Stimulatory effect of pervanadate on calcium signals and histamine secretion of RBL-2H3 cells

We examined the effect of pervanadate on the activation of rat basophilic leukaemia (RBL-2H3) cells. The pervanadate, generated from a combination of H2O2 and vanadate (Vi), induced concomitantly protein tyrosine phosphorylation, formation of inositol 1,4,5-trisphosphate (IP3), an increase in [Ca2+]i, and histamine secretion in RBL-2H3 cells. These effects were clearly dependent on the ratio of H2O2/Vi. The secretion of histamine, IP3 formation, and sustained increase in [Ca2+]i were effectively induced by treatment of the cells with the pervanadate produced from 1 mM H2O2 and 1 mM Vi. These effects mimic the stimulatory effects of an antigen (dinitrophenylated BSA) on Ca2+ signals, histamine secretion and morphological changes. Protein tyrosine phosphorylation, formation of IP3 and transient increase in [Ca2+]i were markedly induced by the pervanadate produced from 3 mM H2O2 and 1 mM Vi. However, histamine secretion induced by the pervanadate was very low. After the pervanadate from 3 mM H2O2 and 1 mM Vi was treated with catalase, it was able to induce the [Ca2+]i increase and histamine secretion as much as the antigen did. This indicates that pervanadate from a lower H2O2 concentration (1 mM H2O2/1 mM Vi) and catalase-treated pervanadate from a higher H2O2 concentration (3 mM H2O2/1 mM Vi) are able to mimic the activity that was caused by cross-linking of IgE receptors with antigen. The present results also demonstrate that protein tyrosine phosphorylation seems to have a crucial role in Ca2+ entry from the external medium, and that a sustained [Ca2+]i increase is an important step for histamine secretion in RBL-2H3 cells.

Purification and characterization of dimeric dihydrodiol dehydrogenase from dog liver

High NADP(+)-linked dihydrodiol dehydrogenase activity was detected in dog liver cytosol, from which a dimeric enzyme composed of M(r) 39,000 subunits was purified to homogeneity. The enzyme oxidized trans-cyclohexanediol, and trans-dihydrodiols of benzene and naphthalene, the [1R,2R]-isomers of which were selectively oxidized. In the reverse reaction in the presence of NADPH as a coenzyme, the enzyme reduced alpha-dicarbonyl compounds, such as methylglyoxal, 3-deoxyglucosone, and diacetyl, and some compounds with a carbonyl group, such as glyceraldehyde, lactaldehyde, and acetoin. 4-Hydroxyphenylketones and ascorbates inhibited the enzyme. The results of steady-state kinetic analyses indicated that the reaction proceeds through an ordered bi bi mechanism with the coenzyme binding to the free enzyme, and suggested that the inhibitors bind to the enzyme-NADP+ binary complex. The dimeric enzyme was detected in liver and kidney of dog, and was immunochemically similar to the dimeric enzymes from monkey kidney, rabbit lens, and pig liver. The sequences (total 127 amino acid residues) of eight peptides derived on enzymatic digestion of the dog liver enzyme did not show significant similarity with the primary structures of members of the aldo-keto reductase and short chain dehydrogenase superfamilies, which include monomeric dihydrodiol dehydrogenases and carbonyl reductase, respectively.

Concentrations of alpha-tocopherol and its quinone derivative in cerebrospinal fluid from patients with vascular dementia of the Binswanger type and Alzheimer type dementia

We determined the concentrations of alpha-tocopherol (alpha-TOH) and alpha-tocopherol quinone(alpha-TQ), an oxidized derivative of alpha-TOH, in cerebrospinal fluid from patients with Alzheimer type dementia (ATD) and those with vascular dementia of the Binswanger type (VDBT). Compared with results for the controls, the VDBT patients had unaltered concentrations of alpha-TOH, but a statistically significant, 3.6-fold increase of alpha-TQ (P < 0.01) which was significantly correlated with decreases in the Mini-Mental State Examination scores (P < 0.05). In contrast, ATD patients had significantly decreased concentrations of alpha-TOH (P < 0.01), but had unaltered concentrations of alpha-TQ. These results suggest that there is greater oxidation of alpha-TOH to alpha-TQ in VDBT brain, but are inconclusive about the occurrence of peroxidation in ATD brains.

