小鼠脐血造血干/祖细胞含量与特性初步观察

目的: 探讨小鼠脐血(umbilicalcordblood, UCB)造血干/祖细胞含量与特性。方法: 采用体外集落培养和流式细胞术检测C57BL/6(H-2^b)小鼠脐血与骨髓(bonemarrow, BM)造血干/祖细胞。结果: 小鼠脐血培养7d粒单系祖细胞(CFU-GM)及早期红系祖细胞(BFU-E)集落产率与骨髓相近, 但14dCFU-GM、多向祖细胞(CFU-GEMM)明显高于后者(P<0.05), 且见含细胞多体积巨大的致密型集落。脐血CD₃₄⁺Sca-1⁺细胞亚群也明显高于骨髓(P<0.05)。结论: 小鼠F脐血富含造血干/祖细胞, 具有高增殖潜能。     

CD34+细胞的心肌细胞分化潜能研究

目的:了解粒细胞集落刺激因子(G-CSF)动员的CD34+细胞的心肌细胞分化潜能。方法:用异丙肾上腺素(ISO)复制急性心肌梗死大鼠动物模型,于3 h后用G-CSF动员骨髓造血干细胞进行心肌梗死动物模型的“自身干细胞移植”,用免疫组化和HE染色方法检测动物模型心梗区的CD34⁺细胞浸润以及心肌细胞再生情况。结果:用ISO后24 h,G-CSF处理组大鼠心梗区可见大量CD34⁺单个核细胞浸润,并有CD34⁺的新生心肌细胞生长,2周后疤痕组织不明显;而对照组心梗坏死区有大量以中性粒细胞为主的炎症细胞浸润,无CD34+细胞浸润及新生心肌细胞生长,2周后出现较大量的疤痕组织。结论:G-CSF动员CD34⁺细胞具有向心肌细胞分化的潜能,用G-CSF 动员造血干细胞的“干细胞自身移植”,可治疗急性心肌梗死。     

骨髓间质干细胞输注对外周血干细胞移植造血恢复的影响

目的:观察骨髓间质干细胞 (MSCs)输注对外周血干细胞移植 (PBSCT)后造血恢复的影响。方法:去脾小鼠经粒细胞集落刺激因子动员后收获外周血单个核细胞 (PBMC)和扩增培养的骨髓间质干细胞 (MSCs),移植给经放 /化疗预处理的BALB/c小鼠,数量分别为10⁶PBMC(PBSCT组)、10⁴MSCs和10⁶ PBMC(实验1组)、10⁶ MSCs和10⁶ PBMC(实验 2组),观察受体鼠 4周的生存率、骨髓有核细胞 (BMNC)、粒细胞巨噬细胞集落形成单位 (CFU-GM)、成纤维细胞集落形成单位 (CFU-F)、外周血白细胞 (WBC)计数等指标。结果:实验 2组的生存率、BMNC、CFU-GM、CFU-F显著高于PBSCT组,WBC计数恢复较PBSCT组快 (P <0.05);实验1组和PBSCT组比较,WBC计算恢复快,CFU-F产率高 (P <0.05)。结论:骨髓间质干细胞输注有促进外周血干细胞移植造血恢复的作用。     

真性红细胞增多症患者骨髓单个核细胞植入再生障碍性贫血小鼠

背景：真性红细胞增多症患者骨髓的高增殖低凋亡特性使其造血干细胞植入NOD/SCID小鼠后成功分化出粒红系细胞,但其能否植入并改善再生障碍性贫血小鼠造血功能,目前国内外尚未有报道。 目的：探讨JAK2阳性真性红细胞增多症患者骨髓单个核细胞植入后对再生障碍性贫血小鼠造血重建的影响。 方法：应用注射用重组人γ-干扰素联合白消安的方法建立再生障碍性贫血小鼠模型,随机分为实验组(n=10)和对照组(n=10),给药结束后第5天实验组经尾静脉输注真性红细胞增多症患者骨髓单个核细胞悬液,对照组同法输注等容积生理盐水。输注后第14天检测小鼠外周血常规、骨髓细胞形态、骨髓组织病理变化以及小鼠外周血和骨髓内CD45+细胞的百分含量。 结果与结论：输注后第14天,实验组小鼠血细胞计数三系减少,骨髓涂片可见散在淋巴细胞和早期造血细胞,骨髓组织活检可见骨髓增生减低,少量粒系细胞及幼红细胞,未见巨核细胞,与对照组比较,造血功能无明显改善。对照组小鼠外周血及骨髓均未检测到CD45+细胞,实验组小鼠外周血及骨髓均可检测到人源化的CD45+细胞,且骨髓中CD45+细胞比外周血高,提示JAK2V617F阳性真性红细胞增多症患者骨髓单个核细胞能成功植入再生障碍性贫血小鼠体内,但血常规、骨髓涂片及活检结果显示未能明显改善骨髓造血功能。  中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程     

