bluuebunny/crossref_metadata_2025_split huggingface dataset:
Human lymphokine-activated killer (LAK) cells: identification of two types of effector cells.
Authors: Tilden A B , Itoh K , Balch C M 
Published: December 2022

Abstract
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+).
Inhibition of human B cell responsiveness by prostaglandin E2.
Authors: Simkin N J , Jelinek D F , Lipsky P E 
Published: December 2022

Abstract
The capacity of prostaglandin E2 (PCE2) to modulate human peripheral blood B cell proliferation and the generation of immunoglobulin-secreting cells (ISC) stimulated by Cowan 1 strain Staphylococcus aureus and mitogen-stimulated T cell supernatant was examined. PGE2 significantly inhibited both responses, whereas PGF2 alpha had no inhibitory effect. Responses of highly purified B cells obtained from spleen, lymph node, and tonsil were also inhibited. In addition PGE2 suppressed B cell responses supported by recombinant interleukin 2 rather than T cell supernatant. PGE2-mediated inhibition was mimicked by forskolin, a direct activator of adenylate cyclase. Kinetic studies indicated that PGE2 inhibited B cell responses by a progressively greater increment as cultures were prolonged. Evaluation by flow cytometry after staining with acridine orange or mithramycin indicated that PGE2 had no effect on initial B cell entry into the G1 phase of the cell cycle, passage through G1, and entry into S, G2, and M. Rather, PGE2 inhibited responses of postdivisional daughter cells. PGE2 inhibited responses in cultures stimulated by the calcium ionophore ionomycin and T cell supernatant but had minimal effects in cultures stimulated by the combination of ionomycin and phorbol myristate acetate. Moreover, phorbol myristate acetate reversed PGE2-mediated inhibition of proliferation stimulated by S. aureus or S. aureus + T cell supernatant. These results indicate that PGE2 suppresses the continued growth and differentiation of human B cells, although it has no effect on initial B cell activation and suggest that PGE2 may play a role in regulating human B cell responses in vivo.
Characterization of a novel murine T cell-activating factor.
Authors: Garman R D , Raulet D H 
Published: December 2022

Abstract
Purified resting peripheral lymph node T cells can be activated to produce interleukin 2 (IL 2) and to proliferate in the presence of Concanavalin A (Con A) and an apparently novel lymphokine that we call T cell activating factor (TAF). TAF is biochemically distinct from IL 1, IL 2, IL 3, and other colony stimulating factors, IL 4 (BSF-1) and interferons. Furthermore, of the recombinant and natural cytokines tested, only IL 2 and TAF are active in the TAF assay. In the presence of Con A, TAF stimulates an increase in the steady-state level of IL 2 mRNA in T cells, the secretion of active IL 2 into the culture medium, and the proliferation of the T cells. We propose that TAF is a previously undescribed molecule the function of which is to stimulate IL 2 production by T cells that have encountered antigen, and we propose that TAF has an important role in primary T cell immune responses.
A quantitative analysis of antigen-triggered lymphokine production by activated T cells.
Authors: Gill R G , Babcock S K , Lafferty K J 
Published: December 2022

