A novel trivalent non-Fc anti-CD3 Collabody preferentially induces Th1 cell apoptosis in vitro and long-lasting remission in recent-onset diabetic NOD mice

Specific anti-CD3 treatment is deemed to be a promising therapy for allograft rejection and type 1 diabetes (T1D). Fc receptor (FcR) reduced-binding antibodies, by avoiding adverse effects of Fc and FcR interaction, have good therapeutic potential. We generated a trivalent anti-mouse-CD3 Collabody, h145CSA, by using a triplex-forming collagen-like peptide (Gly-Pro-Pro)10 to drive the trimerization of the Fab fragments. Exposure to h145CSA, but not its bivalent counterparts 145-2C11 and h145chIgGAA (FcR reduced-binding format), upregulates FasL expression on Th1 cells and causes Th1 cell apoptosis. Administration of h145CSA invokes minimal mitogenic effects in mice. The ability of multiple dosing of h145CSA to induce splenic CD4+ T-cell depletion is comparable to bivalent antibodies but is characterized by more rapid CD4+ T-cell recovery kinetics. h145CSA is more potent than h145chIgGAA in inducing long-lasting remission in recent-onset diabetic NOD mice. Its therapeutic effect is accompanied by a significantly lower percentage of CD4+IFNγ+ T cells and a higher Treg/Th1 ratio in pancreatic and mesenteric lymph nodes. The results of our study demonstrate that trivalent non-Fc anti-CD3 Collabody has the potential to be used in the treatment of T1D.

CD8+ T cell memory is sustained in mice by hepatic stellate cells

BACKGROUND AND AIMS

Long-lasting immunological memory is the ultimate goal of vaccination. Homeostatic maintenance of memory CD8⁺ cytotoxic T cells (MemCD8TCs) is thought to be mediated by IL-15/IL-15R heterodimer (15HD)-expressing myeloid cells. Nonmyeloid hepatic stellate cells (HSCs) also express 15HD, but their role in maintaining MemCD8TC homeostasis is unknown.

APPROACH AND RESULTS

We engineered a genetically engineered mouse in which IL-15R complementary DNA (cDNA) had been inserted in-frame with lecithin-retinol acyltransferase gene and bred onto an IL-15R-KO (15R-KO) genetic background (L15R) that expressed IL-15R in HSCs at normal levels, but not in other liver cells. Outside of the liver of L15R mice, IL-15R expression was found in a number of organs, but not in dendritic cells and macrophages. The low IL-15R expression in the bone marrow (BM) of L15R mice was eliminated by the reconstitution of lethally-irradiated L15R mice with 15R-KO BM to generate L15RC mice. Because MemCD8TC maintenance is mediated by 15HD, not empty IL-15R, 15HD content in L15R mice was determined and found for liver, lung, kidney, and heart. L15R and L15RC mice developed and maintained long-lasting, systemic antigen-specific MemCD8TCs that were efficacious against tumor growth and Listeria monocytogenes infection in an antigen-specific manner. Among the four organs with 15HD content, liver-associated MemCD8TCs were different from those found in the lung, kidney, and heart in two ways: (1) they were quantitatively the most numerous, and (2) they appeared uniquely in the form of clusters in a specialized structure, sinusoidal niches of the liver.

CONCLUSIONS

The liver, the largest organ of the body, is endowed with the capability of effectuating long-lasting functional cytotoxic T cell memory.

CD28 engagement inhibits CD73-mediated regulatory activity of CD8+ T cells

CD28 is required for T cell activation as well as the generation of CD4⁺Foxp3⁺ Treg. It is unclear, however, how CD28 costimulation affects the development of CD8⁺ T cell suppressive function. Here, by use of Hepa1.6.gp33 in vitro killing assay and B16.gp33 tumor mouse model we demonstrate that CD28 engagement during TCR ligation prevents CD8⁺ T cells from becoming suppressive. Interestingly, our results showed that ectonucleotidase CD73 expression on CD8⁺ T cells is upregulated in the absence of CD28 costimulation. In both murine and human tumor-bearing hosts, CD73 is upregulated on CD28^-CD8⁺ T cells that infiltrate the solid tumor. UPLC-MS/MS analysis revealed that CD8⁺ T cells activation without CD28 costimulation produces elevated levels of adenosine and that CD73 mediates its production. Adenosine receptor antagonists block CD73-mediated suppression. Our data support the notion that CD28 costimulation inhibits CD73 upregulation and thereby prevents CD8⁺ T cells from becoming suppressive. This study uncovers a previously unidentified role for CD28 costimulation in CD8⁺ T cell activation and suggests that the CD28 costimulatory pathway can be a potential target for cancer immunotherapy.

Rapid Death of Follicular B Cells and Burkitt Lymphoma Cells Effectuated by Xbp1s

BCR-mediated tonic signaling is an indispensable requirement for the survival of follicular B (FOB) cells and Burkitt lymphoma (BL) cells. FOB cells of the I-A^12% mutant mouse express unfolded protein response and are extremely short lived. Among the myriad molecules activated by unfolded protein response in I-A^12% B cells, Xbp1s singularly "hijacked" p110 from p85:p110 heterodimeric PI3K, thereby abating BCR tonic signaling, resulting in their extremely short lifespan. Long-lived normal FOB cells became short lived upon ectopic Xbp1s expression. The proapoptotic Xbp1s role in FOB cells starkly contrasts with its antithetical prosurvival function in plasma cells. Also, tonic signaling and clonal expansion, two important functions mediated by the same BCR, operate in independent and distinct manners. Furthermore, concerning the development of new therapeutic treatment of drug-refractory BL patients, our finding of Xbp1s-mediated rapid death of BL cells brings forth a conceptual advancement based on blocking PI3K heterodimer formation rather than inhibition of PI3K enzyme activity.

ENU-induced C-terminal truncation of Runx3 results in Th17-associated autoimmune colitis

Inflammatory bowel disease (IBD) is a common, chronic, progressive inflammatory intestinal disease in the world. The etiology of IBD is due to the imbalance of host immune responses to intestinal flora. Many human genes play the important role to induce improper immune responses, including IL-10, STAT3, IRGM, AGT16L1, NOD2 and RUNX3. It has been reported that homozygous Runx3-ko mice develop colitis spontaneously. However, homozygous Runx3-ko mice show very high mortality rate in the first 2 week of life, and are hard to study the role of Runx3 in the spontaneous colitis. A mouse pedigree (spontaneous colitis, SC) carried an ENU-induced Tyr301stop point mutation of Runx3, which resulted in a short form truncated form of Runx3. SC mice started to show spontaneous diarrhea after weaning. SC mice exhibited prominant enlargement of colon that revealed large amounts of inflammatory cells infiltration from mucosal to muscular layers. Immunofluorescent staining showed large amounts of CD4+ T cells involved in the inflammatory colon. Moreover, inflammatory colons of SC mice expressed higher mRNA levels of IL-17A, and serum IL-17A level were also upregulated in SC mice. In addition, SC CD4+ T cells expressed stronger IL-17A than WT CD4+ T cells after in vitro activation. Transfer of total SC CD4+ T cells into Rag1-ko host mice resulted in autoimmune colitis. In summary, C-terminal truncated Runx3 results in autoimmune colitis through elevated Th17 immune responses. Thus, the SC mouse model is a valuable tool for investigations on the effect of immune system upon spontaneous colitis.

ENU-induced C-terminal truncation of Runx3 in mice enhances maintenance of memory T cells through upregulation of IL-15 expression

Immunological memory provides faster and stronger immune responses to protect host from infectious pathogens and tumor cells. T cell memory is a major part of immunological memory, and plays an important role to eliminate tumor cells or cells infected by intracellular pathogen. Cytokines including IL-15, IL-7 and IL-4 have been reported to enhance the generation or maintenance of memory T cells. IL-15 enhances homeostatic proliferation and survival of memory CD8+ T cells. An ENU-affected mouse pedigree carried a Tyr301stop point mutation of Runx3, which resulted in a truncated form of Runx3. These mice started to show spontaneous diarrhea after weaning (spontaneous colitis, SC). SC mice also expressed CD4-derepression in the CD8+ T cells, and loss of memory phenotype CD8+ T cells. SC CD8+ T cells showed proliferation deficiency and decreased memory CD8+ T cell precursors after activation and also had poor response to IL-15-induced proliferation. However, SC host mice enhanced in vivo long-term survival of activated WT CD8+ cells through improvement of homeostatic proliferation. This improvement of homeostatic proliferation was due to elevated serum IL-15 levels. In summary, C-terminal truncated Runx3 in mice results in upregulation of IL-15 expression and provides enhanced homeostatic environment for memory CD8+ T cells; however, CD8+ T cells have intrinsic memory defect. Thus, the SC mouse model is a valuable tool for investigations on the effect of immune system upon spontaneous colitis.

