bluuebunny/crossref_metadata_2025 huggingface dataset:
Amelioration of B16F10 melanoma lung metastasis in mice by a combination therapy with indomethacin and interleukin 2.
Authors: Parhar R S , Lala P K
Published: June 2004

Our earlier work revealed that PGE-mediated inactivation of NK cells in tumor-bearing mice by host macrophages promoted spontaneous lung metastasis that could be prevented or ameliorated by chronic indomethacin therapy. Since PGE was found to suppress the in vitro development and/or activation of a family of tumoricidal lymphocytes such as CTL, NK, and LAK cells by one or both of two mechanisms, that is to say, a down regulation of IL-2-R and an inhibition of IL-2 production, the present study tested whether a combined therapy with indomethacin and IL-2 was more effective than one with indomethacin or IL-2 alone in ameliorating established experimental lung metastasis. B6 mice injected intravenously with 10(6) highly metastatic B16F10 melanoma cells showed profuse micrometastases in the lungs by day 5, and macrometastases by day 10 which were confluent on day 21. Chronic indomethacin therapy by the oral route (14 micrograms/ml in drinking water) starting on day 0 or day 5, or a single round of IL-2 therapy (25,000 U rIL-2, every 8 h for 5 d on days 10-14) reduced the number of metastatic nodules by two-thirds (from a median of 473 in control mice receiving vehicles alone) by day 21. A single round of IL-2 as above, combined with either protocol of indomethacin therapy, completely or nearly completely irradicated the lung metastases, corroborated by a histological examination. An evaluation of splenic killer cell activity measured with a 4-h 51Cr-release assay against NK-sensitive YAC-1 lymphoma and B16F10 melanoma or NK-resistant thymic lymphoma 9705 targets revealed negligible activity in control tumor-bearing mice, and a good restoration of activity against NK-sensitive targets with either protocols of indomethacin therapy. IL-2 alone or a combination of IL-2 and indomethacin given by either protocol generated strong killer activity against all these targets, most marked with the combination therapy. Splenic killer cell phenotype in normal as well as all treated animals was ASGM1+, Thy-1-, and Lyt-2-. The combination therapy resulted in the strongest mononuclear cell infiltration in the lungs, with areas of young granulation tissue suggestive of repair sites of original metastases.
Interleukin 2 high-affinity receptor expression requires two distinct binding proteins.
Authors: Teshigawara K , Wang H M , Kato K , Smith K A
Published: June 2004

A cell line established from a patient with acute lymphoblastic leukemia was found to express IL-2 binding sites with a novel, intermediate affinity compared with the characteristic high-affinity IL-2-receptors and low-affinity IL-2 binding sites described previously. Clones were isolated from this cell line that displayed solely this new IL-2-binding protein, and were found to be unreactive with anti-Tac, the mAb that competes with IL-2 for binding. Moreover, these same cloned cells did not express mRNA detectable by hybridization with radiolabeled cDNA encoding the Tac protein. In contrast, the original cell line and similar clones expressed low levels of Tac mRNA and cell surface Tac antigen, both of which could be augmented by exposure to medium conditioned by adult T leukemia cell lines. Particularly noteworthy, induction of Tac antigen expression was paralleled by an increase in the number of high-affinity IL-2-R detectable. Since the expression of the Tac antigen protein by itself makes only for low-affinity IL-2 binding, these data prompted a reevaluation of the structural composition of high-affinity IL-2-R. Analysis of the IL-2-binding proteins expressed by leukemic cell lines lacking high-affinity receptors revealed only a single protein, larger than the Tac antigen protein (Mr = 75,000 vs. 55,000). In contrast, clones induced to express high-affinity receptors had clearly both of these IL-2-binding proteins. Moreover, when IL-2 binding to normal T cells was performed under conditions that favored the proportion of high-affinity receptors occupied, two distinct proteins identical to those already identified on the leukemic cells could be crosslinked covalently to radiolabeled IL-2. The interpretations derived from these varied, assembled data, point to two IL-2-binding proteins, both of which are required for high-affinity IL-2 binding.
Autoantibodies to neurofibrillary tangles and brain tissue in Alzheimer's disease. Establishment of Epstein-Barr virus-transformed antibody-producing cell lines.
Authors: Gaskin F , Kingsley B S , Fu S M
Published: June 2004

Multiple EBV-transformed B cell lines were established from five patients with a clinical diagnosis of Alzheimer's disease (AD) and six age-matched controls. The supernatants were screened for antibody activity against SDS-treated isolated neurofibrillary tangles (NFT). Reactive supernatants were identified from both the AD and control group. The frequencies of anti-NFT antibody-secreting lines were 6.3 and 1.6% for the AD and the control groups, respectively. A proportion of these supernatants also stained NFT in situ and neurons and/or glia in sections of the frontal and the temporal cortexes of autopsied AD and normal brains, as well as cells from three cell lines (HeLa, fibroblast, and neuroblastoma). Several patterns of staining were revealed by these supernatants, indicating different reactive antigens. One supernatant stained NFT and astrocytes in sections from AD brains. It did not stain sections from two normal brains. This cell line is the result of the immortalization of a circulating B cell making antibody specific for an antigen in AD. The present approach may provide new insights in the pathogenesis of AD.
A 275 basepair fragment at the 5' end of the interleukin 2 gene enhances expression from a heterologous promoter in response to signals from the T cell antigen receptor.
Authors: Durand D B , Bush M R , Morgan J G , Weiss A , Crabtree G R
Published: June 2004