Association of thrombosis-inducing activity (TIA) with fatal hypercoagulable complications in patients with lung cancer

We previously reported that thrombosis-inducing activity (TIA) is present in plasma from patients with advanced lung cancer. Of 73 patients with non-small cell lung cancer, stages IIIb and IV, 41 (56 percent) had such activity in plasma. The median survival time was significantly shorter in the TIA-positive vs the TIA-negative group. When 34 of those 73 patients who had died at Kyushu University Hospital were evaluated for the incidence of disseminated intravascular coagulation (DIC) and adult respiratory distress syndrome (ARDS), they were significantly higher in the TIA positive group (p < 0.05). The DIC occurred in 7 of 20 patients positive for TIA and 5 died of ARDS. In contrast, in the 14 TIA-negative subjects, only 1 patients experienced DIC and none died of ARDS. Peripheral platelet counts, which had been rather elevated on the day of hospital admission, were below normal within 1 week of death in 40 percent of the 20 patients who were positive for TIA. These observations suggest that TIA may be responsible at least in part for the increased activity of the coagulation system and the high incidence of DIC and ARDS in patients with advanced lung cancer.

Deregulated expression of c-fos disturbs proliferative responses of B cells to sIg cross-linking

B cell activation by surface immunoglobulin (sIg) cross-linking is accompanied by transient expression of the c-fos protooncogene. This expression is strictly controlled in the B cells. To investigate a biological implication of the c-fos expression in the process of B cell activation by sIg cross-linking, we examined the proliferation of splenic B cells from H2-c-fos transgenic mice. Constitutive expression of the c-fos gene perturbs de novo synthesis of RNA and DNA in the B cells stimulated with anti-IgM antibody. Early events of signal transduction such as an increase in intracellular free calcium level and an induction of the endogenous immediate early genes (c-fos and c-myc) were apparently intact in those B cells. When the sIg stimulation of B cells was mimicked by the costimulation with 12-O-tetradecanoylphorbol 13-acetate and ionomycin, H2-c-fos B cells required higher concentrations of ionomycin for the optimal proliferative responses, suggesting that calcium-dependent signal transduction pathways are disturbed in those B cells. These results demonstrate a novel regulatory effect of c-fos protein on the proliferation of B cells mediated by sIg cross-linking.

Extracellular ATP regulates the proliferation of alveolar macrophages

We examined the effects of extracellular ATP on the proliferation and synthesis of DNA by guinea pig alveolar macrophages (AM). AM proliferated spontaneously in vitro, their number doubling in 72 h. Such proliferation was completely inhibited by adding 1 mM ATP to the culture. The inhibition was dose dependent. ATP also suppressed the spontaneous synthesis of DNA by AM. The inhibitory effect of ATP was not related to cell damage, as the viability and the superoxide anion-generating activity of these cells were unaffected by treatment with ATP for 24 h. The order of potency of the adenosine nucleotides (ATP > ADP > AMP) reflected the character of the P2 purinoceptor. Theophylline inhibited the effect of ATP on the synthesis of DNA by AM to a level produced by the nonhydrolyzable analogue, ATP gamma S, but did not influence the effect of ATP gamma S. These data suggest that the effect of ATP on the synthesis of DNA was exerted mainly via the P2 purinoceptor (82.0%) and to a lesser extent via the P1 purinoceptor (12.6%). We found that small molecules in the lavage fluid inhibited the synthesis of DNA by AM. Thus, the extracellular ATP present in the alveolar lining fluid may participate in controlling the proliferation of AM.

