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H B Herscowitz

Publications and source records attributed to H B Herscowitz.

At least 19 recordsLinked to original sources
PubMed2001

Ex vivo cytokine activation of peripheral blood stem cells: a potential role for adoptive cellular immunotherapy.

Ex vivo activation of peripheral blood stem cells (PBSC) using interleukin-2 (IL-2) results in cytotoxic effector cells that may possess beneficial in vivo effects. We proposed to evaluate ex vivo stimulation of PBSC using various cytokines alone or in combination to optimize their function. Cytokine-activated PBSC were analyzed for tumor-directed cytotoxicity and their ability to remove tumor cells from long-term clonogenic assays. Mononuclear cells were obtained from the apheresis products of normal donors and cultured with IL-2 (1000 U/ml), interferon-alpha (IFN-alpha) (1000 U/ml), or IL-12 (50 U/ml) either alone or in combinations at 37 degrees C and 5% CO(2) for 24 h. Colony-forming unit-tumor (CFUT) assays were initiated using cytokine-activated PBSC with varying concentrations of MCF-7 or SKBR-3 human breast cancer cells. Standard 4-h (51)Cr-release assays were performed with cytokine-activated PBSC using MCF-7 or SKBR-3 cells as targets. Activation of PBSC with IL-2, IFN-alpha, or IL-12 resulted in enhanced cytotoxicity against the two breast cancer cell lines when compared to controls. PBSC activated with IL-2 and IFN-alpha or IL-2 and IL-12 were more cytotoxic than PBSC activated with single cytokines (p = 0.0004 for MCF-7 cells and p < 0.001 for SKBR-3 cells). Using clonogenic assays, IL-2-activated PBSC reduced the number of CFU-T to a greater extent than did IL-12 or IFN-alpha-activated PBSC (p = 0.0006). However, PBSC activated with a combination of IL-2 and IFN-alpha or IL-2 and IL-12 demonstrated 95% and 90% reductions, respectively, compared to 79% reduction using IL-2-activated PBSC (p < 0.0001). The greatest reduction in cytotoxicity occurred in the cell populations depleted of CD56(+) cells (p = 0.016) and CD8(+) CD56(+) cells (p = 0.002), suggesting that the effector cell population includes a combination of cytotoxic CD8(+) T cells and CD56(+) natural killer cells. These results demonstrate that the ex vivo activation of PBSC with cytokines, either alone or in combination, enhances cytotoxicity against, and removal of two human breast cancer cells. The combinations of IL-2 with IFN-alpha or IL-12 are most beneficial in cytotoxicity and purging assays. These results could play an important role in designing adoptive cellular immunotherapy clinical trials in the autologous hematopoietic stem cell transplant setting.

Blood Component Removal↗
PubMed1999

Systemic antitumor immunity in experimental brain tumor therapy using a multimutated, replication-competent herpes simplex virus.

Replication-competent, attenuated herpes simplex virus (HSV) vectors have been developed for viral oncolytic therapy of primary and metastatic malignant brain tumors. However, the role of the host immune responses in the brain has not been elucidated. N18 neuroblastoma cells were used as a tumor model in syngeneic A/J mice to test the therapeutic efficacy of G207, a conditionally replicating HSV vector, in an immunocompetent condition. G207 inoculated intraneoplastically exhibited a prominent oncolytic antitumor effect in mice harboring N18 tumors in the brain or subcutaneously, and, in addition, elicited a systemic antitumor immune response. Subcutaneous tumor therapy with G207 caused regression of a remote, established tumor in the brain or in the periphery, which was potentially mediated by the systemic antitumor immune response, and provided persistent tumor-specific protection against N18 tumor rechallenge in the brain as well as in the periphery. Antitumor immunity was associated with an elevation of specific CTL activity against N18 tumor cells that persisted for at least 13 months. The results suggest that the oncolytic antitumor action of replication-competent HSV may be augmented by induction of specific and systemic antitumor immunity effective both in the periphery and in the brain.

Animals↗
PubMed1999

Paclitaxel vs cyclophosphamide in peripheral blood stem cell mobilization: comparative studies in a murine model.

