bluuebunny/crossref_metadata_2025 huggingface dataset:
Rejection of a nonimmunogenic melanoma by vaccination with natural melanoma peptides on engineered antigen-presenting cells.
Authors: Bellone M , Iezzi G , Martin-Fontecha A , Rivolta L , Manfredi A A , Protti M P , Freschi M , Dellabona P , Casorati G , Rugarli C
Published: December 2022

Naturally processed peptides, obtained by acid extraction of tumor cells, contain Ags able to activate specific CTL in vitro. We recently reported that the nonprofessional APC, RMA-S, expressing the B7.1 molecule (RMA-S/B7), pulsed with naturally processed peptides from the nonimmunogenic B16F1 melanoma (B16F1a.e.) primed syngenic CD8+ T cells against the tumor in vitro. Here, we show the rejection of B16F1 melanoma by C57BL/6 mice after immunization with RMA-S/B7 cells pulsed with B16F1a.e. This response is critically dependent on both CD4+ and CD8+ cells, but not on NK cells. However, only CD8+ T cells exert anti-B16F1 cytolitic activity in vitro. Moreover, RMA-S/B7 cells pulsed with B16F1a.e. can be used to prevent the growth of 24-h preestablished melanomas. These results may have important implications for the clinical use of natural peptide fractions of tumor cells as therapeutic cancer vaccines.
Antagonism of vaccine-induced HIV-1-specific CD4+ T cells by primary HIV-1 infection: potential mechanism of vaccine failure.
Authors: Kent S J , Greenberg P D , Hoffman M C , Akridge R E , McElrath M J
Published: December 2022

Prior immunity to HIV-1 elicited by vaccination may modify subsequent responses upon exposure to infectious HIV-1. An HIV-1-uninfected person entered in a vaccine trial that included immunizations to HIV-1(LAI) envelope with a recombinant vaccinia vector and recombinant protein developed envelope-specific CD4+ T cell responses, including proliferative and cytolytic responses, but was not protected from a high risk HIV-1 exposure. CD4+ T cell clones derived from blood at the peak of vaccine-induced immunity recognized and lysed autologous target cells expressing four distinct regions within the HIV-1(LAI) envelope region; three of these CTL clones also recognized targets expressing envelope from a similar viral subtype, HIV-1(MN). The epitope specificity of CD4+ clone 9G8, recognizing both HIV-1(LAI) and HIV-1(MN) envelope, was within the 571-590 amino acid envelope region. Sequence analysis of the first infectious autologous strain revealed two amino acid mutations within this region. The 9G8 CTL clone induced by immunization failed to recognize targets expressing the corresponding CTL epitope from the infecting virus. Moreover, a peptide based on the epitope sequence of the infecting isolate antagonized the vaccine-induced CTL clone such that the CTL clone was no longer able to recognize the vaccine strain or HIV-1(MN) epitope. These findings suggest a potentially novel mechanism associated with vaccine failure whereby the infecting virus may not only escape from CTL activity, but also alter the ability of CTL to recognize other variants in an individual.
IL-12 exacerbates helminth-mediated corneal pathology by augmenting inflammatory cell recruitment and chemokine expression.
Authors: Pearlman E , Lass J H , Bardenstein D S , Diaconu E , Hazlett F E , Albright J , Higgins A W , Kazura J W
Published: December 2022

Corneal inflammation (keratitis) is a major cause of visual impairment in Onchocerca volvulus infection. Previous studies showed that onchocercal keratitis can be induced in mice following s.c. immunization and intracorneal injection with soluble O. volvulus Ags (OvAg), and that the inflammatory response is dependent on T cells and IL-4. Since recombinant IL-12 impairs IL-4-dependent, Th2-mediated responses in other parasitic infections and in models of allergic asthma, the present study was undertaken to determine the effect of IL-12 on onchocercal keratitis. Mice were injected i.p. with IL-12 or saline at the time of initial sensitization to OvAg. Surprisingly, IL-12 treatment caused significant exacerbation of corneal pathology, which was associated with increased eosinophil and mononuclear cell infiltration into the corneal stroma. Consistent with the well-documented effect of IL-12 on Th1 cell development, corneas of IL-12-treated animals had elevated expression of the Th1 cytokine IFN-gamma and diminished expression of the Th2 cytokines IL-4, IL-5, IL-10, and IL-13. However, corneas from these animals also had marked elevation of alpha- and beta-chemokines known to be active on eosinophils and mononuclear cells, including IFN-gamma-inducible protein (IP)-10, macrophage inflammatory protein-1alpha, macrophage inflammatory protein-1beta, JE/monocyte chemotactic protein-1, RANTES (regulated upon activation, normal T expressed and secreted), and eotaxin. Together, these data indicate that IL-12 exacerbates OvAg-mediated corneal pathology by enhancing chemokine expression and recruitment of inflammatory cells.
Human monocyte adhesion is modulated by endothelin B receptor-coupled nitric oxide release.
Authors: King J M , Srivastava K D , Stefano G B , Bilfinger T V , Bahou W F , Magazine H I
Published: December 2022

