The synergistic effects of interleukin 2 and interleukin 7 on the proliferation and autologous tumor cell lysis of tumor-associated lymphocytes

Interleukin-7 (IL-7) has an ability to stimulate the proliferation of pre-B cells. It has been shown that IL-7 can also activate T lymphocytes. We here demonstrate that IL-7 in combination with interleukin-2 (IL-2) can drive cell proliferation and enhance the autologous tumor cell lysis by peripheral blood mononuclear cells (PBMC) and autologous mixed lymphocyte tumor cell culture (MLTC)-derived effector cells (MLTC cells). These synergistic effects of IL-2 and IL-7 on the proliferation and the augmentation of autologous tumor cell lysis were found for both effector cells. These effects were inhibited by neutralizing antibodies to IL-2 or IL-7, and by a combination of both antibodies, significantly. In terms of phenotypical expression, CD3 positive cells comprised the vast majority of MLTC cells after culture in medium containing IL-2 and IL-7 with an increase of IL-2 receptor positive cells.Abbreviations CD cluster differentiation - IFN interferon - IL interleukin - JRU Japanese Reference Unit - LAK lymphokine activated killer - mAb monoclonal antibody - MLTC mixed lymphocyte tumor cell culture - PBMC peripheral blood mononuclear cells - TILs tumor infiltrating lymphocytes     

Antibodies against the CD44 p80, lymphocyte homing receptor molecule augment human peripheral blood T cell activation

The CD44 inhibitor Lutheran [In(Lu)]-related p80 molecule has recently been shown to be identical to the Hermes-1 lymphocyte homing receptor and to the human Pgp-1 molecule. We have determined the effect of addition of CD44 antibodies to in vitro activation assays of PBMC. CD44 antibodies did not induce PBMC proliferation alone, but markedly enhanced PBMC proliferation induced by a mitogenic CD2 antibody pair or by CD3 antibody. CD44 antibody addition had no effect upon PBMC activation induced by PHA or tetanus toxoid. CD44 antibody enhancement of CD2 antibody-induced T cell activation was specific for mature T cells as thymocytes could not be activated in the presence of combinations of CD2 and CD44 antibodies. CD44 antibody enhancement of CD2-mediated T cell triggering occurred if CD44 antibody was placed either on monocytes or on T cells. In experiments with purified monocyte and T cell suspensions, CD44 antibodies A3D8 and A1G3 augmented CD2-mediated T cell activation by three mechanisms. First, CD44 antibody binding to monocytes induced monocyte IL-1 release, second, CD44 antibodies enhanced the adhesion of T cells and monocytes in CD2 antibody-stimulated cultures, and third, CD44 antibodies augmented T cell IL-2 production in response to CD2 antibodies. Thus, ligand binding to CD44 molecules on T cells and monocytes may regulate numerous events on both cell types that are important for T cell activation. Given that recent data suggest that the CD44 molecule may bind to specific ligands on endothelial cells (vascular addressin) and within the extracellular matrix (collagen, fibronectin), these data raise the possibility that binding of T cells to endothelial cells or extracellular matrix proteins may induce or up-regulate T cell activation in inflammatory sites.     

Membrane interactions involved in the induction of acid labile interferon alpha

Human normal peripheral blood mononuclear cells (PBMC) produce acid-labile interferon (IFN) alpha when stimulated in vitro with HIV-infected cells fixed with glutaraldehyde. The cells responsible for IFN production are mainly B lymphocytes. The present study was aimed to further elucidate the cellular source of this IFN and to analyze the membrane interactions involved in the induction process. To this purpose PBMC were stimulated with inducers of acid labile IFN alpha in the presence or absence of a panel of monoclonal antibodies (MoAbs) against antigens of the lymphocyte membrane, namely HLA Class I and II and CD4. The results indicate that both HLA Class II and CD4 antigens are involved in the induction process. Conversely B cell lines seem capable of producing conventional alpha IFN but they fail to produce acid labile IFN alpha even in the presence of cooperating CD4 positive T cell lines. Furthermore PBMC cultured for more than 20 hours prior to stimulation lose the ability to produce acid labile IFN alpha, while remaining fully capable of producing conventional IFN alpha and gamma. It remains to be established whether this phenomenon reflects the disappearance of some membrane structure necessary for acid labile IFN alpha induction, or whether it is due to some early appearing functional alteration of B cells.     

