bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lymphokine-activated killer cell activity of CD4-CD8- TCR alpha beta + thymocytes.
Authors: Arase H , Arase-Fukushi N , Good R A , Onoé K 
Published: January 2023

Abstract
Functions of CD4-8-TCR alpha beta+ thymocytes, which are characterized by predominant usage of V beta 8.2 TCR, have remained unclear. In this study, we found that the CD4-8-TCR alpha beta + thymocytes expressed NK1.1 Ag and IL-2R beta-chain but not IL-2R alpha-chain. When the CD4-8- TCR alpha beta + thymocytes were cultured in the presence of IL-2, the CD4-8-TCR alpha beta + thymocytes vigorously proliferated. After 7 days of culture in the presence of 1000 U/ml of IL-2, approximately half of the CD4-8-TCR alpha beta + thymocytes lost NK1.1 Ag. However, the remaining half of the CD4-8-TCR alpha beta + cells showed increasing levels of NK1.1 Ag and acquired killer activity against tumor cells such as YAC-1, P815, and EL-4. These cells also killed syngeneic as well as allogeneic thymocytes. The LAK activity by the NK1.1+ CD4-8-TCR alpha beta + thymocytes was not inhibited by anti-NK1.1, anti-TCR alpha beta, or anti-CD44 mAb but was partially inhibited by anti-LFA-1 mAb. These findings indicate that the CD4-8-TCR alpha beta + thymocyte population can be divided into two population on the basis of NK1.1 expression after culture in the presence of IL-2. The NK1.1 Ag expression on the cultured CD4-8-TCR alpha beta + seems to be correlated to acquisition of LAK activity, although the NK1.1 Ag itself may not be directly involved in the target cell recognition. The present data suggest that the CD4-8- TCR alpha beta + thymocyte population is a functional T cell lineage which may serve as cells of immune defense and/or immune regulation.
Peripheral T cells in mice lacking p56lck do not express significant antiviral effector functions.
Authors: Molina T J , Bachmann M F , Kündig T M , Zinkernagel R M , Mak T W 
Published: January 2023

Abstract
Mutant mice lacking p56lck, the T cell-specific protein tyrosine kinase, have a profound thymic atrophy and possess only an immature thymocyte population. Only 5 to 10% of normal levels of mature T cells (TCR-alpha beta+, CD4+, or CD8+) are present in these mice. These T cells, but also B cells of mutant mice, can be activated by mitogens, and T cells proliferate upon stimulation with IL-2 or mAb against the TCR. Thus, it appears that selected T cells can mature without lck and that they may have circumvented the need for this enzyme. This study evaluated the capacity of these mice to generate antiviral immune responses: 1) mutant mice failed to generate virus-specific CTL after acute infection with lymphocytic choriomeningitis virus (LCMV) or vaccinia virus. 2) LCMV was not cleared from the spleen on day 10 after infection. 3) Infection of LCMV into footpads of mutant mice did not induce a T cell-dependent swelling reaction. 4) Intracerebral inoculation with LCMV did not induce in mutant mice any clinical signs of sickness. 5) Vesicular stomatitis virus (VSV)-primed mutant mice could not eliminate nucleoprotein of VSV recombinant vaccinia virus upon intracerebral infection. 6) VSV infection of mutant mice elicited normal, specific T cell-independent IgM responses, but no significant switch to IgG. These results show that, despite the presence of in vitro activatable CD8+ and CD4+ T cells in the mutant mice, no biologically relevant functions can be detected. Therefore, these data indicate that p56lck is directly or indirectly crucially involved in in vivo Ag-induced T cell responses.
Association of an activation inducible serine kinase activity with CD5.
Authors: Alberola-Ila J , Places L , Lozano F , Vives J 
Published: January 2023

Abstract
We show the association of a protein kinase activity with CD5 immunoprecipitates under different detergent conditions (1% digitonin, 1% Triton X-100). This association can be observed in all CD5+ cell types tested (PBMC, thymocytes, B cells from chronic lymphocytic leukemia, and some lymphoblastoid T cell lines as Jurkat, Molt-4, 8402). Phosphoaminoacid analysis of the in vitro phosphorylated proteins and Western blot analysis of the immunoprecipitates with an antiphosphotyrosine mAb show that, in contrast with other lymphocyte receptors (CD3, CD4, IL-2R), CD5 coimmunoprecipitates a serine kinase activity. Our results show also that preactivation of cells through the CD3/TCR complex induces a rapid (detectable in 1-3 min) and transient (returns to basal levels after 10-15 min) increase in the kinase activity associated with CD5 immunoprecipitates. This CD3-induced increase in CD5-associated kinase activity correlates with an increase in CD5 phosphorylation. Furthermore, activation with soluble anti-CD5 mAb induces also an increase in the kinase activity associated with this receptor. In contrast with the increase observed after activation with CD3, after activation with CD5 the increase in the kinase activity peaks after 10 min and is maintained for 1 h. These different kinetics suggest that there may exist different mechanisms that regulate this phenomenon.
Cell adhesion mediated by CD4 and MHC class II proteins requires active cellular processes.
Authors: Kinch M S , Strominger J L , Doyle C 
Published: January 2023

