The control effect of histamine on body temperature and respiratory function in IgE-dependent systemic anaphylaxis

BACKGROUND

The systemic anaphylaxis reaction comprises various symptoms, including hypotension, changes in respiration pattern, and hypothermia.

OBJECTIVE

To elucidate the role of histamine in each of these symptoms, we induced the passive systemic anaphylaxis reaction in histidine decarboxylase gene knockout (HDC [-/-]) mice, which lack histamine.

METHODS

HDC(-/-) mice were generated by knocking out the HDC gene, which codes for the unique histamine-synthesizing enzyme. Twenty-four hours after the injection of IgE, HDC(+/+) and HDC(-/-) mice were injected with allergen and body temperature, blood pressure, and respiratory function were monitored in each mouse.

RESULTS

Blood pressure dropped in both the HDC(-/-) mice and the HDC(+/+) mice. In contrast, respiratory frequency dropped and the expiratory respiration time was elongated only in the HDC(+/+) mice. Body temperature was decreased in the HDC(+/+) mice and was practically unchanged in the HDC(-/-) mice. Histamine receptor antagonists blocked the body temperature drop in the HDC(+/+) mice. Intravenous histamine induced similar patterns of body temperature decrease in the HDC(+/+) mice and the HDC(-/-) mice. Mast cell-deficient W/W (v) mice did not show the decrease in body temperature; this suggests that the histamine that contributed to the decrease in body temperature was derived from mast cells.

CONCLUSION

According to the results of this investigation, in the passive systemic anaphylaxis reaction, respiratory frequency, expiratory time, and body temperature are shown to be controlled by the activity of histamine, but its contribution to blood pressure is negligible.

Impaired dendritic cell maturation and increased T(H)2 responses in PIR-B(-/-) mice

Mice deficient for paired immunoglobulin (Ig)-like receptor B (PIR-B) show defective regulation of receptor-mediated activation in antigen-presenting cells. Older PIR-B(-/-) mice had an increased number of peritoneal B1 cells. Splenic PIR-B(-/-) B2 cells were constitutively activated and proliferated much more than those from wild-type mice upon B cell receptor ligation. T helper type 2 (T(H)2)-prone humoral responses were augmented in PIR-B(-/-) mice upon immunization with T-dependent antigens, including increased interleukin 4 and decreased interferon-gamma responses, as well as enhanced IgG1 and IgE production. Impaired maturation of dendritic cells (DCs), possibly due to perturbed intracellular signaling, was responsible for the skewed responses. Thus, PIR-B is critical for B cell suppression, DC maturation and for balancing T(H)1 and T(H)2 immune responses.

The pre-B cell receptor signaling for apoptosis is negatively regulated by Fc gamma RIIB

Many studies have shown that FcgammaRIIB is a negative regulator of B cell receptor signaling, and even though FcgammaRIIB is expressed through all developmental stages of the B cell lineage, its involvement in pre-B cell receptor (pre-BCR) signaling has not been examined. To investigate FcgammaRIIB function at the pre-B cell stage, we have established pre-BCR positive pre-B cell lines from normal mice and FcgammaRIIB-deficient mice, named PreBR and Fcgamma(-/-)PreBR, respectively. These cell lines are able to differentiate into immature B cells in vitro by removal of IL-7. In PreBR, apoptosis was moderately induced by F(ab')(2) anti-mu Ab, but not by intact anti-mu Ab. Phosphorylation of SH2-containing inositol 5-phosphatase (SHIP) and Dok, which are involved in FcgammaRIIB signaling, was induced by anti-mu cross-linking in PreBR. In contrast, apoptosis was strongly induced by both the F(ab')(2) and intact anti-mu Abs in Fcgamma(-/-)PreBR, and the level of phosphorylation of SHIP or Dok was much lower in Fcgamma(-/-)PreBR than those observed in PreBR. Restoration of FcgammaRIIB to Fcgamma(-/-)PreBR followed by anti-mu cross-linking blocked severe apoptosis, and up-regulated SHIP and Dok phosphorylation. The results demonstrate that FcgammaRIIB negatively regulates pre-BCR-mediated signaling for apoptosis.

