CD28 days later: Resurrecting costimulation for CD8+ memory T cells

Rapid activation and proliferative expansion of specific CD8⁺ memory T (CD8⁺T_M) cells upon antigen re‐encounter is a critical component of the adaptive immune response that confers enhanced immune protection. In this context, however, the requirements for costimulation in general, and CD28 signaling in particular, remain incompletely defined. In the current issue of the European Journal of Immunology, Fröhlich et al. [Eur. J. Immunol. 2016. 46: 1644‐1655] provide definitive evidence that optimal elaboration of CD8⁺T_M‐cell recall responses is indeed contingent on CD28 expressed by these cells. Here, we discuss the “CD28 costimulation paradigm” in its historical context and highlight some of the unresolved complexities pertaining to CD28‐dependent interactions that shape CD8⁺ T‐cell phenotypes, functionalities, and recall reactivity.     

Impaired expression of CD28 on T cells in hairy cell leukemia

T cells from patients with active hairy cell leukemia (HCL), a chronic B cell malignancy, show poor proliferation in response to allogeneic peripheral blood mononuclear cells (PBMC). In order to study the T cell dysfunction, the expression of several adhesion and costimulatory molecules was analyzed by flow cytometry. Circulating T cells from HCL patients showed increased percentages of CD28(-) in all T cell subsets. In some patients the percentage of CD28(-) T cells within the CD4(+) subset was increased up to 80%. These CD4(+)CD28(-) T cells did not proliferate in a mixed lymphocyte culture (MLC) against allogeneic PBMC. After enrichment for CD4(+)CD28(+) T cells, the proliferative response in the MLC was recovered, but this response was still lower than the proliferative response from control T cells. In conclusion, lack of CD28 on T cells and a restricted T cell repertoire may contribute to immune deficiency in patients with HCL.     

Peripheral human CD8(+)CD28(+)T lymphocytes give rise to CD28(-)progeny, but IL-4 prevents loss of CD28 expression.

At birth, virtually all peripheral CD8(+) T cells express the CD28 co-stimulatory molecule, but healthy human adults accumulate CD28(-)CD8(+) T cells that often express the CD57 marker. While these CD28(-) subpopulations are known to exert effector-type functions, the generation, maintenance and regulation of CD28(-) (CD57(+) or CD57(-)) subpopulations remain unresolved. Here, we compared the differentiation of CD8(+)CD28(bright)CD57(-) T cells purified from healthy adults or neonates and propagated in IL-2, alone or with IL-4. With IL-2 alone, CD8(+)CD28(bright)CD57(-) T cell cultures yielded a prevailing CD28(-) subpopulation. The few persisting CD28(dim) and the major CD28(-) cells were characterized by similar telomere shortening at the plateau phase of cell growth. Cultures from adults donors generated four final CD8(+) phenotypes: a major CD28(-)CD57(+), and three minor CD28(-)CD57(-), CD28(dim)CD57(-) and CD28(dim)CD57(dim). These four end-stage CD8(+) subpopulations displayed a fairly similar representation of TCR V(beta) genes. In cultures initiated with umbilical cord blood, virtually all the original CD8(+)CD28(bright) T cells lost expression of CD28, but none acquired CD57 with IL-2 alone. IL-4 impacted on the differentiation pathways of the CD8(+)CD28(bright)CD57(-) T cells: the addition of IL-4 led both the neonatal and the adult lymphocytes to keep their expression of CD28. Thus, CD8(+)CD28(bright)CD57(-) T cells can give rise to four end-stage subpopulations, the balance of which is controlled by both the cytokine environment, IL-4 in particular, and the proportions of naive and memory CD8(+)CD28(+) T cells.     