Human monocytes have the capacity to produce both endothelin 1 (ET-1) and nitric oxide (NO), yet the roles of these mediators in monocyte function remain unclear. The relationship of ET-1 and NO release to monocyte adhesion was explored using peripheral blood monocytes (PBM) and the human monocytic cell lines THP-1 and U937. Specific binding of 125I-labeled ET-1 to THP-1 was abrogated by pretreatment with the endothelin B (ET(B)) receptor antagonist, BQ-788, but not by the endothelin A (ET(A)) receptor antagonist, BQ-123, consistent with predominant ET(B) receptor expression. Direct measurement of NO with an amperometric probe demonstrated the production of nanomolar concentrations of NO by PBM and THP-1 cells upon treatment with ET-1, which was abrogated by BQ-788, but not BQ-123, pretreatment, suggesting functional coupling of ET(B) receptors to NO release. Indeed, the presence of ET(B) receptor mRNA transcripts was detected in THP-1 and is consistent with previous reports that have demonstrated functional coupling of ET(B) receptors to constitutive NO synthase activation. In contrast, U937 cells did not release NO in response to ET-1 treatment, and mRNA transcripts were not detected in these cells, consistent their failure to bind 125I-labeled ET-1, as previously determined. Exposure of PBM to ET-1 markedly reduced the adhesion of these cells to human saphenous vein, whereas PBM adhesion in the presence of BQ-788 was restored to control levels. These data demonstrate that PBM interactions with the vascular wall can be reduced by autocrine production of NO and suggest that ET(B) receptors may attenuate monocyte activity at sites of inflammation.
Mechanism of sustained E-selectin expression in cultured human dermal microvascular endothelial cells.
Authors: Kluger M S , Johnson D R , Pober J S
Published: December 2022

Persistent E-selectin expression has been proposed to be a unique property of dermal vascular endothelium that directs skin-specific homing of a subpopulation of circulating memory T cells. We compared the kinetics of E-selectin expression on cultured human dermal microvascular endothelial cells (HDMEC) with expression on HUVEC. Following treatment with TNF, E-selectin on HDMEC appears more slowly than on HUVEC (peak values 6-8 vs 4 h, respectively) and is sustained at significantly higher levels after 24 h. E-selectin mRNA, analyzed by S1 nuclease protection, consists of a single predominant transcript that follows a similarly transient time course in both cell types. Cell surface E-selectin is internalized more slowly on HDMEC than on HUVEC (t1/2 = 4.3 vs 1.6 h, respectively) as measured by serial FACS analyses in the presence of the protein synthesis inhibitor cycloheximide. In comparison, intercellular adhesion molecule-1 (ICAM-1) expression is not measurably reduced by either cell type under the same conditions. HDMEC are similar to HUVEC in rates of pinocytosis or receptor-mediated endocytosis. Pulse-chase analysis indicated that the degradative half-life of E-selectin protein is greater in HDMEC than in HUVEC (1.9 vs 1.5 h, respectively). E-selectin internalization in microvascular endothelial cells (EC) from lung and subcutaneous fat is slow, like HDMEC, whereas internalization in large vessel EC from saphenous vein and aorta is rapid, like HUVEC. We conclude that HDMEC sustain higher levels of expression at 24 h by slower internalization and degradation of E-selectin protein and that this may be a general property of microvascular EC.
Regulation of inducible nitric oxide synthase messenger RNA expression and nitric oxide production by lipopolysaccharide in vivo: the roles of macrophages, endogenous IFN-gamma, and TNF receptor-1-mediated signaling.
Authors: Salkowski C A , Detore G , McNally R , van Rooijen N , Vogel S N
Published: December 2022

To evaluate potential roles for macrophages, IFN-gamma, and TNF receptor 1 (TNFR1) in the regulation of LPS-induced inducible nitric oxide synthase (iNOS) mRNA expression, we used a model of macrophage depletion as well as IFN-gamma (GKO) and TNFR1 (TNFR1 -/-) knockout mice. LPS-induced iNOS mRNA in spleen was ablated in both macrophage-depleted and GKO mice. In livers of macrophage-depleted mice, LPS-induced iNOS mRNA was reduced by 55 to 85%, with the most profound reductions detected 6 and 8 h after LPS injection. In GKO mice, peak iNOS mRNA expression in liver (3 h) was unaffected by the loss of endogenous IFN-gamma. By 6 to 12 h after LPS challenge, however, hepatic LPS-induced iNOS mRNA and serum nitrate/nitrite levels were reduced substantially in GKO mice. Residual LPS-induced iNOS mRNA in livers of GKO mice was nearly ablated by macrophage depletion, indicating that induction of iNOS mRNA in liver requires both endogenous IFN-gamma and either macrophages and/or macrophage-derived factors. TNFR1-mediated signaling was involved in the induction of LPS-induced iNOS mRNA in liver at 3 and 6 h, but not in its maintenance at 8 h. Conversely, induction of iNOS mRNA in spleen by LPS was independent of TNFR1-mediated signaling. Our results indicate that macrophages and/or their secreted products, endogenous IFN-gamma production, and TNFR1-mediated signaling play key roles in the in vivo regulation of iNOS mRNA expression and that the extent of their involvement is both time and organ specific.
IgE regulates mouse basophil Fc epsilon RI expression in vivo.
Authors: Lantz C S , Yamaguchi M , Oettgen H C , Katona I M , Miyajima I , Kinet J P , Galli S J
Published: December 2022

The binding of IgE to high-affinity IgE receptors (Fc epsilon RI) on the surface of mast cells and basophils primes these cells to secrete a panel of proinflammatory mediators upon subsequent exposure to specific Ag. We now find that the level of Fc epsilon RI expression on bone marrow basophils in mice infected with the nematode Strongyloides venezuelensis exhibits a strong positive correlation with the serum concentration of IgE, as was previously reported for human blood basophils. Moreover, the administration of IgE in vivo can significantly upregulate Fc epsilon RI expression on mouse basophils, and genetically IgE-deficient (IgE -/-) mice exhibit a dramatic (approximately 81%) reduction of basophil Fc epsilon RI expression compared with the corresponding normal (IgE +/+) mice. The finding that IgE can be a major regulator of mouse basophil Fc epsilon RI expression in vivo identifies a potentially important mechanism for enhancing the expression of effector cell function in IgE-dependent allergic reactions or immunologic responses to parasites.
Development of IFN-gamma-producing CD8+ gamma delta+ T lymphocytes and IL-2-producing CD4+ alpha beta+ T lymphocytes during contact sensitivity.
Authors: Dieli F , Asherson G L , Sireci G , Dominici R , Sciré E , Salerno A
Published: December 2022

