Evidence that the ATP-induced increase in vasomotion of guinea-pig mesenteric lymphatics involves an endothelium-dependent release of thromboxane A2

1. Experiments were made to investigate mechanisms by which adenosine 5'-trisphosphate (ATP) enhanced vasomotion in mesenteric lymphatic vessels isolated from young guinea-pigs. 2. ATP (10-8 - 10-3 M) caused a concentration-dependent increase of perfusion-induced vasomotion with the endothelium mediating a fundamental role at low ATP concentrations (10-8 - 10-6 M). 3. The response to 10-6 M ATP showed tachyphylaxis when applied at intervals of 10 min but not at intervals of 20 or 30 min. 4. Suramin (10-4 M) or reactive blue 2 (3x10-5 M) but not PPADS (3x10-5 M) abolished the excitatory response to 10-6 M ATP confirming an involvement of P2 purinoceptors. 5. The excitatory response to 10-6 M ATP was abolished by treatment with either pertussis toxin (100 ng ml-1), antiflammin-1 (10-9 M), indomethacin (3x10-6 M) or SQ29548 (3x10-7 M), inhibitors of specific G proteins, phospholipase A2, cyclo-oxygenase and thromboxane A2 receptors respectively. 6. ATP simultaneously induced a suramin-sensitive inhibitory response, which was normally masked by the excitatory response. ATP-induced inhibition was mediated by endothelium-derived nitric oxide (EDNO) as the response was abolished by NG-nitro-L-arginine (L-NOARG; 10-4 M), an inhibitor of nitric oxide synthase. 7. We conclude that ATP modulates lymphatic vasomotion by endothelium-dependent and endothelium-independent mechanisms. One of these is a dominant excitation caused through endothelial P2 purinoceptors which because of an involvement of a pertussis toxin sensitive G-protein may be of the P2Y receptor subtype. Their stimulation increases synthesis of phospholipase A2 and production of thromboxane A2, an arachidonic acid metabolite which acts as an endothelium-derived excitatory factor.

Role of macrophage protection in the development of murine AIDS

Macrophages play a key role in AIDS pathogenesis and thus controlling infectivity and viral replication in these cells is a key issue in any antiretroviral therapy. In the present study, using a murine model of AIDS, we evaluated new therapeutic approaches specifically designed for the protection of macrophages. Based on previous observations, we took advantage of the unique ability of autologous erythrocytes to deliver drugs selectively to macrophages. The antiviral drugs selected were a new homodimer of AZT (AZTp2AZT) and reduced glutathione (GSH). The addition of an oral drug for the protection of lymphocytes (i.e., AZT) was also investigated. C57BL/6 mice infected with the retroviral complex LP-BM5 were treated with GSH-loaded erythrocytes, GSH-loaded erythrocytes plus oral AZT, or GSH/AZTp2AZT-loaded erythrocytes plus oral AZT. The treatments including AZT and erythrocytes loaded with GSH alone or with GSH plus AZTp2AZT provided similar results and were most effective in inhibiting the progression of MAIDS; they reduced splenomegaly, lymphadenopathy, and hypergammaglobulinemia by about 70%, 90% and 83%, respectively, when compared with infected animals at 10 weeks postinfection. Evaluation of BM5d proviral DNA content in infected organs revealed that both treatments were able to almost completely protect most infected animals. They were also able to normalize the blood lymphocyte phenotype and to restore the responses of T and B cells to mitogens significantly. Treatment with GSH-loaded erythrocytes alone did not provide significant results for most parameters investigated, but a marked reduction in proviral DNA content was obtained in infected organs, including the brain. The results reported in this paper confirm the important role of macrophages in retroviral infection and moreover prove that erythrocytes, by selectively protecting these cells, strongly affect MAIDS progression. Furthermore, the combination of GSH- or GSH/AZTp2AZT-loaded erythrocytes with an oral nucleoside analogue (AZT) for the protection of lymphocytes provides additive responses in all the parameters investigated.

Panax ginseng blocks morphine-induced thymic apoptosis by lowering plasma corticosterone level

The effects of Panax ginseng on morphine-induced immune suppression were studied. Morphine (20 mg/kg, SC, 4 days) decreased body weight increment rate and caused atrophy of thymus and spleen. These changes were partly reversed by concomitant administration of ginseng total saponin (GTS, 100 mg/kg, oral, 9 days). Morphine elevated the serum corticosterone level and caused the DNA fragmentation of thymocytes. These sequential events were completely blocked by a concomitant administration of GTS. Flow cytometry analysis showed that GTS specifically blocked morphine-induced apoptosis of thymocytes.

Reversibility of the pathological changes in the follicular dendritic cell network with treatment of HIV-1 infection

Over the course of HIV-1 infection, the lymphoid follicles where the humoral immune response is generated initially increase in size and number and then progressively involute. In advanced disease, the network of the processes of follicular dendritic cells (FDCs) that serve as antigen repositories and anatomical substrate for B and T cells and antigen to interact is destroyed, contributing to the breakdown of the immune system. Because destruction of FDCs is associated with deposition of HIV-1, and much of the virus can be cleared from the network with antiretroviral therapy, we investigated the reversibility of damage. We measured the immunohistochemically stainable FDC compartment by quantitative image analysis, and we documented changes in this compartment at different stages of disease. We show that treatment, initiated even at advanced stages of HIV-1 disease, can slowly reverse pathological changes in the FDC network.

Immunotoxicity of the anticancer drug CI-994 in rats: effects on lymphoid tissue

CI-994 (acetyldinaline) is an investigative oral anticancer drug currently in clinical trials. To characterize the effects of CI-994 on lymphoid tissue, male rats were administered single oral doses at 0 (vehicle control), 10, 23, and 45 mg/kg and killed up to 7 days after dosing for evaluation of white blood cell differentials, bone marrow differentials, lymphoid tissue weights, and selected histopathology of lymphoid tissue. Statistically significant dose-related reductions in blood lymphocytes (CD-3+, CD-4+, CD-8+, CD-20+), monocytes, neutrophils, and bone marrow lymphoid cells were observed in all drug-treated groups on days 1 and/or 3. Statistically significant reductions in bone marrow myeloid cells were also observed on days 1 and 3 at 23 and 45 mg/kg. Complete or partial reversal of most parameters was evident on day 7. Spleen and/or thymus weights were significantly decreased in the groups administered 23 and 45 mg/kg on days 1, 3, and/or 7. Minor reductions in lymphoid organ weights were noted at 10 mg/kg. Minimal to moderate lymphoid depletion of the spleen and thymus was noted on day 3 in animals dosed at 23 mg/kg. In vitro, CI-994 inhibited mitogen-stimulated blood lymphocyte proliferation with a 50% inhibitory concentration (IC50) value of 3 microM. The results demonstrate that CI-994 can effect lymphoid tissue in rats within 1 day of a single oral dose, that effects are generally reversible within 7 days, and that inhibition of lymphocyte proliferation is a sensitive indicator of CI-994 immunotoxicity in vitro.