CD4+CD45RA+T cells from adults respond to recall antigens after CD28 ligation

The leukocyte common antigen isoforms CD45RA and CD45RO havelong been used to discriminate human naive and memory T cellsrespectively. This model was largely based on the observationthat CD45RO⁺ T cells respond preferentially to and show a higherfrequency of precursors specific for recall antigens. However,CD45RA⁺ T cells have more stringent requirements for stimulationand standard in vitro assays may favour CD45RO⁺ cells in thisrespect. We tested the hypothesis that CD45RAf T cells respondpoorly to in vitro stimulation with recall antigens becauseof inadequate stimulation rather than a lack of precursors.Limiting dilution analyses (LDA) for tetanus toxoid (lT)-specificT cells were performed in the presence or absence of exogenousantLCD28 antibody. Addition of antLCD28 yielded no proliferationin the absence of specific antigen. The precursor frequencyfor lT in the CD4⁺ CD45RO⁺ population was –1:4000, whilethe frequency of CD4⁺ CD45RA⁺ T cells specific for lT was 4-to >>20-fold lower. Addition of anti-CD28 antibody didnot significantly alter the apparent precursor frequency forCD45RA⁺ cells but yielded an enhancement of the value for CD45RA⁺cells by 3- to >>5-fold. No enhancement of antigen-specificproliferation by antLCD28 was observed with CD45RA⁺ T cellsderived from cord blood, although phytohemagglutinin responsesof these cells were amplified by CD28 antibody. These resultsindicate that conventional LDA underestimate the true precursorfrequency of antigen-specific cells within the adult CD45RA⁺population and support the possibility that a small number ofcells revert from a primed (CD45RO⁺) to an unprimed (CD45RA⁺)state. The majority of memory T cells, however, appear to residein the CD45RO⁺ population     

CD8+ T cells and not CD4+ T cells are hyporesponsive to CD28- and CD40L-mediated activation in HIV-infected subjects

T cell dysfunction in HIV-infected subjects could be the consequence of altered sensitivity of CD4⁺ or CD8⁺ T cells to various costimulatory signals. Therefore, we studied proliferation and cytokine production in highly purified CD8⁺ and CD4⁺ T cells from HIV-infected and HIV⁻ subjects, induced by co-activation via cell-bound CD80, CD86 and CD40 or by allo-activation. Regardless of the nature of the first and the costimulatory signal, CD8⁺ T cells from patients proliferated consistently less than controls, while responses from CD4⁺ T cells were similar in patients and controls. This phenomenon was observed after ligation of CD28 combined with anti-CD3 or phorbol myristate acetate (PMA), but also after allogeneic stimulation and after activation by CD40 and anti-CD3. Anti-CD3 combined with CD80 or CD86 induced a mixed Th1/Th2-type cytokine profile in both CD4⁺ and CD8⁺ T cells from controls, whereas anti-CD3 plus CD40 induced only low levels of Th2-type cytokines and no interferon-gamma (IFN-γ) in CD4⁺ T cells. Compared with controls, CD4⁺ T cells from patients produced slightly lower levels of IL-10 but equal amounts of IFN-γ, IL-4 and IL-5, while CD8⁺ T cells from patients produced less of all cytokines tested. In conclusion, responses of purified CD4⁺ T cells from HIV⁺ subjects to various costimulatory pathways are relatively intact, whereas CD8⁺ T cells are hyporesponsive at the level of proliferation and cytokine production. A generalized intrinsic CD8⁺ T cell failure might contribute to viral and neoplastic complications of HIV infection.     

Human mucosal CD4+ T cells but not blood CD4+ T cells respond vigorously towards CD28 engagement

Human lamina propria T lymphocytes (LPT) possess functional properties profoundly different from those of peripheral blood T lymphocytes (PBT). While they are characterized by a low proliferative response to T cell receptor (TCR)/CD3 stimulation in vitro their responsiveness to activation through the 'co-stimulatory' CD2-receptor is enhanced when compared to PBT. In this study, we demonstrate that engagement of another co-stimulatory receptor on both LPT and PBT, namely CD28, by a single monoclonal antibody (mAb), respectively, strongly activates the former but not the latter through a PI3-kinase dependent signalling pathway leading to the production of inflammatory cytokines such as interleukin (IL)-2, tumour necrosis factor (TNF)-α, interferon (IFN)-γ and granulocyte-macrophage colony-stimulating factor (GM-CSF). In addition to the high sensitivity of LPT to CD2 stimulation, this finding supports the notion that 'non-specific/innate' mechanisms to activate T lymphocytes play a predominant role vis-à-vis'TCR driven/adaptive' responses in the intestinal mucosa. Furthermore, it suggests that results from preclinical tests for therapeutic antibodies performed with human blood derived T cells are probably insufficient to predict reactivities of tissue-resident immune cells, which--given their quantitative predominance--may critically determine the in-vivo response to such compounds.     

