Defect of CD8^＋ Memory T Cells Developed in Absence of IL-12 Priming for Secondary Expansion

IL-12 priming plays an important role in stimulation of CD8^＋ effector T cells and development of CD8^＋ memory T （Tm） cells. However, the functional alteration of CD8^＋ Tm cells developed in the absence of IL-12 priming is elusive. In this study, we investigated the capacity of secondary expansion of CD8~ Tm cells developed from transgenic OT I CD8^＋ T cells. The latter cells were in vitro and in vivo stimulated by ovalbumin （OVA）-pulsed dendritic cells [DCovA and （IL-12^-/-）DCovA] derived from wild-type C57BL/6 and IL-12 gene knockout mice, respectively. We demonstrated that IL-12 priming is important not only in CD8^＋ T cell clonal expansion, but also in generation of CD8^＋ Tm cells with the capacity of secondary expansion upon antigen re-encounter. However, IL-12 signaling is not involved in CD8^＋ Tm cell survival and recall responses. Therefore, this study provides useful information for vaccine design and development. Cellular ＆ Molecular Immunology.     

Anti-Idiotypic Regulatory Responses Induced by Vaccination with DNA Encoding Murine TCR Vα5 and Vβ2

There is evidence suggesting that anti-idiotypic regulation against T cells plays a role in maintaining homeostasis in the immune system, although its mechanism is not fully understood. By using DNA constructs encoding the TCR Vα5.2 and Vβ2.1 chains derived from ：in ovalbumin （OVA）-specific T cdl clone （OVA-T）, we herein demonstrated that vaccination with TCR-DNA effectively induced anti-idiotypic cellular as well as humoral responses. Serum samples from the TCR-DNA-vaccinated BALB/c mice were able to stain T cells in an idiotype-specific manner. CD4^＋ T cells from the TCR-DNA-vaccinated mice proliferated in response to stimulation with irradiated syngeneic OVA-T calls and secreted interferon-y but very little IL-4. Splenocytes from the TCR-DNA-vaccinated mice showed strong idiotype-specific CTL activity against the OVA-T cdls. Furthermore, adoptive transfer of the CD4^＋ or CD8^＋ T cells from the TCR-DNA-vaccinated mice resulted in hyporesponsiveness of syngeneic recipients. These results demonstrated that vaccination with DNA encoding TCR can effectively activate anti-idiotypic regulatory responses in vivo and thus providing a useful way for immunological intervention.     

Deficiency of Mouse CD4^＋CD25^＋Foxp3^＋ Regulatory T Cells in Xenogeneic Pig Thymus-Grafted Nude Mice Suffering from Autoimmune Diseases

Xenogeneic thymus transplantation can efficiently induce specific immune tolerance to donor antigens in athymic recipients. However, many nude mice suffer from autoimmune diseases （AID） for over 10 weeks after xenogeneic thymus transplantation. CD4^＋CD25^＋Foxp3^＋ regulatory T （Treg） cells were recently determined to play a pivotal role in keeping immune tolerance in humans and mice. Thus, we investigated this subpopulation of Treg cells in the periphery of pig thymus-grafted nude mice suffering from AID. Our results showed that the expression of Foxp3, CTLA-4 and GITR on mouse CD4^＋CD25^＋ T cells and the ratio of CD4^＋CD25^＋Foxp3^＋ Treg cells to CD4^＋ T cells were significantly decreased in the periphery of pig thymus-grafted nude mice suffering from AID, compared with healthy pig or mouse thymus-grafted nude mice. Furthermore, mouse CD4^＋CD25^＋ T cells in pig thymus-grafted nude mice suffering from AID showed more severe deficiency in immunosuppressive function compared with the counterpart in xenogeneic pig or syngeneic thymus-grafted nude mice without AID. Thus, the decreased frequency, altered phenotype and functional deficiency of mouse CD4^＋CD25^＋ Treg cells in pig thymus-grafted nude mice may contribute to the development of AID in this model.     

