bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of in vivo inhibition of nitric oxide production in murine leishmaniasis.
Authors: Evans T G , Thai L , Granger D L , Hibbs J B 
Published: January 2023

Abstract
In vitro experiments suggest that cytokine induced nitric oxide (NO) synthesis from L-arginine is a major effector mechanism against prokaryotic and eukaryotic intracellular pathogens. N omega monomethyl L-arginine (MLA), an active site inhibitor of the cytokine induced NO synthase, inhibits cytokine induced resistance of mammalian cells to intracellular microbes in vitro. In our experiments, we show that Leishmania infection markedly increases NO synthesis in the genetically resistant C3H/HeN mouse strain. In addition, administration of 50 mM MLA in the drinking water inhibits endogenous NO synthesis as well as natural resistance to footpad Leishmania infections in both susceptible BALB/c and resistant C3H/HeN mice. Leishmania parasites continued to proliferate in MLA-treated C3H/HeN mice after footpad inoculation. Similarly C3H/HeN mice treated for 3 wk with MLA had an increased parasite load and sloughing of the footpad. Footpad size of C3H/HeN mice not treated with MLA returned to base-line diameter and the regional nodes contained few amastigotes. These in vivo effects were paralleled by endogenous NO synthesis (high when Leishmania was controlled and low when Leishmania was not controlled). In addition, inhibition of NO synthesis in Leishmania-infected mice leads to a cachectic state not caused by infection alone or inhibition of NO synthesis alone. The cachexia appeared to be due to decreased food intake that occurs when NO synthesis is inhibited in Leishmania-infected mice. Our results show that cytokine induced NO has a major effector role in resistance of murine hosts to Leishmania infection.
IFN-gamma involvement in the severity of gram-negative infections in mice.
Authors: Kohler J , Heumann D , Garotta G , LeRoy D , Bailat S , Barras C , Baumgartner J D , Glauser M P 
Published: January 2023

Abstract
The role of IFN-gamma in the regulation of inflammation leading to gram-negative septic shock is still poorly understood. IFN-gamma blockade has been shown to improve the survival of animals challenged with i.v. bolus injections of LPS and gram-negative bacteria. We have investigated a model of focal Escherichia coli infection leading to peritonitis and septic shock. Mice were challenged i.p. with an inoculum near the LD50. The addition of rIFN-gamma together with bacteria increased the mortality and the level of blood TNF-alpha and IL-6. Conversely blockade of IFN-gamma with a neutralizing mAb significantly improved the survival of the mice. This beneficial effect was not associated with a stringent decrease in blood bacterial counts and TNF-alpha and IL-6 levels in survivors. In this model, the protective effect of anti-IFN-gamma mAb contrasted with the ineffectiveness of a neutralizing anti-TNF-alpha mAb. These findings suggest that overproduction of IFN-gamma might have a more detrimental role than overproduction of TNF-alpha during focal gram-negative infections.
Binding, internalization, and deacylation of bacterial lipopolysaccharide by human neutrophils.
Authors: Luchi M , Munford R S 
Published: January 2023

Abstract
Bacterial LPS is a potent agonist for priming and stimulating neutrophils (PMN). Although much has recently been learned about the binding receptors for LPS on these and other cells, little is known about the subsequent fate of LPS that has bound to the cell surface. In these studies, we evaluated three events in the interaction of Escherichia coli [3H]LPS with human PMN: 1) binding to the plasma membrane; 2) translocation to an intracellular compartment; and 3) enzymatic deacylation. Our results suggest that PMN bind LPS by at least two mechanisms: when serum is present, LPS binds almost entirely to CD14, whereas in the absence of serum, other binding mechanisms predominate. Serum thus augments CD14-mediated LPS binding, although the total amount of cell-associated LPS increases only by a factor of two, on average, when serum is added. Binding outpaces intracellular movement of the LPS, yet at least 1%/min of the cell-associated LPS is translocated to an intracellular compartment. In the absence of serum, LPS internalization occurs in the presence of a mAb that blocks LPS-CD14 binding, suggesting that an interaction with CD14 is not essential for LPS to traffic beyond the plasma membrane. LPS deacylation, which occurs over several hours, is inhibited by agents that reduce lysosomal (endosomal) acidification. This finding is consistent with a deacylating role for acyloxyacyl hydrolase, which has an acid pH optimum, and suggests that LPS moves at least transiently into an acidic intracellular compartment. These experiments provide a new temporal framework for evaluating LPS-neutrophil interactions.
Cytoplasmic tails of human complement receptor type 3 (CR3, CD11b/CD18) regulate ligand avidity and the internalization of occupied receptors.
Authors: Rabb H , Michishita M , Sharma C P , Brown D , Arnaout M A 
Published: January 2023

