Distribution of boron in the environment

The findings of a study to identify and quantify the orders of magnitude for major reservoirs and flows of boron (B) in the environment are outlined. The orders of magnitude for B reservoirs and flows arising through natural processes, such as the hydrological cycle and volcanism, are compared with those arising from anthropogenic activities, such as coal combustion and the extraction and use of borates for commercial purposes. The major stores and reservoirs for B have been identified, in order of magnitude, as the continental and oceanic crusts (10¹⁸ kg B), the oceans (10¹⁵ kg B), groundwater (10¹¹ kg B), ice (10¹¹ kg B), coal deposits (10¹⁰ kg B), commercial borate deposits (10¹⁰ kg B), biomass (10¹⁰ kg B), and surface waters (10⁸ kg B). The largest flows of B in the environment arise from the movement of B into the atmosphere from oceans, at between 1.3 * 10⁹ kg and 4.5 * 10⁹ kg B per annum. Other hydrological flows are also important. Drainage from soil systems into groundwaters and surface waters accounts for between 4.3 * 10⁸ kg and 1.3 * 10⁹ kg B per annum. B mining and volcanic eruptions represent the next most significant B flows, accounting for approx 4.0 * 10⁸ kg and 3.0 * 10⁸ kg B, respectively.     

Boron mobility in peanut (Arachis hypogaea L.)

In most plant families, boron (B) is phloem immobile. For plants such as peanut which bury their fruit, the mechanism for B delivery and the B source for fruit and seed growth remains enigmatic. Therefore, this study aimed to establish evidence of B retranslocation in peanut and to identify its importance in plant development. In a sand culture experiment, the increase in B contents in new organs after B withdrawal and the corresponding decline in B contents in older organs was evidence of B redistribution. In a foliar ¹⁰B experiment, the ¹⁰B abundance of treated-leaves decreased and ¹⁰B was detected in leaves and flowers formed after the application of foliar B. Application of ¹⁰B to the roots for a period also provided evidence for the retranslocation of ¹⁰B accumulated during the first growth period. The ¹⁰B abundance in older plant parts declined and ¹⁰B appeared in new organs (flowers, pegs, leaves) that had developed after the ¹⁰B supply had been replaced by ¹¹B. In the fourth experiment, foliar application of B reduced hollow heart, a symptom of B deficiency in seeds, in cv. TAG 24 from 39 to 8% and in Tainan 9 from 63 to 18%. These experiments all provide evidence for B retranslocation in peanut, but further work on the relative importance of the xylem and phloem pathways for B loading into the fruit is needed.     

2B4+ CD8+ T cells play an inhibitory role against constrained HIV epitopes

Cytotoxic T cells play a critical role in the control of HIV and the progression of infected individuals to AIDS. 2B4 (CD244) is a member of the SLAM family of receptors that regulate lymphocyte development and function. The expression of 2B4 on CD8⁺ T cells was shown to increase during AIDS disease progression. However, the functional role of 2B4⁺ CD8⁺ T cells against HIV infection is not known. Here, we have examined the functional role of 2B4⁺ CD8⁺ T cells during and after stimulation with HLA B14 or B27 restricted HIV epitopes. Interestingly, IFN-γ secretion and cytotoxic activity of 2B4⁺ CD8⁺ T cells stimulated with HIV peptides were significantly decreased when compared to influenza peptide stimulated 2B4⁺ CD8⁺ T cells. The expression of the signaling adaptor molecule SAP was downregulated in 2B4⁺ CD8⁺ T cells upon HIV peptide stimulation. These results suggest that 2B4⁺ CD8⁺ T cells play an inhibitory role against constrained HIV epitopes underlying the inability to control the virus during disease progression.     

