Pro-inflammatory type-1 and anti-inflammatory type-2 macrophages differentially modulate cell survival and invasion of human bladder carcinoma T24 cells

Findings from numerous studies suggest that inflammation is likely to have an important role in bladder carcinogenesis and cancer disease progression. While macrophages (M?s) constitute a major inflammatory component of the stroma of human bladder carcinoma, the regulatory role of such inflammatory leukocytes in tumor cell survival and invasion remains elusive. Human urothelial bladder cancer (UBC) T24 cells and monocyte-derived macrophages were used to study the relative contribution of pro-inflammatory type-1 (M?-1) and anti-inflammatory type-2 (M?-2) macrophages in the regulation of UBC cell behaviour. Cell-to-cell studies indicated that the number of viable cells were considerable higher in T24 cell/M?-2 cocultures but lower in T24 cell/M?-1 cocultures when compared to cultures of T24 cells alone. M?-1-derived factors inhibit T24 cell growth but fail to induce caspase-3-mediated apoptosis. M?-2-derived factors have the ability to suppress the inhibitory effect of M?-1-derived factors on T24 cell growth. Exogenous interleukin (IL)-10 reverse M?-1-mediated arrest growth in T24 cell/M?-1 cell cocultures. Further analyses showed that M?-1-derived factors induced tumor necrosis factor (TNF)-α gene expression, promoted cellular invasiveness and increased phosphoinositide 3-kinase (PI 3-K)/Akt signaling pathway activity in T24 cells. Inhibition of PI 3-K activation in T24 cells or blockade of TNFα receptor in T24 cell/M?-1 cell cocultures decreased cellular invasiveness but did not affect T24 cell viability. Based on these observations, we propose that similar functional interactions between UBC cells and infiltrating macrophages can take place in vivo and influence tumor cell survival and invasion during bladder cancer progression.     

Phenotypic characterization and functional activity of human milk macrophages

A large population (about 80%) of the cells obtained from colostrum and early human milk were considered to be macrophages by the following criteria: nonspecific esterase stain, adherence, phagocytosis and IgG-Fc receptor expression. The majority of freshly isolated human milk macrophages (HMM phi) stain for the monocyte antigen OKM1. Another monocyte antigen, 61D3, was expressed only by 30% of HMM phi. Class II antigens were expressed by HMM phi. About 85% of the cells were DR-positive whereas 50% were DS-positive as assessed with a panel of monoclonal antibodies directed against class II antigens. Monocyte and class II antigens were gradually lost during in vitro culture. HMM phi can support proliferative response to antigens and mitogens when cocultured with autologous peripheral T cells. The proliferative response was significantly reduced when monoclonal antibodies to DR or DS were added to the assay. These results indicate that HMM phi have the phenotype and functional characteristics of antigen presenting cells.     

CD40-CD40 ligand costimulation is not required for initiation and maintenance of a Th1-type response to Leishmania major infection

Although previous studies demonstrated a requirement for CD40-CD40 ligand (CD40L) interaction in the development of resistance to Leishmania infection, we recently showed that mice lacking the gene for CD40L (CD40L(-/-) mice) can control Leishmania major infection when they are infected with reduced numbers of parasites. In this study, we examine the cytokine pattern in healing versus nonhealing CD40L(-/-) mice and investigated whether CD40 activation is required for resistance to reinfection. We observed that CD4(+) cells in healed CD40L(-/-) mice produce high levels of gamma interferon compared to cells from nonhealing, high-dose-inoculated mice. In addition, we observed a higher frequency of interleukin-12 (IL-12)- producing cells and a reduced number of IL-4-producing cells in mice infected with reduced numbers of parasites. Importantly, we found that healed CD40L(-/-) mice are highly resistant to reinfection with a large parasite inoculum. In addition, by comparing the cytokine patterns at an early and late stage of infection in nonhealing CD40L(-/-) mice, we demonstrated that nonhealing CD40L(-/-) mice produce a weak Th1-type response during the early stage of infection, but this response wanes as a Th2-type response emerges during late stages of infection. Anti-IL-4 antibody treatment, starting either at the beginning of infection or at week 4 postinfection enabled CD40L(-/-) mice to control a high-dose infection. Together, these results show that CD40-CD40L interaction, although important for IL-12 production in high-dose infections, is not required for either the development or maintenance of resistance in mice infected with reduced numbers of parasites.     