Using a transient transfection assay, we have defined the sequences required for the activation of the IL-2 gene in response to signals from the T cell antigen receptor. To do so we have transfected the human T cell line Jurkat with hybrid DNA constructs in which fragments from the IL-2 gene are linked to an indicator gene. The indicator gene product, as well as IL-2 production from the endogenous IL-2 gene were assayed after activation of the transfected Jurkat cells by various stimuli. We have demonstrated that a 275 bp fragment stretching from 52 to 326 bp upstream of the IL-2 gene transcription initiation site is required for expression of the linked indicator gene. This IL-2 gene fragment has several of the characteristics of a transcriptional enhancer element, in that it functions in both orientations and will enhance the expression from the promoter of an unrelated gene. Such enhancement occurred only after activation of Jurkat cells through the T cell antigen receptor. More specifically, this 275 bp fragment activated the expression of a linked gene after binding of a monoclonal antibody to the Jurkat T cell antigen receptor in the presence of PMA. In addition, calcium ionophore, which circumvents antigen receptor binding in T cell activation, induced the expression of the linked gene through this 275 bp sequence, in the presence of PMA. Finally, in a mutant Jurkat cell line lacking T3/antigen receptor complexes at the cell surface, no expression due to the IL-2 5' flanking region was seen after exposure to antibody to the T cell antigen receptor plus PMA or to PHA plus PMA. In contrast, calcium ionophore plus PMA did induce the expression of a linked gene through the IL-2 5' flanking region in the mutant Jurkat cell line. The responsiveness of the transfected hybrid genes containing the IL-2 regulatory region paralleled the expression of the endogenous IL-2 gene, as determined by IL-2 bioassays. We conclude that the 275 bp IL-2 sequence (-326 to -52 bp) is a target for the signal pathway originating at the T cell antigen receptor. Definition of this 275 bp target sequence should now permit the isolation of the molecules that bind to and activate the IL-2 gene.
Interleukin-HP1, a T cell-derived hybridoma growth factor that supports the in vitro growth of murine plasmacytomas.
Authors: Van Snick J , Vink A , Cayphas S , Uyttenhove C
Published: June 2004

We have recently described the purification and NH2-terminal amino acid sequence of a T cell-derived hybridoma growth factor that was provisionally designated interleukin-HP1 (IL-HP1). Here we report that a T cell supernatant containing high titers of this hybridoma growth factor considerably facilitated the establishment of primary cultures of murine plasmacytomas. Most plasmacytoma cell lines derived from such cultures remained permanently dependent on IL-HP1-containing T cell supernatant for both survival and growth in vitro. These cell lines, however, retained their ability to form tumors in irradiated pristane-treated mice. Analytical fractionation of a T cell supernatant rich in IL-HP1 by either gel filtration, isoelectric focusing, or reversed-phase HPLC revealed the existence of only one plasmacytoma growth factor activity that strictly copurified with IL-HP1, strongly suggesting the identity of both factors. This conclusion was further supported by the finding that IL-HP1 purified to homogeneity supported the growth of both B cell hybridomas and plasmacytomas. For half-maximal growth, plasmacytomas, however, required a concentration of IL-HP1 of approximately 30 pM, which is approximately 200 times higher than that required by B cell hybridomas. A clear difference in the specificity of IL-HP1 and B cell stimulatory factor 1 (BSF-1) was demonstrated by the finding that IL-HP1-dependent plasmacytomas did not survive in the presence of BSF-1, whereas helper T cell lines that proliferated in the presence of BSF-1 failed to respond to IL-HP1.
The human natural anti-Gal IgG. III. The subtlety of immune tolerance in man as demonstrated by crossreactivity between natural anti-Gal and anti-B antibodies.
Authors: Galili U , Buehler J , Shohet S B , Macher B A
Published: June 2004

A well-defined antigen/antibody system was used to evaluate the effect of immune tolerance on the spectrum of specificities of natural antibodies. The antibody used in this study, anti-Gal, is a naturally occurring, polyclonal IgG that constitutes 1% of the circulating IgG in humans. We have previously shown that anti-Gal, purified from AB sera, specifically interacts with glycosphingolipids bearing a Gal alpha 1----3Gal epitope, but not with the closely related B antigen in which the penultimate galactose of the Gal alpha 1----3Gal epitope is fucosylated Gal alpha 1----3(Fuc alpha 1----2)Gal. This narrow specificity was assumed to be the result of an effective immune tolerance mechanism that prevents the expression of antibody clones that can recognize both the Gal alpha 1----3Gal and the self B epitopes. If the assumption that immune tolerance determines the range of anti-Gal specificity is correct, then anti-Gal from individuals lacking the B antigen (A and O blood types) would be expected to interact with both Gal alpha 1----3Gal and Gal alpha 1----3(Fuc alpha 1----2)Gal epitopes. In this study, anti-Gal from the serum of individuals of various blood types was purified by affinity chromatography on Gal alpha 1----3Gal adsorbent and tested for its reaction with the B antigen. Whereas anti-Gal from AB and B individuals only reacted with Gal alpha 1----3Gal epitopes, anti-Gal from A and O individuals reacted with both Gal alpha 1----3Gal and B epitopes. Furthermore, it was determined that the majority of anti-B reactivity in A and O individuals is in fact anti-Gal antibodies capable of recognizing both Gal alpha 1----3Gal and B epitopes. It can be concluded from these results that immune tolerance accurately controls the spectrum of natural antibody specificities by preventing the production of antibody clones that can interact with self antigens.
Unspecific binding of group B streptococcal cocytolysin (CAMP factor) to immunoglobulins and its possible role in pathogenicity.
Authors: Jürgens D , Sterzik B , Fehrenbach F J
Published: June 2004