Abstract
To evaluate the role of the cytoplasmic tails of CD11b and CD18 in ligand binding and internalization of the human complement receptor type 3 (CR3, CD11b/CD18), wild type, and truncation mutants of CD11b and CD18 cDNA were expressed in COS fibroblastoid cells and assayed for surface membrane expression, ligand binding, and internalization. Truncated CD11b (alpha 1119T) and CD18 (beta 728T) subunits retaining, respectively, two and five residues of the putative cytoplasmic tails were generated by in vitro mutagenesis. Binding of alpha 1119T beta and alpha beta 728T heterodimeric receptors to iC3b was increased by 330% and 210%, respectively, relative to wild type CR3, suggesting that both cytoplasmic tails of CR3 negatively control receptor avidity. Internalization of antibody cross-linked wild type CR3 occurred predominantly through coated pits. Truncation of the cytoplasmic tail of CD18 but not of CD11b markedly reduced coated pit internalization of CR3, an effect also produced by a single F754A mutation involving one of two putative NPXF internalization signals in CD18.
CD48 is a low affinity ligand for human CD2.
Authors: Sandrin M S , Mouhtouris E , Vaughan H A , Warren H S , Parish C R 
Published: January 2023

Abstract
COS cells transiently transfected with human CD48 were found to bind human PBL, whereas mock or CD7-transfected COS cells failed to bind human lymphocytes. Binding of PBL to CD48 transfectants was almost totally inhibited by either CD48 mAb pretreatment of COS cells or CD2 mAb pretreatment of PBL, implying an interaction between CD2 and CD48. This conclusion was confirmed by the demonstration that a highly fluorescent, multimeric form of rCD2 bound to CD48 transfected COS cells in a CD48-dependent manner. Additional mAb blocking studies revealed that CD48 interacts with the T11(1) region of CD2, the same region of CD2 that binds LFA-3 (CD58). Thus, CD48 and CD58 represent alternative and possibly competing ligands for CD2, although based on blocking studies with soluble CD2, CD48 interacts with CD2 with approximately a 100-fold lower affinity that CD58.
Characterization of a cell surface glycoprotein IPO-3, expressed on activated human B and T lymphocytes.
Authors: Sidorenko S P , Clark E A 
Published: January 2023

Abstract
We characterize the expression, biochemical structure, and function of a novel glycoprotein, IPO-3, up-regulated on activated human lymphocytes. IPO-3 is found on activated B cells, B cell lines, and hairy cell leukemias but is not expressed on T cell or nonlymphoid cell lines. IPO-3 is not B cell-specific as it is detected at low levels on CD45RO+ CD45RA- peripheral blood T cells and CD4+CD8+CD45RO+ CD45RA- thymocytes. The IPO-3 Ag is a single-chain heavily N-glycosylated phosphoglycoprotein approximately 75 to 95 kDa in size with a 42-kDa protein core. In vitro kinase assays revealed that IPO-3 has a protein kinase activity associated with it that is maintained even in Nonidet P-40 lysates. IPO-3 is up-regulated on resting B cells within 16 h after activation with different signals including anti-IgM, IL-4, or mAb to CD40, CD20, or Bgp95. It could also be induced on T cells via CD3-cross-linking, but the kinetics of IPO-3 induction was slower on T cells than on B cells. Cross-linking IPO-3 on B cells with mAb did not induce proliferation alone but did augment proliferation promoted by IL-4 and anti-CD40 and did trigger increases in [Ca2+]i in resting B cells. Binding of IPO-3 could not be inhibited by a variety of mAb to previously identified activation markers. Thus, the IPO-3 glycoprotein appears to be a novel marker of activated B and T lymphocytes, which may play a role in the regulation of lymphocyte activation.
Unexpected lack of reactivity of allogeneic anti-Ia monoclonal antibodies with MHC class II molecules expressed by mouse intestinal epithelial cells.
Authors: Vidal K , Samarut C , Magaud J P , Revillard J P , Kaiserlian D 
Published: January 2023

