bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cholera toxin as a mucosal adjuvant. Glutaraldehyde treatment dissociates adjuvanticity from toxicity.
Authors: Liang X P , Lamm M E , Nedrud J G 
Published: January 2023

Abstract
Cholera toxin (CT), either mixed with or conjugated to unrelated protein Ag, is known to enhance the intestinal IgA response of rodents toward the unrelated Ag. Although relatively low doses of CT exert this gut mucosal adjuvant effect, the inherent toxicity of CT is a hindrance to its use in humans. Our report demonstrates that CT treated with 20 mM glutaraldehyde retains adjuvant properties but exhibits more than 1000-fold lower toxicity than untreated toxin. Glutaraldehyde was also used in a one-stage conjugation procedure to couple CT covalently to Sendai virus. Again, toxicity was reduced more than 1000-fold. This drop in toxicity is consistent with an observed 100-fold loss in binding capacity of the CT B subunit and a 20- to 50-fold reduction in adenylate cyclase activation by the CT A subunit. Oral administration of this virus-toxoid conjugate resulted in increased gut antiviral IgA titers compared with oral administration of either virus alone or of virus mixed with glutaraldehyde-treated toxin. This marked decrease in toxicity may afford a practical approach for the use of CT as a mucosal adjuvant.
Proteolysis induces increased binding affinity of the monocyte type II FcR for human IgG.
Authors: van de Winkel J G , van Ommen R , Huizinga T W , de Raad M A , Tuijnman W B , Groenen P J , Capel P J , Koene R A , Tax W J 
Published: January 2023

Abstract
Human monocytes express two types of IgG FcR, Fc gamma RI and Fc gamma RII. These can be assayed by using indicator E sensitized by human IgG (EA-human IgG) or mouse IgG1, (EA-mouse IgG1), respectively. On mouse macrophages, Fc gamma RI is sensitive to trypsin, whereas Fc gamma RII is trypsin resistant. We studied the effects of the proteolytic enzymes pronase and trypsin on human monocyte Fc gamma R. Neither enzyme caused a decrease in rosetting mediated by monocyte Fc gamma RI. Human Fc gamma RII is polymorphic, and monocytes interact either strongly or weakly with mouse IgG1. The interaction of low responder monocytes with mouse IgG1 was dramatically increased (to the level exhibited by high responder monocytes) by protease treatment. The effects of proteases on Fc gamma RII were investigated in more detail by using monocytes from which Fc gamma RI was selectively modulated by using immobilized immune complexes. Proteolysis of such modulated monocytes induced an increased interaction with EA-human IgG. Fc gamma RII appears to mediate this interaction. This conclusion is supported by the observation that after proteolysis, the Fc gamma RII-mediated binding of EA-mouse IgG1 becomes susceptible to inhibition by (monomeric) human IgG. To quantify the effect of proteolytic enzymes on Fc gamma RII, we performed binding studies with cell line K562, that expresses only Fc gamma RII. A significant increase in Ka of Fc gamma RII for dimeric human IgG complexes was observed when K562 cells were treated with protease. To elucidate the mechanism of this enhancement of Ka by proteolysis, we performed immunoprecipitation studies. Neither m.w., nor IEF pattern of Fc gamma RII were influenced by proteolysis. Moreover, the expression of Fc gamma RII was not affected by proteolysis as evidenced by immunofluorescence studies and Scatchard analysis, and neither were Fc gamma RI or Fc gamma RIII induced. We conclude that proteolysis increases the affinity of Fc gamma RII for human IgG, and speculate that such a proteolysis-induced change may also occur in vivo, e.g., at inflammatory sites.
Cell-mediated immune responses to vaccine peptides derived from the circumsporozoite protein of Plasmodium falciparum.
Authors: Russo D M , Sundy J S , Young J F , Maguire H C , Weidanz W P 
Published: January 2023