Semisynthetic analogues of insulin. The use of N-substituted derivatives of methionine as acid-stable protecting groups

1. We describe the use of benzyloxycarbonylmethionine and ethoxycarbonylmethionine for the selective protection of the amino groups of glycine-A1 and lysine-B29 of pig insulin. We have used the Edman method to remove residues from the N-terminal and of the B-chain of the N^A1N^B29-di-protected derivatives. The benzyloxycarbonyl group shows slight but noticeable lability in the acid-cleavage step, but the ethoxycarbonyl group remained intact even after five cycles of degradation. 2. We have prepared the following truncated forms of insulin via the di(ethoxycarbonylmethionyl) derivative: des-Phe^B1-insulin;des-(Phe^B1-Val^B2)-insulin; des-(Phe^B1-Val^B2-Asn^B3)-insulin;des- (Phe^B1-Val^B2-Asn^B3-Gln^B4)-insulin; des-(Phe^B1-Val^B2-Asn^B3 -Gln^B4-His^B5)-insulin. 3. Insulin was re-synthesized from the di-protected des-Phe^B1-insulin by reaction with an active ester of t-butoxycarbonyl-l-phenylalanine. The product after deprotection crystallized, and the immunoreactivity of the crystalline material was identical with that of the native protein. 4. We have prepared the following analogues of insulin in a similar manner: [l-Ala^B1]insulin; [l-Val^B1]insulin; [l-Tyr^B1]insulin; [m-F-l-Phe^B1]insulin; [o-F-l-Phe^B1]-insulin; [o-F-l-Phe^B2]des-Phe^B1-insulin. All had between 34 and 62% of the activity of insulin in the fat-cell test. 5. We have also investigated the use of the benzyol, toluene-p-sulphonyl, p-nitrobenzyloxycarbonyl and 2,4-dinitrophenyl groups for the N-protection of the methionine active esters. Each should have had some particular advantage over the benzyloxycarbonyl and ethoxycarbonyl groups, but all proved in practice to have disadvantages that more than outweighed anything in their favour.     

Thirteen new chromosome-7 congenic lines

Thirteen new congenic lines have been produced which have chromosome-7 segments introduced from different strains onto the C57BL/10Sn background. Sublines B10.P(61NX)C,D, and E received chromosome-7 segments from P/J, B10.CE(62NX) from CE/J, B10.SEC(64NX)A,C,E, and F from SEC/1Re, B10.SM(65NX) from SM/J, B10.WB(66NX) from WB/Re, B10.A(67NX) from A/SnGrf, B10.AKR(68NX) from AKR/SnGrf, and B10.K(69NX) from C3H.K. Isograft testing indicated that three sublines, B10.P(61NX)D, B10.CE(62NX)B, and B10.WB(66NX)B are histoisogenic, i.e., histocompatible within each line. With the exception of B10.A(67NX), B10.AK(68NX), and B10.K(69NX), which have not been isografted, the remaining sublines showed residual heterozygosity on isografting. The three histoisogenic lines have undergone F₁ testing and have been found to possess theH-4 ^a allele and new and distinct alleles at theH-1 locus. They have been designated B10.P(61NX)-H-4^a H-1 ^d , B10.WB(66NX)-H-4^a H-1 ^e , and B10.CE(62NX)-H-4^a H-1 ^f . Direct exchange of grafts has indicated the following genotypes: B10.A(67NX)-H-4^a H-1 ^b , B10.AK(68NX)-H-4^a H-1 ^b , and B10.K(69NX)-F-4^a H-1 ^b . The B10.SEC(64NX) and B10.SM(65NX) sublines have not been typed completely forH-4 andH-1. F ₁ testing or direct exchange of skin grafts indicated that B10.P(61NX)-H-4^a H-1 ^d , B10.WB(66NX)-H-4^a H-1 ^e , B10.A(67NX)-H-4^a H-1 ^b B10.AK(68NX)-H-4^a H-1 ^b and B10.K(69NX)-H-4^a H1 ^b possess nonon-H-1 histocompatibility differences from the G57BL/10 background.     

