Interleukin-7 administration alters intestinal intraepithelial lymphocyte phenotype and function in vivo

BACKGROUND: Interleukin-7 (IL-7) plays a crucial role in controlling T-cell development and homeostasis. IL-7 knock out and IL-7 receptor knock out mice show distinct declines in absolute numbers of the intestinal intraepithelial lymphocytes (IEL). Therefore, we hypothesized that exogenous administration of IL-7 would alter IEL phenotype and function. METHODS: Adult C57BL/6J mice were treated with IL-7 or saline. Mice were euthanized at day 7. Cytokine and keratinocyte growth factor (KGF) expressions were measured with RT-PCR. IEL phenotype was studied with flow cytometry. Finally, to address the association of endogenous epithelial cell (EC)-derived IL-7 and IEL, confocal microscopy was used to observe co-localization of IL-7 to IEL subpopulations. RESULTS: IL-7 administration significantly increased IEL numbers. CD8alphabeta+ IEL increased 3.2-fold, CD8+CD44+ IEL increased 1.3-fold, and alphabeta-T-cell receptor (TCR)+ IEL increased 1.3-fold. IL-7 administration also significantly changed both alphabeta-TCR+ IEL- and gammadelta-TCR+ IEL-derived cytokine expressions. Interestingly, IL-7 administration also led to a significant increase in KGF expression. Confocal microscopy showed a high level of co-localization between the alphabeta-TCR+ IEL and EC-derived IL-7. gammadelta-TCR+ IEL showed a lower level, but still significant, co-localization. CONCLUSION: IL-7 administration significantly affected IEL phenotype and function. The observed co-localization suggests that there is a close IEL-EC cross-communication mediated by EC-derived IL-7 expression.     

肠道菌群对肠黏膜T淋巴细胞亚群的调节作用

肠道菌群在肠道免疫稳态中起到了至关重要的作用。大量研究表明肠道菌群通过调节T淋巴细胞亚群的增殖、分化和T细胞亚群分泌不同的细胞因子,可以改变肠道免疫系统的状态。本研究综述了肠道微生物对主要T淋巴细胞亚群的调节作用。     

Regulatory function for murine intraepithelial lymphocytes. Two subsets of CD3+, T cell receptor-1+ intraepithelial lymphocyte T cells abrogate oral tolerance

The murine intraepithelial lymphocyte (IEL) population is enriched in T cells that express the gamma delta-TCR, however, the biologic function served by these T cells remains obscure. IEL are considered to be major effector cells in mucosal immunity, and we have investigated whether IEL subsets could reverse orally induced systemic unresponsiveness (oral tolerance; OT) and support secondary type responses when adoptively transferred to mice orally tolerized with SRBC. When purified CD3+ IEL from mice orally primed with SRBC were transferred to adoptive hosts and challenged with SRBC, splenic IgM, IgG1, IgG2b, and IgA anti-SRBC plaque-forming cell responses were observed. However, CD3+ IEL from HRBC orally primed mice did not abrogate SRBC induced OT. Further, HRBC-primed CD3+, IEL converted HRBC-specific OT but not SRBC-specific OT. CD3+ IEL could be separated into four subsets based on expression of CD4 and CD8. CD3+, CD4-, 8+ T cells were the major subset (74.5%), with smaller numbers of CD4- and CD8- (double negatives, DN) (7.8%), CD4+, 8- (7.6%) and CD4+, CD8+ (double positives) (10.1%) T cells. Interestingly, both the CD3+, CD8+, and the CD3+, DN IEL subsets abrogated OT, resulting in significant IgM, IgG1, IgG2b, and IgA anti-SRBC plaque-forming cell responses when adoptively transferred to mice with OT. However, neither CD3+, CD4+, CD8-, nor double positive T cells affected OT when studied in this system. The CD3+, CD8+ IEL subset could be further separated into Thy-1+ (16.6%) and Thy-1- (83.4%) cells; adoptive transfer of Thy-1- cells abrogated oral tolerance whereas the Thy-1+ subset was without effect. When the expression of TCR on IEL with this biologic function was determined by use of monoclonal anti-alpha beta TCR (H57.597), TCR2-, CD3+ IEL possessed immunoregulatory function whereas the alpha beta-TCR+ (TCR2+) fraction did not abrogate OT. Immunoprecipitation of membrane fractions obtained from purified CD3+, CD4-, CD8+, Thy-1- IEL with polyclonal anti-delta peptide (Tyr-Ala-Asn-Ser-Phe-Asn-Asn-Glu-Lys-Leu) antibody revealed bands of 45 and 35 kDa, corresponding to the delta- and gamma-chains, respectively. These results suggest that gamma delta-TCR+ IEL possess a regulatory function, namely the restoration of immune responses in a state of oral tolerance. Further, both CD3+, CD4-, CD8+, Thy-1-, and CD3+, DN IEL T cells exhibit this effector contrasuppressor function.     