CD4+ T cell help improves CD8+ T cell memory by retained CD27 expression

CD4+ T cell help during the priming of CD8+ T lymphocytes imprints the capacity for optimal secondary expansion upon re-encounter with antigen. Helped memory CD8+ T cells rapidly expand in response to a secondary antigen exposure, even in the absence of T cell help and, are most efficient in protection against a re-infection. In contrast, helpless memory CTL can mediate effector function, but secondary expansion is reduced. How CD4+ T cells instruct CD8+ memory T cells during priming to undergo efficient secondary expansion has not been resolved in detail. Here, we show that memory CTL after infection with lymphocytic choriomeningitis virus are CD27(high) whereas memory CTL primed in the absence of CD4+ T cell have a reduced expression of CD27. Helpless memory CTL produced low amounts of IL-2 and did not efficiently expand after restimulation with peptide in vitro. Blocking experiments with monoclonal antibodies and the use of CD27(-/-) memory CTL revealed that CD27 ligation during restimulation increased autocrine IL-2 production and secondary expansion. Therefore, regulating CD27 expression on memory CTL is a novel mechanism how CD4+ T cells control CTL memory.     

Accumulation of memory T cells from childhood to old age: central and effector memory cells in CD4(+) versus effector memory and terminally differentiated memory cells in CD8(+) compartment

Memory T cells can be classified as central memory (T(CM), CD45RA(neg)CCR7(+)), effector memory (T(EM), CD45RA(neg)CCR7(neg)), and terminally differentiated cells (T(TD), CD45RA(+)CCR7(neg)) with different homing and effector capacities. In 101 healthy subjects aged from 5 to 96 years, distinct dynamics were evidenced between circulating CD4(+) and CD8(+) T cell populations. Naive CD4(+) and CD8(+) T cells decreased linearly with age, CD8(+) twice more rapidly. Memory cells outnumbered naive cells on average at 37.4 in the CD4(+) and 29.5 years of age in the CD8(+) pool. CD4(+) T(CM) and T(EM) cells were positively correlated and increased linearly at a similar rate with age, while CD4(+) T(TD) remained rare. CD8(+) T(EM) and T(TD) accumulated linearly with age, while T(CM) increased only slightly, and each memory subset was negatively correlated to the two others. Almost all CD8(+) T(TD) and some CD8(+) T(EM) had lost CD28 expression. Despite different dynamics, each individual CD4(+) naive and memory subset was correlated to the synonymous CD8(+) subset. Half of the subjects aged 65 years or older were characterized by extremely reduced CD8(+) naive and increased CD8(+) T(TD) cell counts, which could indicate an acceleration of the decay of the immune system from this age onward.     

Differential proliferative responses in subsets of human CD28+cells delineated by BB27 mAb

We report the Identification of a novel 140 kDa disulflde-llnkeddimer expressed by a subset of peripheral blood T lymphocytes.This molecule, which Is recognized by mAb BB27, is also detectedon cells of the myelomonocytlc lineage. In the T cell lineage,Its expression Is positively modulated after lymphocyte activation.A series of double-labeling experiments revealed that BB27 mAbIdentifies new CD4 and CDS cell subsets different from thosedefined by CD45RA, CD45RO, CD26, CD29, CD31, and CD38. Finally,BB27 mAb also subdivides the CD28 subset. Of the utmost interestIs the finding that a proliferative response to CD28 mAb andphorbol myrlstate acetate stimulation is exclusively obtainedin the CD28⁺BB27⁺ cell subset, whereas the CD28⁺BB27^–subset falls to proliferate.     