Identification and characterization of autoantibody-producing B220 B (B-1) cells appearing in malarial infection

Mice with malaria showed unique immunological responses, including the expansion of NK1.1⁻TCR^int cells (extrathymic T cells). Since TCR^int cells with autoreactivity and autoantibody-producing B cells (B-1 cells) are often simultaneously activated under autoimmune conditions, it was examined whether B-1 cells were activated in the course of malarial infection. From days 14 after infection, B220^low B-1 cells appeared in the liver and spleen. The number of B220^low B cells was highest at day 14, but the ratio was highest at days 28-35. In parallel with the appearance of B220^low cells, autoantibodies against HEp-2 cells and double-stranded DNA were detected in sera. These B220^low cells had phenotypes of CD44^high, CD23⁻ and CD62L⁻. In sharp contrast, conventional B220^high B cells (B-2 cells) were CD44^low, CD23⁺ and CD62L⁺. These results suggested that malaria immune responses were not mediated by conventional T and B cells but resembled the responses during autoimmune diseases.     

Separation of Plasmacytoid Dendritic Cells from B-Cell-Biased Lymphoid Progenitor (BLP) and Pre-Pro B Cells Using PDCA-1

B-cell-biased lymphoid progenitors (BLPs) and Pre-pro B cells lie at a critical juncture between B cell specification and commitment. However, both of these populations are heterogenous, which hampers investigation into the molecular changes that occur as lymphoid progenitors commit to the B cell lineage. Here, we demonstrate that there are PDCA-1⁺Siglec H⁺ plasmacytoid dendritic cells (pDCs) that co-purify with BLPs and Pre-pro B cells, which express little or no CD11c or Ly6C. Removal of PDCA-1⁺ pDCs separates B cell progenitors that express high levels of a Rag1-GFP reporter from Rag1-GFP^low/neg pDCs within the BLP and Pre-pro B populations. Analysis of Flt3-ligand knockout and IL-7Rα knockout mice revealed that there is a block in B cell development at the all-lymphoid progenitor (ALP) stage, as the majority of cells within the BLP or Pre-pro B gates were PDCA-1⁺ pDCs. Thus, removal of PDCA-1⁺ pDCs is critical for analysis of BLP and Pre-pro B cell populations. Analysis of B cell potential within the B220⁺CD19⁻ fraction demonstrated that AA4.1⁺Ly6D⁺PDCA-1⁻ Pre-pro B cells gave rise to CD19⁺ B cells at high frequency, while PDCA-1⁺ pDCs in this fraction did not. Interestingly, the presence of PDCA-1⁺ pDCs within CLPs may help to explain the conflicting results regarding the origin of these cells.     

Semisynthesis and properties of some insulin analogs

The trypsin-catalyzed coupling of bovine (Boc)₂-desoctapeptide (B23-B30)-insulin with synthetic octapeptides, H-Gly-X₂-X₃-X₄-Thr-Pro-Lys(Boc)-Thr-OH (X₂ = Phe or Ala, X₃ = Phe or Ala, X₄ = Tyr or Ala), followed by deprotection and purification produced the [Ala^B24, Thr^B30]-, [Ala^B25, Thr^B30]-, and [Ala^B26, Thr^B30]-analogs of bovine insulin in yields of 32, 35, and 32%, respectively. The biological activity of these analogs decreased in the order, normal insulin ([Thr^B30]-bovine insulin) = Ala^B26-insulin > Ala^B25-insulin > Ala^B24-insulin, as assayed for receptor binding and some other biological effects, in contrast with the corresponding Leu-analogs of human insulin, in which the activity decreased in the order, normal insulin > Leu^B24-insulin > Leu^B25-insulin. The affinity to insulin antibodies greatly diminished in both Ala^B24-insulin and Leu^B24-insulin but not in the B25-substituted analogs. The CD spectra of the Leu- and the Ala-analogs were compared with those of normal insulins to show that no apparent correlation seems to exist between the decrease in biological activity and the conformational changes observed in solution. The effects of organic solvents on the peptide-bond equilibrium and on the stability of trypsin are also discussed.     