This paper describes the development of Ag-specific proliferation and the production of IFN-gamma and IL-2 during contact sensitivity (CS) to the hapten picryl chloride (PCl). Lymph node cells from mice immunized with PCl proliferate and produce IFN-gamma and IL-2 when re-exposed to the specific Ag in vitro. Time course experiments showed that the peak IFN-gamma production occurred at days 3 and 4 after immunization, with a sharp decline by day 6. In contrast, proliferation and IL-2 production peaked at day 3 but persisted up to day 10. Proliferation and IFN-gamma and IL-2 production displayed by immune lymph node cells were Ag-specific but required different cell populations. In fact, the production of IFN-gamma was due to a CD8+, gamma delta+ T cell, while proliferation and IL-2 production required the presence of a CD4+, alpha beta+ T cell. Furthermore, IFN-gamma production showed genetic (MHC) restriction, and finer analysis using congenic strains of mice indicated that the K molecule was the restricting element. This was confirmed by blocking the K molecule of the APC used to trigger IFN-gamma production with a specific mAb. In contrast, proliferation and IL-2 production were I-A-restricted, as demonstrated using congenic strains of mice and blocking the I-A molecule of the APCs. Further analysis using purified gamma delta+ cells revealed that these cells produced IFN-gamma in an Ag-specific and MHC (K)-restricted fashion. Injection of mice with a mAb to IL-2 blocked subsequent in vitro proliferation, as well as IL-2 and IFN-gamma production, while all three in vitro responses were unaffected by injection of a mAb to IFN-gamma given at the time of immunization. Furthermore, injection of mice with a mAb to IL-2 blocked the CS reaction when given at the time of immunization, while it had no effect when given at the time of challenge. Injection of mice with mAb to IFN-gamma at the time of challenge reduced but did not abolished CS, suggesting that IFN-gamma is important but not exclusively responsible for the CS reaction.
Nuclear Rel-A and c-Rel protein complexes are differentially distributed within human thymocytes.
Authors: Feuillard J , Dargemont C , Ferreira V , Tarantino N , Debré P , Raphael M , Körner M
Published: December 2022

Nuclear factor-kappa B (NF-kappa B)/Rel proteins are inducible transcriptional regulators of numerous cellular genes. They are particularly abundant in lymphoid tissues and are thought to be critical for the transcription of genes involved in immune and inflammatory responses. We have reported previously that a nuclear NF-kappa B activity was present in freshly extracted human thymocytes in the absence of in vitro treatment of these cells. In the present report, we identified NF-kappa B proteins extracted from human thymocyte nuclei as being p50/p65 and p50/c-Rel complexes. Immunochemical and immunofluorescent staining of thymus sections using specific Abs allowed visualization of nuclear NF-kappa B proteins in both thymocytes and nonthymocyte cells. This detection suggested a preferential activation of p50/c-Rel in medullary thymocytes, whereas p50/p65 was present in both cortical and medullary regions of human thymus lobules. However, the intensity of p65 labeling was much higher in several thymocytes from the medulla. p65, p50, and c-Rel activities were found in both CD4- and CD8-positive thymocytes. These observations suggest that p65 and c-Rel complexes play distinct roles in gene expression and that both forms of NF-kappa B play critical roles during late stages of the intrathymic maturation of T cells.
Syk, but not Lyn, recruitment to B cell antigen receptor and activation following stimulation of CD45- B cells.
Authors: Pao L I , Cambier J C
Published: December 2022

B cell Ag receptor (BCR) signaling occurs via tyrosine phosphorylation of CD79a and CD79b ITAMs, leading to recruitment and activation of Lyn and Syk tyrosine kinases and subsequent downstream events. CD45 expression is required for BCR triggering of certain of these downstream events, such as calcium mobilization and p21ras activation. However, the site in the BCR signaling cascade at which CD45 impinges is poorly defined. To address this question, we have studied CD45 function in the CD45-deficient (CD45-) and CD45-reconstituted (CD45+) J558L mu m3 plasmacytoma. In both CD45+ and CD45- cells, Ag stimulation led to CD79a and CD79b tyrosine phosphorylation as well as Syk tyrosine phosphorylation, recruitment to the receptors, and activation. In contrast to CD45+ cells, Lyn exhibited high basal tyrosine phosphorylation in the CD45- cells and was not further phosphorylated upon Ag stimulation. Mapping studies indicated that the observed constitutive phosphorylation of Lyn reflects phosphorylation of its C-terminal tyrosine, Y508, at high stoichiometry. Constitutively Y508-phosphorylated Lyn was neither recruited to the BCR nor activated upon Ag stimulation. Moreover, CD79a-ITAM phosphopeptides failed to bind Lyn from the CD45- cells. Thus, Y508 phosphorylation of Lyn occurs in the absence of cellular CD45 expression and appears to render the kinase unable to associate with the phosphorylated receptor complex via its Src homology 2 domain and to participate in signal propagation. Surprisingly, in view of previous findings implicating Src family kinases in ITAM phosphorylation, the data indicate that Ag-induced CD79a and CD79b tyrosine phosphorylation and Syk recruitment and activation can occur in the absence of CD45 expression and, hence, Src-family kinase activation.
IL-2-regulated expression of the monocyte chemotactic protein-1 receptor (CCR2) in human NK cells: characterization of a predominant 3.4-kilobase transcript containing CCR2B and CCR2A sequences.
Authors: Polentarutti N , Allavena P , Bianchi G , Giardina G , Basile A , Sozzani S , Mantovani A , Introna M
Published: December 2022