[Features of the distribution of lymphoid tissue in the walls of the trachea and principal bronchi after exposure to acetaldehyde vapors]

The present study was aimed to examine the lymphoid tissue in the walls of the trachea and major bronchi following the inhalation of acetaldehyde. Albino Wistar rats, subjected to the action of acetaldehyde 20 and 25 mgm/m3 in concentrations during 2, 4, 6, and 8 hrs were the subject of the experiment. It was established that acetaldehyde action in the wall of trachea and major bronchi results in histotopographical changes of lymphoid structures and increase of relative (%) area of lymphoid tissue in the walls of the above-mentioned organs.

Cimetidine does not influence TIL in breast cancer

Cimetidine is known to have immunomodulatory effects and this study aimed to examine the effect of pre-operative cimetidine treatment on lymphocytic infiltration in n = 72 women with breast cancer randomised to 400 mg bd or placebo for five days presurgery. A combined index was devised by adding infiltrating lymphocyte percentage and lymphoid score. There were no significant differences in circumferential infiltrate and lymphoid follicles in cimetidine treated patients and control patients with breast cancer.

Costimulatory molecules CD80 and CD86 in the rat; tissue distribution and expression by antigen-presenting cells

The CD28-CD80/CD86 costimulatory pathway provides a critical signal for T cell activation. Only recently rat CD80 and CD86 have been cloned and monoclonal antibodies have been generated. In this study we examined the expression of these molecules in lymphoid tissue and on purified subsets of antigen-presenting cells (APC). The target tissue of cyclosporin A-induced autoimmunity, i.e. the skin and tongue, were also examined for expression of CD80 and CD86. Whereas CD80 was hardly detected in the lymphoid tissues, CD86 was clearly expressed by non-lymphoid cells in the thymus, as well as in the secondary lymphoid organs. With respect to lymphoid cells, only germinal center B cells exhibited clear CD86 expression. Phenotypic analysis by flow cytometry revealed that only dendritic cells, both of thymic and splenic origin, expressed the full array of stimulatory molecules required for the proper activation of naive T cells. On development of cyclosporin A-induced autoimmunity, non-professional APC, i.e. epithelial cells, started to express MHC class II, but not the costimulatory ligands CD80 and CD86. However, CD86 staining was observed in the target tissue and was associated with Langerhans cells as well as infiltrating leukocytes. Altogether, our results show that also in the rat strong stimulatory capacity for primary immune responses is associated with the expression of the costimulatory ligands CD80 and CD86. As concluded from the in situ expression CD86 may be the predominant costimulatory ligand early in immune responses.

Effect of dietary fat on lymphocyte proliferation and metabolism

The effect of diets enriched with fat containing different fatty acids on glucose and glutamine metabolism of mesenteric lymph nodes lymphocytes, spleen, and thymus and lymphocyte proliferation was examined. The following fat-rich diets were tested: (1) standard chow (CC); (2) medium chain saturated fatty acids (MS)--coconut fat oil; (3) long chain saturated fatty acids (LS)--cocoa butter; (4) monounsaturated fatty acids (MU)--canola oil (n-9); (5) polyunsaturated fatty acids (PU)--soybean oil (n-6). Of the fat-rich diets tested, MS was the one to present the least pronounced effect. Lymphocyte proliferation was reduced by LS (64 per cent), MU (55 per cent), and PU (60 per cent). Hexokinase activity was enhanced in lymph node lymphocytes by PU (67 per cent), in the spleen by MS (42 per cent), and in the thymus by PU (30 per cent). This enzyme activity was reduced in the spleen (33 per cent) by LS and MU (35 per cent). In the thymus, this enzyme activity was reduced by LS (26 per cent) and MU (13 per cent). Maximal phosphate-dependent glutaminase activity was raised in lymphocytes by MS (70 per cent) and MU (20 per cent). This enzyme activity, however, was decreased in lymphocytes by PU (26 per cent), in the spleen by LS (15 per cent), and in the thymus by MU (44 per cent). Citrate synthase activity was increased in lymphocytes by MU (35 per cent), in the spleen by LS (56 per cent) and MU (68 per cent), and in the thymus by LS (42 per cent). This enzyme activity was decreased in lymphocytes by PU (24 per cent) only. [U-14C]-Glucose decarboxylation was raised by all fat-rich diets; MS (88 per cent). LS (39 per cent), MU (33 per cent), and PU (50 per cent), whereas [U-14C]-glutamine decarboxylation was increased by LS (53 per cent) and MU (55 per cent) and decreased by MS (17 per cent). The results presented indicate that the reduction in lymphocyte proliferation due to LS, LU and PU could well be a consequence of changes in glucose and glutamine metabolism.

Comparative effects of repeated administration of cadmium on kidney, spleen, thymus, and bone marrow in 2-, 4-, and 8-month-old male Wistar rats

Male Wistar rats at 2, 4, and 8 months were given s.c. injections of CdCl2 at doses of 0.5, 1, and 2 mg Cd/kg, 3 days/week, for 4 weeks. Dose-related adverse effects observed at the end of the injections were as follows: decrease in body weight gain, increases in liver, kidney, and spleen weights, decrease in red blood cell counts, and increase in white blood cell counts accountable by an increased percentage of neutrophils in peripheral white blood cells. Essentially, all of these changes were age-related, i.e., the extents of the effects in each age group were in the order of 8- > 4- > 2-month-old rats when compared at the same dose level of Cd. The sensitive indicators of histological changes were increase in hematopoietic cells in bone marrow and fibrous tissue proliferation in the thymus > fibrous tissue proliferation and hyperplasia of lymph follicle in the spleen > renal tubular degeneration. These histological changes became to be marked at lower doses with aging. Dose-dependent increases in total Cd concentrations in the liver, kidney, and spleen were slightly higher with aging, while metallothionein (MT) contents in these organs were induced exactly in the same pattern as Cd concentrations in each organ in various age groups. This study revealed that the adverse effects after repeated administration of Cd on the kidney, spleen, thymus, and bone marrow worsened with increasing animal age and that this phenomenon could not be explained simply by differences in Cd disposition or MT induction in the organs of the different age groups.

Heparan sulfate oligosaccharides require 6-O-sulfation for promotion of basic fibroblast growth factor mitogenic activity

The interaction of heparan sulfate (HS) with basic fibroblast growth factor (bFGF) is influential in enabling the growth factor to bind to its cell surface tyrosine kinase receptor. In this study, we have investigated further the structural properties of HS required to mediate the activity of bFGF in a mitogenic assay. We have prepared a library of heparinase III-generated HS oligosaccharides fractionated by both their size (dp6-dp12) and sulfate content. The ability of these oligosaccharides to activate bFGF in a mitogenic assay was then correlated with their length and disaccharide composition. All octa- and hexasaccharide fractions tested were unable to activate bFGF. Dodeca- and decasaccharide fractions were found to contain both activating and non-activating oligosaccharides, and showed a clear correlation between total sulfate content and the level of activatory activity. Disaccharide analysis of a range of dodeca- and decasaccharide fractions showed that both activating and non-activating oligosaccharides were composed mainly of N-sulfated and IdoA(2S)-containing disaccharides. The only significant difference between activating and non-activating oligosaccharides was the content of 6-O-sulfated disaccharides, in particular the disaccharide IdoA(2S)alpha1,4GlcNSO3(6S). These results show that there is a requirement for 6-O-sulfation of N-sulfated glucosamine residues, in addition to the 2-O-sulfation of IdoA, for the promotion of bFGF mitogenic activity by naturally occurring HS oligosaccharides. Analysis of the structure-activity relationships in the dodecasaccharide fractions in particular, suggests that a minimum bFGF activation sequence exists which is dependent on the positioning of at least one 6-O-sulfate group.