Differential effects of cadmium on blood lymphocyte subsets

This work was designed to analyze the possible dose dependent effects of cadmium on the blood lymphocyte subset distribution and if these effects are related to circulating cadmium concentration. For that purpose, adult male rats were exposed for one month to 0, 5, 10, 25, 50 or 100 ppm of cadmium chloride (CdCl2) in the drinking water. B lymphocytes decreased in peripheral blood with the doses of 5 and 10 ppm of CdCl2. From the dose of 25 ppm on, B cells increased. T lymphocytes were increased with the doses of 25, 50 and 100 ppm of CdCl2. The lower doses of the metal induced opposite effects. CD4+ and CD8+ cells decreased with the doses of 5 and 10 ppm whereas they were increased with the dose of 25 ppm of CdCl2 on. From the dose of 10 ppm on, cadmium concentration was increased. The results on the distribution of blood lymphocyte subsets suggest that cadmium inhibits the humoral and cellular immune response with the lower doses of the metal used, and opposite effects were detected with the higher doses, the effect not being dependent on the circulating cadmium.     

Regulation of human intestinal intraepithelial lymphocyte cytolytic function by biliary glycoprotein (CD66a).

Human small intestinal intraepithelial lymphocytes (iIEL) are a unique population of CD8alphabeta+ TCR-alphabeta+ but CD28- T lymphocytes that may function in intestinal epithelial cell immunosurveillance. In an attempt to define novel cell surface molecules involved in iIEL function, we raised several mAbs against activated iIELs derived from the small intestine that recognized an Ag on activated, but not resting, iIELs. Using expression cloning and binding studies with Fc fusion proteins and transfectants, the cognate Ag of these mAbs was identified as the N domain of biliary glycoprotein (CD66a), a carcinoembryonic Ag-related molecule that contains an immune receptor tyrosine-based inhibitory motif. Functionally, these mAbs inhibited the anti-CD3-directed and lymphokine-activated killer activity of the P815 cell line by iIELs derived from the human small intestine. These studies indicate that the expression of biliary glycoprotein on activated human iIELs and, potentially, other mucosal T lymphocytes is involved in the down-regulation of cytolytic function.     

Specific overexpression of IL-7 in the intestinal mucosa: the role in intestinal intraepithelial lymphocyte development

IL-7 plays a crucial role in controlling T cell development and homeostasis. Since IL-7 may be derived from extraintestinal sources, and exogenous IL-7 broadly affects lymphoid populations, the actions of epithelial cell (EC)-derived IL-7 are not fully understood. The effect of intestinal specific expression of IL-7 on intestinal mucosal lymphocytes was investigated by using an IL-7 transgenic mouse model. We generated an intestinal EC-specific overexpressing IL-7 transgenic mouse model (IL-7(vill)) and compared their phenotype and function to wild-type C57BL/6J mice. EC-derived IL-7 overexpression was found to be exclusively in the small and large intestine. Numbers and subtypes of mucosal lymphocytes, including intraepithelial lymphocytes (IEL) and lamina propria lymphocytes (LPL), significantly changed in IL-7(vill) mice. From a functional standpoint, IEL proliferation also significantly increased in IL-7(vill) mice. IEL cytokine expression significantly changed in both T cell receptor (TCR)-alphabeta(+) and TCR-gammadelta(+) IEL subpopulations, including a significant increase in IFN-gamma and TNF-alpha as well as an increase in keratinocyte growth factor expression. EC expression of CD103 (integrin alpha(E)beta(7)), the ligand of E-cadherin, markedly upregulated and may account for a mechanism of the massive expansion of IEL in transgenic mice. Systemic lymphoid populations did not change in transgenic mice. IL-7 overexpression by intestinal EC significantly affected IEL phenotype and function. These results offer insight into the role of IL-7 in IEL development and suggest a critical role of EC-derived expression of IL-7 in the phenotype and function of IEL.     