Paclitaxel is a promising drug for the treatment of breast and ovarian cancer. It also may play a role in mobilization of peripheral blood stem cells (PBSC), as an alternative to cyclophosphamide (Cy). We investigated the PBSC-mobilizing potential of paclitaxel compared to Cy in a murine model. C57B1/6 mice were primed with intraperitoneal injections of Cy (200 mg/kg) or paclitaxel (60 mg/kg) and were sacrificed 4, 6, 8, or 10 days later. Spleens were harvested and processed to obtain low-density mononuclear cells that were used as PBSC. The number of hematopoietic progenitors (CFU-C) on day 4 was significantly higher in the paclitaxel group when compared to mice receiving Cy (72.0 +/- 1.8 vs 9.8 +/- 2.8, p < 0.001). By day 6, CFU-C became significantly higher in the Cy-treated group compared to the paclitaxel-treated group (195.6 +/- 31.9 vs 95.8 +/- 20.7, p < 0.05) and this trend was maintained. However, the total number of CFU-C recovered per spleen was greater in the paclitaxel-treated group (1.27 x 10(5) +/- 0.53 x 10(5) vs 1.06 x 10(5) +/- 0.36 x 10(5), NS). In contrast to paclitaxel, mobilization with Cy was associated with marked perturbation in the proportion of lymphoid cell subsets in the PBSC population along with functional impairment of lymphocytes. After 24 hours of in vitro IL-2 activation, the cytotoxic effector cell function of the Cy-mobilized PBSC population was lower than that of paclitaxel-mobilized cells when tested against three tumor cell lines (B16, melanoma; C1498, AML; and Yak-1, lymphoma). These results indicate that paclitaxel is an efficient mobilizer of PBSC, leading to early (day 4 to 6) mobilization of PBSC when compared to Cy (day 6 to 8). In addition, paclitaxel was associated with less perturbation of phenotypic and functional characteristics of cells contained within the mobilized PBSC population.

Animals↗
PubMed1995

Phenotypic and functional heterogeneity of the murine alveolar macrophage-derived cell line MH-S.

We have previously reported that MH-S, an established murine alveolar macrophage-derived cell line, mediated profound inhibition of in vitro antibody production, as did their freshly isolated alveolar macrophage (AM) counterparts. In this communication we show that like freshly recovered AMs, the MH-S cell line also displays phenotypic and functional heterogeneity. Sorting of parental MH-S cells by flow cytometry based on reactivity with anti-Mac-1 antibody yielded two subsets. Further analysis by staining with monoclonal antibodies against well-characterized murine macrophage cell surface markers revealed that both Mac-1+ and Mac-1- subsets expressed the mature murine macrophage antigen (F4/80) and class II major histocompatibility complex molecules, but with different intensity. In contrast, the two subsets stained equivalently with antibody against the Fc gamma II receptor, whereas neither subset stained with anti-CD4 antibody. Examination by light microscopy revealed plemorphism in the Mac-1+ population with many of the cells appearing spindle shaped and having elongated processes, whereas a majority of the cells in the Mac-1- population were spherical in shape. Functionally, cells from the Mac-1+ population were less inhibitory of in vitro antibody production and produced significantly more nitric oxide in response to stimulation with lipopolysaccharide than were cells in the Mac-1- population. Essentially similar results were obtained using cloned Mac-1+ and Mac-1- MH-S cells. The finding of heterogeneity in an established cell line that displays functions similar to those of freshly recovered AMs suggests that distinct subsets of AMs may be involved in the pathogenesis of disease processes in the lung.

Animals↗
PubMed1993

Suppression of murine IgM, IgG, IgA and IgE antibody responses by alveolar macrophages.