STAT1 regulates marginal zone B cell differentiation in response to inflammation and infection with blood-borne bacteria

Chen et al. show that STAT1 positively regulates TLR- and S. pneumoniae–induced IgM responses of MZ B cells through up-regulation of Prdm1 expression, and STAT1 is crucial for MZ B cell–mediated clearance of blood-borne S. pneumoniae infection.

Marginal zone B (MZ B) cells can rapidly produce antibody in response to infection with blood-borne encapsulated pathogens. Although TLR-mediated activation of MZ B is known to trigger humoral immune response, the signal cascade directing this response remains undefined. Here, we demonstrate that STAT1 plays an essential role in TLR-mediated antibody response of MZ B cells. Further, the TLR-induced IgM response is impaired in a type I and type II IFN-independent manner. Although activation, proliferation, and apoptosis are not affected, both differentiation into plasma cells and IgM production are impaired in Stat1^−/− MZ B cells. Interestingly, STAT1 directly regulates the expression of Prdm1 (encodes BLIMP-1) by binding to its promoter, and Prdm1 expression is reduced in Stat1^−/− MZ B cells. Restoration of BLIMP-1 to cells rescues TLR-induced IgM response. Moreover, Stat1^−/− mice are more susceptible to S. pneumoniae infection, which can be rescued by the serum of bacteria-primed WT mice. The increased susceptibility to S. pneumoniae infection in Stat1^−/− mice is also intrinsic to STAT1 requirement in MZ B cells. Collectively, these results define a differential regulation of TLR-mediated activation and differentiation of MZ B cells by STAT1 and reveal a STAT1-dependent, but IFN-independent, antibody response during infection and inflammation.

LPS receptor subunits have antagonistic roles in epithelial apoptosis and colonic carcinogenesis

Colorectal carcinoma (CRC) is characterized by unlimited proliferation and suppression of apoptosis, selective advantages for tumor survival, and chemoresistance. Lipopolysaccharide (LPS) signaling is involved in both epithelial homeostasis and tumorigenesis, but the relative roles had by LPS receptor subunits CD14 and Toll-like receptor 4 (TLR4) are poorly understood. Our study showed that normal human colonocytes were CD14(+)TLR4(-), whereas cancerous tissues were CD14(+)TLR4(+), by immunofluorescent staining. Using a chemical-induced CRC model, increased epithelial apoptosis and decreased tumor multiplicity and sizes were observed in TLR4-mutant mice compared with wild-type (WT) mice with CD14(+)TLR4(+) colonocytes. WT mice intracolonically administered a TLR4 antagonist displayed tumor reduction associated with enhanced apoptosis in cancerous tissues. Mucosa-associated LPS content was elevated in response to CRC induction. Epithelial apoptosis induced by LPS hypersensitivity in TLR4-mutant mice was prevented by intracolonic administration of neutralizing anti-CD14. Moreover, LPS-induced apoptosis was observed in primary colonic organoid cultures derived from TLR4 mutant but not WT murine crypts. Gene silencing of TLR4 increased cell apoptosis in WT organoids, whereas knockdown of CD14 ablated cell death in TLR4-mutant organoids. In vitro studies showed that LPS challenge caused apoptosis in Caco-2 cells (CD14(+)TLR4(-)) in a CD14-, phosphatidylcholine-specific phospholipase C-, sphingomyelinase-, and protein kinase C-ζ-dependent manner. Conversely, expression of functional but not mutant TLR4 (Asp299Gly, Thr399Ile, and Pro714His) rescued cells from LPS/CD14-induced apoptosis. In summary, CD14-mediated lipid signaling induced epithelial apoptosis, whereas TLR4 antagonistically promoted cell survival and cancer development. Our findings indicate that dysfunction in the CD14/TLR4 antagonism may contribute to normal epithelial transition to carcinogenesis, and provide novel strategies for intervention against colorectal cancer.

Marginal zone B cell is a major source of Il-10 in Listeria monocytogenes susceptibility

Rag-1-knockout (KO) mice are highly resistant to Listeria monocytogenes infection. The role played by the many Rag-1-dependent lymphocyte lineages was studied using a genetic approach in which each Rag-1-dependent lymphocyte lineage was eliminated one at a time. Only B cell-deficient Igh-KO mice displayed reduced bacterial load and improved survival upon Listeria infection. Listeria infection of Rag-1-KO and Il-10-KO hosts that had been adoptively transferred with wild-type marginal zone B (MZB) cells, but not follicular B cells, resulted in heightened bacterial load and increased Il-10 production in the spleen, but not the liver. This MZB cell-dependent increase in bacterial load was eliminated by anti-Il-10 mAb. In addition, Listeria infection of MZB cell-deficient Rbpj-cKO mice showed decreased bacterial load and increased survival. Whereas multiple cell types have been shown to be capable of Il-10 production, our results indicate that the MZB cell is the most dominant and relevant Il-10 source in the context of Listeria susceptibility. In marked contrast to the generally protective nature of MZB cells in defending against pathogenic infection, our results demonstrate that MZB cells play a detrimental role in Listeria infection and possibly other infections as well.

The Biology of Autoimmune Response in the Scurfy Mice that Lack the CD4+Foxp3+ Regulatory T-Cells

Due to a mutation in the Foxp3 transcription factor, Scurfy mice lack regulatory T-cells that maintain self-tolerance of the immune system. They develop multi-organ inflammation (MOI) and die around four weeks old. The affected organs are skin, tail, lungs and liver. In humans, endocrine and gastrointestinal inflammation are also observed, hence the disease is termed IPEX (Immunodysregulation, Polyendocrinopathy, Enteropathy, X-linked) syndrome. The three week period of fatal MOI offers a useful autoimmune model in which the controls by genetics, T-cell subsets, cytokines, and effector mechanisms could be efficiently investigated. In this report, we will review published work, summarize our recent studies of Scurfy double mutants lacking specific autoimmune-related genes, discuss the cellular and cytokine controls by these genes on MOI, the organ-specificities of the MOI controlled by environments, and the effector mechanisms regulated by specific Th cytokines, including several newly identified control mechanisms for organ-specific autoimmune response.

Effector function-deficient memory CD8+ T cells clonally expand in the liver and give rise to peripheral memory CD8+ T cells

Upon adoptive transfer into histocompatible mice, naive CD8(+) T cells stimulated ex vivo by TCR+IL-4 turn into long-lived functional memory cells. The liver contains a large number of so formed memory CD8(+) T cells, referred to as liver memory T cells (T(lm)) in the form of cell clusters. The CD62L(low) expression and nonlymphoid tissue distribution of T(lm) cells are similar to effector memory (T(em)) cells, yet their deficient cytotoxicity and IFN-γ inducibility are unlike T(em) cells. Adoptive transfer of admixtures of TCR+IL-4-activated Vβ8(+) and Vβ5(+) CD8(+) T cells into congenic hosts reveals T(lm) clusters that are composed of all Vβ5(+) or Vβ8(+), not mixed Vβ5(+)/Vβ8(+) cells, indicating that T(lm) clusters are formed by clonal expansion. Clonally expanded CD8(+) T cell clusters are also seen in the liver of Listeria monocytogenes-immune mice. T(lm) clusters closely associate with hepatic stellate cells and their formation is IL-15/IL-15R-dependent. CD62L(low) T(LM) cells can home to the liver and secondary lymphoid tissues, remain CD62L(low), or acquire central memory (T(cm))-characteristic CD62L(hi) expression. Our findings show the liver as a major site of CD8(+) memory T cell growth and that T(lm) cells contribute to the pool of peripheral memory cells. These previously unappreciated T(lm) characteristics indicate the inadequacy of the current T(em)/T(cm) classification scheme and help ongoing efforts aimed at establishing a unifying memory T cell development pathway. Lastly, our finding of T(lm) clusters suggests caution against interpreting focal lymphocyte infiltration in clinical settings as pathology and not normal physiology.

