Tamaduni na fasihi za kienyeji kwa lugha za kigeni

Uhusiano baina ya lugha na utamaduni, mila na mirathi ya jamii kwa jumla huenda ukafahamika angalau kwa wepesi, iwapo tutazingatia mambo mawili: kwanza, lugha na matumizi yake ni chombo cha kujieleleza thamani tafauti zilizofungamana na maumbile ya kimila, fikira, maarifa, imani, adabu na utamaduni wa jamii yenyewe kwa jumla. Pili, matumizi ya lugha aghlabu husadifu kuwa ndio msingi wa kuendeleza na kukuza, na hata pia kubuni, uzushi mpya katika mirathi ya utamaduni, mila na khulka za kijamii. Kwa hivyo si rahisi kwa lugha kutengamana na taswira za jamii: utu, utamaduni, mila, mitindo na mengineo. Tungependa kuandaa madhumuni yetu ya kuonesha athari na hatari zinazokabili hali ile ya kutumia lugha geni katika kuendeleza shughuli za jamii au taifa la kienyeji. Muhimu pia, tutashughulika na athari za mtindo huo katika fasihi za kienyeji, hasa tunapozingatia kuwa fasihi ya maandishi ni mfano wa kioo cha hakika ya jamii

Tamaduni na fasihi za kienyeji kwa lugha za kigeni

Uhusiano baina ya lugha na utamaduni, mila na mirathi ya jamii kwa jumla huenda ukafahamika angalau kwa wepesi, iwapo tutazingatia mambo mawili: kwanza, lugha na matumizi yake ni chombo cha kujieleleza thamani tafauti zilizofungamana na maumbile ya kimila, fikira, maarifa, imani, adabu na utamaduni wa jamii yenyewe kwa jumla. Pili, matumizi ya lugha aghlabu husadifu kuwa ndio msingi wa kuendeleza na kukuza, na hata pia kubuni, uzushi mpya katika mirathi ya utamaduni, mila na khulka za kijamii. Kwa hivyo si rahisi kwa lugha kutengamana na taswira za jamii: utu, utamaduni, mila, mitindo na mengineo. Tungependa kuandaa madhumuni yetu ya kuonesha athari na hatari zinazokabili hali ile ya kutumia lugha geni katika kuendeleza shughuli za jamii au taifa la kienyeji. Muhimu pia, tutashughulika na athari za mtindo huo katika fasihi za kienyeji, hasa tunapozingatia kuwa fasihi ya maandishi ni mfano wa kioo cha hakika ya jamii

Tamaduni na fasihi za kienyeji kwa lugha za kigeni

Uhusiano baina ya lugha na utamaduni, mila na mirathi ya jamii kwa jumla huenda ukafahamika angalau kwa wepesi, iwapo tutazingatia mambo mawili: kwanza, lugha na matumizi yake ni chombo cha kujieleleza thamani tafauti zilizofungamana na maumbile ya kimila, fikira, maarifa, imani, adabu na utamaduni wa jamii yenyewe kwa jumla. Pili, matumizi ya lugha aghlabu husadifu kuwa ndio msingi wa kuendeleza na kukuza, na hata pia kubuni, uzushi mpya katika mirathi ya utamaduni, mila na khulka za kijamii. Kwa hivyo si rahisi kwa lugha kutengamana na taswira za jamii: utu, utamaduni, mila, mitindo na mengineo. Tungependa kuandaa madhumuni yetu ya kuonesha athari na hatari zinazokabili hali ile ya kutumia lugha geni katika kuendeleza shughuli za jamii au taifa la kienyeji. Muhimu pia, tutashughulika na athari za mtindo huo katika fasihi za kienyeji, hasa tunapozingatia kuwa fasihi ya maandishi ni mfano wa kioo cha hakika ya jamii

Administration of IL-2-Anti-IL2mAb Complex Post-Allogeneic HCT: a New Approach to Facilitate Rapid and Stable Hematopoietic Chimerism Following Reduced Intensity Conditioning and Experimental HCT

