bluuebunny/crossref_metadata_2025_split huggingface dataset:
Efficient Isolation of Novel Human Monoclonal Antibodies with Neutralizing Activity Against HIV-1 from Transgenic Mice Expressing Human Ig Loci
Authors: He Yuxian , Honnen William J. , Krachmarov Chavdar P. , Burkhart Michael , Kayman Samuel C. , Corvalan Jose , Pinter Abraham 
Published: April 2014

Abstract
Despite considerable interest in the isolation of mAbs with potent neutralization activity against primary HIV-1 isolates, both for identifying useful targets for vaccine development and for the development of therapeutically useful reagents against HIV-1 infection, a relatively limited number of such reagents have been isolated to date. Human mAbs (hu-mAbs) are preferable to rodent mAbs for treatment of humans, but isolation of hu-mAbs from HIV-infected subjects by standard methods of EBV transformation of B cells or phage display of Ig libraries is inefficient and limited by the inability to control or define the original immunogen. An alternative approach for the isolation of hu-mAbs has been provided by the development of transgenic mice that produce fully hu-mAbs. In this report, we show that immunizing the XenoMouse G2 strain with native recombinant gp120 derived from HIVSF162 resulted in robust humoral Ab responses against gp120 and allowed the efficient isolation of hybridomas producing specific hu-mAbs directed against multiple regions and epitopes of gp120. hu-mAbs possessing strong neutralizing activity against the autologous HIVSF162 strain were obtained. The epitopes recognized were located in three previously described neutralization domains, the V2-, V3- and CD4-binding domains, and in a novel neutralization domain, the highly variable C-terminal region of the V1 loop. This is the first report of neutralizing mAbs directed at targets in the V1 region. Furthermore, the V2 and V3 epitopes recognized by neutralizing hu-mAbs were distinct from those of previously described human and rodent mAbs and included an epitope requiring a full length V3 loop peptide for effective presentation. These results further our understanding of neutralization targets for primary, R5 HIV-1 viruses and demonstrate the utility of the XenoMouse system for identifying new and interesting epitopes on HIV-1.
Src-Dependent Syk Activation Controls CD69-Mediated Signaling and Function on Human NK Cells
Authors: Pisegna Simona , Zingoni Alessandra , Pirozzi Gianluca , Cinque Benedetta , Cifone Maria Grazia , Morrone Stefania , Piccoli Mario , Frati Luigi , Palmieri Gabriella , Santoni Angela 
Published: April 2014

Abstract
CD69 C-type lectin receptor represents a functional triggering molecule on activated NK cells, capable of directing their natural killing function. The receptor-proximal signaling pathways activated by CD69 cross-linking and involved in CD69-mediated cytotoxic activity are still poorly understood. Here we show that CD69 engagement leads to the rapid and selective activation of the tyrosine kinase Syk, but not of the closely related member of the same family, ZAP70, in IL-2-activated human NK cells. Our results indicate the requirement for Src family kinases in the CD69-triggered activation of Syk and suggest a role for Lck in this event. We also demonstrate that Syk and Src family tyrosine kinases control the CD69-triggered tyrosine phosphorylation and activation of phospholipase Cγ2 and the Rho family-specific exchange factor Vav1 and are responsible for CD69-triggered cytotoxicity of activated NK cells. The same CD69-activated signaling pathways are also observed in an RBL transfectant clone, constitutively expressing the receptor. These data demonstrate for the first time that the CD69 receptor functionally couples to the activation of Src family tyrosine kinases, which, by inducing Syk activation, initiate downstream signaling pathways and regulate CD69-triggered functions on human NK cells.
Dynamics of Memory T Cell Proliferation Under Conditions of Heterologous Immunity and Bystander Stimulation
Authors: Kim Sung-Kwon , Brehm Michael A. , Welsh Raymond M. , Selin Liisa K. 
Published: April 2014