[Analysis of Fas antigen gene expression in human thymocytes fractionated with discontinuous gradients using bovine serum albumin]

Premature thymocytes proliferate and differentiate from immature to mature T lymphocytes through out both positive and negative selections in thymus. The clonal deletion is a major mechanism of cell selection and mainly depends on apoptosis. Recently, Itoh et al. isolated cDNAs encoding Fas antigen which mediate apoptosis and is expressed on mouse thymocytes. Herein, I further attempted to examine the expression of Fas antigen gene in human thymocytes from thymus resected at cardiac operations. Human thymocytes were separated into 5 fractions with discontinuous gradient using bovine serum albumin (BSA). They consisted of fractions I (BSA concentrations: 10-14%), II (14-16%), III (16-18%), IV (18-20%), and V (20-24%). Human thymocytes in each fraction were characterized regarding the rearrangement of T cell receptor (TCR) genes and the expression of human Fas antigen gene. Human thymocytes were divided into three sub populations according to their stages of differentiation and maturation. First population, thymocytes contained in fraction I, expressed interleukin 2 receptor alpha-chain (IL-2R alpha) and proliferated without the presence of recombinant IL-2 (rIL-2). Second, thymocytes contained in fraction II and III, expressed IL-2R alpha but could not proliferate without the presence of rIL-2. Third, thymocytes contained in fraction IV and V, could not express IL-2R alpha nor proliferate under any conditions assayed, and occupied over 90% of total human thymocytes in number. The southern blot analysis of T cell receptor beta-chain gene constant region (C beta) showed that C beta were rearranged in most of all thymocytes except for small population contained in fraction I. The reverse transcription-polymerase chain reaction (RT-PCR) analysis of Fas antigen gene expression revealed that the thymocytes in fraction I expressed Fas antigen gene more than those in any other fractions and that the thymocytes in fraction V expressed no Fas antigen gene. These results suggested that Fas antigen plays a minor role in the clonal deletion of postnatal human thymocytes.

Status of soil-transmitted helminthic infection in Nepal

A retrospective evaluation of the status of soil-transmitted helminthic infection in Nepal during the period from 1985 to 1992 was conducted at the Parasitology Laboratory, Department of Pathology, TU Teaching Hospital in Kathmandu. An average of 6,537 faecal samples were examined each year for the presence of various types of intestinal parasites. The annual rate of positivity of these samples for soil-transmitted helminthiasis ranged from 18.0 to 36.6%. The annual incidence decreased every successive calendar year in both adults and children, irrespective of sex. Among the various types of helminths, the most common was Ascaris lumbricoides (roundworm), followed by hookworm. The incidence of A. lumbricoides remained constant throughout the study period, while that of other parasites markedly decreased each year.

Molecular cloning of two human liver 3 alpha-hydroxysteroid/dihydrodiol dehydrogenase isoenzymes that are identical with chlordecone reductase and bile-acid binder

Human liver contains two dihydrodiol dehydrogenases, DD2 and DD4, associated with 3 alpha-hydroxysteroid dehydrogenase activity. We have raised polyclonal antibodies that cross-reacted with the two enzymes and isolated two 1.2 kb cDNA clones (C9 and C11) for the two enzymes from a human liver cDNA library using the antibodies. The clones of C9 and C11 contained coding sequences corresponding to 306 and 321 amino acid residues respectively, but lacked 5'-coding regions around the initiation codon. Sequence analyses of several peptides obtained by enzymic and chemical cleavages of the two purified enzymes verified that the C9 and C11 clones encoded DD2 and DD4 respectively, and further indicated that the sequence of DD2 had at least additional 16 residues upward from the N-terminal sequence deduced from the cDNA. There was 82% amino acid sequence identity between the two enzymes, indicating that the enzymes are genetic isoenzymes. A computer-based comparison of the cDNAs of the isoenzymes with the DNA sequence database revealed that the nucleotide and amino acid sequences of DD2 and DD4 are virtually identical with those of human bile-acid binder and human chlordecone reductase cDNAs respectively.