Regulation and function of cyclin D2 in B lymphocyte subsets

Abs produced by B lymphocytes play an essential role in humoral immunity against pathogens. This response is dependent upon the extent of genome replication, which in turn allows clonal expansion of Ag-specific B cell precursors. Thus, there is considerable interest in understanding how naive B cells commit to genome replication following Ag challenge. The BCR is a key regulator of B cell growth responses in the bone marrow and the periphery. The importance of identifying BCR-coupled signaling networks and their cell cycle targets is underscored by the recognition that aberrant cell cycle control can lead to lymphoproliferative disorders or lymphoid malignancies. This review focuses on recent progress toward understanding the function of cyclin D2 in cell cycle control, and in the development of murine B lymphocytes.     

Differential expression of H-Y antigen on lymphocyte subsets: analysis by flow cytometry

Expression of H-Y antigen in human white blood cells was measured using flow cytometry with monoclonal antibodies. In this system, lymphocytes were stained preferentially in the male, and to a lesser extent in the female. Analysis of the lymphocyte subsets with biotinylated H-Y antibody conjugated with streptavidin-fluorescein isothiocyanate (FITC) and subset-specific antibody conjugated with phycoerythrin derivative (RD1) revealed differential expression of H-Y among the subsets of the male. In samples from eight men, 41.1% +/- 21.7% of B cells (B1) were stained, compared with 20.7% +/- 12.8% of cytotoxic-suppressor T cells (T8) and 5.4% +/- 3.0% of helper-inducer T cells (T4). In samples from seven women, 12.4% +/- 10.9% of B cells were stained, but staining of T cells was negligible.     

Detection and characterization of cytotoxic T lymphocyte precursors in the murine intestinal intraepithelial leukocyte population

Highly purified preparations of intraepithelial leukocytes (IEL) were obtained from the small intestinal mucosa. Leukocytes from the lamina propria (LPL) were isolated and phenotypically compared with IEL to verify that IEL were minimally contaminated by LPL. Because approximately 80% of IEL expressed the Lyt-2 antigen usually associated with cytotoxic/suppressor T lymphocytes, we wished to determine if precursors for cytotoxic T cells were present in this population. In order to generate cytotoxic cells, IEL and spleen cells from CBA/J mice (H-2k) were co-cultured with irradiated allogeneic spleen cells (H-2d or H-2b) in a one-way mixed leukocyte reaction (MLR). Four to six days later, the cultured cells were assayed against 51Cr-labeled H-2d or H-2b tumor or Con A-stimulated lymphoblast target cells, and the specificity of alloantigen-stimulated IEL and spleen cells was compared. The cytotoxic cells derived from both tissues displayed antigen-specific lysis of the allogeneic targets. Treatment of effector cells, generated from intraepithelial or splenic precursors, with monoclonal antibodies against Thy-1.2, Lyt-1.1, or Lyt-2.1 antigens plus complement, decreased cytotoxicity 85 to 100%, even though only 20 to 50% of the cells were lysed. The alloantigen specificity and surface antigen phenotype of the cultured IEL cells were identical to those of spleen cells and allowed us to conclude that IEL contained a cytotoxic T lymphocyte precursor (CTLp). Further characterization showed that, like spleen, the intraepithelial CTLp was Thy-1+ and Lyt-1+ and their sedimentation velocity was the same but differed from intraepithelial natural killer cells. Although 80% of IEL were Lyt-2+, the frequency of CTLp in the IEL population was estimated to be threefold to fivefold lower than in spleen, and the Lyt-2+ cells were shown not to be an enriched source of CTLp. Thus, the function of the majority of the IEL is still not known. However, there exists within this population CTLp, which may be capable of being stimulated with luminal antigens.     

Diurnal variation of lymphocyte subsets identified by monoclonal antibodies.

Monoclonal antibodies specific for lymphocyte subsets were used to examine circulating lymphocytes obtained at frequent intervals from healthy subjects. A diurnal rhythm was found in the total numbers of lymphocytes, T cells, inducer/helper cells, suppressor/cytotoxic cells, Ia positive cells, and B cells. The lowest levels of all subsets were seen at 0900 hours and the highest levels at 2100. In some subjects the ratio of helper to suppressor cells varied considerably during the sample period, though the ratio was relatively constant for the group as a whole.     