Abstract
Human CD4 is an accessory molecule found on the cell surface of a subset of T lymphocytes. We have previously shown by infection of simian fibroblasts with an SV40-CD4 recombinant virus that CD4 acts as an adhesion molecule by binding to human MHC class II Ag expressed on the surface of human B lymphocytes. This report confirms that human B lymphoblastoid cell lines expressing class II molecules at the cell surface can bind to Chinese hamster ovary cells that have been stably transfected with human CD4. This cellular adhesion is a late event, which is first detected after 2 h, but remains stable for up to 16 h. The association between CD4 and class II is energy dependent, as it is detected at 37 degrees C, but not at 4 degrees C or if either cell type is fixed with paraformaldehyde. ATP is required for the establishment and maintenance of stable CD4/class II-mediated cell conjugates. Cytoskeletal interactions also regulate CD4/class II adhesion as treatment with the microtubule and microfilament inhibitors colchicine, cytochalasin-D, and nocodazole rapidly dissociates even preformed cell conjugates. Our observations also indicate that the Ag-independent engagement of class II by CD4 induces homotypic clustering of human B cells. This effect is blocked by reagents directed against lymphocyte function-associated Ag-1 and may result from the induction of a high affinity phenotype of lymphocyte function-associated Ag-1 induced by class II signaling. Finally, we discuss the implications of CD4/class II-mediated adhesion and the role of CD4 in the regulation of T cell adhesion.
Normal sequence of phenotypic transitions in one cohort of 5-bromo-2'-deoxyuridine-pulse-labeled thymocytes. Correlation with T cell receptor expression.
Authors: Lucas B , Vasseur F , Penit C 
Published: January 2023

Abstract
"In vivo" kinetics of T cell differentiation and TCR expression in the normal murine thymus were re-evaluated using a new technique for simultaneous detection of bromodeoxyuridine and two surface markers. The transition from CD4-8- precursors to CD4+8+ immature cells was directly observed during cell proliferation, and shown to proceed through transitory intermediates expressing no or low amounts of CD4. CD3-TCR expression also started during this transition and resulted in the production of a majority of TCRlo cells but also of a significant number (1 to 2 x 10(6) of TCRhi immature (heat-stable Ag+) thymocytes. After cessation of proliferation, the maturational transition from CD4+8+ to CD4+8- and CD4-8+ (in this order) was restricted to TCRhi cells produced during CD4+8+ cell generation. The acquisition of the single positive phenotype preceded HSA down-regulation, suggesting that maturation of TCRhi thymocytes proceeds in two separate steps. The major TCRloCD4+8+ subset appeared a dead end subset and showed no up-regulation of TCR expression at any time.
Transforming growth factor-beta 1 is required for secretion of IgG of all subclasses by LPS-activated murine B cells in vitro.
Authors: Snapper C M , Waegell W , Beernink H , Dasch J R 
Published: January 2023

