bluuebunny/crossref_metadata_2025 huggingface dataset:
L3T4+ T cells regulate Abelson virus-induced lymphomagenesis.
Authors: Infante A J , Boulware S , Cagle M
Published: December 2022

To evaluate the role of T cells in regulation of lymphomagenesis, experiments were performed using Abelson murine leukemia virus (AMuLV). In vitro transformation of bone marrow target cells by this B lymphotropic retrovirus was inhibited by peripheral lymph node cells from naive mice. The inhibitory activity depended on Thy-1+ L3T4+ cells but did not require Lyt-2+ cells. In vivo depletion of L3T4+ T cells with a mAb (GK1.5) altered the course of AMuLV-induced lymphoma. L3T4 depletion of naturally resistant C57BL/6 mice resulted in dramatic susceptibility to lymphoma induction. Lymphoma cells from anti-L3T4-treated C57BL/6 mice infected with AMuLV displayed the B lineage transformation marker P1606C3. These studies reveal an important immunologic component of Abelson disease resistance involving L3T4+ T cells.
Lysis of a lung carcinoma by poly I:C-induced natural killer cells is independent of the expression of class I histocompatibility antigens.
Authors: Dennert G , Landon C , Lord E M , Bahler D W , Frelinger J G
Published: December 2022

Cells from the line 1 murine carcinoma express little if any H-2d when grown in normal medium. These cells are susceptible to splenic cell populations with NK activity, stimulated by prior injection of poly I:C, but are not lysed by NK-deficient splenocytes from homozygous beige mice treated with anti-asialo GM1. Incubation of line 1 cells in medium containing DMSO leads to a dramatic stimulation of H-2d expression but no change in lytic susceptibility to splenic NK cells. Transfection of H-2Dp into line 1 leads to a constitutive and DMSO-inducible expression of H-2Dp at functionally significant levels, but this expression appears to have no influence on NK cytolytic susceptibility.
Evidence for interactions between monocytes and natural killer cells in the regulation of in vitro hemopoiesis.
Authors: Kannourakis G , Begley C G , Johnson G R , Werkmeister J A , Burns G F
Published: December 2022

The role of accessory cells in modulation of in vitro hemopoiesis was studied using C-mediated lysis with mAb of differing specificities. One such antibody, 25E11, which bound to all NK cells and a subset of monocytes, consistently led to enhancement of in vitro hemopoiesis when 25E11+ cells were depleted by complement or the FACS. In cultures maximally stimulated by erythropoietin and human placental conditioned medium, depletion of 25E11+ cells from beta-thalassemic PBMC resulted in up to a fourfold enhancement of multi-potential and pure erythroid colonies and a twofold enhancement of non-erythroid colonies when compared with C-only treated cells. This enhancement of in vitro hemopoiesis was also observed with cells from normal bone marrow, cord blood, and peripheral blood. The enhancement of in vitro hemopoiesis was abrogated by removal of either adherent cells or monocytes using Leu M3 antibody and C lysis. The data presented herein suggest that NK cells and a subset of monocytes may exert a negative regulatory control on both granulopoiesis and erythropoiesis. Consequently, the number of progenitor and multipotential cells in cultures of unfractionated cell populations may be greatly underestimated.
Two roles for Ia in antigen-specific T cell activation. II. Toward a Velcro model of antigen recognition.
Authors: Kim K H , Thomas D W
Published: December 2022

It has been previously reported that Ia Ag on APC seems to be involved in Ag-specific T cell activation in at least two different ways: one is to associate with foreign Ag to form a neoantigenic determinant (the Ag-specific Ia function), and the second is to interact with T cells in a non-Ag-specific manner. Both Ia functions are required for T cell activation. In the present study we examined whether the T cell structures responsible for the non-Ag-specific Ia interaction were separable from the Ag-specific alpha/beta TCR. Purified protein derivative of tuberculin (PPD)-specific murine hybridoma T cells and polyclonal lymph node T cells were stimulated for IL-2 production by APC pulsed with PPD, glutaraldehyde fixed, and anti-Ia antibody treated, to provide the antigenic PPD/Ia determinant, in the presence of glutaraldehyde-fixed non-Ag-pulsed APC, to provide the non-Ag-specific Ia interactions. However, in several different approaches the T cell structures or activation signals responsible for the Ag-specific recognition and non-Ag-specific Ia interactions seemed to be associated with each other in this experimental system. First, the Ag-specific and non-Ag-specific Ia interactions with T cells were both required simultaneously to initiate T cell activation, and it was not possible to activate T cells by providing either Ia signal subsequent to the other. Second, the T cell structures responsible for the non-Ag-specific Ia interactions appeared to be clonally distributed in PPD-specific lymph node T cells. Third, another T cell hybridoma specific for bovine insulin also showed dual Ia interactions, but the specificity of the non-Ag-specific Ia function was different than that for the PPD-specific T cell response. Fourth, all subclones of PPD-specific T hybridomas that had lost Ag-specific responsiveness also lost functional non-Ag-specific Ia interactions. Taken together, these observations suggest that a single species of TCR may mediate both the Ag-specific and non-Ag-specific Ia interactions. In addition, the non-Ag-specific Ia interaction with T cells augmented the Ag-specific Ia interaction for T cell activation, indicating that both types of interactions may be involved in some T cell responses. Based on these observations, a Velcromodel depicting the synergy between the two Ia functions is proposed in which a matrix of interactions consisting of higher affinity Ag binding and lower affinity Ia-TCR associations provides cooperative sets of signals necessary for cellular activation.
T cell autoreactivity to insulin in diabetic and related non-diabetic individuals.
Authors: Naquet P , Ellis J , Tibensky D , Kenshole A , Singh B , Hodges R , Delovitch T L
Published: December 2022