Ultrastructural localization of carbonyl reductase in mouse lung

The immunocytochemical localization of tetrameric carbonyl reductase in the mouse lung was determined by an electron-microscopical immunogold procedure using monospecific antibodies against the enzyme. The labelling of carbonyl reductase was observed within the mitochondria of the ciliated and non-ciliated cells of the bronchioles and the type II alveolar pneumocytes, and the density of labelling in the non-ciliated cells was higher than those in the other cells. No significant labelling was detected over other compartments of the epithelial cells. The labelling was undetectable in the type I alveolar cells, alveolar macrophages and connective tissue cells of the lung. These results clearly indicate the localization of carbonyl reductase to the mitochondrial matrix of these epithelial cells, of which the non-ciliated bronchiolar cells contained particularly high amounts of the enzyme.

Purification and reconstitution of an intestinal Na(+)-dependent neutral L-alpha-amino acid transporter

Using an improved reconstitution method, we have purified an Na(+)-dependent neutral L-alpha-amino acid transporter from rabbit small intestine to apparent homogeneity. The preparation solubilized with octaethylene glycol dodecyl ether (C12E8) was purified by successive chromatographies on DEAE-Toyopearl and lentil lectin-Sepharose 4B columns. The transport activity was assayed by reconstitution of the protein into liposomes. The specific activity of the final preparation was 1364-fold that of brush border membrane vesicles. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the active fractions gave one band of 90 kDa. Kinetic analysis using proteoliposomes reconstituted with the purified fraction showed that alanine transport was mediated by high affinity system with Kt value of 0.19 mM and Jmax value of 2.8 nmol/mg protein/s. Analysis of the amino acid composition of the purified transporter revealed that the transporter is very hydrophobic protein. From its specific activities for transport of individual amino acids this transporter was concluded to possess broad specificity for neutral L-alpha-amino acids. Furthermore, inhibition study of other amino acids allowed us to identify this transport pathway as the intestinal system B.

Effects of herbimycin A and ST638 on Fc epsilon receptor-mediated histamine release and Ca2+ signals in rat basophilic leukemia (RBL-2H3) cells

We examined the effect of the two protein tyrosine kinase inhibitors, alpha-cyano-3-ethoxy-4-hydroxy-5-phenylthiomethylcinnamide (ST638) and herbimycin A, on the activation processes of rat basophilic leukemia (RBL-2H3) cells by cross-linking of IgE receptors. RBL-2H3 cells sensitized with DNP-specific monoclonal IgE antibody were stimulated with multivalent antigen (DNP conjugate of bovine serum albumin). Analysis of phosphotyrosine-containing proteins in their lysates by SDS-PAGE and immunoblotting revealed that these two inhibitors efficiently inhibited the tyrosine phosphorylation of several proteins (32, 42, 56, 66, 72, 92, 150 kDa) including phospholipase C-gamma 1. The inhibitors also caused parallel inhibitions of the histamine release, the formation of inositol 1,4,5-trisphosphate, and the increase in cytosolic calcium ion concentration at the late sustained phase. A digital imaging fluorescence microscopic analysis of antigen-dependent calcium signals in individual cells showed that these two tyrosine kinase inhibitors inhibited the calcium influx from the external medium more powerfully than the mobilization of calcium ion from internal stores. In contrast, the inhibitors did not affect the increase in the cytosolic calcium ion concentration or the histamine release induced by the calcium ionophore A23187. Taken together, our results suggest that tyrosine phosphorylation following antigen stimulation regulates phosphatidylinositol hydrolysis and the influx of extracellular calcium.