The protein B of group B streptococci can bind in a nonimmune reaction to Ig of the IgG and IgM classes of various mammalian species (i.e., human, mouse, rabbit, and bovine). Protein B binding involves the Fc parts of both IgG and IgM molecules. Monoclonal or polyclonal IgG or IgM and the IgM-FC5 mu fragment of human myeloma protein combined with the protein B thereby inhibiting protein B-induced hemolysis in the CAMP reaction. The protein B/Ig complex can be dissociated with 1% Triton or guanidine-HCl (6 M). Mice infected intraperitoneally with sublethal doses of group B streptococci (GBS) and that received seven repeated intravenous injections of highly purified protein B during the first 9 h of infection developed fatal septicemia within 24 h with colony counts of up to 10(8) CFU/ml in the blood. Animals treated in the same way with either PBS or trypsinized protein B recovered. The protein B itself was not pathogenic when injected into healthy mice. Tissue sections of liver or spleen from mice infected with a lethal dose of GBS revealed the presence of protein B together with large numbers of cocci when stained by the peroxidase method using specific antibodies raised against purified protein B in the rabbit.
Lamin B autoantibodies in sera of certain patients with systemic lupus erythematosus.
Authors: Reeves W H , Chaudhary N , Salerno A , Blobel G
Published: June 2004

Sera from four patients with systemic lupus erythematosus containing antibodies that yield nuclear rim staining of HEp-2 cells by indirect immunofluorescence were identified and characterized. Each serum contained autoantibodies reacting strongly with lamin B on western blots. One of the four sera displayed weaker reactivity with lamins A and C, while the other three displayed only minimal reactivity with lamins A and C. Titers of antilamin antibodies ranged from 1:1,250 to 1:36,250. Two of the sera also reacted at a dilution of 1:20 with cytoplasmic filaments of PTK-2 cells, suggesting that a small fraction of the autoantibodies in these sera may bind to alpha-helical domains of the lamins that are homologous to those of intermediate filaments. The majority of the antilamin antibodies in these patients' sera are specific for portions of the lamin B molecule that are not homologous to lamins A and C, however. The findings suggest that autoantibodies to the nuclear lamina may, in some instances, be responsible for a rim pattern in the fluorescent antinuclear antibody assay. In addition, autoantibodies to the nuclear lamina in sera of certain patients with systemic lupus erythematosus may be useful for defining the molecular structure and biological functions of lamin B, as well as for studying mechanisms of autoimmunity.
Prolonged survival of actively enhanced rat renal allografts despite accelerated cellular infiltration and rapid induction of both class I and class II MHC antigens.
Authors: Armstrong H E , Bolton E M , McMillan I , Spencer S C , Bradley J A
Published: June 2004

Administration of 1 ml of donor whole blood 7 d before renal transplantation produces long-term (greater than 100 d) graft survival in the DA (RT1a) into PVG (RT1c) rat strain combination. Using this model, the pattern and phenotype of infiltrating leukocytes were examined in rejecting and enhanced renal allografts, at days 1, 3, 5, and 7 after transplantation, by immunohistologic techniques. Paradoxically, enhanced grafts showed a more rapid and substantial leukocyte infiltrate, the phenotype of which was similar to that in rejecting grafts except for a reduced number of MRC OX-8+ cells and MRC OX-39+ cells. Graft infiltrating cells and splenocytes from transfused animals showed similar, although modest, levels of both nonspecific cytotoxicity and alloantigen-specific cytotoxicity. Immunohistologic analysis of MHC antigen distribution within the allograft revealed, unexpectedly, that enhanced grafts underwent an accelerated and extensive induction of both donor class I and class II MHC antigens. These findings were confirmed by allospecific quantitative absorption analysis, which showed severalfold increases in class I and class II MHC antigens by day 3 in enhanced grafts but not until day 5 in rejecting grafts. An additional observation was the more rapid disappearance of donor interstitial cells from enhanced grafts. These findings emphasize the overwhelming suppressive effect induced by an organ allograft after preoperative blood transfusion despite the associated induction of large numbers of potential effector cells and increased target antigen density within the graft.
The T cell antigen receptor complex expressed on normal peripheral blood CD4-, CD8- T lymphocytes. A CD3-associated disulfide-linked gamma chain heterodimer.
Authors: Lanier L L , Federspiel N A , Ruitenberg J J , Phillips J H , Allison J P , Littman D , Weiss A
Published: June 2004