[The status of NIHS Information and Computing Infrastructure (NICI)]

From 1999 to 2000, NIHS Information and Computing Infrastructure (NICI) were newly renovated. The purposes of the renovation are (1) the improvement of the communication for business works in NIHS, (2) supporting for the research, (3) supporting for the administration work. The Internet connection speed was upgraded from 256 Kbps to 1.5 Mbps. The high quality network sever machines and database server machines were installed. The large-scale software systems were renewed their versions. Four experimental stations for medical plants at Hokkaido, Izu, Wakayama and Tanegashima connected to NIHS at Tokyo or Osaka branch by ISDN. We describe the providing information on NIHS home page, and how to utilize NICI for our research and official works.

[Development of research support environment for molecular pharmacology and toxicology]

The Chem-Bio Informatics division has developed the institute-wide computer network which is connected to the Internet via IMnet (Inter Ministry Network) sponsored by the Government. We call the network and associated information and computing infrastructure as NICI, the NIHS Information and Computing Infrastructure. The primary goal of NICI is to provide general communication environment such as e-mails, and the second goal is to provide WWW environment. Accomplishing these two goals the division is now challenging to develop information and computing environment that directly supports pharmaceutical and toxicological research. The prototype of this environment which consists of various chemical and biomolecular databases and computing tools has been developed under the name of MOBI-DICS. The concept and vision on how to extend the prototype to institute-wide infrastructure was discussed.

[Development of domain specific search engines]

As cyber space exploding in a pace that nobody has ever imagined, it becomes very important to search cyber space efficiently and effectively. One solution to this problem is search engines. Already a lot of commercial search engines have been put on the market. However these search engines respond with such cumbersome results that domain specific experts can not tolerate. Using a dedicate hardware and a commercial software called OpenText, we have tried to develop several domain specific search engines. These engines are for our institute's Web contents, drugs, chemical safety, endocrine disruptors, and emergent response for chemical hazard. These engines have been on our Web site for testing.

Drastic up-regulation of Fcepsilonri on mast cells is induced by IgE binding through stabilization and accumulation of Fcepsilonri on the cell surface

It has been shown that IgE binding to FcepsilonRI on mast cells results in increased FcepsilonRI expression, which in turn enhances IgE-dependent chemical mediator release from mast cells. Therefore, prevention of the IgE-mediated FcepsilonRI up-regulation would be a promising strategy for management of allergic disorders. However, the mechanism of IgE-mediated FcepsilonRI up-regulation has not been fully elucidated. In this study, we analyzed kinetics of FcepsilonRI on peritoneal mast cells and bone marrow-derived mast cells. In the presence of brefeldin A, which prevented transport of new FcepsilonRI molecules to the cell surface, levels of IgE-free FcepsilonRI on mast cells decreased drastically during culture, whereas those of IgE-bound FcepsilonRI were stable. In contrast, levels of FcgammaRIII on the same cells were stable even in the absence of its ligand, indicating that FcepsilonRI alpha-chain, but not beta- and gamma-chains, was responsible for the instability of IgE-free FcepsilonRI. As far as we analyzed, there was no evidence to support the idea that IgE binding to FcepsilonRI facilitated synthesis and/or transport of FcepsilonRI to the cell surface. Therefore, the stabilization and accumulation of FcepsilonRI on the cell surface through IgE binding appears to be the major mechanism of IgE-mediated FcepsilonRI up-regulation.

Effects of double mutation at two distant IgE-binding sites in the three-dimensional structure of the major house dust mite allergen Der f 2 on IgE-binding and histamine-releasing activity

Recently, we reported that introduction of mutations that induced conformational changes of the major mite allergen Der f 2 was an efficient strategy to reduce the allergenicity for safer allergen-specific immunotherapy. In this study, we evaluated another strategy, disruption of two independent IgE epitopes without inducing conformational change. We analyzed allergenicities of the wild-type Der f 2, two single mutants with a mutation at either of the two IgE-binding sites (K15A and K77A), and a double mutant with mutations at both of the sites (K15/77A). Purified recombinant forms of Der f 2 expressed in Escherichia coli had correct disulfide bonds, equivalent apparent molecular masses of approximately 15 kDa, and similar secondary structures. The mutants of Der f 2 had less IgE reactivities than the wild-type Der f 2 and reduced inhibitory activities for IgE-binding to the wild-type Der f 2. However, the mutations did not significantly reduce histamine-releasing activity.