系统性红斑狼疮患者外周血淋巴细胞表达BLyS和CD38的变化

目的:研究系统性红斑狼疮(SLE)患者外周血淋巴细胞表达BLyS和CD38的变化。方法:收集22名SLE患者和14名健康人外周血淋巴细胞, 用流式细胞仪检测外周血淋巴细胞表达BLyS和CD38的变化。结果:SLE患者外周血BLyS⁺淋巴细胞、CD19⁺淋巴细胞和CD19⁺CD38⁺淋巴细胞显著增加, BLyS⁺淋巴细胞增加与CD19⁺CD38⁺淋巴细胞增加呈正相关(r=0.434, P<0.05).结论:SLE患者外周血淋巴细胞表达BLyS和CD19⁺B淋巴细胞表达CD38均显著增加, 且二者增加呈正相关。     

培养前后脐血CD34~＋细胞在NOD/SCID鼠体内造血重建功能的比较

目的:以NOD/SCID小鼠为模型, 经半致死剂量照射后输注新鲜或培养后的造血细胞, 以比较培养前后脐血CD34 细胞的造血重建功能.方法:从新鲜脐血中分离单个核细胞(MNC), 采用干细胞因子(SCF)、血小板生成素(TPO)、Flt3配体(FL)、白细胞介素3(IL-3)和白细胞介素6(IL-6)细胞因子组合体外培养14 d.通过MiniMACS免疫磁性吸附柱从新鲜或培养后的MNC中分离CD34 细胞, 4×105个CD34 细胞和5×106CD34-细胞混合后通过尾静脉输注入NOD/SCID小鼠中.饲养过程中动态观察外周血象恢复情况, 6周后检测小鼠骨髓和脾脏细胞中人源细胞及各系造血细胞的含量.结果:体外培养MNC 14 d后, 总细胞扩增了1.78倍;细胞移植6周后, 输注新鲜和培养后造血细胞的小鼠均存活, 在小鼠骨髓和脾脏中均可检测到人源细胞及各系人源血细胞和人特异ALU基因序列, 小鼠外周血象恢复到辐照前水平.培养后CD34 细胞在小鼠体内的植入水平与新鲜CD34 细胞的相近, 而其各系人源血细胞的含量高于新鲜CD34 细胞. 结论:体外培养14 d后的CD34 细胞仍保持了体内植入和重建造血的能力, 且其多系造血重建能力优于新鲜CD34 细胞.     

大鼠骨髓间质干细胞基本生物学特性的研究

目的:研究成年大鼠骨髓间质干细胞(rBMMSCs)的基本生物学特性,并与成人骨髓间质干细胞(hBMMSCs)作比较。方法:分别采用贴壁法和Ficoll-Paque淋巴细胞分离法分离获得rBMMSCs和hBMMSCs,进行体外传代、扩增、纯化,比较分析不同代数的rBMMSCs和hBMMSCs的增殖能力和克隆形成能力,观察传代次数对rBMMSCs的神经分化能力的影响,流式细胞仪检测rBMMSCs表面抗原表达;采用中期分裂相秋水仙素阻抑法分析rBMMSCs的核型。结果:原代rBMMSCs和hBMMSCs在体外扩增后可分别获得(7-8)×10⁵和(5-6)×10⁵个细胞,体外扩增5代后可分别获得1.7×10⁸和l×10⁸个细胞,体外扩增15代后,可分别获得(4-8)×10¹²和(3-4)×10¹²个细胞,随着传代次数的增加,细胞的增殖能力、克隆形成能力和神经分化能力有所下降,但各代rBMMSCs的增殖能力和克隆形成能力都比hBMMCs较强。流式细胞仪检测结果显示rBMMSCs的CDllb、CD45、CD61、CD71、CD8O、CD86、MHCⅠ、MHCⅡ表达为阴性,而CD29和CD44表达阳性。rBMMSCs为正常大鼠二倍体核型。结论:rBMMSCs具有极强的自我更新能力和神经分化能力,是一种具有正常二倍体核型的间质干细胞,在组织工程中具有广阔的应用前景。     