Abstract
We have developed a theoretical model to describe the triggering of lymphokine release from antigen-specific, activated T (T') cells, and we have used this model to define parameters that regulate this interaction. Under assay conditions of T' cell excess, the efficiency of triggering is a function of the target cell type. When various H-2k-bearing target cells were used to trigger B10.AQR T' cells activated against B10.A cells (anti-Kk), a hierarchy of triggering efficiency was observed with B10.A Con A blasts greater than R1.1 tumor cells greater than B10.A spleen cells greater than B10.A lymph node cells. There was a 10-fold difference in triggering efficiency between Con A blasts and lymph node cells. A similar pattern of reactivity was observed for various H-2d-bearing target cells used to trigger CBA T' cells specific for BALB/c antigens (anti-H-2d). Under assay conditions of T' cell excess, the order of reaction, i.e., the number of target cells per T' cell required to trigger lymphokine release, remained constant for the different target cell types. However, the order of reaction can vary with conditions of T cell activation. CBA T' cells activated against BALB/c spleen cells exhibited pseudo-first-order reactivity when triggered for lymphokine release with P815 target cells, whereas CBA T' cells activated against UV-irradiated P815 cells exhibited pseudo-second-order reactivity when triggered by the same tumor cells. Thus, T cells with the same apparent specificity can be qualitatively different in their reactivity with antigen. Under assay conditions of target cell excess, our analysis indicated that no T-T interaction was involved in the triggering reaction. Finally, our analysis was applied to study the nature of cross-reactivity. The results indicated that the triggering of lymphokine elicited by a cross-reactive antigen was due to the reactivity of a discrete subset of T' cells.
Use of a DNA probe to measure the neutralization of Plasmodium berghei sporozoites by a monoclonal antibody.
Authors: Ferreira A , Morimoto T , Altszuler R , Nussenzweig V 
Published: December 2022

Abstract
A specific DNA probe has been used to quantify the neutralizing effects of monoclonal antibodies (3D11) against the circumsporozoite protein of Plasmodium berghei sporozoites. The amount of parasite DNA was measured in the livers of Norway Brown rats at the peak of proliferation of the exoerythrocytic forms (EEF). In vitro treatment of 1.5 X 10(5) sporozoites with 0.36 microgram/0.5 ml of whole 3D11 IgG neutralized about 90% of the sporozoite infectivity. When the dose was 3.6 micrograms no signal was detected, indicating that less than ten sporozoites developed into EEF in the liver. In contrast, 3.6 micrograms of Fab obtained from 3D11 neutralized sporozoite infectivity by only 60%. Although the neutralizing effect of 3D11 was very marked, the infected rats developed parasitemias after a prolonged delay in patency, suggesting that a small proportion of sporozoites was resistant to the effects of 3D11. The sporozoites were subjected to four cycles of 3D11-mediated selection, each one involving treatment of sporozoites with the antibodies, injection of the mixture into rats, infection of hamsters with blood stage parasites obtained from the rats, feeding of Anopheles stephensi on these hamsters, and obtaining sporozoites from the salivary glands of the infected mosquitoes. After four cycles of selection, the susceptibility of the resulting sporozoites to different concentrations of 3D11 was compared with that of nonselected sporozoites. No differences were detected, indicating that the capacity of a few sporozoites to escape the neutralizing effect of 3D11 antibodies is not inherited.
Identification of an interferon-gamma response region 5' of the human histocompatibility leukocyte antigen DR alpha chain gene which is active in human glioblastoma multiforme lines.
Authors: Basta P V , Sherman P A , Ting J P 
Published: December 2022

Abstract
The expression of class II major histocompatibility (MHC) antigens is central to the mounting of a successful immune response. Understanding the molecular mechanisms involved in the induction of class II MHC expression may therefore provide the knowledge necessary to manipulate the immune system appropriately. We are particularly interested in the induction of class II MHC antigens on cells in the brain, because of the potential involvement of such brain cells in the initiation and perpetuation of autoimmune-like diseases of the central nervous system. We examined the mechanisms involved in interferon-gamma (IFN-gamma) induction of class II MHC antigens on a human glioblastoma multiforme cell line. This paper describes the identification of a 297-bp (base pair) fragment of the class II MHC DR alpha chain gene which is involved in IFN-gamma induction. We were able to identify this IFN-gamma responsive sequence by preparing recombinant plasmids containing 5' flanking pieces of the human DR alpha chain gene placed upstream of the indicator gene, chloramphenicol acetyltransferase (CAT). These recombinant plasmids were transfected into human glioma cells which were then cultured in the presence or absence of IFN-gamma. After 48 hr, transient expression of CAT was assayed by thin layer chromatography. CAT enzyme activity was significantly increased only in IFN-gamma-treated cells. This increase was also reflected at the RNA level in that IFN-gamma treatment resulted in higher CAT transcripts. A computer homology search revealed a possible consensus sequence shared among different IFN-gamma-inducible genes.
Expression and role of the T cell receptor in early thymocyte differentiation in vitro.
Authors: Born W , McDuffie M , Roehm N , Kushnir E , White J , Thorpe D , Stefano J , Kappler J , Marrack P 
Published: December 2022