Abstract
T cell epitopes residing within vaccine candidate peptides have been identified by delayed-type hypersensitivity (DTH) responses in mice. The recombinant sporozoite vaccine candidate, R32tet32, contains at least two T epitopes, one located within the repeat region and another in the tet tail. When C57BL/6 (H-2b) and BALB/c (H-2d) mice were sensitized intradermally with R32tet32 or the truncated protein R32LR emulsified in CFA and challenged 5 days later with R32tet32, only H-2b mice recognized a T epitope located within the major repeat sequence (NANP) and encoded by four or less repeats. H-2d mice responded solely to the T epitope located on the tet tail. Ear swelling was maximal at 48 h and revealed a histologic pattern characteristic of DTH. CD4+ T cell lines derived from immunized animals demonstrated the ability to mediate local DTH, proliferate, and secrete lymphokines in response to stimulation with Ag. High dose i.v. administration of R32tet32 in C57BL/6 and BALB/c mice before intradermal sensitization with R32tet32 revealed that DTH responses were suppressed only in BALB/c mice. Further experiments localized the suppressive determinant to the tet tail. Collectively, these data indicate that DTH may prove to be a useful method to characterize the biologic activity of T epitopes, furthermore they suggest that candidate vaccine peptides should be tested for suppressive activity before inclusion in a vaccine.
Characterization of the T cell-mediated cellular cytotoxicity during acute infectious mononucleosis.
Authors: Tomkinson B E , Maziarz R , Sullivan J L 
Published: January 2023

Abstract
Primary infection with EBV during acute infectious mononucleosis (IM) is associated with a cytotoxic response against allogeneic target cells. C depletion with anti-CD3 (OKT3) and anti-CD8 (OKT8) mAb decreased the allogeneic cytolysis of two EBV-infected lymphoblastoid cell lines (LCL) by 96% and 89%, respectively. Complement depletion with the NK cell-specific mAb Leu-11b and NKH-1a resulted in only a slight decrease (less than 35%) in the lysis of these LCL. mAb inhibition studies with OKT3 and OKT8 inhibited the allogeneic lysis of two LCL by 87% and 82%, respectively. The alloreactive cytotoxic response was strongly inhibited by mAb specific for MHC class I determinants (W6/32, 65% inhibition and BBM.1, 58% inhibition). Acute IM lymphocytes lysed the allogeneic EBV-negative cell lines HSB2 (45%) and HTLV-1 T cell lines (16%). NK cell-depleted lymphocytes from an acute IM patient demonstrated preferential lysis of K562 transfected with human HLA-A2 (73%) compared with the K562 transfected control (20%). Cold target competition studies with allogeneic and autologous target and competitor LCL demonstrated no significant competitive inhibition between allogeneic and autologous cells. We interpret these results as evidence that 1) the acute IM-alloreactive cytotoxic response is mediated primarily by CTL; 2) these alloreactive CTL lyse allogeneic target cells irrespective of EBV antigenic expression; 3) MHC class I expression is sufficient for allogeneic recognition and lysis of target cells; 4) distinct effector CTL populations mediate lysis of autologous and allogeneic target cells; and 5) during acute IM, EBV infection results in the induction of both virus-specific and alloreactive CTL populations.
Absence of Ig V region gene somatic hypermutation in advanced Burkitt's lymphoma.
Authors: Carroll W L , Yu M , Link M P , Korsmeyer S J 
Published: January 2023

Abstract
Somatic hypermutation of rearranged Ig V region gene plays a major role in generating antibody diversity. Recently, V mutation has been established as a major mechanism of tumor escape from anti-Id immunotherapy. We cloned and sequenced the expressed Ig H and L chain V regions from a case of B acute lymphoblastic leukemia in order to evaluate B cell stages associated with V region mutation, and to determine which tumors would be better suited to Id directed immunotherapy. A consensus VH and V lambda sequence representing tumor at diagnosis was obtained by conventional cDNA cloning in lambda gt10 from a heterohybridoma. Primers which flanked both V regions were used in a modified polymerase chain reaction to generate multiple independent sequences from tumor cells harvested at relapse. In order to exclude mutations due to infidelity of the amplification procedure, single cDNA templates of known sequence were also amplified. The polymerase chain reaction proved to be an effective procedure to obtain multiple clones, but replication in M13 was associated with a low rate of base misincorporation. The results indicate that there is no evidence for biologically significant ongoing mutation in this t(8;14) B cell tumor when comparing sequences at diagnosis and relapse. Thus, V somatic mutation may be restricted to a discrete B cell stage whose malignant counterpart is follicular lymphoma.
IL-2 receptor (Tac antigen) protein expression is down-regulated by the 5'-untranslated region of the mRNA.
Authors: Weinberg A D , Swain S L 
Published: January 2023