人源化NOD/SCID小鼠免疫细胞的动态变化与鉴定

目的： 比较脐血干细胞与单个核细胞移植NOD/SCID鼠所建立的人源化SCID模型，分析人源化淋巴细胞重建。方法： 磁珠分选法分离脐血中CD34⁺细胞，淋巴细胞分层液分离脐血单个核细胞，分别经尾静脉输入NOD/SCID小鼠。每隔2周采血至10周，流式细胞术动态检测人源淋巴细胞CD45、CD19、CD3抗原。第10周处死小鼠收集外周血、骨髓、胸腺组织，RT-PCR检测模型鼠组织中人β₂M基因及RAG2基因。结果： 两种类型细胞移植均可重建人源免疫细胞，人源淋巴细胞表达水平均在第8周达高峰。骨髓中人源淋巴细胞表达水平明显高于外周血。RT-PCR在外周血与骨髓检测到人β₂M基因及RAG2基因标志。结论： CD34⁺细胞移植重建人源化NOD/SCID免疫系统模型效果要好于脐血单个核细胞。人源T淋巴细胞在模型鼠骨髓中分化成熟。     

补肾活血中药对免疫介导再障小鼠骨髓CD45+细胞的影响

目的:观察补肾活血中药对免疫介导再障小鼠CD₄₅⁺细胞的影响。方法:建立免疫介导再障小鼠模型,随机分组胃饲生理盐水、高剂量中药、低剂量中药、环孢素A(CsA),并设正常对照,第10d分别称体重、计算外周血细胞和骨髓有核细胞数、采用流式细胞技术测定骨髓CD₄₅⁺细胞。结果:中药组小鼠体重、外周血细胞、骨髓有核细胞数、骨髓CD₄₅⁺细胞显著高于空白模型组和CsA组,而接近正常对照组。结论:补肾活血中药对免疫介导再障小鼠的骨髓造血细胞有保护作用。     

NK细胞在小鼠异基因骨髓移植中的作用

目的:研究自然杀伤(NK)细胞在异基因骨髓移植中对移植物抗宿主病(GVHD)、移植排斥、骨髓植入及造血重建的影响。方法:以近交系小鼠C57/6j(H-2^b)为供鼠、BALB/c(H-2^d)为受鼠,在移植物中增加供者的外周T细胞和/或NK细胞进行异基因骨髓移植,用流式细胞仪检测受鼠的CD₃₄^＋细胞计数和H-2K^b＋细胞表达水平,血细胞自动分析仪检测外周血白细胞计数,并结合临床表现和病理检查,比较不同移植组的存活率、GVHD、植入水平及造血重建等。结果:增加NK细胞组的小鼠存活率显著大于不增加NK细胞组,小鼠出现GVHD的数量少、程度轻,外周血白细胞及骨髓CD₃₄^＋细胞恢复快、H-2K^b＋细胞表达水平高。结论:NK细胞抑制小鼠异基因骨髓移植中的GVHD和移植排斥,促进骨髓植入及造血重建。     

A Novel Population of Mesenchymal Progenitors with Hematopoietic Potential Originated from CD14- Peripheral Blood Mononuclear Cells

Hemopoietic system derived progenitor cells with mesenchymal features have been identified including CD14⁺ monocyte-derived progenitors. However, it is unclear whether there are mesenchyme derived progenitors with hematopoietic potential. Herein, we identified a novel CD14^- cell-derived population with both mesenchymal and hematopoietic features in rat peripheral blood, and this cell population is different from the CD14⁺ monocyte-derived progenitors but designated peripheral blood multipotential mesenchymal progenitors (PBMMPs). Phenotype analysis demonstrated expression of mesenchymal markers in PBMMPs including BMPRs, Endoglin/CD105, Fibronectin (Fn), Vimentin (Vim), Collagen (Col) I/II/III along with hematopoietic marker CD34. CD14⁺ cell-derived population shared the same characteristics with CFs. In mixed culture of CD14⁺ and CD14^- cells, PBMMPs were a predominant component and expressed CD29^high, CD73^high, CD34^high, CD45^low and CD90. Except for the value of mixed T lymphocytes and CD14⁺ cell-derived population, hematopoietic characters of cultured PBMMPs were indicated by CD14^-/CD34⁺/CD45^-/CD90⁺. The mesenchymal origin was further confirmed by comparing PBMMPs with bone marrow stromal cells. Finally, we transplanted PBMMPs into a skin wound model, and results showed the specific potential of PBMMPs in not only extracellular matrix secretion but epidermal regeneration. This study provides evidence that peripheral blood contains common hematopoietic-mesenchymal progenitors from both hematopoietic and mesenchymal lineages, and CD34⁺ mesenchymal progenitors are a possible alternative source of epidermal cells in wound healing.     

