A 2,7-diamino-1,4,8-triazanaphthalene derivative selectively binds to cytosine bulge DNA only at a weakly acidic pH.

The synthesis and properties of 2,7-diamino-1,4,8-triazanaphthalene (azaDANP) are described. AzaDANP is protonated only at a weakly acidic pH to bind to the cytosine bulge DNA duplex selectively. Upon binding of azaDANP to the cytosine bulge DNA, a new absorption band at 407 nm appears, and the absorption change of azaDANP on binding to the target is very sensitive to environmental pH with a bell-shaped pH-absorption profile.

Antigen presentation in the murine T-lymphocyte proliferative response. I. Requirement for genetic identity at the major histocompatibility complex.

A method is described for stimulating proliferation in primed populations of murine T lymphocytes using antigen bound to mitomycin-C-treated spleen cells. This form of antigen presentation appears to be an active process because heat-killed spleen cells are ineffective, and because genetic similarity at the major histocompatibility complex (MHC) between the responder T cells and the presenting spleen cells is required for effective interactions. At all times examined, from day 3 to day 6 of the proliferative response, syngeneic spleen cells presented antigen better to peritoneal exudate T-lymphocyte-enriched cells (PETLES) than semisyngeneic F(1) spleen cells, which in turn could present antigen better than totally allogeneic spleen cells. Spleen cell mixing experiments demonstrated that these genetic restrictions were not the result of suppression by the ongoing mixed lymphocyte reactions (MLR) in the allogeneic and F(1) cases. Furthermore, incompatibility at the Mls locus generated a strong MLR but failed to prevent antigen presentation if the spleen cells and PETLES were compatible. Genetic mapping studies demonstrated that compatibility at only the I-A subregion of the MHC was sufficient for effective presentation of the antigen, dinitrophenylated ovalbumin. Compatibility at only the K region, or the K and D regions was not sufficient. These results support the concept that functional activation of primed, proliferating T lymphocytes requires the participation of gene products coded for by the I region of the MHC. This conclusion is consistent with a growing body of evidence which suggests that most T cells recognize antigen in association with MHC gene products.

Gene complementation in the T-lymphocyte proliferative response to poly (Glu55Lys36Phe9)n. A demonstration that both immune response gene products must be expressed in the same antigen-presenting cell.

The immune response (Ir) to the random copolymer GLphi depends upon the function of two Ir genes, Ir-GLphi-beta[beta] and Ir-GLphi-alpha[alpha], mapped to the I-A and I-E/C subregions of the major histocompatibility complex, respectively. In this paper, the site(s) of expression of the products of these two Ir genes was examined by evaluating T-lymphocyte proliferative responses of bone marrow radiation chimeras. Chimeras were created in [alpha+beta- X alpha-beta+]F1 responder mice by lethal irradiation and reconstitution with a mixture of bone marrow cells from both parental strains. These chimeras failed to respond to GLphi, although they were capable or responding to the much weaker antigens, (T,G)-A--L, TEPC-15, pigeon cytochrome c, and (H,G)-A--L. This failure to respond to GLphi was shown not to be the result of a cryptic mixed lymphocyte reaction, as similar chimeras created in (alpha+beta+ X alpha-beta+)F1 mice responded well to GLphi, although they possessed almost the same potential histoincompatibility. Furthermore, the lack of response to GLphi could not be attributed to a general failure of the two parental cell types in the chimeras to collaboratc with each other, as each chimeric parental cell type could respond to dinitrophenyl conjugated ovalbumin presented on nonimmune spleen cells from the other parent. Thus, the failure of low responder parental into F1 high responder chimeras to generate an immune response to GLphi suggests that immune competence for this antigen requires at least one cell type in the immune system to express gene products of both the Ir-glphi-alpha and -beta genes, i.e. one cell must be of high responder genotype. The the antigen-presenting cell is one such cell type was shown by experiments in which GLphi-primed T lymphocytes from responder F1 mice were stimulated with antigen bound to nonimmune spleen cells. Only spleen cells from responder F1 and recombinant mice could present GLphi. Neither of the two complementing nonresponder parental spleen cell populations, either alone or mixed together, could present GLphi, although both could present purified protein derivative of tuberculin. This was shown to be the case for T cells positively selected in vitro as well as freshly explanted T cells. Thus, both Ir-GLphi-alpha and Ir-GLphi-beta gene products must be expressed in the same antigen-presenting cell to generate a T-lymphocyte proliferative response to GLphi. The implications of these findings for models of two gene complementation are discussed.