Jaagsiekte retrovirus is widely distributed both in T and B lymphocytes and in mononuclear phagocytes of sheep with naturally and experimentally acquired pulmonary adenomatosis

Jaagsiekte sheep retrovirus (JSRV) is a type D retrovirus specifically associated with a contagious lung tumor of sheep, sheep pulmonary adenomatosis (SPA). JSRV replicates actively in the transformed epithelial cells of the lung, and JSRV DNA and RNA have been detected in lymphoid tissues of naturally affected animals. To determine the lymphoid target cells of JSRV, CD4(+) T cells, CD8(+) T cells, B lymphocytes, and adherent cell (macrophage/monocyte) populations were isolated from the mediastinal lymph nodes of naturally affected sheep and lambs inoculated with JSRV. Cells were enriched to high purity and then analyzed for JSRV proviral DNA by heminested PCR, and the proviral burden was quantitated by limiting dilution analysis. JSRV proviral DNA was found in all subsets examined but not in appropriate negative controls. In sheep naturally affected with SPA, JSRV proviral burden was greatest in the adherent cell population. In the nonadherent lymphocyte population, surface immunoglobulin-positive B cells contained the greatest proviral burden, while CD4(+) and CD8(+) T cells contained the lowest levels of JSRV proviral DNA. In most of the cases (5 of 8), provirus also could be detected in the peripheral blood mononuclear cell (PBMC) population. A kinetic study of JSRV infection in the mediastinal lymphocyte population of newborn lambs inoculated with JSRV found that JSRV proviral DNA could be detected as early as 7 days postinoculation before the onset of pulmonary adenomatosis, although the proviral burden was greatly reduced compared to adult natural cases. This was reflected in the levels found in PBMC since proviral DNA was detected in 2 of 13 animals. At the early time points studied (7 to 28 days postinoculation) no one subset was preferentially infected. These data indicate that JSRV can infect lymphoid and phagocytic mononuclear cells of sheep and that dissemination precedes tumor formation. Infection of lymphoid tissue, therefore, may play an important role in the pathogenesis of SPA.     

Interleukin-2-induced production of interferon-gamma by resting human T cells and large granular lymphocytes: requirement for accessory cell factors, including interleukin-1

Between 5 and 20% of normal human lymphocytes were found to synthesize interferon-gamma (IFN-gamma) in primary cultures with recombinant interleukin-2 (rIL-2). After 22 hr, IFN-gamma-producing cells included CD5+ T lymphocytes, CD16+ large granular lymphocytes (LGL), and a population of CD5-, CD16- blast cells. Only a small proportion (0-7%) of IFN-gamma-synthesizing cells expressed HLA-DR. The production of IFN-gamma by all rIL-2-responding lymphocyte subsets was shown to require the presence of DR+ accessory cells, probably including nonadherent, esterase-negative monocytes and/or dendritic cells. Accessory cell function in lymphocyte preparations depleted of DR+ cells, or in purified (greater than or equal to 95%) suspensions of LGL, was fully replaced either by addition of 2% autologous, adherent monocytes or by monocyte culture supernatant. The activity of monocyte supernatant was greatly reduced by treatment with antiserum specific for human interleukin-1 beta (IL-1 beta), although a combination of rIL-1 beta and rIL-2 failed to stimulate IFN-gamma production in DR- lymphocytes. These results indicate that rIL-2-induced IFN-gamma synthesis in both T cells and LGL requires the synergistic activity of IL-1, and possibly of one or more other monokines, as yet unidentified.     