A case of AFP-producing early gastric carcinoma with rapid growth liver metastasis

An 84-year-old man presented with complaints of epigastric discomfort. Upper gastrointestinal series and endoscopy showed an elevated lesion at the posterior wall of greater curvature on the gastric fundus. Diagnosed as moderately differentiated tubular adenocarcinoma by biopsy, wedge resection and 4sa regional lymph node dissection were carried out. The tumor morphology showed type I with slight elevation, 2.5 x 1.7 cm in size; histological showed papillary, tubular, and solid formations having clear cytoplasm and large bizarre nuclei invading the deep submucosal layer (sm2). This case was evaluated as T1(sm) N0 M0 stage Ia early gastric cancer. In the 5th month after operation, multiple liver metastases were detected. He died of liver failure by rapid growth of metastatic tumors in the 6th month after operation. The serum alpha-fetoprotein level at recurrence was 1,900 ng/mL, and alpha-fetoprotein-positive cells were immunohistochemically detected in operative and liver biopsy specimens.

Activating and inhibitory nature of the murine paired immunoglobulin-like receptor family

Clones for murine paired immunoglobulin-like receptors (PIR) were first isolated as those coding for type I transmembrane glycoproteins with six immunoglobulin-like domains homologous to human Fc alphaR, bovine Fc gamma2R, and other related receptors. However, they turned out to bind neither IgA nor other immunoglobulins in the case of the ectopic expression on COS-1 fibroblastic cells. PIR-A and B are expressed on a wide variety of cells in the murine immune system, such as in B cells, mast cells, macrophages, and dendritic cells, mostly in a pairwise fashion. PIR-A requires homodimeric Fc receptor common gamma chain, which harbors an immunoreceptor tyrosine-based activation motif, for its efficient cell surface expression and for the delivery of activation signaling. In contrast, PIR-B contains immunoreceptor tyrosine-based inhibitory motifs (ITIMs) in its cytoplasmic portion and inhibits receptor-mediated activation signaling in vitro upon engagement with other activating-type receptors such as the antigen receptor on B cells and the high affinity Fc receptor for IgE on mast cells. ITIMs of PIR-B on macrophages and B cells have been shown to be constitutively phosphorylated in their tyrosine residues. Although the ligand for PIR still remains unknown, the transgenics and the gene-targeted mice will provide us with valuable information on their physiological roles in the immune regulation.

A critical role of Fc receptor-mediated antibody-dependent phagocytosis in the host resistance to blood-stage Plasmodium berghei XAT infection

Plasmodium berghei XAT is an irradiation-induced attenuated variant derived from the lethal strain P. berghei NK65, and its blood-stage parasites are spontaneously cleared in immune competent mice. In the present study, we studied the mechanism of host resistance to blood-stage malaria infection using P. berghei XAT. Infection enhanced Ab-dependent phagocytosis of PRBC by splenic macrophages in wild-type C57BL/6 mice. In contrast, FcR gamma-chain knockout (FcRgamma(-/-)) mice, which lack the ability to mediate Ab-dependent phagocytosis and Ab-dependent cell-mediated cytotoxicity through FcgammaRI, FcgammaRII, and FcgammaRIII, could not induce Ab-dependent phagocytic activity. These FcRgamma(-/-) mice showed increased susceptibility to the P. berghei XAT infection, with eventually fatal results, although they produced comparable amounts of IFN-gamma by spleen cells and anti-XAT Abs in serum. In addition, passive transfer of anti-XAT IgG obtained from wild-type mice that had recovered from infection into FcRgamma(-/-) mice could not suppress the increase in parasitemia, and almost all of these mice died after marked parasitemia. In contrast, passive transfer of anti-XAT IgG into control wild-type mice inhibited the increase in parasitemia. IFN-gamma(-/-) mice, which were highly susceptible to the P. berghei XAT infection, failed to induce Ab-dependent phagocytic activity and also showed reduced production of serum anti-XAT IgG2a isotype compared with control wild-type mice. These results suggest that FcR-mediated Ab-dependent phagocytosis, which is located downstream of IFN-gamma production, is important as an effector mechanism to eliminate PRBC in blood-stage P. berghei XAT infection.