伴颈动脉粥样硬化脑梗患者CD4+CD28null T细胞CD158j表达和ERK磷酸化水平的关系

Objective To investigate the relationship between CD158j expression and phosphorylated ERK (p-ERK) in CD4+ CD28null T cells in cerebral infarction (CI) patients- with carotid atherosclerosis and its effects on carotid atherosclerotic plaque stability. Methods Percentage of peripheral CD4+ CD28null and the expression of CD158j and perform on CD4+ CD28null cells was analyzed with flow cytometry in 106 CI patients with carotid atherosclerosis, 33 CI patients with normal carotid arteries and in 50 normal controls, respectively; p-ERK expression was assayed with flow cytometry in 36 CI patients with unstable plaque, and serum IFN-γ was detected with ELISA. The intima-media thickness (IMT) of bilateral carotid arteries in all subjects was confirmed by the colour Doppler ultrasonograph imagingResults Percentage of the CD4+ CD28null T cells, expression of CD158j and perform on CD4+ CD28null T cells and the serum IFN-γ levels was dramatically higher in CI patients than that in normal controls, respectively (all P <0.01), which was decreased in an order of CI patients with patients with unstable plaque, stable plaque, carotid artery IMT and with normal carotid artery. A strong positive correlation was observed between the CD158j expression and degree of p-ERK in CI patients with unstable plaque (P < 0. 01). Conclusion CD4+ CD28null T cells were significantly increased in CI patients with carotid atherosclerosis. CD158j might up-regulate p-ERK expression and induce the proliferation of the CD4+ CD28nullT cells; consequently, higher cytokine production such as IFN-γ produced by CD4+ CD28null T cells may cause the formation of unstable plaque.     

伴颈动脉粥样硬化脑梗患者CD4+CD28null T细胞CD158j表达和ERK磷酸化水平的关系

Objective To investigate the relationship between CD158j expression and phosphorylated ERK (p-ERK) in CD4+ CD28null T cells in cerebral infarction (CI) patients- with carotid atherosclerosis and its effects on carotid atherosclerotic plaque stability. Methods Percentage of peripheral CD4+ CD28null and the expression of CD158j and perform on CD4+ CD28null cells was analyzed with flow cytometry in 106 CI patients with carotid atherosclerosis, 33 CI patients with normal carotid arteries and in 50 normal controls, respectively; p-ERK expression was assayed with flow cytometry in 36 CI patients with unstable plaque, and serum IFN-γ was detected with ELISA. The intima-media thickness (IMT) of bilateral carotid arteries in all subjects was confirmed by the colour Doppler ultrasonograph imagingResults Percentage of the CD4+ CD28null T cells, expression of CD158j and perform on CD4+ CD28null T cells and the serum IFN-γ levels was dramatically higher in CI patients than that in normal controls, respectively (all P <0.01), which was decreased in an order of CI patients with patients with unstable plaque, stable plaque, carotid artery IMT and with normal carotid artery. A strong positive correlation was observed between the CD158j expression and degree of p-ERK in CI patients with unstable plaque (P < 0. 01). Conclusion CD4+ CD28null T cells were significantly increased in CI patients with carotid atherosclerosis. CD158j might up-regulate p-ERK expression and induce the proliferation of the CD4+ CD28nullT cells; consequently, higher cytokine production such as IFN-γ produced by CD4+ CD28null T cells may cause the formation of unstable plaque.     

DNA甲基化在急性冠脉综合征患者CD4+CD28-T细胞CD28表达缺失中的作用

目的 通过研究急性冠脉综合征(acute coronary syndrome,ACS)患者外周血CD4+T细胞CD28 mRNA水平和CD28基因启动子调节序列的甲基化状态,旨在探讨DNA甲基化在ACS患者CD4+CD28-T细胞CD28表达缺失中的作用.方法 免疫磁珠分离CD4+T细胞经逆转录后,实时定量PCR(real time-PCR)技术检测CD4+T细胞CD28mRNA的表达水平,亚硫酸氢钠测序检测CD28基因启动子调节序列的甲基化状态.结果 与正常对照组相比,ACS患者CD4+T细胞CD28mRNA表达水平显著减低,差异具有统计学意义[正常对照组比ACS组:(1.066±0.162)比(0.401±0.069),P<0.05].CD28基因启动子区域的甲基化水平显著增高,差异有统计学意义[正常对照组比ACS组:(24.47±3.17)%比(43.33±1.52)%,P<0.05].CD28基因启动子区域DNA甲基化水平与CD28mRNA表达水平呈显著负相关(P=0.01,r=-0.579).结论 ACS患者CD4+T细胞CD28基因启动子区域高甲基化调控了CD28基因转录抑制.DNA甲基化参与了CD4+CD28-T细胞的形成.     