Transduction of umbilical cord blood CD34+ NOD/SCID-repopulating cells by simian foamy virus type 1 (SFV-1) vector

Foamy viruses are nonpathogenic retroviruses that offer unique opportunities for gene transfer into various cell types including hematopoietic stem cells. We used a simian foamy virus type 1 vector (SFV-1) containing a LacZ reporter gene with a titer of 1-5 x 10(6) viral particles/ml that was free of replication-competent retrovirus to transduce human umbilical cord blood CD34+ cells. Transduced CD34+ cord blood cells were transplanted into NOD/SCID mice and plated in serum-free methylcellulose culture to determine the transduction efficiency of human hematopoietic progenitor cells. A transduction efficiency of about 20% was obtained. At 6-10 weeks posttransplantation, human hematopoietic cell engraftment and marking were determined. Marrow from transplanted mice demonstrated human cell engraftment by the presence of human (CD45+) cells containing both CD19+ lymphoid and CD33+ myeloid cells. Serial sampling of NOD/SCID bone marrow revealed the presence of 6.7-14.0% CD45+ cells at 6 weeks posttransplant as compared to 3.6-27.2% CD45+ cells at 9-10 weeks posttransplant. Human progenitors examined from NOD/SCID bone marrow cells 9 weeks posttransplant revealed from 7.4 to 25.9% of the colonies exhibiting X-gal staining. Our study demonstrates the ability of a simian foamy virus vector to transduce the SCID-repopulating cell and offers a promising new gene delivery system for use in hematopoietic stem cell gene therapy.     

Immunomodulatory function of whole human umbilical cord derived mesenchymal stem cells

Bone marrow derived mesenchymal stem cells (MSCs) play a critical role in immune modulation. However, immunomodulatory function of whole human umbilical cord derived mesenchymal stem cells (UC-MSCs) remains unclear. In this study, UC-MSCs were separated from whole umbilical cord using a single enzyme digestion. UC-MSCs (CD73⁺, CD90⁺, CD105⁺, and CD34⁻, CD45⁻, HLA-DR⁻) were differentiated into adipocytes, osteocytes and chondrocytes in vitro under specific stimulatory environments. UC-MSCs suppressed umbilical cord blood lymphocyte proliferation stimulated by mitogen, and ELISA showed that the secretion of INF-γ was downregulated, and the secretion of IL-4 was upregulated, with CD8⁺ T cells markedly decreased and CD4⁺ T cells changed lightly. Moreover, the infusion of UC-MSCs in recipient mice transplanted with donor bone marrow cells ameliorated acute graft-versus host disease (aGVHD) and extended survival. In conclusion, UC-MSCs might negatively modulate immunoreactions, and have application potential in the treatment of aGVHD caused by allogeneic stem cells transplantation.     

体外分化胚胎干细胞为造血干细胞重建造血功能的研究

目的：探讨体外定向分化胚胎干细胞（ESCs）为造血干细胞（HSCs）对体内造血功能的重建作用。方法：将小鼠E14.1胚胎干细胞采用“三步诱导法”在体外分化发育为HSCs，造血克隆形成(CFU)实验观察其体外造血集落形成情况，免疫磁珠分选纯化HSCs移植给经亚致死剂量γ射线照射的雌性SCID小鼠，观察其植入及小鼠造血功能恢复情况。结果: 经过分阶段诱导，多种造血刺激因子联合应用能有效促进ESCs定向分化发育为HSCs,流式细胞仪检测HSCs特异性表面标志物CD34+/Sca-1+表达最高为（58.64±4.20）%，CFU培养能形成较多的红系、粒系/巨噬细胞系及混合细胞集落, Wright-Giemsa 染色显示为原始的造血细胞。此阶段的HSCs经分选纯化后移植给经γ射线照射后的小鼠，移植组小鼠+10 d造血功能开始恢复，观察40 d后除血小板恢复较慢外，白细胞、红细胞、血红蛋白等指标已接近正常，植入率为71.4%，存活率为43.0%，染色体检测证实已由受体鼠的XX转为供体鼠的XY。结论: 采用分阶段诱导的方法，可在体外定向诱导小鼠ESCs分化发育为HSCs，此来源的HSCs可以有效重建体内造血功能。     