Abstract Engraftment and the induction of tolerance to donor antigens is a central aim of allogeneic hematopoietic cell transplantation (HCT). Currently, the administration of Treg cells is being examined as a new approach to support these processes. Based upon the reported ability of IL-2 anti-IL-2 mAb complex (IACX) to expand CD4+CD25+ FoxP3+ (Tregs) in vivo, we hypothesized that the administration of this complex to allogeneic HCT recipients may expand host Treg cells and inhibit host anti-donor responses, thereby effectively facilitating hematopoietic engraftment. To begin to address these questions, the effect of IACX treatment on the frequency of circulating Tregs was examined. Two days following the second injection of IACX in normal or reduced intensity conditioned (RIC) mice, the % of circulating Tregs in IACX treated mice was strikingly increased vs. PBS treated controls. Notably, the expression of Treg CD25 (MFI) was also significantly elevated (p<0.05) in IACX treated mice, consistent with the expansion and activation of Tregs following IACX treatment. Varying regimens of the complex were then administered to RIC MHC-matched allogeneic recipients. B6 mice (RIC, 5.5 Gy TBI) transplanted with 4 × 106 BALB. B TCD-BM (day 0) were administered IACX (rIL-2/JES6-1) at days −5 and −3 (pre-HCT) or days +3 and +5 (post-HCT). In multiple independent studies, IACX treatment post-HCT consistently induced markedly superior expansion of host Treg populations at 1 wk post-HCT. Analysis of donor cells (Ly9.1+) 1 wk post-HCT clearly demonstrated that recipients treated with IACX post-HCT had markedly increased levels of circulating donor cells compared to the pre-HCT and PBS treated recipients (p<0.0001). To address the hypothesis that Treg expansion and activation following IACX treatment could inhibit host anti-donor CD8 T cell reactivity, host CD8+ T cell responses to the immunodominant donor epitope (H60) were analyzed by tetramer staining during the first 3 wks post-HCT. The frequency of these cells in recipients administered IACX post-HCT was greatly reduced compared to pre-HCT and PBS treated groups. Finally, to determine the effect of IACX treatment on engraftment, long-term chimerism was examined. Analysis for donor chimerism at 25 weeks post-HCT demonstrated: that only recipients administered IACX post-HCT were chimeric, containing high levels of donor cells vs. IACX pre-HCT and PBS controls, i.e. 36.1 ± 10.9% SE, 1.2 ± 0.785 and 0.78 ± 0.18, respectively. These findings demonstrate that infusion of IL-2 anti-IL-2mAb IACX in RIC allogeneic HCT can induce stable, long-term donor hematopoietic chimerism. Notably, the timing of IACX administration was found to be crucial with respect to conditioning and hematopoietic progenitor cell transplantation. At least part of the mechanism appears to involve the suppression of host anti-donor T cell responses, which presumably facilitates the initiation of early chimerism during the process of engraftment by donor cells. This approach may provide a new strategy to promote successful hematopoietic engraftment by manipulating endogenous Treg cells and thereby obviating the need for Treg infusions in certain transplant settings

Antigen-Specific CD8+ Memory T Cells Survive, Function and Populate the Host Marrow Compartment Following Ablative TBI and Allogeneic BMT