Absorption and mobility of foliar-applied boron in soybean as affected by plant boron status and application as a polyol complex

In the present study (i) the impact of plant Boron (B) status on foliar B absorption and (ii) the effect of B complexation with polyols (sorbitol or mannitol) on B absorption and translocation was investigated. Soybean (Glycine max (L.) Meer.) plants grown in nutrient solution containing 0 ??M, 10 ??M, 30 ??M or 100 ??M ¹¹B labelled boric acid (BA) were treated with 50 mM ¹⁰B labelled BA applied to the basal parts of two leaflets of one leaf, either pure or in combination with 500 mM sorbitol or mannitol. After one week, ¹⁰B concentrations in different plant parts were determined. In B deficient leaves (0 ??M ¹¹B), ¹⁰B absorption was significantly lower than in all other treatments (9.7% of the applied dose vs. 26%?C32%). The application of BA in combination with polyols increased absorption by 18?C25% as compared to pure BA. The absolute amount of applied ¹⁰B moving out of the application zone was lowest in plants with 0 ??M ¹¹B supply (1.1% of the applied dose) and highest in those grown in 100 ??M ¹¹B (2.8%). The presence of sorbitol significantly decreased the share of mobile ¹⁰B in relation to the amount absorbed. The results suggest that ¹¹B deficiency reduces the permeability of the leaf surface for BA. The addition of polyols may increase ¹⁰B absorption, but did not improve ¹⁰B distribution within the plant, which was even hindered when applied a sorbitol complex.     

Control of the antibody response of C57BL/6 Lyt-congenic strains to the Lyt-3.1 alloantigen by a gene linked to theLyt-2 locus

Congenic anti-Lyt-3.1 sera have recently been produced by immunizing B6-Lyt-2^a mice with thymocytes from either B6-Lyt-2^a, Lyt-3^a or B6-Lyt-2^a, Lyt-3^a, H-2^k mice (Boos et al. 1978). Surprisingly, mice of the congenic strain B6 failed to produce either anti-Lyt-2.1 or anti-Lyt-3.1 cytotoxic antibodies after identical immunizations. To determine the genetic basis for the difference in response to Lyt-3.1, (B6 × B6-Lyt-2^a)F_a mice and progeny of the backcross, (B6 × B6-Lyt-2^a)F₁ × B6-Lyt-2^a, were immunized with B6-Lyt-2^a, Lyt-3^a, H-2^k thymocytes. In addition, thymic biopsies of backcross progeny were performed and thymocytes tested for the Lyt-2.2 antigenic specificity. Results indicate that gene(s) governing the immune response to Lyt-3.1 is (are) linked to theLyt-2 locus, and that the responder allele (linked toLyt-2 ^a ) shows very poor penetrance in Lyt-2^a/Lyt-2^b mice.     

Immunological properties of Fc receptor on lymphocytes. 5. Suppressive regulation of humoral immune response by Fc receptor bearing B lymphocytes.

High anti-DNP PFC responses to DNP-DE or DNP-KLH were obtained by transferring normal or primed FcR^? B cell fractions into irradiated syngeneic recipients. On the other hand, the FcR⁺ B cell fraction showed a low precursor activity. Trypsinization of the FcR⁺ B cells, to eliminate remaining antigen-antibody complexes on the surface, failed to augment the response in comparison with that of trypsin-untreated FcR⁺ B cells. Therefore, the weak precursor activity of FcR⁺ B cells seemed to be inherent. No synergistic interaction between the FcR⁺ B and precursor FcR^? B cells, to give rise to the maximum PFC response, was observed. On the contrary, the FcR⁺ B cells significantly suppressed the PFC responses of FcR^? B cells. This kind of suppression could be mediated by a factor released from the FcR⁺ B cell, but not from the FcR^? B or original-unrosetted spleen cell fraction. The factor was not attributable to macrophages, because the FcR⁺ B cells isolated from normal spleen cells, of which macrophages were depleted by Sephadex G-10 columns, could produce the factor with the same activity. Stimulation by specific antigen is not necessary for the induction of the factor(s) as well as of the suppressing FcR⁺ B cells. It seems to be necessary to stimulate FcR by antigen-antibody complexes to produce or release this factor.     