Type 1 CD8^＋ T Cells are Superior to Type 2 CD8^＋ T Cells in Tumor Immunotherapy due to Their Efficient Cytotoxicity, Prolonged Survival and Type 1 Immune Modulation

CD8^＋ cytotoxic T （Tc） cells play a crucial role in host immune responses to cancer, and in this context, adoptive CD8^＋ Tc cell therapy has been studied in numerous animal tumor models. Its antitumor efficacy is, to a large extent, determined by the ability of Tc cells to survive and infiltrate tumors. In clinical trials, such in vitro-activated T cells often die within hours to days, and this greatly limits their therapeutic efficacy. CD8^＋ Tc cells fall into two subpopulations based upon their differential cytokine secretion. In this study, we in vitro generated that ovalbumin （OVA）-pulsed dendritic cell （DCovA）-activated CD8^＋ type 1 Tc （Tcl） cells secreting IFN-T, and CD8^＋ type 2 Tc （Tc2） cells secreting IL-4, IL-5 and IL-10, which were derived from OVA-specific T cell receptor （TCR） transgenic OT I mice. We then systemically investigated the in vitro and in vivo effector function and survival of Tcl and Tc2 cells, and then assessed their survival kinetics after adoptively transferred into C57BL/6 mice, respectively. We demonstrated that, when compared to CD8^＋ Tc2, Tcl cells were significantly more effective in perforin-mediated cytotoxicity to tumor cells, had a significantly higher capacity for in vivo survival after the adoptive T cell transfer, and had a significantly stronger therapeutic effect on eradication of well-established tumors expressing OVA in animal models. In addition, CD8^＋ Tcl and Tc2 cells skewed the phenotype of CD4^＋ T cells toward Thl and Th2 type, respectively. Therefore, the information regarding the differential effector function, survival and immune modulation of CD8^＋ Tcl and Tc2 cells may provide useful information when preparing in vitro DC-activated CD8^＋ T cells for adoptive T cell therapy of cancer.     

A naturally occurring CD8^＋CD122^＋ T-cell subset as a memory-like Treg family

Despite extensive studies on CD4^＋CD25^＋ regulatory T cells （Tregs） during the past decade, the progress on their clinical translation remains stagnant. Mounting evidence suggests that naturally occurring CD8^＋CD122^＋ T cells are also Tregs with the capacity to inhibit T-cell responses and suppress autoimmunity as well as alloimmunity. In fact, they are memory-like Tregs that resemble a central memory T cell （TcM） phenotype. The mechanisms underlying their suppression are still not well understood, although they may include IL-IO production. We have recently demonstrated that programmed death-1 （PD-1） expression distinguishes between regulatory and memory CD8^＋CD122^＋ T cells and that CD8^＋CD122^＋ Tregs undergo faster homeostatic proliferation and are more potent in the suppression of allograft rejection than conventional CD4^＋CD25^＋ Tregs. These findings may open a new line of investigation for accelerating effective Treg therapies in the clinic. In this review, we summarize the significant progress in this promising field of CD8^＋CD122^＋ Treg research and discuss their phenotypes, suppressive roles in autoimmunity and alloimmunity, functional requirements, mechanisms of action and potential applications in the clinic.     

The ex vivo Microenviroments in MLTC of Poorly Immunogenic Tumor Cells Facilitate Polarization of CD4^＋ CD25^＋ Regulatory T Cells

CD4^＋CD25^＋ regulatory T （TR） cells play an important role in maintaining a balanced peripheral immune system. Recent studies have shown that TR cells may also play a key role in suppressing anti-tumor immune response. In order to investigate the tumor immune microenvironment and its influence on TR polarization, poorly immunogenic tumor cell line Ds （C57BL/6, H-2^b）, immunogenic tumor cell lines FBL3 （C57BL/6, H-2^b） and H22 BALB/c, H-2^d） were used to establish the syngeneic/allogeneic, poorly immunogenic/immunogenic mixed lymphocytes-tumor cell culture （MLTC）. Our results revealed that the proportion of CD4^＋CD25^＋ T cells in MLTC of syngeneic primed splenocytes stimulated with D5 tumor cells was higher than that with H22 cells （0.43% vs 0.044%, and the similar results appeared in allogeneic splenocytes stimulated with D5 tumor cells （0.39% vs 0.04%）. The splenocytes stimulated with supernatant from syngeneic MLTC of D5 tumor cells demonstrated higher proportion of CD4^＋CD25^＋ cells than that from allogeneic MLTC of D5 tumor cells, and the splenocytes stimulated with supernatant from syngeneic or allogeneic MLTC of H22 tumor cells generated lower proportion of CD4^＋CD25^＋ T cells than that of D5 tumor cells. The TGF-β1 and Th2-oriented cytokines （IL-4 and IL-10） were dominated in supernatants of syngeneic MLTC of poorly immunogenic tumor cells. Our results provided useful information for studying the mechanisms underlying tumor immune surveillance as well as for the tumor immunotherapy.     