Differentiation of human CD8 T cells: implications for in vivo persistence of CD8+ CD28- cytotoxic effector clones

CD8 T cells contain a distinct subset of CD8+ CD28- cells. These cells are not present at birth and their frequency increases with age. They frequently contain expanded clones using various TCRalphabeta receptors and these clones can represent >50% of all CD8 cells, specially in old subjects or patients with chronic viral infections such as HIV-1. Herein, it is shown that a large fraction of CD8+ CD28- cells expresses intracellular perforin by three-color flow cytometry, in particular when this subset is expanded. Together with their known ability to exert potent re-directed cytotoxicity, this indicates that CD8+ CD28- T cells comprise cytotoxic effector cells. With BrdU labeling, we show that CD8+ CD28- cells derive from CD8+ CD28+ precursors in vitro. In addition, sorted CD8+ CD28+ cells gave rise to a population of CD8+ CD28- cells after allo-stimulation. Moreover, ex vivo CD8+ CD28+ cells contain the majority of CD8 blasts, supporting the notion that they contain the proliferative precursors of CD8+ CD28- cells. CD95 (Fas) expression was lower in CD8+ CD28- cells, and this subset was less prone to spontaneous apoptosis in ex vivo samples and more resistant to activation-induced cell death induced by a superantigen in vitro. Thus, the persistence of expanded clones in vivo in the CD8+ CD28- subset may be explained by antigen-driven differentiation from CD8+ CD28+ memory precursors, with relative resistance to apoptosis as the clones become perforin(+) effector cells.     

CD4 and CD45 regulate qualitatively distinct patterns of calcium mobilization in individual CD4+ T cells

An early consequence of T cell activation is an increase in intracellular calcium concentration. Recent advances in video laser microscopic techniques enable the examination of individual cells over time following stimulation. Such studies have revealed that cells can undergo qualitatively distinct patterns of calcium mobilization, suggesting that different patterns of calcium flux may be associated with different signaling pathways and may differentially affect late events in cell activation. In this report, we identify distinct patterns of calcium mobilization in CD4⁺ T cells following the antibody-mediated cross-linking of either CD3 or CD4, or following the cross-linking of both CD3 and CD4 simultaneously. These effects can be further modified by the cross-linking of CD45. We find that antibody cross-linking of CD3 alone induces a single spike in the vast majority of cells shortly after the addition of the cross-linking antibody. In contrast, cross-linking CD4 alone induces a delayed pattern of repetitive calcium spikes which are decreased in amplitude compared to CD3 cross-linking. Simultaneous cross-linking of CD3 and CD4 induces a sustained increase in intracellular calcium mobilization which is dependent on the presence of extracellular calcium. This sustained increase in intracellular calcium concentration is also seen following physiologic cross-linking of CD3 and CD4 after T cell interaction with specific antigen and antigen-presenting cells. Finally, the simultaneous cross-linking of CD45, CD3 and CD4 abrogates the sustained increase in calcium seen following CD3 and CD4 cross-linking. These results suggest that the qualitative nature of T cell receptor signaling can be modulated by the molecular association of other signaling molecules, which may be part of the T cell receptor complex or not.     