Regional differences in glucose transport in the mouse hippocampus

In order to observe glucose transport into the brain, 6-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-6-deoxyglucose (NBDG), a non-metabolizable and fluorescent glucose analogue, was injected intravenously into mice. After ascertaining that this glucose analogue is non-metabolizable in the brain, the NBDG contents in the blood and brain were measured quantitatively by spectrofluorimetry at 0, 0.5, 2, 5, 10 and 30 min after intravenous injection. The NBDG content in the blood decreased markedly with time, whereas in the brain it rapidly decreased, then gradually increased after 2 min. Glucose transport into the hippocampus was observed with a confocal laser scanning microscope. At 0.5 min, NBGD was seen to be highly concentrated on the vascular wall. Using the confocal mode, it was found that the fluorescence was unevenly distributed on the microvessel wall, suggesting local differences of glucose transport in the vascular wall. At 5 min, the fluoresent intensity of the vascular wall was markedly decreased, whereas relatively intense fluorescence was observed in the cerebral parenchyma of the stratum lacunosum-moleculare and stratum pyramidale of Ca3. At 10 min, a weak fluoresence was diffusely distributed in the hippocampus. As to the localization of NBDG in the brain, capillary endothelium (luminal and abluminal membrane), basement membrane, and the feet of the astrocytes are discussed.

[Three siblings of painful muscle cramps (generalized muscle cramp disease) with alopecia and endocrinological disorders]

Three siblings with generalized painful muscle cramps, generalized alopecia, and endocrinological abnormalities are presented. Their clinical features are very similar to those in sporadic cases reported as having generalized muscle cramp disease. Autosomal recessive inheritance was suggested in our patients. Abnormal laboratory tests include hypersecretion of insulin after glucose loading, elevated levels of luteinizing hormone (LH) and follicular stimulating hormone (FSH), and hypersecretion of LH in the LH-RH test. An elevation of IgG and IgG index in the cerebrospinal fluid (CSF) of two patients suggests IgG production in the CSF. Oral administration of 75 to 150 mg of dantrolene sodium decreased the frequency, intensity, and duration of cramps in all cases. Autoimmune mechanisms based upon hereditary abnormalities are suggested as a cause of their disease.

[Effect of exercise in water on maternal blood circulation]

To elucidate the effects of exercise in water on the maternal circulation, twenty normal pregnancies were examined under the following three conditions; 1) on the land at rest, 2) during water immersion and 3) after the exercise in water. Their gestational ages were from 25 to 37 weeks (31 +/- 4 weeks, mean +/- S.D., n = 20). We examined the blood pressure, the urine volume throughout the examination, CBC and the levels of vasopressin, plasma renin activity and human atrial natriuretic peptide (hANP). The blood volume calculated from the Hb and Ht were significantly (p < 0.001) increased during the water immersion (105.8 +/- 2.5%), even after the exercise (101.6 +/- 2.9%). Vasopressin was decreased during the water immersion and increased after the exercise, but plasma renin activity was decreased in these two conditions. The hANP concentration was significantly (p < 0.001) increased after the exercise in water and correlated with the urine volume (ml/hour) during the examination. These results show that the decline in blood pressure and the increase in the urine volume during the maternal swimming were caused by the decreased plasma renin activity and the increased hANP concentration resulted from the blood volume expansion during the exercise in water.

[Effects of liposome-entrapped E. coli endotoxin on lung pathophysiology in rats]

The effects of repeated intravenous injections of E. coli endotoxin (ETX)-containing liposomes (LP) on the development of emphysematous change in rats were examined. Male Wistar rats, weighting 150-200 g, were divided into 3 groups. Group 1; rats treated with phosphate buffered saline (PBS), Group 2; rats treated with liposome-entrapped PBS, Group 3; rats treated with liposome-entrapped ETX (10 mg/ml). In each group, 0.5 ml was injected intravenously once a week for 8 consecutive weeks. After 8 weeks, functional and morphometrical analyses of lungs were performed. Functional residual capacity (FRC), total lung capacity (TLC), and static compliance (Cst.) were measured using a pressure plethysmograph for small animals. Mean linear intercept (MLI) and internal surface area (ISA) were also determined. TLC did not differ among the 3 groups. In rats treated with liposome-entrapped ETX, Cst. corrected by body weight (Cst./body weight) was significantly increased compared with that in liposome-entrapped PBS-treated rats. Further more, MLI was larger than that of the other 2 groups and ISA was less than that of the liposome-entrapped PBS-treated rats. These results suggest that liposome-entrapped ETX induces emphysematous changes in rats.