Adoptive Transfer of Low Numbers of CD4+ T Cells into SCID Mice chronically treated with Soluble IL-4 Receptor does not prevent Engraftment of IL-4-Producing T Cells

After intravenous injection of 10⁵ purified, lymph node (LN)-derived dm2 (H-2^d/L^d) CD4⁺ T cells into young C.B-17 scidjscid (severe combined immunodeficiency, SCID) mice (H-2^d/L^d+), the transplanted L^d- T cells show a selective pattern of engraftment: they repopulate the spleen, the lamina propria of the small intestine and the mesenteric LN (but not other peripheral LN) of the immunodeficient host. CD4⁺ cells repopulating different lymphoid organs of the SCID recipient mice produce interleukin-2 (IL-2) and interleukin-4 (IL-4) in response to polyclonal stimulation in vitro. Some evidence has recently been provided that cytokines (e.g. IL-4) present at the site of antigen stimulation in vivo decisively influence the pattern of cytokines expressed by T cells activated at these sites. We therefore asked if neutralization of IL-4 by chronic treatment of SCID mice with high doses of recombinant soluble IL-4 receptor (sIL-4R) changes the IL-4 or IL-2 expression pattern of CD4⁺ T cells adoptively transferred into young SCID recipients. Transplanted SCID mice were chronically treated with two different, recombinant murine sIL-4R proteins. The experimental series further included groups of transplanted SCID mice treated with a recombinant human sIL-4R protein (which does not bind murine IL-4), treated with the anti-murine IL-4 monoclonal antibody (MoAb) 11B11, or non-treated. Transplanted SCID mice treated with the recombinant murine sIL-4R protein preparations displayed detectable sIL-4R serum levels, which demonstrates that the substitution therapy could maintain neutralizing serum levels of anti-IL-4 activity in SCID mice. By contrast, no serum sIL-4R levels were detectable in the sensitive ELISA readout in transplanted SCID mice which were non-treated, treated with the MoAb 11B11, or treated with the recombinant human sIL-4R protein. The efficiency and the pattern of CD4⁺ T-cell engraftment, and the lymphokine-producing phenotype of the engrafted dm2 CD4⁺ cells, was not affected by the continuous IL-4-neutralizing treatment of mice with either the MoAb 11B11 or the soluble IL-4R preparations. Hence, in contrast to the published evidence of the dramatic effect of IL-4 on the lymphokine-producing phenotype of CD4⁺ T cells stimulated in vitro or in vivo, the chronic suppression in vivo of IL-4 activity (by either different sIL4-R protein constructs, or by the anti-IL-4 MoAb 11B11) did not lead to preferential engraftment of Th1-type CD4⁺ T cells after adoptive transfer of CD4⁺ T-cell populations into an immunodeficient recipient.     

Cytotoxic reactivity of gut lamina propria CD4+ αβ T cells in SCID mice with colitis

Polyclonal, mucosa-seeking memory/effector CD4⁺ T cells containing a large fraction of blasts activated in situ accumulate in the gut lamina propria of severe-combined immunodeficient (SCID) mice developing colitis after CD4⁺ T cell transplantation. CD4⁺ T cells isolated from different repopulated lymphoid tissues of transplanted SCID mice proliferate in vitro in the presence of interleukin (IL)-2 + IL-7. CD3 ligation enhances this cytokine-supported proliferation in CD4⁺ T cells from the spleen and the mesenteric lymph node of transplanted SCID mice; CD3 ligation suppresses the cytokine-supported proliferation in CD4⁺ T cells from the gut lamina propria in a cell density- and dose-dependent manner. Almost all CD4⁺ T cells from repopulated lymphoid tissues of transplanted SCID mice express CD95 (Fas) on the cell surface, and a large fraction of CD4⁺ T cells from the gut lamina propria of transplanted SCID mice express the Fas ligand on the surface. Gut lamina propria CD4⁺ T cells show Fas-dependent cytotoxicity. A large fraction of gut lamina propria CD4⁺ T cells that infiltrate the inflamed colon in transplanted SCID mice are activated in situ and many CD4⁺ T cells are apoptotic. Hence, a large fraction of colitis-inducing CD4⁺ T cells undergo activation-induced cell death in situ and can damage other cells through Fas-dependent cytotoxicity.     