变应性鼻炎患者肠道微生态变化及其与T淋巴细胞亚群的关系

探讨变应性鼻炎患者肠道微生态变化及其与T淋巴细胞亚群的关系。

回顾性分析2019年4月至2020年4月医院收治的64例变应性鼻炎患者的资料, 记为A组; 另回顾性分析同期在该院体检的58例健康者的资料, 记为B组。对比A组和B组研究对象肠道菌群多样性和丰富度的变化, 对比A组和B组研究对象血清T淋巴细胞亚群水平, 分析变应性鼻炎患者肠道菌群相对丰度与血清T淋巴细胞亚群水平的相关性。

A组研究对象肠道菌群Chao1指数和Shannon指数均低于B组(P < 0.05), A组肠道菌群门水平拟杆菌门、变形菌门、厚壁菌门的相对丰度均高于B组(P < 0.05), 放线菌门的相对丰度低于B组(P < 0.05), 属水平毛螺菌属、链球菌属的相对丰度均高于B组(P < 0.05), 肠球菌属、双歧杆菌属、棒状杆菌属的相对丰度均低于B组(P < 0.05)。主成分分析显示2组菌群样品均能明显分开, 横纵坐标的贡献率分别为48.9%和16.7%, 两坐标轴总共解释了不同细菌群落差异的65.6%, 2组群落结构差异明显(P < 0.05)。A组CD3⁺比例、CD4⁺比例和CD4⁺/CD8⁺比值高于B组(P < 0.05), CD8⁺比例低于B组(P < 0.05);采用Pearson相关性检验, 变应性鼻炎患者肠道菌群门水平拟杆菌门、变形菌门和厚壁菌门的相对丰度分别与CD3⁺、CD4⁺比例和CD4⁺/CD8⁺比值呈正相关(P < 0.05), 分别与CD8⁺比例呈负相关(P < 0.05), 放线菌门的相对丰度分别与CD3⁺、CD4⁺比例和CD4⁺/CD8⁺比值呈负相关(P < 0.05), 与CD8⁺比例呈正相关(P < 0.05);属水平毛螺菌属和链球菌属的相对丰度分别与CD3⁺、CD4⁺比例和CD4⁺/CD8⁺比值呈正相关(P < 0.05), 分别与CD8⁺比例呈负相关(P < 0.05), 肠球菌属、双歧杆菌属和棒状杆菌属的相对丰度分别与CD3⁺、CD4⁺比例和CD4⁺/CD8⁺比值呈负相关(P < 0.05), 分别与CD8⁺比例呈正相关(P < 0.05)。

变应性鼻炎患者肠道菌群多样性降低, 门、属水平菌群比例均发生改变, 菌群结构差异明显, 血清CD3⁺、CD4⁺水平和CD4⁺/CD8⁺比值升高, CD8⁺水平降低, 变应性鼻炎患者肠道菌群相对丰度与血清T淋巴细胞亚群水平相关。

     

肠道微生物与2型糖尿病患者T淋巴细胞亚群和炎症因子水平的相关性

探究肠道微生物与2型糖尿病（T2DM）患者T淋巴细胞亚群和炎症因子水平的相关性。

选择2019年4月到2022年4月我院收治的94例T2DM患者作为T2DM组,另选体检健康者81例作为对照组,采集所有受试者外周血及粪便样本,检测空腹血糖（FPG）、胰岛素抵抗指数（HOMA-IR）、空腹胰岛素（FINS）、炎症因子IL-6、hs-CRP水平、T淋巴细胞亚群（CD3⁺、CD4⁺、CD8⁺）水平和主要肠道菌群丰度,分析主要肠道菌群变化与CD4⁺/CD8⁺、IL-6、hs-CRP的关系。

治疗后T2DM组FBG、FINS、HOMA-IR、IL-6、hs-CRP水平均高于对照组（P＜0.05）,T2DM组CD3⁺、CD4⁺、CD8⁺及CD4⁺/CD8⁺比值均低于对照组（P＜0.05）。T2DM组肠道双歧杆菌、乳酸杆菌数量、B/E值低于对照组,大肠杆菌、肠球菌数量高于对照组（P＜0.05）。Pearson相关性分析显示：T2DM患者双歧杆菌、乳酸杆菌、B/E值与IL-6、hs-CRP水平呈负相关,与CD4⁺/CD8⁺比值呈正相关（P＜0.05）;大肠杆菌、肠球菌数量与IL-6、hs-CRP水平呈正相关,与CD4⁺/CD8⁺比值呈负相关（P＜0.05）。

T2DM患者肠道菌群失调、定植力受损,这可能与其能引发患者CD4⁺/CD8⁺水平降低和炎症因子IL-6、hs-CRP水平升高有关。

     