Mitogenic analysis of murine B-cell heterogeneity.

The B-cell mitogens lipopolysaccharide (LPS), Nocardia water-soluble mitogen (NWSM), and dextran sulfate (DxS) react with different subpopulations of B lymphocytes. Selective in vitro killing of cells responding to either LPS or NWSM has little effect on the in vitro response to the other mitogen, although the response to DxS is reduced in both cases. If, after selective in vitro killing, cells are injected into irradiated mice for 2-3 wk before measuring their in vitro mitogen responses, the same specificity pattern is seen. Thus, one is dealing with different B-cell subpopulations rather than different stages of maturation of a single population. Treatment with various alloantisera and complement before measuring the mitogen response to LPS and NWSM shows that (a) whereas all LPS response cells carry surface Ig, a subpopulation of NWSM responsive cells does not; (b) both LPS- and NWSM-responsive cells carry I-A antigens but might not I-E or I-J antigens; (c) all LPS-responsive cells carry I-C antigens, whereas approximately 25% of NWSM responsive cells do not: (d) there is a subpopulation of NWSM-responsive cells carrying neither surface Ig nor I-C antigens and resistant to anti-theta treatment.

Alteration of gap junction proteins (connexins) following lateral fluid percussion injury in rats.

Gap junctions are intercellular channels that mediate the cytoplasmic exchange of small hydrophilic molecules and are formed by a family of integral membrane proteins called connexins (Cxs). Cx43 is expressed predominantly in astrocytes, while Cx36 is expressed in neurons. In this study, we show alteration of Cx43 and Cx36 in the hippocampus after traumatic brain injury in rats. Adult male Sprague-Dawley rats were subjected to lateral fluid percussion injury of moderate severity. Brain coronal sections were used for immunohistochemistry with Cx43 and Cx36 antibodies. Cx43 immunoreactivity was increased in reactive astrocytes in the damaged hippocampus 24 hours after injury, and persisted for 72 hours. On the other hand, Cx36 immunoreactivity increased in CA3 neurons 1 hour after injury, and decreased later. These results indicate that gap junctions might participate in the pathophysiological process after traumatic brain injury.

Enhancement of tumor growth and metastases by medroxyprogesterone acetate in transplanted uterine adenocarcinoma cells of the rat.

PIP: This study describes the effects of medroxyprogesterone acetate on tumor growth and metastases in transplanted uterine adenocarcinoma cells of the rat. High-and-low-tumorigenic cloned cells of Sprague-Dawley rat uterine adenocarcinoma originally induced by 7,12-dimethylbenz (alpha) anthracene in vivo were used. Both were derived from the same parent culture. They were cultured for more than 2 years and both retained almost the same transplantability. Survival rate of cell colonies in vitro was reduced in both lines after progesterone treatment of more than 8 mcg per ml. This reduction was dose dependent. About 1 million cells suspended in .2 ml culture medium were injected sc into the interscapular region of isologous newborn rats. At 5 weeks these rats were given .5 mg medroxyprogesterone acetate twice a week for 2 weeks. At 7 weeks they were killed. High-tumorigenic cells produced growing tumors in all newborn rats. About a third of these rats died of metastases during the 7-week observation period. Tumors produced by low-tumorigenic cells grew slowly and occasionally regressed without metastases to the lung. Tumors in female rats were larger than those in males. Enhancement of tumor growth and metastases by this progesterone compound was observed in rats inoculated with low-tumorigenic cells as compared to controls. The enhancement was not significant in tumors produced by high-tumorigenic cells. The progesterone may act immunosuppressively in vivo, or make alterations in environmental conditions of the tumors.^ieng

Prediction of flood abnormalities for improved public safety using a modified adaptive neuro-fuzzy inference system.