Co-expression of CD8α in CD4+ T cell receptor αβ+ T cells migrating into the murine small intestine epithelial layer

We investigated the surface phenotype of CD3⁺CD4⁺ T cell receptor (TCR) αβ⁺ T cells repopulating the intestinal lymphoid tissues of C.B-17 scidlscid (severe-combined immunodeficient; scid) (H-2^d, L^d+) mice. CD4⁺ CD8^? T cells were cell sorter-purified from various secondary and tertiary lymphoid organs of congenic C.B-17 +/+ (H-2^d, L^d+) or semi-syngeneic dm2 (H-2^d, L^d?) immunocompetent donor mice. After transfer of 10⁵ cells into young scid mice, a mucosa-homing, memory CD44^hi CD45RB^lo CD4⁺ T cell population was selectively engrafted. Large numbers of single-positive (SP) CD3⁺ CD2⁺ CD28⁺ CD4⁺ CD^8? T cells that expressed the α₄ integrin chain CD49d were found in the spleen, the mesenteric lymph nodes, the peritoneal cavity and the gut lamina propria of transplanted scid mice. Unexpectedly, large populations of donor-type doublepositive (DP) CD4⁺ CD8α⁺ CD8β^? T cells with high expression of the CD3/TCR complex appeared in the epithelial layer of the small intestine of transplanted scid mice. In contrast to SP CD4⁺ T cells, the intraepithelial DP T cells showed low expression of the CD2 and the CD28 co-stimulator molecules, and of the α₄ integrin chain CD49d, but expressed high levels of the α_IEL integrin chain CD103. The TCR-Vβ repertoire of DP but not SP intraepithelial CD4⁺ T cells was biased towards usage of the Vβ6 and Vβ8 viable domains. Highly purified populations of SP and DP CD4⁺ T cell populations from the small intestine epithelial layer of transplanted scid mice had different abilities to repopulate secondary scid recipient mice: SP CD4⁺ T cells repopulated various lymphoid tissues of the immunodeficient host, while intraepithelial DP CD4⁺ T cells did not. Hence, a subset of CD3⁺ CD4⁺ TCRαβ⁺ T cells apparently undergoes striking phenotypic changes when it enters the microenvironment of the small intestine epithelial layer.     

Failure of tumor-reactive lymph node cells to kill tumor in the presence of immune-suppressive CD34+ cells can be overcome with vitamin D3 treatment to diminish CD34+ cell levels

Growth of Lewis lung carcinoma (LLC-LN7) tumors results in an increase in CD34⁺ granulocyte-macrophage progenitor cells having natural suppressor (NS) activity. These CD34⁺ NS cells were capable of inhibiting the cytotoxic activity of tumor-reactive lymph node cells. In vivo studies showed that adoptive treatment of LLC-LN7 tumor-bearing mice with tumor-reactive lymph node cells plus IL-2 failed to reduce the development of metastases. Studies were conducted to determine if diminishing the levels of CD34⁺ NS cells would allow for improved anti-tumor effectiveness of the adoptively transferred cells. The suppressive activity of CD34⁺ cells toward the cytolytic activity of tumor-reactive lymph node cells could be blocked by in vitro culture of CD34⁺ cells with the differentiation-inducing hormone 1a,25-dihydroxyvitamin D₃. Similarly, treatment of LLC-LN7-bearing mice with vitamin D₃ alone diminished the levels of CD34⁺ NS cells within regional lymph nodes, spleens and tu mors. This treatment resulted in an increased immune reactivity to autologous tumor, as shown by the production of IFN-g by lymph node cells in response to the presence of LLC-LN7 cells. The extent of tumor metastasis in mice receiving vitamin D₃ treatment was also reduced. When tumor-reactive lymph node cells were adoptively transferred into these LLC-LN7-bearing mice that were receiving vitamin D₃ treatment, there resulted a pronounced synergistic reduction in tumor metastasis. The results of this study show that treatment of tumor bearers with vitamin D₃ to eliminate CD34⁺ NS cells improves the anti-tumor effectiveness of adoptively transferred tumor-reactive lymph node cells. © Rapid Science 1998