IL-2-dependent cell lines were established from normal peripheral blood T lymphocytes that express neither CD4 nor CD8 differentiation antigens. CD3+,4-,8- cell lines from 15 different donors failed to react with WT31, an mAb directed against the T cell antigen receptor alpha/beta heterodimer. Anti-Leu-4 mAb was used to isolate the CD3/T cell antigen receptor complex from 125I-labeled CD3+,4-,8- (WT31-) T cells. Using detergent conditions that preserved the CD3/T cell antigen receptor complex, an approximately 90 kD disulfide-linked heterodimer, composed of approximately 45- and approximately 40- (or approximately 37-) kD subunits, was coimmunoprecipitated with the invariant 20-29-kD CD3 complex. Analysis of these components by nonequilibrium pH gradient electrophoresis indicated that the approximately 40-kD and approximately 37-kD subunits were similar, and quite distinct from the more basic approximately 45-kD subunit. None of these three subunits reacted with an antibody directed against a beta chain framework epitope. Heteroantiserum against a T cell receptor gamma chain peptide specifically reacted with both the approximately 37- and approximately 40-kD CD3-associated proteins, but not with the approximately 45-kD subunit. CD3+,4-,8- cells failed to transcribe substantial amounts of functional 1.3-kb beta or 1.6-kb alpha mRNA, but produced abundant 1.6-kb gamma mRNA. Southern blot analysis revealed that these CD3+,4-,8- cell lines rearranged both gamma and beta genes, and indicated that the populations were polyclonal. The expression of a CD3-associated disulfide-linked heterodimer on CD3+,4-,8- T cell lines established from normal, adult peripheral blood contrasts with prior reports describing a CD3-associated non-disulfide-linked heterodimer on CD3+/WT31- cell lines established from thymus and peripheral blood obtained from patients with immunodeficiency diseases. We propose that this discrepancy may be explained by preferential usage of the two C gamma genes in T lymphocytes.
Proof that Sn-protoporphyrin inhibits the enzymatic catabolism of heme in vivo. Suppression of 14CO generation from radiolabeled endogenous and exogenous heme sources.
Authors: Landaw S A , Sassa S , Drummond G S , Kappas A
Published: June 2004

Sn-protoporphyrin (SnPP) suppresses generation of 14CO from hepatic heme labeled with delta-aminolevulinic acid (5-[14C]ALA) or from infused [14C]hemin in rats. SnPP administered 1 h before administration of 5-[14C]ALA virtually abolished the peak output of 14CO occurring 2-3 h after injection of this heme precursor, and during the succeeding 12 h reduced 14CO excretion by approximately 61% compared with controls. When [14C]hemin was infused, SnPP diminished 14CO excretion by approximately 50%. These findings, derived from experiments using radiolabeled endogenous and exogenous heme sources, establish conclusively that the synthetic metalloporphyrin SnPP inhibits the oxidative degradation of heme in the intact animal.
Internalization of interleukin 2 is mediated by the beta chain of the high-affinity interleukin 2 receptor.
Authors: Robb R J , Greene W C
Published: June 2004

High-affinity IL-2-R correspond to a membrane receptor complex composed of two different IL-2-binding proteins, the Tac antigen (alpha chain) and a 70-75 kD beta chain. Using cell lines that express either the alpha or the beta protein, we demonstrate that IL-2 internalization occurs when ligand is bound to the isolated beta chain, but not when it is bound to the isolated alpha chain. The kinetics of IL-2 internalization mediated by the intermediate-affinity beta chain were nearly identical to those of the high-affinity alpha/beta heterodimer (t1/2 of 10-15 min), and each type of receptor targeted the bound IL-2 for intracellular degradation in lysosomes. The beta chain thus appeared to provide the essential element necessary for ligand internalization by both types of IL-2-R.
The macrophage response to central and peripheral nerve injury. A possible role for macrophages in regeneration.
Authors: Perry V H , Brown M C , Gordon S
Published: June 2004

Using mAbs and immunocytochemistry we have examined the response of macrophages (M phi) after crush injury to the sciatic or optic nerve in the mouse and rat. We have established that large numbers of M phi enter peripheral nerves containing degenerating axons; the M phi are localized to the portion containing damaged axons, and they phagocytose myelin. The period of recruitment of the M phi in the peripheral nerve is before and during the period of maximal proliferation of the Schwann cells. In contrast, the degenerating optic nerve attracts few M phi, and the removal of myelin is much slower. These results show the clearly different responses of M phi to damage in the central and peripheral nervous systems, and suggest that M phi may be an important component of subsequent repair as well as myelin degradation.
Purification of human gamma interferon receptors by sequential affinity chromatography on immobilized monoclonal antireceptor antibodies and human gamma interferon.
Authors: Aguet M , Merlin G
Published: June 2004

mAbs against human IFN-gamma (huIFN-gamma) receptors were obtained by immunizing a BALB/c mouse with eluates from immobilized recombinant huIFN-gamma (rhuIFN-gamma) on which lysates of enriched Raji cell membranes had been adsorbed. mAbs were selected for competitive inhibition of receptor binding of 125I-labeled rhuIFN-gamma. The following additional properties suggest that these antibodies are specific for huIFN-gamma receptors: they bind to the surface of human cells expressing IFN-gamma receptors but not to heterologous cells; this binding is inhibited competitively by addition of rhuIFN-gamma; the number of binding sites revealed by direct binding of 125I-labeled rhuIFN-gamma correlates with the amount of antigen recognized by the mAbs on different cell lines. A Triton X-100 extract of a membrane-enriched fraction of human Raji cells was affinity purified with these mAbs and the eluates from such columns were further purified on immobilized rhuIFN-gamma. As revealed by SDS-PAGE, the final eluate contained two major protein bands with approximate Mr of 90,000 (p90) and 50,000 (p50), respectively. Both proteins were able to specifically bind 125I-labeled rhuIFN-gamma upon electroblotting to nitrocellulose. This binding could be inhibited by the huIFN-gamma receptor mAbs, suggesting that the same epitopes are recognized on p90, p50, and on the cell surface. Therefore, these proteins most likely represent at least a part of huIFN-gamma receptors.
Antigenic variation of cloned Plasmodium fragile in its natural host Macaca sinica. Sequential appearance of successive variant antigenic types.
Authors: Handunnetti S M , Mendis K N , David P H
Published: June 2004