Identification of anti-inflammatory drugs according to their capacity to suppress type-1 and type-2 T cell profiles

BACKGROUND: Down-regulation or modulation of T cell activity by immunosuppressive drugs is an effective treatment in diseases where exaggerated T cell responses play a role. A primary effect of the anti-inflammatory drugs (AIDs) is inhibition of the synthesis of growth factors, such as IL-2, thereby down-regulating T cell proliferation. However, it is still largely unknown to what extent these AIDs are able to down-regulate specifically type-1 or type-2 T cell cytokine production, and whether they can down-modulate chemokine receptor expression, thereby preventing migration of T cells to the site of inflammation. OBJECTIVE: We investigated the suppressive effect of dermatologically used AID (cyclosporin A (CsA), lactoferrin (LF), 1 alpha, 25-dihydroxyvitamin D(3) (VD(3)), hydrocortisone (HC), di-methyl-fumarate (DMF), diclofenac (DF)) on both type-1 and type-2 T cells. Since allergic contact dermatitis is a skin disorder in which an exaggerated T cell response of both types of T cell subsets can be observed, we used this disorder as a model to study the capacity of AID to suppress type-1 or type-2 T cell responses. METHODS: Peripheral blood mononuclear cells of nickel allergic patients were cultured in the presence of allergen and increasing concentrations of AID. Proliferation was determined by measuring (3)H thymidine incorporation; chemokine receptor (CCR10, CCR4, CXCR3) expression was studied by flow cytometric analysis and IFN-gamma or IL-5 cytokine production was measured by ELISA. RESULTS: Three major patterns can be distinguished regarding the effect of AID on T cell responses. The first group, including CsA and LF, inhibited non-selectively T cell proliferation, chemokine receptor expression and cytokine production, with CsA as the most potent drug tested. A second group of AID, which included VD(3), HC and DMF, suppressed mainly type-1 T cell responses, as revealed by strong interference with IFN-gamma production and CXCR3 expression, and limited effects on either or both IL-5 and CCR4 expression. The third pattern was displayed by DF, which down-regulated IL-5 production and CCR4 expression, whereas IFN-gamma and CXCR3 were unaltered. CONCLUSIONS: Using a contact allergy model, we have demonstrated that various AIDs show distinct pharmacological profiles in that either type-1 or type-2 or both T cell responses are suppressed. These results should contribute to a more rational selection of AID in treating inflammatory skin diseases mediated by either or both of these T cell subsets.     

Phenotypic and functional heterogeneity of CD169 and CD163 macrophages from porcine lymph nodes and spleen

Secondary lymphoid organ macrophages are involved in the establishment of innate and acquired immunity. Here, we have isolated and characterized porcine lymph node and spleen CD169⁺ and spleen CD163⁺ macrophages. Lymph node and spleen CD169⁺ macrophages can be both identified as CD172a⁺SLA-DR^hiCD80/86^hiCD14^intTLR2⁺TLR4⁺. On the other side, spleen CD163⁺ macrophages are CD172a⁺SLA-DR^intCD80/86^intCD14⁻/^loTLR2^intTLR4^int. In addition, these macrophages can be subdivided based on the expression of CD11R1 or CD11R3. Lymph node CD169⁺ macrophages phagocytozed polystyrene microspheres more efficiently than spleen CD163⁺ and CD169⁺ macrophages. All macrophages exhibited low capacity to take up and process the soluble antigen DQ-OVA. Finally, spleen CD163⁺ macrophages displayed the highest ability to present lysozyme to CD4⁺ T cells in a secondary in vitro response, followed by lymph node and spleen CD169⁺ macrophages.     

Phenotypic and functional characterization of human CD25+ B cells

We demonstrate that humans have a phenotypically and functionally distinct subset of B lymphocytes that express the interleukin (IL)-2 receptor (IL-2R) alpha-chain, cluster of differentiation (CD) 25. We found that one-third of the circulating CD20+ B cells expressed CD25 and, using fluorescence-activated cell sorter (FACS) analysis, that these cells were significantly larger and more granulated than B cells not expressing CD25. The simultaneous expression of the other two subunits (CD122 and CD132) and the proliferative responses of cells expressing CD25 to IL-2 suggested that, in addition to CD25, functional IL-2 receptors were expressed on this cell population. CD25 expression on B cells was selectively up-regulated by Toll-like receptor 2 (TLR2), TLR4, and TLR9 ligands but not by a TLR3 ligand or Epstein-Barr virus (EBV) stimulation. Blockade of the nuclear factor (NF)-kappaB pathway completely abolished CD25 up-regulation by these B cells. Interestingly, CD25+ B cells expressed significantly higher levels of surface immunoglobulins but lacked the ability to secrete immunoglobulin (Ig), as compared with CD25- B cells. Furthermore, CD25+ B cells performed significantly better as antigen-presenting cells in allogeneic mixed lymphocyte reactions (MLR), which may be a result of their expression of high levels of the costimulatory molecules CD27 and CD80. Finally, blocking of CD25 on B cells led to an almost total abrogation of MLR. Our results indicate that CD25+ B cells have distinct phenotypic and functional properties, including the ability to contribute to antigen presentation, which is linked to their expression of CD25. Finally, the differential regulation of CD25 expression via selective TLR ligands suggests a role for CD25+ B cells in bridging innate and acquired immune responses.     