Abstract
By examining adoptively transferred CSFE-labeled lymphocytic choriomeningitis virus (LCMV)-immune donor T cells in Thy-1 congenic hosts inoculated with viruses or with the cytokine inducer poly(I:C), strikingly different responses of bona fide memory T cells were found in response to different stimuli. Poly(I:C) (cytokine) stimulation caused a limited synchronized division of memory CD8 T cells specific to each of five LCMV epitopes, with no increase and sometimes a loss in number, and no change in their epitope hierarchy. Homologous LCMV infection caused more than seven divisions of T cells specific for each epitope, with dramatic increases in number and minor changes in hierarchy. Infections with the heterologous viruses Pichinde and vaccinia (VV) caused more than seven divisions and increases in number of T cells specific to some putatively cross-reactive but not other epitopes and resulted in substantial changes in the hierarchy of the LCMV-specific T cells. Hence, there can be memory T cell division without proliferation (i.e., increase in cell number) in the absence of Ag and division with proliferation in the presence of Ag from homologous or heterologous viruses. Heterologous protective immunity between viruses is not necessarily reciprocal, given that LCMV protects against VV but VV does not protect against LCMV. VV elicited proliferation of LCMV-induced CD8 and CD4 T cells, whereas LCMV did not elicit proliferation of VV-induced T cells. Thus, depending on the pathogen and the sequence of infection, a heterologous agent may selectively stimulate the memory pool in patterns consistent with heterologous immunity.
Cutting Edge: CD94/NKG2 Is Expressed on Th1 But Not Th2 Cells and Costimulates Th1 Effector Functions
Authors: Meyers Jennifer Hartt , Ryu Akemi , Monney Laurent , Nguyen Khuong , Greenfield Edward A. , Freeman Gordon J. , Kuchroo Vijay K. 
Published: April 2014

AbstractTh1 and Th2 cells can be phenotypically distinguished by very few cell surface markers. To identify cell surface molecules that are specifically expressed on Th1 cells, we have generated a panel of mAbs that specifically bind the surfaces of murine Th1 but not Th2 cells. One of these Abs identified the NK cell receptor CD94 as a molecule also specifically expressed on the surface of Th1 cells. As in NK cells, CD94 is expressed on Th1 cells together with members of the NKG2 family of molecules, including NKG2A, C, and E. Cross-linking these receptors on differentiated Th1 cells in vitro costimulates proliferation and cytokine production with a potency similar to that obtained by cross-linking CD28. We propose that CD94/NKG2 heterodimers may costimulate effector functions of differentiated Th1 cells.
Cutting Edge: Molecular Analysis of the Negative Regulatory Function of Lymphocyte Activation Gene-3
Authors: Workman Creg J. , Dugger Kari J. , Vignali Dario A. A. 
Published: April 2014

Abstract
Lymphocyte activation gene (LAG)-3 (CD223) is a CD4-related activation-induced cell surface molecule that binds to MHC class II molecules with high affinity and negatively regulates T cell expansion and homeostasis. In this study, we show that LAG-3 inhibits CD4-dependent, but not CD4-independent, T cell function via its cytoplasmic domain. Although high affinity interaction with MHC class II molecules is essential for LAG-3 function, tailless LAG-3 does not compete with CD4 for ligand binding. A single lysine residue (K468) within a conserved “KIEELE” motif is essential for interaction with downstream signaling molecules. These data provide insight into the mechanism of action of this important T cell regulatory molecule.
Cutting Edge: Inhibiting Measles Virus Infection but Promoting Reproduction: An Explanation for Splicing and Tissue-Specific Expression of CD46
Authors: Riley Rebecca C. , Tannenbaum Pamela L. , Abbott David H. , Atkinson John P. 
Published: April 2014