Differential Effects of Tacrolimus versus Sirolimus on the Proliferation,Activation and Differentiation of Human B Cells

The direct effect of immunosuppressive drugs calcineurin inhibitor (Tacrolimus, TAC) and mTOR inhibitor (Sirolimus, SRL) on B cell activation, differentiation and proliferation is not well documented. Purified human B cells from healthy volunteers were stimulated through the B Cell Receptor with Anti-IgM + anti-CD40 + IL21 in the absence / presence of TAC or SRL. A variety of parameters of B cell activity including activation, differentiation, cytokine productions and proliferation were monitored by flow cytometry. SRL at clinically relevant concentrations (6 ng/ml) profoundly inhibited CD19⁺ B cell proliferation compared to controls whereas TAC at similar concentrations had a minimal effect. CD27⁺ memory B cells were affected more by SRL than naïve CD27^- B cells. SRL effectively blocked B cell differentiation into plasma cells (CD19⁺CD138⁺ and Blimp1⁺/Pax5^low cells) even at low dose (2 ng/ml), and totally eliminated them at 6 ng/ml. SRL decreased absolute B cell counts, but the residual responding cells acquired an activated phenotype (CD25⁺/CD69⁺) and increased the expression of HLA-DR. SRL-treated stimulated B cells on a per cell basis were able to enhance the proliferation of allogeneic CD4⁺CD25⁻ T cells and induce a shift toward the Th1 phenotype. Thus, SRL and TAC have different effects on B lymphocytes. These data may provide insights into the clinical use of these two agents in recipients of solid organ transplants.     

Decreased Frequency of Intestinal Regulatory CD5+ B Cells in Colonic Inflammation

Background

CD5⁺ B cells are a type of regulatory immune cells, though the involvement of this B cell subset in intestinal inflammation and immune regulation is not fully understood.

Methods

We examined the distribution of CD5⁺ B cells in various mouse organs. Expression levels of CD11b, IgM, and toll-like receptor (TLR)-4 and -9 in B cells were evaluated. In vitro, TLR-stimulated IL-10 production by colonic lamina propria (LP) CD5⁺ and CD5^- B cells was measured. In vivo, mice with acute or chronic dextran sulfate sodium (DSS)-induced colonic injury were examined, and the frequency of colonic LP CD5⁺ B cells in those was assessed by flow cytometry.

Results

The expression level of TLR9 was higher in colonic LP CD5⁺ B cells as compared to CD5^- B cells. Colonic LP CD5⁺ B cells produced greater amounts of IL-10 following stimulation with TLR ligands, especially TLR9, as compared with the LP CD5^- B cells. Acute intestinal inflammation transiently decreased the frequency of colonic LP CD5⁺ B cells, while chronic inflammation induced a persistent decrease in colonic LP CD5⁺ B cells and led to a CD5^- B cell-dominant condition.

Conclusion

A persistent altered mucosal B cell population caused by chronic gut inflammation may be involved in the pathogenesis of inflammatory bowel diseases.     

Supernormal insulin: [D-PheB24]-insulin with increased affinity for insulin receptors

[D-Phe^B24]- and [D-Phe^B25]-human insulin were semisynthesized from porcine insulin by enzyme assisted coupling method. Receptor binding ability of [D-Phe^B24]- and [D-Phe^B25]-insulin was 180% and 4%, respectively, of that of human insulin. Increased affinity of [D-Phe^B24]-insulin was ascribed to markedly decreased dissociation rate in binding to human cultured lymphocytes. Negative cooperative effect of [D-Phe^B24]insulin was also increased to twice of that of human insulin. Biological activity of these analogues was assessed by 2-deoxy-glucose uptake studies in isolated adipocytes and the ability of [D-Phe^B24]- and [D-Phe^B25]-insulin was 140% and 4%, respectively, of that of human insulin. These findings suggest that B25 L-Phe is more crucial for receptor binding and that [D-Phe^B24]-insulin is the first semisynthetic insulin to show increased affinity for insulin receptors.     