T-2 toxin-induced apoptosis in hematopoietic tissues of mice

We examined T-2 toxin-induced lesions in the bone marrow and splenic red pulp as many as 48 hr after oral inoculation with 10 mg/kg body weight of T-2 toxin in female ICR:CD-1 mice. Histopathologically, the bone marrow and splenic red pulp showed a significant hypocellularity. In the bone marrow, the number of myelocytes significantly decreased due to the loss of immature granulocytes, erythroblasts, and lymphocytes. The nuclei of the remaining cells showing pyknosis or karyorrhexis were positively stained by the TdT-mediated dUTP nick end labeling (TUNEL) method, and these TUNEL-positive cells showed ultrastructural characteristics of apoptosis. With agarose gel electrophoresis, DNA ladders were clearly detected in bone marrow samples. The number of TUNEL-positive cells in splenic red pulp increased earlier than it did in the splenic white pulp. Thus, T-2 toxin induced-lesions in the hematopoietic tissues and in the lymphoid tissues were brought about by apoptosis of component cells. We believe that damage to the hematopoietic microenvironment may also play an indirect role in the induction of apoptosis in the bone marrow.

IgA antibody-forming cell responses in the nasal-associated lymphoid tissue of mice vaccinated by intranasal, intravenous and/or subcutaneous administration

Effects of a single intranasal (i.n.), subcutaneous (s.c.) or intravenous (i.v.) vaccination and their combined vaccination of priming and boosting on a primary and a secondary IgA antibody forming cell (AFC) response were examined in the nasal associated lymphoid tissue (NALT), spleen and popliteal lymph nodes (pLNs) of BALB/c mice. Mice were primed with the vaccine prepared from A/Yamagata/120/86 (H1N1) together with a cholera toxin-adjuvant and boosted with the same vaccine 3 weeks later. Three days after boosting, IgA-AFC responses in each lymphoid tissue were measured as an index of the immunological memory that mediates a secondary IgA-AFC response. Single i.n. vaccination induced a greater primary IgA-AFC response in the NALT not only than that in the spleen or pLNs, but also than that induced by single i.v. or s.c. vaccination. The combination of i.n. priming and i.n. boosting afforded a greater anamnestic IgA-AFC response in the NALT not only than that in the spleen or pLNs, but also than that induced by any other combinations of priming and boosting (i.n.-i.v., i.n.-s.c., s.c.-i.n., s.c.-i.v., and s.c.-s.c.). These results showed that i.n. priming induced a greater primary IgA-AFC response in the NALT and simultaneously induced the immunological memory that mediated a greater secondary-type AFC response following i.n. boosting in the NALT.

Effect of RN-301 immunomodulator on bronchus-associated lymphoid tissue (BALT) in protein depleted rats at weaning

It has been previously demonstrated in Wistar rats that severe protein deprivation at weaning, even after refeeding with a 20% casein diet for 21 days, provokes alterations in IgA+ B cell and T cell populations from gut and GALT (gut associated lymphoid tissue) that are reverted by immunomodulator IM-104. In the present report, we investigate the influence of RN-301 (quite similar to IM-104) given by the oral or subcutaneous route during the protein deprivation period, in the seeding of BALT with IgA+ B and CD5+ T cells. The immunomodulator RN-301 contains LPS from E. coli and membrane and ribosomal fractions of P. acne. Tissue sections of the lower respiratory tract were studied by immunohistochemistry. The immunomodulator RN-301 administered by the oral route favours the significant increase in the seeding of the BALT lamina propria with IgA+ B and CD5+ T cells (p < 0.001). However, the RN-301 given by the subcutaneous route does not favour the repopulation of the BALT lamina propria. The ribosomal fractions from P. acne associated with LPS from E. coli contained in the immunomodulator RN-301 administered by the oral route may rescue the small resting lymphocytes in the gut-associated lymphoid tissue (GALT). This event favours their proliferation and migration to the BALT.

Effect of the administration of fish oil by gavage on activities of antioxidant enzymes of rat lymphoid organs

1. The effect of administration of fish oil by gavage on catalase (CAT), glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities of the lymphoid organs and liver was compared with those of soybean oil and cocoa butter. 2. Fish oil did not affect the activities of SOD and CAT but reduced that of GSH-Px in the spleen. In contrast, cocoa butter reduced the CAT activity in the thymus and liver, and soybean oil decreased CAT activity in the thymus. 3. The content of thiobarbituric acid reactive substances of the lymphoid organs was not modified but was increased in plasma.

Changes in lymphoid tissue after treatment with a gonadotropin releasing hormone antagonist in the neonatal marmoset (Callithrix jacchus)

PROBLEM

The effect of neonatal treatment with a gonadotropin releasing hormone (GnRH) antagonist on the morphology and distribution of lymphocytes in lymphoid tissue of the infant marmoset was examined.

METHOD OF STUDY

From a screened panel of antihuman antibodies for specific immune cells, antibodies for the CD20 and CD3 antigens showed excellent reactivity with marmoset tissue. Five sets of marmoset twins were treated with either the GnRH antagonist or a vehicle from birth, and were euthanized at 7 to 9 (3 sets) or 16 to 20 weeks (2 sets) of age. The spleen, thymus, and inguinal lymph nodes from each animal were processed for immunocytochemistry, and the number of cells expressing the CD20 and CD3 antigens were quantified.

RESULTS

Control twins exhibited high plasma levels of testosterone, characteristic of the neonatal period, whereas testosterone concentrations were reduced (P = 0.001) to detection limits in the GnRH antagonist-treated twins. Microscopic evaluation suggested that treatment reduced the volume and cellularity of the thymic cortex, resulting in a decrease in the cortical-to-medullary ratio. Treatment reduced (P = 0.046) the number of thymocytes expressing the B-cell antigen (CD20) and marginally lowered (P = 0.067) the number expressing the T-cell antigen (CD3) in the thymic medulla. In the spleens of treated animals, periarterial lymphatic sheaths were less prominent on microscopic examination, and there were marginally fewer (P = 0.064) CD3+ cells. Numbers of CD20+ lymphocytes in the peripheral white pulp of the spleen and in the germinal centers of the lymph nodes, or CD3+ cells in the paracortex and germinal centers of the lymph nodes, were not altered by treatment.

CONCLUSION

Neonatal treatment with a GnRH antagonist may alter maturational processes for B and T cells in the thymus and spleen of the marmoset and may deprive the immune system of its normal sensitivity to GnRH at a potentially critical time in development.