T cell autoreactivity to insulin in type I diabetic and related non-diabetic individuals was analyzed. Peripheral T lymphocytes from both insulin-treated diabetic and untreated non-diabetic members of four families were found to proliferate in vitro in response to human insulin. T cell autoreactivity to insulin therefore does not appear to be diagnostic of the onset of type I diabetes. Highest T cell responses to human insulin were usually detected in insulin-dependent type I diabetes patients treated with a mixture of beef and pork insulin than with self insulin, the greater the dose of animal insulin the higher the T cell response. The T cell repertoires for self insulin appear to be similar in diabetics and non-diabetics based on their patterns of T cell reactivity to beef insulin, port insulin, human insulin, and various peptide of human insulin. The autoreactive T cells analyzed recognize two conformational epitopes of human insulin formed by interactions between A chain and B chain residues. One epitope is associated with the A chain loop and is present in the A1-A14/B1-B16 peptide, and the other epitope consists mainly of B chain residues located in the A16-A21/B10-B25 peptide. These two epitopes are present in amphipathic alpha-helical regions of insulin. HLA-DR (DR3, DR4, and DR5) and HLA-DQ (DQw2/DQw3) Ag can restrict these T cell responses to human insulin epitopes. The ability to detect insulin-specific autoreactive T cells in healthy non-diabetic individuals supports the hypothesis that autoreactive lymphocytes do not necessarily elicit autoimmune disease if present in an environment in which their activity is immunoregulated.
IL-2 receptor(p55)/Tac-inducing factor. Purification and characterization of adult T cell leukemia-derived factor.
Authors: Tagaya Y , Okada M , Sugie K , Kasahara T , Kondo N , Hamuro J , Matsushima K , Dinarello C A , Yodoi J
Published: December 2022

Many human T cell lymphotropic virus-I (HTLV-I) transformed T cells from adult T cell leukemia (ATL) patients continuously produce a humoral factor called ATL-derived factor (ADF) which induces IL-2R/Tac expression on T and NK cells. Using gel filtration, procion red Sepharose, DEAE, and reverse phase chromatography, we have purified ADF protein to homogeneity from 15 liters of serum-free culture supernatant of an HTLV-I(+) T cell line ATL-2. Purified ADF protein had the m.w. of 14,000 by SDS-PAGE and gel filtration, and its isoelectric point is around 5.0. ADF did not react with heteroantibodies against IL-1 alpha and IL-1 beta, which have also IL-2R/Tac-inducing activity on suitable target cells. Partial N-terminal amino acid sequence of ADF is different from other cytokines such as, IFN, BSF-2, and various IL whose cDNA has been cloned. Western blot analysis using rabbit antibodies against N-terminal 10mer synthetic peptide of ADF showed that IL-1 alpha and ADF are different proteins. ADF had its IL-2R/Tac-inducing activity not only on human NK-like cell line YT, but also on HTLV-I(+) T cells, such as ED. In contrast, macrophage-derived IL-1 lacked IL-2R/Tac-inducing activity on ED cells despite their IL-2R/Tac induction on YT, indicating that ADF and IL-1 have their effect via different receptors.
Simultaneous production of tumor necrosis factor-alpha and lymphotoxin by normal T cells after induction with IL-2 and anti-T3.
Authors: Steffen M , Ottmann O G , Moore M A
Published: December 2022

Normal human T cells purified from the peripheral blood and cultured for 6 days in the presence of OKT3 and IL-2 were shown to produce simultaneously TNF and lymphotoxin (LT) mRNA. Both biologically active TNF and LT were detected in supernatants of the cultured T cells using WEHI 164 as target cells. The cytotoxic activities of both cytokines could be inhibited with specific antibodies against TNF or LT. The T cell cultures were free of macrophages, NK cells, or B lymphocytes as assessed by flow cytometric analysis.
Comparative effects of tumor necrosis factor-alpha and IL-1 beta on mitogen-induced T cell activation.
Authors: Hackett R J , Davis L S , Lipsky P E
Published: December 2022

The effect of rTNF-alpha on human T cell function was examined and compared with that of rIL-1 beta by assessing the ability of each cytokine to support mitogen-induced proliferation, IL-2 production, and IL-2R expression. TNF-alpha and IL-1 beta each enhanced DNA synthesis induced by PHA or immobilized mAb to the CD3 molecular complex. In addition, each cytokine increased the number of cells entering the G1 phase of the cell cycle and augmented IL-2R expression. The combination of optimal concentrations of these factors supported these responses to a greater extent than either cytokine alone, suggesting that T cell responsiveness is independently regulated by the action of at least two separate monocyte derived cytokines. Whereas TNF-alpha had little effect, IL-1 beta augmented IL-2 mRNA expression and IL-2 production by mitogen-stimulated cells. Furthermore, IL-1 beta enhanced proliferation with increasing length of culture. Whereas TNF-alpha also enhanced proliferation late in culture, it was less effective in this regard than IL-1 beta. Thus, IL-1 beta and TNF-alpha augment mitogen-induced T cell proliferation by increasing the number of cells initially activated and by promoting subsequent cell cycle progression. They differ, however, in their capacity to promote IL-2 mRNA and IL-2 production and therefore ongoing T cell proliferation.
Analysis of Ia antigen expression in macrophages derived from bone marrow cells cultured in granulocyte-macrophage colony-stimulating factor or macrophage colony-stimulating factor.
Authors: Falk L A , Wahl L M , Vogel S N
Published: December 2022