The course of infection of Plasmodium fragile in its natural host, the toque monkey Macaca sinica, consists of a primary peak of parasitemia followed by several distinct, successive peaks of lower parasitemia. In the S+ host, the late intraerythrocytic asexual developmental stages of P. fragile induce the expression of antigens on the surface of infected erythrocytes, which could be detected using the technique of surface immunofluorescence. Immunofluorescence using unfixed erythrocytes in suspension has shown that antigens are recognized by immune serum on the surface of the erythrocytes infected with more mature stages of the parasite. These antigens undergo variation, each successive peak of parasitemia being characterized by a different variant antigenic type (VAT). The appearance of the successive VATs occurs in a sequential manner, following the same order in different sets of animals. This constitutes the first example of a sequential expression of antigens in a malaria parasite; it indicates that, in P. fragile, antigenic variation is not the result of random mutations selected by antibody. Parasite-induced antigens on the surface of infected erythrocytes could not be detected in the S- host. However, when nonexpressing parasites from the S- host were transferred by blood passage into a naive S+ animal, they began to express antigens on the surface of infected erythrocytes within two erythrocytic cycles. We have demonstrated that the ability of S- parasites to switch to a particular VAT when passaged into a S+ animal changes during the course of an infection in the S- animal, indicating that, although surface antigens are not expressed, the processes leading to antigenic variation occurs even in the S- host. Antibodies directed against these surface antigens inhibit the growth of intra-erythrocytic parasites. The growth inhibition effects of antibodies are also variant specific, indicating that these variant surface antigens are functionally important for parasite survival.
Gonococcal pilin variants in experimental gonorrhea.
Authors: Swanson J , Robbins K , Barrera O , Corwin D , Boslego J , Ciak J , Blake M , Koomey J M
Published: June 2004

When pilus+ Gc were introduced into a male subject's urethra, they gave rise to pilus+ variants whose pilin mRNAs differed from that of input Gc. The differences stemmed from the Gc genome's single complete pilin gene having undergone gene conversion by different partial pilin genes' sequences and by different length stretches of a single partial pilin gene. In some instances, the variant's pilin mRNA appeared to reflect two independent gene-conversion events that used sequences from two different partial pilin genes. The resulting variants' pilins exhibited antigenic differences compared with the pilin polypeptide of input Gc; these differences were discernible by immunoblotting with mAbs. Amino acid and antigenic changes occurred in a segment of the variants' pilin polypeptides that previously was thought to be conserved or constant in sequence.
Dissociation of membrane binding and lytic activities of the lymphocyte pore-forming protein (perforin).
Authors: Young J D , Damiano A , DiNome M A , Leong L G , Cohn Z A
Published: June 2004

Granules isolated from CTL and NK cells contain a cytolytic pore-forming protein (PFP/perforin). At low temperatures (on ice), PFP binds to erythrocyte membranes without producing hemolysis. Hemolysis occurs when the PFP-bound erythrocytes are warmed up to 37 degrees C, which defines a temperature-dependent, lytic (pore-formation) step distinct from the membrane-binding event. Ca2+ and neutral pH are required for both membrane binding and pore formation by PFP. Serum, LDL, HDL, and heparin inhibit the hemolytic activity of PFP by blocking its binding to lipid membranes. Lysis by PFP that has bound to erythrocyte membranes is no longer susceptible to the effect of these inhibitors. The hemolytic activities associated with intact granules and solubilized PFP show different requirements for Ca2+ and pH, indicating that cytolysis produced by isolated granules may involve an additional step, possibly fusion of granules with membranes. It is suggested that three distinct Ca2+- and pH-dependent events may be involved during cell killing by CTL and NK cells: fusion of cytoplasmic granules of effector cells with their plasma membrane, releasing PFP from cells; binding of the released PFP to target membranes; and insertion of monomers and the subsequent formation of lytic pores in the target membrane. The serum-mediated inhibition of membrane binding by PFP could prevent the accidental injury of bystander cells by cell-released PFP, but would allow cytolysis to proceed to completion once PFP has bound to the target membrane.
Deacylated lipopolysaccharide inhibits neutrophil adherence to endothelium induced by lipopolysaccharide in vitro.
Authors: Pohlman T H , Munford R S , Harlan J M
Published: June 2004