NK cells migrate in response to C-C chemokines, including monocyte chemotactic protein-1 (MCP-1) and MCP-3. Increased migration was observed in IL-2-activated NK cells. It was therefore of interest to define the expression in resting and activated NK cells of the MCP-1 receptor (CCR2) for which two cDNAs (A and B) have been described. Specific oligonucleotides and reverse-transcriptase PCR revealed the presence in activated NK cells and mononuclear phagocytes of the fragments expected on the basis of the reported cDNAs. In addition, amplification with a common A/B- and an A-specific oligonucleotide yielded an unexpected, abundant, 1649-bp fragment. Sequence analysis as well as Northern blotting and RNase protection with different probes revealed that the CCR2 gene is expressed in activated NK cells and mononuclear phagocytes as a predominant long transcript (3.4 kb) consisting of CCR2B, followed by a novel sequence (X), corresponding to an intron in the genome, and by a CCR2A-specific portion. The predominant long transcript is polyadenylated and present in the cytoplasm. The augmented migratory capacity of IL-2 activated vs resting NK cells was associated with increased CCR2 transcript levels.
Cloned dendritic cells can present exogenous antigens on both MHC class I and class II molecules.
Authors: Shen Z , Reznikoff G , Dranoff G , Rock K L
Published: December 2022

Pathways for presenting proteins from the extracellular fluids on MHC class I molecules have been described in macrophages. However, it is uncertain whether similar mechanisms exist in dendritic cells, because conventional preparations of these cells can be contaminated with macrophages. We addressed this issue by transducing granulocyte-macrophage CSF into bone marrow cultures followed by supertransfection with myc and raf oncogenes. These immortalized clones displayed dendritic morphology, and many expressed the dendritic cell-specific markers DEC-205 and 33D1 as well as high levels of MHC molecules and costimulatory molecules. Using these cloned dendritic cells, we found that exogenous OVA could be presented on both their MHC class I and class II molecules. This presentation was markedly enhanced when the Ag was particulate and internalized by phagocytosis. Presentation of particulate OVA on MHC class I molecules was insensitive to the weak base chloroquine, but was blocked by peptide aldehyde inhibitors of the proteasome, indicating that the class I-presented peptides were generated in the cytosol. Brefeldin A, which inhibits the exocytosis of newly synthesized proteins from the endoplasmic reticulum, also inhibited Ag presentation. These results establish that dendritic cells can present exogenous Ags on MHC class I molecules and appear to use a similar phagosome to cytosol pathway as macrophages. Therefore, dendritic cells are likely to play an important role in generating immune responses to tissue transplants and tumors in vivo. Furthermore, these findings provide an approach for targeting vaccine Ags into these cells to prime immune responses in vivo.
The tetraspanin protein CD82 associates with both free HLA class I heavy chain and heterodimeric beta 2-microglobulin complexes.
Authors: Lagaudrière-Gesbert C , Lebel-Binay S , Wiertz E , Ploegh H L , Fradelizi D , Conjeaud H
Published: December 2022

CD82 is a tetraspan transmembrane protein on NK/LAK-susceptible targets. A single highly glycosylated protein of heterogeneous molecular mass (50-90 kDa) was immunoprecipitated by anti-CD82 from Nonidet P-40 lysates of various B cell lines, Raji, Daudi, 721, and 721.134. Using the milder detergent 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS), additional proteins were coprecipitated with CD82 from surface iodinated B cell lines, including a major band at 45 kDa, identified as the HLA class I heavy chain by sequential immunoprecipitations and sequential immunoprecipitation-Western blot analysis. Cocapping experiments confirmed the molecular association of CD82 and HLA class I at the cell surface of these B cell lines. CD82 could be coprecipitated with both mature and beta 2-microglobulin (beta 2m)-free heavy chains of MHC-I from CHAPS extracts. No association between MHC-I and CD82 was found in the beta 2m-deficient Daudi cell line or after co-in vitro translation of CD82, MHC heavy chain, and beta 2m mRNA. The most likely source of free class I heavy chains at the cell surface is by dissociation of beta 2m-associated class I molecules. These results suggest that association of CD82-MHC-I takes place at the cell surface and could interfere with the capacity of the MHC-I complex to protect targets from NK-mediated cytotoxicity.
Structural C3 diversity in fish: characterization of five forms of C3 in the diploid fish Sparus aurata.
Authors: Sunyer J O , Tort L , Lambris J D
Published: December 2022

In virtually all species examined to date, the functionally active third component of complement (C3) is encoded by a single gene. We have recently demonstrated, however, that trout possess three structurally and functionally distinct active C3 that represent the products of at least two different C3 genes. In the present study, we provide evidence that multiple forms of functional C3 occur not only in the rainbow trout (Salmo gairdneri), a quasi-tetraploid old teleost fish, but also in the diploid gilthead sea bream (Sparus aurata), a modern teleost fish. In the gilthead sea bream, we have characterized five different forms of C3 (C3-1, C3-2, C3-3, C3-4, and C3-5); in addition, we have identified and isolated a C5-like molecule. Each of the six proteins was composed of an alpha-chain and a beta-chain; however, only the C3 isoforms contained a thioester bond in their alpha-chains. These proteins all differed in the molecular masses of their alpha- and beta-chains and in their glycosylation patterns, reactivity with various Abs, tryptic peptide maps, and NH2-terminal sequences of their chains. These observations together with the fact that each of the six proteins were also purified from a single fish suggest that the C3 isoforms represent the products of several genes. The presence of multiple forms of C3 in a modern diploid fish, very distant in evolutionary time from the trout, strongly suggests that the C3 isoforms generated once from a single C3 gene have remained functional in the genomes of these animals. These findings not only have important consequences for our understanding of the evolution of the C3 protein, but also provide evidence for the formation and generation of a new C3-related gene family.
Nature and origin of polymorphism in feline MHC class II DRA and DRB genes.
Authors: Yuhki N , O'Brien S J
Published: December 2022