Potentiation by human serum of anti-inflammatory cytokine production by human macrophages in response to apoptotic cells

Phagocytosis of apoptotic cells by macrophages leads to the production of anti-inflammatory cytokines, thereby preventing inflammation. In this study, we demonstrate that human serum potentiates the production of anti-inflammatory cytokines, IL-10 and TGF-beta, by PMA-treated THP-1 cells and human monocyte-derived macrophages in response to apoptotic cells, which results in great suppression of the production of proinflammatory cytokine IL-8. Human IgG but not its F(ab)'(2) suppressed the IL-8 production. Pretreatment of macrophages but not apoptotic cells with human serum or human IgG caused the suppression, suggesting that immune complex may not be formed with apoptotic cells. When FcgammaRI was specifically down-modulated by a monoclonal antibody, M22, the potentiating effects of human serum and human IgG on the anti-inflammatory cytokine production and the suppressive effects on IL-8 production were completely abolished. Thus, human IgG and FcgammaRI appear to be critical in leading to the production of anti-inflammatory cytokines by macrophage in response to apoptotic cells.     

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.     

Specificity of proliferative response of human CD8 clones to mycobacterial antigens

Human CD8 T lymphocyte clones (TLC) were generated from the pleural effusion of patients with tuberculosis using a protocol that required, in addition to antigen, coculture of purified CD8+ T cells, accessory cells, interleukin 2 (IL2) and anti-CD3-Sepharose. The TLC obtained were stimulated by mycobacterial soluble extracts in an IL2-dependent and MHC class I-restricted manner. When antigen-responsive TLC were screened with extracts from the recombinant mycobacterial library they were found to respond to either the Y3125 (100-kDa) or the Y3111 (71-kDa) lambda gt11 clones. Polyacrylamide gel immunoblot analysis demonstrated that the CD8 TLC responded to fractions with the molecular mass range 27-45 kDa in the Y3125 lysogen and 60-90 kDa in the mycobacterial soluble extract. The specificity of TLC reactive with the Y3111 clone was confirmed using the 71-kDa antigen purified from the same lysogen. These TLC recognized sequences common to the 71-kDa protein derived from mycobacteria, E. coli or a human cell line. Studies of three TLC using antigen-presenting cells of known genetic haplotype indicated that stimulation with both the Y3125 and the 71-kDa antigens were restricted by determinants encoded by HLA-B8.     

CD46-mediated costimulation induces a Th1-biased response and enhances early TCR/CD3 signaling in human CD4+ T lymphocytes

The role of membrane cofactor protein (MCP, CD46) on human T cell activation has been analyzed. Coligation of CD3 and CD46 in the presence of PMA or CD28 costimuli enhanced IL-2, IFN-gamma, or IL-10 secretion by CD4+ T lymphocytes. The effect of CD46 on IL-10 secretion did not require additional costimuli like anti-CD28 antibodies or phorbol esters. CD46 also enhanced IL-2 or IFN-gamma secretion by CD4+ blasts. In contrast, IL-5 secretion was inhibited upon CD46-CD3 coligation, in all the cells analyzed. These effects were independent of IL-12 and suggest that CD46 costimulation promotes a Th1-biased response in human CD4+ T lymphocytes. CD46 enhanced TCR/CD3-induced tyrosine phosphorylation of CD3zeta and ZAP-70, as well as the activation of the ERK, JNK, and p38, but did not modify intracellular calcium. The effect of specific inhibitors shows that enhanced ERK activation contributes to augmented IFN-gamma and lower IL-5 secretion and, consequently, to the Th1 bias. Cross-linking CD46 alone induced weak tyrosine phosphorylation of CD3zeta and ZAP-70. However, CD46 cross-linking by itself did not induce cell proliferation or lymphokine secretion, and pretreatment of CD4+ T lymphocytes with anti-CD46 antibodies did not significantly alter TCR/CD3 activation.     