Leucoagglutinin induces differential proliferation of lymphocyte subsets

In this study we have established culture conditions that allow the preferential and rapid expansion of either T cell receptor (TCR)⁺/CD3⁺16^? T lymphocytes or TCR^?/CD3^?16^? natural killer (NK) cells, or the non-selective outgrowth of both subsets. Optimal proliferation of lymphocytes was obtained using a combination of irradiated allogeneic peripheral blood lymphocytes (PBL) and irradiated Epstein Barr virus (EBV) transformed lymphoblastoid B cell lines (B-LCL). Addition of 1μg/ml leucoagglutinin to the culture medium induced a preferential outgrowth of TCR^?/CD3^?16^? T lymphocytes. The proportion of TCR^?/CD3^?16^? NK cells was decreased to 5% or less, although still a 2000-fold multiplication of TCR^?/CD3^?16^? NK cells was obtained at day 13. Without leucoagglutinin a 1000-fold increase of about 70% pure TCR^?/CD3^?16^? NK cells was obtained at day 13. Intermediate concentrations of leucoagglutinin (0.1–0.3μg/ml) resulted in a non-selective expansion of both NK cells and T cells. Irrespective whether leucoagglutinin was added or not, the number of TCR⁺/CD3⁺8⁺ lymphocytes increased more rapidly relative to the TCR⁺/CD3⁺4⁺ lymphocytes resulting in an increased TCR⁺/CD3⁺8⁺ population size. Also under limiting dilution conditions leucoagglutinin increased the frequency of proliferating cells. In contrast to the preferential outgrowth of TCR⁺/CD3⁺8⁺ lymphocytes in bulk cultures, approximately 80% of the clones generated was TCR⁺/CD3⁺4⁺, demonstrating a growth promoting effect of TCR⁺/CD3⁺4⁺ lymphocytes on TCR⁺/CD3⁺8⁺ lymphocytes in PBL bulk cultures.     

Leucoagglutinin induces differential proliferation of lymphocyte subsets

In this study we have established culture conditions that allow the preferential and rapid expansion of either T cell receptor (TCR)+/CD3+16- T lymphocytes or TCR-/CD3-16+ natural killer (NK) cells, or the non-selective outgrowth of both subsets. Optimal proliferation of lymphocytes was obtained using a combination of irradiated allogeneic peripheral blood lymphocytes (PBL) and irradiated Epstein Barr virus (EBV) transformed lymphoblastoid B cell lines (B-LCL). Addition of 1 microgram/ml leucoagglutinin to the culture medium induced a preferential outgrowth of TCR+/CD3+16- T lymphocytes. The proportion of TCR-/CD3-16+ NK cells was decreased to 5% or less, although still a 2000-fold multiplication of TCR-/CD3-16+ NK cells was obtained at day 13. Without leucoagglutinin a 1000-fold increase of about 70% pure TCR-/CD3-16+ NK cells was obtained at day 13. Intermediate concentrations of leucoagglutinin (0.1-0.3 micrograms/ml) resulted in a non-selective expansion of both NK cells and T cells. Irrespective whether leucoagglutinin was added or not, the number of TCR+/CD3+8+ lymphocytes increased more rapidly relative to the TCR+/CD3+4+ lymphocytes resulting in an increased TCR+/CD3+8+ population size. Also under limiting dilution conditions leucoagglutinin increased the frequency of proliferating cells. In contrast to the preferential outgrowth of TCR+/CD3+8+ lymphocytes in bulk cultures, approximately 80% of the clones generated was TCR+/CD3+4+, demonstrating a growth promoting effect of TCR+/CD3+4+ lymphocytes on TCR+/CD3+8+ lymphocytes in PBL bulk cultures.     

Numerical alterations of ageing B lymphocyte subsets

The global population is ageing. Elderly people suffer from more severe infections than younger persons. The major reason for the increased susceptibility to infections in the elderly is the deregulated functions of the immune system. Immunosenescence affects both innate and adaptive immune reactions. Among these, quantitative alterations of B lymphocyte subsets determine outcome of infections and vaccination. The overall number of B cells seems to be stable or the decrease is moderate. Reduced input of naive B lymphocytes is compensated by anergic, exhausted memory cells. Concerning B lymphocyte subsets, experimental data obtained in the mouse model and in vivo studies conducted in old-age humans are frequently controversial. Further analysis of human B lymphocyte subpopulations is required that could be regarded as an important biomarker of human life span.     

EGNA-specific LIF production of human lymphocyte subsets

Using the indirect leukocyte migration inhibition technique T cells have been identified as being responsible for Epstein-Barr virus nuclear antigen-induced specific leukocyte migration inhibitory factor production. The response was dependent on the presence of macrophages or their product, T-lymphocyte activating factor.