Abstract
Membrane cofactor protein (MCP; CD46) regulates the complement cascade by inhibiting C3b and C4b deposited on self tissue. This function resides in the complement control protein repeats (CCPs), with CCPs 2–4 essential for regulation. MCP is expressed on the inner acrosomal membrane of human sperm, and Abs to CCP1 inhibit sperm-egg interactions. In somatic tissues, New World monkeys express an alternatively spliced form of MCP lacking CCP1. Although retaining complement-regulatory activity, this form is postulated to render these species less susceptible to strains of the measles virus whose hemagglutinin requires CCP1 and CCP2 for attachment. Using PCR, sequencing, Western blotting, and immunohistochemistry, we characterized MCP expression in the testes and sperm of two New World monkeys. In these species, sperm express MCP bearing CCP1. The germ cell-specific expression pattern of this domain strongly suggests an evolutionarily conserved role for MCP in fertilization.
Transfer of Central Nervous System Autoantigens and Presentation in Secondary Lymphoid Organs
Authors: de Vos Alex F. , van Meurs Marjan , Brok Herbert P. , Boven Leonie A. , Hintzen Rogier Q. , van der Valk Paul , Ravid Rivka , Rensing Susanne , Boon Louis , Hart Bert A. ’t , Laman Jon D. 
Published: April 2014

AbstractDendritic cells are thought to regulate tolerance induction vs immunization by transferring Ags and peripheral signals to draining lymph nodes (LN). However, whether myelin Ag transfer and presentation in LN occurs during demyelinating brain disease is unknown. In this study, we demonstrate redistribution of autoantigens from brain lesions to cervical LN in monkey experimental autoimmune encephalomyelitis (EAE) and in multiple sclerosis (MS). Immunohistochemical analysis revealed significantly more cells containing myelin Ags in cervical LN of monkeys with EAE compared with those of healthy control monkeys. Myelin Ags were observed in cells expressing dendritic cell/macrophage-specific markers, MHC class II, and costimulatory molecules. Moreover, these cells were directly juxtaposed to T cells, suggesting that cognate interactions between myelin-containing APC and T cells are taking place in brain-draining LN. Indeed, myelin Ag-reactive T cells were observed in cervical LN from marmosets and rhesus monkeys. Importantly, these findings were paralleled by our findings in human tissue. We observed significantly more myelin Ag-containing cells in LN of individuals with MS compared with those of control individuals. These cells expressed APC markers, as observed in marmosets and rhesus monkeys. These findings suggest that during MS and EAE, modulation of T cell reactivity against brain-derived Ags also takes place in cervical LN and not necessarily inside the brain. A major implication is that novel therapeutic strategies may be targeted to peripheral events, thereby circumventing the blood-brain barrier.
Functional Activity of Natural Antibody is Altered in Cr2-Deficient Mice
Authors: Reid Russell R. , Woodcock Sean , Shimabukuro-Vornhagen Alexander , Austen William G. , Kobzik Lester , Zhang Ming , Hechtman Herbert B. , Moore Francis D. , Carroll Michael C. 
Published: April 2014

AbstractThe major source of natural IgM Abs are B-1 cells, which differ from conventional B cells in their anatomic location, cell surface phenotype, restricted usage of particular VH genes and limited use of N-region addition during V-D-J rearrangement. The origin of B-1 cells is unclear. However, they are capable of self-renewal and their development is sensitive to signaling via the B cell receptor, as genetic defects that impair the strength of the signal often result in limited development. These findings suggest that B-1 cells require either an intrinsic signal, or contact with Ag, for positive selection and expansion and/or maintenance in the periphery. In support of interaction with cognate Ag, deficiency in the complement receptors CD21/CD35 results in a 30–40% decrease in the CD5+ B-1 population. To determine whether this reduction reflects a loss of certain specificities or simply a proportional decline in the repertoire, we examined peritoneal B cells isolated from Cr2+ and Cr2def mice for recognition of a B-1 cell Ag, i.e., phosphatidylcholine, and assayed for injury in an IgM natural Ab-dependent model of reperfusion injury. We found a similar frequency of phosphatidylcholine-specific CD5+ B-1 cells in the two strains of mice. By contrast, the Cr2def mice have reduced injury in the IgM-dependent model of reperfusion injury. Reconstitution of the deficient mice with pooled IgM or adoptive transfer of Cr2+ peritoneal B cells restored injury. These results suggest that complement receptors CD21/CD35 are important in maintenance of the B-1 cell repertoire to some, but not all, specificities.
Evidence That SHIP-1 Contributes to Phosphatidylinositol 3,4,5-Trisphosphate Metabolism in T Lymphocytes and Can Regulate Novel Phosphoinositide 3-Kinase Effectors
Authors: Freeburn Robin W. , Wright Karen L. , Burgess Steven J. , Astoul Emmanuelle , Cantrell Doreen A. , Ward Stephen G. 
Published: April 2014

