented with cerebral ischemia, thrombocytopenia, anemia and proteinuria. Administration of warfarin potassium, without concomitant corticosteroid administration, significantly improved all of these symptoms along with a decrease in the titers of antiCL-beta2-GP-I antibodies and a shortening of prolonged APTT. Therefore, the antiphospholipid antibodies in this patient could have been evoked by vitamin-K-dependent coagulation factors or plasma proteins which are assumed to undergo conformational changes exposing cryptic epitopes. This case report provides clues to the mechanisms underlying the production of antiphospholipid antibodies in patients with PAPS.

Clinico-laboratory characteristics of patients with dermatomyositis accompanied by rapidly progressive interstitial lung disease

The clinico-laboratory features of 16 patients with dermatomyositis (DM) were compared between patients with accompanying rapidly progressive interstitial lung disease (RP-ILD, n = 7) and those with chronic interstitial lung disease (C-ILD, n = 9), and also between deceased (seven RP-ILD and three C-ILD) and living patients (six C-ILD). The extent of muscle weakness of the extremities and frequency of autoantibody positivity were significantly lower in DM patients with RP-ILD than in DM patients with C-ILD. Furthermore, significantly lower serum creatine kinase/lactate dehydrogenase levels (0.26+/-0.27) were found in the 10 patients who died than in the six living patients (1.21+/-1.09). A higher CD4+/CD8+ T-lymphocyte ratio in the peripheral blood (3.51+/-2.65) was detected in the four DM patients with RP-ILD who died than in the six living DM patients with C-ILD (1.22+/-0.49).

Two patients with polymyositis or dermatomyositis complicated with massive pleural effusion

Two patients with polymyositis (PM) or dermatomyositis (DM) complicated with massive pleural effusion are reported here. Both patients presented a high-grade fever, pleural effusion prominent on the right, and good response to steroid therapy. In a 50-year-old woman with PM, combined process of pleural inflammation, cardiomyopathy and coexisting hypothyroidism were considered to be responsible for the accumulation of the massive pleural effusion. However, in a 34-year-old man with DM, pleural inflammation associated with interstitial pneumonia or pleural microvasculopathy in DM was considered to be responsible for the accumulation of the massive pleural effusion.

Identification of lysine-238 of Escherichia coli biotin carboxylase as an ATP-binding residue

Escherichia coli biotin carboxylase was affinity labeled with adenosine diphosphopyridoxal to identify its ATP binding site. Lysyl endopeptidase digestion of the modified protein, followed by high performance liquid chromatography separation and amino acid sequencing allowed to identify lysine-238 to be the site of modification. Site-directed mutagenesis of this residue into alanine, arginine or glutamine resulted in mutants with much decreased activity. Lysine-238 seems to interact with the gamma-phosphate group of ATP but is not involved in catalysis.

Evidence for structural differences between the two highly homologous actin-regulatory proteins, destrin and cofilin

The amino acid sequences of destrin and cofilin are very similar (84% homology) throughout the entire range of proteins, but they have different functions. In this study, we constructed a new cofilin expression plasmid, which had high expression frequency, and the structures of destrin and cofilin were analyzed by limited proteolysis and circular dichroism (CD). When destrin was digested by trypsin, two fragments of 17.0 kDa and 9.2 kDa were obtained, whereas only one 8.4 kDa fragment was obtained from cofilin. In spite of the overall sequence homology, an N-terminal amino acid sequence analyses of the fragments revealed the cleavage sites on destrin and cofilin to be different. These results suggest that destrin and cofilin differ in their overall tertiary folds. Cofilin showed activity similar to destrin at high pH values, although no pH-dependent structural change in cofilin was confirmed by using limited proteolysis and CD.

Cloning and nucleotide sequence of Bacillus stearothermophilus pyruvate carboxylase

A gene for prokaryotic pyruvate carboxylase (PC) was cloned from Bacillus stearothermophilus. It has an open reading frame of 3441 base pairs which can code for a protein of 128,353 Da. Not only the molecular size and domain organization but also the deduced amino acid sequence of B. stearothermophilus PC are similar to those of eukaryotic PCs.