Lymphocyte function-associated antigen (LFA-1) is involved in B cell activation

Human LFA-1 is a widely expressed leukocyte antigen present on cells of myeloid and lymphoid lineage. Monoclonal antibodies to LFA-1 have been shown to inhibit in vitro T cell immune functions. However, a role for LFA-1 in B cell activation has not been documented. To investigate this possibility, we examined the distribution of LFA-1 on normal, neoplastic, and EBV-transformed B cells as well as the ability of a monoclonal anti-LFA-1 antibody (NB-107) to inhibit B cell mitogenesis. NB-107 immunoprecipitates a noncovalently linked heterodimer of approximately 170,000 and 95,000 daltons. Sequential immunoprecipitation and cross-blocking studies showed that NB-107 identified a distinct epitope on the LFA-1 molecule. NB-107-defined LFA-1 was present on peripheral blood mononuclear cells (PBMC) from all normal individuals (N = 27) and on EBV-transformed cell lines (N = 9), but was absent from four of seven neoplastic B lymphoma lines. NB-107 was observed to profoundly inhibit the response of PBMC to the B cell mitogens anti-IgM (mean 71% inhibition) and lipopolysaccharide (mean 80% inhibition). In order to investigate the mechanism of inhibition, B cells were sequentially purified from PBMC by using a combination of E rosette depletion of T cells, monocyte removal by glass adherence, and finally cell sorting. These extensively enriched populations of B cells, although still responding to anti-mu, showed no evidence of inhibition by NB-107. Growth of EBV-transformed cell lines, cultured in the presence of NB-107, also was not inhibited by this antibody. When tested in assays for T cell function, NB-107 was shown to inhibit the mixed lymphocyte response, but had no effect on phytohemagglutinin stimulation of PBMC nor on the clonal growth and differentiation of granulopoietic, erythropoietic, and pluripotent progenitor cells. We conclude that anti-LFA-1 monoclonal antibody inhibits B cell mitogens via indirect effects on monocytes and/or T cells, rather than by a direct antiproliferative effect on B cells.     

The hyaluronate receptor is a member of the CD44 (H-CAM) family of cell surface glycoproteins [published erratum appears in J Cell Biol 1991 Feb;112(3):following 513]

The present study was undertaken to determine the relationship between the hyaluronate receptor and CD44 (H-CAM), cell-surface glycoproteins of similar molecular weights that have been implicated in cell adhesion. In initial experiments, a panel of monoclonal antibodies directed against CD44 were tested for their ability to cross react with the hyaluronate receptor. These antibodies immunoprecipitated [3H]hyaluronate binding activity from detergent extracts of both mouse and human cells, indicating that the hyaluronate receptor is identical to CD44. In addition, one of these antibodies (KM-201 to mouse CD44) directly blocked the binding of labeled hyaluronate to the receptor and inhibited hyaluronate dependent aggregation of SV-3T3 cells. CD44 has also been implicated in lymphocyte binding to high endothelial venules during lymphocyte homing. Interestingly, the monoclonal antibody Hermes- 3, which blocks lymphocyte binding to the high endothelial venules of mucosal lymphoid tissue, had no effect on the binding of labeled hyaluronate. Furthermore, the binding of lymphocytes to high endothelial cells of lymph nodes and mucosal lymphoid tissue was not significantly affected by treatment with agents that block the binding of hyaluronate (hyaluronidase, excess hyaluronate and specific antibodies). Thus, CD44 appears to have at least two distinct functional domains, one for binding hyaluronate and another involved in interactions with mucosal high endothelial venules.     

Nectin-3 (CD113) Interacts with Nectin-2 (CD112) to Promote Lymphocyte Transendothelial Migration

Lymphocyte trafficking and migration through vascular endothelial cells (ECs) in secondary lymphoid tissues is critical for immune protection. In the present study, we investigate the role of nectin cell adhesion molecules for the migration of lymphocytes through ECs. Nectins are key players for the establishment of homotypic and heterotypic cell to cell contacts; they are required for cell to cell adherens junction formation and take part in the transendothelial migration of monocytes during the step of diapedesis, when monocytes migrate through EC junctions. We first show that Nectin-3 (CD113) is the only nectin expressed by T lymphocytes and since nectins are expressed on ECs we explored Nectin-3 potential functions in lymphocyte: EC interactions. We demonstrate that Nectin-2, expressed on ECs, is the major counter-receptor of Nectin-3. A soluble form of Nectin-3 binds to Nectin-2 localized at EC junctions and blocking Nectin-2 trans-interactions with monoclonal antibodies abolishes the binding of soluble Nectin-3 to ECs. Nectin-2 is expressed on High Endothelial venules (HEVs), where lymphocyte homing occurs in vivo. Finally, we show that Nectin-3 trans-interaction with Nectin-2 is essential for the process of lymphocyte transendothelial migration in vitro as targeting with blocking monoclonal antibodies either Nectin-3, expressed on lymphocytes, or Nectin-2, expressed on ECs, inhibits lymphocyte extravasation. The nectin family of CAMs is important for the regulation of endothelial barrier functions and transendothelial migration of immune cells. Our results demonstrate for the first time that Nectin-3 trans-interacts with Nectin-2 to promote lymphocyte and monocyte extravasation.     