单核细胞在含内毒素的微环境中分化时表型与功能的改变

目的　观察单核细胞在含内毒素 (LPS)的微环境中分化成巨噬细胞时 ,其表型与功能的变化。方法　以含LPS的介质体外培养纯化的正常人循环单核细胞 ,在其分化为巨噬细胞的不同阶段观察形态、超微结构、细胞表面HLA DR、补体 3受体 (C3R)和甘露糖受体 (MR)的表达以及细胞分泌超氧离子 (O-2 )、白细胞介素 1β(IL 1β)和肿瘤坏死因子α(TNF α)的变化。结果　与在自身血清中分化的巨噬细胞相比 ,(1)在含LPS介质中发育的巨噬细胞体积较小 ,但具有正常巨噬细胞的超微结构特征 ;(2 )在分化早期 (第 1天 ) ,其HLA DR的表达明显上调 ,而在成熟阶段 (第 5天 )表达下调。LPS对C3R和MR的表达无明显作用 ;(3)在含LPS介质中分化的巨噬细胞 ,其在佛波醇肉豆蔻乙酸盐刺激下生成O-2 的能力得以保持。自发分泌IL 1β和TNF α的水平明显高于在血清中分化的巨噬细胞。结论　在含LPS微环境中分化的巨噬细胞具有与正常单核细胞衍生的巨噬细胞所不同的功能特征 ,表现为MHCⅡ类抗原的表达降低 ,促炎症介质的生成增加。     

Immunomodulatory effect of a plasmid expressing CD40 ligand on DNA vaccination against human immunodeficiency virus type-1

CD40 ligand is a costimulatory molecule which acts a potent immunomodulator. We found the mice inoculated with human CD40 ligand expression plasmid (pMEhCD40L) combined with human immunodeficiency virus type-1 (HIV-1) DNA vaccine exhibited both humoral and cellular antigen-specific immunological enhancement. The expression of hCD40L induced predominantly antigen-specific immunoglobulin G (IgG) antibody response while it failed to induce mucosal IgA response. Delayed-type hypersensitivity (DTH) and cytotoxic T lymphocyte (CTL) activity were induced in a dose-dependent manner. Examination of the relative levels of the two IgG subclasses showed that co-injection of pMEhCD40L enhanced IgG2a response without suppressing IgG1 response. Similarly, the expression of pMEhCD40L enhanced not only T helper 1 (Th1)- but also Th2-type cytokine production. In conclusion, co-inoculation of pMEhCD40L with DNA vaccine was shown to be a useful way to enhance CTL responses without suppressing the humoral immune response in acquired immune deficiency syndrome (AIDS) patients.     

Phenotypic and functional analysis of human CD3- decidual leucocyte clones.

CD3- leucocyte clones were generated from human first-trimester decidualized uterine endometrium in a culture system containing interleukin-2 (IL-2) and phytohaemagglutinin (PHA). All CD3- clones tested by Southern blot analysis had T-cell receptor (TcR) gamma and delta genes in germ-line configuration. Thirty-six CD3- cell clones obtained from eight decidual samples were mostly CD2+CD56+ but, unlike fresh decidual leucocytes, many were also CD16+. Morphological differences were noted between CD16+CD56+ and CD16-CD56+ clones, with the latter cells possessing granules of more variable size. All CD16+ clones expressed strong cytotoxic activity against natural killer (NK) sensitive and NK-resistant cell targets, while CD16- clones had low or negligible activity. Some CD3- clones produced high levels of interferon-gamma, tumour necrosis factor-negligible activity. Some CD3- clones produced high levels of interferon-gamma, tumour necrosis factor-alpha (TNF-alpha) and transforming growth factor-beta (TGF-beta) upon stimulation, but there was no relationship between specific cytokine production and cell clone phenotype or cytotoxic function. Levels of TGF-beta were generally higher than those produced by decidual CD3+ T-cell clones. Since decidual CD3- CD16- leucocytes have a low proliferative capacity in response to IL-2, and as clones with this phenotype invariably possess low NK cell activity, it is suggested that the NK cell activity of fresh decidual leucocyte populations is mediated largely by the small numbers of CD3- CD16+ cells present.     

Dissociation between interleukin-1 and interleukin-2 production in proliferative response to microbial antigens: restorative effect of exogenous interleukin-2.

