bluuebunny/crossref_metadata_2025_split huggingface dataset:
Membrane Ig cross-linking regulates phosphatidylinositol 3-kinase in B lymphocytes.
Authors: Gold M R , Chan V W , Turck C W , DeFranco A L 
Published: December 2022

Abstract
Cross-linking of the B cell AgR results in activation of mature B cells and tolerization of immature B cells. The initial signaling events stimulated by membrane immunoglobulin (mIg) cross-linking are tyrosine phosphorylation of a number of proteins. Among the targets of mIg-induced tyrosine phosphorylation are the tyrosine kinases encoded by the lyn, blk, fyn, and syk genes, the mIg-associated proteins MB-1 and Ig-beta, phospholipase C-gamma 1 and -gamma 2, as well as many unidentified proteins. In this report we show that mIg cross-linking also regulates phosphatidylinositol 3-kinase (PtdIns 3-kinase), an enzyme that phosphorylates inositol phospholipids and plays a key role in mediating the effects of tyrosine kinases on growth control in fibroblasts. Cross-linking mIg on B lymphocytes greatly increased the amount of PtdIns 3-kinase activity which could be immunoprecipitated with anti-phosphotyrosine (anti-tyr(P) antibodies. This response was observed after mIg cross-linking in mIgM- and mIgG-bearing B cell lines and after cross-linking either mIgM or mIgD in murine splenic B cells. Thus, regulation of PtdIns 3-kinase is a common feature of signaling by several different isotypes of mIg. This response was rapid and peaked 2 to 3 min after the addition of anti-Ig antibodies. The anti-Ig-stimulated increase in PtdIns 3-kinase activity associated with anti-Tyr(P) immunoprecipitates could reflect increased tyrosine phosphorylation of PtdIns 3-kinase, increased activity of the enzyme, or both. In favor of the first possibility, the tyrosine kinase inhibitor herbimycin A blocked the increase in ant-Tyr(P)-immunoprecipitated PtdIns 3-kinase activity as well as the anti-Ig-induced tyrosine phosphorylation. Moreover, this response was not secondary to phospholipase C activation but rather seemed to be a direct consequence of mIg-induced tyrosine phosphorylation. Activation of the phosphoinositide pathway by a transfected M1 muscarinic acetylcholine receptor expressed in WEHI-231 B lymphoma cells did not increase the amount of PtdIns 3-kinase activity which could be precipitated with anti-Tyr(P) antibodies. Similarly, inhibition of the phosphoinositide pathway did not abrogate the ability of mIg cross-linking to stimulate this response. Thus, mIg-induced tyrosine phosphorylation regulates PtdIns 3-kinase, an important mediator of growth control in fibroblasts and potentially an important regulatory component in B cells as well.
Unassembled HLA-DR beta monomers are degraded rapidly by a nonlysosomal mechanism.
Authors: Cotner T 
Published: December 2022

Abstract
We previously observed that in a mutant B lymphoblastoid cell line which has a homozygous HLA-DR alpha deletion, DR beta-chains appeared to be unstable. In the present study, we have studied the pathway that leads to degradation of unassembled DR beta-chains. Unassembled DR beta-chains are degraded rapidly in the DR alpha deletion mutant cells, compared with the assembled DR heterodimers present in non-mutant cells. Accelerated DR beta turnover in 9.22.3 cells is specific; class I molecules in these DR alpha-deficient cells turned over slowly. DR beta-chains assemble with Ii in the DR alpha deficient cell line, but this did not protect DR beta-chains from degradation. The maturation of unassembled beta-chains is arrested before their reaching the medial Golgi compartment, and this degradation proceeds by a nonlysosomal, nonendosomal pathway. Degradation of DR beta-chains is blocked when cells are cultured at 16 degrees C, a temperature known to prevent vesicular transport between the endoplasmic reticulum (ER) and the Golgi apparatus. Degradation is also inhibited by carbonyl cyanide m-chlorophenylhydrazone, a drug that is also known to inhibit protein transport from the ER. The results, taken together, suggest that degradation of unassembled DR beta-chains occurs by a nonlysosomal, nonendosomal pathway which involves transport of DR beta-chains out of the ER.
MHC-unrestricted cytotoxic and proliferative responses of two distinct human gamma/delta T cell subsets to Daudi cells.
Authors: Fisch P , Oettel K , Fudim N , Surfus J E , Malkovsky M , Sondel P M 
Published: December 2022