Divalent metal ion complexes of S100B in the absence and presence of pentamidine

As part of an effort to inhibit S100B, structures of pentamidine (Pnt) bound to Ca²⁺-loaded and Zn²⁺,Ca²⁺-loaded S100B were determined by X-ray crystallography at 2.15 Å (R_free = 0.266) and 1.85 Å (R_free = 0.243) resolution, respectively. These data were compared to X-ray structures solved in the absence of Pnt, including Ca²⁺-loaded S100B and Zn²⁺,Ca²⁺-loaded S100B determined here (1.88 Å; R_free = 0.267). In the presence and absence of Zn²⁺, electron density corresponding to two Pnt molecules per S100B subunit was mapped for both drug-bound structures. One Pnt binding site (site 1) was adjacent to a p53 peptide binding site on S100B (± Zn²⁺), and the second Pnt molecule was mapped to the dimer interface (site 2; ± Zn²⁺) and in a pocket near residues that define the Zn²⁺ binding site on S100B. In addition, a conformational change in S100B was observed upon the addition of Zn²⁺ to Ca²⁺-S100B, which changed the conformation and orientation of Pnt bound to sites 1 and 2 of Pnt-Zn²⁺,Ca²⁺-S100B when compared to Pnt-Ca²⁺-S100B. That Pnt can adapt to this Zn²⁺-dependent conformational change was unexpected and provides a new mode for S100B inhibition by this drug. These data will be useful for developing novel inhibitors of both Ca²⁺- and Ca²⁺,Zn²⁺-bound S100B.     

A Highlights from MBoC Selection: Reciprocal knock-in mice to investigate the functional redundancy of lamin B1 and lamin B2

Lamins B1 and B2 (B-type lamins) have very similar sequences and are expressed ubiquitously. In addition, both Lmnb1- and Lmnb2-deficient mice die soon after birth with neuronal layering abnormalities in the cerebral cortex, a consequence of defective neuronal migration. The similarities in amino acid sequences, expression patterns, and knockout phenotypes raise the question of whether the two proteins have redundant functions. To investigate this topic, we generated “reciprocal knock-in mice”—mice that make lamin B2 from the Lmnb1 locus (Lmnb1^B2/B2) and mice that make lamin B1 from the Lmnb2 locus (Lmnb2^B1/B1). Lmnb1^B2/B2 mice produced increased amounts of lamin B2 but no lamin B1; they died soon after birth with neuronal layering abnormalities in the cerebral cortex. However, the defects in Lmnb1^B2/B2 mice were less severe than those in Lmnb1-knockout mice, indicating that increased amounts of lamin B2 partially ameliorate the abnormalities associated with lamin B1 deficiency. Similarly, increased amounts of lamin B1 in Lmnb2^B1/B1 mice did not prevent the neurodevelopmental defects elicited by lamin B2 deficiency. We conclude that lamins B1 and B2 have unique roles in the developing brain and that increased production of one B-type lamin does not fully complement loss of the other.     

Translocation and effectiveness of foliar-fertilized boron in broccoli plants of varying boron status

The translocation and effectiveness of foliar-fertiilized boron (B) was investigated in broccoli plants supplied via the root system with luxury, sufficient or deficient levels of B. ¹⁰B-enriched boric acid was applied three times to lower leaves, beginning one week prior to inflorescence emergence, and the shoot and floret yields, as well as the ¹⁰B and ¹¹B contents or concentrations of xylem sap, phloem exudate and various plant parts, were determined three weeks after inflorescence emergence. The amount of ¹⁰B translocated in phloem from fed leaves to the remainder of the shoot did not exceed 0.5%, of that supplied, but it was inversely related to plant-B status. The partitioning of translocated ¹⁰B to florets (16–30%) and the degree of enhancement in floret yield (28–75%) was also inversely related to plant-B status. It is concluded that foliar-B fertilization may be more effective for preventing B deficiency than soil-derived B in leaves.Abbreviations ¹⁰B/¹¹B mass isotopes of boron - DM dry matter - FF foliar fertilization - RF root fertilization     