Transcripts of the MHC class II DRA and DRB gene homologues of the domestic cat (Felis catus) were cloned and sequenced to compare the pattern and process of DR gene divergence. Homologous DRB exon 2 sequences from 36 feral domestic cats throughout the world plus from three species of Felidae (tiger cat, Iriomote cat, and Geoffroy's cat) were also determined. Limited variation in the domestic cat Feca-DRA gene was observed, but abundant variation in the Feca-DRB gene was seen comprising 61 distinct DRB alleles. Phylogenetic analyses resolved at least five monophyletic feline DRB allelic lineages (DRB*1 to *5), which are clearly distinct from those of human (HLA-DRB1 to 9 lineages), mouse (H-2Ebeta b, u, f), and dog DRB alleles. Approximately 80% of individual cats contained three to six distinct DRB sequences, indicating that feline MHC maintains two to three DRB loci. Five cats had three DRB sequences in a single allelic lineage, indicating the occurrence of recent gene duplication of feline DRB genes. DRB sequences isolated from three exotic cats demonstrated close association with a particular domestic cat DRB lineage, suggesting that these allelic lineages are derived from common ancestral alleles that existed prior to the divergence of these feline species about 10 to 15 million years ago. Patterns of synonymous and nonsynonymous nucleotide substitution rates that occurred in Ag recognition sites (ARS) and nonrecognition (NAR) sites demonstrated a strong role of natural selection--positive selection for Ag recognition sites and negative selection for nonrecognition sites of feline DRB sequences--in the process of evolution of DR molecules.
A soluble chimeric complement inhibitory protein that possesses both decay-accelerating and factor I cofactor activities.
Authors: Higgins P J , Ko J L , Lobell R , Sardonini C , Alessi M K , Yeh C G
Published: December 2022

A chimeric gene was constructed from the genes coding for the human complement regulatory proteins, membrane cofactor protein (CD46) and decay-accelerating factor (CD55). The recombinant chimeric gene was transfected into Chinese hamster ovary cells. The gene product is a soluble, glycosylated, 110-kDa protein named complement activation blocker-2 (CAB-2). This protein possesses both factor I cofactor activity and decay-accelerating activity, and inactivates classical and alternative C3/C5 convertases in vitro. The specific activity of CAB-2 against cell-associated convertases is greater than that of soluble forms of either membrane cofactor protein or decay-accelerating factor or of both factors combined. CAB-2 also blocks the activation of complement in vivo, inhibiting both the Arthus reaction and Forssman shock in guinea pigs. Studies in rats demonstrate CAB-2 to exhibit favorable biphasic pharmacokinetics with a t1/2 alpha of 10 min and a t1/2 beta of 8 h; the beta phase accounts for 93% of the administered dose. CAB-2 may be an effective therapeutic treatment of acute human diseases in which excessive complement activation causes damage to normal tissues.
Human platelets can initiate T cell-dependent contact sensitivity through local serotonin release mediated by IgE antibodies.
Authors: Matsuda H , Ushio H , Geba G P , Askenase P W
Published: December 2022

To investigate the role of human platelets in initiating Ag-specific contact sensitivity (CS), a mouse model employing human platelets was used. Intravenous injection of immune lymphoid cells containing Ag-specific CS-effector Thy1+ B220- T cells that were depleted of CS-initiating Thy1+, B220+ cells together with human platelets presensitized in vitro with Ag-specific IgE mAb led to elicitation of CS responses in recipient mice. The fact that this response was blocked by preincubation of platelets with an irrelevant IgE or with a mixture of anti-Fc epsilonRI alpha mAb and anti-Fc epsilonRII mAb suggested that IgE Fc epsilonR on platelets were involved. When platelets that were presensitized with Ag-specific IgE mAb were incubated in vitro with specific Ag in the presence of fresh mouse serum, a significant net release of [3H]serotonin (5-hydroxytryptamine, 5-HT) was observed. Furthermore, in vitro depletion of 5-HT from platelets or in vivo pretreatment of recipients with a 5-HT2A receptor antagonist (ketanserin) abolished the IgE-dependent CS initiation mediated by platelets. These results show that human platelets can initiate T cell-dependent CS responses through IgE mAb, and this CS initiation is mediated by 5-HT released from the platelets in an Ag-specific manner.
IL-13 protects mice from lipopolysaccharide-induced lethal endotoxemia: correlation with down-modulation of TNF-alpha, IFN-gamma, and IL-12 production.
Authors: Muchamuel T , Menon S , Pisacane P , Howard M C , Cockayne D A
Published: December 2022

IL-13 is a potent down-modulator of macrophage proinflammatory activity in vitro, similar in this context to the anti-inflammatory cytokines IL-4 and IL-10. Since IL-10 effectively confers protection to mice from LPS-induced lethal endotoxemia through inhibition of proinflammatory cytokine production, we investigated whether IL-13 may also be capable of providing protection in this experimental model of endotoxic shock. A single injection of recombinant murine IL-13 (rmIL-13; 0.5-10 microg) significantly increased survival in a dose-dependent manner when a lethal i.p. injection of endotoxin was administered to BALB/c mice. This effect appeared to be IL-13 specific, since survival was not affected in mice that received heat-inactivated rmIL-13. rmIL-13 provided significant protection to mice even when given 30 min after LPS injection; however, this protection decreased in a time-dependent manner as the administration of rmIL-13 was delayed by 1, 2, and 5 h following LPS injection. The protective effect of IL-13 was correlated with significant decreases in the production of the inflammatory mediators TNF-alpha, IFN-gamma, and IL-12 as well as a decrease in the anti-inflammatory mediator IL-10. Our data suggest that IL-13 provides protection from LPS-induced lethal endotoxemia in a manner that is similar to but independent from that of IL-10, and therefore can be added to the list of cytokine immunomodulators that might be beneficial in the treatment of septic shock.
Constitutive tyrosine phosphorylation of the vav proto-oncogene product in MRL/Mp-lpr/lpr mice.
Authors: Mimura T , Minota S , Nojima Y , Morino N , Hamasaki K , Furuya H , Yazaki Y
Published: December 2022