Enzymatic diagnosis of holocarboxylase synthetase deficiency using apo-carboxyl carrier protein as a substrate

We developed a simple and sensitive method for assessing holocarboxylase synthetase (HCS) activity that is based on measuring incorporation of [3H]biotin into apo-carboxyl carrier protein, a subunit of acetyl-CoA carboxylase from E. coli. Kinetic analysis of HCS from normal fibroblasts showed that the Km for biotin was 260 +/- 94 nmol/l (mean +/- S.D.; n = 5). In contrast, the Km values of HCS from two cell lines derived from patients with HCS deficiency were 7200 and 3700, clearly distinguishable from the control value. The sensitivity of this assay was so high that we were able to characterize a mutant enzyme whose activity had not been previously detected. Our method is useful for enzymatic diagnosis of HCS deficiency and characterization of HCS.

Idiopathic thrombocytopenic purpura complicated by intracranial hemorrhage in a 78-year-old male

A 78-year-old male was admitted to our hospital with cutaneous hemorrhage, aphasia and somnolence. On physical examination, he appeared drowsy and complained of epistaxis and multiple purpura. His platelet count was 8,000/microliters with a high level of PA-IgG, but the coagulation time was normal. A CT scan of the head revealed a left temporal and right frontal hemorrhage. Bone marrow aspiration revealed abundant megakaryocytes. He was diagnosed as having idiopathic thrombocytopenic purpura with intracranial hemorrhage. He was treated with prednisolone and azathioprine in addition to platelet infusions and high doses of gamma-globulin. After two months of treatment, the platelet count had risen to 40,000/microliters and his symptoms had subsided.

A case of autoimmune hemolytic anemia induced by IFN-beta therapy for type-C chronic hepatitis

A 51-year old woman who had type-C chronic hepatitis developed autoimmune hemolytic anemia after 4 weeks treatment with a total 48 million interferon-beta, 6 million 8 times. Indirect Coomb's test turned from negative to positive through IFN therapy and a complication of asymptomatic primary biliary cirrhosis was confirmed by histologic findings of the biopsied liver which was performed during IFN therapy and a presence of anti-mitochondrial antibody. After stopping IFN therapy and adding prednisolone anemia improved in getting negative indirect Coombs test but remaining positive direct Coombs test.

Overproduction and characterization of recombinant UDP-glucose pyrophosphorylase from Escherichia coli K-12

Using oligonucleotide probes synthesized on the basis of partial amino acid sequences, we have cloned and sequenced the gene of Escherichia coli K-12 encoding UDP-glucose pyrophosphorylase. The gene consists of 906 base pairs and encodes a polypeptide of 302 amino acid residues with a calculated molecular weight of 32,941. Its nucleotide sequence was found to be identical with that recently registered (EMBL, X59940) for a gene coding for an unknown 33-kDa protein, which was later annotated as UDP-glucose pyrophosphorylase on the basis of genetic studies. The UDP-glucose pyrophosphorylase gene, mapped at 27.3 min in the E. coli chromosome, complemented the galU mutation, which renders the bacterium unable to ferment galactose. The recombinant enzyme overproduced in E. coli cells and purified to homogeneity catalyzed the synthesis and pyrophosphorolysis of UDP-glucose by a sequential mechanism. The enzyme required Mg2+ for maximal activity and was inhibited by free UTP and pyrophosphate. The E. coli enzyme shows significant sequence similarities with the enzymes from Acetobacter xylinum and Salmonella typhimurium. However, little or no similarity was found with the eukaryotic enzymes that are involved in the biosynthesis of storage carbohydrates, or with other enzymes acting on similar sugar nucleotides. Thus, UDP-glucose pyrophosphorylases participating in diverse metabolic pathways can be classified structurally into the prokaryotic and eukaryotic groups, even though they have almost identical catalytic properties.

Exploring the active site in UDP-glucose pyrophosphorylase by affinity labelling and site-directed mutagenesis

UDP-glucose pyrophosphorylase catalyses the reversible uridylyl transfer from UDP-glucose to MgPPi, forming glucose 1-phosphate and MgUTP. We have identified, by using uridine di- and tri-phosphopyridoxals, five lysyl residues located at or near the UDP-glucose-binding site. Another reactive analogue, pyridoxal diphosphoglucose, also modified the same set of lysyl residues. Based on the amounts of labels incorporated into each lysyl residue, we have provided a hypothetical model for possible locations of the five lysyl residues around the substrates bound to the enzyme. This model was consistent with the results of the mutagenesis studies. Lys367 is essential for the catalysis, whereas Lys263 may participate in the binding of PPi and/or glucose 1-phosphate in the binary complex. On the other hand, the results of affinity labelling with pyridoxal 5'-diphosphate suggest the role of Lys329 in the direct interaction with PPi in the enzyme-UDP-glucose complex.