Extension of the protocol of OECD guideline 407 (28-day repeated dose oral toxicity test in the rat) to detect potential immunotoxicity of chemicals

To indicate the immunotoxic potential of chemicals the examinations prescribed by OECD Guideline 407 were extended by the following additional toxicological, haematological, histopathological, and immune function examinations: absolute and relative organ weight of spleen, thymus, popliteal lymph nodes, lung and brain; histopathology of thymus, mesenteric lymph nodes, popliteal lymph nodes, bone marrow (femur), Peyer's patches (ileum), lungs and colon; PFC assay (spleen), T cell proliferation and NK cell assay. Two well known immunosuppressants Azathioprine (AZA) and Cyclosporine A (CysA) were chosen as model compounds at a dose range which do not cause visible toxic signs on the animals during a 28 days treatment period. The results show that the applied experimental system is much more sensitive in detection of the immunotoxic potential of these two compounds in a low dose range than the examination required by OECD Guideline 407 are.

[Treatment of primary low-grade gastric lymphomas with eradication of Helicobacter pylori]

There is evidence associating Helicobacter pylori (HP) with both mulosa-associated lymphoid tissue (MALT) and MALT-lymphoma. Recently, three studies including 65 patients have shown that the eradication of HP can lead to regression in about 60-70% of primary low-grade gastric B-cell MALT-lymphomas. Prolonged follow-up will be necessary to see whether these remissions are lasting, and whether eradication of HP in combination with conventional therapy is more effective than either of these treatments alone. Until then we recommend that HP is eradicated in these lymphomas before referral to standard treatment with chemotherapy and/or radiotherapy.

Immunochemical detection and identification of protein adducts of diclofenac in the small intestine of rats: possible role in allergic reactions

Idiosyncratic adverse drug reactions are unpredictable, target multiple organ systems, and often become life-threatening events. Although the causes of idiosyncratic adverse drug reactions are not known in most cases, evidence suggests that they may be mediated through immunological mechanisms. It is generally thought that for a drug to lead to an immune response, it must first become covalently bound to a carrier protein. Since most drugs are unreactive, it is usually a reactive metabolite that is expected to form covalent adducts. However, it is not clear why more people do not develop immune reactions against drug-protein adducts. One possible explanation is that orally administered drugs may lead to oral tolerance in most individuals through mechanisms similar to that found with orally administered antigens. However, very little is known regarding the interaction of drugs with gut-associated lymphoid tissue of the small intestine, where oral tolerance can develop. As an initial step to test this hypothesis, we have investigated whether diclofenac, a commonly used nonsteroidal antiinflammatory drug, can lead to protein adducts in rat small intestine. Diclofenac was administered to rats by gastric gavage. Immunoblot analysis of small intestine homogenates and isolated enterocyte subcellular fractions with drug-specific antiserum revealed 142-, 130-, 110-, and 55-kDa protein adducts of diclofenac. The 142- and 130-kDa adducts of diclofenac were identified as aminopeptidase N (CD13) and sucrase-isomaltase, respectively, by amino acid sequence analyses and by their reactions with protein-specific antibodies. The adducts were localized by immunohistochemistry and found primarily in the mid-villus and villus-tip enterocytes and also in the dome overlying Peyer's patches. Similar adducts were detected immunochemically in villus-tip enterocytes of animals treated with halothane or acetaminophen. These results show that intestinal protein adducts of drugs can be formed in gut-associated lymphoid tissue where they may lead to the down-regulation of drug-induced allergic reactions in many individuals.

Influences of immunosuppressive agents, FK506 and cyclosporin on systemic Candida albicans infection in mice

The effects of the immunosuppressive agents FK506 (tacrolimus) and cyclosporin (CyA) on Candida albicans infection in mice were compared with those of cyclophosphamide. FK506 and CyA did not exacerbate C. albicans infection in mice when the effects were determined on the basis of survival ratio and colony forming units (CFU) in the kidney, although cyclophosphamide (CY) impaired the host defence mechanisms of mice against C. albicans infection. The effects of FK506 and CyA on the body weight of mice, histopathological changes of lymphoid tissues and formation of granulomas in kidney were also studied in comparison with those of CY.

Gut bacterial translocation during total parenteral nutrition in experimental rats and its countermeasure

BACKGROUND

The use of total parenteral nutrition (TPN) is commonly associated with mucosal lining of the intestinal tract, causing degenerative changes within the gut-associated lymphoid tissue (GALT). These phenomena are probably caused by the translocation of indigenous intestinal bacteria into other organs and tissues where they induce infections.

METHODS

Using TPN model rats, this paper looks at the result of the investigation of the action of PSK (proteoglycan), a biological response modifier, which appears to suppress bacterial translocation and maintain local immunity activity.

RESULTS

Culture of mesenteric lymph nodes obtained post-TPN demonstrate a bacterial rate as high as 60%. Immunohistochemical examination indicates a reduction in the number of plasma cells and a decrease in S-IgA production and secretion. A similar reduction in S-IgA within bile and portal venous blood was also confirmed. Continuous oral administration of PSK in a daily dose of 1,000 mg/kg had a protective effect against the degeneration of GALT. A staining in immunocytes of Peyer's patches using immunohistochemical study was performed after administration of PSK and revealed constant levels of MHC-I, MHC-II, T helper cells, and interleukin-2 producing cells, supporting the protective role of PSK against degeneration of GALT with a subsequent reduction in bacterial translocation.

CONCLUSIONS

Proteoglycan can restore the impaired local immunity in the intestinal tract to normal levels and suppression of the bacterial translocation to provide an important function for patients receiving TPN treatment.

Cytochrome P450 1A1 induction in rat lymphoid tissues following in vivo and in vitro exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin requires protein kinase C

The induction of cytochrome P450 1A1 (CYP1A1) is one of the most sensitive responses associated with exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related compounds. The mechanisms that underlie this response are not completely understood, particularly in lymphoid tissues that may be used in biomarker studies in humans. CYP1A1 mRNA expression and enzyme activity (ethoxyresorufin-o-deethylase, EROD) were investigated in rat thymus and spleen and isolated thymocytes and splenocytes in culture. Thymus- or spleen-derived microsomes from rats treated in vivo with TCDD showed induced EROD activity after as little as 12 h following a single exposure to TCDD (5 microg/kg body weight). Resting rat thymocytes in culture had detectable levels of EROD activity and CYP1A1 mRNA expression which increased following in vitro exposure to > or = 0.1 nM TCDD for 24 or 48 h. Interestingly, concomitant in vitro exposure of rat thymocytes to TCDD and the mitogen concanavalin A (Con A) inhibited the induction of EROD activity, which is in contrast to the response of cultured human peripheral blood lymphocytes (Landi et al., 1994; Pharmacogenetics 4, 242 246). Resting rat splenocytes in culture had no detectable EROD activity and CYP1A1 activity could not be induced by in vitro TCDD exposure, in the presence or absence of Con A. These results suggest that the relative maturation state of the cells is important in regulating the expression of CYP1A1, since splenocytes represent a more mature population of B and T lymphocytes. TCDD-induced CYP1A1 expression in cultured rat thymocytes was inhibited by the addition of calphostin C, a specific protein kinase C (PKC) inhibitor, suggesting a role for PKC as a second messenger in the CYP1A1 induction pathway. In vivo co-exposure with phorbol-myristate-acetate (PMA) and TCDD also inhibited CYP1A1 induction. Again, suggesting a role for PKC in CYP1A1 induction. Together, these results indicate that relative lymphocyte maturation state and the PKC pathway are important factors in regulating the expression of CYP1A1.