Abstract
Fetal thymus organ culture was used to study the expression and function of antigen-specific, major histocompatibility complex-restricted receptors on thymocytes. Receptor gene rearrangement and expression occurred de novo in organ culture indicating that these events are induced in the thymus itself, presumably in response to thymus-derived stimuli. During organ culture a population of immature thymocytes expressing low levels of receptors developed first, and then diminished as mature thymocytes with high levels of receptor expression appeared. Continuous culture with antireceptor antibody modulated receptor from the surfaces of immature thymocytes, but did not prevent their appearance or accumulation. By contrast, appearance of receptor-bearing mature thymocytes was prevented in the presence of antireceptor antibody. These results indicate that the receptor is not essential for the generation of immature thymocytes but is involved in the selection or maintenance of mature cells from this pool.
Antigen presentation by liver sinusoidal lining cells after antigen exposure in vivo.
Authors: Rubinstein D , Roska A K , Lipsky P E 
Published: December 2022

Abstract
The ability of liver sinusoidal lining cells (LSLC), a mixture of Kupffer cells and endothelial cells, to function as antigen-presenting cells (APC) was examined. Guinea pig LSLC were found to present antigen in vitro, albeit somewhat less effectively than a reference population of peritoneal exudate macrophages. The difference in APC function could not be explained by a deficiency of interleukin 1 (IL 1), as LSLC secreted IL 1 and expressed membrane-bound thymocyte stimulatory activity. The ability of LSLC to take up antigen from the portal blood in vivo and present it to primed T lymphocytes in vitro was also investigated. Trinitrophenyl-ovalbumin was injected intraportally into either strain 13 or strain 2 guinea pigs. The LSLC were subsequently isolated by collagenase digestion and density separation and assessed for the ability to induce proliferation of antigen-primed accessory cell-depleted syngeneic peritoneal exudate T lymphocytes in vitro. The in vivo antigen-pulsed LSLC were found to present antigen in vitro to primed T cells in an antigen-specific and genetically restricted manner. T cell DNA synthesis induced by antigen-bearing LSLC could be augmented by coculture with additional accessory cells, but not IL 1-containing macrophage supernatants. Enhancement of responsiveness was not genetically restricted. The demonstration that LSLC can take up, process, and retain antigen in vivo and present it to primed T cells in vitro suggests that LSLC are capable of contributing to the immune response to antigens appearing in portal blood.
Regulation of B cell maturation and differentiation. I. Suppression of pokeweed mitogen-induced B cell differentiation by tumor necrosis factor (TNF).
Authors: Kashiwa H , Wright S C , Bonavida B 
Published: December 2022