It is widely accepted that an efficient flood alarm system may significantly improve public safety and mitigate economical damages caused by inundations. In this paper, a modified adaptive neuro-fuzzy system is proposed to modify the traditional neuro-fuzzy model. This new method employs a rule-correction based algorithm to replace the error back propagation algorithm that is employed by the traditional neuro-fuzzy method in backward pass calculation. The final value obtained during the backward pass calculation using the rule-correction algorithm is then considered as a mapping function of the learning mechanism of the modified neuro-fuzzy system. Effectiveness of the proposed identification technique is demonstrated through a simulation study on the flood series of the Citarum River in Indonesia. The first four-year data (1987 to 1990) was used for model training/calibration, while the other remaining data (1991 to 2002) was used for testing the model. The number of antecedent flows that should be included in the input variables was determined by two statistical methods, i.e. autocorrelation and partial autocorrelation between the variables. Performance accuracy of the model was evaluated in terms of two statistical indices, i.e. mean average percentage error and root mean square error. The algorithm was developed in a decision support system environment in order to enable users to process the data. The decision support system is found to be useful due to its interactive nature, flexibility in approach, and evolving graphical features, and can be adopted for any similar situation to predict the streamflow. The main data processing includes gauging station selection, input generation, lead-time selection/generation, and length of prediction. This program enables users to process the flood data, to train/test the model using various input options, and to visualize results. The program code consists of a set of files, which can be modified as well to match other purposes. This program may also serve as a tool for real-time flood monitoring and process control. The results indicate that the modified neuro-fuzzy model applied to the flood prediction seems to have reached encouraging results for the river basin under examination. The comparison of the modified neuro-fuzzy predictions with the observed data was satisfactory, where the error resulted from the testing period was varied between 2.632% and 5.560%. Thus, this program may also serve as a tool for real-time flood monitoring and process control.

Slow and prolonged activation of the p47 protein kinase during hypersensitive cell death in a culture of tobacco cells

To investigate the involvement of protein kinases in the signaling cascade that leads to hypersensitive cell death, we used a previously established system in which a fungal elicitor, xylanase from Trichoderma viride (TvX), induces a hypersensitive reaction in tobacco (Nicotiana tabacum) cells in culture (line XD6S). The elicitor induced the slow and prolonged activation of a p47 protein kinase, which has the characteristics of a family member of the mitogen-activated protein kinases. An inhibitor of protein kinases, staurosporine, and a blocker of Ca channels, Gd3+ ions, both of which blocked the TvX-induced hypersensitive cell death, inhibited the TvX-induced activation of p47 protein kinase. Moreover, an inhibitor of serine/threonine protein phosphatase alone induced both rapid cell death and the persistent activation of the p47 protein kinase. Thus, the p47 protein kinase might be a component of the signal transduction pathway that leads to hypersensitive cell death, and the regulation of the duration of activation of the p47 protein kinase might be important in determining the destiny of tobacco cells.

Heat stress-induced modulation of host defense against Toxoplasma gondii infection in mice.

This study examined the effects of burn injury on murine immune response against Toxoplasma gondii infection. Male C57BL/6 mice were divided into 3 groups: T. gondii infection (group T), burn injury (group B), and burn injury followed by T. gondii infection (group BT). The survival of group BT was significantly lower than those of group B and group T. Parasite abundance in the tissues was determined by quantitative competitive-polymerase chain reaction. Group BT exhibited significantly higher numbers of T. gondii than group T. Antibody production against T.g.HSP30 in group BT was significantly lower than that in group T, whereas no significant difference was observed in SAG1-specific antibody production. Delayed-type hypersensitivity (DTH) specific for 2,4-dinitrofluorobenzene (DNFB) of both group B and group BT was significantly lower than that of group T. One week after infection, serum interferon-gamma (IFN-gamma) and interleukin (IL)-10 levels in group BT were significantly lower, whereas serum IL-6 levels were significantly higher than in group T Serum TNF-alpha levels in both group T and group BT were elevated at 1 wk after infection, although there was no significant difference between them. Serum IFN-gamma, IL-10, and TNF-alpha levels in group B were not elevated during the experimental term. In conclusion, the impaired antigen-specific antibody production and DTH response, together with the modulated patterns of cytokine responses, seemed to be strongly involved in the development of burn-induced immunosuppression and the consequent increased susceptibility to T. gondii infection in mice.