Bone marrow cells from C3H/HeJ mice were cultured in recombinant granulocyte-macrophage-CSF (rGM-CSF) or recombinant or purified (natural) preparations of macrophage-CSF (CSF-1) for 7 days, the adherent macrophages removed enzymatically, recultured in the absence of growth factor, and examined for their differentiative and functional characteristics. Expression of Ia Ag differed markedly in these two populations. Antibody plus complement-mediated cytotoxicity indicated that the percent of Ia-positive macrophages was low (approximately 15 to 20%) in both populations. Treatment of cultures with rIFN-gamma increased the percentage of Ia-positive cells in both populations; however, more CSF-1-derived macrophages were induced to become Ia positive than rGM-CSF-derived macrophages. In contrast, total Ia expression and Ia density per cell, as measured by ELISA and quantitative immunofluorescence, respectively, showed that medium-treated rGM-CSF-derived macrophages exhibited greater total Ia expression and higher Ia density per cell than CSF-1-derived macrophages. Treatment of CSF-1-derived macrophages with rIFN-gamma increased total Ia expression per culture to the levels exhibited by rGM-CSF-derived cells, although the density of Ia Ag per cell remained lower than in rGM-CSF-derived cells (medium or rIFN-gamma-treated). Northern blot and slot blot analysis of cytoplasmic RNA extracted from freshly harvested rGM-CSF- or CSF-1-derived cells indicated that the differences seen in basal Ia expression were also reflected at the level of steady-state, Ia-specific mRNA. The functional capacity of these two macrophage populations to stimulate Ag-specific T cell proliferation was also assessed. rGM-CSF- or CSF-1-derived macrophages were first cultured in the absence or presence of rIFN-gamma, Ag-pulsed, and irradiated before co-culture with Ag-primed, purified T cells. Ag-induced T cell proliferation was significantly greater in rGM-CSF- than in CSF-1-derived macrophages. Treatment of either population with rIFN-gamma had only a minimal effect on the ability of either macrophage population to stimulate Ag-specific T cell proliferation. These findings suggest that the development of mature macrophages from bone marrow progenitors under the influence of either GM-CSF or CSF-1 may, in part, underlie the functional heterogeneity of different macrophage populations.
Differential proliferative effects of transforming growth factor-beta on human hematopoietic progenitor cells.
Authors: Ottmann O G , Pelus L M
Published: December 2022

Transforming growth factor-beta (TGF beta) regulates cell growth and differentiation in numerous cell systems, including several hematopoietic lineages. We used in vitro cultures of highly enriched hematopoietic progenitor cells stimulated by natural and recombinant growth factors to investigate the biologic effects of TGF beta 1 and TGF beta 2 on erythroid (CFU-E and burst-forming unit (BFU)-E), granulocyte-macrophage (CFU-GM) and multilineage (i.e., granulocyte, erythroid, macrophage, and megakaryocyte; CFU-GEMM) colony-forming cells. In the absence of exogenous CSF, neither TGF beta 1 nor TGF beta 2 supported progenitor cell growth. In the presence of recombinant or natural CSF, picomolar concentrations of TGF beta 1 inhibited growth of CFU-E, BFU-E, and CFU-GEMM and enhanced growth of day 7 CFU-GM. Inhibition of CFU-E and BFU-E by human and porcine TGF beta 1 was similar, ranging from 17 to 73% over a concentration range of 0.05 to 1.0 ng/ml, and was largely independent of the type of burst-promoting activity used (rIL-3 vs cell line 5637-conditioned medium). Inhibition of CFU-GEMM ranged from 79 to 98% over a concentration range of 0.25 to 1.0 ng/ml. The inhibitory effect of TGF beta 1 was progressively lost when its addition was delayed for 40 to 120 h, suggesting a mode of action during early cell divisions. In contrast, growth of CFU-GM stimulated by plateau concentrations of human rG-CSF, rGM-CSF, and rIL-3 was enhanced up to 154 +/- 22% by human TGF beta 1. Porcine platelet-derived TGF beta 2 was essentially without effect on the progenitor populations examined. These results support the hypothesis that TGF beta may play role in the regulation of hematopoietic progenitor cell proliferation by differentially affecting individual lineages and is apparently capable of doing so in the relative absence of marrow accessory cells.
The invariant tryptophan in an H chain V region is not essential to antibody binding.
Authors: Sharon J
Published: December 2022

The first amino acid residue of the second framework region in all antibody H and L chain V regions sequenced to date is invariably tryptophan. To test whether this invariance is essential to proper domain folding and generation of a functional antibody, the tryptophan residue in the heavy chain V region of a mouse anti-p-azophenylarsonate antibody was converted to an alanine residue by oligonucleotide-directed mutagenesis of the H chain gene. The mutant gene was transfected into mouse hybridoma cells that produce the homologous L chain, and the resulting mutant antibody was purified from the cell supernatant. It was shown to have essentially the same reactivity as wild type toward a series of anti-idiotypic antibodies and to bind Ag with a Ka similar to that of wild type.
Suppression of IL-2 production by cryopreserved peripheral blood mononuclear cells from patients with active visceral leishmaniasis in Sicily.
Authors: Cillari E , Liew F Y , Lo Campo P , Milano S , Mansueto S , Salerno A
Published: December 2022