Selective deacylation of the nonhydroxylated fatty acids from S. typhimurium LPS by an acyloxyacyl hydrolase isolated from leukocytes reduces toxic activity of LPS in vivo. We examined the effect of deacylated LPS on neutrophil adherence to human umbilical vein endothelial cells (HUVE). Pretreatment of HUVE with LPS (13 ng/ml for 4 h) produced a marked increase in the adherence of subsequently added neutrophils. In contrast, there was no increase in the adherence of neutrophils to HUVE pretreated with deacylated LPS (up to 260 ng/ml for 4 h). Neutrophil adherence to HUVE pretreated with LPS decreased as the degree of LPS deacylation increased. Deacylated LPS was not only itself inactive, but it inhibited neutrophil-endothelial interactions induced by LPS. Neutrophil adherence to HUVE pretreated with LPS was inhibited by deacylated LPS in a dose-dependent manner. Complete inhibition of adherence was observed at a 20:1 ratio (wt/wt) of deacylated LPS to LPS. Significantly, inhibition of neutrophil adherence to HUVE pretreated with LPS was observed even when deacylated LPS was added to HUVE up to 60 min after LPS. Deacylated LPS, however, did not inhibit neutrophil adherence induced by pretreatment of HUVE with IL-1 or TNF-alpha. We conclude that enzymatic deacylation of the nonhydroxylated fatty acids of LPS abolishes the ability of LPS to induce surface expression of a neutrophil adherence promoting activity in HUVE. Furthermore, deacylated LPS inhibits neutrophil adherence to HUVE induced by LPS, perhaps by preventing the interaction of LPS with a specific cell-surface or intracellular target.
Human recombinant interleukin 4 induces Fc epsilon receptors (CD23) on normal human B lymphocytes.
Authors: Defrance T , Aubry J P , Rousset F , Vanbervliet B , Bonnefoy J Y , Arai N , Takebe Y , Yokota T , Lee F , Arai K
Published: June 2004

Human rIL-4 is able to induce the expression of low-affinity receptors for IgE (Fc epsilon RL/CD23) on resting B lymphocytes, as determined by the binding of either the anti Fc epsilon RL/CD23-specific mAb 25 or IgE. Stimulation of B cells with insolubilized anti-IgM antibody increases the number of cells expressing Fc epsilon RL/CD23 upon culturing with IL-4 and enhances the level of Fc epsilon RL/CD23 expression on these cells. Fc epsilon RL/CD23 induction is specific for IL-4 since IL-1 alpha, IL-2, IFN-gamma, B cell-derived B cell growth factor (BCGF), and a low-molecular-weight BCGF were ineffective. IFN-gamma strongly inhibited the induction of Fc epsilon RL/CD23 by IL-4.
Development of fetal thymocytes in organ cultures. Effect of interleukin 2.
Authors: Skinner M , Le Gros G , Marbrook J , Watson J D
Published: June 2004

Most fetal thymocytes from 14-d mouse embryos are Thy-1+, L3T4-, Ly-2-, and express the receptor for interleukin 2 (IL-2). The development of thymocytes has been followed in fetal thymus organ cultures. When fetal thymus from 14-d embryos were cultured for a 6-d period, thymocytes increased in number 20-40-fold, and 95% became Thy-1+, L3T4+, Ly-2+. The addition of IL-2 to organ cultures of 14-d fetal thymus inhibited, in a dose-dependent manner, cell proliferation and the appearance of Thy-1+, L3T4+, Ly-2+ thymocytes. The addition of IL-2 also resulted in the appearance of a population of cells that were cytotoxic for syngeneic and allogeneic fetal thymocytes and syngeneic tumour targets. While the events that lead to the expression of the IL-2 receptor on 14-d fetal thymocytes are unknown, IL-2 in fetal thymus organ cultures inhibits the normal maturation of fetal thymocytes and raises the question of whether the cytotoxic cells that appear reflect selection through an alternative pathway of development.
Early genetic events in T cell development analyzed by in situ hybridization.
Authors: Pardoll D M , Fowlkes B J , Lechler R I , Germain R N , Schwartz R H
Published: June 2004

In situ hybridization was used to investigate the expression of T cell receptor (TCR) alpha, beta, and gamma mRNAs in developing fetal and adult precursor thymocytes. gamma transcription was observed at the earliest time tested (day 12), followed by beta 12 h later, and TCR alpha on day 16. The early beta transcripts appeared to be from unrearranged or incompletely rearranged (D-J-C) beta loci. V beta region transcription was first detectable on day 14 and transcription of different V beta genes was induced at different times. These results delineate a schedule sequence of TCR gene activation, which begins within 1 d after entry of stem cells into the fetal thymus.
High frequency of clonal immunoglobulin or T cell receptor gene rearrangements in acute myelogenous leukemia expressing terminal deoxyribonucleotidyltransferase.
Authors: Seremetis S V , Pelicci P G , Tabilio A , Ubriaco A , Grignani F , Cuttner J , Winchester R J , Knowles D M , Dalla-Favera R
Published: June 2004

Ig and T cell receptor rearrangements have been used as irreversible markers of lineage and clonality in the study of B- and T-lymphoid populations. We have addressed the issue of lymphoid lineage specificity of these rearrangements by analyzing a panel of 25 TdT- acute myelogenous leukemias, 13 TdT+ AMLs, and 4 TdT+ undifferentiated leukemias. We report that while gene rearrangements represent extremely rare events in classical TdT- AML (less than 8%), rearrangements of either the Ig or T beta locus or both were detectable in the majority of the TdT+ AMLs (greater than 60%), and rearrangements of both loci were detectable in all of the TdT+ undifferentiated leukemias. These data demonstrate a significant association between TdT expression and Ig or T beta gene rearrangements even outside the lymphoid lineage, further supporting a role for TdT in Ig and T cell receptor gene assembly. These data also indicate that a coordinated program of lymphoid gene expression involving TdT-CD7-expression and Ig/T beta rearrangements can be activated before myeloid commitment. Whether the activation of this program represents a normal, albeit rare, event in early myelopoiesis or a transformation-related event present only in leukemic cells remains to be determined.
Systemic autoimmune disease arises from polyclonal B cell activation.
Authors: Klinman D M , Steinberg A D
Published: June 2004