Identification through ENU genome-wide mutagenesis of a novel mutant mouse that expresses a non-functional induced T cell kinase (Itk) with 8-amino acid insertion (33.30)

With the human genome sequenced, the race is on to understand the functions of the 30,000 or so genes. Ethyl-nitrosourea (ENU) was used to treat C57BL/6 (B6) male mice, followed by a 3-generation breeding scheme to generate G3 mice that were screened for immunological phenotypes under recessive genetic control. The primary phenotypes of one mutant, P-135, were increased CD44hi representation among both CD4 and CD8 T cells and highly elevated serum IgE. Recessive mode of inheritance was confirmed by mating an affected G3 male to wildtype B6 females to generate F2 offspring. Affected G3 mice were outcrossed to generated F2 offspring and the affected F2 mice were subjected to linkage analysis by haplotype interval mapping (Neuhaus and Beier, 1998. Mammalian Genome 9, 150-154). The mutant gene was found to be linked to chromosome 11. Through DNA sequencing of genes located within the linked region, a point mutation (T to C) in the 12th intron was identified. This point mutation resulted in the creation of a new splice donor site which in turn resulted in a 24-bp (8 amino acids, RVRAGMCR) in-frame insertion. P-135 mutant mice thus carries a non-functional Itk protein with 8 amino acid insertion and may be useful in defining structural-functional relationships of Itk.

Rapid and selective expansion of nonclonotypic T cells in regulatory T cell-deficient, foreign antigen-specific TCR-transgenic scurfy mice: antigen-dependent expansion and TCR analysis

Foreign Ag-specific TCR-transgenic (Tg) mice contain a small fraction of T cells bearing the endogenous Vbeta and Valpha chains as well as a population expressing an intermediate level of Tg TCR. Importantly, these minor nonclonotypic populations contain > or = 99% of the CD4(+)Foxp3(+) regulatory T cells (Treg) and, despite low overall Treg expression, peripheral tolerance is maintained. In the OT-II TCR (OVA-specific, Vbeta5(high)Valpha2(high)) Tg scurfy (Sf) mice (OT-II Sf) that lack Treg, nonclonotypic T cells markedly expanded in the periphery but not in the thymus. Expanded T cells expressed memory/effector phenotype and were enriched in blood and inflamed lungs. In contrast, Vbeta5(high)Valpha2(high) clonotypic T cells were not expanded, displayed the naive phenotype, and found mainly in the lymph nodes. Importantly, Vbeta5(neg) T cells were able to transfer multiorgan inflammation in Rag1(-/-) recipients. T cells bearing dual TCR (dual Vbeta or dual Valpha) were demonstrated frequently in the Vbeta5(int) and Valpha2(int) populations. Our study demonstrated that in the absence of Treg, the lack of peripheral expansion of clonotypic T cells is due to the absence of its high-affinity Ag OVA. Thus, the rapid expansion of nonclonotypic T cells in OT-II Sf mice must require Ag (self and foreign) with sufficient affinity. Our study has implications with respect to the roles of Ag and dual TCR in the selection and regulation of Treg and Treg-controlled Ag-dependent T cell expansion in TCR Tg and TCR Tg Sf mice, respectively.

Pervasive and stochastic changes in the TCR repertoire of regulatory T-cell-deficient mice

We hypothesize that regulatory T-cell (Treg)-deficient strains have an altered TCR repertoire in part due to the expansion of autoimmune repertoire by self-antigen. We compared the Vbeta family expression profile between B6 and Treg-lacking B6.Cg-Foxp3(sf)(/Y) (B6.sf) mice using fluorescent anti-Vbeta mAbs and observed no changes. However, while the spectratypes of 20 Vbeta families among B6 mice were highly similar, the Vbeta family spectratypes of B6.sf mice were remarkably different from B6 mice and from each other. Significant spectratype changes in many Vbeta families were also observed in Treg-deficient IL-2 knockout (KO) and IL-2Ralpha KO mice. Such changes were not observed with anti-CD3 mAb-treated B6 mice or B6 CD4+CD25- T cells. TCR transgenic (OT-II.sf) mice displayed dramatic reduction of clonotypic TCR with concomitant increase in T cells bearing non-transgenic Vbeta and Valpha families, including T cells with dual receptors expressing reduced levels of transgenic Valpha and endogenous Valpha. Collectively, the data demonstrate that Treg deficiency allows polyclonal expansion of T cells in a stochastic manner, resulting in widespread changes in the TCR repertoire.

IL-4 inducibility in NKT cells, naïve CD4+ T cells and TCR-gamma delta T cells

NKT cells, naïve CD4(+) T cells, and TCR-gammadelta T cells belong to distinct T cell lineages but all express T cell receptors generated through random combinatorial joining of V-(D)-J genes. These distinct lineage T cells also possess the property of promptly activating the IL-4 gene upon T cell receptor stimulation. A comparative accounting of features as they pertain to IL-4 inducibility in these three distinct lineage T cells is provided here.

Identification of a mouse mutant with highly deficient cytotoxic T cell memory generation using ENU-induced genome-wide mutagenesis (85.7)

While much has been learned about CTL memory maintenance, much remains to be learned on the early events of CTL activation or induction phase. Through an ENU-induced genome-wide mouse mutagenesis program, we screened G3 mice using CD44 expression on CD8+ T cells as a surrogate indicator of the relative representation of the CTL memory subset. One such identified mutant (P-054) has highly deficient CD44hi subset within CD8+ T cells but normal CD44hi subset in CD4+ T cells. An affected male mouse was bred to normal females to generate F1 mice that all had normal numbers of CTL memory subset based on CD44 expression. Random intercross of F1 mice generated CTL deficienct F2 mice at a ratio of ~25%, indicating heritability of this trait and recessive transmission. Linkage of the mutant gene has been established to chromosome 4 to within a region of ~30 genes. The mutant mouse (H-2b) was immunized by BALB.B spleen cells (H-2b) and CTL memory T cells were identified by H60 (a BALB/c-encoded minor histocompatibility ag)-sepcific CTL by appropriate pentamers and a highly deficient H60-specific CTL response was seen. Adoptive transfer of 2C TCR tg CD8+ T cells activated in the presence of added IL-4, a condition known to promote strong CTL memory generation, into P-054 mice resulted in potent maintenance of 2C memory T cells. Thus, P-054 can provide an environment required to maintain known memory CD8+ T cells and likely represents a novel mutant model that is deficient in the induction phase of CTL memory generation.

Both virus and tumor necrosis factor alpha are critical for endothelium damage in a mouse model of dengue virus-induced hemorrhage

Hemorrhage is a common clinical manifestation in dengue patients. However, the pathogenic mechanism of dengue virus (DV)-induced hemorrhage awaits clarification. We established a mouse model of DV hemorrhage using immunocompetent C57BL/6 mice by injecting DV serotype 2 strain 16681 intradermally. While inoculation of 3 x 10(9) PFU of DV induced systemic hemorrhage in all of the mice by day 3 of infection, one out of three of those injected with 4 x 10(7) to 8 x 10(7) PFU developed hemorrhage in the subcutaneous tissues. The mice that were inoculated with 4 x 10(7) to 8 x 10(7) PFU but that did not develop hemorrhage were used as a basis for comparison to explore the pathogenic mechanism of dengue hemorrhage. The results showed that mice with severe thrombocytopenia manifested signs of vascular leakage and hemorrhage. We observed that high viral titer, macrophage infiltration, and tumor necrosis factor alpha (TNF-alpha) production in the local tissues are three important events that lead to hemorrhage. Immunofluorescence staining revealed that DV targeted both endothelial cells and macrophages. In addition, the production of high levels of TNF-alpha in tissues correlated with endothelial cell apoptosis and hemorrhage. By comparing TNF-alpha(-/-) to IgH(-/-), C5(-/-), and wild-type mice, we found that TNF-alpha was important for the development of hemorrhage. In vitro studies showed that mouse primary microvascular endothelial cells were susceptible to DV but that TNF-alpha enhanced DV-induced apoptosis. Our mouse model illustrated that intradermal inoculation of high titers of DV predisposes endothelial cells to be susceptible to TNF-alpha-induced cell death, which leads to endothelium damage and hemorrhage development. This finding highlights the contribution of the innate immune response to dengue hemorrhage.