Interactions of erythrosin B (U.S. F,D & C Red 3) with rat cortical membranes

Erythrosin B inhibits Na, K-ATPase in rat brain tissue as demonstrated by studying glycoside binding, ATPase activity and ion fluxes. The potency of the noncompetitive inhibition of [³H]-ouabain binding by erythrosin B is influenced by glycoside concentration, monovalent cation concentration, and incubation time. [¹⁴C]- Erythrosin B binds to synaptic membranes prepared from rat cortex. Erythrosin B and some of its structural analogs inhibit both [³H]-ouabain and [¹⁴C]-erythrosin B binding, but ouabain and other glycosides do not inhibit the binding of [¹⁴C]-erythrosin B. Subcellular distributions of [³H]-ouabain and [¹⁴C]- erythrosin B binding in fractionated cortical tissue preparations are equivalent and parallel ATPase activity. The dissimilar response of [³H]-ouabain binding and [¹⁴C]-erythrosin B binding to changes in tissue preparation, incubation temperature, and partial solubilization of binding sites by deoxycholate (DOC) Suggests two separate binding sites for erythrosin and ouabain to rat cortical membranes.     

Participation of NK1.1+ T Cells in the Rejection of lpr αβT Cells When Bone Marrow Cells of Ipr Mice Are Transplanted into B6 Mice

When C57BL/6 (B6) mice were irradiated (9 Gy) and received bone marrow (BM) cells of B6-lpr/lpr mouse origin (i.e., lpr→B6), all mice died within 6 days. In the irradiated B6 mice, radioresistant CD3^? IL-2Rβ⁺ NK cells and IL-2Rβ CD3^int cells (i.e., CD3^int cells of extrathymic origin) remained, especially in the liver. There were two subsets, NK1.1⁺ and NK1.1^?, among the IL-2Rβ⁺ CD3^int cells. However, the NK1.1⁺ subset (i.e., NK1.1⁺ T cells) was much more radioresistant, and the majority of CD3^int cells belonged to this subset in irradiated mice. The expansion of lymphocytes from injected BM cells did not occur in the irradiated B6 mice. However, such expansion did take place in irradiated B6-lpr/lpr mice injected with both BM cells of B6-lpr/lpr and B6 origin. As a result, the mice subjected to BM cells survived. Irradiated B6 mice were treated in vivo with anti-NK1.1 mAb or anti-asialoGM₁ antibody to eliminate NK cells alone or both NK cells and NK1.1⁺ T cells. When irradiated B6 mice were pretreated with anti-NK1.1 mAb, the mice could survive. These results suggest that intact NK1.1⁺ T cells of extrathymic origin may recognize abnormal BM cells with the lpr gene and inhibit the expansion of lymphocytes, including abnormal double-negative CD4^?8^? cells, in B6-lpr/lpr mice. To inhibit the expansion of lymphocytes, mechanisms other than Fas ligand/Fas molecules on extrathymic T cells may be responsible.     

Aspirin Prevents Apoptosis and NF-κB Activation Induced by H2O2 in HeLa Cells

The classical pathway of nuclear factor-kappa B (NF-κB) activation by several inducers mainly involves the phosphorylation of IκBα by a signalsome complex composed of IκBα kinases (IKKα and IKKβ). However, in some cell types hydrogen peroxide (H²O²) has been shown to activate an alternative pathway that does not involve the classical signalsome activation process. In this study, we demonstrate that H²O² induced NF-κB activation in HeLa cells through phosphorylation and degradation of IκB proteins as shown by immunblot analysis. Our studies reveal that a commonly used non-steroid anti-inflammatory drug, acetylsalicylic acid (aspirin) prevents H²O²-induced NF-κB activation in a dose-dependent manner through inhibition of phosphorylation and degradation of IκBα and IκBβ. Differential staining and DNA fragmentation analysis also show that aspirin preloading of HeLa cells also prevents H²O²-induced apoptosis in a dose-dependent manner with maximum efficiency at 10?mM concentration. Additionally, aspirin effectively prevents caspase-3 and caspase-9 (cysteinyl aspartate-specific proteases) activation by H²O². These results suggest that NF-κB activation is involved in H²O²-induced apoptosis and aspirin may inhibit both processes simultaneously.