Production of humanized antibody against human high-affinity IgE receptor in a serum-free culture of CHO cells, and purification of the Fab fragments

We describe the preparation of Fab fragments of a humanized anti-human high-affinity IgE receptor (Fc epsilonRIalpha) antibody potentially useful for treatment of IgE-mediated allergic diseases. IgE-binding capacities of sixteen combinations of light and heavy chains of four recombinant anti-Fc epsilonRIalpha antibodies, chimeric CRA2, humanized CRA2, chimeric CRA4, and humanized CRA4, were compared. A combination in which both chains were of humanized CRA2 had the highest activity. Stable transfectant clones of four kinds of host cells expressing recombinant antibodies were established. CHO-K1 cells were the most productive. Serum-free media suitable for culture of the stable CHO-transfectant clones were screened. The concentration of the humanized CRA2, which the most productive clone secreted into the chosen serum-free medium, was approximately 100 microg/ml. A procedure for the purification of the antibody, papain-digestion, and purification of Fab fragments was established. The highly purified humanized Fab fragments are suitable for use to examine their in vivo activity and immunogenicity in primates.

Type 2 segmental manifestation of disseminated superficial porokeratosis showing a systematized pattern of involvement and pronounced cancer proneness

Nine tumors of squamous cell carcinoma developed in a 61-year-old Japanese woman with linear porokeratosis. She had disseminated superficial porokeratosis, but a linear arrangement of pronounced lesions was found only on the left side of the body, and all of the tumors arose on the linear lesions on the left side of the body. Some of her family members had disseminated superficial porokeratosis. This case may represent a type 2 segmental manifestation of disseminated superficial porokeratosis showing a systematized pattern of involvement and pronounced cancer proneness.

Effects of site-directed mutagenesis in the cysteine residues and the N-glycosylation motif in recombinant Der f 1 on secretion and protease activity

BACKGROUND

The group 1 allergens from mite feces, which belong to the papain-like cysteine protease family, are the most significant in-door allergens. In this study, we analyzed the contribution of the cysteine residues and N-glycosylation in Der f 1, the group 1 allergen from Dermatophagoides farinae, to secretion and maturation by using systems for expression of recombinant Der f 1 (rDer f 1).

METHODS

The rDer f 1 and its mutants were expressed in yeast Pichia pastoris and insect SF9 cells. Secretion of their proforms was checked by SDS-PAGE or immunoblotting. Protease activities of the secreted proform of a mutant and the mature form were compared with that of native Der f 1.

RESULTS

The proform of a mutant Der f 1, pro-N53Q, whose consensus motif for N-glycosylation was disrupted, was not secreted in insect SF9 cells although secreted in P. pastoris. Indirect evidence was obtained to support the disulfide bond formation between Cys4 and Cys118, which were not conserved in papain. A mutant for Cys35 in the catalytic site of the cysteine protease, pro-C35S/N53Q, was secreted, but the other mutants for cysteines concerning intramolecular disulfide bonds were not secreted in P. pastoris. The prosequence of pro-C35S/N53Q was removed by an in vitro activation process. The mature C35S/N53Q showed low protease activity.

CONCLUSION

N-glycosylation is essential for secretion in insect SF9 cells but not in P. pastoris. Disulfide bonds are essential for secretion in P. pastoris. A mutation in the catalytic site, C35S, is not completely critical to removal of the prosequence and protease activity. The findings are useful for future design of recombinant products for application in immunotherapy.

Lyn is essential for fcgamma receptor III-mediated systemic anaphylaxis but not for the Arthus reaction