Abstract We are interested in investigating the survival and location of host CD8 memory (TM) cells following allogeneic hematopoietic cell transplants (HCT). The H60 antigen dominates the immune response in B6 mice primed with BALB.B antigens (B6BALB.B). In such primed recipients, transplant of BALB.B MiHA-disparate marrow BM induces CD8 TM responses that mediate resistance to bone marrow engraftment. Therefore an H60 tetramer (LTFNYRNL/H2-Kb) conjugated to PE was used to detect host H60-specific CD8 TM in the spleen and marrow compartments. In the marrow compartment, the frequency of H60+ cells amongst the CD8+ T cell population was significantly (p = 90% of CD8+ H60+ cells expressed the central memory phenotype (CD44+, Ly6C+ CD25−, CD69−). To mediate resistance to progenitor cell engraftment, H60-specific effector CD8+ TM must first survive the immediate post-HCT milieu in the hemopoietic compartments. We observed a dose-dependent increase in percent of CD8+ T cells expressing the H60 TCR in the spleen as well as bone marrow in B6BALB.B mice irradiated at 3.0, 6.0 (non-ablative) and 9.0 Gy (ablative) 24 hrs post-HCT. Five days post-HCT, CD8+ H60+ cells were also readily detectable. At this time, resistance to engraftment assessed by IL-3 progenitor assay was present in sensitized, ablatively conditioned recipient mice transplanted with 5 X 106 BALB.B or congenic H60 TCD-BM. We then utilized a “double transplant” model to determine the compartmental distribution and function of MiHA-specific TM at later intervals (14 days) post-HCT. B6 mice containing CD8 TM were ablatively conditioned and 24 hrs later received syngeneic B6 (Ly 5.2) BMT. Twelve days following this syngeneic HCT, the mice were irradiated at 4.5 Gy and administered a second HCT consisting of either syngeneic (Ly 5.1) or allogeneic HCT (5 X 106 TCD-BM). These recipients were assessed for donor progenitors 10 days later. At this time point, H60+ CD8 TM were again readily detectable in both compartments, indicating that these TM effectors survived ablative (and subsequent non-ablative) conditioning and were present at this time post-transplant. Resistance to allogeneic marrow engraftment as assessed by IL-3 progenitor assay was detected after this subsequent transplant with BALB.B BM. These findings indicate that host TM survive and function following ablative conditioning and HCT. To evaluate if the viability of host CD8 TM differed in the host compartments following HCT, Annexin V and 7-AAD staining was performed. A higher frequency of non-viable CD8+ H60+ T cells in the spleen (> 50%) compared to the BM (<30%) compartments was observed 2 weeks after allogeneic HCT. Such findings may reflect that activation-induced cell death in the spleen induced by antigen in the allogeneic HCT was greater than in the bone marrow. Thus, reduced apoptosis in the marrow microenvironment could reflect survival advantage for CD8+ TM in this compartment. Current studies are determining the effects of ablative conditioning on ex vivo effector function activity of MiHA-specific CD8+ TM

Pre-Transplant Infusion of Donor CD4+ CD25+ T Cells Suppresses Host Anti-Donor MiHA-Specific CD8 T Cells and Facilitates Stable Mixed Chimerism Following MHC-Matched Allogeneic Marrow Transplant

Abstract Surmounting the barrier mediated by host T cells against successful engraftment of MHC-matched allogeneic marrow is a crucial objective of hematopoietic stem cell transplant (HCT). We proposed that the ability of unmanipulated donor CD4+ CD25+ regulatory T cells (Tregs) to suppress activation of host effector CD8+ T cells would enhance donor HC engraftment between strains disparate for multiple minor HA (MiHA), and promote stable chimerism. C57BL/6 (H-2b, Ly9.1−) mice conditioned (5.5 Gy TBI) 24 hrs earlier, were transplanted with Tregs and TCD-BM from 129P3/J (H-2, Ly9.1+) mice. By four weeks post-HCT, the mean frequency of circulating donor-derived (total Ly9.1+) cells was 15.7 ± SE 5.9% in recipients of 4 × 106 TCD-BM + Tregs (4.5 × 105) compared to the absence of donor chimerism in recipients of allogeneic HCT only (0.3 ± 0.09%) - a finding also evident from the analysis of circulating donor B220+ cells (8.7 ± 3.0 vs. 0.2 ± 0.06%). Based on these findings, we hypothesized that pre-HCT infusion of Tregs into a lymphopenic, allogeneic host might enhance their facilitating function. Accordingly, Tregs (4 or 1.5 × 105) were transplanted 24hr. post-conditioning either 3 days prior to HCT or co-transplanted with (day 0) donor TCD-BM. The transplant was rejected in recipients not administered donor Tregs. The higher dose of Tregs administered pre-transplant or co-transplanted facilitated equivalent donor cell chimerism. In contrast, administration of 1.5 × 105 Tregs resulted in chimerism only when this donor population was infused 3 days prior to HCT (1.6±0.9%). To test the hypothesis that donor Tregs suppressed host anti-donor specific CD8 T cells, we monitored host CD8+ T cell responses to the immunodominant donor epitope H60 by tetramer staining (LTFNYRNL/Kb). One month post-HCT of TCD-BM alone, the frequency of circulating tetramer+ CD8+ cells in these recipients rejecting the marrow graft was clearly greater compared to the frequency in recipients of TCD-BM + Tregs which engrafted (p0.05). Notably, transplants using unmanipulated host Tregs failed to support engraftment. These findings illustrate that donor Tregs support chimerism via suppression of host anti-donor antigen-specific T cells. Finally, the persistence of donor cells in circulation as well as in lymphoid tissues 3 months post-HCT indicated that long-term, stable chimerism was established by this Treg administration regimen. In total, our results demonstrate that donor Tregs promote MHC-matched allogeneic marrow engraftment under conditions of reduced intensity conditioning and that the strategy of pre-HCT Treg infusion supports the notion that antigen driven expansion of donor anti-host reactive Treg cells prior to stem cell transplants can increase their efficacy to facilitate hematopoietic engraftment. Experiments to study transient vs. long-term engraftment and expansion of donor Treg cells are being examined