Human dendritic reticulum cells of lymphoid follicles: their antigenic profile and their identification as multinucleated giant cells

The B-dependent areas of human lymphoid tissue contain non-lymphoid, non-phagocytic cells known as dendritic reticulum cells (DRC). These cells can be detected only very occasionally in routinely stained histologic sections. Recently we were able to overcome this limitation by preparing a monoclonal antibody, termed R 4/23, that reacts selectively with DRC. Thus by using an optimized immunoperoxidase method applied to frozen sections, it is possible to detect DRC in situ. To determine the antigenic profile of DRC, serial frozen sections of human tonsils were immunostained with R 4/23 and a large panel of other monoclonal antibodies or conventional antisera. In addition, touch imprints of tonsils and cytocentrifuge slides of cell suspensions with increased concentrations of DRC were immunostained with these reagents. DRC proved to be positive for mu, gamma, alpha, kappa and lambda chains, complement component C3b, C3b receptors, C3d receptors, HLA-A,B,C antigens, human Ia-like antigens, common ALL antigen (cALLa), and antigens that are characteristic of the monocyte/macrophage lineages. DRC did not express delta chains, T cell antigens, or antigens that are expressed on interdigitating reticulum cells (IDC) and Langerhans cells. DRC in touch imprints and suspensions prepared from hyperplastic tonsils were found to be giant cells often with 10 or more nuclei. In certain cases of follicular hyperplasia and of centroblastic-centrocytic lymphoma, DRC with several nuclei were also detectable in situ. These results show that (1) the phenotype of DRC differs from that of all other cell types in lymphoid tissue, (2) this phenotype most nearly resembles that of cells of the monocyte/macrophage series, thus suggesting that DRC are related to these cell lineages, and (3) DRC are multinucleated giant cells.     

Multiple myeloma: an immunologic profile. IV. The EA rosette-forming cell is a Leu-1 positive immunoregulatory B cell

Patients with myeloma have a depressed capacity to respond to antigenic challenge. Studies in this laboratory have previously described an unclassified lymphoid cell which binds human erythrocytes coated with human immunoglobulin G (IgG) anti-D antibody (EA) as important in the inhibition of Ig synthesis in myeloma patients. Using monoclonal antibodies, two-color fluorescence studies, and flow cytometry, we characterized this EA cell as a Leu-1+ (cluster designation (CD) 5), Leu-12+ (CD 19), Leu-16+ (CD 20), B2+ (CD 21), Leu-14+ (CD 22), and HLA-DR+ B cell. The cell was negative for antibodies to Leu-2 (CD 8), Leu-3 (CD 4), Leu-4 (CD 3), Leu-5 (CD 2), Leu-7, Leu-8, Leu-11 (CD 16), Leu-M1 (CD 15), Leu-M3, and CALLA (CD 10). This profile is consistent with a Leu-1+ B cell and excludes a T cell, natural killer cell, and monocyte. Comparison of the relative role of these cells to the role of monocytes in the suppression of pokeweed mitogen-stimulated Ig synthesis was determined in serial studies on 19 myeloma patients. The mean (+/- SEM) percentage of inhibition of Ig synthesis by monocytes from stage I myeloma patients was 14 +/- 2.2%, from stage II patients was 37 +/- 3.5%, and from stage III patients was 51 +/- 4.7%. Inhibition of Ig synthesis by Leu-1+ EA cells was 46 +/- 1.5%, 48 +/- 1.6%, and 43 +/- 3.7% in stage I, II, and III patients, respectively. Immunosuppressive B cells are an important component of inhibition of Ig synthesis in the immunodeficiency of myeloma.     