Effect of dopamine on immune cell proliferation in mice

Dopamine is known as a precursor of catecholamine and one of the neurotransmitters in brain and peripheral tissues. Recent studies suggest an important role of dopamine in immune responses. In the present study, intraperitoneal administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) which lowered endogenous dopamine suppressed splenocyte proliferation in response to mitogens such as lipopolysaccharide (LPS) and concanavalin A (Con A). Moreover, intravenous injection of the specific agonists of dopamine DA-1 receptor (SKF38393) or DA-2 receptor (LY171555) into mice enhanced the splenocyte proliferation stimulated by LPS or Con A. In the in vitro cultures, dopamine, SKF38393 and LY171555 directly promoted cell proliferation to LPS or Con A. These results indicate that dopamine has an ability to regulate B- and T-cell proliferation both in vivo and in vitro.

T-2 toxin-induced apoptosis in lymphoid organs of mice

Lymphoid organs of male and female mice of 4 strains (ICR: CD-1, BALB/c, C57BL/6 and DBA/2) were histologically and biochemically examined at 24 hours after oral inoculation of T-2 toxin (0, 2.5, 5 and 10 mg/kg b.w.). Light microscopically, dose-dependent decrease in number of lymphocytes was observed in the thymic cortex and splenic follicles. The nuclei of lymphocytes showed pyknosis or karyorrhexis, and they were positively stained by the modified TUNEL method which detects fragmented DNA in situ. Electron microscopic characteristics of damaged lymphocytes were shrinkage of the cell body, nuclear chromatin condensation and fragmentation. Agarose gel electrophoresis of DNA extracted from the thymus showed DNA fragmentation into nucleosome units, i.e. ladder formation. The above-mentioned findings clearly showed that T-2 toxin could induce apoptotic cell death in the lymphoid organs of mice. These changes were more prominent in female BALB/c and C57BL/6 mice.

Toxicity of cordycepin in combination with the adenosine deaminase inhibitor 2'-deoxycoformycin in beagle dogs

For 3 consecutive days, the nucleoside cordycepin (3'-deoxyadenosine) was administered as 1-hr iv infusions (0, 1, 4, 8, 10, or 20 mg/kg/day) to dogs. These doses were given 1 hr after a bolus iv injection (0.25 mg/kg/day) of 2'-deoxycoformycin (dCF), a potent inhibitor of adenosine deaminase. The hypothesis was that dCF would affect the toxicity of cordycepin. Plasma adenosine deaminase activity was strongly inhibited during the dose period and for 5 days following the final dose of dCF. Dogs given cordycepin alone showed no drug-related toxicities. In dogs given only dCF, drug-related toxicity to lymphoid tissue (lymphopenia and thymus lymphoid depletion), thrombocytopenia, and decreases in food consumption were observed. Cordycepin in combination with dCF produced symptoms associated with severe gastrointestinal toxicity (decreased body weights, emesis, diarrhea, decreased food consumption, and necrosis of the gastrointestinal tract) and bone marrow toxicity (lymphopenia, thrombocytopenia, and depletion of hematopoietic cells). The gastrointestinal tract and bone marrow were sites associated with dose-limiting toxicities. In surviving dogs, most of the effects were reversible by Day 30. The maximum tolerated dose of cordycepin administered in combination with dCF was 8 mg/kg/day (160 mg/m2/day) given daily for 3 days.

Lectin of Bacillus subtilis sp. as overinducer of gamma-interferonogenesis

It has been demonstrated experimentally that lectin of Bacillus subtilis sp. in comparison with generally accepted Con A, PHA and lectin of "gold rain" grass--Laburnum anagyroides M e d i k in trials on white mice of CBA line gave in 4 hours of induction maximal titers of gamma-IFN in blood serum of animals--153.6 +/- 17.0 IU/ml. Practically identical titers had been obtained after induction by lectin "gold rain", some lower--after Con A and PHA. At swine gamma-IFN synthesis optimal density of cell suspension must contain 2.5 + 10(7) immunocytes in 1 ml, owing to which it is possible to obtain the titer equal 1 : 2150. Materials with using of bacterial lectins at various degree of purification had shown that maximal titers in blood serum of mongrel white mice were registered at administration to animals of non-purified lectin, 4 times lower--at using of half-purified and purified lectins. Data of these trials in vivo were confirmed by materials of gamma-IFN induction by immunocytes of swine, cattle and even man.

Modulation of gamma glutamyl transpeptidase activity in lymphoid system by organochlorine pesticides in rats

Effects of 1,1,1,-trichloro-2,2-bis (p-chlorophenyl) ethane (DDT) and lindane were studied on gamma glutamyl transpeptidase (GGT) activity in different tissues of the lymphoid system in rats. DDT (100 or 200 ppm) and lindane (30 or 80 ppm) exposure for 8 weeks suppressed the GGT activity in a dose dependent manner in thymus and macrophage. In spleen, significant decrease in the enzyme activity was observed at higher exposure (200 ppm DDT or 80 ppm lindane) levels. Lindane suppressed GGT activity at both 30 or 80 ppm dose levels, while DDT reduced the GGT activity at 200 ppm but not at 100 ppm exposure in lymphocyte. The study indicates the possibility of using GGT as an effective and consistent biochemical marker for immunotoxicity of xenobiotics and other environmental stressors.

Extensive glycosphingolipid depletion in the liver and lymphoid organs of mice treated with N-butyldeoxynojirimycin

The imino sugar N-butyldeoxynojirimycin is an inhibitor of the ceramide-specific glucosyltransferase that catalyzes the first step in glycosphingolipid biosynthesis. It results in extensive glycosphingolipid depletion in cells treated in vitro, without causing toxicity. However, we currently do not know the degree to which glycosphingolipids can be depleted in vivo in a mammalian species. We have therefore administered N-butyldeoxynojirimycin long term to young mice and have found that glycosphingolipid levels are reduced (50-70%) in all tissues examined, without resulting in any overt pathology. When the lymphoid tissues from these mice were examined, they were found to be 50% acellular relative to non-lymphoid tissues. These data implicate a role for glycosphingolipids in the biology of the immune system or indicate an additional as yet unknown activity of N-butyldeoxynojirimycin. Extensive glycosphingolipid depletion resulting from N-butyldeoxynojirimycin administration is therefore well tolerated in adult mice, and this compound may be in an invaluable tool for probing glycosphingolipid functions in vivo. In addition, this drug may be effective in clinical situations where glycosphingolipid depletion would be desirable, such as the in the treatment of the human glycosphingolipidoses.

Induced termination of pregnancy by purified extracts of Azadirachta Indica (Neem): mechanisms involved

PROBLEM

To develop a self-administered, orally delivered method for abrogation of early pregnancy.

METHOD

Use of purified Neem extracts containing immunomodulators stimulating Th1 cells and macrophages; test animals, rats, baboons, and monkeys, onset of pregnancy confirmed by surgery and counting of implants on day 7 in rats and by chorionic gonadotropin (CG) and progesterone assays in primates; termination defined by complete resorption on day 15 in rats and by bleeding and decline of CG and progesterone in baboons.