Minor Histocompatibility Antigen-Specific CD8+ Memory T Cells in Hematopoietic Compartments Survive the Immediate Non-Ablative and Ablative TBI Milieu

Abstract Minor histocompatibility (MiHA) antigens induce CD8+ T-cell responses that mediate resistance to bone marrow engraftment in an MHC-identical, MiHA-disparate marrow transplant model, in which recipients are sensitized to donor antigens (BALB.B à B6BALB.B) prior to BMT. The H60 H antigen has been shown to dominate the immune response in B6 mice primed with BALB.B antigens (B6BALB.B). We initially sought to determine the distribution and partially characterize the phenotype of H60-specific CD8+ cells in the blood, spleen and marrow compartments of B6 mice primed with 3 x 107 BALB.B lymphoid cells and ≥3 weeks later boosted with 2 x 107 cells. An H60 tetramer (LTFNYRNL/H2-Kb) conjugated to PE was used to detect H60-specific CD8+ cells in these compartments. Eight days following the second immunization, the mean frequency of circulating H60-specific cells was 12.2% ± SE 0.88 of CD8+ cells (range: 5.6 – 20.5%). The frequency of splenic H60-specific CD8+ cells was equivalent to that of circulating antigen-specific cells, thus peripheral blood levels of H60-specific CD8+ cells appear to be representative of those resident in the spleen. Interestingly, in the marrow compartment, the frequency of H-60+ cells amongst the CD8 T cell population was higher compared to peripheral blood and spleen levels, suggesting that H60-specific CD8+ cells in this compartment may comprise both migrant cells from the periphery and resident cells in the marrow elicited during priming. In both BM and spleen, >90% of CD8+ H60+ cells expressed the memory phenotype(CD44+, Ly6C+) and as expected, did not express early activation markers (CD25, CD69). To mediate resistance to progenitor cell engraftment, H60-specific effector CD8+ cell must first survive the immediate post-BMT milieu in the hemopoietic compartments. To examine this question, B6BALB.B mice irradiated at 3.0, 6.0 and 9.0 Gy were analyzed 24 hours later for the presence of H60-specific CD8+ cells in the spleen and marrow compartments. Although there was an expected irradiation dose-dependent decrease in absolute numbers of CD8+ H60+ cells in the two compartments, there was a dose-dependent increase in percent of CD8+ T cells expressing the H60 TCR in both compartments. This observation indicates enhanced survival of these antigen-specific CD8+ memory T cells post-conditioning. Preliminary results indicate that 24h post-BMT into 9.0 Gy TBI recipients, there was BrDU uptake in marrow and splenic CD8+H60+ T cells in B6BALB.B transplanted with 1 x 107 BALB.B BM-TCD. Approximately 80% of CD8+H60+ T cells in the marrow compartment of primed recipients of BALB.B cells exhibited proliferation by BrDU uptake. Thus, donor MiHA-disparate marrow grafts elicit antigen-driven proliferation early post-BMT by CD8+ memory T cells in both compartments consistent with the potential importance of these cells in mediating resistance against progenitor engraftment across these MiHA differences

Identification of a Single MiHA Specificity That Induces Resistance to MHC-Matched Allogeneic HCT