Abstract
Addition of transforming growth factor-beta 1 (TGF-beta 1) to in vitro cultures of murine B cells activated with bacterial LPS selectively stimulates IgG2b and IgA class switching and decreases cellular proliferation. To assess a possible role for endogenous TGF-beta in modulating the Ig isotypes produced by LPS-activated cells, we utilized a neutralizing anti-TGF-beta mAb to abrogate endogenous TGF-beta activity. Anti-TGF-beta antibody, over a range of relatively low cell densities, strikingly inhibited both IgG3 and IgG2b production in response to LPS, with little or no change in the concentrations of secreted IgM. This effect of anti-TGF-beta antibody was specific, since it did not occur with an isotype-matched control mAb and was completely reversed with exogenous TGF-beta 1. Optimal IgG3 secretion occurred at concentrations of TGF-beta that were approximately eightfold lower than that necessary for maximal synthesis of IgG2b. Neutralization of endogenous TGF-beta in LPS-activated cultures was associated with an approximately twofold increase in proliferation and viable cell yields, a modest decrease in the percentage of membrane (m)IgG2b+ cells, and a modest increase in the percentage of mIgG3+ cells. This latter finding indicated that TGF-beta was not required for IgG3 class switching, but for maturation of mIgG3+ cells into Ig secretors. Highly purified B cells, obtained by electronic cell sorting, released active TGF-beta in response to LPS and showed a similar marked reduction in LPS-mediated IgG3 and IgG2b secretion in the presence of anti-TGF-beta antibody. Abrogation of endogenous TGF-beta activity in LPS-activated cultures also resulted in a striking reduction in IFN-gamma-mediated IgG2a production, and a more modest decrease in the synthesis of IgG1 and IgE in the presence of IL-4. These data indicate that relatively low concentrations of TGF-beta are essential for stimulating optimal IgG secretion by LPS-activated B cells, in an Ig isotype-nonspecific manner, and may regulate these responses in an autocrine fashion.
Protective immunity in baboons vaccinated with a recombinant antigen or radiation-attenuated cercariae of Schistosoma mansoni is antibody-dependent.
Authors: Soisson L A , Reid G D , Farah I O , Nyindo M , Strand M 
Published: January 2023

Abstract
Mice vaccinated with radiation-attenuated cercariae of Schistosoma mansoni exhibit high levels of resistance to challenge infection. We have previously shown that sera from these mice recognize polypeptides that are expressed on the surface of newly transformed schistosomula. We have cloned and sequenced a cDNA that encodes a 62-kDa portion of one of these polypeptides. Vaccination of mice with this 62-kDa polypeptide (designated rlrV-5) elicits high antibody titers and significant resistance to challenge infection. We report here the results of a vaccination trial in baboons with the rlrV-5 or radiation-attenuated cercariae. rlrV-5 was presented either in the form of protein micelles or complexed with the outer membrane protein of meningococcus to form proteosomes. The level of protection achieved in these groups ranged from 0 to 54%, with a mean of 27.7%. In baboons exposed to radiation-attenuated cercariae the level of protection was very high, with a mean of 84%. The resistance observed after vaccination with rlrV-5 or radiation-attenuated cercariae was reflected in the overall histopathology. Vaccination of baboons with rlrV-5 or radiation-attenuated cercariae elicited an antibody response against epitopes exposed on the surface of newly transformed schistosomula. In the case of baboons vaccinated with radiation-attenuated cercariae, this response was not limited to epitopes encompassed by rlrV-5. Analysis of individual baboon sera by ELISA demonstrated that there was a direct correlation between the anti-rlrV-5 titer and resistance to challenge worm burden, suggesting that the immunoprotective mechanism is antibody-dependent.
Inhibition of murine B cell proliferation and down-regulation of protein kinase C levels by a phosphorylcholine-containing filarial excretory-secretory product.
Authors: Harnett W , Harnett M M 
Published: January 2023

Abstract
E-S 62, a major excretory-secretory product of the rodent filarial parasite, Acanthocheilonema viteae, inhibits the polyclonal activation (DNA synthesis) of mouse B cells by mitogenic anti-Ig antibodies. This effect appears to be due at least in part to the phosphorylcholine (PC) moiety of the molecule, because it can be mimicked by PC-BSA or PC-chloride. Activation of the B cells by LPS is not influenced by the presence of E-S 62/PC, suggesting that they may target some aspect of signaling via the Ag receptor. E-S 62/PC failed to inhibit surface Ig-mediated generation of the second messenger, inositol triphosphate, indicating that their target may not be the early biochemical events associated with activation. Exposure to E-S 62/PC was found to lead to a reduction in the level of protein kinase C, an important downstream regulatory enzyme, in anti-Ig-treated cells. This protein-kinase C down-regulation may be the biochemical mechanism underlying E-S 62/PC-mediated inhibition of surface Ig-activated B cells.
Inhibition of human CTL-mediated lysis by fibroblasts infected with herpes simplex virus.
Authors: Posavad C M , Newton J J , Rosenthal K L 
Published: January 2023