The number of B cells producing antibodies reactive with any of seven autoantigens or two conventional antigens was compared at the single-cell level to the total number of Ig-secreting B cells present in the spleens of NZB, MRL lpr/lpr, and BXSB autoimmune mice. The proportion of lymphocytes producing antibodies of each specificity, expressed as a percentage of the total B cell repertoire, was virtually identical among autoimmune and congenic nonautoimmune animals. Furthermore, B cells and serum antibodies reactive with conventional antigens increased commensurately with those reactive with autoantigens. These results indicate that systemic autoimmune diseases arise from polyclonal B cell activation.
Cholesterol requirement of P3-X63-Ag8 and X63-Ag8.653 mouse myeloma cells for growth in vitro.
Authors: Sato J D , Kawamoto T , Okamoto T
Published: June 2004

P3-X63-Ag8 and X63-Ag8.653 mouse myeloma cells have an absolute requirement for cholesterol for growth under serum-free conditions. This requirement can be satisfied by low density lipoprotein at 2-6 micrograms/ml or by BSA-bound cholesterol at 5-10 micrograms/ml. Cholesterol-independent variants can be selected after prolonged growth in low concentrations of serum.
Trichomonas vaginalis phenotypic variation occurs only among trichomonads infected with the double-stranded RNA virus.
Authors: Wang A , Wang C C , Alderete J F
Published: June 2004

Trichomonas vaginalis isolates were examined for the presence of viral double-stranded RNA (dsRNA) and the property of phenotypic variation. Only the heterogeneous isolates composed of mAb-reactive and -nonreactive organisms, as determined by indirect immunofluorescence and flow cytofluorometry, and capable of phenotypic variation possessed the dsRNA. Both the positive and negative phenotype subpopulations separated from the heterogeneous parent contained equal amounts of the dsRNA. Loss of the dsRNA upon prolonged in vitro cultivation always correlated with the lack of expression of the major immunogen. The data indicate a relationship between the presence of the dsRNA and the ability of the pathogenic human trichomonads to express immunogens on their surfaces and to undergo phenotypic variation.
Inducibility of Ia antigen on astrocytes by murine coronavirus JHM is rat strain dependent.
Authors: Massa P T , Brinkmann R , ter Meulen V
Published: June 2004

Inducibility of Ia molecules on cultivated astrocytes by JHM virus correlates with demyelinating disease susceptibility of animals from which these astrocytes are derived. On the contrary, class I induction of both astrocytes and oligodendrocytes occurs as a consequence of normal cultivation procedures in both susceptible and resistant strains. Increased expression of class I antigens on rat astrocytes and oligodendrocytes is not related to JHM viral infection as it is in the mouse. These data indicate that strain differences in Ia inducibility, rather than inducibility of class I antigens, by JHM virus may explain higher levels of T cell-mediated damage to myelin during infection in susceptible rat strains compared with resistant strains.
Emergence of immunoglobulin variants following treatment of a B cell leukemia with an immunotoxin composed of antiidiotypic antibody and saporin.
Authors: Glennie M J , McBride H M , Stirpe F , Thorpe P E , Worth A T , Stevenson G T
Published: June 2004

The potency and specificity of immunotoxins consisting of monoclonal antiidiotype conjugated to the ribosome-inactivating protein, saporin, have been evaluated in the treatment of guinea pig L2C B lymphocytic leukemia. The immunotoxins were therapeutically much more effective than their parent antibodies. Their specificity reflected that of their antiidiotype component. Although the leukemia emerged eventually in most animals treated with these conjugates, most of the cells showed altered Ig expression, which rendered them resistant to the therapy. Commonly, the emerging cells had lost mu heavy chain production, leaving them negative for intracellular, surface, and secreted IgM, but still positive for lambda light chain production. In addition, a minor group of L2C variants was identified in a protocol designed to detect mutants at very low frequency: here the cells were exposed in vitro to immunotoxin and, while still viable as judged by dye-exclusion, inoculated in large numbers into animals. In tumor that emerged under these circumstances, the majority of cells were again immunoglobulin-negative; however a minority exhibited IgM with an altered idiotype (Idiotope-loss variants), rendering them unreactive with immunotoxin. Immunotherapy with unmodified anti-Id antibody alone does not reveal these variants, and we suggest it is the increased selective force exerted by the highly potent immunotoxins that allow these minor nonreactive populations to emerge.
Possible pitfalls in the identification of glycophorin-binding proteins of Plasmodium falciparum.
Authors: van Schravendijk M R , Wilson R J , Newbold C I
Published: June 2004

Plasmodium falciparum proteins that bind to the putative erythrocyte receptor (glycophorin) have been identified in several laboratories by their ability to bind to glycophorin immobilized on aminoethyl-BioGel (AE-BioGel). We here report that several parasite proteins bind to AE-BioGel in the absence of coupled glycophorin. Binding is apparently due to the strong ion-exchange properties of the matrix, and is sensitive to ionic conditions such as the degree of equilibration of the matrix and the pH. The parasite proteins that bind to the blank column under appropriate conditions include proteins with the serological activities of S-antigen and Ag 23, which also bind to glycophorin-coupled AE-BioGel. In the light of these results, the glycophorin-binding specificity of these and other proteins reported to bind to glycophorin-coupled AE-BioGel will have to be reevaluated, preferably using a different support matrix.
Independent association of T cell receptor beta and gamma chains with CD3 in the same cell.
Authors: Koning F , Maloy W L , Cohen D , Coligan J E
Published: June 2004