抗人CD28激发性单抗对T细胞淋巴瘤的抑制作用研究

目的:研究鼠抗人CD28单克隆抗体(克隆号:2F5)对T淋巴细胞瘤的抗肿瘤效应,为抗体介导肿瘤靶向治疗提供新的方法和思路。方法:流式细胞术检测鼠抗人CD28单克隆抗体2F5对人T淋巴瘤细胞株Jurkat细胞表面膜型CD28分子的识别;MTT法检测2F5对Jurkat细胞体外增殖的影响;将Jurkat细胞株接种于裸鼠腋下,建立Jurkat细胞荷瘤裸鼠模型;经瘤内多点注射2F5(注射剂量1μg/mm3),逐日观察肿瘤的大小和裸鼠的生存状态。结果:2F5能够识别Jurkat细胞表面CD28分子,阳性结合率可达93.37%;2F5与Jurkat细胞共培养后,显微镜下观察可见胞质中出现黑色颗粒,胞膜破裂,细胞的折光性和立体感减弱;MTT法分析结果显示,抗CD28单抗对Jurkat细胞的体外增殖具有明显的抑制作用;将Jurkat细胞接种35只裸鼠(成瘤率达70%);经瘤内多点注射2F5,35天后荷瘤小鼠体内肿瘤的生长速率明显降低;而生理盐水对照组肿瘤生长无明显改变。结论:鼠抗人CD28单克隆抗体2F5通过与Jurkat细胞表面膜型CD28分子结合对其增殖具有明显的抑制作用,提示CD28分子可作为治疗T淋巴瘤的一个潜在靶点,抗体对治疗CD28分子阳性的肿瘤具有潜在临床应用价值。     

CD8+ CD28- and CD8+ CD57+ T cells and their role in health and disease

Chronic antigenic stimulation leads to gradual accumulation of late-differentiated, antigen-specific, oligoclonal T cells, particularly within the CD8(+) T-cell compartment. They are characterized by critically shortened telomeres, loss of CD28 and/or gain of CD57 expression and are defined as either CD8(+) CD28(-) or CD8(+) CD57(+) T lymphocytes. There is growing evidence that the CD8(+) CD28(-) (CD8(+) CD57(+)) T-cell population plays a significant role in various diseases or conditions, associated with chronic immune activation such as cancer, chronic intracellular infections, chronic alcoholism, some chronic pulmonary diseases, autoimmune diseases, allogeneic transplantation, as well as has a great influence on age-related changes in the immune system status. CD8(+) CD28(-) (CD8(+) CD57(+)) T-cell population is heterogeneous and composed of various functionally competing (cytotoxic and immunosuppressive) subsets thus the overall effect of CD8(+) CD28(-) (CD8(+) CD57(+)) T-cell-mediated immunity depends on the predominance of a particular subset. Many articles claim that CD8(+) CD28(-) (CD8(+) CD57(+)) T cells have lost their proliferative capacity during process of replicative senescence triggered by repeated antigenic stimulation. However recent data indicate that CD8(+) CD28(-) (CD8(+) CD57(+)) T cells can transiently up-regulate telomerase activity and proliferate under certain stimulation conditions. Similarly, conflicting data is provided regarding CD8(+) CD28(-) (CD8(+) CD57(+)) T-cell sensitivity to apoptosis, finally leading to the conclusion that this T-cell population is also heterogeneous in terms of its apoptotic potential. This review provides a comprehensive approach to the CD8(+) CD28(-) (CD8(+) CD57(+)) T-cell population: we describe in detail its origins, molecular and functional characteristics, subsets, role in various diseases or conditions, associated with persistent antigenic stimulation.     

CD28 mRNA rapidly decays when activated T cells are functionally anergized with specific peptide

The induction of non-responsiveness in specific clones of Tcells In vivo might be expected to reverse immunologlcally mediateddisease processes. With this goal in mind, experiments in vitrowith cloned T cells have investigated the mechanisms of inductionof anergy. Resting T cells can be functionally inactivated invitro by high doses of appropriate peptide in either the presenceor absence of antigen presenting cells. During the inductionof anergy, the modulation of the surface phenotype of T cellsis similar to that of cells proliferating in response to animmunogenic stimulus. The amount of T cell receptor at the cellsurface is down regulated, whereas the CD2 and CD25 receptorsare increased in density. in contrast, CD28 has been identifiedas a membrane protein that is differentially regulated duringactivation and the induction of non-responsiveness. Ligatlonof CD28 provides an efficient costlmulatory signal for activationof T cells. In this report, we show that not only resting cells,but also fully activated T cells can be rendered non-responsiveand that this process is accompanied by profound downregulationof CD28, both at the level of cytoplaamic mRNA and surface expressionof the mature protein. This observation anticipates clinicalintervention in immunologically mediated disease, where thetarget T cells are more likely to be activated than in a restingstate.     