The ability of PBMC from eight patients with confirmed visceral leishmaniasis (Leishmania donovani) to produce IL-2 in response to PHA in vitro was investigated. PBMC from the patients produced significantly lower levels of IL-2 and had reduced proliferative response to PHA at the time of disease diagnosis compared with healthy controls. Their ability to produce IL-1 in response to LPS was, however, unaltered. The patients also showed normal levels of OKT4+ and IL-2R+ cells in the peripheral blood, as judged by specific immunofluorescence staining. All patients were given antimony therapy, and five were cured. The recovered patients showed significant improvement in the IL-2 producing capacity of their PBMC. The PBMC preparations of patients and controls were cryopreserved before and after successful chemotherapy on the patients. The frozen cell preparations were thawed and viable autologous cells cocultured with equal numbers of PBMC from patients before and after chemotherapy. The frozen cells from five healthy controls showed little or no difference whether they were cultured together or separately. In contrast, coculturing of cells from the five recovered patients with autologous pretreatment cells produced significantly and consistently lower levels of IL-2 compared with those produced when the cells were cultured separately. These results therefore demonstrate that the PBMC from patients with visceral leishmaniasis contain a population of cells that are capable of suppressing the IL-2 production by autologous PBMC from recovered patients. The method of cryopreservation should be useful for studying the immune regulation in this and other clinical diseases in vitro.
Human resistance to Schistosoma mansoni is associated with IgG reactivity to a 37-kDa larval surface antigen.
Authors: Dessein A J , Begley M , Demeure C , Caillol D , Fueri J , dos Reis M G , Andrade Z A , Prata A , Bina J C
Published: December 2022

The aim of this work was to determine whether human resistance to Schistosoma mansoni was associated with increased antibody reactivity to certain larval surface Ag. To this end, young residents of a hyperendemic area were selected for their low or high susceptibility to reinfection after parasitologic cure, and the reactivity of their sera to individual larval surface Ag was determined at different times before and after treatment. The data showed that six Ag: 202, 165, 90 to 92, 85, 72, and 37 kDa are the principal targets on the larva of IgG in the sera of resistant subjects. The comparative study, by immunoblotting and ELISA on purified Ag, of the sera from high and low susceptibility subjects indicates that IgG reactivity toward the 37-kDa Ag may be associated with resistance. This work and ongoing vaccination trials carried out in mice suggest that the 37-kDa Ag may have vaccinating potentials.
T cells recognizing polysaccharide-specific B cells function as contrasuppressor cells in the generation of T cell immunity to Pseudomonas aeruginosa.
Authors: Powderly W G , Schreiber J R , Pier G B , Markham R B
Published: December 2022

The cellular interactions involved in the development of T cell-mediated immunity to Pseudomonas aeruginosa have been examined. T cell immunity can be generated by immunizing mice with 10 micrograms of P. aeruginosa polysaccharide (PS) plus the antimitotic agent vinblastine sulfate. Vinblastine is required to inactivate a population of Ts cells generated by immunization with 10 micrograms of PS alone. Immunization with either live bacteria or with higher dose (50 micrograms) of PS without vinblastine also generates T cell immunity; these protocols activate a population of Lyt-1+, 2-, I-J+ T cells which, like vinblastine, counteract the effect of Ts cells. Immunization with 10 micrograms PS alone fails to activate this T cell subpopulation. When administered at the time of immunization, this subpopulation can render the tolerogenic 10-micrograms immunization protocols immunogenic. Like previously described contrasuppressor T cells, this T cell subpopulation exhibits an affinity for the lectin Vicia villosa. We have determined, however, that the T cells that act as contrasuppressor cells in this system are directly activated by PS-immune B cells and not by PS Ag. Furthermore, their activity can be removed by adsorption to PS-specific B cell hybridomas. Our studies indicate an important role for B cells in the development of T cell immunity to P. aeruginosa and suggest that a complex idiotype network controls the development of this response.
Isolation and expression of an IFN-responsive Ly-6C chromosomal gene.
Authors: Bothwell A , Pace P E , LeClair K P
Published: December 2022

The Ly-6 locus controls the expression of genes whose products in lymphoid cells are involved in the process of Ag-independent T cell activation. The Ly-6 locus contains multiple tightly linked genes which have been mapped to a specific region on murine chromosome 15. The present approach to further define the Ly-6 Ag is based on the transfection of cloned genes and identification of the expressed products by using mAb. Screening of Ly-6 related chromosomal clones revealed one that contains a gene that is closely related to yet distinct from that of the previously characterized Ly-6E.1 protein. Transfection of this chromosomal clone into COS cells shows that it contains the gene encoding Ly-6C.1 determinants. The expression of the transfected Ly-6C.1 gene is enhanced in COS cells following treatment with mouse IFN. Characterization of the DNA sequence of the Ly-6C.1 gene has established that it consists of four exons, the first of which is untranslated. Several possible regulatory elements have been identified in the putative promoter region of this gene (5' to the first exon), including a 28-base sequence closely resembling the consensus IFN-responsive sequence found in the promoter regions of other IFN-responsive genes.
Lymphokine-activated killer cells in rats. IV. Developmental relationships among large agranular lymphocytes, large granular lymphocytes, and lymphokine-activated killer cells.
Authors: Maghazachi A A , Vujanovic N L , Herberman R B , Hiserodt J C
Published: December 2022