Immunotherapeutical Potential of Mycobacterium Vaccae on M. Tuberculosis Infection in Mice

Tuberculosis remains the worldwide infectious disease. To identify the therapeutic potential of M. vaccae in treating tuberculosis, M. vaccae was injected into Mycobacterium tuberculosis （M. tuberculosis） infected mice. The optimal dose of M. vaccae （22.5 μg/mouse） treated mice showed lower pathological change index, spleen weight index, lung weight index and vital M. tuberculosis count than those of the untreated group. Treatment with M. vaccae enhanced the percentages of CD3^＋ and CD4^＋ T cells, IFN-γ^＋CD4^＋ T cells, innate immune cells including NK cells, NK1.1^＋ T cells and γδ T cells, and reduced the percentage of IL-4^＋CD4^＋ T cells. Therefore, M. vaccae could protect the mice from M. tuberculosis infection and improved mouse innate and adaptive cell-mediated immunity, suggesting that M. vaccae is a potential immunotherapeutic agent in pulmonary tuberculosis. Cellular ＆ Molecular Immunology.     

Effect of protein kinase C on proliferation and apoptosis of T lymphocytes in idiopathic thrombocytopenic purpura children

It is well-documented that T lymphocyte proliferation and apoptosis are abnormal in idiopathic thrombocytopenic purpura （ITP） children. However, the underlying regulation mechanisms especially in terms of signal transduction remain unknown. In this paper, we reported the changes of protein kinase C （PKC） activity in peripheral blood T lymphocytes and the effect of PKC on T lymphocyte proliferation and apoptosis. We demonstrated that in ITP children, the activator （PMA） and inhibitor （H-7） of PKC affected on T lymphocyte proliferation and apoptosis dramatically, but they altered little in healthy children. PKC activity was significantly enhanced in ITP children together with an increased expression of FasL on CD3^＋ T, CD4^＋T and CD8^＋T cells, resulting in a positive correlation between PKC activity and the expression of FasL on T cells. While the PKC activity and the platelet count were negatively correlated. Taken together, our findings suggest that the PKC activation may enhance T lymphocytes activity, suppress T cell apoptosis and be involve in thrombocytes damage as a mechanism related to immune pathogenesis of ITP. Cellular ＆ Molecular Immunology. 2005; 2（3）： 197-203.     

IL-10-producing type 1 regulatory T cells and allergy

As an important subset of regulatory T （Treg） cells, IL-10-producing type 1 regulatory T cells （Trl）, have some different features to thymic-derived naturally occurring CD4^＋CD25^＋Foxp3^＋ Treg cells（nTreg cells）. Similar to nTreg cells, Trl also play important roles in the control of allergic inflammation in several ways. There is a fine balance between Trl and Th2 responses in healthy subjects. Skewing of allergic-specific effctor T cells to a Trl phenotype appears to be a critical event in successful allergen-specific immunotherapy and glucocorticoids and β2-agonists treatment. Trl suppress Th2 cells and effector cells of allergic inflammation, such as eosinophils, mast cells, basophils, through producing IL-10, and perhaps TGF-β. Understanding of Trl may be helpful in developing new strategies for treatment of allergic diseases.     

EBV-Induced Human CD8^＋ NKT Cells Synergise CD4^＋ NKT Cells Suppressing EBV-Associated Tumours upon Induction of Thl-Bias

CD8^＋ natural killer T （NKT） cells from EBV-associated tumour patients are quantitatively and functionally impaired. EBV-induced CD8^＋ NKT cells drive syngeneic T cells into a Thl-bias response to suppress EBV-associated malignancies. IL-4-biased CD4^＋ NKT cells do not affect either syngeneic T cell cytotoxicity or Th cytokine secretion. Circulating mDC1 cells from patients with EBV-associated malignancies impair the production of IFN-T by CD8^＋ NKT cells. In this study, we have established a human-thymus-SCID chimaera model to further investigate the underlying mechanism of EBV-induced CD8^＋ NKT cells in suppressing EBV-associated malignancies. In the human-thymus-SCID chimera, EBV-induced CD8^＋ NKT cells suppress EBV-associated malignancies in a manner dependent on the Thl-bias response and syngeneic CD3^＋ T cells. However, adoptive transfer with CD4^＋ NKT cells alone inhibits T cell immunity. Interestingly, CD4^＋ NKT cells themselves secrete high levels of IL-2, enhancing the persistence of adoptively transferred CD8^＋ NKT cells and T cells, thereby leading to a more pronounced T cell anti-tumour response in chimaeras co-transferred with CD4^＋ and CD8^＋ NKT cells. Thus, immune reconstitution with EBV-induced CD4^＋ and CD8^＋ NKT cells synergistically enhances T cell tumour immunity, providing a potential prophylactic and therapeutic treatment for EBV-associated malignancies.     