Abstract
We have investigated the regulatory role of the 5'-untranslated region (5'-UTR) of the IL-2R mRNA. We noticed a region of striking homology (92%) between the human and bovine IL-2R cDNA in a stretch of 26 nucleotides located in the 5'-UTR. Within this 26 nucleotide region is an AUG that is out of frame with the IL-2R coding sequence. The murine IL-2R cDNA has an 11 bp direct repeat in the 5'-UTR that includes an upstream AUG, and this sequence is identical to the translational start site for the murine IL-2R protein. These observations raised the possibility that the two upstream AUG start codons might down regulate translation of the IL-2R by acting as false translational start sites. To investigate the possibility of IL-2R translational control, we examined sucrose gradient polysome profiles from Con A stimulated murine CD4+ splenocytes. The IL-2R mRNA was found in the portion of the gradient where free RNA, mono, and disomes migrate, whereas actively translated mRNA (lymphokines and beta-actin) were found in the portion of the gradient that contained the polysome fractions. This finding was consistent with translational down-regulation of the IL-2R mediated by ribosomal binding to the 5'-UTR start sites. We next examined cells transfected with the IL-2R cDNA that had the 5'-UTR deleted and compared protein expression to cells transfected with the full length construct. Flow microfluorometry analysis of cell surface IL-2R expression, showed that a clone transfected with the 5'-UTR deletion expressed five- to six-fold more IL-2R than a clone transfected with the full-length construct, even though both clones produced equivalent IL-2R mRNA levels. In clones transfected with the full length construct, the IL-2R mRNA associated with a reduced number of ribosomes compared to the mRNA in the deleted construct clones. These results indicate that sequences in the 5'-UTR of IL-2R mRNA lead to a decrease in the amount of ribosomes bound per IL-2R RNA molecule, and suggest that the level of IL-2R expression can thus be translationally down-regulated. This is the first growth factor receptor shown to be posttranscriptionally controlled at the translational level, and these findings have important implications for IL-2R synthesis and cell surface expression of this immunologically active cell surface receptor.
Altered thymocyte development resulting from expressing a deleting ligand on selecting thymic epithelium.
Authors: Carlow D A , Teh S J , Teh H S 
Published: January 2023

Abstract
The maturation of CD4+8- and CD4-8+ thymocytes from CD4+8+ thymocytes is dependent on the mandatory interaction of their alpha beta TCR with selecting ligands expressed on thymic epithelial cells (TE). This is referred to as positive selection. The deletion of CD4+8+ thymocytes that express autospecific TCR (negative selection) is mediated primarily by bone marrow-derived cells. Previous studies have shown that TE is relatively ineffective in mediating the deletion of CD4+8- thymocytes expressing autospecific TCR but TE can render them anergic, i.e., nonresponsive, to the self Ag. The mechanism by which anergy is induced in these cells is unknown. In this study, we used thymocytes expressing a transgenic TCR specific for the male Ag presented by H-2Db class I MHC molecules to examine how expression of the deleting ligand by TE affects thymocyte development and phenotype. The development of female TCR-transgenic thymocytes was examined in irradiated male hosts or in female hosts that had received male fetal thymic epithelial implants. It was observed that the development of transgenic-TCR+ thymocytes was affected in mice with male TE. CD4+8+ thymocytes with reduced CD8 expression and markedly enhanced transgenic TCR expression accumulated in mice with male TE. Development of CD4-8+ thymocytes was also affected in these mice in that fewer were present and they expressed an intermediate CD8 coreceptor level. These CD4-8+ thymocytes expressed a high level of the transgenic TCR, retained the ability to respond to anti-TCR antibodies, but were nonresponsive to male APC. However, the maturation of CD4+8- thymocytes, which are also derived from CD4+8+ precursor cells, was relatively unaffected. In an in vitro assay for assessing negative selection, male TE failed to delete CD4+8+ thymocytes expressing the transgenic TCR under conditions where they were efficiently deleted by male dendritic cells. Collectively these results support the conclusion that male TE was inefficient in mediating deletion. Furthermore, expression of the deleting ligand on thymic epithelium interferes with the maturation of functional male-specific T cells and results in the accumulation of CD4+8+ and CD4-8+ thymocytes expressing a lower level of the CD8 coreceptor but a high level of the transgenic TCR.
Role of endogenous peptides in murine allogenic cytotoxic T cell responses assessed using transfectants of the antigen-processing mutant 174xCEM.T2.
Authors: Crumpacker D B , Alexander J , Cresswell P , Engelhard V H 
Published: January 2023