Fibrinogen Mitaka II: a hereditary dysfibrinogen with defective thrombin binding caused by an A alpha Glu-11 to Gly substitution

A new type of A alpha Glu-11 to Gly substitution has been identified in a congenitally abnormal fibrinogen, fibrinogen Mitaka II, derived from a 14-year-old female suffering from easy bruising since childhood. Plasma of the patient and fibrinogen purified therefrom were found to clot slowly by thrombin but in a normal fashion by ancrod, a thrombin-like snake venom enzyme. The ancrod-clotted fibrin gels were normally solid and turbid, whereas the thrombin-clotted gels were initially fragile and transparent but became gradually normalized during further incubation. On reverse-phase high-performance liquid chromatography, there was an additional peptide group eluted distinctly later than the corresponding normal fibrinopeptide A in the clot-liquor of the patient's samples. Sequence analysis of these aberrant peptides and isolated A alpha chains of the patient's fibrinogen showed that Glu at position 11 of the abnormal A alpha chain had been replaced by Gly. Studies using 125I-labeled thrombin showed that the binding with thrombin was evidently reduced for her fibrinogen and the aberrant fibrinopeptide A as compared with that for the normal controls, indicating that A alpha Glu-11 may be critical for the fibrinogen-thrombin interaction. Indeed, A alpha Glu-11 of fibrinogen has recently been proposed to stabilize the local conformation, including the beta-turn, and to form a salt bridge between its side-chain carboxyl group and the guanidino group of Arg-173 of thrombin based on crystallographic analyses using analogs of fibrinopeptide A complexed with thrombin (Stubb et al, Eur J Biochem 206:187, 1992 and Martin et al, J Biol Chem 267:7911, 1992).

The induction of murine tumor infiltrating lymphocytes (TIL) by interleukin-2 or T cell growth factor

Mice were injected in the foot pad with either 5 x 10(5) syngeneic plasmacytoma (MOPC104E) or fibrosarcoma cells (Meth A). Lymph nodes containing tumor cells were harvested 14 days later and cultured. In the presence of recombinant interleukin-2 (r-IL-2) predominantly tumor cells proliferated. Culture with T cell growth factor (TCGF) resulted in the growth of lymphoid cells. Concanavalin A (Con A) had only a modest effect on elimination of tumor cells in the culture. Tumor-infiltrating lymphocytes (TIL) prepared from the lymph nodes showed specific tumor-neutralizing activity when grown in the presence of TCGF. In vitro examination revealed that Meth A cells could not be lysed by TIL, while TIL from MOPC tumors showed tumor specific activity. This study may explain negative results in human trials with TIL induced by IL-2 alone.

[Combination therapy with low dose adriamycin for advanced or recurrent breast cancer. Hokkaido Breast Cancer Treatment Study Group]

Comparative clinical trials among 3 regimens for patients with advanced or recurrent breast cancer were performed as a multi-institutional joint study. Arm-I of 3 regimens consisted of a 3-day consecutive administration of adriamycin (ADM) at 10 mg/body every 4 weeks, a daily oral administration of cyclophosphamide (CPA), 5-FU and tamoxifen (TAM) at 100 mg, 200 mg, and 20 mg, respectively, and a once-a-week intramuscular or subcutaneous injection of OK-432 (OK) gradually increased from the initial dose of 1 KE to the maintenance dose of 5 KE. Arm-II contained methotrexate (MTX) at 10 mg/body for 3 consecutive days every 4 weeks in place of ADM in Arm-I. Arm-III contained neither ADM nor MTX. Of 69 cases registered, 52 were eligible, leaving 6 non-eligible and 11 incomplete cases. The results of the overall evaluation of 48 complete cases other than 4, in which the tumor was not exactly measured, were as follows. Arm-I resulted in 2 CR and 3 PR out of 19 cases, the response rate being 23.6% (5/19). Arm-II resulted in 1 CR out of 15, the response rate being 6.7% (1/15). In Arm-III, no response cases were found. No significant difference was observed among three treatment groups (p = 0.055), but in Arm-I, the response rate was higher than in the other treatment groups, suggesting that there is a probability of useful combined use of ADM.