Probing the pyrophosphate-binding site in potato tuber UDP-glucose pyrophosphorylase with pyridoxal diphosphate

Potato tuber UDP-glucose pyrophosphorylase (EC 2.7.7.9) catalyzes the reversible uridylyl transfer from UDP-glucose to MgPPi forming glucose 1-phosphate and MgUTP, according to an ordered bi-bi mechanism in which UDP-glucose and MgPPi bind in this order. To probe the active site of this enzyme, we have applied pyridoxal 5'-diphosphate, a reactive PPi analogue. The enzyme was rapidly inactivated when incubated with the reagent in the presence of Mg2+ followed by sodium borohydride reduction. The degree of the inactivation was decreased by MgUTP, MgPPi, and glucose 1-phosphate, but enhanced by UDP-glucose. The enhancement was prevented by co-addition of Pi, the competitive inhibitor with respect to PPi. The complete inactivation corresponded to the incorporation of 0.9-1.1 mol of reagent/mol of enzyme monomer. In the presence of UDP-glucose, labels were almost exclusively incorporated into Lys-329. Thus, this residue may be located near the bound MgPPi and its modification is promoted, probably through conformational changes, by the binding of UDP-glucose to the enzyme. The results of the modification by the same reagent of the mutant enzymes in which Lys-329 and Lys-263 are individually replaced by Gln suggest the roles of these lysyl residues in the binding of MgPPi and in the UDP-glucose-induced conformational changes, respectively.

Carbamazepine-induced systemic lupus erythematosus-like disease

A 14-year-old female developed systemic lupus erythematosus (SLE)-like symptoms, rash, fever, leukopenia and positive anti-nuclear antibody (ANA) two weeks after administration of carbamazepine (CBZ; Tegretol) used against benign Rolandic epilepsy. Clinical symptoms and leukopenia normalized after discontinuation of CBZ and administration of prednisolone at 40 mg. The cases of CBZ-induced SLE reported in the literature were reviewed.

Comparative affinity labeling with reactive UDP-glucose analogues: possible locations of five lysyl residues around the substrate bound to potato tuber UDP-glucose pyrophosphorylase

By using two reactive analogues of UDP-Glc, uridine di- and triphosphopyridoxals, we have recently probed the substrate-binding site in potato tuber UDP-Glc pyrophosphorylase [EC 2.7.7.9]. In this work, pyridoxal diphospho-alpha-D-glucose was used for the same purpose. This compound is also a reactive UDP-Glc analogue but having its reactive group on the opposite side of the pyrophosphate linkage to those of the above two compounds. The enzyme was rapidly inactivated when incubated with the compound at very low concentrations followed by reduction with sodium borohydride. The inactivation was almost completely prevented by UDP-Glc and UTP. Complete inactivation correspond to the incorporation of 1.0 mol of the reagent per mol of enzyme monomer. The label was found to be distributed in five lysyl residues (Lys-263, Lys-329, Lys-367, Lys-409, and Lys-40. All of these results were similar to those obtained previously with the other compounds, suggesting the presence of a cluster of five lysyl residues at or near the substrate-binding site of this enzyme. However, the incorporations of labels into each lysyl residue differed depending on the compounds used. The substrate retarded the incorporations in different manners. Based on the combined results of the present and previous studies, a hypothetical model is presented for the possible locations of the five lysyl residues around the substrate bound to the enzyme. This model is consistent with the kinetic properties of mutant enzymes in which the five lysyl residues were individually replaced by glutamine via site-directed mutagenesis.

Identification of lysyl residues located at the substrate-binding site in UDP-glucose pyrophosphorylase from potato tuber: affinity labeling with uridine di- and triphosphopyridoxals

Uridine di- and triphosphopyridoxals were used to probe the substrate-binding site in potato tuber UDP-glucose pyrophosphorylase (EC 2.7.7.9). The enzyme was rapidly inactivated in time- and dose-dependent manners when incubated with either reagent followed by reduction with sodium borohydride. The inactivations were almost completely retarded by UDP-Glc and UTP but only slightly by alpha-D-glucose 1-phosphate. The complete inactivation corresponded to the incorporation of about 0.9-1.0 mol of either reagent per mole of enzyme monomer. Both reagents appear to bind specifically to the UDP-Glc-(UTP)-binding site. Structural studies of the labeled enzymes revealed that the two reagents modified the identical set of five lysyl residues (Lys-263, Lys-329, Lys-367, Lys-409, and Lys-410), in which Lys-367 was most prominently modified. The ratios of the amounts of labels incorporated into these residues were similar for the two reagents. Furthermore, linear relationships were observed between the residual activities and the amounts of incorporation into each lysyl residue. We conclude that the five lysyl residues are located at or near the UDP-Glc(UTP)-binding site of potato tuber UDP-Glc pyrophosphorylase and that the modification of these residues occurs in a mutually exclusive manner, leading to the inactivation of the enzyme.