Abstract
Previously, we demonstrated that human anti-HSV CTL and allo-antigen-specific CTL were inhibited in lysing their normally sensitive target cells when they were exposed to human fibroblasts (FB) infected with herpes simplex virus (HSV). In this study, the mechanism of inhibition of CTL lytic function by FB infected with HSV-1 (HSV-FB) was studied. CTL exposed to HSV-FB early (2 h) in the infection cycle were inhibited by a mechanism that appears to be distinct from the inhibition of lytic function mediated by HSV-FB at late times (20 h) during the infection cycle. The inhibition of CTL-mediated lysis by FB infected with HSV-1 for 2 h required the expression of ICP4, an immediate-early protein of HSV-1, but not the production of infectious virus or virus-induced shut-off of host protein synthesis. In contrast, the expression of HSV-specific glycoproteins essential for viral infectivity (glycoproteins B, D, H, K, and L), and thus, infectious virus, was required for inhibition of CTL lytic function by FB infected with HSV-1 for 20 h. Further, CTL exposed to FB infected with HSV-1 for 20 h expressed HSV-specific proteins indicating that they were infected with HSV-1. Cell-to-cell spread of HSV-1 appeared to be the major mode of transmission because 1) an insufficient level of HSV-1 was present in the supernatant of HSV-FB to inhibit CTL lytic function; and 2) paraformaldehyde-fixed HSV-FB did not inhibit CTL-mediated lysis. The inhibition of CTL lytic function by HSV-FB may be an important mechanism of HSV-induced immunosuppression, permitting the virus to spread and persist in immunocompetent hosts after primary infection or reactivation of latent HSV.
Phospholipase A2 activity in human neutrophils. Stimulation by lipopolysaccharide and possible involvement in priming for an enhanced respiratory burst.
Authors: Forehand J R , Johnston R B , Bomalaski J S 
Published: January 2023

Abstract
Exposure to LPS, platelet-activating factor, certain cytokines, and other agents can prime human neutrophils for an increased release of superoxide anion (O2-) in response to stimuli. Previous work with LPS has suggested that priming may involve alterations in signal transduction pathways related to the release of O2-. Products derived from the enzymatic activity of phospholipase A2 (PLA2) on membrane phospholipids reportedly activate certain of these signaling events. Thus, PLA2 could play a regulatory role in the release of O2- by neutrophils. We examined this possibility by studying the effect of LPS on neutrophil PLA2 activity. Exposure to LPS triggered a fivefold increase in activity of an endogenous PLA2; control cells incubated under identical conditions without LPS showed no increase. Neutrophil-associated PLA2 activity increased 5 to 10 min after the addition of LPS to the cells and preceded the emergence of the primed state. Quinacrine and p-bromophenacylbromide, inhibitors of PLA2, blocked LPS priming but not the baseline O2- release from unprimed cells. The LPS-provoked increase in PLA2 activity resulted in release of oleic acid (38 +/- 4% above baseline) but not arachidonic, linoleic, or palmitic acid. In contrast, ionomycin resulted in significant release of all four fatty acids. The addition of exogenous PLA2 to neutrophils primed them. Priming was rapid and was 80 +/- 5% complete within 3 min. Thus, LPS and perhaps other agents may mediate their effects on O2- release at least in part by triggering PLA2 activity. PLA2 activation may play a role in regulating production and release of O2- by the human neutrophil.
Regulation of MCP-1/JE gene expression during monocytic differentiation.
Authors: Gruss H J , Brach M A , Schumann R R , Herrmann F 
Published: January 2023

Abstract
We examined the expression of the MCP-1/JE gene in freshly prepared human monocytes and again after either in vitro or in vivo maturation of these cells. We show that previously unstimulated blood monocytes of healthy individuals prepared by adherence procedures display high levels of MCP-1/JE mRNA and protein. Monocytes that were not previously exposed to activational plastic surfaces but were separated from other blood cells by counter-flow centrifugal elutriation expressed severalfold lower MCP-1/JE transcript and protein levels. Treatment of these cells with endotoxin was associated with the down-regulation of MCP-1/JE mRNA and protein levels. In contrast, exposure to IFN-gamma resulted in increased MCP-1/JE gene expression. During the process of in vitro maturation of monocytes into macrophages, a gradual decrease of MCP-1/JE mRNA and protein expression was noted. Both mature (day 8) blood monocyte-derived culture macrophages and peritoneal macrophages completely failed to express the MCP-1/JE gene, which could be restored after exposure to IFN-gamma and cross-linking of macrophage Fc gamma R with murine solid phase IgG2a mAbs; however, endotoxin failed to induce MCP-1/JE expression in these cells.
Phagocytic processing of exogenous particulate antigens by macrophages for presentation by class I MHC molecules.
Authors: Harding C V , Song R 
Published: January 2023