Freshly recovered pulmonary alveolar macrophages (AM) and the AM-derived established cell line, MH-S, have previously been shown to be highly suppressive of in vitro IgM anti-sheep erythrocyte (SRBC) responses. Supernatants obtained from cultures of AM incubated with antigen-stimulated lymphocytes or from the MH-S cell line alone have also been shown to be suppressive when added to the in vitro antibody-forming system. In order to determine if AM and MH-S cells, owing to their mucosal location, could differentially regulate antibody responses including immunoglobulin isotypes other than IgM, an in vitro system for the detection of cells producing IgG, IgA and IgE anti-2,4 dinitrophenol (DNP) antibody was developed. These studies demonstrate that AM, MH-S cells, and MH-S culture supernatants suppress the in vitro generation of IgM, IgG, IgA and IgE anti-DNP spot-forming cells (SFC). No apparent differential regulation of any of the four murine IgG anti-DNP antibody subclasses was observed. Time-course experiments suggested that optimal AM- and MH-S-mediated suppression occurred 18 hr after culture initiation. Both AM and MH-S cells suppressed IgM and IgG anti-DNP antibody responses in a dose-related manner, suggesting that MH-S is a good model for the study of AM-mediated immunoregulation.

2,4-Dinitrophenol↗
PubMed1989

MH-S, a murine alveolar macrophage cell line: morphological, cytochemical, and functional characteristics.

A continuous cell line of murine alveolar macrophages (AM), designated MH-S, has been established following transformation of cells obtained by bronchoalveolar lavage from Balb/cJ mice with simian virus 40 (SV40). Thirty days after infection of the AM cultures, foci of rapidly proliferating cells were recovered and these have been propagated continuously for more than 36 mo. Following its initial isolation in Fischer's medium supplemented with L-cell-conditioned medium and horse and fetal bovine serum, the cell line is now routinely grown in RPMI-1640 medium containing 10% fetal bovine serum in the absence of conditioned medium. MH-S cells were adherent, lacked contact inhibition, and were trypsin-sensitive. They expressed intracellular T-antigen and incorporated 3H-thymidine (DNA synthesis) with a doubling time of approximately 48 h but doubled in number in 96 h. MH-S exhibited typical macrophage morphology, was greater than 98% esterase-positive, negative for peroxidase, and expressed cell surface Ia and Mac-1 antigens. The cells were Fc receptor-positive as demonstrated by rosette formation with, and phagocytosis of, antibody-coated sheep erythrocytes. Constitutive IL-1 secretion was significantly increased following stimulation of the cells with lipopolysaccharide. Like freshly isolated AM, MH-S cells suppressed the in vitro plaque-forming cell (PFC) response in a dose-dependent manner when cultured with splenic lymphocytes. This cell line should facilitate studies where homogeneous populations of AM are desirable, especially those involved in determining the immunological functions of AM and their potential role in lung pathology.

Animals↗
PubMed1988

Cell interactions in alveolar macrophage-mediated suppression of the immune response: an unusual suppressor pathway involving a population of T-cells that express Lyt-1, L3T4, and I-J.

Studies from this laboratory have demonstrated that incubation of murine alveolar macrophages (AM) with SRBC-primed spleen cells (SC) results in suppression of the in vitro plaque-forming cell (PFC) response and that suppression is mediated by a soluble factor contained in supernatants obtained from cultures of AM and SC. In the present study, immunological techniques employing monoclonal antibody (MoAb) were used to isolate various T-cell subsets in order to determine the phenotype of the cells which interact with AM to produce suppression. Spleen cell populations depleted of Thy-1+-, Lyt-1+-, L3T4+-, or I-J+-bearing cells failed to generate suppressive supernatants when cultured with AM. Depletion of Lyt-2+ T-cells (the classical suppressor/effector subset) did not alter the ability of the remaining cell population to cooperate with AM for generation of suppressive supernatants. Direct suppression of the PFC response in cultures containing AM was abrogated after treatment of the spleen cells with anti-I-J, but not anti-Lyt-2 MoAbs. Reconstitution of the AM-mediated suppressive response with enriched populations of SC required the presence of T-cells which expressed Lyt-1, L3T4, and I-J. These results suggest the existence of an unusual suppressor pathway involving I-J restriction but which appears to be mediated by the interaction of AM with a population of T-cells that expresses surface markers characteristic of T-helper cells.