AbstractThe leukemic T cell line Jurkat is deficient in protein expression of the lipid phosphatases Src homology 2 domain containing inositol polyphosphate phosphatase (SHIP) and phosphatase and tensin homolog deleted on chromosome ten (PTEN). We examined whether the lack of expression of SHIP-1 and PTEN is shared by other leukemic T cell lines and PBLs. Analysis of a range of cell lines and PBLs revealed that unlike Jurkat cells, two other well-characterized T cell lines, namely CEM and MOLT-4 cells, expressed the 5′-phosphatase SHIP at the protein level. However, the 3-phosphatase PTEN was not expressed by CEM or MOLT-4 cells or Jurkat cells. The HUT78 cell line and PBLs expressed both SHIP and PTEN. Jurkat cells exhibited high basal levels of phosphatidylinositol 3,4,5-trisphosphate (PI(3,4,5)P3; the lipid substrate for both SHIP and PTEN) as well as saturated protein kinase B (PKB) phosphorylation. Lower levels of PI(3,4,5)P3 and higher levels of phosphatidylinositol 3,4-bisphosphate (PI(3,4)P2) as well as unsaturated constitutive phosphorylation of PKB were observed in CEM and MOLT-4 cells compared with Jurkat cells. In PBLs and HUT78 cells which express both PTEN and SHIP-1, there was no constitutive PI(3,4,5)P3 or PKB phosphorylation, and receptor stimuli were able to elicit robust phosphorylation of PKB. Expression of a constitutively active SHIP-1 protein in Jurkat cells was sufficient to reduce both constitutive PKB membrane localization and PKB phosphorylation. Together, these data indicate important differences between T leukemic cells as well as PBLs, regarding expression of key lipid phosphatases. This study provides the first evidence that SHIP-1 can influence the constitutive levels of PI(3,4,5)P3 and the activity of downstream phosphoinositide 3-kinase effectors in T lymphocytes.
IgE Cross-Linking or Lipopolysaccharide Treatment Induces Recruitment of Th2 Cells to the Lung in the Absence of Specific Antigen
Authors: Stephens Robin , Chaplin David D. 
Published: April 2014

AbstractWe previously showed that Th1 cells can increase recruitment of Th2 cells to the lungs even in the absence of the Th2-specific Ag. The fact that Th2 recruitment is independent from the Th2 cell Ag suggested that Th1 cells may support Th2 cell recruitment using their Ag-nonspecific proinflammatory functions. To investigate the potential for inflammatory stimuli that are distinct from Ag-specific signals to affect the recruitment of T cells, we tested whether cross-linking of IgE or treatment with LPS modulated influx of Th2 cells into the airways in the presence or absence of inhaled Ag. When naive mice that had been treated with OVA-specific Th2 cells and passively sensitized with anti-DNP IgE were challenged by intranasal administration of either DNP-haptenated OVA or DNP-BSA, increased numbers of Th2 cells were recruited to the lung compared with mice challenged intranasally with OVA alone. Intranasal administration of LPS also increased recruitment of Th2 cells to the airways. These two distinct inflammatory stimuli increased the numbers of recruited Th2 cells equally with or without concurrent challenge using the cognate Th2 Ag. This Ag-independent recruitment of Th2 cells to the lung was not associated with localization of these cells to the regional lymph nodes and was independent of Th2 cell activation. Interestingly, P- or E-selectin contributed to Th2 cell recruitment to the lung. These data suggest that Th2 cells of the adaptive immune response are similar to cells of the innate immune response in their lack of requirement for protein Ag to initiate cell recruitment. They demonstrate further that recruitment can occur independently of Ag-dependent activation.
Macrophage-Derived Complement Component C4 Can Restore Humoral Immunity in C4-Deficient Mice
Authors: Gadjeva Mihaela , Verschoor Admar , Brockman Mark A. , Jezak Heather , Shen Li Ming , Knipe David M. , Carroll Michael C. 
Published: April 2014