Abstract
Growth and differentiation of B cells into Ig-secreting plasma cells is regulated by both T cells and macrophages and/or their secreted factors. Although the regulatory role of various cell-derived factors has been examined, the involvement of the macrophage-derived factor, TNF, in human B cell growth and differentiation has not yet been investigated. In the present study we examine the role of rTNF in polyclonal B cell response of human PBL induced by PWM. The addition of rTNF at the initiation of the culture resulted in the dose-dependent inhibition of the generation of both IgG and IgM PFC. Inhibition of PFC development followed the same dose response as rTNF-mediated cytotoxicity against a TNF-sensitive tumor target. The mechanism of rTNF-mediated suppression was examined in different experimental systems. Recombinant TNF did not affect the viability or proliferation of either the T cell or B cell subpopulations, suggesting that TNF does not mediate its suppressive effect by cytotoxic mechanisms. Kinetic studies in which rTNF was added at different times after initiation of culture indicated that inhibition can be observed as late as 4 days of culture and suggested that TNF acts at a late phase of the growth and differentiation pathway of B cells. In further studies we examined the cellular level of TNF-mediated suppression. The addition of rTNF to supernatants containing helper factors and enriched B cells resulted in no inhibition, suggesting that TNF does not act at the B cell level. This was confirmed by demonstrating that rTNF does not inhibit spontaneous PFC development by the CESS B cell line. The effect of TNF on T cell subpopulations was examined by using normal or irradiated T cells, which inactivate suppressor cells. Addition of rTNF to B cells combined with either T cell population suppressed both IgG and IgM PFC development, indicating that the target cell for suppression is the T helper cell but not ruling out an effect on macrophages or the T suppressor cells. Combined, the observed results demonstrate that rTNF suppresses PWM-induced B cell differentiation without affecting B cell proliferation. TNF appears to mediate the suppression by acting directly on T helper cells or else by regulating the production of factors controlling T cell activation and lymphokine secretion.
In vitro regulation of IgA subclass production. III. Selective transformation of IgA1 producing cells by Epstein-Barr virus.
Authors: Conley M E , Chan M A , Sigal N H 
Published: December 2022

Abstract
In past experiments, using limited dilution analysis, we have demonstrated that a high percentage of immunoglobulin-secreting clones derived from Epstein-Barr virus- (EBV) stimulated lymphocytes secrete IgA. To further characterize the IgA produced by these clones, the IgA subclass of supernatants from clones stimulated 4 to 6 wk previously with EBV was determined by radioimmunoassay. All of 17 IgA-producing clones secreted IgA1; none secreted IgA2. Because we have shown that surface IgM+ (sIgM+) B cells are an enriched source of IgA2 plasma cell precursors, panning techniques were used to purify sIgM+ B cells from tonsils. Of 103 clones derived from these sIgM+ B cells, 102 secreted IgA1 and only one secreted IgA2. The relative absence of IgA2-producing clones could not be attributed to an absence of EBV receptors on IgA2 cells. A mean of 84 +/- 4% of freshly isolated IgA2 B cells and 78 +/- 6% of IgA1 B cells could be stained with a monoclonal antibody binding the EBV receptor; and there was no failure of EBV to infect IgA2 plasma cells precursors. Of IgA2 plasma cells derived from peripheral blood lymphocytes stimulated 7 days previously with EBV, 54 +/- 7% were positive for the EBV nuclear antigen, compared with 54 +/- 18% of IgA1 plasma cells from the same cultures. Seven days after EBV stimulation, a mean of 25% of the total IgA plasma cells were positive for cytoplasmic IgA2, whereas by 21 days after stimulation only 7% were positive for IgA2. This shift in the proportions of IgA1 and IgA2 plasma cells could be attributed to a failure of the IgA2 plasma cell number to increase after 10 days in culture. There was no evidence for selective suppression of IgA2 production by T cells or selective lysis of IgA2 plasma cells by infectious EBV particles. These results demonstrate that although precursors for both IgA1- and IgA2-producing cells can be stimulated to differentiate in response to EBV, there is preferential transformation of IgA1-producing cells.
Studies on the molecular nature of human interleukin 1.
Authors: Auron P E , Warner S J , Webb A C , Cannon J G , Bernheim H A , McAdam K J , Rosenwasser L J , LoPreste G , Mucci S F , Dinarello C A 
Published: December 2022