Abstract
We have examined MHC class II molecules expression by murine gut epithelial cells using a large panel of anti-Ia antibodies. In contrast to conventional APC (i.e., B cells and macrophages), only two anti-Ia antibodies reacted with enterocytes: a xenogeneic rat anti-Ia mAb (CD311) directed against a monomorphic class II determinant, and a polyclonal antiserum directed against both I-A and I-E heterodimers. In contrast, allogeneic anti-Ia mAb were either unreactive (17 of 20) or reacted weakly (3 of 20) with enterocytes, even after in vivo treatment with IFN-gamma. This pattern of Ia reactivity of epithelial cells was tissue specific (restricted to gut mucosa) and cell specific (restricted to gut epithelial cells). Biochemical and molecular studies confirmed that enterocytes expressed I-A and I-E isotypes on their cell surface and contained mRNA of both subregion loci. Interestingly, enterocytes appeared deficient in expression of the MHC class II-associated invariant chain, and are not able to stimulate allogeneic T cells. These data suggest that gut epithelial cells express a conformation of class II molecules, antigenically distinct from that expressed on conventional APC.
Structural analysis of the CD3 zeta/eta locus of the rat. Expression of zeta but not eta transcripts by rat T cells.
Authors: Itoh Y , Matsuura A , Kinebuchi M , Honda R , Takayama S , Ichimiya S , Kon S , Kikuchi K 
Published: January 2023

Abstract
We analyzed the structure and pattern of expression of rat TCR zeta- and eta-chains to investigate if these components function in activation and development of rat T cells. The rat zeta cDNA contained the complete open reading frame coding for a polypeptide of 164 amino acids and the 5' and 3' noncoding sequences. Comparison of the amino acid sequence to those of mouse and human counterparts revealed a high degree of similarity, more than 85% homology among all three species except for the signal peptide, which was especially high in the cytoplasmic domain including the nucleotide binding site and the possible tyrosine phosphorylation sites. Furthermore, we determined the nucleotide sequences of a rat genomic eta-like sequence located in the 3' region of the rat zeta-gene. Although it showed a high level of nucleotide similarity to mouse and human counterparts, 90.4 and 78.9%, respectively, the deduced polypeptide was very short (only 28 residues) and markedly divergent from the mouse and human eta-specific polypeptides due to frameshift mutations. Transcription of rat zeta was shown to be highly restricted to T cells; abundantly in thymocytes and scarcely in peripheral T cells. Surprisingly, the rat eta transcript could not be detected in any rat tissues so far tested by Northern blot analysis and even by the sensitive reverse transcription-polymerase chain reaction method, whereas it was readily detected in mouse thymus. These findings suggest that the zeta-chain has conserved roles in the TCR assembly and TCR-mediated signaling. However, the eta-chain seems not to be indispensable because of its structural diversity among these three species characterized to date and the apparent lack of eta expression in the rat.
Switch recombination breakpoints occur at nonrandom positions in the S gamma tandem repeat.
Authors: Kenter A L , Wuerffel R , Sen R , Jamieson C E , Merkulov G V 
Published: January 2023

Abstract
Ig switch (S) recombination is clearly focused on S regions. It is possible that S-specific DNA binding proteins facilitate the alignment of these regions before recombination. The S gamma 3-specific DNA binding proteins, SNAP and SNIP/NF-kappa B, interact with two discrete regions of the S gamma 3 tandem repeat, the A and B sites. Recombination breakpoints in the S gamma 3 region were found to significantly correlate with the binding sites of the S gamma 3 binding proteins. We now report the conservation of the SNIP and SNAP binding sites in S gamma 2b and S gamma 1 DNA. SNIP/NF-kappa B interacts with its cognate sites in S gamma 2b and S gamma 1 DNA as determined by mobility shift assays, competition binding studies, and supershift analysis using an antiserum specific for the p50 component. SNAP binds specifically to S gamma 2b and S gamma 1 as measured by mobility shift assays and competition binding studies. SNAP is composed of two closely traveling mobilities that do not separate on partial purification. SNIP and SNAP are expressed in nuclear extracts derived from murine splenic B cell cultures stimulated with mitogen or mitogen and IL-4. No new DNA binding proteins specific for S gamma 1 tandem repeats are detectable in nuclear extracts from B cells stimulated with mitogen and IL-4. The sites at which recombination occurs in the S gamma 2b and S gamma 1 regions have been analyzed statistically and found to correlate with the SNIP/NF-kappa B and SNAP binding sites. Distinctions have been found regarding the use of DNA substrates within the tandem repeat between primary (mu--&gt;gamma) and successive (gamma--&gt;x) S recombination.
Self-peptides from four HLA-DR alleles share hydrophobic anchor residues near the NH2-terminal including proline as a stop signal for trimming.
Authors: Kropshofer H , Max H , Halder T , Kalbus M , Muller C A , Kalbacher H 
Published: January 2023