Abstract
Exogenous Ags that are processed in vacuolar endocytic compartments are generally presented by class II MHC molecules and not class I MHC (MHC-I) molecules, which conventionally present cytoplasmic or endogenous Ags. Accordingly, i.v. immunization of C57BL/6 mice with soluble OVA did not elicit a CD8 T cell response. However, i.v. immunization with OVA coupled to Latex particles (Latex-OVA) elicited an OVA-specific CD8 T cell response in vivo (particles from 59 to 2000 nm diameter were effective). In vitro, Latex-OVA was processed by H-2b macrophages and presented by Kb at least 100- to 1000-fold more efficiently than was soluble OVA. Inhibition of phagocytosis by cytochalasin D blocked the processing of Latex-OVA, whereas processing was not blocked by Brefeldin A. Latex-OVA was presented directly by H-2b macrophages or after "regurgitation" of processed OVA peptide from viable MHC-disparate macrophages for binding to surface Kb molecules on fixed H-2b macrophages. Peptide regurgitation was observed during processing of both Latex-OVA and Salmonella typhimurium 14028s that express an OVA fusion protein (Crl-OVA). However, the regurgitation pathway was less efficient than direct processing by viable H-2b macrophages. Thus, macrophages express an alternate pathway that allows MHC-I presentation of vacuolar exogenous particulate Ags, including inert synthetic particles without lipid membranes and intravacuolar bacteria. Peptides from these Ags are released from intracellular compartments to bind to surface MHC-I molecules, but peptide-MHC-I complexes also may be generated within intracellular compartments.
Regulation of human IgG subclass production by cytokines. IFN-gamma and IL-6 act antagonistically in the induction of human IgG1 but additively in the induction of IgG2.
Authors: Kawano Y , Noma T , Yata J 
Published: January 2023

Abstract
In this study, we investigated the roles of IFN-gamma and IL-6 in the induction of IgG subclasses from PBMC stimulated with PWM. The presence of IFN-gamma in the first half of the culture period dramatically suppressed the production of IgG1, whereas spontaneous IgG2 secretion was sharply enhanced by IFN-gamma when the latter was present throughout the culture period. Endogenous IFN-gamma was shown to be effective in IgG1 and IgG2 production because IgG1 production was enhanced and IgG2 production was inhibited by the addition of anti-IFN-gamma Ab. Because IFN-gamma did not act on the PBMC depleted of surface IgG2-bearing cells to enhance IgG2, IFN-gamma is unlikely to act as a switching factor. Differing from IFN-gamma, IL-6 enhanced every IgG subclass production as a nonswitching factor, although each of IgG subclasses required IL-6 differentially; maximal IgG1 responses and IgG4 responses occurred when IL-6 was present for the entire culture period or the last half of the culture period, whereas maximal IgG3 responses required the presence of IL-6 for the entire culture period and maximal IgG2 responses were seen when IL-6 was present solely during the last half of the culture period. IFN-gamma antagonized the synthesis of IgG1 by IL-6 and cooperated with IL-6 to produce IgG2. This observation was further supported by the fact that the IL-6-induced IgG1 and IgG2 enhancement were respectively up-regulated and down-regulated by anti-IFN-gamma. Altogether, the critical roles of IFN-gamma and IL-6 were implicated.
Association of Gm allotypes with the antibody response to the outer membrane proteins of a common upper respiratory tract organism, Moraxella catarrhalis.
Authors: Goldblatt D , Scadding G K , Lund V J , Wade A M , Turner M W , Pandey J P 
Published: January 2023

Abstract
Previously, Gm allotypes have been shown to influence human serum Ig subclass levels as well as the Ab levels achieved after Ag stimulation. The majority of the latter studies have focused on Ab responses to polysaccharide Ags. In this study, we have investigated the relationship between Gm allotypes and naturally occurring serum Ab levels to a bacterial protein Ag, the outer membrane proteins of a common microorganism, Moraxella catarrhalis. In the sera of 160 patients having chronic/recurrent sinusitis, there was a highly significant correlation between the level of specific anti-M. catarrhalis IgG3 level and certain Gm phenotypes. After additional investigation, we found that the presence of G3m(21) homozygosity correlated significantly with lower levels of Ag-specific IgG3. Specific anti-M. catarrhalis IgG3 levels were found to be independent of total serum IgG3 concentrations, and there was no correlation between the serum level of IgG3 and any Gm phenotype. Total IgG and IgG2 that were specific for pneumococcal cell wall polysaccharide also were measured in this group of patients, and no correlation was found between the naturally occurring IgG2 subclass levels to pneumococcal cell wall polysaccharide and the interactive effect of G2m(23) (syn: G2m(n)) and Km(1). Gm allotypes may influence Ab responses other than the anti-carbohydrate responses and, therefore, should be taken into account when investigating IgG subclass responses to protein Ags.