The endogenous immune response modulates the course of IgA-immune complex mediated nephropathy

In animal models of IgA nephropathy, the inevitable endogenous immune response to passively administered antigens alone or in complex with specific IgA mask the exact role each might play in pathogenesis. To delineate the role the immune response might play, we have developed a passive model with exclusive IgA-immune complex-mediated nephropathy in B-cell-deficient (BCD) mice. Glomerular IgA immune deposits were induced by administration of purified IgA antiphosphorylcholine and the specific pneumococcal C-polysaccharide (PnC) antigen daily for 2 weeks into BCD and wild-type (WT) mice. In BCD mice IgA+PnC deposits induced severe glomerular injury and renal dysfunction. In contrast, WT mice developed intense glomerular IgG and IgM and C3 co-deposits of the IgA+PnC with significantly less renal injury. Cytofluorometric analysis revealed that PnC induced in BCD, but not in WT, a rapid and dramatic increase in number of activated CD3(+)/CD69(+) T-cell population. The nuclear factor-kappa B (NF-kappaB) transcription factor was activated early and progressively increased in response to glomerular IgA+PnC deposits. These results suggest that nephritogenic IgA+PnC immune deposits induce glomerular and renal dysfunction through activation of the NF-kappaB. This inflammatory pathway is modulated by the endogenous cellular and antibody response to the antigen affecting the course of IgA nephropathy progression.

CD1d-Independent Developmental Acquisition of Prompt IL-4 Gene Inducibility in Thymus CD161(NK1)−CD44lowCD4+CD8− T Cells Is Associated with Complementarity Determining Region 3-Diverse and Biased Vβ2/Vβ7/Vβ8/Vα3.2 T Cell Receptor Usage

Among Ag-inexperienced naive T cells, the CD1d-restricted NKT cell that uses invariant TCR-alpha-chain is the most widely studied cell capable of prompt IL-4 inducibility. We show in this study that thymus CD161-CD44lowCD4+CD8- T cells promptly produce IL-4 upon TCR stimulation, a response that displays biased Vbeta(2/7/8) and Valpha3.2 TCR usage. The association of Vbeta family bias and IL-4 inducibility in thymus CD161-CD44lowCD4+CD8- T cells is found for B6, B10, BALB/c, CBA, B10.A(4R), and ICR mouse strains. Despite reduced IL-4 inducibility, there is a similarly biased Vbeta(2/7/8) TCR usage by IL-4 inducibility+ spleen CD161-CD44lowCD4+CD8- T cells. Removal of alpha-galacotosylceramide/CD1d-binding cells from CD161-CD44lowCD4+CD8- thymocytes does not significantly affect their IL-4 inducibility. The development of thymus CD161-CD44lowCD4+CD8- T cells endowed with IL-4 inducibility and their associated use of Vbeta(2/7/8) are beta2-microglobulin-, CD1d-, and p59fyn-independent. Thymus CD161-CD44lowCD4+CD8- T cells produce low and no IFN-gamma inducibility in response to TCR stimulation and to IL-12 + IL-18, respectively, and they express diverse complementarity determining region 3 sequences for both TCR-alpha- and -beta-chains. Taken together, these results demonstrate the existence of a NKT cell distinct, TCR-repertoire diverse naive CD4+ T cell subset capable of prompt IL-4 inducibility. This subset has the potential to participate in immune response to a relatively large number of Ags. The more prevalent nature of this unique T cell subset in the thymus than the periphery implies roles it might play in intrathymic T cell development and may provide a framework upon which mechanisms of developmentally regulated IL-4 gene inducibility can be studied.

Immunopathogenic role of TH1 cells in autoimmune diabetes: Evidence from a T1 and T2 doubly transgenic non-obese diabetic mouse model

To improve the feasibility of in vivo monitoring of autoreactive T cells in the diabetogenic process, we generated T1 and T2 doubly transgenic non-obese diabetic (NOD) mice in which transgenic human CD90 (hCD90) is simultaneously expressed on IFN-gamma-producing cells or murine CD90.1 (mCD90.1) is expressed on IL-4-producing cells. These transgenic NOD mice develop diabetes with the same kinetics and incidence as wild type NOD mice, permitting the physiological characterization of CD4(+)hCD90(+) cells, which represent T(H)1 cells in lymphoid organs and at the site of insulitis. CD4(+)hCD90(+) cells had a higher capacity to secret IFN-gamma than CD4(+)hCD90(-) cells in an autoantigen-specific manner. Transgenic mice treated with GAD65 plasmid were protected from autoimmune diabetes, and had a lower number of CD4(+)hCD90(+) cells, confirming the pathogenic role of CD4(+)hCD90(+) cells in autoimmune diabetes. To further investigate the effect of IL-12 on the development of T(H)1 cells in autoimmune diabetes, we crossed these doubly transgenic mice to IL-12p35-deficient NOD mice. Despite severe disturbance of diabetes in p35(-/-) mice, the frequency of T(H)1 cells in these mice was slightly lower than in wild type mice. These data support the pathological role of IL-12 in autoimmune diabetes and suggest the existence an IL-12-independent pathway of T(H)1 development.

The combined effect of IL-4 and IL-10 suppresses the generation of, but does not change the polarity of, type-1 T cells in Histoplasma infection

Dominant type-1 cytokine production is induced in a murine model of systemic histoplasmosis. We used this model to investigate whether the presence of antagonistic cytokines during T cell priming changes the polarity of T cells in response to Histoplasma infection. Before infection with Histoplasma capsulatum, mice were injected twice with goat anti-mouse IgD antiserum (GalphaMdelta), which induced expression of dominant type-2 cytokines. At days 7 and 14 after infection, the GalphaMdelta-treated mice had suppressed IFN-gamma response and a significantly greater fungal burden in their spleens and lungs. The number of IFN-gamma-producing cells as well as the level of IFN-gamma produced per cell was greatly reduced. Not only CD4+ T cells but also CD8+ T cells were affected. The number of Histoplasma-induced IFN-gamma-producing cells was partially restored in GalphaMdelta-treated IL-4-/- and IL-10-/- mice and completely restored in IL-4-/- IL-10-/- mice. Thus, the combined effect of IL-4 and IL-10 suppressed the generation of IFN-gamma-producing cells. A longitudinal study demonstrated that as IL-4 and IL-10 decreased, the number of Histoplasma-induced IFN-gamma-producing cells rapidly increased, and fungal clearance improved, demonstrating that the presence of IL-4 and IL-10 did not permanently change the polarity of T cells.

Cytotoxic T lymphocytes generated by short-term in vitro TCR stimulation in the presence of IL-4 are therapeutically effective against B16 melanoma

P14 TCR transgenic CD8+ T cells (LCMV gp33-specific) were activated by antigen in the presence of either IL-2 or IL-2 + IL-4 to generate effector cytotoxic T lymphocytes (CTLs). The therapeutic effectiveness of such IL-2- or IL-2 + IL-4-grown CTLs was tested in mice that had received intravenous inoculations of B16.gp33 melanoma cells 7 days previously. Administration of P14 CTLs activated by antigen + IL-2 + IL-4 was significantly more effective at reducing melanoma colony formation in the lung than those grown in the presence of antigen + IL-2. Highly significant improvement in survival was observed with 80% of B16.gp33-inoculated mice showing long-term survival after therapy with 10 x 10(6) antigen + IL-2 + IL-4-activated P14 CTLs. Similar therapeutic effectiveness of antigen + IL-2 + IL-4-activated P14 CTLs against subcutaneously inoculated B16.gp33 melanoma cells was also found. There was significant reduction in P14 CD8+ T cells in the peripheral blood of B16.gp33-inoculated mice than in mice that did not receive B16.gp33 melanoma cells, indicating possible homing of P14 CD8+ T cells to the site of tumor growth or antigen-induced apoptotic cell death. These results may have implications in tumor therapy using CTLs grown ex vivo, especially during early stages of tumor formation. They also support the concept that the therapeutic effectiveness of CTLs can be governed by the cytokine context in which they are activated.