Abstract T cell populations specific for transplantation antigens have been detected in sensitized individuals following multiple blood transfusions, marrow transplants as well as in multiparous females. Resistance to allogeneic hematopoietic cell transplant (HCT) in such sensitized individuals is consistent with the presence of a host memory T cell (TM) population specific for donor cell antigens. We hypothesized that a single donor minor histocompatibility (MiHA) epitope could elicit antigen-specific CD8 TM capable of resisting MHC-matched allogeneic hematopoietic cell engraftment. To address this question, CD8 TM were generated against a single MiHA epitope to determine if such cells could mediate resistance after ablative TBI conditioning. B6 mice were sensitized 2X to the H60 immunodominant MiHA epitope utilizing bone marrow-derived dendritic cells pulsed with the H60 (LTFNYRNL) peptide. Three weeks following booster sensitization, CD8 T cells were detected by tetramer staining in peripheral blood samples. These T cells exhibited a phenotype characteristic of memory cells (CD44hi, Ly 6C+). B6 (H2b) mice containing CD8+ H60+ T cells were subsequently conditioned with 9.0 Gy TBI and transplanted with 5 × 106 BALB.B (H2b) BM-TCD. One week post-transplant, naive recipients of BALB.B (H60+) or B6-H60 congenic TCD-BM contained >10-fold higher levels of circulating donor cells than the B6 dendritic cell/peptide sensitized recipients. Donor progenitor cells were also found to be significantly reduced in sensitized recipients of allogeneic TCD-BM at this time. Two weeks post-HCT, recipients of syngeneic marrow exhibited >10-fold greater frequency of circulating donor cells compared to recipients of MHC-matched allogeneic marrow (< 5% donor chimerism was detected). These findings demonstrate that host T cells with specificity against a single donor MiHA determinant are sufficient to induce resistance to MHC-matched allogeneic marrow engraftment. Such observations regarding the effector response of HVG contrast those by donor T cell responses post-transplant in which single MiHA differences fail to induce GVHD. Finally, heterologous immunity to virus has been reported to generate allo-reactive TM cells. Since such TM repertoires could include specificity for MiHA immunodominant epitopes, the presence of TM populations that can mediate resistance in “naive” recipients may be more prevalent than hitherto appreciated

Engraftment of splenic tissue as a method to investigate repopulation by hematopoietic cells from host and donor marrow

The lymphohematopoietic function of the spleen in mice varies dependent on age and hematopoietic requirements. A method was developed to study splenic repopulation of mature and progenitor cell populations by grafting neonatal or adult spleen tissue under the renal capsule of splenectomized mice. Two weeks following implant of irradiated syngeneic neonatal spleens into B6-Ly 5.1 or B6-gfp recipients, host lymphoid (B220(+), CD4/8(+)) and myeloid cells (CD11b(+)) had repopulated the splenic grafts and constituted the majority of cells contained in these heterotopic implants. Notably, the percentage of lymphoid and myeloid cells approximated adult levels in contrast to preimplant neonatal spleen levels. This observation indicated relatively rapid repopulation of the grafted tissue by adult host cells and suggests that the repopulation patterns were regulated by the host. Three months post-implantation, the cell composition in the graft remained comparable to adult levels. Microscopic examination demonstrated normal splenic architecture including follicles and red pulp. Lymphocytes within the graft were functional as indicated by their proliferation in response to lipopolysaccharide (LPS) and concanavalin A (ConA) stimulation. Progenitor cell activity determined by colony-forming unit interleukin-3 (CFU-IL-3) levels was also present in these grafts. Splenic implants were then assessed in transplant models following lethal irradiation and syngeneic or allogeneic bone marrow transplantation (BMT). Two weeks post-BMT, adult splenic tissue implants contained donor-derived B cells, T cells, and myeloid cell populations. As typically detected in the host spleen post-BMT, the grafted tissue also contained elevated levels of donor progenitor cells. By 3 months post-BMT, CFU-IL3 levels in the graft reflected the decreased levels characteristic of adult levels. The functional integrity of post-transplant splenocytes in the implants was also demonstrated by mitogenic responsiveness. In summary, this method should provide a useful model for the transfer of the splenic microenvironment to study the biology of the spleen in non-transplant and BMT settings