RESULTS

Pregnancy was terminated successfully in both rodents and primates with no significant side effects. Fertility was regained in both species after one or two irregular cycles. Progeny born had normal developmental landmarks and mothered normal litters in the course of time. The active principle in Neem has been partially fractionated by activity-guided purification. A cascade of events are involved in abrogation of pregnancy. In primates, a decrease in progesterone is an early event. A transient increase in CD4 and CD8 cells is noted in spleen at 96 hr and in mostly CD8 cells in mesenteric lymph nodes. Treatment causes an elevation of both immunoreactive and bioactive TNF-alpha and gamma-interferon in serum, mesenteric lymph nodes, and foetoplacental tissue.

CONCLUSION

Immunomodulators of plant origin are potentially usable for termination of unwanted pregnancy

Effects of repeated injections of palytoxin on lymphoid tissues in mice

Sublethal doses of palytoxin were i.p. injected repeatedly to mice, and the effects on lymphoid tissues were examined. The weight and morphology of the thymus were influenced during exposure but had generally recovered after 1 month of withdrawal. The ratio of lymphocytes to total leukocytes in blood was decreased during the injection term, and did not recover to a normal level even after 1 month of withdrawal. The component of B-cells in the lymphocytes was clarified as being responsible for the small number of lymphocytes in the recovery process.

Postnatal development of B lymphocytes and immunoglobulin-containing plasma cells in the chicken oviduct: studies on cellular distribution and influence of sex hormones

Postnatal development of B lymphocytes and plasma cells containing different classes of immunoglobulins (IgG, IgA, and IgM) was immunohistochemically studied in the oviduct of the Dekalb strain of the White Leghorn chicken. B lymphocytes first appeared in the lamina propria of the chicken oviduct at 5 weeks of age. Their frequency of occurrence peaked at 15 weeks from the infundibulum to the uterus (glandular part), while in the vagina (aglandular part) it did so at 21 weeks. Intraepithelial B lymphocytes were very rare and exclusively located in the vagina at 19 and 21 weeks. Plasma cells first appeared in the lamina propria of the oviduct at 11 weeks of age, and this frequency peaked at 32 weeks. IgG-containing plasma cells were most numerous in the glandular part, whereas in the aglandular part IgA and IgM cells were more numerous than IgG cells. When 7-day-old-chickens were treated with sex hormones, B lymphocytes and plasma cells appeared 12 h and 5 days after the hormone injection, respectively. Their frequency of occurrence was statistically higher in diethylstibestrol (DES)-treated chickens than in DES plus progesterone-treated chickens. This suggests that the postnatal development of B lymphocytes and plasma cells in the oviduct of the chicken is correlated to estrogen secretion.

Suppression of in vivo IgE and tissue IL-4 mRNA induction by SDZ 280.636, a synthetic muramyl dipeptide derivative

Modulation of IgE isotype expression on B cells is one of the numerous effects of muramyl peptides on the regulation of the immune system. A non toxic diacyl glycerol derivative of muramyl dipeptide (MDP), in which the L-alanine is replaced by L-threonine (MDP-Threo-GDP; SDZ 280.636), is currently under investigation as lead compound for the development of an anti-allergic drug. In this report, the modulatory effect of orally administered SDZ 280.636 in a murine model on polyclonally induced IgE levels is described. In this model, mice are injected i.v. with goal anti mouse IgD (GAMD) and challenged three to four weeks later with goal IgG (GIG). Both the primary and secondary immune responses lead to an increase of serum IgE levels. We demonstrate the efficacy of this muramyl dipeptide derivative in selectively inhibiting a polyclonal IgE response in GAMD-primed, GIG challenged mice without affecting the levels of other immunoglobulin classes. It is further shown that the induction of interleukin 4 (IL-4) gene transcript levels in lymphoid organs, which is observed as a consequence of boosting GAMD pretreated mice with GIG, is selectively suppressed in gut associated lymphoid tissues (GALT) and mesenteric lymph nodes but not in spleen. In contrast, interleukin 13 (IL-13) mRNA levels are not affected by SDZ 280.636. The findings that SDZ 280.636 inhibits polyclonal IgE responses and suppresses IL-4, but not IL-13 mRNA expression point towards differences in the regulatory pathways of IL-4 and IL-13 gene transcription in lymphoid organs. Thus the mechanism of action appears to involve a specific suppression of IL-4 gene transcription in cells occurring in Peyer's patches and mesenteric lymph nodes which are among the first constituents of the immune system encountered by an orally administered drug.

Macrophage differentiation and expression of macrophage colony-stimulating factor in murine milky spots and omentum after macrophage elimination

To elucidate the differentiation mechanisms of macrophages in the murine omentum, we studied the repopulation of these cells and the expression of macrophage colony-stimulating factor (M-CSF) in the milky spots and omental tissues in mice depleted of macrophages following administration of liposome-encapsulated dichloromethylene diphosphonate (clodronate). The macrophages in the omentum were spindle or dendritic in shape, expressed several macrophage-specific antigens and Ia antigen, and phagocytized intraperitoneally injected carbon particles. In the milky spots, macrophages and macrophage precursors were detected, and the number of precursors increased after elimination of macrophages by intraperitoneal injection of liposome-encapsulated clodronate. Macrophage precursors in the milky spots proliferated, moved to the omentum, and transformed into dendritic-shaped macrophages. Expression of M-CSF mRNA extracted from the milky spots was markedly enhanced at 2 and 3 days after macrophage depletion. Localization of M-CSF protein and mRNA was observed in the stromal cells of the milky spots. In osteopetrosis (op/op) mutant mice that are defective in the production of functional M-CSF omental macrophages were absent. These results indicate that M-CSF locally produced in the milky spots plays an important role in providing a microenvironment for development and differentiation of omental macrophages.

Stimulating effect of an oral polybacterial immunomodulator on the proliferative activity of guinea pig lymphocytes

A preparation for the prophylaxis and treatment of inflammations of oral mucosa and parodont Dentavax (D) was investigated in guinea pigs. Animals were given orally D for 5 consecutive days and a month later the procedure was repeated. On day 3, 10, 21, and 28 after immunization and reimmunization lymphoproliferative responses to PHA, rIL-2, LPS and D were measured by the radiometric blast transformation assay in peripheral blood, spleen, mesenteric lymph nodes (MLN) and Peyer's patches (PP). The percentage of cells entering S and G2/M-phases of cell cycle was assessed by the flow cytometric DNA analysis. A correlation in proliferative activity of cells after in vitro stimulation with PHA and LPS has been established by both methods. Peak values of lymphocyte stimulation were found on day 10, especially after the second administration of D in all organs tested, mainly in MLNs and spleen. Electron-microscopic studies demonstrated an extensive development of the endoplasmatic reticulum in plasmatic cells from spleen, PPs, mesenteric, bronchial and inguinal lymph nodes. The results obtained may be considered a proof of the immunostimulating effect of Dentavax.