Abstract
One model to explain the high frequency of alloreactive T cells proposes that allogeneic MHC molecules are recognized together with host cell-derived peptides. A model system was developed to investigate the relevance of this mechanism by expression of H-2Dd or H-2Ld in 174xCEM.T2 (T2) cells. This human cell line contains a mutation in its Ag-processing pathway that should restrict the association of endogenous peptides with cell surface class I molecules. CTL generated by stimulating C57BL/6 (H-2b) responder cells with H-2Dd or H-2Ld transfectants of the human B cell line C1R or the murine T cell lymphoma EL4 were assayed for their ability to recognize alloantigenic determinants on these transfectants. The major fraction of the H-2Dd-specific allogeneic CTL response, generated in a MLC or under clonal limiting dilution conditions, was composed of T cells that recognized H-2Dd expressed on C1R or EL4 cells, but failed to recognize this molecule on T2 cells. Clonal analysis indicated that approximately one-third of these CTL recognized determinants that were unique to H-2Dd expressed on C1R stimulator cells whereas the remainder recognized determinants that were also found on EL4 transfectants. Less than 10% of H-2Dd-reactive CTL recognized the T2 transfectant, and these clones also killed C1R-Dd and EL4-Dd. This result suggests that the great majority of H-2Dd-specific alloreactive CTL recognize determinants that are formed by a complex of H-2Dd with endogenous peptides that are absent or significantly reduced in T2 cells. Based on recognition of human or murine transfectants, these CTL exhibit some level of specificity for the structure or composition of the bound peptides. Examination of allogeneic CTL specific for H-2Ld revealed populations similar to those described for H-2Dd. In addition, a major new population was present that recognized determinants shared between C1R-Ld and T2-Ld but not present on EL4-Ld. These results are consistent with the idea that the alloreactive response to H-2Ld is also largely dependent on the presence of bound peptide. However, they also may indicate that the H-2Ld molecule expressed on T2 cells is occupied by one or more peptides that are shared with other human, but not murine, cells. The significance of these results to current models of alloreactivity is discussed.
IL-10 inhibits mitogen-induced T cell proliferation by selectively inhibiting macrophage costimulatory function.
Authors: Ding L , Shevach E M 
Published: January 2023

Abstract
IL-10, a newly designated cytokine primarily produced by the Th2 subset of CD4+ T lymphocytes and Ly-1+ B lymphocytes, has recently been hypothesized to inhibit cytokine production by Th1 T cell clones by blocking accessory cell- (AC) dependent costimulatory function. To evaluate the effect of IL-10 on Con A-induced proliferative responses of resting murine T cells, purified T cells were cultured with different types of AC. The addition of IL-10 produced a 70 to 90% inhibition of resting T lymphocyte proliferation when purified populations of macrophages were used as AC, but had no effect on the AC function of T-depleted spleen cells, activated B cells, dendritic cells, or L cells. The inhibitory effects of IL-10 were inversely related to the concentration of mitogen and could be reversed by the addition of the neutralizing anti-IL-10 mAb, SXC1. The inhibition of macrophage AC function was not related to the induction of a suppressor cytokine as stimulation by mixtures of macrophages and limiting numbers of dendritic cells was not inhibited. The decrease in proliferative responses was primarily secondary to inhibition of IL-2 production although the failure of exogenous IL-2 to completely reconstitute the response suggested that IL-10 may also exert inhibitory effects on the induction of expression of a functional IL-2R. These results are most consistent with a model in which IL-10 inhibits the induction of expression on macrophages of a critical costimulatory molecule that may be constitutively expressed on other types of AC.
Enhanced expression of the complement-regulatory factor C8 binding protein (C8bp) on U937 cells after stimulation with IL-1 beta, endotoxin, IFN-gamma, or phorbol ester.
Authors: Schieren G , Janssen O , Hänsch G M 
Published: January 2023

Abstract
C8 binding protein (C8bp) is a 65-kDa membrane glycoprotein that inhibits complement-mediated lysis by homologous C5b-9. C8bp was first identified on human erythrocytes, but could also be detected on peripheral blood cells, platelets, glomerular cells and synovial fibroblasts. Lack of C8bp as seen in patients with paroxysmal nocturnal hemoglobinuria type III results in enhanced susceptibility of the cells toward C5b-9. We studied C8bp expression on the promonocytic cell line U937. In addition to the membrane-bound C8bp, a cytoplasmic form of C8bp could also be identified by immunofluorescence, blotting, and precipitation. Stimulation of the cells with IL-1 beta, endotoxin, IFN-gamma, or phorbol ester increased C8bp surface expression. Because cycloheximide did not inhibit enhanced surface expression, it was most probably mobilized from cytoplasmic reservoirs. Thus, resistance of nuclear cells to complement attack seems to be based on two events: 1) the removal of the C5b-9 complex from the membrane; and 2) expression of regulatory surface proteins such as C8bp, which inhibit C5b-9-mediated lysis. We propose that the C8bp mobilization by cytokines might provide an additional protection against complement attack by its known interference with the C5b-9 assembly.
Role of Fc gamma RII in platelet activation by monoclonal antibodies.
Authors: Slupsky J R , Cawley J C , Griffith L S , Shaw A R , Zuzel M 
Published: January 2023