The relationship between the production of interleukin-1 (IL-1) and interleukin-2 (IL-2) after stimulation of human mononuclear cells within an antigenic extract from Candida albicans was analyzed in both responder and nonresponder donors. Culture supernatants from responders contained both IL-1 and IL-2 activity, whereas the supernatants from nonresponders contained only IL-1 and no appreciable IL-2. However, the addition of exogenous IL-2 to nonresponder cultures restored the normal proliferative response. Similar observations were made when cells from mice infected intravenously with high doses of Mycobacterium bovis BCG were cultured; these cells showed a marked impairment of the proliferative response to purified protein derivative. Spleen cells from BCG-induced unresponsive mice failed to produce IL-2 despite the fact that normal IL-1 activity was present in the culture. Again, the addition of exogenous IL-2 fully reversed the proliferative unresponsiveness. Thus, the presence of IL-1 does not necessarily induce production of IL-2, and the proliferative unresponsiveness is therefore due to a primary lack of IL-2.     

Increase of CCR1 and CCR5 expression and enhanced functional response to MIP-1 alpha during differentiation of human monocytes to macrophages

Chemokines and their receptors regulate migration of leukocytes under normal and inflammatory conditions. In this study, we analyzed the CC chemokine receptor (CCR) expression of monocytes differentiating in vitro to macrophages. We observed a time-dependent change of expression and functional responsiveness of CCR1, CCR2, and CCR5 within 48 h. Whereas freshly harvested monocytes were strongly attracted by monocyte chemotactic protein 1 (MCP-1), a specific ligand for CCR2, only a weak response was observed to macrophage inflammatory protein 1alpha (MIP-1alpha), which binds to CCR1 and CCR5. In striking contrast, differentiated macrophages displayed a strong chemotactic response to MIP-1alpha and only a weak response to MCP-1. These findings were paralleled by intracellular calcium shifts. During the time course of monocyte to macrophage differentiation, mRNA levels and surface expression of CCR2 decreased, whereas that of CCR1 and CCR5 increased. The time-dependent switch from CCR2 on monocytes to CCR1 and CCR5 on mature macrophages reflects a functional change belonging to the differentiation process of monocytes to macrophages and may form the basis for a differential responsiveness of monocytes and macrophages to distinct sets of chemokines.     

Phenotypic and functional changes in alveolar macrophages contribute to the pathogenesis of pulmonary sarcoidosis.

Bronchoalveolar lavage (BAL) was performed on 10 patients with sarcoidosis and 10 normal volunteers. In each case aliquots of the lavage were used to prepare cytospins on which differential cell counts were performed. Immunocytological methods using monoclonal antibodies RFD1 and RFD7 (identifying dendritic cells and mature macrophages in normal tissues) were performed to identify macrophage subsets. Sarcoid BAL contained a significantly higher proportion of RFD1+ cells (mean 44.7 +/- 10.32% compared to 12.3 +/- 4.0% in normals). Much of this increase was accounted for by a highly significant rise in the proportion of cells with the double phenotype RFD1+/RFD7+ (27.2 +/- 6.1% in sarcoid compared to 7.3 +/- 2.0% in normal). Suspensions of sarcoid and normal BAL were also studied in autologous mixed lymphocyte reactions (AMLR) using peripheral blood mononuclear cells (PBM) as a responder population. AMLRs were therefore set up using BAL, PBM, and BAL with PBM. In each case reactivity was compared to mitomycin treated controls. These studies revealed that sarcoid PBM expressed markedly reduced AMLR reactivity when compared to normal but both sarcoid and normal BAL were relatively unreactive. BAL admixed with PBM suppressed peripheral blood AMLR reactivity in the normals. In sarcoid patients BAL admixed with PBM abolished AMLR completely. We suggest that changes within the BAL macrophage populations in sarcoid patients may significantly influence the pathogenesis of this disease.     

Biological function of CD40 on human endothelial cells: costimulation with CD40 ligand and interleukin-4 selectively induces expression of vascular cell adhesion molecule-1 and P-selectin resulting in preferential adhesion of lymphocytes