Process of the development of T-2 toxin-induced apoptosis in the lymphoid organs of mice

Female ICR:CD-1 mice orally treated with 10 mg/kg b.w. of T-2 toxin were killed at 1, 3, 6, 9, 12, 24 and 48 hr after treatment (HAT) and subjected to examination of the process of the development of T-2 toxin-induced apoptosis in the thymus and spleen. The early ultrastructural changes in lymphocytes characterized by shrinkage of the cell body and condensation of nuclear chromatin were detected at 3HAT in the thymus. The number of apoptotic lymphocytes observed by the in situ detection method for fragmented DNA increased drastically from 9 to 24 HAT in the thymus while it began to increase at 12 HAT in the spleen. The DNA ladder was first detected by agarose gel electrophoresis at 9 HAT and became clearer at 12 and 24 HAT in the thymus but was not clearly detected in the spleen throughout the observation period. Thus T-2 toxin-induced apoptosis developed earlier and was apparently severer in the thymus than in the spleen. Apoptotic was first detected by electron microscopy, then by the in situ detection method for fragmented DNA, and finally by DNA agarose gel electrophoresis.

Effects of stress on gamma glutamyl transpeptidase (GGT) activity in lymphoid system of rats: modulation by drugs

Effects of stress and its modulation by adaptogens were evaluated on gamma glutamyl transpeptidase (GGT) activity in different tissues of the lymphoid system in rats. Restrain stress (RSx5) suppressed the GGT activity in different tissues of lymphoid system viz. the lymphocyte, the spleen, the thymus and the macrophage, and the maximum effect was seen in the spleen. Chlordiazepoxide, a prototype anti-stress agent, which did not alter GGT activity per se, reversed the effect of RS on this enzyme activity in tissues of lymphoid system studied. Azardirachta indica (Al, Neem), an indigenous adaptogen stimulated the GGT activity per se and nearly normalised RS induced suppression of GGT in lymphoid system. The observed suppression of GGT activity in lymphoid system by stress and its modulation by natural and synthetic adaptogens indicates that GGT could be a consistent cellular/biochemical marker of stress responsiveness and stress-induced immunomodulation.

Immunotoxicological assessment of cyclosporin A by conventional pathological techniques and immune function testing in the rat

1. Groups of male rats were given different doses of cyclosporin A, ranging from the maximum tolerated dose (20 mg/kg/day) downwards, 7 days a week for 28 days using a protocol derived from OECD test guideline 407. 2. At the end of the test, one set of animals underwent a detailed necropsy and histopathological examination of lymphoid tissues. Immune function was assessed using the lymphoproliferative response and natural killer cell activity of their spleen cells. Another set of animals was immunised with sheep erythrocytes on day 25 and used to evaluate the ability to produce specific anti-sheep red blood cell antibody. 3. Cyclosporin A produced detectable effects on the immune system at all doses and at doses lower than other toxic effects. Both histopathological techniques and one of the immune function tests were able to identify changes at the lowest dose, 1.25 mg/kg/day. 4. The results of this investigation suggest that conventional histopathological techniques, if applied to a range of lymphoid organs, are sufficient to identify potential immunotoxicants without recourse to immune function tests.

Immune system alteration in the rat after indirect exposure to methyl mercury chloride or methyl mercury sulfide

Methyl mercury is a well-recognized health hazard. It is an environmental contaminant that accumulates in the food chain. The primary source of mercury exposure for humans is through the consumption of contaminated fish. We studied the effects of indirect methyl mercury exposure on the immune system of Sprague-Dawley rats. The effects of different forms of methyl mercury on immune system development were studied in Sprague-Dawley rats at 6 and 12 weeks of age. Rats were indirectly exposed to mercury during gestation and during nursing by exposing pregnant rats to either 5 or 500 micrograms/liter of methyl mercury chloride (CH3HgCl) or 5 micrograms/liter of methyl mercury sulfide [(CH3Hg)2S] in their drinking water. Total body, splenic, and thymic weights were measured, and NK cell cytolytic activity and lymphoproliferative response to T and B cell mitogens were evaluated in the offspring. At 6 weeks of age, total body and splenic weights were significantly increased in both high- and low-dose methyl mercury chloride-exposed groups. Rats exposed to methyl mercury sulfide had a significant increase in thymic weight at 6 weeks of age. At 12 weeks, the total body and organ weights were not different from controls. The lymphocyte proliferative response of splenocytes to PWM was enhanced at 6 weeks in both CH3HgCl exposed groups and not affected in the (CH3Hg)2S exposed group. NK cell activity was not affected in either group at 6 weeks of age. At age 12 weeks, NK cell activity was statistically significantly decreased by 56.6% in both CH3HgCl-exposed groups and not affected in the (CH3Hg)2S-exposed rats. The lymphocyte proliferative response of splenocytes to the B cell mitogen pokeweed remained increased in the CH3HgCl groups. Indirect exposure of rats (during gestation and nursing) to different forms of methyl mercury reveals that chloride forms have prolonged predominantly enhancing effects on lymphoproliferative response of splenocytes, followed by significant depression of NK cell activity.

[Organ cytotoxicity of selected polycyclic aromatic hydrocarbons in mice]

The cytotoxic effects of some PAHs: DMBA, 3-MC and B(a)P on the lymphatic organs, liver and kidney of mice have been investigated. These PAHs in doses of 100 mg/kg were dissolved in 0.5 ml 20% DMSO and were given intraperitoneally in female mice Balb/c. After 7 days, organs weight, cellularity in lymphoid organs and tissue structure of liver and kidney were analyzed. The greatest effect of DMBA was observed on cellularity of spleen. 3-MC and B(a)P caused significant hepatotoxic and nephrotoxic changes. 3-MC induced focal destruction of hepatocytes and sometimes--irregular mitotic figures (c-mitosis). After B(a)P administration in liver cells were mainly observed the changes in distribution of interphase nucleolar organizer region (AgNOR). In kidney--irregular glomeruli and tubuli after 3-MC and B(a)P were noted. The above results may indicate that the cytotoxic effects of PAHs depend on the type of compound administered.

Effect of sub-chronic cocaine and lidocaine exposure on the lymphoid tissues in neonatal rats

Illicit cocaine varies in purity and is often adulterated with local anesthetics such as lidocaine. Chronic cocaine exposure is associated with immunological modulation in humans and animal models. The effect of sub-chronic oral exposure to cocaine (COC) and lidocaine (LIDO) alone and in combination on the lymphoid organs was assessed in neonatal rats. Lewis rat pups were orally administered saline (SAL), COC, LIDO or both drugs in combination, 20 mg/kg each, from birth to day 21. Statistically significant (P < 0.05) decreases in lymphocyte and total leukocyte levels as well as decreases in spleen weight were observed in pups treated with COC alone. LIDO alone did not affect these parameters in comparison to SAL treated controls. Rats receiving COC and LIDO did not display a significant reduction in spleen weight or in the blood cell populations studied. However, rats treated with COC and LIDO in combination had significantly decreased serum immunoglobulin M (IgM) concentration. Quantitative plasma and tissue analyses ascertained the concentrations and tissue disposition of each drug following oral administration. The results suggest that the effect of COC on the lymphoid tissues and white blood cell parameters is modified in the presence of LIDO in the developing rat.