The distribution of peripheral blood dendritic cells assayed by a new panel of anti-BDCA monoclonal antibodies in healthy representatives of the polish population

A growing number of studies are being performed on the role of dendritic cells (DCs) in the etiopathogenesis of various conditions. Therefore, it is extremely important to establish the best comparable methods for the determination of the absolute count of blood dendritic cells (BDCs) or their subsets, and the reference normal values for comparisons. The aim of our study was to assess a normal profile of BDCs in the non-cultured human blood of healthy Polish volunteers. BDCs were detected among peripheral blood mononuclear cells (PBMC) from 99 healthy people, aged 18-56. Based on the panel of novel anti-BDCA1, BDCA2 and BDCA3 monoclonal antibodies (MoAbs), three main subpopulations of BDCs were distinguished: two myeloid types of BDCs, MDC1(BDCA-1+/ CD11c+ /HLA-DR+) or MDC2 (BDCA-3+/CD32-/CD64-/HLA-DR+), and a plasmacytoid subtype, PDC (BDCA-2+/CD123+/HLA-DR+). The number and percentage of BDCs were correlated with the age, gender, photosensitivity (phototype, minimal erythemal dose -- MED) and morphological parameters of the healthy volunteers. BDCs represented 0.83% of the PBMC and the median total BDC number was 44.0 cell/microl. The total BDC number correlated with the WBC count (rho=0.40, p=0.001) as well as with the lymphocyte and monocyte counts (rho=0.20, p=0.045 and rho=0.26, p=0.009, respectively). The median percentage of the MDC1 count (0.20%) was twice as high as the MDC2 count (0.10%). The median PDC count was 28.2 cell/microl, and these cells represented 0.50% of the PBMC. There was a positive correlation between PDC and skin photosensitivity (rho=0.28, p=0.005). An inverse correlation between the PDC count and the age of the examined volunteers was also found (rho=-0.22, p=0.029). Our study provides the first referential data on normal rates and counts of BDCs and their subpopulations, assessed by the new panel of anti-BDCA MoAbs, in healthy Polish subjects. The method used in the study allowed the determination of BDCs and their subset numbers in a relatively small blood volume.     

Distribution of ecto-5'-nucleotidase on subsets of human T and B lymphocytes as detected by indirect immunofluorescence using goat antibodies

Human T and B lymphocyte subsets were characterized for ecto-5'-nucleotidase (ecto-5'-NT) expression by two-color immunofluorescence by using polyclonal goat antibodies to 5'-NT and murine monoclonal antibodies to T and B cell subsets. Anti-5'-NT antibodies were prepared by immunizing a goat with purified human placental 5'-NT. Lymphocyte surface 5'-NT was detected with F(ab')2 fragments of immune goat IgG followed by biotinylated F(ab')2 rabbit anti-goat IgG and fluorescein isothiocyanate-avidin. Lymphocyte cell surface antigens were detected with phycoerythrin (PE)-conjugated anti-CD3, anti-CD4, anti-CD8, anti-CD16, and anti-CD19. HB-4, an antigen present on a major subset of human peripheral blood B cells, was detected with murine monoclonal anti-HB-4 and PE-anti-mouse-kappa. Analysis showed that ecto-5'-NT was expressed on 32 +/- 7% of CD3+, 19 +/- 6% of CD4+, and 50 +/- 21% of CD8+ T cells, but not on CD16+ lymphocytes. Ecto-5'-NT was also expressed on 81 +/- 8% of adult peripheral blood B cells as defined by PE-anti-CD19; HB-4 was expressed on 84 +/- 7% of CD19+ cells. The two populations of B cells were not identical, however, because HB-4 was co-expressed on only 79 +/- 18% of ecto-5'-NT+ B cells. Two-color immunofluorescent staining of T cells from a patient with congenital agammaglobulinemia and low T cell ecto-5'-NT activity revealed reduced percentages of ecto-5'-NT+ cells in his CD3+, CD4+, and CD8+ populations. Thus, reduced ecto-5'-NT activity by enzyme assay was paralleled by reduced numbers of 5'-NT molecules on the cell surface. Two-color immunofluorescent staining of B cells from a patient with hypogammaglobulinemia and low B cell ecto-5'-NT activity also revealed markedly reduced expression of 5'-NT. HB-4 expression was normal, however, suggesting that the patient's B cells were blocked in maturation subsequent to the acquisition of HB-4 but prior to that of ecto-5'-NT. These results demonstrate that anti-5'-NT antibodies will be valuable tools for analyzing ecto-5'-NT expression and lymphocyte maturation in patients with immuno-deficiency diseases.     