Animals↗
PubMed1988

A modified in situ enzyme-linked immunosorbent assay for quantitating interleukin-2 activity employing monoclonal anti-IL-2 receptor antibody.

The IL-2R ELISA recently described by Igietseme and Herscowitz (J. Immunol. Methods 97 (1987) 123) is a simple and reliable procedure for measuring the immunological activation of lymphocytes based on the expression of the early activation antigen, the interleukin-2 receptor (IL-2R). In the present report, this assay has now been adapted for the quantitation of IL-2 in culture supernatants and is based on the measurement of augmentation of IL-2R expression resulting from the exposure of sensitive cells (IL-2-dependent T cell line, CTLL-2, and mitogenic blasts) to IL-2. Under the conditions of these experiments, the magnitude of IL-2R expression appears to be directly proportional to the concentration of IL-2 in a given sample up to an optimum concentration beyond which no further increase in IL-2R expression is observed. Dose-response curves revealed that the assay correlates well with the proliferative response of the responder cells as measured by the [3H]thymidine (3H-TdR) uptake assay which is the commonly employed assay for quantitating IL-2. Using a simple mathematical formula, units of IL-2 activity could be assigned to unknown IL-2 preparations employed in these studies based on the activity contained in a standard IL-2 preparation. In an attempt to further simplify the procedure, a novel approach involving an in situ assay was designed and was found to be applicable for quantitating IL-2 by both the 3H-TdR uptake assay and the IL-2R ELISA. The assay can provide direct information about the immediate effect(s) of ligand-to-receptor binding and/or the effect(s) of ligand on the initial response of the cell. The assay could be adapted to quantitate the interleukins, in general.

Animals↗
PubMed1988

The role of membrane gangliosides in murine alveolar macrophage-mediated suppression of the immune response.

Generation of aldehydes on cell membranes of viable alveolar macrophages (AM) by mild oxidation with sodium periodate was previously shown to result in total abrogation of AM-mediated suppression of the plaque-forming cell (PFC) response of spleen cells previously primed with sheep erythrocytes (SRBC). These results suggested a possible role for macrophage sialoglycoconjugates, such as gangliosides and sialoglycoproteins, in suppression. In the present report, it is shown that a purified mixture of gangliosides suppressed the PFC response of SRBC-primed spleen cells in a dose-dependent manner. Addition of rabbit anti-mouse brain antiserum (RAMB), which reacts with the gangliosides, reversed both ganglioside- and AM-mediated suppression of the PFC response. Pretreatment of AM but not spleen cells with RAMB also resulted in the reversal of AM-mediated suppression. The expression of gangliosides on the membrane of AM was detected with RAMB in an enzyme-linked immunosorbent assay (ELISA). The results suggest that membrane gangliosides may play an important role in the AM-mediated suppression of the PFC response. Since paraformaldehyde-fixed AM were not suppressive, it is speculated that AM release the suppressive gangliosides into the culture medium and rabbit anti-mouse brain antibody either prevents their release and/or neutralizes the suppressive function of released gangliosides.

Animals↗
PubMed1988

Role of activation in alveolar macrophage-mediated suppression of the plaque-forming cell response.

Alveolar macrophages (AM) are highly suppressive of the in vitro plaque-forming cell (PFC) response of spleen cells obtained from mice primed with sheep erythrocytes. Comparison of macrophage populations obtained from disparate anatomical sites revealed that although in both cases there was a cell-concentration-dependent suppression of the PFC response, resident AM or AM activated as a result of intravenous injection of Mycobacterium bovis BCG were equally suppressive at the doses examined. Although there was a similar dose-dependent suppression with peritoneal macrophages, BCG-activated cells were more suppressive of the PFC response than were resident cells. In contrast, splenic macrophages at comparable concentrations were not at all suppressive. Resident AM exhibited significantly lower levels of 5'-nucleotidase activity than did resident peritoneal macrophages. Macrophage-mediated suppression of the in vitro PFC response could not be attributed to the release of toxic oxygen metabolites (H2O2, O2- ,and .OH) or prostaglandins, since the addition of catalase, superoxide dismutase, 2-mercaptoethanol, or indomethacin did not completely reverse suppression. These results suggest that the lung microenvironment may maintain AM in an activated state which contributes to their potential immunoregulatory functions.