Castanospermine, an oligosaccharide processing inhibitor, reduces membrane expression of adhesion molecules and prolongs heart allograft survival in rats

The inhibition of intracellular oligosaccharide processing is a new approach to immunosuppression in allotransplantation. The net effect of such inhibition is reduction in the membrane expression of certain glycoproteins. Hence cell-cell interaction in allorejection may be impaired in the presence of glycoprotein processing inhibitors because the expression of key ligand-receptor pairs of N-linked glycoproteins including adhesion molecules is inhibited. The aims of this study were to measure the immunosuppressive ability of castanospermine (CAST) in a rat heart allograft model, to measure its effect on membrane expression of adhesion molecules (LFA-1 alpha, LFA-1 beta, ICAM-1), class I and class II MHC antigens and on other T cell associated molecules (CD4, CD8, CD39, CD45, W3/13), to test its tolerogenic potential and its toxicity. Membrane expression of these molecules was measured by flow cytometry for single cells and by immunoperoxidase staining for the allograft. In grafted rats CAST significantly reduced the expression of LFA-1 alpha on lymphoid cells in the thymus, lymph node, spleen and heart allografts. ICAM-1 expression on endothelial cells of the allograft vasculature, class I and class II MHC expression on lymphoid cells in the thymus, class II MHC expression on lymphoid cells in the allograft; and CD4, CD8, CD45 and W3/13 expression on lymphoid cells in some organs. By contrast, in non-grafted rats CAST significantly upregulated expression of class I MHC and CD45 in the thymus, lymph node and spleen, ICAM-1 and CD4 on lymphoid cells in the spleen, but reduced expression of LFA-1 alpha on lymphoid cells in the thymus. It also prolonged rat heart allograft survival in a dose-dependent manner and with limited testing was relatively non-toxic. In conclusion, CAST is an immunosuppressive molecule which may work by downregulation of the ligand-receptor adhesion molecule pair, LFA-1 alpha-ICAM-1 although subtle downregulation of class I and II MHC, CD4 and CD8 molecules could also contribute to its immunosuppressive activity. Hence, both lymphocyte-endothelial cell binding and lymphocyte activation may be inhibited by CAST. This work suggests that CAST may hold significant potential as a transplant immunosuppressant probably as an adjuvant agent to inhibitors of interleukin 2 secretion.

Successful bone marrow transplantation in sensitized aplastic anemia patients using total lymphoid irradiation for conditioning: long-term follow-up

Between June 1986 and November 1994, 22 previously transfused patients with severe aplastic anemia (SAA) were treated with high-dose cyclophosphamide (CY) (50 mg/kg over 4 consecutive days) and 7 Gy total lymphoid irradiation (TLI) in two fractions before allogeneic bone marrow transplantation (BMT) from HLA-identical sibling. Graft-versus-host-disease (GVHD) prophylaxis included the combination of methotrexate and cyclosporine A in all cases. Actuarial survival at 5 years is 73 +/- 9 per cent for the entire group and 86 +/- 13 per cent for the seven patients < or = 18 years. The incidence of graft failure was 0 per cent, and of acute GVHD and chronic GVHD was 31.5 per cent and 24 per cent respectively. Prolonged interval from diagnosis to BMT adversely influenced survival (P = 0.03). No hypothyroidism or secondary malignancies have been documented in this series. Our findings indicate that survival with CY-TLI is comparable to that obtained using preparative regimens without radiation. The changing role of radiotherapy in pretransplant immunosuppression for SAA is discussed.

Cytokines and their effects on maturation, differentiation and migration of dendritic cells

In this review the role of cytokines in the maturation and migration of phenotypically and functionally diverse dendritic cell (DC) subpopulations is discussed and their role in progress of differentiation from bone marrow progenitors to lymphoid DC is described. GM-CSF is the most important cytokine for the development of functional DC and acts in concert with a varying mixture of other cytokines such as IL-4, IL-1 and TNF-alpha to direct the development of individual DC subpopulations.

[A 26-week oral repeated dose toxicity study of a new antineoplastic agent S-1 in rats]

S-1 was administered to male and female rats by gavage for 26 weeks at 0, 1, 5, and 10 mg/kg/day followed by 5-week recovery period for the control, 5, and 10 mg/kg/day groups. Treatment at 5 or 10 mg/kg/day in both sexes produced keratosis of the tail, palm or sole. Weight gain and average food consumption were lowered by the treatment. Urine showed increases in protein and epithelial or white blood cells and a decrease in specific gravity. The blood showed decreases in red blood cell count, hemoglobin, and hematocrit as well as increases in MCH, platelet count, fibrinogen, and MCV. A/G ratio, albumin, and chloride were decreased while total cholesterol, free cholesterol, triglycerides, and phospholipids were increased. Histopathologically, treatment-related changes at 5 and 10 mg/kg/day were observed mainly in the lymphoid tissues and kidneys. Those changes included atrophy in the lymphoid tissues and chronic nephropathy-like changes in the kidneys. Other changes in the 10 mg/ kg/day group, included acanthosis and/or inflammation in the epidermis of the tail, sole, or palm, degeneration and disarrangement of ameloblasts, and atrophy of the testes. In a recovery study, although some changes in the sole, palm, or tail, and the kidneys remained, they were less extensive than they had been at the end of the treatment period. Based upon these observations, the non-toxic dose level was estimated to be 1 mg/kg/day (2.3 mg/kg/day, as the summed doses of tegafur, CDHP, and Oxo) in both sexes.

Local expression of transgene encoded TNF alpha in islets prevents autoimmune diabetes in nonobese diabetic (NOD) mice by preventing the development of auto-reactive islet-specific T cells

Lately, TNF alpha has been the focus of studies of autoimmunity; its role in the progression of autoimmune diabetes is, however, still unclear. To analyze the effects of TNF alpha in insulin-dependent diabetes mellitus (IDDM), we have generated nonobese diabetic (NOD) transgenic mice expressing TNF alpha under the control of the rat insulin II promoter (RIP). In transgenic mice, TNF alpha expression on the islets resulted in massive insulitis, composed of CD4+ T cells, CD8+ T cells, and B cells. Despite infiltration of considerable number of lymphoid cells in islets, expression of TNF alpha protected NOD mice from IDDM. To determine the mechanism of TNF alpha action, splenic cells from control NOD and RIP-TNF alpha mice were adoptively transferred to NOD-SCID recipients. In contrast to the induction of diabetes by splenic cells from control NOD mice, splenic cells from RIP-TNF alpha transgenic mice did not induce diabetes in NOD-SCID recipients. Diabetes was induced however, in the RIP-TNF alpha transgenic mice when CD8+ diabetogenic cloned T cells or splenic cells from diabetic NOD mice were adoptively transferred to these mice. Furthermore, expression of TNF alpha in islets also downregulated splenic cell responses to autoantigens. These data establish a mechanism of TNF alpha action and provide evidence that local expression of TNF alpha protects NOD mice from autoimmune diabetes by preventing the development of autoreactive islet-specific T cells.

Primitive cytokines and cytokine receptors in invertebrates: the sea star Asterias rubens as a model of study

It has been previously demonstrated that the sea star axial organ is a primitive immune organ. Phagocytic, lymphoid-like cells have been characterized with properties similar to those of vertebrates. There is also evidence for an invertebrate cytokine network because IL-1 and TNF-like activities are clearly demonstrable. In addition, the authors have previously described preliminary evidence for IL-2-like activity in the sea star. In the present report, the authors obtained evidence for the presence of IL-1- and IL-2-like molecules on axial organ cells. More interestingly, the results suggested that sea star cells express structures similar to human receptors for IL-1, IL-2, IL-6 and IFN-gamma.