Anti-CD95-induced lethality requires radioresistant Fcgamma RII+ cells. A novel mechanism for fulminant hepatic failure

The Jo2 anti-mouse CD95 monoclonal antibody induces lethality in mice characterized by hepatocyte death and liver hemorrhage. Mice bearing a defect in Fas expression or in the Fas-mediated apoptotic pathway are resistant to Jo2. Here we show that FcgammaRII knockout mice or mice with monoclonal antibody-blocked FcgammaRII are also resistant to Jo2. The critical FcgammaRII(+) cells are radioresistant and could not be reconstituted with splenic cells. Death of sinusoidal lining cells and destruction of sinusoids were observed, consistent with the characteristic liver hemorrhage and the selective FcgammaRII expression in sinusoidal lining cells but not hepatocytes. Hemorrhage developed coincident with hepatocyte death and the sharp rise of serum alanine aminotransferase and alanine aminotransferase. Invariably, moribund mice showed severe liver hemorrhage and destruction of sinusoids. The data demonstrate a novel mechanism by which the destruction of liver sinusoids, induced by the Jo2-mediated co-engagement of Fas and FcgammaRII, leads to severe hemorrhage and lethal fulminant hepatitis.

The roles of interleukin-1 and interleukin-1 receptor antagonist in antigen-specific immune responses

Despite evidence that interleukin (IL)-1 promotes the proliferation of some T helper 2 (Th2) cell clones in vitro, the physiological role of IL-1 in the regulation of antigen-specific immune responses remains undefined. Using a liposome-DNA delivery system, we transiently expressed IL-1 receptor antagonist (IL-1Ra) to suppress IL-1 functions at the site of the antigen-specific primary immune response. Our data indicate, for the first time, that IL-1Ra downregulates antigen-specific IL-4 and IgE responses, with concomitant enhancement of interferon-gamma and IgG2a responses in vivo. In addition, IL-1 can promote Th2 development in an IL-4-independent manner in vitro. Thus, the balance between endogenous IL-1 and IL-1Ra during the primary immune response can be an important factor in determining the antigen-specific effector function of T cells.

An activating mutation in the gamma1 subunit of the AMP-activated protein kinase

The AMP-activated protein kinase (AMPK) is a heterotrimeric protein composed of a catalytic alpha subunit and two regulatory subunits, beta and gamma. The gamma subunit is essential for enzyme activity by virtue of its binding to the C-terminus of the alpha subunit and appears to play some role in the determination of AMP sensitivity. We demonstrate that a gamma1R70Q mutation causes a marked increase in AMPK activity and renders it largely AMP-independent. This activation is associated with increased phosphorylation of the alpha subunit activation loop T172. These in vitro characteristics of AMPK are also reflected in increased intracellular phosphorylation of one of its major substrates, acetyl-CoA carboxylase. These data illustrate the importance of the gamma1 subunit in the regulation of AMPK and its modulation by AMP.

Induction of CD8 T cells by vaccination with recombinant adenovirus expressing human papillomavirus type 16 E5 gene reduces tumor growth

The potential of the E5 protein as a tumor vaccine candidate has not been explored yet. In this study, we evaluate the human papillomavirus type 16 (HPV-16) E5 protein delivered by an adenovirus vector as a tumor vaccine for cervical lesions. The results demonstrate that a single intramuscular injection of a recombinant adenovirus carrying the HPV-16 E5 gene into syngeneic animals can reduce the growth of tumors which contain E5 gene expression. Moreover, the E5 vaccine-induced tumor protection occurs through CD8 T cells but not through CD4 T cells in in vitro assays. In addition, our studies using knockout mice with distinct T-cell deficiencies confirm that cytotoxic T-lymphocyte-induced tumor protection is CD8 dependent but CD4 independent. Hence, HPV-16 E5 can be regarded as a tumor rejection antigen.

Potent induction of long-term CD8+ T cell memory by short-term IL-4 exposure during T cell receptor stimulation

An important goal of vaccination is to achieve long-term survival of functional memory T cells. Using a MHC-compatible adoptive transfer system, we show here that a short, 3-day IL-4 but not IL-2 or IL-12 exposure during in vitro T cell receptor stimulation of naive CD8(+) T cells induced long-lasting in vivo memory. Such long-term memory CD8(+) T cells expressed antigen-specific cytotoxicity and the potential for IFN-gamma and IL-4 production. Our results support the concept that functional T cell longevity can be regulated by cytokines during initial antigen encounter and provide a rational foundation for vaccine development. They also may have implications in formulating optimal therapeutic regimens of ex vivo expanded autologous cancer- and HIV-specific CD8(+) T cells. In addition, the availability of large numbers of memory CD8(+) T cells generated through our high-efficiency system should facilitate progress in the molecular dissection of CD8(+) T cell memory development.

Recombinant adeno-associated virus expressing human papillomavirus type 16 E7 peptide DNA fused with heat shock protein DNA as a potential vaccine for cervical cancer

In this study, we explore a potential vaccine for human papillomavirus (HPV)-induced tumors, using heat shock protein as an adjuvant, a peptide vaccine for safety, and adeno-associated virus (AAV) as a gene delivery vector. The tumor vaccine was devised by constructing a chimeric gene which contained HPV type 16 E7 cytotoxic T-lymphocyte (CTL) epitope DNA (M. C. Feltkamp, H. L. Smits, M. P. Vierboom, R. P. Minnaar, B. M. de Jongh, J. W. Drijfhout, J. ter Schegget, C. J. Melief, and W. M. Kast, Eur. J. Immunol. 23:2242-2249, 1993) fused with the heat shock protein gene as a tumor vaccine delivered via AAV. Our results demonstrate that this vaccine can eliminate tumor cells in syngeneic animals and induce CD4- and CD8-dependent CTL activity in vitro. Moreover, studies with knockout mice with distinct T-cell deficiencies confirm that CTL-induced tumor protection is CD4 and CD8 dependent. Taken together, the evidence indicates that this chimeric gene delivered by AAV has potential as a cervical cancer vaccine.

Recent developments in CD8+ T-lymphocyte memory research

Appropriately activated CD8+ T cells differentiate into cytotoxic effectors capable of eliminating cancer cells and virally infected cells. Successful generation and maintenance of effective CD8+ T-cell memory, through either natural infection or through vaccination, establishes long-term protection against various pathogenic agents and, therefore, contributes significantly to our health. This report is a review of recent advances in CD8+ T-cell memory research. The pool of memory CD8+ T cells is maintained through a mechanism of rapid turnover that is antigen-independent, class I major histocompatibility complex (MHC I) antigen-dependent, and, potentially, IL-15-dependent. Memory CD8+ T cells, in marked contrast to naive CD8+ T cells, constitutively express cytotoxic effector function in the absence of antigen stimulation. Furthermore, the vast majority of activated CD8+ T cells in mice infected with lymphocytic choriomeningitis virus are antigen-specific, prompting revision of the commonly held view that many antigen-nonspecific CD8+ T cells are activated in response to viral infection. These newly published results not only provide exciting insights into the inner workings of CD8+ memory maintenance, but they also establish a sound foundation for future investigation. As more detailed molecular and cellular mechanisms of the regulation of memory CD8+ T-cell survival emerge, the most exciting challenge will be to apply this understanding toward the rational design of vaccines and immunotherapies. These potentials are even more relevant in view of the critical nature of CD8+ T cells in combating viral infection and cancer, and the relative paucity of effective drugs against these diseases.