Abstract
Human V gamma 9/V delta 2 T cells, the major subset of gamma/delta T cells in peripheral blood of adults, mediate proliferative and cytotoxic responses to Daudi Burkitt's lymphoma cells without previous in vitro exposure to Daudi. Our experiments show that some gamma/delta T cells coexpressing V gamma 9 and V delta 1 genes also react to Daudi cells in cytotoxic and proliferative assays. Expression of V gamma 9 is not sufficient for the recognition of Daudi cells because most gamma/delta T cells expressing V delta 1 paired with V gamma 9 or other V gamma genes neither kill Daudi cells nor proliferate to Daudi. V gamma 9/V delta 2 T cells do not proliferate to other cell lines such as K562 or Molt4 that are sensitive to MHC-unrestricted cytolysis by NK cells and by most IL-2-activated gamma/delta T cell clones. Cold target inhibition assays demonstrate that Daudi cells are stronger inhibitors than K562 and Molt4 of MHC-unrestricted lysis by V gamma 9/V delta 2 clones. However, cold Daudi cells are relatively weaker inhibitors of MHC-unrestricted lysis by NK cell clones, most gamma/delta T cell clones expressing V delta 1 and alpha/beta T cell clones. Thus, recognition by V gamma 9/V delta 2 T cells and certain V gamma 9/V delta 1 T cells of Daudi appears to involve a specific triggering pathway that is distinct from recognition by these gamma/delta T cells of Molt4, K562, and other target cells. NK cell clones and most other gamma/delta and alpha/beta T cell clones derived from the same normal volunteer blood donors do not show this specific interaction with Daudi cells. These data show that distinct subsets of human gamma/delta T cells recognize Daudi cells and support the idea that the gamma/delta TCR may be directly involved.
Regulation of adhesion molecule expression by CD8 T cells in vivo. I. Differential regulation of gp90MEL-14 (LECAM-1), Pgp-1, LFA-1, and VLA-4 alpha during the differentiation of cytotoxic T lymphocytes induced by allografts.
Authors: Mobley J L , Dailey M O 
Published: December 2022

Abstract
A variety of adhesion molecules regulate the traffic and tissue localization of lymphocytes in vivo by mediating their binding to vascular endothelial cells. The homing receptor gp90MEL-14 (gp90), also known as LECAM-1 or L-selectin, mediates the adhesion of lymphocytes to specialized high endothelial venules in lymph nodes (LN) and is the primary molecule regulating lymphocyte recirculation and homing to LN, whereas other adhesion molecules have a major role in the localization of lymphocytes in inflammatory sites. We used four-color flow cytometric analysis to examine the regulation of adhesion receptor expression on LN CD8 T cells responding to skin allografts in vivo. In normal mice, greater than 95% of LN CD8 T cells are gp90+, being either gp90+Pgp1- (Population (Pop.) 1 or gp90+Pgp-1+ (Pop.2). Allografting induces the down-regulation of gp90 and up-regulation of Pgp-1 on a subset of cells, resulting in the appearance of CD8+gp90-Pgp-1hi (Pop. 3) cells. Pop. 3 cells also express high levels of LFA-1, ICAM-1, and ICAM-2, and a subset of them are VLA-4 alpha-positive. Purified Pop. 3 cells have potent cytolytic activity directed against donor alloantigen, whereas no such activity is present in Pop. 1 or 2 cells. Correlating with this is the high granzyme activity in Pop. 3 cells. In addition, Pop. 3 lymphocytes, but not Pop. 1 or 2, secrete a large amount of IFN-gamma in response to Ag. Finally, the CD8 T cells that infiltrate sponge matrix allografts are markedly enriched for the Pop. 3 subset. These results show that, during the immune response to alloantigen in vivo, a small subset of CD8 T cells down-regulates the LN homing receptor while increasing the expression of other adhesion molecules, as they differentiate into highly active cytolytic T lymphocytes. Thus, the differential regulation of LN homing receptors and receptors for peripheral vascular endothelium provides a mechanism that would redirect the traffic of activated effector cells away from lymphoid tissue and to sites of Ag deposition, where they would participate in the inflammatory response.
In vitro and in vivo activation of murine gamma/delta T cells induces the expression of IgA, IgM, and IgG Fc receptors.
Authors: Sandor M , Houlden B , Bluestone J , Hedrick S M , Weinstock J , Lynch R G 
Published: December 2022