The developmental relationships among large agranular lymphocytes (LAL) large granular lymphocytes (LGL) and the activation of these cells into lymphokine-activated killer (LAK) cells by rIL-2 was investigated. Highly enriched populations of LAL were isolated from Fischer 344 spleen cells by a combination of nylon-wool filtration (to remove B cells and macrophages), treatment with a pan T cell antibody plus complement (to remove T cells) and incubation in L-leucine methyl ester (to remove LGL). The resultant cells were highly enriched in morphologically identifiable LAL which expressed asialo GM1 and partially expressed the OX8 surface marker. The enriched LAL did not contain detectable NK cytotoxic activity, did not express pan T cell (OX19), Ia, Ig, or laminin surface markers and contained less than 0.2% LGL. Incubation of LAL in a low dose of rIL-2 (100 U/ml) induced the generation of LGL having NK activity within 24 h of culture. Longer culture periods (48 h) resulted in a continued increase in the percentage of LGL and higher levels of NK activity. However, with this low dose of rIL-2, little or no LAK activity (i.e., reactivity against NK-resistant target cells) was generated. With a high dose of rIL-2 (500 U/ml), LAL responded by first generating LGL with NK activity (within 24 h), with subsequent generation of LAK activity by 48 h. Evidence that the development of granular lymphocytes from LAL was responsible first for NK activity and then LAK activity was demonstrated by depletion of the generated granular NK or LAK effector cells by second treatments with L-leucine methyl ester. Concomitant with the induction of LGL with NK or LAK activity, rIL-2 also caused LGL to proliferate and expand four- to five-fold in 48 h. This occurred in the presence of high or low dose rIL-2. These results indicate that LAL are the precursors of LGL/NK cells, that LAL, LGL/NK cells and LAK cells appear to represent sequential developmental or activation stages and that LAL may comprise major source of LAK progenitors in lymphoid populations having few LGL or mature active NK cells.
Peritoneal B cells respond to phorbol esters in the absence of co-mitogen.
Authors: Rothstein T L , Kolber D L
Published: December 2022

B cells obtained by irrigation of the peritoneal cavity differ from splenic B cells in signaling requirements for the initiation of DNA synthesis. Splenic B cells are stimulated to enter S phase by phorbol esters in conjunction with a second signal provided by calcium ionophore; however, splenic B cells are not stimulated by phorbol ester alone. In contrast, peritoneal B cells from NZB and BALB/c mice were stimulated to incorporate tritiated thymidine by each of the phorbol esters, PMA and phorbol dibutyrate, acting alone. Stimulation of peritoneal B cells was apparent when cells were cultured at lower than usual cell densities, and responses were unaffected by coculture with splenic B cells. Responding cells adhered to plastic petri dishes coated with anti-mouse IgM antibody, but were not completely removed by treatment with anti-Ly-1.2 antibody plus C. These results indicate that phorbol esters constitute a complete signal that stimulates some peritoneal B cells to enter S phase.
IL-2 receptor inducibility is blocked in cortical-type thymocytes.
Authors: Boyer P D , Rothenberg E V
Published: December 2022

Activation of mature T cells induces the expression of high affinity receptors for the T cell growth hormone, IL-2. A short term assay was used to determine the capacity of murine thymocyte subpopulations to express the gene encoding the 55-kDa chain of the IL-2R after stimulation in vitro. Thymocytes were cultured in the presence or absence of phorbol ester and calcium ionophore for 20 h, stained with antibodies against the IL-2R or the MHC Ag, H-2K, and analyzed by FACS. At least 90% of CD4-CD8- thymocytes were competent to express IL-2R, implying that this functional response is acquired early in development. However, at least 80% of cortical thymocytes were unable to express IL-2R before or after stimulation. Additional fractionation of the nonresponsive cells indicated that they constitute the great majority of the CD4+CD8+ population, including virtually all of the CD4+CD8+ proliferating blasts. Most nonresponsive cells remain viable and react to the chemical stimuli by increasing their surface expression of H-2K. The inability of most cortical thymocytes to express IL-2R suggests that a discrete loss of function occurs in most cells as they differentiate from CD4-CD8- precursors into the CD4+CD8+ class. The inferred loss of function is mediated at the level of IL-2 RNA accumulation and may be correlated with a pleiotropic alteration in physiologic response pathways.
Hormone receptors on cloned T lymphocytes. Increased responsiveness to histamine, prostaglandins, and beta-adrenergic agents as a late stage event in T cell activation.
Authors: Dailey M O , Schreurs J , Schulman H
Published: December 2022

Lymphocytes have surface receptors for a variety of hormones that play an important part in modulating the immune response. Most previous studies, however, have examined the effects of hormone agonists on heterogeneous bulk populations of cells, making it difficult to precisely identify the responding target cells. We have therefore studied a set of well characterized T cell clones for a series of adenylate cyclase-linked hormone receptors and examined changes in receptor expression that occur after cell activation. All clones tested had receptors for histamine, isoproterenol, and PGE1, but not for several other cAMP-active hormone agonists. The apparent receptor affinities and their specificities were characteristic of typical histamine H2, beta 2-adrenergic, and PGE receptors. The cAMP response to PG was higher and longer lasting than that to histamine or isoproterenol, both of which appear to undergo receptor desensitization. After activation of quiescent cells in IL-2-containing media, the cAMP response to all three ligands increased, peaking 4 to 5 days after stimulation, and then returned to basal levels as the cells ceased proliferating. Inasmuch as this effect did not require Ag, it appears that the coordinate regulation of responsiveness to these ligands is a direct result of lymphocyte activation. This increase in hormone receptor activity is functionally analogous to the up-regulation of receptors for other ligands that occurs after lymphocyte activation and further demonstrates the important immunoregulatory role played by the changing repertoire of surface receptors that is associated with activation.
The production and characterization of murine monoclonal antibodies to a DNA receptor on human leukocytes.
Authors: Bennet R M , Hefeneider S H , Bakke A , Merritt M , Smith C A , Mourich D , Heinrich M C
Published: December 2022