Isolation of monocytes from human peripheral blood using immuno-affinity expanded-bed adsorption

A novel technique for the separation of monocytes from human peripheral blood preparations has been developed. The technique is based on the use of expanded-bed adsorption and a solid perfluorocarbon derivatized with avidin or streptavidin for the indirect positive or negative capture of cells labeled with biotinylated monoclonal antibodies. The perfluorocarbon support was prepared and characterized and the contactor design and operating conditions, that enable cells to be selectively isolated, were investigated. Experiments consisted of applying an immunolabeled pulse of 1 x 10(8) peripheral blood mononuclear cells (PBMCs), isolated by density gradient centrifugation, directly onto a refrigerated expanded bed. The major cell types remaining were T-lymphocytes, B-lymphocytes, and monocytes. Monocytes could be positively adsorbed, following labeling with anti-CD14 mAb, with a clearance of up to 89% and a depletion factor of 7.6. They could also be "eluted" using mechanical shear, with a 77% yield of the applied cells at a purity of 90% and >/= 65% viability. Negative isolation of monocytes, following labeling of the other cells present with anti-CD2, CD7, CD16, CD19, and CD56 mAbs, resulted in lymphocyte depletions of up to 81% with a monocyte enrichment factor of 3.8 and purity of 71%. The monocyte viability in the flowthrough was assessed to be > 95%. This combination of expanded-bed adsorption and fluidizable affinity supports shows significant potential for the intensification of cell separations.     

Binding of human lymphocyte-specific monoclonal antibodies to common marmoset lymphoid cells

Commercially available monoclonal antibodies which bind to human lymphocyte subsets were screened for their ability to bind to lymphoid cells from the common marmoset Callithrix jacchus. Anti-Leu-5 and T11 were the only pan T-cell antibodies which reacted strongly. None of the antibodies which bind human lymphocytes of the helper/inducer subpopulation reacted with C. jacchus cells and only one antibody, T8, specific for the cytotoxic/suppressor subset, bound to the marmoset cells. The two antibodies tested which bind human B cells, B1 and anti-HLA-DR, were also reactive with marmoset cells. The cellular specificity of the T11, T8, and B1 antibodies was determined by dual binding studies on the fluorescence-activated cell sorter. The B1 antibody bound only Ig+ cells and all Ig+ cells were B1+. The T11 and T8 antibodies bound only to Ig- marmoset lymphoid cells and, as in the human, all T8+ marmoset cells were also T11+. Thus, using these monoclonal antibodies in the common marmoset one can identify three populations of lymphoid cells: (1) T11+, T8+ cells; (2) T11+, T8- cells; (3) B1+ cells.     

Malignant pleural effusions due to small cell carcinoma of the lung. An immunocytochemical cell-surface analysis of lymphocytes and tumor cells

Thirteen malignant pleural effusions due to small cell carcinoma (SCC) of the lung were immunocytochemically studied using the peroxidase-antiperoxidase adhesive slide assay for the determination of cell surface antigens. A panel of monoclonal antibodies (MAbs) was used to determine the lymphocyte subpopulations and the reactivity of the tumor cells. Of the lymphocytes, 87 +/- 1% were CD3+ T cells, with 72 +/- 10% CD4+ helper/inducer T cells and 20 +/- 5% CD8+ suppressor/cytotoxic T cells. Only a minority of T lymphocytes were activated in terms of expressing the surface markers CD38 and HLA-DR. The distribution of the lymphocyte subpopulations was not significantly different from the distribution in other malignant and nonmalignant pleural diseases previously studied, indicating that the reaction pattern of the lymphocytes in the pleural cavity is similar in different diseases. The tumor cells from all cases were positive for LeuM1, CD16 and HLA-DR; 10 of 11 cases were positive for HEA-125, Sam 2 and Sam 10. Positivity for epithelial membrane antigen was observed in 11 cases, for OKT9 in 8 cases and for carcinoembryonic antigen in 6 cases. A total or partial loss of the reactivity with HLA-1 was found in nine cases. The reactivity pattern of the tumor cells with the MAbs used in this study is not specific for SCC of the lung because other carcinoma cells also reacted with these markers. Additional morphologic criteria, such as cell size and cell configuration, are needed to recognize the immunocytochemically positive-reacting cells as tumor cells from SCC of the lung. However, the immunostaining allows a better identification of the tumor cells, especially in cases with a small quantity of tumor cells.     