AbstractMice with a disrupted C4 locus (C4−/−) have an impaired immune response to thymus-dependent Ags. To test the role of bone marrow-derived C4 in humoral immunity, we reconstituted deficient animals with wild-type bone marrow or an enriched fraction of bone marrow-derived macrophages. C4 chimeras were immunized with 4-hydroxy-3-nitrophenyl5 conjugated to keyhole limpet hemocyanin (NP5- KLH) or infected with HSV-1, and the Ab response was evaluated. Wild-type bone marrow rescued the humoral immune response to both Ags, i.e., the soluble Ag and HSV-1, demonstrating that local C4 production is sufficient for humoral responses. Although the C4 chimeric animals lacked detectable C4 in their sera, C4 mRNA was identified in splenic sections by in situ hybridization, and C4 protein deposits were identified in the germinal center areas of splenic follicles by immunofluorescence staining. Macrophages derived from bone marrow produced sufficient C4 protein to restore the humoral response to NP5-KLH in C4-deficient animals when administered along with Ag. Cell-sorting experiments, followed by C4-specific RT-PCR, identified splenic macrophages (CD11b+, CD11c−) as a cellular source for C4 synthesis within the spleen.
Organ-Specific Cytokine Polarization Induced by Adoptive Transfer of Transgenic T Cells
Authors: Zhang Lei , Lizzio Elaine F. , Gubina Elena , Chen Trina , Mostowski Howard , Kozlowski Steven 
Published: April 2014

AbstractThere are two distinct phenotypes of T cell cytokine responses that lead to different effector functions and different outcomes in disease processes. Although evidence suggests a possible role of the local microenvironment in the differentiation or localization of T cells with these phenotypes, there are no examples of divergent T cell cytokine phenotypes with the same Ag specificity concurrently existing in different tissue compartments. Using a CD8+ T cell adoptive transfer model for graft-vs-host disease, we demonstrate that a potent type 2 cytokine response develops in the spleen while a potent type 1 cytokine response simultaneously develops in the testis. These experiments demonstrate for the first time that cytokine production can be oppositely polarized in different organs of the same individual. This may have important implications for organ-specific pathology in infection or autoimmunity: infections or autoimmune diseases that affect multiple organs may have heterogeneity in tissue cytokine responses that is not revealed in systemic lymphocyte cytokine responses. Therefore, attempts to modulate the immune response phenotype may ameliorate pathology in one organ while exacerbating pathology in another.
HLA-DQ Determines the Response to Exogenous Wheat Proteins: A Model of Gluten Sensitivity in Transgenic Knockout Mice
Authors: Black Kay E. , Murray Joseph A. , David Chella S. 
Published: April 2014