Immunologic analysis of cerebrospinal fluid lymphocytes in Vogt-Koyanagi-Harada disease.

In this study, we focused upon the immunologic aspects of Vogt-Koyanagi-Harada disease (VKH) by comparing the cytotoxic activity of peripheral blood leukocytes (PBL) to that of cerebrospinal fluid leukocytes (CSFL) against the human melanoma cell line (P-36) and the human cervical carcinoma cell line (HeLa-S3). The PBL from patients with VKH showed significant cytotoxic activity against P-36 (P less than 0.01), but did not show cytotoxic activity against HeLa-S3. The CSFL showed significantly weaker cytotoxic activity against P-36 compared to that of PBL (P less than 0.02). We also analyzed the cell membrane surface markers applying monoclonal antibodies on PBL and CSFL. The percentage of OKT8+ (CD8: T cytotoxic/suppressor lymphocytes) cells was significantly lower in CSFL than in PBL (P less than 0.05). There was a tendency toward a higher percentage of HLA-DR+ cells (B lymphocytes, monocytes, macrophages, and activated T lymphocytes) and a higher ratio of OKT4+/8+ cells (CD4/CD8: T helper/inducer lymphocytes/T cytotoxic/suppressor lymphocytes) in CSFL from patients with VKH than in their PBL (P less than 0.1).

Dominance of activated T cells and interleukin-6 in aqueous humor in Vogt-Koyanagi-Harada disease.

PURPOSE: To determine the immunopathologic role of the lymphocytes and lymphokines in aqueous humor (AH) of patients with Vogt-Koyanagi-Harada disease (VKH). METHODS: The distribution of leukocyte subsets in the peripheral blood and AH was examined using fluorescein isothiocyanate-conjugated monoclonal antibodies. The levels of lymphokines, such as interleukin-2 (IL-2) and interleukin-6 (IL-6), in the sera, AH, and cerebrospinal fluid from the patients with VKH were determined using an enzyme-linked immunosorbent assay. RESULTS: T cells constituted the majority of lymphocytes within AH. The value for CD4+ cells (helper/inducer T lymphocytes) in AH was 51.7% +/- 14.9% (mean +/- SD) and that for CD8+ cells (cytotoxic/suppressor T lymphocytes) was 31.1% +/- 13.0%. The percentage of HLA-DR+ cells (B lymphocytes, monocytes, macrophages, and activated T lymphocytes) in AH (50.8% +/- 24.9%) significantly exceeded (P < 0.001) that in blood (13.1% +/- 4.2%). The percentage of CD8+ cells in AH from three patients with the delayed type of VKH rose during their clinical course. The level of IL-6 was significantly elevated in AH from the patients with VKH. The level of IL-6 in AH correlated with the number of lymphocytes in AH, and it reflected the severity of the inflammatory response in AH of patients with VKH. The level of IL-2 in the sera, AH, and cerebrospinal fluid was in the normal range. CONCLUSIONS: Aqueous humor lymphocytes from the patients with VKH were more activated than were peripheral blood lymphocytes. IL-6 may play an important role as an inflammatory mediator in VKH. It may be useful to analyze the lymphocyte subsets and the levels of lymphokines, especially of IL-6, at the site of inflammation in uvea to improve the criteria for assessing the prognosis of VKH.

Serological cross-reactivity of murine allo-anti-Ias antibody with the molecule on human antigen-presenting cells.