The expression of adhesion molecules on vascular endothelial cells determines the pattern of migration and extravasation of leucocytes in inflammation and immunity. Here we show that costimulation with CD40 ligand (CD40L) and interleukin (IL)-4 (or IL-13) gives rise to a unique pattern of adhesion molecule expression by human umbilical vein endothelial cells (HUVEC). CD40 ligation alone enhanced expression of vascular cell adhesion molecule-1 (VCAM-1), intracellular adhesion molecule-1 (ICAM-1) and E-selectin whereas IL-4 and IL-13 increased expression of VCAM-1 and P-selectin but not ICAM-1 or E-selectin. When IL-4 and CD40L were combined there was an additional increase of both VCAM-1 and P-selectin, but ICAM-1 and E-selectin were both inhibited. The combined effects of IL-4 and CD40L signalling were not the result of altered response kinetics, enhanced sensitivity of the endothelium, or increased expression of CD40 or the IL-4 receptor. The rise in VCAM-1 expression induced by combined IL-4 and CD40L stimulation was slower and more sustained than with tumour necrosis factor-alpha (TNF-alpha) and occurred only on a subset (75-80%) of the endothelial cell population compared to 100% with TNF-alpha. Costimulation with IL-4 and CD40L increased adhesion of T cells and B cells above levels obtained with either signal alone, but decreased adhesion of neutrophils. Furthermore, CD40 and IL-4 synergistically increased IL-6 but decreased IL-8 production by HUVEC. These results show that interactions between IL-4 and CD40 on endothelial cells give rise to specific patterns of adhesion molecule expression and cytokine production that may have important implications for lymphocyte and neutrophil migration and function at sites of inflammation.     

Stimulation of cloned human T lymphocytes via the CD3 or CD28 molecules induces enhancement in vascular endothelial permeability to macromolecules with participation of type-1 and type-2 intercellular adhesion pathways.

Perivascular accumulation of CD29+CD45R0+ memory T lymphocytes at sites of chronic inflammation such as rheumatoid synovium is commonly associated with the localized increase in the endothelial permeability. We have recently demonstrated that a direct interaction between activated CD29+CD45R0+ memory T lymphocytes and vascular endothelial cells (EC) results in the increased permeability of EC. In this report, we have investigated effects on antigen-specific T cell receptor (TcR) alpha/beta+ human T lymphocyte clones on the endothelial permeability to albumin. Our results show that CD29+CD45R0+ cloned human T lymphocytes augment endothelial permeability by a noncytolytic process requiring surface contact between T lymphocytes and EC. Both cytolytic and noncytolytic cloned T lymphocytes were capable of augmenting endothelial permeability and this process did not involve active lysis of EC. Stimulation of T lymphocytes via the CD3/TcR or CD28 molecules resulted in significant enhancement in the ability of T lymphocytes to influence endothelial permeability. Pretreatment of T lymphocytes with monoclonal antibodies directed at either CD11a/CD18 (LFA-1) or CD2 molecules or that of EC with monoclonal antibodies directed at either CD54 (ICAM-1) or CD58 (LFA-3) molecules significantly inhibited T lymphocyte-induced enhancement in endothelial permeability, thus indicating that activated T lymphocytes utilize both type-1 (CD11a/CD18CD54) and type-2 (CD2CD58) intercellular adhesion pathways to augment endothelial permeability and signals received via CD3 or CD28 molecules on T lymphocytes further enhance this process. Furthermore, proinflammatory cytokines interleukin 1 and tumor necrosis factor but not proinflammatory cytokines interleukin 1 and tumor necrosis factor but not interleukin 6 induced resistance in EC to T lymphocyte-mediated effects on their permeability. Collectively, these observations may provide insights into molecular mechanism(s) underlying pathophysiology of localized chronic inflammatory responses in general and more specifically selective accumulation of chronically activated memory T lymphocytes at sites of chronic inflammation.     

Interferon produced endogenously in response to CSF-1 augments the functional differentiation of progeny macrophages

The role of endogenously produced interferon alpha/beta in the functional maturation of newly derived mononuclear phagocytes was investigated. Addition of highly specific anti-interferon alpha + beta antiserum to murine marrow cultures stimulated with colony-stimulating factor-1 (macrophage growth factor) markedly suppressed the capacity of resulting progeny mononuclear phagocytes to ingest opsonized sheep erythrocytes (EAIgG). This impairment was corrected either by direct addition of interferon alpha + beta at a concentration in excess of that neutralized by the antiserum or by the addition of lesser amounts of interferon (33 U/ml) following removal of the anti-interferon from the cultures. Conditioned media from control colony-stimulating factor-stimulated cultures similarly reversed the impairment of maturation resulting from 5 days of growth in the presence of anti-interferon. This enhancement of EAIgG ingestion reflected upon the interferon activity in the conditioned media and was neutralized by anti-interferon. Lastly, the endogenous interferon was found to enhance EAIgG ingestion by a majority of the mononuclear phagocyte progeny and not by a limited subpopulation.