Abstract
The present studies examined resting and activated murine gamma/delta T lymphocytes, in vitro and in vivo, for surface expression of FcR. Polyclonal gamma/delta TCR+ lymphocytes selectively grown from the spleen and intestine of normal mice did not express FcR when the cells were in a resting state, but when cells were activated with anti-CD3 antibody virtually all of the splenic gamma/delta lymphocytes and a large subpopulation of the intestinal gamma/delta lymphocytes expressed IgA and IgM FcR. This was confirmed by using transgenic mice. Resting gamma/delta TCR+ lymphocytes from the spleen, thymus, lymph node, and blood of gamma/delta TCR transgenic mice did not express FcR for any of the five major classes of Ig H chains. Activation of the gamma/delta TCR+ cells via the CD3/TCR complex induced high levels of IgM and IgA FcR and low levels of IgG FcR. Finally, in hepatic granulomas of schistosome-infected mice, activated gamma/delta TCR+ cells are present and express high levels of IgA and IgM FcR and low levels of IgG FcR. These investigations establish that transition of gamma/delta TCR+ lymphocytes from a resting to an activated state (triggered via the T3Ti TCR complex) is accompanied by the induction of surface membrane receptors specific for Ig H chain isotypes. The activation-linked expression of FcR on gamma/delta TCR+ lymphocytes provides potential mechanisms for coupling the functional activities of gamma/delta T lymphocytes with immune mechanisms that involve Ig molecules, such as antibody-dependent cellular cytotoxicity.
Human T cell responses to purified pollen allergens of the grass, Lolium perenne. Analysis of relationship between structural homology and T cell recognition.
Authors: Baskar S , Parronchi P , Mohapatra S , Romagnani S , Ansari A A 
Published: December 2022

Abstract
The in vitro proliferative response to purified allergens of the grass, Lolium perenne pollens was studied using PBMC from individuals allergic to grass pollens and Ag-specific T cell lines and T cell clones derived from them. The PBMC from all 10 subjects studied showed a strong response to Lol p I and most of them (8 of 10) also responded to Lol p III. Although Lol p II induced a moderate response in 4 of 10 individuals, it did not induce any response in others at all the Ag concentrations tested. However, one of the subjects (JH) responded to, besides Lol p I, both Lol p II and Lol p III equally well. Analysis of Ag-specific T cell lines and clones derived from three individuals showed varied pattern of reactivity to the Lol p allergens. Some of the Lol p III-specific T cell lines and clones were also stimulated by Lol p I and similarly, some of the Lol p I-specific T cell clones (derived from four other subjects) were stimulated by Lol p III; thus showing a two-way cross-reactivity between those T cells. In both cases, the cross-reactivity to Lol p II, when observed, was lower than that seen with Lol p I and Lol p III. Comparison of amino acid sequences of the three Lol p proteins revealed a significant level of structural similarity among them, including several segments of identical sequences. Although one of the synthetic peptides of Lol p III sharing appreciable sequence homology with other proteins stimulated PBMC from two subjects, three other peptides did not. Nevertheless, these studies indicated the possible existence of cross-reactive T cell epitope(s) among the grass pollen allergens. Based on these results, the relationship between amino acid sequence homology among the Lol p proteins and their recognition by T cells is discussed.
A comparative study of IL-12 (cytotoxic lymphocyte maturation factor)-, IL-2-, and IL-7-induced effects on immunomagnetically purified CD56+ NK cells.
Authors: Naume B , Gately M , Espevik T 
Published: December 2022

Abstract
IL-12, or cytotoxic lymphocyte maturation factor, is a recently cloned cytokine shown to influence lymphokine-activated killer cells activity in heterogeneous lymphocyte populations, proliferative activity as a costimulus in PBMC/PBL populations and IFN-gamma production in PBL. We have investigated the effects of IL-12 on immunomagnetically highly purified CD56+ lymphocytes, and compared the effects with those of IL-7 and IL-2. Our results show that IL-12 directly generated high lymphokine-activated killer cell activity in CD56+ NK cells, without the need for accessory cells. The IL-12-induced lymphokine-activated killer cell activity reached 50% of what was obtained with IL-2. In contrast, only low proliferative activity was induced by IL-12, as 10% of the IL-2-induced- and approximately 50% of the IL-7-induced proliferative activity was detected with IL-12. The CD56+ cells expressed high levels of IL-2R alpha and 75-kDa TNFR in response to IL-12, comparable to what was registered with IL-2 and IL-7. Furthermore, an extensive up-regulation of the CD56 Ag, to the level obtained with IL-2, was detected in the CD56+ NK cells in the presence of IL-12. Stimulation with IL-7 resulted in a more limited CD56 up-regulation in the CD56+ NK cells. Low concentrations of TNF-alpha were produced in response to both IL-12 and IL-7, with little or no TNF-beta production. Time course of the IL-2-induced TNF production revealed an initial TNF-alpha production, whereas significant levels of TNF-beta were detected after 72 h. The effects of both IL-12 and IL-7 on the CD56+ NK cells were inhibited by an anti-TNF-alpha mAb. Thus, IL-12 can directly influence NK cell activities in purified CD56+ cells, and endogenously produced TNF-alpha is involved in mediating the effects of both IL-12 and IL-7.
MHC interaction and T cell recognition of carbohydrates and glycopeptides.
Authors: Ishioka G Y , Lamont A G , Thomson D , Bulbow N , Gaeta F C , Sette A , Grey H M 
Published: December 2022