Abstract
Naturally processed MHC class II-associated peptides proved to be heterogeneous in size, varying from 13 to 25 amino acids. Truncation variants suggested sequence motifs that afford the amino termini to be shifted for obtaining an alignment: a 9- to 11-residue core region that is bordered by primary anchor residues is surrounded by extra sequences of variable lengths and hitherto unknown functions. Herein we present bulk sequencing analyses of self-peptides from four HLA-DR alleles and HLA-DQw7 clearly showing that the length of most of the NH2-terminal preanchor sequence is limited to 1 to 3 residues. Most strikingly, proline is the dominant residue reappearing at positions 2 and 3 in any allele. Proline revealed to function as a stop signal for NH2-terminal trimming as well as a secondary anchor: crude cytosolic and endosomal peptide fractions could be processed by aminopeptidases in vitro, whereupon DR1 binding peptides with increased affinity were generated. In addition, aminopeptidase treatment of DR1: self-peptide complexes implied that proline together with sterical constraints of the MHC molecule do protect the peptides' NH2-termini from further processing, whereas their COOH-termini were accessible to cathepsin B processing. Finally, bulk sequencing profiles contained signals from further putative anchor residues clustering in the NH2-terminal region:tyrosine, phenylalanine, leucine, isoleucine, and valine are enriched at positions 2 to 4 in DR1, DR5, and DR6, however, at positions 4 to 6 in DR3. Isotype-specificity is demonstrated by DQw7 displaying glutamine and asparagine at position 2. Obviously, the degenerate occurrence of aromatic or aliphatic side chains close to the NH2-terminal guarantees for essential interactions with a hydrophobic pocket of the investigated DR molecules. Most probably, this pocket is located in the nonpolymorphic DR alpha-chain rationalizing previous findings of promiscuous peptide binding to different DR alleles.
Biochemical identity of the mouse Ly-19.2 and Ly-32.2 alloantigens with the B cell differentiation antigen Lyb-2/CD72.
Authors: Robinson W H , Landolfi M M , Schäfer H , Parnes J R 
Published: January 2023

Abstract
Lyb-2/CD72 is a 45-kDa mouse B cell surface protein that binds CD5 (Ly-1) and has been shown to induce B cell proliferation upon mAb binding. The serologically defined Ly-19.2 and Ly-32.2 lymphocyte alloantigens have mouse strain distribution patterns similar to that of the Lyb-2/CD72 alleles and map to the same region on chromosome 4 as Lyb-2/CD72. Our recent isolation of the Lyb-2a, -2b, and -2c cDNA has enabled us in this report to examine the relationship between Ly-19, Ly-32, and Lyb-2/CD72. A rat T cell line transfected with a mouse Lyb-2a cDNA is recognized by Ly-19.2-specific mAb, whereas transfectants expressing the Lyb-2b cDNA are recognized by both Ly-19.2 and Ly-32.2-specific mAb. Cell surface iodination immunoprecipitation analysis from Lyb-2a cDNA transfectants using Lyb-2a- and Ly-19.2-specific mAb as well as from Lyb-2b cDNA transfectants using Lyb-2b-, Ly-19.2-, and Ly-32.2-specific Ab, produced immunoprecipitates containing comigrating 45-kDa polypeptides. Preclearing studies with these transfectants indicate that the immunoprecipitated proteins represent the same polypeptide chain. These results demonstrate that the mouse Ly-19.2 and Ly-32.2 alloantigens are in fact the B cell differentiation Ag Lyb-2/CD72.
cDNA cloning of a major allergen from timothy grass (Phleum pratense) pollen; characterization of the recombinant Phl pV allergen.
Authors: Vrtala S , Sperr W R , Reimitzer I , van Ree R , Laffer S , Müller W D , Valent P , Lechner K , Rumpold H , Kraft D 
Published: January 2023