The Src family kinase Lyn initiates intracellular signal transduction by associating with a variety of immune receptors such as antigen receptor on B cells and high-affinity Fc receptor (FcR) for immunoglobulin Ig(E) (FcepsilonRI) on mast cells. Involvement of Lyn in the IgE-mediated immediate-type hypersensitivity is well documented, but the physiological significance of Lyn in IgG-dependent, type III low-affinity FcR for IgG (FcgammaRIII)-mediated responses is largely unknown. In this study, we generated a double-mutant mouse strain deficient in both type II FcR for IgG (FcgammaRIIB) and Lyn to exclude any involvement of inhibitory signaling by FcgammaRIIB, which otherwise downregulates FcgammaRIII-mediated cellular responses. FcgammaRIIB-deficient but Lyn-sufficient mice served as controls. The Lyn deficiency attenuated IgG-mediated systemic anaphylaxis in vivo, and significantly reduced calcium mobilization and degranulation responses of bone marrow-derived mast cells (BMMCs) in vitro. However, we found that either interleukin 4 or tumor necrosis factor alpha release by BMMCs was comparable to that from Lyn-deficient and control mice, and the reverse-passive Arthus reaction was equally induced in both mutant mice, indicating that Lyn is not involved in the onset of the IgG-mediated, FcgammaRIII-dependent late phase responses of mast cells. These findings provide us with insight into distinct signaling mechanisms in mast cells underlying the development of diverse pathologies as well as a therapeutic potential for selective treatment of allergic disorders.

Reactivities of mutants of a major house dust mite allergen Der f 2 to mouse anti-Der f 2 monoclonal antibodies analyzed by immunoblotting

A total of sixteen recombinant variants of a major house dust mite allergen Der f 2, the wild-type Der f 2, six cysteine mutants, six proline mutants, and three lysine mutants, were expressed in Escherichia coli. The cells were solubilized and run on SDS-PAGE under reducing conditions. Epitopes for five mouse anti-Der f 2 monoclonal antibodies, 1B2, 7C10, 13A4, 15E11, and 18G8, to the recombinant Der f 2 variants were characterized by immunoblot analysis.

Cloning and expression of cDNA encoding the complete prepro-form of an isoform of Der f 1, the major group 1 allergen from house dust mite Dermatophagoides farinae

cDNA clones encoding a major house dust mite allergen, Der f 1, were isolated from a Dermatophagoides farinae cDNA library by plaque immunoscreening using rabbit anti-Der f 1 serum. The sequences cover the complete open reading frame encoding the prepro-form. The sequence is different from previously reported cDNA of Der f 1 in six bases and the encoded amino acid sequence is different in two residues. Pro-forms of Der f 1 and its mutant, in which the N-glycosylation motif was disrupted, expressed in Pichia pastoris were converted to the mature forms by an in vitro activation process and they showed significant IgE-binding. The biologically active rDer f 1 molecules would be useful for diagnostic testing and allergen-specific immunotherapy. In contrast, Der f 1 directly expressed in Escherichia coli without the prosequence had very low IgE binding. The hypoallergenic Der f 1 polypeptide could be useful for safer and more effective immunotherapy.

Functional association of CD9 with the Fc gamma receptors in macrophages

CD9, a member of the tetraspan family of proteins, is highly expressed on macrophages. Although a clear function for the molecule has yet to be described, we have found that the anti-CD9 mAb activates mouse macrophages. The rat anti-CD9 mAb, KMC8.8, but not the F(ab')(2), induced tyrosine phosphorylation of proteins including syk and cbl and induced cell aggregation in the mouse macrophage cell line, J774, suggesting that co-cross-linking of CD9 and Fc gamma R was required for the signal. Co-cross-linking of CD9-Fc gamma R with KMC8.8 on macrophages from three different FcR-deficient mice, FcR gamma-chain(-/-), Fc gamma RIIB(-/-), and Fc gamma RIII(-/-), revealed that Fc gamma RIII is specific and crucial for syk phosphorylation. Although both KMC8.8 and the anti-Fc gamma RIIB/III mAb, 2.4G2, evoked similar phosphorylation patterns, only KMC8.8 induced cell aggregation. Additionally, KMC8.8 treatment led to reduce levels of TNF-alpha production and p42/44 extracellular signal-related kinase phosphorylation relative to 2.4G2 stimulation. Immunofluorescence staining showed that co-cross-linking of CD9-Fc gamma R with KMC8.8 induced filopodium extension before cell aggregation, which was followed by simultaneous colocalization of CD9, Fc gamma RIIB/III, Mac-1, ICAM-1, and F-actin at the cell-cell adhesion site. Moreover, KMC8.8 treatment of Fc gamma R-deficient macrophages revealed that the colocalization of CD9, Fc gamma RIII, Mac-1, and F-actin requires co-cross-linking of CD9-Fc gamma RIII, whereas co-cross-linking of CD9-Fc gamma RIIB induced the colocalization of only CD9 and Fc gamma RIIB. Our results demonstrate that co-cross-linking of CD9 and Fc gamma Rs activates macrophages; therefore, CD9 may collaborate with FcRs functioning in infection and inflammation on macrophages.