Age-Associated Rapid and Stat6-Independent IL-4 Production by NK1−CD4+8− Thymus T Lymphocytes

The source of IL-4 required for priming naive T cells into IL-4-secreting effectors has not been clearly identified. Here we show that upon TCR stimulation, thymus NK1−CD4+8− T cells produced IL-4, the magnitude of which was inversely correlated with age. This IL-4 production response by Th2-prone BALB/c mice was ∼9-fold that of Th1-prone C57BL/10 mice. More than 90% of activated NK1−CD4+8− thymocytes did not use the invariant Vα14-Jα281 chain characteristic of typical CD1-restricted NK1+CD4+ T cells. Stat6-null NK1−CD4+8− thymocytes produced bioactive IL-4, with induction of IL-4 mRNA expression within 1 h of stimulation. Our results support the possibility that TCR repertoire-diverse conventional NK1−CD4+ T cells are a potential IL-4 source for directing naive T cells toward Th2/type 2 CD8+ T cell (Tc2) effector development.

Age-associated rapid and Stat6-independent IL-4 production by NK1-CD4+8- thymus T lymphocytes

The source of IL-4 required for priming naive T cells into IL-4-secreting effectors has not been clearly identified. Here we show that upon TCR stimulation, thymus NK1-CD4+8- T cells produced IL-4, the magnitude of which was inversely correlated with age. This IL-4 production response by Th2-prone BALB/c mice was approximately 9-fold that of Th1-prone C57BL/10 mice. More than 90% of activated NK1-CD4+8- thymocytes did not use the invariant V alpha 14-J alpha 281 chain characteristic of typical CD1-restricted NK1+CD4+ T cells. Stat6-null NK1-CD4+8- thymocytes produced bioactive IL-4, with induction of IL-4 mRNA expression within 1 h of stimulation. Our results support the possibility that TCR repertoire-diverse conventional NK1-CD4+ T cells are a potential IL-4 source for directing naive T cells toward Th2/type 2 CD8+ T cell (Tc2) effector development.

Lymphokine regulation of activation-induced apoptosis in T cells of IL-2 and IL-2R beta knockout mice

Recent studies using IL-2R alpha knockout mice have generated conflicting results regarding the hypothesis that IL-2/IL-2R interaction is obligatory for the development of AICD, which plays a central and pivotal role in maintaining peripheral tolerance. A relevant consequence of AICD defect is the demonstrated development of autoimmune lymphoproliferative disease in IL-2, IL-2R alpha, and IL-2R beta knockout mice, but not in IL-4, IL-7, or IL-7R knockout mice. Whether IL-4, IL-7, or IL-15 can provide the required signal for AICD development is addressed here using IL-2 and IL-2R beta knockout mice. Lymph node T cells from knockout mice were stimulated with Con A plus rIL-1 for 3 days and then maintained in high concentrations of rIL-4, rIL-7, or rIL-15 for an additional 3 days before they were subjected to AICD analysis. Our study demonstrates that IL-4, IL-7, and IL-15 can transduce signals critical for AICD development in the absence of IL-2-mediated signals. The requirement for relatively high concentrations of these lymphokines suggests their limited role in maintaining peripheral T cell tolerance, thus explaining the differential expression of autoimmune lymphoproliferative disease in the targeted mutant strains described above.

Retinoblastoma gene deficiency has mitogenic but not tumorigenic effects on erythropoiesis

The retinoblastoma protein (Rb), an important ubiquitous cell cycle regulator, was initially identified as the retinoblastoma tumor suppressor. To further address the activities of Rb in proliferation and tumorigenesis in the hematopoietic lineage, we transplanted Rb-/- fetal liver cells into sibling mice and assessed the outcome of Rb-/- hematopoietic cells in both short-term and long-term studies. Rb-/- hematopoietic cells rescued lethally irradiated mice with an efficiency comparable to that of wild-type cells. In spleen colony-forming unit assays, proliferation rates of the Rb-/- cells were greater than those of the wild-type cells. Similarly, in vitro burst-forming unit-erythroid and colony-forming unit-erythroid assays showed increased erythroid colony numbers from Rb-/- embryonic livers. Recipients of Rb-/- cells lived for more than 15-18 months, and most blood cell lineages matured normally with the expected switch from fetal to adult hemoglobin. However, the continued presence of nucleated erythrocytes in the peripheral blood and extensive extramedullary erythropoiesis indicated that the Rb-/- erythrocytes were not completely normal. No erythroleukemia developed during the 15-18 month period following transplantation. These results demonstrate the mitogenic effect but not tumorigenic transformation in erythrocyte lineage in the absence of Rb, which is distinct from the effect of Rb deficiency in neuroectodermal cells. The study supports the prevalent model that loss of the ubiquitously expressed tumor suppressor gene predisposes to only a limited spectrum of tumors.

Deficient CD4+ T cell proliferation in the class 1 MHC-restricted 2C TCR-transgenic mouse

A comparative study of immune function and marker expression of CD4+ T cells from MHC class 1-restricted 2C TCR-transgenic (2C+) and control transgene-negative littermate (2C-) mice was performed. While 2C+CD4+ T cells resembled memory T cells on the basis of CD44highCD45RBlow expression, the majority of 2C-CD4+ T cells were of the CD44lowCD45RBhigh naive phenotype. Slightly lower levels of TCR-beta and CD3 were found on 2C+CD4+ T cell than 2C-CD4+ T cells. Vigorous proliferation by 2C-CD4+ T cells was observed upon stimulation with 1) anti-CD3 mAb presented through the FcR of macrophages; 2) immobilized (plate-bound) anti-CD3 + anti-CD28 mAbs; and 3) PMA + ionomycin. In marked contrast, all three mitogenic stimuli stimulated highly deficient proliferative responses by 2C+CD4+ T cells. However, significant IL-2 production was detected both in anti-CD3 and in PMA + ionomycin-stimulated cultures of 2C+CD4+ T cells. While intracellular calcium in 2C-CD4+ T cells rapidly increased following anti-CD3 addition, no such increase was observed for similarly stimulated 2C+CD4+ T cells. Anti-CD28, PMA, and coculture with 2C-CD4+ T cells each failed to significantly correct the deficient 2C+CD4+ T cells proliferation as induced by anti-CD3. In addition, IL-2, IL-4, and IL-7 supplements also failed to reverse the deficient proliferation of 2C+CD4+ T cells despite expression of IL-2R component alpha-, beta-chains and the gamma-chain common also to IL-4R and IL-7R. Thymus CD4+8- T cells from the 2C-transgenic mouse were similarly deficient in proliferation as spleen CD4+ T cells. A small subpopulation of CD4+ T cell from the 2C-transgenic mouse expressed the transgenic TCR alpha:beta heterodimer as detected by the 1B2 anti-2C clonotypic mAb; both 1B2+ and 1B2- subpopulations proliferated poorly in response to anti-CD3 and to PMA + ionomycin. These results raise the possibility that TCR engagement with MHC class 1 molecules during early intrathymic development can result in the emergence of CD4+ T cells characterized by unusual marker expression and function.

Deficient CD4+ T cell proliferation in the class 1 MHC-restricted 2C TCR-transgenic mouse

A comparative study of immune function and marker expression of CD4+ T cells from MHC class 1-restricted 2C TCR-transgenic (2C+) and control transgene-negative littermate (2C-) mice was performed. While 2C+CD4+ T cells resembled memory T cells on the basis of CD44highCD45RBlow expression, the majority of 2C-CD4+ T cells were of the CD44lowCD45RBhigh naive phenotype. Slightly lower levels of TCR-beta and CD3 were found on 2C+CD4+ T cell than 2C-CD4+ T cells. Vigorous proliferation by 2C-CD4+ T cells was observed upon stimulation with 1) anti-CD3 mAb presented through the FcR of macrophages; 2) immobilized (plate-bound) anti-CD3 + anti-CD28 mAbs; and 3) PMA + ionomycin. In marked contrast, all three mitogenic stimuli stimulated highly deficient proliferative responses by 2C+CD4+ T cells. However, significant IL-2 production was detected both in anti-CD3 and in PMA + ionomycin-stimulated cultures of 2C+CD4+ T cells. While intracellular calcium in 2C-CD4+ T cells rapidly increased following anti-CD3 addition, no such increase was observed for similarly stimulated 2C+CD4+ T cells. Anti-CD28, PMA, and coculture with 2C-CD4+ T cells each failed to significantly correct the deficient 2C+CD4+ T cells proliferation as induced by anti-CD3. In addition, IL-2, IL-4, and IL-7 supplements also failed to reverse the deficient proliferation of 2C+CD4+ T cells despite expression of IL-2R component alpha-, beta-chains and the gamma-chain common also to IL-4R and IL-7R. Thymus CD4+8- T cells from the 2C-transgenic mouse were similarly deficient in proliferation as spleen CD4+ T cells. A small subpopulation of CD4+ T cell from the 2C-transgenic mouse expressed the transgenic TCR alpha:beta heterodimer as detected by the 1B2 anti-2C clonotypic mAb; both 1B2+ and 1B2- subpopulations proliferated poorly in response to anti-CD3 and to PMA + ionomycin. These results raise the possibility that TCR engagement with MHC class 1 molecules during early intrathymic development can result in the emergence of CD4+ T cells characterized by unusual marker expression and function.