Two murine mAb have been generated with a reactivity toward a 30,000 m.w. DNA binding protein found on the cell surface of human leukocytes; mAb 12A has an IgG1/k isotype, and mAb 24T has an IgG2b/k isotype. Both react with the DNA binding domain or adjacent region of the putative DNA receptor and inhibit the binding of [3H]DNA to PBMC at concentrations as low as 100 ng/ml. Stoichiometric studies indicate that both mAb react with monocytes and T cells with a kDa of 10(-7) M; about 0.5 x 10(6) molecules bind per cell at saturation. Flow cytometry indicated that 67% of lymphocytes and 98% of monocytes bore the DNA receptor. Dual labeling studies showed that 90% of B cells and 50% of T cells express the receptor; 50% of CD4+ T cells are receptor positive. Immunomatrices constructed with both mAb 12A and 24T allowed the receptor to be purified to a high degree of purity. A single protein of Mr 30,000 was readily observed after SDS-PAGE and silver staining of the gel; after electropheretic transfer of nitrocellulose this protein was shown to be a DNA binding molecule by use of a probe of biotin labeled DNA. These experiments provide further evidence to support the existence of a specific DNA receptor on human leukocytes; the availability of mAb to the receptor should be useful in its further characterization.
Lymphocyte recruitment in delayed-type hypersensitivity. The role of IFN-gamma.
Authors: Issekutz T B , Stoltz J M , vd Meide P
Published: December 2022

Lymphocytes are recruited out of the blood into delayed-type hypersensitivity (DTH) reactions, but the factors controlling their migration are poorly understood. Our previous studies have shown that IFN-alpha/beta, its inducers, and T cell lymphokines can induce lymphocyte migration into the skin after intradermal injection. The present studies were designed to determine the effect of rIFN-gamma, IL-1, and anti-IFN-gamma on lymphocyte recruitment into DTH. Small peritoneal exudate lymphocytes, which preferentially migrate to inflammatory sites, were labelled with 111In and injected i.v. into rats. The intradermal injection of IFN-gamma stimulated the migration of these lymphocytes into the skin. IL-1 induced very little migration by itself, but enhanced the effect of IFN-gamma. Kinetic analysis demonstrated that the migration of lymphocytes to IFN-gamma was rapid, with a peak at 6 h, whereas migration into a DTH reaction was minimal for the first 8 h and reached a peak 24 h after intradermal injection. Polyclonal rabbit anti-IFN-gamma anti-serum, and a Mab to IFN-gamma, DB-2, could almost completely block lymphocyte migration induced by IFN-gamma. Furthermore, DB-2 inhibited lymphocyte recruitment into DTH reactions by 50 to 90%. This Mab did not affect migration in response to IFN-alpha/beta, although it partially inhibited the response to polyI:C. The effect of IFN-gamma on lymphocyte recruitment was not specific for small peritoneal exudate lymphocytes, because both spleen T cells and lymph node cells migrated in response to IFN-gamma and DB-2 inhibited the recruitment of splenic T cells to DTH. Thus, IFN-gamma is a potent stimulator of lymphocyte migration into the skin and a major mediator of lymphocyte recruitment into DTH.
Tumor necrosis factor-induced changes of gene expression in U937 cells. Differentiation-dependent plasticity of the responsive state.
Authors: Schütze S , Scheurich P , Schlüter C , Ucer U , Pfizenmaier K , Krönke M
Published: December 2022

TNF-alpha alone or in combination with IFN-gamma differentially affects the proliferation and differentiation of the human leukemic cell line U937 and two derivatives C27 and G3. All three cell lines express similar numbers of functional, high affinity receptors for both TNF-alpha and IFN-gamma. In C27 and G3 cells, TNF-alpha as well as IFN-gamma induced changes in steady state levels of specific mRNA, which appear to be associated with TNF-alpha and IFN-gamma diverse effects on cell growth and differentiation. Constitutive differences in membrane phosphorylation patterns suggest that altered transduction of TNF-alpha signals may account for the differential response of these three cell lines. Several lines of evidence indicate that C27 and G3 cells, when compared with parental U937 cells represent discretely higher stages of monocytic differentiation, suggesting that cellular differentiation may contribute to the development of resistance to the action of TNF-alpha.
Recombinant granulocyte-macrophage colony-stimulating factor down-regulates expression of IL-2 receptor on human mononuclear phagocytes by induction of prostaglandin E.
Authors: Hancock W W , Pleau M E , Kobzik L
Published: December 2022