A comparative vibrational and NMR study of cis-cinnamic acid polymorphs and trans-cinnamic acid

The IR and Raman spectra of the two polymorphic forms (58 degree- and 68 degree-forms) of cis-cinnamic acid were measured, and the spectral differences discussed on the basis of the crystal structures of the two forms. The IR bands related to the COOH group differ in the frequencies and band shape, reflecting differences in the hydrogen bonding between the two modifications. These spectra were compared with those of trans-cinnamic acid. The IR, Raman, and NMR spectra of the isotopic compounds, including the deuterated and 13C analogs of the cis and trans acids, were also recorded in the solid state and in solution to confirm the spectral assignments.

Expression of humanized Fab fragments that recognize the IgE-binding domain of human Fc(epsilon)RIalpha in COS and CHO cells

Interfering with the binding of IgE to high-affinity IgE receptor alpha chain (Fc(epsilon)RIalpha) is a straightforward strategy for the specific prevention of the IgE-mediated allergic reaction specifically. A Fab fragment (Fab) of a humanized antibody against the membrane proximal IgE-binding domain of human Fc(epsilon)RIalpha inhibits the release of histamine from human basophils. We established an efficient expression system in which to produce directly the humanized anti-human Fc(epsilon)RIalpha Fabs without papain-digestion of the whole antibody. Four Fabs with different C-termini of CH1 were expressed directly in COS-7 cells transfected with expression vectors with or without the Fc gene downstream of a stop codon inserted within the hinge gene. The secretion of Fabs when transfected without the Fc gene was remarkably enhanced compared to that when transfected with the Fc gene. The ability of Fabs to inhibit IgE-Fc(epsilon)RIalpha binding when transfected without the Fc gene was equivalent to that of purified Fab prepared by papain-digestion of the whole antibody. No significant differences among the four Fabs were observed in secretion or activity. Clones of CHO-transfectant cells that secreted the Fabs constitutively were acclimatized to a serum-free medium. Analysis of the binding interface between the Fab and human Fc(epsilon)RIalpha will provide useful information for the design of therapeutic reagents for allergy and asthma.

Biologically active recombinant forms of a major house dust mite group 1 allergen Der f 1 with full activities of both cysteine protease and IgE binding

BACKGROUND

Group 1 allergens from mite faeces, Der f 1 and Der p 1, are the most significant in-door allergens. Therefore, they are the most important component in the standardization of house dust mite extract for diagnosis and allergen-specific immunotherapy (AIT). Although their cDNAs have been cloned, efforts to prepare biologically active recombinant forms in expression systems using bacteria or yeast have failed.

OBJECTIVE

Our purpose is to establish an efficient system to prepare recombinant Der f 1(rDer f 1), identical in quality to native Der f 1.

METHODS

The preproforms of Der f 1 and a mutant N53Q, whose consensus motif for N-glycosylation was disrupted, were expressed in yeast Pichia pastoris. Cysteine protease activity and IgE reactivity were analysed using synthetic substrates and by RAST-EIA, respectively.

RESULTS

The proforms of the two rDer f 1 molecules were efficiently secreted into culture medium. Their prosequences were removed autocatalytically by dialysis against acidic buffer. Although the wild-type rDer f 1 was more highly glycosylated than native Der f 1, N53Q had almost the same apparent molecular weight as native Der f 1 on SDS-PAGE. Both the protease and IgE binding activities of the mature rDer f 1 molecules were the same as those of native Der f 1, whereas the proforms had no or markedly reduced activities.

CONCLUSION

The efficient system to prepare active rDer f 1s established in this study is useful for diagnosis and standardized AIT for house dust mite allergy. Furthermore, the system would be a tool for analysis of IgE epitopes, determination of tertiary structure, allergen engineering for safer and more effective AIT, resolving the relation between the enzymatic activity and pathogenesis, and the development of therapeutic inhibitors.