MRL/Mp-lpr/lpr (lpr) mice develop autoantibodies, vasculitis, and glomerulonephritis, which are similar to human systemic lupus erythematosus, and acquire a generalized, nonmalignant, lymphoproliferative disorder. CD4- CD8- CD3+ TCR alphabeta+ (double-negative, DN) T cells accumulate in spleen and lymph nodes, and become a major T cell population in vivo. These DN T cells, however, are refractory to various stimuli, including CD3, IL-2, CD28, PMA, and PHA. Recently, the lpr gene mutation has been identified as a mutant gene for Fas, resulting in expression defects of Fas Ag. It is still unclear, however, what kinds of mechanisms cause the dysfunction of lpr DN T cells. To elucidate the pathogenic mechanisms in abnormal DN T cells, biochemical analyses were conducted for the expression and tyrosine phosphorylation of the vav proto-oncogene product (Vav) in DN T cells from lpr mice. We demonstrated that Vav, a 95-kDa cytoplasmic protein, from lpr mice was constitutively tyrosine phosphorylated several times higher than in control +/+ mice, while expression of Vav protein in lpr and +/+ mice was equal. Additionally, in contrast with +/+ T cells, tyrosine phosphorylation of Vav, which normally increases within a minute of stimulation via TCR, did not increase in lpr DN T cells following PHA or Ab activation. Taken together with the suggested roles of Vav in multiple receptor-mediated signal transductions, our findings suggest that the functional abnormalities of lpr DN T cells may be related to Vav abnormal tyrosine phosphorylation, which could lead to impaired signaling between surface receptors and G proteins in this cell population.
Origin and function of circulating CD44 in non-Hodgkin's lymphoma.
Authors: Ristämaki R , Joensuu H , Grön-Virta K , Salmi M , Jalkanen S
Published: December 2022

Soluble isoforms of various adhesion molecules have recently been found in the circulation, but the physiologic effects of such molecules are still unconfirmed. Our earlier study suggests that the serum level of the 70- to 80-kDa form of CD44 (sCD44) parallels the clinical treatment response in patients with lymphoma. In the present study we investigated the origin and the function of sCD44 in non-Hodgkin's lymphoma. Both peripheral blood and tumor lymphocytes were able to shed soluble CD44 in cell culture. In a SCID mouse model, transplanted Burkitt lymphoma (Namalwa) cells transfected with human CD44 shed soluble CD44. In binding studies sCD44 was able to adhere to hyaluronate and fibronectin, and moreover, sCD44 was able to block the binding of hyaluronate to CD44 on the cell surface and to block the binding of lymphocytes to high endothelial venules, suggesting that sCD44 retains its biological activity although it does not contain the cytoplasmic tail. In conclusion, sCD44 is biologically active and is at least partially shed by lymphoma cells in non-Hodgkin's lymphoma patients.
Kinetics of cytokine production in experimental systemic lupus erythematosus: involvement of T helper cell 1/T helper cell 2-type cytokines in disease.
Authors: Segal R , Bermas B L , Dayan M , Kalush F , Shearer G M , Mozes E
Published: December 2022

We followed cytokine production from induction through disease progression in a murine model of experimental systemic lupus erythematosus (SLE). SLE was induced by immunization with the human monoclonal anti-DNA Ab that bears the common Id designated 16/6 Id. BALB/c and C3H.SW mice that are susceptible to SLE induction and C57BL/6 mice that are resistant were immunized with the 16/6 Id. Cytokine production was tested periodically for 7 mo. Increased production of IL-2 and IFN-gamma, the Th1-type cytokines, was detected in BALB/c and C3H.SW mice 2 to 4 mo following immunization. IL-4 and IL-10, the Th2-type cytokines predominated later in disease course, and peaked 5 mo following disease induction. At this stage the Th1 type cytokines dropped to levels below those observed in controls. IL-4 production also dropped rapidly to very low levels, while IL-10 production decreased but remained above control levels. The ratio of IgG2a/IgG1 of DNA and 16/6 Id-specific Abs peaked at 2 mo following disease induction and decreased later, in concordance with the higher production of Th2-type cytokines. Thus, the development of experimental SLE in mice involves two stages: increased production of Th1-type, followed by increased induction of Th2-type cytokines. High levels of the proinflammatory cytokines, TNF-alpha and IL-1, were maintained throughout disease course. No significant changes were detected in the cytokine profile of C57BL/6 immunocytes following immunization with the 16/6 Id, supporting the possible role of the cytokine network in SLE.
CD3+ CD8+ CTL activity within the human female reproductive tract: influence of stage of the menstrual cycle and menopause.
Authors: White H D , Crassi K M , Givan A L , Stern J E , Gonzalez J L , Memoli V A , Green W R , Wira C R
Published: December 2022