Expression in Escherichia coli of UDP-glucose pyrophosphorylase cDNA from potato tuber and functional assessment of the five lysyl residues located at the substrate-binding site

The entire structural gene for potato tuber UDP-glucose pyrophosphorylase has been amplified from its cDNA by the polymerase chain reaction and inserted into the expression plasmid pTV118-N downstream from the lac promoter. Escherichia coli JM105 cells carrying thus constructed plasmid produced the enzyme to a level of about 5% of the total soluble protein upon induction with isopropyl beta-D-thiogalactopyranoside. The recombinant enzyme purified to homogeneity in two column chromatographic steps was structurally and catalytically identical with the enzyme purified from potato tuber except for the absence of an N-terminal-blocking acetyl group. To examine functional roles of the five lysyl residues that had been identified by affinity labeling studies to be located at or near the active site of the enzyme [Kazuta, Y., Omura, Y., Tagaya, M., Nakano, K., & Fukui, T. (1991) Biochemistry (preceding paper in this issue)], they were replaced individually by glutamine via site-directed mutagenesis. The Lys-367----Gln mutant enzyme was almost completely inactive, and the Lys-263----Gln mutant enzyme had significantly decreased Vmax values with perturbed Km values for pyrophosphate and alpha-D-glucose 1-phosphate. Lys-329----Gln also exhibited increased Km values for these substrates but exhibited Vmax values similar to those of the wild-type enzyme. The two mutant enzymes Lys-409----Gln and Lys-410----Gln showed catalytic properties almost identical with those of the wild-type enzyme. Thus, among the five lysyl residues, Lys-367 is essential for catalytic activity of the enzyme and Lys-263 and Lys-329 may participate in binding of pyrophosphate and/or alpha-D-glucose 1-phosphate.

UDP-glucose pyrophosphorylase from potato tuber: cDNA cloning and sequencing

We have isolated a cDNA encoding UDP-glucose pyrophosphorylase from a cDNA library of immature potato tuber using oligonucleotide probes synthesized on the basis of partial amino acid sequences of the enzyme. The cDNA clone contained a 1,758-base-pair insert including the complete message for UDP-glucose pyrophosphorylase with 1,431 base pairs. The amino acid sequence of the enzyme inferred from the nucleotide sequence consists of 477 amino acid residues. All the partial amino acid sequences determined protein-chemically [Nakano et al. (1989) J. Biochem. 106, 528-532] confirmed the primary structure of the enzyme. An N-terminal-blocked peptide was isolated from the proteolytic digest of the enzyme protein, and the blocking group was deduced to be an acetyl group by fast atom bombardment-mass spectrometry. On the basis of the predicted amino acid sequence (477 residues minus the N-terminal Met plus an acetyl group), the molecular weight of the enzyme monomer is calculated to be 51,783, which agrees well with the value determined by polyacrylamide gel electrophoresis. In the cDNA structure, the open-reading frame is preceded by a 125-base-pair noncoding region, which contains a sequence being homologous with the consensus sequence for plant genes, and is followed by a 174-base-pair noncoding sequence including a polyadenylation signal. Amino acid sequence comparisons revealed that the potato UDP-glucose pyrophosphorylase is homologous to the enzyme from slime mold, Dictyostelium discoideum, but not to ADP-glucose pyrophosphorylases from rice seed and Escherichia coli.

A rapid microassay for dirofilarial antibodies by using antigen-coated nitrocellulose paper

This study describes an enzyme (horseradish peroxidase)-linked immunosorbent assay using nitrocellulose (NC) paper (Dot-ELISA) for the detection of antibodies against Dirofilaria immitis in dogs. Dirofilarial antigens prepared were directly bound on NC paper set into a microfiltration apparatus to ensure their uniformity. Of the 23 infected dogs tested, 21 were determined positive by visual observation of brown-colored spots on NC paper. The positive and negative readings were further confirmed by using a densitometer. Sera from 15 non-infected and 17 other parasite-infected dogs were all negative, i.e. no false positive readings and low cross-reactivities were found using this technique. Also, a large number of samples could be assayed simultaneously within 1.5 h. The Dot-ELISA technique reported here may be useful to veterinarians and also may be a means of field surveying human filariasis.