Host responses in patients with generalized refractory periodontitis

Although patients with refractory periodontitis have been widely reported, no clear biologic profile of these patients has been noted. The purpose of the present study was to evaluate host responsiveness of a well-defined group of refractory periodontitis patients by determining the effect of a lipopolysaccharide (LPS) challenge on monocyte surface receptor density and on the release of inflammatory mediators. Venous blood was obtained from 7 refractory periodontitis, 8 stable periodontal maintenance, and 8 gingivitis patients with no evidence of periodontitis. Mononuclear cells were cultured in either control media or media treated with Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), or Salmonella typhimurium (S. typh) LPS. At 0 and 24 hours supernatants were assayed for prostaglandin-E2 (PGE2) and interleukin-1 beta (Il-1 beta) release by ELISA. Using flow cytometry the density of specific monocyte surface receptors were assayed with Mo3e and LeuM3 monoclonal antibodies (mAb); T-cell CD4/CD8 ratios were assayed with OKT-3, OKT-4, and OKT-8 mAb. After 24 hours incubation with Pg or S. typh LPS, the upregulation of the Mo3e receptor was significantly decreased for refractory periodontitis patients (P < 0.05) when compared to gingivitis and to stable maintenance patients. In refractory periodontitis patients the T-cell CD4/CD8 ratio was decreased. Upon stimulation with Pg or S. typh LPS, monocytes from stable maintenance and refractory periodontitis patients released more Il-1 beta (P < 0.05) and PGE2 (P = 0.13 and 0.15) than monocytes from gingivitis subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Mitogen-induced IL-2 production and proliferation at defined stages of T helper cell development

Th cell development inside the thymus can be defined on the basis of qualitative and quantitative CD4 and CD8 marker expression and follows the pathway of CD4-8- cells----CD4+8+ cells----CD4+8low cells----CD4+8- cells, which presumably emigrate to seed the periphery and serve as functionally mature Th cells. The various cell subpopulations at defined developmental stages were isolated by electronic cell sorting and examined for mitogen induced IL-2 production and cell proliferation responses. For TCR-alpha beta-bearing CD4+8+ and CD4+8low thymocytes that are actively engaged in positive and negative selection processes, negligible to low levels of IL-2 production and cell proliferation were observed in response to TCR:CD3 triggering or to the combined activation of protein kinase C and calcium mobilization mediated by PMA and ionomycin, respectively. For CD4-8- TCR-alpha beta early thymocytes that have not yet entered the selection process, PMA + ionomycin induced significant cell proliferation but little IL-2 production, in the absence of added IL-1. However, addition of IL-1 caused a powerful induction of IL-2 production that was accompanied by increased cell proliferation. Triggering of the TCR:CD3 complex had no effect on CD4-8-TCR(-)-alpha beta thymocytes as they do not express detectable levels of TCR-alpha beta. For thymus CD4+8- Th cells, the first cells that have completed TCR repertoire selection, vigorous proliferation was observed in response to TCR:CD3 triggering in the presence of added IL-2. However, the development of IL-2 responsiveness was not accompanied by high level IL-2 inducibility as TCR:CD3 triggering caused only marginal IL-2 production. In contrast, spleen CD4+8- T cells, the most "mature" representatives of Th cells, expressed high levels of IL-2 production as well as IL-2 responsiveness in response to TCR:CD3-mediated stimulation. The lack of anti-TCR-induced IL-2 production by thymus CD4+8- T cells was not due to an intrinsic defect as high levels of IL-2 production was induced by PMA + ionomycin. Possible reasons for the temporal acquisition and differential control of IL-2 inducibility and IL-2 responsiveness are discussed in the context of established Th cell development pathway.

Induction of high level IL-2 production in CD4+8- T helper lymphocytes requires post-thymic development

Triggering of the CD3:TCR complex by optimal concentrations of anti-CD3, anti-TCR beta-chain, and allogeneic stimulator cells induced dramatically higher levels (fivefold for anti-CD3, greater than 10-fold for anti-TCR beta-chain, 84-fold for alloantigen) of IL-2 production in spleen CD4+8- T cells than their thymic counterparts, despite comparable levels of CD3 and TCR beta-chain expression. The nature of the reduced IL-2 production was examined by analysis of anti-CD3-induced IL-2 production at the single cell level. The frequency of IL-2-producing cells in spleen CD4+8- T cells (40.0%) was approximately threefold that of thymus CD4+8- T cells (14.5%). Furthermore, the average IL-2 levels among positive IL-2 producers was also approximately threefold higher in spleen CD4+8- T cells than their thymic counterparts. Adoptive transfer of purified Thy-1.2+ CD4+8- T cells into Thy-1.1-congenic hosts provided a physiologic and histocompatible system that enabled identification of transferred donor (Thy-1.2+) among a sea of host (Thy-1.2-) CD4+ T cells, whose immune function with respect to IL-2 inducibility was examined after isolation by electronic cell sorting. Donor CD4+ T cells thus isolated from host spleen shortly (1 day) after i.v. transfer of thymus CD4+8- T cells were similar to freshly isolated thymus CD4+8- T cells in that they both produced little IL-2 in response to anti-CD3. However, by day 3 post-transfer, IL-2 production by donor CD4+8- T cells had more than doubled and by day 8, they produced IL-2 levels comparable to those of host spleen CD4+8- T cells. A similar acquisition of high level IL-2 inducibility in thymus CD4+8- T cells upon i.v. transfer into Thy-1.1-congenic hosts was also observed using allogeneic cells as the stimulus of IL-2 production. When thymus CD4+8- T cells were intra-thymically transferred into Thy-1.1-congenic hosts, those donor cells that emigrated to the periphery became high IL-2 producers in a time-dependent manner, whereas those that remained inside the thymus showed no signs of up-regulation in IL-2 inducibility. Intrathymic transfer of CD4-8- thymocytes revealed that the most recent thymic emigrant CD4+8- T cells contained few IL-2-producing cells and were not functionally mature with respect to high level IL-2 inducibility.

Mitogen-induced IL-2 production and proliferation at defined stages of T helper cell development

Th cell development inside the thymus can be defined on the basis of qualitative and quantitative CD4 and CD8 marker expression and follows the pathway of CD4-8- cells----CD4+8+ cells----CD4+8low cells----CD4+8- cells, which presumably emigrate to seed the periphery and serve as functionally mature Th cells. The various cell subpopulations at defined developmental stages were isolated by electronic cell sorting and examined for mitogen induced IL-2 production and cell proliferation responses. For TCR-alpha beta-bearing CD4+8+ and CD4+8low thymocytes that are actively engaged in positive and negative selection processes, negligible to low levels of IL-2 production and cell proliferation were observed in response to TCR:CD3 triggering or to the combined activation of protein kinase C and calcium mobilization mediated by PMA and ionomycin, respectively. For CD4-8- TCR-alpha beta early thymocytes that have not yet entered the selection process, PMA + ionomycin induced significant cell proliferation but little IL-2 production, in the absence of added IL-1. However, addition of IL-1 caused a powerful induction of IL-2 production that was accompanied by increased cell proliferation. Triggering of the TCR:CD3 complex had no effect on CD4-8-TCR(-)-alpha beta thymocytes as they do not express detectable levels of TCR-alpha beta. For thymus CD4+8- Th cells, the first cells that have completed TCR repertoire selection, vigorous proliferation was observed in response to TCR:CD3 triggering in the presence of added IL-2. However, the development of IL-2 responsiveness was not accompanied by high level IL-2 inducibility as TCR:CD3 triggering caused only marginal IL-2 production. In contrast, spleen CD4+8- T cells, the most "mature" representatives of Th cells, expressed high levels of IL-2 production as well as IL-2 responsiveness in response to TCR:CD3-mediated stimulation. The lack of anti-TCR-induced IL-2 production by thymus CD4+8- T cells was not due to an intrinsic defect as high levels of IL-2 production was induced by PMA + ionomycin. Possible reasons for the temporal acquisition and differential control of IL-2 inducibility and IL-2 responsiveness are discussed in the context of established Th cell development pathway.