The human female reproductive tract (RT) has been analyzed by others with respect to NK cell cytolytic activity, but not CD3+ T cell (CTL) cytolytic activity. Here, we describe the cytolytic capacity of mucosal CD3+ T cells both longitudinally within the RT (Fallopian tube, uterine endometrium, endocervix, ectocervix, and vaginal mucosa) and temporally throughout the menstrual cycle, using a redirected lysis assay system. Cytolysis by CD3+ CD8+ T cells is found throughout the RT and appears to be hormonally regulated, since in the uterine endometrium, the capacity for CD3+ T cell cytolytic activity is present during the proliferative phase of the menstrual cycle and absent during the subsequent secretory (postovulatory) phase. In contrast, in postmenopausal women the entire RT, including the uterus, retains the capacity for strong CD3+ T cell cytolytic activity. These findings suggest that the high levels of estradiol and progesterone present during days 14 to 28 of the menstrual cycle down-regulate CTL activity in the uterus. As a consequence, the absence of this activity may allow implantation of a semiallogeneic embryo that would otherwise be rejected. Further, these studies indicate that CTL activity is regulated differentially in different regions of the RT, persisting in the cervix and vagina throughout the menstrual cycle.
A Study of Vital Staining with Trypan Blue in Shock in Rabbits and Guinea Pigs
Authors: Ramsdell Susan Griffith
Published: December 2022

For the rabbit, the tissues of importance in the absorption of trypan blue from the circulation during shock were found to be the skin, the mucous membranes, the blood vessels and the liver. For the guinea pig, the only tissue of importance was the skin.

Since the appearance of the dye in the tissues is assumed to be only an indication of an edema, we may conclude that such a change can play no significant part in acute shock in the guinea pig, and that in the rabbit its effects are only indirect, producing the toxic rather than the acute syndrome usually manifested by this animal. But this is not to say that the first effect of an antigen-antibody reaction is not upon the capillary endothelium. Possibly the ensuing permeability is the first step in a stimulation of the smooth musculature so great, in the guinea pig, as to obscure the less spectacular oedema, especially since this last depends for its manifestation in a large measure both upon the time factor and a special type of tissue—rich in capillaries and connective tissue, which finds its highest development only in the skin.
Blood Groups in Peru, Santo Domingo, Yucatan and among the Mexicans at the Blue Ridge Prison Farm in Texas
Authors: Moss W. L. , Kennedy James A.
Published: December 2022

Introduction. During the last decade considerable interest has been manifest in determining the percentage distribution among the four blood groups of the population in the various countries of the world.

Geneticists have been active in collecting this data and have attempted to apply it to the investigation of racial origins and relationships.

It is generally accepted that the blood groups are hereditary characteristics, probably transmitted according to the Mendelian laws although there is not exact agreement as to the theories of the genetic formulae of the four groups.

During the world war Hirschfeld and Hirschfeld (1) determined the percentage of the four groups in 16 different peoples, examining approximately 500 individuals in each of the following nationalities: English, French, Italians, Germans, Austrians, Serbs, Greeks, Bulgarians, Arabs, Turks, Russians, Jews, Malagasies, Negroes (Senegal), Annamese, and Indians.
Inhibition of JAK3 and STAT6 Tyrosine Phosphorylation by the Immunosuppressive Drug Leflunomide Leads to a Block in IgG1 Production
Authors: Siemasko Karyn , Chong Anita S-F. , Jäck Hans-Martin , Gong Haihua , Williams James W. , Finnegan Alison
Published: December 2022

Leflunomide is an immunosuppressive drug capable of inhibiting T and B cell responses in vivo. A number of studies demonstrate that leflunomide functions both as a pyrimidine synthesis inhibitor and as a tyrosine kinase inhibitor. We previously reported that leflunomide inhibits LPS-stimulated B cell proliferation, cell cycle progression, and IgM secretion. This inhibition can be reversed by the addition of exogenous uridine, suggesting that leflunomide functions as a pyrimidine synthesis inhibitor in B cells. We report here that while the addition of uridine restored proliferation and IgM secretion to leflunomide-treated LPS-stimulated B cells, as determined by metabolic labeling and immunoprecipitation, it did not completely restore secretion of IgG Ab. We hypothesized that leflunomide inhibits LPS-induced IgG secretion by inhibiting tyrosine kinase activity required for isotype switch. We tested this hypothesis in a well-defined model of isotype switch, LPS plus IL-4 induction of IgG1. Leflunomide inhibited IgG1 secretion in this model in a dose-dependent manner. The signal transduction pathway utilized by IL-4 to induce IgG1 involves tyrosine phosphorylation of the IL-4 receptor, JAK1, JAK3, and STAT6 proteins induced by IL-4 binding to the IL-4R. Leflunomide diminished the tyrosine phosphorylation of JAK3 and STAT6 in the absence or presence of uridine. In gel mobility shift studies, STAT6 binding to the STAT6 DNA binding site in the IgG1 promoter decreased in the presence of leflunomide or leflunomide plus uridine. Taken together, these data suggest that leflunomide acts as a tyrosine kinase inhibitor to block IgG1 production.
Lack of Orally Induced Systemic Unresponsiveness in IFN-γ Knockout Mice
Authors: Kweon Mi-Na , Fujihashi Kohtaro , VanCott John L. , Higuchi Kazuo , Yamamoto Masafumi , McGhee Jerry R. , Kiyono Hiroshi
Published: December 2022

Splenic T cells isolated from BALB/c mice that had been mucosally tolerized by oral administration of 25 mg of OVA revealed selective increases in IFN-γ production with impaired levels of IL-2, IL-4, IL-5, and IL-10. These mice possessed reduced splenic OVA-specific T cell proliferative and delayed-type hypersensitivity responses when compared with nontolerized controls. Further, OVA-specific IgG Ab responses in serum and the numbers of IgG Ab-forming cells in spleen were significantly diminished following systemic challenge with OVA in CFA. When IFN-γ-deficient (IFN-γ−/−) mice of the same genetic background were given an oral dose of 25 mg of OVA before systemic immunization, no reduction in OVA-specific IgG Ab responses in serum and spleen was seen. Furthermore, the serum IgG Ab responses were restricted to IgG1 and IgG2b subclasses. Interestingly, although IFN-γ−/− mice displayed a partial diminishment of T cell proliferative and delayed-type hypersensitivity responses to OVA, significant responses were still present when compared with the low responses noted in IFN-γ+/+ mice. In addition, OVA-specific T cells from IFN-γ−/− mice produced Th2-type cytokines (e.g., IL-4), which provided help for systemic OVA-specific serum IgG1 and IgG2b Ab responses. These findings clearly indicate a central role for IFN-γ in the induction and maintenance of mucosally induced tolerance.
Early Intrathymic Precursor Cells Acquire a CD4low Phenotype
Authors: Michie Alison M. , Carlyle James R. , Zúñiga-Pflücker Juan Carlos
Published: December 2022