Monoclonal antibody-defined surface markers of effector cells involved in human monocyte cytotoxicity

Human adherent peripheral blood mononuclear cells were cytotoxic in vitro against the murine TU5 line in a 48-hr [3H]thymidine-release assay. Monocyte-enriched adherent cell preparations contain a small and variable (usually less than 5%) contamination with large granular lymphocytes as assessed by morphology and staining with monoclonal antibody markers B73.1 and HNK1. To assess whether killing was in fact mediated by monocytes, mononuclear cells or monocyte-enriched preparations were separated using monoclonal antibodies directed against mononuclear phagocytes (Mo2, UCHM1, B44.1) or natural killer (NK) cells (B73.1 and HNK1), and a fluorescence-activated cell sorter. Cells positive for monocyte markers were highly cytotoxic against TU5, whereas negative cells were not. B73.1+ or HNK1+ cells had little or no activity. Cytotoxicity of cells positive for monocyte markers (Mo2, UCHM1, B44.1) was augmented by in vitro exposure to lymphokines or less frequently to interferon (IFN). However, cells negative for these monocytes markers were also stimulated to kill TU5 by lymphokine or IFN to an extent similar or greater than that of positive ones. IFN or lymphokines induced killing of TU5 by monocyte-depleted, B73.1-positive, lymphoid cells. These observations demonstrate that human monocytes do kill tumor cells, either in the absence of deliberate stimulation or after exposure to agents such as lymphokines. However, the possible contribution to "monocyte" cytotoxicity of minor NK cell contaminants must be taken into account particularly when agents such as IFN and lymphokines are applied, even when a relatively NK-cell-resistant target such as TU5 is used.     

Human lymphokine-activated killer (LAK) cells: identification of two types of effector cells

We analyzed the antigenic phenotype of lymphokine-activated killer (LAK) effector cells. Human blood lymphocytes were cultured for 3 days with 100 U/ml recombinant interleukin 2 (rIL 2), subpopulations isolated with monoclonal antibodies and a fluorescence-activated cell sorter (FACS) and assayed for cytotoxic activity against 51chromium labeled noncultured melanoma tumor cells. Initial experiments compared the LAK effector function of CD5+ T lymphocytes vs CD5- cells (predominantly CD16+ NK cells). The mean percent specific release at a 10:1 effector:target (E:T) ratio was 25% +/- 16 for CD5- cells, 10% +/- 6 for CD5+ cells, and 22% +/- 9 for unsorted cells. In contrast, when lymphocyte subpopulations were isolated before rIL 2 culture (LAK precursors), CD5- cells but not CD5+ cells developed LAK activity (28% +/- 12 vs 1% +/- 1, mean percent specific release, 10:1 E:T ratio), confirming our previous results showing that only CD16+ cells were LAK precursors. The discrepancy between LAK effector and precursor phenotypes suggested that LAK precursors acquired CD5 determinants during rIL 2 culture; however, double label immunofluorescence of rIL 2 cultured CD16+ cells showed that this was not the case. The data suggested that in the presence of other cell types, some T lymphocytes may develop LAK activity, but purified blood T lymphocytes do not develop LAK function when cultured with rIL 2 alone. We also analyzed LAK effector function in lymphocyte subpopulations defined by CD4 and CD8 antigens. The data showed that lymphocytes with a low density expression of CD8 and no expression of CD4 were enriched for LAK effector cells, whereas CD4+ and CD8- had less activity than unsorted cells. Lymphocytes with a high density expression of CD8 had activity similar to unsorted cells. We also assessed the contribution of Leu-7 (HNK-1) granular lymphocytes to LAK effector function. After culture with IL 2, lymphocytes were depleted of Leu-7+ cells by antibody and complement treatment and then were sorted into CD5+ and CD5- fractions. The cytotoxic activity of Leu-7-CD5+ cells was a mean 5% +/- 5 vs a mean 14% +/- 8 for the total CD5+ population (20:1 E:T ratio). The activity of Leu-7- CD5- was slightly less than the total CD5- fraction (21% +/- 9 vs 28% +/- 14, 10:1 E:T ratio). In conclusion, LAK effector function was highest in non-T cell (CD5- CD16+) populations and some activity was also present in T cell populations (CD5+ and predominantly Leu-7+).     

Influence of aging on intracellular free calcium and proliferation of mouse T-cell subsets from various lymphoid organs.