Induction of high level IL-2 production in CD4+8- T helper lymphocytes requires post-thymic development

Triggering of the CD3:TCR complex by optimal concentrations of anti-CD3, anti-TCR beta-chain, and allogeneic stimulator cells induced dramatically higher levels (fivefold for anti-CD3, greater than 10-fold for anti-TCR beta-chain, 84-fold for alloantigen) of IL-2 production in spleen CD4+8- T cells than their thymic counterparts, despite comparable levels of CD3 and TCR beta-chain expression. The nature of the reduced IL-2 production was examined by analysis of anti-CD3-induced IL-2 production at the single cell level. The frequency of IL-2-producing cells in spleen CD4+8- T cells (40.0%) was approximately threefold that of thymus CD4+8- T cells (14.5%). Furthermore, the average IL-2 levels among positive IL-2 producers was also approximately threefold higher in spleen CD4+8- T cells than their thymic counterparts. Adoptive transfer of purified Thy-1.2+ CD4+8- T cells into Thy-1.1-congenic hosts provided a physiologic and histocompatible system that enabled identification of transferred donor (Thy-1.2+) among a sea of host (Thy-1.2-) CD4+ T cells, whose immune function with respect to IL-2 inducibility was examined after isolation by electronic cell sorting. Donor CD4+ T cells thus isolated from host spleen shortly (1 day) after i.v. transfer of thymus CD4+8- T cells were similar to freshly isolated thymus CD4+8- T cells in that they both produced little IL-2 in response to anti-CD3. However, by day 3 post-transfer, IL-2 production by donor CD4+8- T cells had more than doubled and by day 8, they produced IL-2 levels comparable to those of host spleen CD4+8- T cells. A similar acquisition of high level IL-2 inducibility in thymus CD4+8- T cells upon i.v. transfer into Thy-1.1-congenic hosts was also observed using allogeneic cells as the stimulus of IL-2 production. When thymus CD4+8- T cells were intra-thymically transferred into Thy-1.1-congenic hosts, those donor cells that emigrated to the periphery became high IL-2 producers in a time-dependent manner, whereas those that remained inside the thymus showed no signs of up-regulation in IL-2 inducibility. Intrathymic transfer of CD4-8- thymocytes revealed that the most recent thymic emigrant CD4+8- T cells contained few IL-2-producing cells and were not functionally mature with respect to high level IL-2 inducibility.

Subpopulations of CD8+ cytotoxic T cell precursors collaborate in the absence of conventional CD4+ helper T cells

Four different subpopulations (Ly6Cneg, Ly6Clow, Ly6Cint, and Ly6Chi) of CD8+ T cells were arbitrarily defined on the basis of differential expression of Ly6C Ag. By combining the processes of electronic cell sorting and automated cell deposition, small numbers of respective CD8+ T cell subpopulations were directly deposited into tissue culture wells in which mitogen-stimulated responses were studied. Anti-CD3-stimulated proliferation and IL-2 production were the strongest by Ly6Cneg/Ly6Clow T cells, moderate for Ly6Cint T cells, and highly deficient for Ly6Chi T cells. The level of IL-2 production for Ly6Cneg CD8+ T cells was comparable to that of conventional CD4+ Th cells. Allogeneic stimulator cells elicited a strong cytotoxic response by Ly6Cneg + low but not Ly6Chi CD8+ T cells in the absence of added lymphokines. When IL-2 was supplied in excess, anti-CD3 induced comparable levels of cell proliferation and cytotoxic activity in Ly6Cneg, Ly6Clow, Ly6Cint, and Ly6Chi CD8+ T cells whereas alloantigen stimulated an approximate fivefold higher cytotoxic response by Ly6Chi than Ly6Cneg + low CD8+ T cells. Stimulation of co-cultures of B10 (CD8b) Ly6Cneg + low and congenic B10.CD8a Ly6Chi CD8+ T cells in the absence of added lymphokines, followed by selective elimination of activated CD8.1+ (CD8.2+) T cells by anti-CD8.1 (anti-CD8.2) + C treatment, allowed the demonstration that help provided by Ly6Cneg + low T cells can be effectively used by both Ly6Cneg + low and Ly6Chi T cells in anti-CD3 and alloantigen induced proliferative and cytotoxic responses, respectively.

Subpopulations of CD8+ cytotoxic T cell precursors collaborate in the absence of conventional CD4+ helper T cells

Four different subpopulations (Ly6Cneg, Ly6Clow, Ly6Cint, and Ly6Chi) of CD8+ T cells were arbitrarily defined on the basis of differential expression of Ly6C Ag. By combining the processes of electronic cell sorting and automated cell deposition, small numbers of respective CD8+ T cell subpopulations were directly deposited into tissue culture wells in which mitogen-stimulated responses were studied. Anti-CD3-stimulated proliferation and IL-2 production were the strongest by Ly6Cneg/Ly6Clow T cells, moderate for Ly6Cint T cells, and highly deficient for Ly6Chi T cells. The level of IL-2 production for Ly6Cneg CD8+ T cells was comparable to that of conventional CD4+ Th cells. Allogeneic stimulator cells elicited a strong cytotoxic response by Ly6Cneg + low but not Ly6Chi CD8+ T cells in the absence of added lymphokines. When IL-2 was supplied in excess, anti-CD3 induced comparable levels of cell proliferation and cytotoxic activity in Ly6Cneg, Ly6Clow, Ly6Cint, and Ly6Chi CD8+ T cells whereas alloantigen stimulated an approximate fivefold higher cytotoxic response by Ly6Chi than Ly6Cneg + low CD8+ T cells. Stimulation of co-cultures of B10 (CD8b) Ly6Cneg + low and congenic B10.CD8a Ly6Chi CD8+ T cells in the absence of added lymphokines, followed by selective elimination of activated CD8.1+ (CD8.2+) T cells by anti-CD8.1 (anti-CD8.2) + C treatment, allowed the demonstration that help provided by Ly6Cneg + low T cells can be effectively used by both Ly6Cneg + low and Ly6Chi T cells in anti-CD3 and alloantigen induced proliferative and cytotoxic responses, respectively.

Private hospitals in public health systems

Heterogeneity of cancer stem/progenitor cells that give rise to different forms of cancer has been well demonstrated for leukemia. However, this fundamental concept has yet to be established for solid tumors including breast cancer. In this communication, we analyzed solid tumor cancer stem cell markers in human breast cancer cell lines and primary specimens using flow cytometry. The stem/progenitor cell properties of different marker expressing-cell populations were further assessed by in vitro soft agar colony formation assay and the ability to form tumors in NOD/SCID mice. We found that the expression of stem cell markers varied greatly among breast cancer cell lines. In MDA-MB-231 cells, PROCR and ESA, instead of the widely used breast cancer stem cell markers CD44⁺/CD24^-/low and ALDH, could be used to highly enrich cancer stem/progenitor cell populations which exhibited the ability to self renew and divide asymmetrically. Furthermore, the PROCR⁺/ESA⁺ cells expressed epithelial-mesenchymal transition markers. PROCR could also be used to enrich cells with colony forming ability from MB-361 cells. Moreover, consistent with the marker profiling using cell lines, the expression of stem cell markers differed greatly among primary tumors. There was an association between metastasis status and a high prevalence of certain markers including CD44⁺/CD24^−/low, ESA⁺, CD133⁺, CXCR4⁺ and PROCR⁺ in primary tumor cells. Taken together, these results suggest that similar to leukemia, several stem/progenitor cell-like subpopulations can exist in breast cancer.