A rapid detection of toxocaral antibodies by dot enzyme-linked immunosorbent assay (dot-ELISA) in dogs

This study describes an enzyme-linked immunosorbent assay using antigen-coated nitrocellulose (NC) paper (Dot-ELISA) for detecting antibodies against Toxocara canis infection in dogs. Some advantages could be achieved by using a Dot-ELISA; 1) antigen could be directly and immediately bound on NC paper, 2) this assay could be carried out within 1.5 h, 3) all assay steps could be performed at room temperature, 4) the well-defined blue spots formed on NC paper could be evaluated by both visual observation and densitometric reading. The Dot-ELISA reported here may prove to be useful for the diagnosis of canine toxocariasis.

Detection of circulating immune complexes in the sera of dogs infected with Dirofilaria immitis, by Clq-binding enzyme-linked immunosorbent assay

The presence of circulating immune complexes (CIC) in the sera of dogs infected with Dirofilaria immitis was detected by using a Clq-binding enzyme-linked immunosorbent assay. Specificity of this assay with different concentrations of heat-aggravated canine IgG (ACG) was observed, i.e., the ELISA readings, expressed as microgram equivalents ACG/ml, increased with increasing amounts of ACG. The intra-assay variability was below 10%. The CIC levels of infected and uninfected dogs were 177.0 +/- 104.7 micrograms/ml and 22.8 +/- 45.8 micrograms/ml (mean +/- SD), respectively. The highest level was observed in 12 dogs with amicrofilaraemic infection. Age distribution of CIC levels in the 23 infected dogs also showed a significant positive correlation. These findings suggested that the CIC are present in the sera of dogs with dirofilariasis and may relate to canine glomerulonephritis.

The enzyme-linked immunosorbent assay for detecting antibodies against Dirofilaria immitis in dogs

Antisera prepared in mice by injection of antigens from Dirofilaria immitis, Toxocara canis, Dipylidium canium and Fasciola hepatica and sera from Dirofilaria-infected and non-infected dogs were tested at different dilutions using an enzyme-linked immunosorbent assay (ELISA). For this ELISA, adult D. immitis antigen was fractionated by gel filtration methods and then absorbed with immunoadsorbent-fixed IgG fractions from mouse sera immunized with various parasites. The results indicated satisfactory discrimination between antisera to D. immitis and those to other parasites. A significant ELISA O.D. value was considered to be greater than or equal to 0.30 with a 1 : 250 dilution of the dog sera. However, the lack of significant differences between the O.D. value of microfilaraemic and amicrofilaraemic infections was observed. These facts suggest that the use of immunoadsorbent chromatography for canine dirofilariasis is especially useful for purifying antigens and eliminating cross-reactions against other parasitic infections, when immunological methods are used for serodiagnosis.

Detection of circulating toxocaral antigens in dogs by sandwich enzyme-immunoassay

This study describes the presence of circulating toxocaral antigens (CTA) in the sera of dogs infected with Toxocara canis (T. canis) by using a sandwich enzyme-immunoassay (SEIA). A specificity of this assay with different antigens was observed, i.e. the EIA values, which express the antigen concentration, of excretory-secretory antigen from T. canis larvae were higher than those of other antigens (Ascaris lumbricoides, Dirofilaria immitis and Fasciola hepatica). The variability in intra-assay was below 10%. In age distribution of CTA levels, the highest level was observed at 1 month of age. Thereafter, the levels decreased gradually until 6 months of age and then the same levels were maintained until adult age. Also, slightly elevated levels were found in the sera of foetuses. A significant correlation was obtained between age and CTA levels. The positive correlation between the number of worms and CTA levels was significant. As for the IgG, IgM and IgA antibodies, a significant correlation was observed between the IgM antibody activities and CTA levels, but this was not observed with IgG and IgA antibodies. From these results, it was indicated that the immunological response to T. canis infection in dogs may not be reached until 1 or 2 months after birth, although detectable CTA levels were observed in foetal and early life. It was also suggested that the immunological stimulation for canine toxocariasis may be maintained by the excretory-secretory materials from the larvae through life and as a result, IgM antibody production may be observed even in chronically infected adult dogs. The SEIA technique reported in this study may be useful as a diagnostic tool of human toxocariasis, since the CTA can be directly demonstrated by the technique.