Cell-mediated immunity imbalance in patients with intrahepatic cholestasis of pregnancy

Decidual lymphocytes may mediate fetal trophoblast recognition and regulate maternal immune reaction and play an essential role in the maintenance of normal pregnancy. The aim of this study was to compare the percentage of T cells, natural killer （NK） cells and natural killer T （NKT） cells within decidual parietalis of normal pregnant controls （NP） and patients with intraheptic cholestasis of pregnancy （ICP）, and to investigate the production of interleukin-4 （IL-4）, interferon-γ （IFN-γ） in the culture supernatant of decidual parietalis mononuclear cells （DPMCs）. Compared with controls, the decidua parietalis from ICP were characterized with significant increased percentages of CD3^＋CD56^＋ cells, CD3^＋CD56^＋ cells, CD56^＋CD16＋ cells, CD56^＋CD16^＋ cells, CD56^＋NKG2D＋ ceils, and the significant decreased percentages of CD3^＋ cells, CD3^＋CD4^＋ cells. There were no differences found for the percentage of CD3^＋CD8^＋ cells, CD56^＋NKG2A^＋ cells between control and study group. In addition, the enhanced concentration of IFN-γ was presented in culture supernatant of DPMCs from ICP. It was suggested that the increased NK cells, NKT cells and the decreased T cells in the decidual parietalis and over-secretion of IFN-γ could be correlated with the pathophysiology of ICP patients. Cellular ＆ Molecular Immunology. 2007;4（1）：71-75.     

Blockade of Tim-3 Pathway Ameliorates Interferon-γ Production from Hepatic CD8^＋ T Cells in a Mouse Model of Hepatitis B Virus Infection

T cell immunoglobulin- and mucin-domain-containing molecule-3 （Tim-3） has been reported to participate in the pathogenesis of inflammatory diseases. However, whether Tim-3 is involved in hepatitis B virus （HBV） infection remains unknown. Here, we studied the expression and function of Tim-3 in a hydrodynamics-based mouse model of HBV infection. A significant increase of Tim-3 expression on hepatic T lymphocytes, especially on CD8^＋ T cells, was demonstrated in HBV model mice from day 7 to day 18. After Tim-3 knockdown by specific shRNAs, significantly increased IFN-γ production from hepatic CD8^＋ T cells in HBV model mice was observed. Very interestingly, we found Tim-3 expression on CD8^＋ T cells was higher in HBV model mice with higher serum anti-HBs production. Moreover, Tim-3 knockdown influenced anti-HBs production in vivo. Collectively, our data suggested that Tim-3 might act as a potent regulator of antiviral T-cell responses in HBV infection. Cellular ＆ Molecular Immunology.     

Thymic Nurse Cells Support CD4^-CD8^＋ Thymocytes to Differentiate into CD4^＋CD8^＋ Cells

Thymic nurse cells （TNCs） represent a unique microenvironment in the thymus for T cell maturation. In order to investigate the role of thymic nurse cells during T cell differentiation, a TNC clone, RWTE-1, which formed a typical complex with fetal thymocytes in vitro was established from normal Wistar rat. Hanging drop culture method was applied to reveal the interaction between TNCs and thymocytes. Our result revealed that eighty percent of immature CD4^-CD8^＋ cells differentiated into CD4^＋CD8^＋ cells after a 12-hour hanging drop culture with RWTE-1. However, in a 12-hour culture of immature CD4^-CD8^＋ cells with or without RWTE-1 supernatant, only 30% of the cells differentiated into CD4^＋CD8^＋ cells spontaneously. This observation led to the conclusion that RWTE-1 cell has the capacity to facilitate immature CD4^-CD8^＋ thymocytes to differentiate into CD4^＋CD8^＋ T cells by direct interaction.     