Abstract
We have investigated the genetic basis of the immune response to dietary gluten in HCD4/DQ8 and HCD4/DQ6 double transgenic mice. Mice were immunized with gluten i.p. or individual peptides s.c. and spleen or draining lymph node T cells were challenged in vitro. Strong proliferative responses to gluten were seen in the HCD4/DQ8 mice, whereas the HCD4/DQ6 mice responded to gluten poorly. A series of overlapping peptides spanning gliadin were synthesized. The HCD4/DQ8 mice reacted to many of the individual peptides of gliadin, while the HCD4/DQ6 mice were relatively unresponsive. T cells isolated from HCD4/DQ8 mice also responded well to modified (deamidated) versions of the gliadin peptides, whereas HCD4DQ6 mice did not. The T cell response to gluten was CD4 dependent and DQ restricted and led to the production of cytokines IL-6, TGF-β, and IL-10. Finally, intestinal lymphocytes isolated from gluten-fed HCD4/DQ8 mice displayed an activated phenotype. These data suggest that this HLA class II transgenic murine model of gluten sensitivity may provide insight into the initiation of the MHC class II-restricted gluten sensitivity in celiac disease.
The Adjuvant Effects ofMycobacterium tuberculosisHeat Shock Protein 70 Result from the Rapid and Prolonged Activation of Antigen-Specific CD8+ T Cells In Vivo
Authors: Harmala Lisa A. E. , Ingulli Elizabeth G. , Curtsinger Julie M. , Lucido Michelle M. , Schmidt Clint S. , Weigel Brenda J. , Blazar Bruce R. , Mescher Matthew F. , Pennell Christopher A. 
Published: April 2014

AbstractHeat shock protein 70 (hsp70) is a potent adjuvant that links innate and adaptive immune responses. To study how hsp70 activates naive CD8+ T cells in vivo, we tracked Ag-specific CD8+ T cells in mice immunized with a fusion protein containing chicken OVA linked to hsp70 derived from Mycobacterium tuberculosis (OVA.TBhsp70). On a molar basis, OVA.TBhsp70 was several hundred times more effective than OVA peptide plus CFA in eliciting specific CD8+ T cell responses. Immunization with OVA.TBhsp70 activated &gt;90% of detectable OVA-specific CD8+ T cells within 3 days and led to the persistence of cytotoxic effectors for at least 17 days. These studies demonstrate that the potent adjuvant effect of M. tuberculosis hsp70 results from the relatively complete, rapid, and durable activation of Ag-specific CD8+ T cells.
Dendritic Cell-Associated Lectin-1: A Novel Dendritic Cell-Associated, C-Type Lectin-Like Molecule Enhances T Cell Secretion of IL-4
Authors: Ryan Elizabeth J. , Marshall Aaron J. , Magaletti Dario , Floyd Helen , Draves Kevin E. , Olson N. Eric , Clark Edward A. 
Published: April 2014

AbstractWe have characterized dendritic cell (DC)-associated lectin-1 (DCAL-1), a novel, type II, transmembrane, C-type lectin-like protein. DCAL-1 has restricted expression in hemopoietic cells, in particular, DCs and B cells, but T cells and monocytes do not express it. The DCAL-1 locus is within a cluster of C-type lectin-like loci on human chromosome 12p12–13 just 3′ to the CD69 locus. The consensus sequence of the DCAL-1 gene was confirmed by RACE-PCR; however, based on sequence alignment with genomic DNA and with various human expressed sequence tags, we predict that DCAL-1 has two splice variants. C-type lectins share a common sequence motif of 14 invariable and 18 highly conserved aa residues known as the carbohydrate recognition domain. DCAL-1, however, is missing three of the cysteine residues required to form the standard carbohydrate recognition domain. DCAL-1 mRNA and protein expression are increased upon the differentiation of monocytes to CD1a+ DCs. B cells also express high levels of DCAL-1 on their cell surface. Using a DCAL-1 fusion protein we identified a population of CD4+ CD45RA+ T cells that express DCAL-1 ligand. Coincubation with soluble DCAL-1 enhanced the proliferation of CD4+ T cells in response to CD3 ligation and significantly increased IL-4 secretion. In contrast, coincubation with soluble DC-specific ICAM-3-grabbing nonintegrin (CD209) fusion protein as a control had no effect on CD4+ T cell proliferation or IL-4 and IFN-γ secretion. Therefore, the function of DCAL-1 on DCs and B cells may act as a T cell costimulatory molecule, which skews CD4+ T cells toward a Th2 response by enhancing their secretion of IL-4.