The IgA antibody activities in relation to the parasitologic status of Toxocara canis in dogs

In this study, the relationship between the IgA antibody activities to Toxocara canis infection in dogs and their parasitologic status has been examined. The enzyme-linked immunosorbent assay was applied to the sera of dogs for the detection of the specific IgA antibodies and at the same time, autopsy and stool examination were performed on these dogs. The most elevated IgA antibody levels were observed in the one-month age group of puppies. Thereafter, the levels gradually decreased until six and 10 months of age. These low levels were maintained in adult dogs. However, the IgA antibody activities were not related to the age and the number of worms when the correlation coefficients were calculated. It was suggested from the results obtained that the elevated IgA antibodies at one month of age may have been due to the locally stimulated immunity by the adult worms grown up in the intestines and as a result, could be detected in the circulation.

Preliminary study on the follow-up observations of the antibodies and circulating antigens in canine toxocariasis

In the sera of dog fetuses and newborn puppies, no antibody to Toxocara canis was found but an elevation of the circulating toxocaral antigens (CTA). In the mother dogs, detectable IgG and IgM antibodies were found. The IgG antibodies gradually increased in the course of this observation. The most elevated levels of IgA antibodies were observed one month after birth. The same was true for the CTA levels. There was no placental transfer of the antibodies nor could they be transferred from the mother dog to the offspring via the colostrum.

Detection of specific IgM antibodies to toxocaral ES antigen: effect of absorption of sera with protein A sepharose

The activity of both the IgG and IgM antibodies to ES antigen from Toxocara canis larvae was tested before and after absorption of sera by protein A Sepharose 4B (PASB). For this purpose, the ELISA technique was applied to the sera from 12 dogs and 6 infants. The effect of absorption of sera by PASB was as follows. The average values before and after absorption in dog sera were 0.11 and 0.02, respectively. The same effect was observed in the infant sera. Of the 12 dog sera tested, four had a elevated IgM activity and three were considered to be false positive. Also, two adult dogs in chronic infection had a IgM antibody. Of the six infant sera tested, one had a slightly elevated IgM activity and no false positive and negative readings were found. The results of this work indicated that the absorption of sera with protein A might be useful in detecting the IgM antibodies to ES antigen. Although the false positive readings appeared without absorption of sera, misreadings hampered by the amount of IgG be eliminated after absorption.

The IgM antibody activities in relation to the parasitologic status of Toxocara canis in dogs

In order to interpret the relation between the IgM antibody activities to Toxocara canis (T. canis) and the parasitologic status, sera from puppies and adult dogs were measured by the enzyme-linked immunosorbent assay. At the same time, autopsy was performed on these dogs for counting the number of T. canis worms and stool examination was carried out for observing the fertilization of eggs. The rates of infection by T. canis in the dogs decreased with age. The number of worms in the intestines ranged one to 39. The IgM antibody activities gradually increased until 3 months of age. Thereafter the significant levels were maintained even at the adult age. However, the IgM antibody levels were not associated with the age and the number of worms (P greater than 0.05) when the correlation coefficients were calculated between them. In contrast to the IgG antibodies, the results of the present study indicated that the IgM antibody activities do not relate to the age, the number of worms and the fertilization of eggs.

A relation between antibody response and acetylcholinesterase activity in dogs and rabbits infected with Toxocara canis

A relation between IgG antibodies and acetylcholinesterase (ACHE) activities was observed in the sera of dogs and rabbits infected with Toxocara canis (T. canis). No antibodies were found in the sera of dogs' fetuses and newborns, more over their ACHE levels were lower than the ones registered in the sera of adult dogs. The ACHE levels of both, the mother dog and the newborn puppies, reached the same level 3 months after delivery. Similar results were obtained in the sera of puppies and adult dogs. In the sera of two rabbits experimentally infected with T. canis, the IgG antibodies were sharply raised 2 weeks after infection and the ACHE levels gradually decreased during the course of this observation. The serum glutamic pyruvic transaminase further tested in these sera gradually increased. From the results obtained, the liver disfunction could be recognized in rabbits but not in dogs, and no relation between antibody and ACHE activities was found neither in the sera of dogs nor rabbits.