Low T cell reactivity to combined CD3 plus CD28 stimulation is predictive for progression to AIDS: correlation with decreased CD28 expression

In 219 HIV-1-infected men of the Amsterdam cohort we measured CD4⁺ T cell numbers and in vitro T cell responses to CD3 MoAbs with or without CD28 costimulation and phytohaemagglutinin (PHA). The value of these markers was estimated for disease progression within 4 years. CD28 expression on T cells has been related to T cell responses. CD28 costimulation considerably enhanced T cell reactivity (≈8–10-fold) with lower coefficients of variation compared with reactivity to CD3 MoAb alone (median 5 versus 20). T cell reactivity to CD3 plus CD28 MoAb was decreased during HIV-1 infection and was besides CD4⁺ T cell numbers the only independent predictor for progression to AIDS. Compared with the group with high CD4⁺ T cell numbers the relative risk (RR) for the group with intermediate levels was 2.28, with low levels 5.20. In the groups with intermediate and low CD3 plus CD28 responses the RR was 2.04 and 4.16, respectively. The combined RR for both was 4.65 and 21.63. The independence of this marker was confirmed when the group with low CD4⁺ T cell numbers was subdivided into groups with high, intermediate and low T cell responses. The expansion of CD8⁺CD28⁻ T cells was already apparent in HIV⁻ homosexual men, but CD8⁺CD28⁺ T cells specifically decreased in patients with AIDS. CD28 expression on T cells correlated moderately with T cell responses to CD3 plus CD28 MoAb. T cell reactivity to CD3 MoAb in the presence of CD28 MoAb is a stronger prognostic marker than T cell reactivity to CD3 MoAb alone.     

Gene expression patterns associated with tumor-infiltrating CD4+ and CD8+ T cells in invasive breast carcinomas

BackgroundBreast carcinoma is one of the most common tumors in women. The immune microenvironment, especially T cell infiltration, is related to the occurrence and prognosis of breast carcinoma.ObjectiveThis study investigated the gene expression patterns associated with tumor-infiltrating CD4+ and CD8+ T cells in invasive breast carcinomas.MethodsThe gene expression data and corresponding clinical phenotype data from the Cancer Genome Atlas Breast Invasive Carcinoma (TCGA-BRCA) were downloaded. The stromal and immune score were calculated using ESTIMATE. The differentially expressed genes (DEGs) with a high vs. low stromal score and a high vs. low immune score were screened and then functionally enriched. The tumor-infiltrating immune cells were investigated using the Cibersort algorithm, and the CD4+ and CD8+ T cell-related genes were identified using a Spearman correlation test of infiltrating abundance with the DEGs. Moreover, the miRNA-mRNA pairs and lncRNA-miRNA pairs were predicted to construct the competing endogenous RNAs (ceRNA) network. Kaplan-Meier (K-M) survival curves were also plotted.ResultsIn total, 478 DEGs with a high vs. low stromal score and 796 DEGs with a high vs. low immune score were identified. In addition, 39 CD4+ T cell-related genes and 78 CD8+ T cell-related genes were identified; of these, 14 genes were significantly associated with the prognosis of BRCA patients. Moreover, for CD4+ T cell-related genes, the chr22-38_28785274-29006793.1–miR-34a/c-5p–CAPN6 axis was identified from the ceRNA network, whereas the chr22-38_28785274-29006793.1–miR-494-3p–SLC9A7 axis was identified for CD8+ T cell-related genes.ConclusionsThe chr22-38_28785274-29006793.1–miR-34a/c-5p–CAPN6 axis and the chr22-38_28785274-29006793.1–miR-494-3p–SLC9A7 axis might regulate cellular activities associated with CD4+ and CD8+ T cell infiltration, respectively, in BRCA.