Abstract
Adherent human blood monocytes were stimulated with heat-killed Staphylococcus albus or Escherichia coli lipopolysaccharide in the presence of 35S-methionine-, [3H]leucine-, or 14C-labeled amino acids. After incubation, interleukin 1 (IL 1) activity in the supernatant medium was purified over an anti-human IL 1 immunoadsorbent followed by gel filtration and chromatofocusing. The purity of the IL 1 was assessed by fluorography of one- and two-dimensional SDS-polyacrylamide gel electrophoresis. Isoelectric and chromatofocusing of low m.w. proteins (less than 20,000 m.w.) revealed three charged 18,000 m.w. species of IL 1 with approximate pI's of 7, 6, and 5, with the most abundant form at pI 7. During the purification procedures, lymphocyte co-mitogenic activity, fever in rabbits, and prostaglandin E2 release from dermal fibroblasts co-eluted in the same fractions. In addition, these fractions were active when injected into endotoxin-resistant C3H/HeJ mice for the production of fever, the induction of serum amyloid A protein, a decrease in serum iron concentration, and an increase in the number of circulating neutrophils. Fluorography revealed homogeneous bands with an m.w. of about 18,000 which correlated with these biological activities. The specific activity of the pI 6 or 5 IL 1, as judged by the ratio of T cell co-mitogenic activity to incorporated radiolabeled amino acid, was at least 10-fold greater than that observed for the pI 7 form. This result suggests that the amino acid compositions of the two 18,000 m.w. acidic forms are unrelated to the pI 7 species. These results also demonstrate that the pI 7 human monocyte IL 1 is the predominant 18,000 m.w. form synthesized and, furthermore, that homogeneous pI 7 IL 1 exhibits multiple biological properties on various tissues by modulating immunologic, inflammatory, metabolic, and neurologic functions. Data are also presented for the existence of a high m.w. (32,000) human pro-IL 1 molecule as the predominant monocytic intracellular form. This pro-IL 1 is degraded artifactually during isolation to lower m.w. forms in the presence of an extracellular serine protease activity. These data are consistent with a model for IL 1 secretion in which pro-IL 1 is first synthesized within the cell and is processed during or after extracellular transport.
UV-irradiated epidermal cells produce a specific inhibitor of interleukin 1 activity.
Authors: Schwarz T , Urbanska A , Gschnait F , Luger T A 
Published: December 2022

Abstract
UV irradiation of epidermal cells (EC) in vitro and in vivo leads to an enhanced synthesis of the immunostimulating cytokine interleukin 1 (IL 1). However, UV exposure in vivo also results in local as well as systemic immunosuppression. Therefore, it was tested whether UV-exposed murine EC in culture in addition to IL 1 release an inhibitor of IL 1 activity. Supernatants of UV-irradiated BALB/c EC and of a transformed keratinocyte cell line (Pam 212) were evaluated for their ability to suppress IL 1-mediated thymocyte proliferation. Crude supernatants derived from either UV-exposed or unirradiated EC did not interfere with IL 1 activity. When supernatants were subjected to HPLC gel filtration, fractions eluting at approximately 40 kD significantly blocked the activity of EC-derived IL 1 and murine recombinant IL 1. The release of this inhibitory cytokine (EC-derived contra-IL 1 [EC-contra-IL 1]) was confined to UV-exposed BALB/c or Pam 212 keratinocytes, since no inhibitory activity was detected in supernatants of unirradiated cells. EC-contra-IL 1 also blocked IL 1-induced fibroblast proliferation but did not suppress IL 2 or IL 3 activity. Moreover, EC-contra-IL 1 did not inhibit spontaneous proliferation of a variety of cell lines (Pam 212, P388D1, L 929, EL 4). With the use of chromatofocusing EC-contra-IL 1 exhibited a pI of 8.8, and upon reversed-phase chromatography it eluted within three distinct peaks. Therefore, murine UV-exposed EC, in addition to the production of immunoenhancing cytokines, also may release immunosuppressing mediators and thereby participate in UV-induced immunosuppression. These findings further support the notion that the epidermis may not only be considered as a simple barrier against harmful agents but represents an active element of the immune system.