5'-Nucleotidase↗
PubMed1988

Relationship between ineffective antigen presentation by murine alveolar macrophages and their immunosuppressive function.

Murine alveolar macrophages (AM) have been shown to be inefficient at providing accessory function for initiation of the in vitro plaque-forming cell (PFC) response. In the present study AM, which were obtained either from untreated mice (resident AM) or mice injected i.v. with BCG (activated AM) potently suppressed the PFC response of spleen cells from animals previously primed with sheep erythrocytes (SRBC). Addition of AM at a concentration of 10% with respect to spleen cells resulted in greater than 90% suppression of the PFC response. In order to determine if inefficient antigen presentation was associated with AM-mediated suppression, the role of IL-1 and Ia antigen was studied. Addition of exogenous recombinant IL-1 (rIL-1) stimulated the PFC response in control cultures, but had no effect on AM-mediated suppression. Resident AM could be activated with lipopolysaccharide or antigen to produce significant levels of IL-1. Membrane-bound IL-1, thought to be important in the presentation of particulate antigens, was detected on glutaraldehyde-fixed resident AM and was significantly elevated in BCG-activated macrophages. The frequency of cell surface Ia antigen expression was low in resident AM (4%), but could be increased (35%) after in vivo activation with BCG. Recombinant interferon-gamma (IFN-gamma), known to enhance expression of Ia antigen and production of IL-1, had no effect on AM-mediated suppression when used either to pretreat AM, when present during the entire period of culture, or when injected into mice before culture initiation. Treatment with IFN-gamma, however, resulted in a slight increase in the expression of Ia antigen. These results indicate that the immunosuppressive activity of AM is neither related to a defect in IL-1 production or expression nor to a deficiency in Ia antigen expression and therefore can not be explained by the inefficient antigen-presenting function of alveolar macrophages.

Animals↗
PubMed1987

Quantitative measurement of T-lymphocyte activation by an enzyme-linked immunosorbent assay (ELISA) detecting interleukin-2 receptor expression.

A monoclonal antibody prepared against the murine interleukin-2 receptor (IL-2R) was employed to develop an ELISA method for measuring the immunological activation of T-cells. The assay detects an increase in IL-2R expression on activated lymphocytes. Stimulated splenic lymphocytes displayed markedly higher IL-2R expression compared to unstimulated controls. A significant increase in IL-2R expression on lymphocytes was detected in mitogen-stimulated responses, in a one-way mixed leukocyte reaction (MLR) and in the antigen-specific responses to conalbumin and purified protein derivative (PPD) in vitro. At a constant cell number, the level of IL-2R expression was found to be dependent on the dose of the stimulant. A comparative study of the kinetics of activation of splenic lymphocytes in response to mitogen, antigen and allogeneic cells as measured by the IL-2R ELISA and the conventional tritiated thymidine (3HTdR) uptake assay revealed remarkable similarity. For both assays, the mitogenic response was detected within 12 h and peaked at 72 h, the MLR was detectable within 2-3 days and peaked at day 6, and the specific antigenic response was detected within 2 days and peaked on day 4-5. Hydroxyurea, an inhibitor of DNA synthesis, had no effect on early IL-2R expression by mitogen-stimulated splenic lymphocytes, however, only 20% of maximum IL-2R expression could be detected at later stages of incubation. In contrast, cycloheximide, an inhibitor of protein synthesis, completely abrogated IL-2R expression and proliferation of stimulated lymphocytes.

Animals↗
PubMed1986

Reversal of murine alveolar macrophage-mediated suppression of plaque-forming cell response by sodium periodate.