Murine allo-anti-IaS (A.TL anti-A.TH) antibody cross-reacted with human B-cells and antigen-presenting cells, while the antibody did not cross-react with human T-cells, to be precise, PPD-specific proliferative T-cells. Furthermore, the murine allo-anti-IaS antibody could inhibit the PPD-specific responses of human PBL. Thus, the murine allo-anti-IaS antibody affixes on the Ia-like molecule of human antigen-presenting cells in PPD-specific responses. A genetic mapping study of the serological cross-reactive antibody, by absorbing with the spleen cells from B10.S(9R), A.TH, A.TL and SJL mice in order to determine the specificities for the I subregions of the H-2, revealed that the serological cross-reactivity with human PBL was caused by the anti-I-AS antibody.

Analysis of function of a human antigen-presenting cell by xenogeneic interaction with mouse T cells.

A human B cell line, ARH, was transfected with a murine major histocompatibility complex class II gene (I-A(k)). One of the transfectants, ARH5.5, which strongly expresses I-A(k) molecules was found to be capable of presenting soluble antigens to I-A(k)-restricted, antigen-specific murine helper T cell (Th) clones. When ARH5.5 was treated with either chloroquine or paraformaldehyde prior to the antigen pulse, it failed to present a protein antigen, ovalbumin, but retained the ability to present a peptide, indicating that the presentation was dependent on processing. The xenogeneic interaction of co-stimulatory molecules on the human antigen presenting cell (APC) and the murine Th cell was assessed by using antibodies against adhesion molecules. We found that the xenogeneic interaction of LFA-1/ICAM-1 acted as a strong co-stimulator of the antigen presentation by ARH5.5, while that of CD2/LFA-3 had only little stimulatory effect. These results suggest that the interaction between some of the adhesion molecules on APC and Th can cross the species barrier. The experimental system presented here is simple and useful for analyzing human APC function, separately from T cell function, especially when the dysfunction of APC associated with viral infection with human tropism is considered.

Phylogenetic hierarchy of antigen-presenting ability in antigen-specific T cell activation.

The phylogenetic hierarchy of antigen-presenting ability was shown to exist in xenogeneic mouse, rat and human T cell-antigen-presenting cell (APC) interaction. The antigen-presenting ability of human APC is dominant over that of rat APC and the ability of rat APC is dominant over that of mouse APC. The HLA-DR molecule was shown to function for antigen presentation to PPD-specific autologous human and xenogeneic murine T cells.

Cellular FITC-linked immunospecific assay (cell-FLISA) for detection of monoclonal antibodies against cell-surface antigens.

A cellular fluorescein isothiocyanate (FITC)-linked immunospecific assay (Cell-FLISA) has been established using the recently developed fluorophotometer for microplates. In the Cell-FLISA system, monoclonal antibodies specific for the surface antigens of live cells are detected by measuring the fluorescence intensity of an FITC-labeled second antibody: goat anti-mouse immunoglobulin antibody. It takes only 2 min to count 96 samples in microplate wells using the fluorophotometer for microplates. Moreover, by this system, the analysis is finished within 2 hr. Thus, the Cell-FLISA system has advantages in screening a large number of samples, such as hybridoma cell lines secreting monoclonal antibodies against cell-surface antigens.

Toxoplasma gondii Hsp70 as a danger signal in toxoplasma gondii-infected mice.

Toxoplasma gondii Hsp70, T gondii Hsp30/bag1, and surface antigen 1 messenger RNAs were shown to be useful in analyzing stage conversion of T gondii between bradyzoites and tachyzoites. The high-level expression of T gondii Hsp70 was correlated with mortality in interferon-gamma knockout mice infected with T gondii. Tgondii Hsp70 inhibited the induction of nitric oxide release by peritoneal macrophages of T gondii-infected mice. These findings identify T gondii Hsp70 as a danger signal during lethal, acute T gondii infection.

Non-H-2 involvement in antigen-specific T cell proliferative responses. I. Different blocking effect of anti-class II monoclonal antibodies between B6 and BALB.B mice on antigen-specific T cell activation.