Abstract
The T cell independence of complex polysaccharide Ag has suggested the possibility that carbohydrates may be incapable of T cell recognition because of a failure to interact with MHC restriction elements and/or a failure of MHC/carbohydrate complexes to interact with and be recognized by Ag-specific TCR. We have used two approaches to obtain information about T cell recognition of carbohydrate. First, we have determined the capacity of a series of oligosaccharides and glycolipids to bind a murine class II MHC molecule, IAd. No significant binding was observed with the 26 compounds tested, but the limitation to these studies was that there was a relatively limited collection of synthetic carbohydrate and glycolipid structures of limited complexity available for analysis. The second approach involved the study of the effect of glycosylation of a known peptide T cell epitope (OVA 323-339) on MHC binding of the peptide and on T cell recognition. Three patterns of effects were observed: 1) no effect on either binding or T cell recognition. This pattern was observed when the carbohydrate was located at residues removed from the core MHC-binding region. When the carbohydrate was located within the core MHC-binding regions, either 2) glycosylation destroyed both MHC binding and T cell recognition; or 3) glycosylation did not ablate MHC binding or T cell recognition. In this latter instance, there was evidence to indicate that the carbohydrate moiety was an important part of the antigenic determinant recognized by T cells.
Expression and regulation of a recurrent anti-erythrocyte autoantibody idiotype in spleen cells from neonatal and adult BALB/c mice.
Authors: Miller R D , Caulfield M J , Calkins C E 
Published: December 2022

Abstract
BALB/c spleen cells depleted of CD8+ T cells generate an autoantibody response to mouse RBC (MRBC) when cultured 5 days in the presence of syngeneic RBC. More than 80% of the cells secreting anti-MRBC antibody are blocked by an antiidiotypic mAb that recognizes the G8 Id. This G8 Id was originally identified in an autoimmune NZB mouse derived anti-MRBC mAb and later characterized as a dominant Id in NZB anti-MRBC autoantibodies. Furthermore, the CD8+ regulatory T cells that control this autoimmune response in BALB/c mice are specifically eliminated by cytotoxic treatment with the G8 mAb + C, suggesting that the regulatory cells recognize the G8 Id. Spleen cells from neonatal BALB/c mice, which lack those regulatory cells can generate an in vitro antibody response to MRBC without depletion of CD8+ cells. More than 80% of these AFC were also found to express the G8 Id. We propose that Id determinants on autoantibodies that are produced neonatally induce Id-specific regulatory cells that maintain peripheral tolerance to self-RBC throughout the life of normal animals.
Protease composition of exocytosed human skin mast cell protease-proteoglycan complexes. Tryptase resides in a complex distinct from chymase and carboxypeptidase.
Authors: Goldstein S M , Leong J , Schwartz L B , Cooke D 
Published: December 2022