Intestinal brush-border transport of the oral cephalosporin antibiotic, cefdinir, mediated by dipeptide and monocarboxylic acid transport systems in rabbits

Intestinal absorption of the orally active cephalosporin, cefdinir, was investigated using brush-border membrane vesicles prepared from rabbit small intestine. The initial uptake of cefdinir was pH-dependent, with increased uptake at acidic pH, and was not influenced by either sodium gradient or membrane potential difference. Cefdinir uptake was saturable with an apparent Michaelis constant of 8.1 mM. Initial uptake of cefdinir was inhibited by dipeptides (glycyl-L-proline and glycylsarcosine), beta-lactam antibiotics (cephradine, cefixime and penicillin V), and monocarboxylic acids (acetic acid and L-lactic acid), whereas the uptake of cephradine and cefixime was not inhibited by monocarboxylic acids. Cefdinir significantly inhibited the initial uptake of cephradine, cefixime and [3H]acetic acid. From these results, it was suggested that cefdinir was transported across brush-border membranes by both dipeptide and monocarboxylic acid carriers.

Use of the hemagglutinating virus of Japan (HVJ)-liposome method for analysis of infiltrating lymphocytes induced by hepatitis B virus gene expression in liver tissue

We previously developed a method for introducing foreign genes into liver tissue using liposomes with incorporated hemagglutinating virus of Japan (HVJ, Sendai virus), and found that liver cells transfected with the E. coli beta-galactosidase gene or the gene for hepatitis B virus (HBV) surface protein (HBsAg) expressed these proteins in vivo. Here, we analyzed cellular reactions leading to hepatitis in the liver by expressing the genes of HBV in vivo. Lymphocytes were eluted directly from liver transfected with the HBsAg genes and shown to be cytotoxic only to cells expressing HBsAg in vitro. These lymphocytes were identified as cytotoxic T lymphocytes with the CD4- CD8+ phenotype. Transfer of these lymphocytes to transgenic mice with the whole HBV genome led to elevation of the serum glutamic-pyruvic transaminase (SGPT) level, indicating the induction of hepatitis due to the cytotoxic T lymphocytes in vivo. Similarly, direct transfer of the gene for the HBV secretory core protein (HBeAg) induced expression of HBeAg in hepatocytes and the appearance of antibody against HBeAg in the serum. However, using this system, we found that the lymphocytes infiltrating the transfected liver showed no cytotoxicity specific for HBeAg. These results indicate that expression of HBsAg, one of the components of virions, in animal liver induced hepatitis efficiently through generation of specific cytotoxic T lymphocytes (CTL) without any expression of the other viral components. This in vivo experimental system should be useful for evaluating how expression of a given gene induces cellular reactions and intrinsic functions in the living body.

Temperature-sensitive phenotype of a mutant Sendai virus strain is caused by its insufficient accumulation of the M protein

We investigated the process interrupting the production of a temperature-sensitive mutant strain of Sendai virus, Cl.151, at the nonpermissive temperature (38 degrees C). The amount of virus M protein increased up to 6-fold when the cells persistently infected with Cl.151 strain at 38 degrees C are transferred to 32 degrees C, while the amount of nucleocapsid proteins did not alter. Cl.151 strain could restore virus production at 38 degrees C not only by the supplementation of M protein of wild type (Z) strain but also by the supplementation of M protein of Cl.151 strain. Neither the amount of M mRNA nor the rate of synthesis of M protein was altered by temperature in cells infected with the Cl.151 strain. However, we found that M protein of Cl.151 virus, which has 3-amino acid alterations from the wild type, was highly unstable at 38 degrees C when expressed under the control of an actin promoter. These results clearly show that Sendai virus M protein has a critical role in the production of virus particles without affecting virus gene expression.