Two monoclonal antibodies (IAb1 and D2A2 mAbs) to I-Ab molecule were shown to have different inhibitory effects between B6 and BALB.B mice in antigen-specific T cell activation. Antigen-specific T cell proliferative responses of B6 were blocked by IAb1 mAb but not by D2A2 mAb, whereas those of BALB.B were blocked by both IAb1 and D2A2 mAbs. The different blocking effect of D2A2 mAb between B6 and BALB.B is attributed to the APC level but not responding T cell repertoires, because antigen-specific proliferative responses of (B6XBALB.B)F1 T cells stimulated by BALB.B APC but not by B6 APC were blocked by D2A2 mAb. These data indicate that not only H-2 but also non-H-2 genes participate in antigen-specific activation of T cells by APC.

Interspecies cross-reactivity of Class II antigen of MHC determined by syngeneic, allogeneic and xenogeneic B and T cells.

Although this chapter ought to summarize the role of MHC antigens in T cell activation, the immunobiological meaning of the polymorphism of Class II antigens, as well as that of Class I antigens, is still unresolved. The antigen-presenting ability of human APC is dominant over that of murine APC in the stimulation of antigen-specific xenogeneic T cells. In addition, xenoreactive murine T cells specific for human PBL failed to recognize the polymorphic determinant of Class II antigens of human MHC. On the basis of the data, Class II antigens may be seen to have some role as antigen-presenting molecules rather than as restricting molecules, at least, in the xenogeneic APC-T cell interaction or the xenogeneic MLR responses. These data together with the fact that the linkage disequilibrium found among the various groups of alleles encoding Class I and II antigens making up an MHC haplotypes suggest that the MHC may play a key role during evolution. These studies using xenogeneic cell interaction may shed some light on the immunobiological function of polymorphism of MHC antigens in the mechanisms of T cell activation, and the evolutional history of the polymorphism of the NHC in self or not-self recognition by T cells.

Limited uptake of foreign materials by resident macrophages in murine ovarian tissues.

In the present study, the distributions of exogenously administered horseradish peroxidase (HRP) and colloidal carbon in gonadal tissues were observed in both male and female mice using light microscopy. HRP was injected intravenously and colloidal carbon was directly injected into the gonadal parenchyma. Thereafter, the gonads were obtained for histological examination. The results showed that staining of HRP and carbon was detected in the ovaries at a low level. In contrast, much staining was observed in the interstitial cells of the testes for a long period. This suggests that ovarian tissues are less active in the uptake of exogenous materials than testicular tissues in vivo. However, immunohistochemical examination using anti-macrophage antibodies revealed that the ovaries contained a large number of macrophages, as did the testes, under normal conditions. Therefore, the results indicate that resident macrophages in the ovaries exhibit weak endocytic activity of foreign materials in vivo.

Generation of self HLA-DR-specific CD3+CD4-CD8+ cytotoxic T cells in chronic graft-versus-host disease.

To analyze the mechanism of chronic graft-versus-host disease (GVHD) characteristic of autoimmune disease, we used a cell-mediated lympholysis assay to study the autoreactivity of PBL from two patients after MHC-matched BMT. Our data indicate the induction of CD3+CD4-CD8+ autoreactive cytotoxic T lymphocytes (CTL) in the one patient with chronic GVHD and an important role for allo-non-MHC (minor histocompatibility) antigen-specific CD3+CD4+CD8- helper T cells in this induction. Experiments using HLA-DR gene-transfected mouse L cells as target cells and blocking assays with anti-HLA class I and class II antibodies provided evidence that autoreactive CTL recognized HLA-DR antigen on autologous cells. Analysis of antigen-specific T cell proliferative responses in these patients to examine the effect of self HLA-DR-specific CTL on the antigen presenting cell (APC)-T cell interaction suggested that donor bone marrow-derived self HLA-DR-specific CTL are responsible for the decreased antigen-presenting ability of the patient's APC. These results suggest a new interpretation of the induction mechanism of chronic GVHD and its associated immunosuppression after MHC-matched BMT based on diminished APC function.