Naturally Occurring Self-Reactive CD4^＋CD25^＋ Regulatory T Cells： Universal Immune Code

Naturally occurring thymus-arisen CD4^＋CD25^＋ regulatory T （Treg） cells are considered to play a central role in self-tolerance. Precise signals that promote the development of Treg cells remain elusive, but considerable evidence suggests that costimulatory molecules, cytokines, the nature of the TCR and the niche or the context in which the T cell encounters antigen in the thymus play important roles. Analysis of TCR from Treg cells has demonstrated that a large proportion of this population has a higher avidity to self-antigen in comparison with TCR from CD4^＋CD25^＋ cells and that peripheral antigen is required for their development, maintenance, or expansion. Treg cells have been shown to undergo expansion in the periphery, likely regulated by the presence of self-antigen. Many studies have shown that the involvement of Treg cells in the tolerance induction is antigen-specific, even with MHC-mismatched, in transplantation/graft versus host disease （GVHD）, autoimmunity, cancer, and pregnancy. Theses studies concluded a vital role for self-reactive Treg cells in maintenance of the body integrity. Based on those studies, we hypothesize that self-reactive Treg cells are shared among all healthy individuals and recognize same self-antigens and their TCR encodes for few dominant antigens of each organ which defines the healthy self. These dominant self antigens can be regarded as ＂universal immune code＂. Cellular ＆ Molecular Immunology.     

The current immune function of hepatic dendritic cells

While only a small percentage of the liver as dendritic cells, they play a major role in the regulation of liver immunity. Four major types of dendritic cell subsets include myeloid CD8α^-B220^-, lymphoid CD8α^＋B220^-, plasmacytoid CD8α^-B220^＋, and natural killer dendritic cell with CD8α^-B220^-NK1.1^＋ phenotype. Although these subsets have slightly different characteristics, they are all poor naive T cell stimulators. In exchange for their reduced capacity for allostimulation, hepatic DCs are equipped with an enhanced ability to secrete cytokines in response to TLR stimulation. In addition, they have increased level of phagocytosis. Both of these traits suggest hepatic DC as part of the innate immune system. With such a high rate of exposure to the dietary and commensal antigens, it is important for the hepatic DCs to have an enhanced innate response while maintaining a tolerogenic state to avoid chronic inflammation. Only upon secondary infectivity does the hepatic DC activate memory T cells for rapid eradication of recurring pathogen. On the other hand, overly tolerogenic characteristics of hepatic DC may be responsible for the increase prevalence of autoimmunity or liver malignancies.     

Acquired pMHC I Complexes Greatly Enhance CD4＋ Th Cell＇s Stimulatory Effect on CD8＋T Cell-Mediated Diabetes in Transgenic RIP-mOVA Mice

CD4＋ helper T （Th） cells play pivotal roles in induction of CD8＋ CTL immunity. However, the mechanism of CD4＋ T cell help delivery to CD8＋ T cells in vivo is still elusive. In this study, we used ovalbumin （OVA）-pulsed dendritic cells （DCovA） to activate OT-II mouse CD4＋ T cells, and then studied the help effect of these CD4＋ T cells on CD8＋ cytotoxic T lymphocyte （CTL） responses＋ We also examined CTL mediated islet β cell destruction which leaded to diabetes in wild-type C57BL/6 mice and transgenic rat insulin promoter （RIP）-mOVA mice expressing β cell antigen OVA with self OVA-specific tolerance, respectively. In adoptive transfer experiments, we demonstrated that help, in the form of peptide/major histocompatibility complex （pMHC） I acquired from DCovA by DCovA activation, was required for induction of OVA-specific CTL responses in C57BL/6 mice. However, in combination ＋ ＋ ＋ with TCR transgenlc OT-I mouse CD8 T ceils, the tolerogenic dosage of CD4＋ Th cells with acquired pMHC I, but not CD4＋ （Kb-/-） Th cells without acquired pMHC I were able to cause diabetes in 8/10 （80%） RIP-mOVA mice. This study thus expands the current knowledge in T cell-mediated autoimmunity and provides insight into the nature of CD4＋ T cell-mediated help in CD8＋ CTL induction. Cellular ＆ Molecular Immunology. 2008;5（6）：407-415.     