The influence of aging on T-cell activation and proliferation was examined in lymphocytes derived from peripheral blood, spleen, and lymph nodes of WBB6F1 C57B1/6J x WB/Re) mice. Following activation with anti-CD3 monoclonal antibodies, the greatest age-related changes were seen in CD4+ cells derived from spleens of 27- to 30-month-old mice. These CD4+ lymphocytes showed reduced [Ca2+]i signaling and decreased proliferation in the presence of exogenous interleukin 2. CD8+ cells from spleens of old animals showed reduced [Ca2+]i but not altered proliferation. Both CD4+ and CD8+ cells derived from peripheral blood of old mice showed decreased peak [Ca2+]i, but no defect in cell proliferation. In contrast, age-related deficits in either [Ca2+]i or proliferation were not observed in CD4+ and CD8+ cells from lymph nodes. Additionally, the percentage of CD4+ cells was decreased in all lymphoid organs from old mice, while the percentage of CD8+ cells was similar in lymphoid organs of old and young mice. Old mice had a significant increase in expression of Pgp-1 in CD4+ cells from spleen and peripheral blood and CD8+ cells derived from lymph node. Our studies indicate that there are differential effects of aging in T lymphocytes derived from different lymphoid organs in mice. Among the cell sources and subsets examined, the age-related changes noted in CD4+ cells from mouse peripheral blood were the most similar to those previously observed in the corresponding peripheral blood lymphocyte subset in humans.     

人体胸腺和周围淋巴器官内T细胞亚群和NK细胞分布的研究

本文用多种Ｔ细胞和ＮＫ细胞单抗和免疫组织化学的ＡＢＣ技术,在冰冻切片上对人扁桃体、淋巴结、牌和胸腺内Ｔ细胞亚群和ＮＫ细胞的分布进行了检测。结果显示,ＣＤ５、ＣＤ８、ＣＤ４、ＣＤ３和ＡＩＧ３阳性细胞主要分布在扁桃体,淋巴结的副皮质区、脾的动脉周围淋巴鞘和胸腺,但各种抗体的反应强度不同。从各种Ｔ细胞工群的染色强度和形状看,胸腺髓质部的胸腺细胞相当于周围淋巴器官内的胸腺依赖区。胸腺内Ｔ细胞在分化过程中,质膜上的抗原也有相应变化。ＮＫ细胞主要分布在淋巴小结的生发中心,淋巴结和扁桃体的副皮质区,脾的红髓以及胸腺的筋质部。这些不同的分布,说明ＮＫ细胞不仅与淋巴小结的活动有关,可能还参与机体的免疫调节功能。     

Immunologic monitoring studies in advanced cancer patients treated with recombinant human gamma interferon (IFN-gamma 4A)

Thirty-nine patients with a variety of advanced malignancies were treated with recombinant IFN-gamma 4A (AMGen, specific activity 1 to 5 x 10(7) U/mg protein). IFN-gamma 4A was administered at a dose of 10-2,000 micrograms/m2/d. Following a 2-week rest, a maintenance phase was continued with injections 3 d/wk. Immunologic monitoring studies were performed on patients' peripheral blood cells before administration of IFN-gamma 4A, then on Days 15 and 90. Flow cytometric analysis was used to determine the absolute number of CD 3+, CD 4+, CD 8+, CD 19+, and CD 16+ cells using a panel of monoclonal antibodies. Natural killer (NK) cell function was assayed by monitoring lysis of the K562 cell line in the Cr51 release assay. Changes from baseline were observed on Days 15 and 90 in all parameters studied, although the ratio of helper to suppressor cells seemed to remain within the normal range. Whereas there were no substantial changes in CD 3+ and CD 4+ cells on Day 15, IFN-gamma 4A had an enhancing effect on CD 8+, CD 19+, and CD 16+ cells. This trend continued at Day 90 only for CD 19+ and CD 16+ cells at the higher dose levels. An increase in functional NK cell activity at Day 15 was less noted on Day 90. Comparison of intravenous (IV) to intramuscular-subcutaneous (IM-SC) administration showed differences in the effect on lymphocyte subpopulations at 450 and 1,000 micrograms. The effect of IFN-gamma 4A on the equilibrium among lymphocyte subpopulations and the possibility of its role in combination therapy with other biologic response modifiers are discussed.