Abstract
We characterized the release and the protease composition of high m.w. complexes released from dispersed human skin mast cells, under conditions that did not disrupt the binding of proteases to proteoglycan. The net percent release ratio of tryptase to histamine, after anti-IgE and calcium ionophore A23187 stimulation was higher than those for chymase or carboxypeptidase. This was explained by the greater cell association of carboxypeptidase and chymase, compared with tryptase, after mast cell degranulation and/or differential cosedimentation of the proteases with mast cells, because treatment of activated mast cells with 1 M NaCl increased the release ratios of chymase and carboxypeptidase more than that of tryptase. Tryptase, after release, was stable in 0.12 M NaCl and had a molecular mass of approximately 200 to 250 kDa, suggesting that it was bound to proteoglycan. We demonstrated that complexes containing chymase and carboxypeptidase were separable from tryptase-containing complexes by gel filtration and by affinity chromatography. First, on fast protein liquid chromatography, released tryptase filtered at a molecular mass of approximately 200 to 250 kDa, compared with chymase and carboxypeptidase at 400 to 560 kDa. Second, by using affinity chromatography with immobilized antitryptase mAb in 0.15 M NaCl, carboxypeptidase and chymase activities were recovered primarily in the effluent and washes of an antitryptase antibody affinity column and cofiltered at 400 to 560 kDa. Tryptase was recovered only in the eluate. Finally, by using potato tuber carboxypeptidase inhibitor-Sepharose affinity chromatography, tryptase activity was found primarily in the effluent and washes, filtered at a molecular mass of 200 kDa on fast protein liquid chromatography, and was stable in 0.12 M NaCl buffer at 37 degrees C. Carboxypeptidase and chymase activities were found primarily in the eluate. These findings suggest that tryptase and carboxypeptidase/chymase reside in distinct macromolecular complexes. Separate complexes containing these proteases may help explain previous ultrastructural observations in which the distributions of chymase and tryptase within a single granule did not always coincide.
IFN-gamma enhances expression of formyl peptide receptors and guanine nucleotide-binding proteins by HL-60 granulocytes.
Authors: Klein J B , Scherzer J A , McLeish K R 
Published: December 2022

Abstract
Exposure to IFN-gamma increases the respiratory burst of polymorphonuclear leukocytes stimulated by the chemoattractant FMLP. However, the mechanism by which IFN-gamma alters the response to FMLP is unclear. We addressed the hypothesis that IFN-gamma enhances the response to FMLP by regulating the expression of elements of the formyl peptide receptor transmembrane-signaling pathway. HL-60 granulocytes were used as a model of FMLP transmembrane signaling. Formyl peptide receptor number and affinity were studied in isolated plasma membranes prepared from control HL-60 cells (CM) and cells exposed to IFN-gamma 100 U/ml for 24 h (IFN-M). Formyl peptide receptors were significantly increased on IFN-M compared with CM (1473 +/- 300 vs 3209 +/- 924). FMLP stimulates increased guanine nucleotide-binding protein (G protein) activation in IFN-M as evidenced by enhanced guanosine 5'-[gamma-thio]triphosphate binding and GTPase activity. Gi sub-unit content was increased in IFN-M as measured by pertussis toxin-catalyzed ADP-ribosylation and immunoblotting with antibodies against alpha i2 and alpha i3 G protein subunits. Guanosine 5'-[gamma-thio]triphosphate equilibrium binding demonstrated an increased number of G proteins coupled to formyl peptide receptors on IFN-M. We conclude that IFN-gamma increases expression of both formyl peptide receptors and G proteins coupled to these receptors, thereby enhancing FMLP-stimulated transmembrane signaling. Regulation of transmembrane signaling element expression may be a significant mechanism by which IFN-gamma regulates cellular functions.
A role for protein tyrosine kinase activity in natural cytotoxicity as well as antibody-dependent cellular cytotoxicity. Effects of herbimycin A.
Authors: O'Shea J J , McVicar D W , Kuhns D B , Ortaldo J R 
Published: December 2022

Abstract
NK cells, CD3- large granular lymphocytes, have diverse means by which they lyse targets, including antibody-dependent cellular cytotoxicity. The low affinity receptor for the Fc portion of Ig (Fc gamma RIIIA), like the TCR, is a multimeric receptor complex coupled to a protein tyrosine kinase. In the present study, we observed that inhibition of tyrosine kinase activity by herbimycin A interferes with receptor-mediated phosphorylation of a variety of substrates and mobilization of intracellular calcium. Fc gamma RIIIA induced IL-2R alpha-chain expression was also extremely sensitive to herbimycin A as was antibody-dependent cellular cytotoxicity, in fact more so than receptor-mediated phosphorylation and calcium mobilization. In contrast to Fc gamma RIIIA, the surface molecules and biochemical mechanisms involved in NK cytotoxicity and lymphokine-activated killing are not well characterized. Interestingly, however, herbimycin A also blocks these modes of cytolysis, implicating a role for tyrosine kinase function in these processes. Whether FcR-mediated signaling and receptor-mediated signaling involved in NK activity share specific biochemical intermediates is not known, but the involvement of tyrosine kinase function in the latter means of cytotoxicity may provide novel avenues for understanding the biochemical basis of this perplexing cellular function.