Profiling the repertoire of T-cell receptor beta-chain variable genes in peripheral blood lymphocytes from subjects who have recovered from acute hepatitis B virus infection

The profile of T-cell receptor beta-chain variable （TRBV） genes usually skews in subjects with virus infection or cancer. The gene melting spectral pattern （GMSP） can be used to determine the profile of the TRBV gene family. To explore the portrait of the TRBV family in peripheral blood lymphocytes from subjects who have recovered from acute hepatitis B virus infection （AHI）, peripheral blood mononuclear cells （PBMCs） were separated and further sorted into CD4^＋ and CD8^＋ T-cell subsets. The molecular features of the TRBV complementary determining region 3 （CDR3） motifs were determined using GMSP analysis. When a GMSP profile showed a single peak, the monoclonally expanded TRBV gene was cloned and sequenced. Skewed expansions of multiple TRBV genes were observed among the CD4^＋ and CD8^＋ T-cell subsets and the PBMCs. The frequency of monoclonally expanded TRBV genes in the CD8^＋ T-cell subset was significantly higher than that of the CD4^＋ T-cell subset and the PBMCs. Compared to other members of the TRBV gene family, TRBV11, BV15 and BV20 were predominantly expressed in the repertoire of peripheral blood lymphocytes in recovered AHI subjects. The relatively conserved amino acid motifs of TRBV5.1 and BV20 CDR3 were also detected in the CD4^＋ and CD8^＋ T-cell subsets. These results demonstrate the presence of multiple biased TRBV families in recovered AHI subjects. TRBV11, BV15 and BV20, especially from the CD8＋ T-cell subset, may be relevant to the pathogenesis of subjects with AHh The preferentially selected TRBV5.1 and BV20 with the relatively conserved CDR3 motif may be potential targets for personalized treatments of chronic HBV infection.     

Intratumoral Expression of MIP-1β Induces Antitumor Responses in a Pre-Established Tumor Model through Chemoattracting T Cells and NK Cells

Direct intratumoral introduction of therapeutic or regulatory genes is a developing technology with potential application for cancer gene therapy. Macrophage inflammatory protein-1 beta (MIP-1β) is a chemokine which can chemoattract immune cells such as T cells. In the present study, murine colorectal adenocarcinoma CT26 cells were transfected with a recombinant adenovirus (AdhMIP-1β) carrying the human MIP-1β gene. 24h post-transfection, hMIP-1β levels reached approximately 980 pg/ml in supernatants of 10^6 hMIP-1β-transfected CT26 cells. Moreover, the supernatants exhibited chemotactic activity for CD8^ T cells, CD4^ T cells, NK cells and immature DCs. Intratumoral injection of AdhMIP-1β significantly inhibited tumor growth and prolonged the survival time of tumor-bearing mice. Intratumoral hMIP-1β gene transfer also induced powerful tumor-specific CTL responses in vivo. The therapeutic effects of hMIP-1β gene therapy were greatly reduced following in vivo depletion of both CD4^ and CD8~ T cells, but were unaffected by depletion of single T cell subsets. Immune cell depletion experiments also revealed that NK cells played an important role in hMIP-1β-induced antitumor responses. These results suggest that intratumoral expression of hMIP-1β has the potential effect to induce host antitumor immunity and may prove to be a useful form of cancer gene therapy.     

Isolation and identification of cancer stem-like cells from murine melanoma cell lines

In current study, cancer stem-like cells in the murine melanoma B16F10 cells were investigated. CD phenotypes of the B16F10 cells were analyzed by flow cytometry, and the specific CD phenotype cells from the B16F10 cells were isolated by MACS. Then we used colony formation assay in soft agar media, the cell growth assay in serum-free culture media as well as the tumorigenicity investigation of the specific CD phenotype cells in C57BL/6 mice, respectively, to identify cancer stem-like cells in the B16F10 cells. The results showed that the B16F10 cells could form spherical clones in serum-free culture media, and the rate of clonegenesis of CD133^＋, CD44^＋ and CD44^＋CD133^＋ cells was higher than that of CD133^-, CD44^- and CD44^＋CD133^＋ cells in soft agar media, respectively. The tumorigenic potential of CD133^＋, CD44^＋, CD44^＋CD133^＋ cells and CD44^＋CD133^＋CD24^＋ cells was stronger than that of CD133^-, CD44^-, CD44^＋CD133^- cells and CD44^＋CD133^＋CD24^- cells in mice, respectively. In conclusion, the CD44^＋CD133^＋CD24^＋ cells have some biological properties of cancer stem-like cells or are highly similar to the characteristics of cancer stem cells （CSC）. These results provide an important method for identifying cancer stem-like cells in B16F10 cells and for further cancer target therapy. Cellular ＆ Molecular Immunology.