Recent studies have shown that normal human alveolar macrophages and blood monocytes, as well as HL-60 and U937 monocyte cell lines, newly express IL-2R after stimulation with rIFN-gamma or LPS. In addition, macrophages transiently express IL-2R in vivo during immunologically mediated diseases such as pulmonary sarcoidosis and allograft rejection. We therefore investigated in vitro factors that modulate macrophage expression of IL-2R. IL-2R were induced on normal alveolar macrophages, blood monocytes, and HL-60 cells using rIFN-gamma (24 to 48 h at 240 U/ml), and cells were cultured for an additional 12 to 24 h with rIL-2 (100 U/ml), recombinant granulocyte-macrophage CSF (rGM-CSF, 1000 U/ml), rGM-CSF plus indomethacin (2 X 10(-6) M), PGE2 (0.1 to 10 ng/ml), 1 X 10(-6) M levels of caffeine, theophylline, and dibutyryl cyclic AMP, or medium alone. IL-2R expression was quantitated by cell ELISA (HL-60 cells) or determined by immunoperoxidase staining (alveolar macrophages, blood monocytes, and HL-60 cells), using anti-Tac and other CD25 mAb. PGE production was assayed by RIA. We found greater than 95% of alveolar macrophages, monocytes, and HL-60 cells expressed IL-2R after rIFN-gamma treatment and remained IL-2R+ in the presence of IL-2R or medium alone. By comparison, greater than 95% of cells induced to express IL-2R became IL-2R- after addition of rGM-CSF, and the culture supernatants from GM-CSF-treated cells contained increased levels of PGE. This inhibition of macrophage IL-2R expression by rGM-CSF was blocked by indomethacin, and IL-2R+ macrophages became IL-2R- after addition of PGE2 alone. These findings indicate GM-CSF down-regulates IL-2R expression by human macrophages via induction of PGE synthesis. Moreover, a similar down-regulation of IL-2R expression was seen after stimulation with caffeine, theophylline, or dibutyryl cyclic AMP. Hence, GM-CSF, PGE, and other pharmacologic agents that act to increase intracellular levels of cAMP may play a modulatory role, antagonistic to that of IFN-gamma on cellular expression of IL-2R by human inflammatory macrophages in vivo.
Topologic analysis of the epitopes of a variant surface glycoprotein of Trypanosoma brucei.
Authors: Masterson W J , Taylor D , Turner M J
Published: December 2022

A panel of variant-specific mAb has been raised against the Trypanosoma brucei variant MITat 1.2. The binding characteristics of these mAb have been determined by a combination of immunofluorescence assays, using living or fixed trypanosomes, and solid phase assays, using purified variant surface glycoprotein. In addition, these mAb have been tested for their ability to neutralize MITat 1.2 infections in mice. Finally, the epitopes recognized by the mAb have been defined by competitive binding assays. These results are discussed with respect to the structural organization of the surface coat of T. brucei.
Human antibodies to group A streptococcal carbohydrate. Ontogeny, subclass restriction, and clonal diversity.
Authors: Shackelford P G , Nelson S J , Palma A T , Nahm M H
Published: December 2022

To investigate immuno-incompetence to polysaccharide Ag in young children, antibodies to the polysaccharide and protein Ag of Streptococcus pyogenes were studied. S. pyogenes was chosen because it commonly causes natural infections and has well-characterized polysaccharide and protein Ag. In children over the age of 2 yr it was found that the maturation of antibody responses to the polysaccharide Ag of S. pyogenes (A-CHO) appeared to occur in parallel with, or even earlier, than the responses to streptococcal protein Ag. When antibodies to group A carbohydrate (A-CHO) were studied in detail, qualitative differences between the antibodies of children and adults were demonstrated. Although anti-A-CHO antibodies of adults were strikingly restricted to the IgG2 subclass, those of children were found in both the IgG1 and IgG2 subclasses. In addition, the clonal diversity of IgG antibodies to A-CHO increased with age, and additional clonotypes were detectable in convalescent sera of some subjects of all ages after infection. Two cases with major additional clonotypes after group A streptococcal infection were studied in detail. In these two cases the additional clonotypes belonged to a different IgG subclass than the previously dominant clonotypes, and the expression of the additional major clonotypes occurred in both IgG1 and IgG2 subclasses.
Rearrangement of IgH genes in normal thymocyte development.
Authors: Born W , White J , Kappler J , Marrack P
Published: December 2022

IgH chain gene segments are rearranged in 30 to 50% of peripheral T cells. We have analyzed IgH gene rearrangements during normal T cell development, using a well characterized collection of hybridomas derived from fetal, newborn, adult, or aged thymocytes. Our results show that IgH rearrangements occur in the thymus after T cell receptor gene and T cell specific gamma-gene rearrangements but before thymocyte maturation is completed. Therefore IgH gene rearrangements occur at an intermediate stage in thymocyte development. This may be of significance in delineating human lymphoid leukemias. Not all thymocyte hybridomas carried IgH gene rearrangements. Age-related shifts in frequencies of cells with IgH gene rearrangements, probably indicating changes in the composition of thymocyte populations, were found. Finally, a detailed analysis of D to J joins revealed an ordered progression of partial rearrangements at the IgH locus, whereby the most proximal DH-segment, DQ52, is used predominantly at early stages, but that other D to J rearrangements at the same locus may occur subsequently.
Escape mechanisms of melanoma from immune system by soluble melanoma antigen.
Authors: Takahashi K , Ono K , Hirabayashi Y , Taniguchi M
Published: December 2022

We demonstrate in the B16 melanoma (C57BL/6 derived) system that the soluble form of tumor Ag preferentially suppresses immune responses 1) by inhibiting CTL activity in the effector phase and 2) by induction of specific Ts that block CTL generation in the induction phase. Soluble melanoma antigen Ag injected i.p. into the tumor-bearing host can effectively augment melanoma growth in vivo. Two T cell types with the L3T4+ or double-negative/I-J+ phenotype are involved in the suppression of anti-melanoma CTL responses and can easily be generated in the in vitro primary 12 h-culture. Anti-melanoma Ts recognizes the GM3(NeuAc) structure and distinguishes GM3 molecular species. This is because liposomes constructed with GM3(NeuAc) but not with GM3(NeuGc) gangliosides alone can effectively induce the melanoma-specific Ts. It is thus likely that tumor cells can escape from the immunologic surveillance system by stimulating the repertoire of Ts for self-Ag, GM3, which has existed even in the unprimed conditions in order to maintain self-tolerance. These would appear to be the major escape mechanisms.
Activation of murine natural killer cells and macrophages by 8-bromoguanosine.
Authors: Koo G C , Jewell M E , Manyak C L , Sigal N H , Wicker L S
Published: December 2022