Abstract
mAb are being widely used to probe the function of cell-surface proteins. The cell stimulation that may be produced is often dependent on mAb interaction with both the target Ag and FcR. However, it remains unclear whether these interactions take place on the same cell or between adjacent cells and whether the FcR plays an anchoring or signaling role. Using the model of platelet activation, we demonstrate that two different Fc-dependent mAb, LeoA1 and ALB6, both activate the cell by forming intercellular links between Ag on one cell and FcR on the opposing platelet. We also show that the mAb differ with respect to the relative roles of target Ag vs FcR in provision of the stimulation signal. Thus Fc gamma RII played a mainly anchorage role in LeoA1 stimulation, whereas its role in ALB6 stimulation was mainly signaling. Therefore the precise contribution of each of these roles to the overall effect of a stimulatory antibody should be determined before the antibody is used as a specific functional probe.
Extracellular signal-regulated kinases in T cells. Anti-CD3 and 4 beta-phorbol 12-myristate 13-acetate-induced phosphorylation and activation.
Authors: Whitehurst C E , Boulton T G , Cobb M H , Geppert T D 
Published: January 2023

Abstract
Extracellular signal-regulated kinases (ERK) 1 and 2 are growth factor- and cytokine-sensitive serine/threonine kinases that are known to phosphorylate microtubule-associated protein 2 and myelin basic protein. The current studies examined whether ERK1 and/or ERK2 was present in T cells and whether they were phosphorylated and activated as a consequence of T cell activation. The data demonstrated that both ERK1 and ERK2 were present in Jurkat cells and peripheral blood T cells. In T cells, ERK2 was more prevalent than ERK1. The concentrations of ERK1 and ERK2 were not altered by stimulating the cells for 16 h with immobilized anti-CD3 mAb or anti-CD3 mAb and phorbol myristate acetate. mAb to CD3 and phorbol myristate acetate stimulated an increase in ERK1 and ERK2 MBP kinase activity. Anti-CD3 mAb triggered an increase their phosphate content which was detectable at 2 min but reached a maximum at 5 min. A portion of the increase in phosphate was caused by an increase in phosphotyrosine. We also examined the rate of ERK2 degradation. ERK2 was stable for up to 36 h, and its degradation was unaffected by the activation state of the cells. The data demonstrate that ERK1 and ERK2 are part of an anti-CD3 mAb-stimulated signal transduction cascade that is downstream of protein kinase C and, therefore, suggest that these kinases play an important role in T cell activation.
Complete complementary DNA sequence of the third component of complement of lamprey. Implication for the evolution of thioester containing proteins.
Authors: Nonaka M , Takahashi M 
Published: January 2023

Abstract
Lamprey liver mRNA sequences were amplified by reverse transcriptase-polymerase chain reaction using primers synthesized according to the amino acid sequences at the thioester region common to the mammalian C3, C4, and alpha 2-macroglobulin (alpha 2M). Two different cDNA species were identified that showed a close similarity to the mammalian C3 or alpha 2M sequences, respectively. Using the C3-like sequence as a probe, two overlapping cDNA clones were isolated from the lambda ZAP library, which together covered the entire region encoding the putative lamprey pro-C3. The deduced amino acid sequence of the putative lamprey pro-C3 contained 1660 amino acids and showed 31%, 22%, 23%, and 16% amino acid sequence identity with mouse C3, C4, C5, and human alpha 2M, respectively. The distributions of cysteine residues were completely identical between the mouse C3 and the putative lamprey C3 except that the lamprey sequence had two additional cysteine residues in the alpha-chain. The possible beta-alpha and alpha-gamma processing sites were found at exactly the same positions as in mammalian C4. These results suggest that the putative lamprey C3 retains a close similarity to the common ancestor of the mammalian C3 and C4, which appeared to have had a three-subunit chain structure.