CD4low cells are a population of lymphoid lineage-restricted progenitor cells representing the earliest precursors present in the adult thymus. Paradoxically, thymic progenitors with a similar phenotype in fetal mice and adult RAG-2-deficient (RAG-2−/−) mice lack this characteristic low-level expression of CD4. We now show that radiation-induced differentiation of CD4+CD8+ double positive thymocytes in RAG-2−/− mice results in the appearance of low levels of CD4 on thymocytes that are phenotypically identical to CD4low progenitor cells present in the normal adult thymus. This suggests that CD4 surface expression can be passively transferred from double positive cells to early progenitor thymocytes. Analysis of mixed bone marrow chimeras, reconstituted with hematopoietic stem cells from both CD4−/− (CD45.2) and CD4wt (CD45.1) congenic mice, revealed a CD4low phenotype on cells derived from CD4−/− bone marrow cells. Furthermore, these CD4−/−-derived “CD4low” progenitors were capable of reconstituting lymphocyte-depleted fetal thymi, with all thymocytes displaying a CD4−/− phenotype. This directly demonstrates that genetically CD4-deficient thymic progenitor cells can passively acquire a CD4low phenotype. Moreover, CD4 expression on CD4low progenitor thymocytes is sensitive to mild acid treatment, indicating that CD4 may not exist as an integral cell surface molecule on this thymocyte population. Our findings demonstrate that low-level CD4 surface expression can be passively acquired by intrathymic progenitor cells from the surrounding thymic microenvironment, suggesting that other cell surface molecules expressed at low levels may also result from an acquired phenotype.
Enhanced Generation of Specific Tumor-Reactive CTL In Vitro by Selected Melan-A/MART-1 Immunodominant Peptide Analogues
Authors: Valmori Danila , Fonteneau Jean-François , Lizana Concepción Marañón , Gervois Nadine , Liénard Danielle , Rimoldi Donata , Jongeneel Victor , Jotereau Francine , Cerottini Jean-Charles , Romero Pedro
Published: December 2022

The Melan-A/MART-1 gene, which is expressed by normal melanocytes as well as by most fresh melanoma samples and melanoma cell lines, codes for Ags recognized by tumor-reactive CTL. HLA-A*0201-restricted Melan-A-specific CTL recognize primarily the Melan-A27-35 (AAGIGILTV) and the Melan-A26-35 (EAAGIGILTV) peptides. The sequences of these two peptides are not necessarily optimal as far as binding to HLA-A*0201 is concerned, since both lack one of the dominant anchor amino acid residues (leucine or methionine) at position 2. In this study we introduced single amino acid substitutions in either one of the two natural peptide sequences with the aim of improving peptide binding to HLA-A*0201 and/or recognition by specific CTL. Surprisingly, analogues of the Melan-A27-35 peptide, which bound more efficiently than the natural nonapeptide to HLA-A*0201, were poorly recognized by tumor-reactive CTL. In contrast, among the Melan-A26-35 peptide analogues tested, the peptide ELAGIGILTV was not only able to display stable binding to HLA-A2.1 but was also recognized more efficiently than the natural peptide by two short-term cultured tumor-infiltrated lymph node cell cultures as well as by five of five tumor-reactive CTL clones. Moreover, in vitro generation of tumor-reactive CTL by stimulation of PBMC from HLA-A*0201 melanoma patients with this particular peptide analogue was much more efficient than that observed with either one of the two natural peptides. These results suggest that the Melan-A26-35 peptide analogue ELAGIGILTV may be more immunogenic than the natural peptides in HLA-A*0201 melanoma patients and should thus be considered as a candidate for future peptide-based vaccine trials.
Structure-Function Study of the Extracellular Domain of the Human IFN-α Receptor (hIFNAR1) Using Blocking Monoclonal Antibodies: The Role of Domains 1 and 2
Authors: Lu Ji , Chuntharapai Anan , Beck Joanne , Bass Steve , Ow Arlene , De Vos Abraham M. , Gibbs Verna , Kim K. Jin
Published: December 2022

We have performed a structure-function analysis of extracellular domain regions of the human IFN-α receptor (hIFNAR1) using mAbs generated by immunizing mice with a soluble hIFNAR1-IgG. Five mAbs described in this study recognize different epitopes as determined by a competitive binding ELISA and by alanine substitution mutant analyses of the hIFNAR1-IgG. Two mAbs, 2E1 and 4A7, are able to block IFN-stimulated gene factor 3 (ISGF3) formation and inhibit the antiviral cytopathic effect induced by several IFN-α (IFN-α2/1, -α1, -α2, -α5, and -α8). None of these anti-IFNAR1 mAbs were able to block activity of IFN-β. mAb 4A7 binds to a domain 1-hIFNAR1-IgG but not to a domain 2-hIFNAR1-IgG, which suggests that its binding region is located in domain 1. The binding of the most potent blocking mAb, 2E1, requires the presence of domain 1 and domain 2. The most critical residue for 2E1 binding is a lysine residue at position 249, which is in domain 2. These findings suggest that both domain 1 and domain 2 are necessary to form a functional receptor and that a region in domain 2 is important. IFN-β recognizes regions of the hIFNAR complex that are distinct from those important for the IFN-α.