It has been shown that 8-bromoguanosine (8-BrGuo) activates T and B cells, but the underlying mechanism of this effect is not clear. We found that it also activates NK cells and macrophages by induction of IFN production. Culturing spleen cells with 8-BrGuo for 16 to 18 h induced cytotoxic activity to YAC cells. The cytotoxic cells expressed Qa-5, asialo-Gm-1, and NK-1.1 Ag. Similarly, preincubation of peptone-elicited peritoneal macrophages with 8-BrGuo induced macrophage cytolytic activity to P815 cells in an 18-h assay. Anti-IFN antibodies to IFN-alpha -beta and -gamma abolished these inductive events. Furthermore, elimination of asialo-Gm-1+ cells reduced the responses of NK and macrophages to 8-BrGuo, indicating that these cells possibly produce the IFN. We conclude from these observations that one biologic effect of 8-BrGuo is due to IFN production.
Flavone-8-acetic acid augments systemic natural killer cell activity and synergizes with IL-2 for treatment of murine renal cancer.
Authors: Wiltrout R H , Boyd M R , Back T C , Salup R R , Arthur J A , Hornung R L
Published: December 2022

The investigational drug flavone-8-acetic acid (FAA) potently augments NK activity in the spleen, liver, lungs, and peritoneum in a dose-dependent manner after i.v. or i.p. administration. Augmented NK activity peaks by 24 h after FAA injection and returns to normal after 6 days. Combined treatment of established murine renal cancer with FAA and rIL-2 results in up to 80% long term survival whereas FAA or rIL-2 alone were unable to induce any long term survivors. The optimal dose of rIL-2 required for use with FAA was in the range of 10,000 to 30,000 U/day. Further studies demonstrated that the regimen of FAA plus rIL-2 administration that was effective in treating established murine renal cancer also induced a more potent augmentation of NK activity than did either FAA or rIL-2 alone. Subsequent studies revealed that the therapeutic effectiveness of FAA plus rIL-2 was significantly reduced when tumor-bearing mice were treated with anti-asialo GM1 serum. These results are consistent with a role for augmented NK activity in the therapeutic effects of FAA plus rIL-2 murine renal cancer. In addition, these studies demonstrate that FAA and rIL-2 is a useful approach for cancer treatment in that subtoxic doses of rIL-2 can be used and significant anti-tumor efficacy occurs even without accompanying adoptive immunotherapy.
The expression and functional involvement of laminin-like molecules in non-MHC restricted cytotoxicity by human Leu-19+/CD3- natural killer lymphocytes.
Authors: Schwarz R E , Hiserodt J C
Published: December 2022

We have recently reported a simple technique for the purification of large granular lymphocyte/NK cells with broad anti-tumor cytotoxicity (lymphokine-activated killer (LAK) activity) by the induction of their adherence to plastic surfaces by recombinant IL-2. Using this technique with nylon wool passed human peripheral blood or splenic lymphocytes we generated populations of adherent LAK (A-LAK) cells which were 80 to 95% large granular lymphocyte and up to 97% Leu-19+ cells. Using two-color fluorescence and cell sorting we now demonstrate that these same cells express a high density of surface structures which are immunochemically cross-reactive with affinity purified anti-laminin antibody. Laminin-like structures were expressed on 80 to 90% of Leu-19+/CD3- LAK cells but were not expressed on resting CD3+/CD4+/Leu19- T cells or CD3+/CD8+/Leu19- T cells. Laminin-like molecules were also expressed on resting Leu19+/CD3- large granular lymphocyte/NK cells (purified to more than 98% by cell sorting) and increased in intensity as these cells developed LAK activity in response to rIL-2. The functional involvement of laminin-like molecules in NK and LAK cytotoxicity was demonstrated by the ability of affinity purified anti-laminin F(ab')2 antibody to inhibit cytolytic activity in a dose-dependent manner (50% inhibition with 10 to 20 micrograms F(ab')2). Analysis of the mechanism of inhibition using single cell cytotoxicity assays indicated that the laminin-like structure was involved in activation of cytotoxicity and not in primary target cell adhesion. We believe that this structure may function as a novel recognition/activation structure used by cells mediating non-MHC restricted cytotoxicity.
The effect of human recombinant macrophage colony-stimulating factor (CSF-1) on the murine mononuclear phagocyte system in vivo.
Authors: Hume D A , Pavli P , Donahue R E , Fidler I J
Published: December 2022

Human recombinant macrophage CSF (CSF-1) was administered i.v. to mice. After four daily injections there was a dose-dependent increase in the responsiveness of bone marrow cells from the treated animals to CSF-1 in vitro. At the highest dose tested (20,000 U/day) there was a selective 10-fold increase in the circulating population of mature monocytes. CSF-1 treatment also increased the macrophage content of the liver and peritoneal cavity and caused splenomegaly. The macrophages isolated from the peritoneum of CSF-1-treated animals were larger and expressed higher levels of the macrophage-specific F4/80 Ag. These data demonstrate that CSF-1 can act as a circulating regulator of the mononuclear phagocyte system.