Abstract
We isolated a cDNA encoding a major grass pollen allergen from a timothy grass (Phleum pratense) pollen expression cDNA library using allergic patients' IgE. The complete cDNA encoded an allergen that binds IgE from about 80% of grass pollen-allergic patients. Significant sequence homology was found to other major grass pollen allergens from Kentucky bluegrass (Poa pratense) as well as from rye grass (Lolium perenne) which originally were believed to form different identities. Using different monoclonal and polyclonal antibodies raised against group V allergens we identified the recombinant protein as a group V allergen from timothy grass, Phl p V. In IgE-binding studies it is demonstrated that the rPhl p V allergen can be used to block binding of patients' IgE to natural group V isoallergens on two-dimensional immunoblots. IgE inhibition experiments show that up to 60% of grass pollenspecific IgE can be preadsorbed with the rPhl p V allergen from patients sera. The purified rPhl p V induced specific histamine release of blood basophils from grass pollen-allergic patients. This emphasizes the usefulness of the rPhl p V for diagnostic and therapeutic purposes and corroborates the view that specific diagnosis and therapy of type l allergy could be performed with a limited panel of relevant recombinant allergens.
Expression of a protective intestinal immune response can be inhibited at three distinct sites by treatment with anti-alpha 4 integrin.
Authors: Bell R G , Issekutz T 
Published: January 2023

Abstract
The alpha 4 integrins mediate lymphocyte adhesion to Peyer's patch high endothelial vessels and homing to Peyer's patch, as well as to mesenteric lymph nodes. In rats, immunity to infection with the nematode Trichinella spiralis is known to be mediated by CD4+ OX22- (CD45RC-) cells that home to the intestine in large numbers. These experiments were conducted to determine whether the alpha 4 integrins or LFA-1 were involved in the expression of intestinal immunity to T. spiralis. Injection of the anti-alpha 4 integrin, mAb TA-2, but not anti-LFA-1, mAb TA-3, impaired the expression of immunity. An effect of TA-2 was measured at three distinct sites along the activation pathway leading to the migration of protective CD4+ OX22- cells to the intestine. Injection of TA-2 on the same day as infection prevented normal rejection of the parasite and abrogated the characteristic appearance of blast cells in draining lymph 3 days after infection. A similar effect on the migration of blast cells at day 3 was seen when TA-2 was injected 1 day after infection, and injection 2 days after infection still reduced the number of protective cells entering TD lymph on day 3. The effect of TA-2 and TA-3 on homing of dividing cells to the gut was examined by injecting dividing cells i.v. at the same time as antibody. Under these conditions migration of dividing cells to the gut was reduced by 90 to 95% and their capacity to adoptively transfer worm rejection blocked. Furthermore, TA-2 treatment also inhibited protection when it was injected 12, 18, or 24 h after the transfer of protective cells, when these cells had already entered the gut, but not when TA-2 injection was delayed for 36 h. These results indicate the involvement of alpha 4 integrins at the following points in the generation, dissemination, and function of CD4+ OX22- effectors: 1) initial activation during the first 48 h of infection; 2) migration of protective cells to and extravasation in the gut; 3) a function after entry into gut tissues. The results suggest that entry of dividing cells into the gut is critical for the adoptive transfer of protection and that alpha 4 integrin has multiple roles in the manifestation of intestinal immunity.
Profiles of cytokine production in relation with susceptibility to cerebral malaria.
Authors: de Kossodo S , Grau G E 
Published: January 2023

Abstract
Infection with Plasmodium berghei ANKA (PbA) leads, in susceptible strains of mice, to the development of cerebral malaria (CM), a lethal syndrome that reproduces some features of human CM. To study a possible relationship between genetic susceptibility to CM and the cytokine expression pattern, we quantitatively evaluated gene expression on RNA extracted from various organs of malaria-infected mice, using strains that are susceptible and resistant to CM. Northern blot analysis and semi-quantitative PCR showed that CM is associated with an increased TNF-alpha mRNA accumulation in the brain of mice developing the neurologic complications of CM. An increased IFN-gamma mRNA accumulation and a decreased expression of IL-4 and TGF-beta genes were also observed in mice susceptible to CM. In vitro restimulation studies using crude malarial Ag showed that lymphoid cell proliferation was higher in CM-susceptible than in CM-resistant infected mice. Moreover, susceptible mice produced large amounts of IFN-gamma, in a dose-dependent manner, in response to PbA Ag, whereas cells from resistant mice failed to produce significant amounts of this cytokine. Conversely, IL-2 and IL-4 production was significantly higher in infected CM-resistant mouse cells. No difference was seen in the production of IL-3 and IL-5 between resistant and susceptible PbA-infected mice. Upon stimulation with various malarial Ag, comparable amounts of TNF-alpha were produced by macrophages of either strain of mice. Taken together, these findings indicate that susceptibility to CM resides at the level of T cells rather than macrophages. Furthermore, the cytokine production profile is consistent with a predominant Th1-like response in mice developing cerebral complications of malaria.