We have demonstrated that the PEER cell line, which expresses a CD3-associated TCR gamma chain on the cell surface, synthesizes TCR beta chain intracellularly. A percentage of this TCR beta chain associates with the CD3 complex intracellularly. These results indicate that TCR beta and gamma chains can be synthesized by one cell line, and that these chains can independently associate with the CD3 complex. However, the results argue against the formation of TCR beta gamma chain complexes in this cell line.
Protective immunogenicity and T lymphocyte specificity of a trivalent hybrid peptide containing NH2-terminal sequences of types 5, 6, and 24 M proteins synthesized in tandem.
Authors: Beachey E H , Seyer J M , Dale J B
Published: June 2004

The protective immunogenicity of a hybrid peptide containing tandem copies of types 5, 6, and 24 M protein epitopes was investigated. An NH2-terminal peptide of type 24 M protein was chemically synthesized and then extended to include NH2-terminal peptides of types 6 and 5 M proteins yielding a 34-residue hybrid peptide containing a cysteine residue at its COOH-terminus. When conjugated via the cysteine residue to keyhole limpet hemocyanin (KLH), emulsified in CFA, and injected into rabbits, the synthetic hybrid evoked opsonic antibodies against types 5, 6, and 24 streptococci without stimulating tissue crossreactive immunity. The trivalent hybrid also was capable of priming T lymphocytes in vivo that responded to each of the native serotypes of M protein as well as to the synthetic hybrid peptide in vitro. The primed T cells failed to respond to the individual component peptides contained in the hybrid peptide, suggesting that the hybrid peptide confers conformations resembling the presentations of each of the subpeptides in the respective serotypes of M protein. The brisk immune responses to the type 6 peptide contained in the middle of the tandem hybrid indicates that with judicious placement between proline residues, potentially hidden peptides are readily accessible to the immune system. These results suggest that synthetic tandem peptides can be tailored in a fashion in which each of the component sets of protective epitopes can be made optimally immunoaccessible and immunogenic.
On the role of the transmembrane anchor sequence of influenza hemagglutinin in target cell recognition by class I MHC-restricted, hemagglutinin-specific cytolytic T lymphocytes.
Authors: Braciale T J , Braciale V L , Winkler M , Stroynowski I , Hood L , Sambrook J , Gething M J
Published: June 2004

We have examined the requirement for the transmembrane hydrophobic anchor sequence of the influenza hemagglutinin (HA) in the formation of the antigenic moiety on the surface of target cells recognized by class I MHC-restricted murine CTL. For this analysis we have used a line of CV-1 monkey epithelial cells that express the transfected murine H-2Kd gene product as target cells and have used recombinant SV40-based late replacement vectors to achieve expression of genes encoding wild-type and mutant forms of HA. We have found that the majority of Kd-restricted HA-specific CTL clones recognize target cells that express a secreted HA molecule that lacks the transmembrane and cytoplasmic domains of the parent glycoprotein. Several Kd-restricted CTL clones that recognize subtype-specific and crossreactive epitopes on HA fail to recognize the anchor-negative, secreted HA or chimeric HA molecules containing the transmembrane and cytoplasmic domains of unrelated glycoproteins. These CTL clones appear to be directed to antigenic epitopes located within the transmembrane domain of HA, as defined by their capacity to recognize target cells sensitized with a synthetic 23-amino-acid peptide corresponding to sequences within this domain. The implications of these results for class I MHC-restricted CTL recognition are discussed.
Interleukin 4 (B cell stimulatory factor 1) can mediate the induction of lymphokine-activated killer cell activity directed against fresh tumor cells.
Authors: Mulé J J , Smith C A , Rosenberg S A
Published: June 2004

Interleukin 4 (IL-4) expresses multiple biologic activities, including B cell, mast cell, and T cell stimulation. We showed that the incubation of resting splenocytes from C57BL/6 mice solely in purified native or recombinant mouse IL-4 results in the generation of lymphokine-activated killer (LAK) activity directed against fresh, syngeneic sarcoma cells. The precursor activated by IL-4 expresses surface asialo-GM1. In addition, IL-4 is capable of amplifying the splenic LAK activity induced by recombinant IL-2. The generation, by IL-4, of killer cells with broad antitumor reactivity raises the possibility of using IL-4 alone or in combination with IL-2 in the immunotherapy of cancer in animal models.
Induction of c-ets and c-fos gene expression upon antigenic stimulation of a T cell hybridoma with inducible cytolytic capacity.
Authors: Kaufmann Y , Silverman T , Levi B Z , Ozato K
Published: June 2004

Expression of cellular oncogenes was studied in a T cell hybridoma that undergoes cytolytic activation when stimulated by specific antigen or by anti-Thy-1 antibody. The activation occurs without induction of hybridoma proliferation, providing a model to examine oncogene expression during functional differentiation of lymphocytes. We found that c-fos and c-ets-1 mRNAs were transiently induced at high levels in the hybridoma 30 min and 4 h after stimulation, respectively. c-myc and c-ets-2 oncogenes were constitutively expressed in the hybridoma and their mRNA levels were unaffected during 4 h of stimulation, although c-myc expression was reduced in the later stage of stimulation. Inhibitors of T cell activation, cyclosporin A and anti-LFA-1 antibody, blocked the induction of c-fos and c-ets-1 mRNAs without reducing the levels of c-myc and c-ets-2. The results indicate that the functional activation of the CTL hybridoma is associated with induction of c-fos and c-ets-1 genes.