Murine alveolar macrophages (AM) have been shown to suppress the in vitro plaque-forming cell (PFC) response of spleen cells previously primed with sheep erythrocytes (SRBC) in a dose-dependent manner. Mild oxidation of cell membranes on viable AM with sodium periodate resulted in total abrogation of AM-mediated suppression of the PFC response, while periodate treatment of spleen cells resulted only in partial reduction of the suppression. Pretreatment of AM with sodium periodate followed by addition of the aldehyde blocking agent, hydroxylamine, resulted in restoration of the PFC-suppressing activity of AM. Periodate treatment of AM also resulted in significantly increased macrophage-T-cell binding and cluster formation. These observations suggest that the generation of aldehyde moieties on AM membrane sialoglycoconjugates promotes positive macrophage-lymphocyte interactions, resulting in abrogation of AM-mediated suppression of the PFC response.

Animals↗
PubMed1986

Enhanced recovery of murine alveolar macrophages: morphological and functional characteristics following intravenous injection of heat-killed Mycobacterium bovis BCG.

The kinetics of induction of the bronchoalveolar cell population (i.e., alveolar macrophages [AM], lymphocytes, and polymorphonuclear leukocytes) was studied in mice inoculated intravenously with heat-killed Mycobacterium bovis BCG. Injection of BCG at 100 and 500 micrograms but not at 10 micrograms per mouse resulted in an increase in the total number of bronchoalveolar cells (threefold) and in the number of AM (sixfold) recovered by bronchoalveolar lavage in a time-dependent manner, as compared with control mice. A significant increase in the number of lymphocytes was also observed between days 2 and 4 after injection, but this number returned to normal levels by day 8, whereas the number of polymorphonuclear leukocytes was not significantly altered. AM were characteristically phagocytic and stained positively for nonspecific esterase. AM recruited in response to BCG injection were activated, as indicated by elevated levels of acid phosphatase activity and decreased levels of membrane 5'-nucleotidase activity. However, both resident and BCG-induced AM suppressed the in vitro plaque-forming cell response of sheep erythrocyte-primed mice to the same extent. These results indicate that injection of heat-killed BCG induced increased numbers of activated AM, which appeared to be functionally similar to resident AM in their ability to phagocytize and modulate in vitro immune responses.

Acid Phosphatase↗
PubMed1984

Heterogeneity among alveolar macrophages in humoral and cell-mediated immune responses: separation of functional subpopulations by density gradient centrifugation on Percoll.

Rabbit alveolar macrophages (AM) were separated into four subpopulations by centrifugation on discontinuous density gradients of Percoll. The subpopulations were compared to unseparated AM populations for their ability to provide accessory function to adherent cell-depleted splenocytes for antigen-stimulated lymphoproliferation and for the production of lymphokine. They were also tested for their ability to modulate in vitro plaque-forming (PFC) responses. AM subpopulations that provided accessory function for the production of migration inhibitory factor (MIF)-containing culture supernatants were recovered from the least dense fractions of the Percoll gradients. These cells were cytochemically characterized as mature cells. AM that suppressed the in vitro PFC response and augmented the antigen-stimulated lymphoproliferative response to the greatest degree were recovered from the most dense fractions of the Percoll gradients and were characterized as immature cells. These results suggest that there are distinct subpopulations of AM, the function of which may represent different stages of maturation (or differentiation).

Animals↗
PubMed1984

Accessory cell function of human alveolar macrophages in B-cell activation induced by pokeweed mitogen.

The effect of alveolar macrophages (AM) on pokeweed mitogen (PWM)-stimulated immunoglobulin (Ig) secretion by unfractionated and monocyte-depleted human peripheral blood mononuclear cells was studied. Responsiveness in monocyte-depleted peripheral blood mononuclear cell populations could be partially restored by addition of autologous monocytes and to a lesser extent with AM. Addition of AM to unfractionated peripheral blood mononuclear cells resulted in significant inhibition of Ig secretion, especially at high (5-10 micrograms/ml) doses of PWM. The degree of suppression was proportional to the number of AM present. On the other hand, addition of monocytes to similar unfractionated peripheral blood mononuclear cell cultures did not result in suppression of Ig secretion at any of the doses of PWM used. Suppression by AM was not attributable to an alteration of response kinetics. The results demonstrate that mononuclear phagocytic cells are necessary for activation of polyclonal Ig secretion by human B cells and that AM are capable of suppressing this response.

B-Lymphocytes↗