Biomedical subjects

Mary Collins

Publications and source records attributed to Mary Collins.

At least 19 recordsLinked to original sources

PubMed2006

PD-1/PD-L1, but not PD-1/PD-L2, interactions regulate the severity of experimental autoimmune encephalomyelitis.

Interactions between PD-1 and its two differentially expressed ligands, PD-L1 and PD-L2, attenuate T cell activation and effector function. To determine the role of these molecules in autoimmune disease of the CNS, PD-1-/-, PD-L1-/- and PD-L2-/- mice were generated and immunized to induce experimental autoimmune encephalomyelitis (EAE). PD-1-/- and PD-L1-/- mice developed more severe EAE than wild type and PD-L2-/- mice. Consistent with this, PD-1-/- and PD-L1-/- cells produced elevated levels of the pro-inflammatory cytokines IFN-gamma, TNF, IL-6 and IL-17. These results demonstrate that interactions between PD-1/PD-L1, but not PD-1/PDL-2, are crucial in attenuating T cell responses in EAE.

Animals↗

PubMed2006

Optimization of a myeloid cell transfusion strategy for infected neutropenic hosts.

Although granulocyte transfusion is a logical, therapeutic option for neutropenic patients with refractory infections, significant technical barriers have prevented its widespread use. A novel phagocyte transfusion strategy has been developed based on activation of a human myeloid cell line HL-60. To further define the potential for HL-60 cells to recapitulate white cell transfusions, a shortened duration of activation was evaluated, facile quality control markers were defined, and the impact of low-dose irradiation on cell function was determined. Three days of activation resulted in increased cell viability and in vitro candidacidal capacity but with slightly higher cell replication compared with 7 days of activation. Cell viability and several flow cytometric measurements were accurate, quality control markers for HL-60 activation. In combination with activation, low-dose irradiation abrogated replication while sparing the candidacidal effects of the HL-60 cells. Infusion of irradiated, activated HL-60 cells improved survival of neutropenic, candidemic mice significantly. In summary, activated, irradiated HL-60 cells are microbicidal, have virtually no replicative capacity, and are safe and effective at protecting neutropenic mice against an otherwise 100% fatal candidal infection. With continued development, this strategy to recapitulate neutrophil functions has the potential to serve as an effective alternative to granulocyte transfusions.

Animals↗

PubMed2006

Interleukin (IL)-22 and IL-17 are coexpressed by Th17 cells and cooperatively enhance expression of antimicrobial peptides.

Th17 cells are a distinct lineage of effector CD4(+) T cells characterized by their production of interleukin (IL)-17. We demonstrate that Th17 cells also expressed IL-22, an IL-10 family member, at substantially higher amounts than T helper (Th)1 or Th2 cells. Similar to IL-17A, IL-22 expression was initiated by transforming growth factor beta signaling in the context of IL-6 and other proinflammatory cytokines. The subsequent expansion of IL-22-producing cells was dependent on IL-23. We further demonstrate that IL-22 was coexpressed in vitro and in vivo with both IL-17A and IL-17F. To study a functional relationship among these cytokines, we examined the expression of antimicrobial peptides by primary keratinocytes treated with combinations of IL-22, IL-17A, and IL-17F. IL-22 in conjunction with IL-17A or IL-17F synergistically induced the expression of beta-defensin 2 and S100A9 and additively enhanced the expression of S100A7 and S100A8. Collectively, we have identified IL-22 as a new cytokine expressed by Th17 cells that synergizes with IL-17A or IL-17F to regulate genes associated with skin innate immunity.

Animals↗

PubMed2006

The IL-21 receptor augments Th2 effector function and alternative macrophage activation.

The IL-21 receptor (IL-21R) shows significant homology with the IL-4R, and CD4+ Th2 cells are an important source of IL-21. Here we examined whether the IL-21R regulates the development of Th2 responses in vivo. To do this, we infected IL-21R-/- mice with the Th2-inducing pathogens Schistosoma mansoni and Nippostrongylus brasiliensis and examined the influence of IL-21R deficiency on the development of Th2-dependent pathology. We showed that granulomatous inflammation and liver fibrosis were significantly reduced in S. mansoni-infected IL-21R-/- mice and in IL-21R+/+ mice treated with soluble IL-21R-Fc (sIL-21R-Fc). The impaired granulomatous response was also associated with a marked reduction in Th2 cytokine expression and function, as evidenced by the attenuated IL-4, IL-13, AMCase, Ym1, and FIZZ1 (also referred to as RELMalpha) responses in the tissues. A similarly impaired Th2 response was observed following N. brasiliensis infection. In vitro, IL-21 significantly augmented IL-4Ralpha and IL-13Ralpha1 expression in macrophages, resulting in increased FIZZ1 mRNA and arginase-1 activity following stimulation with IL-4 and IL-13. As such, these data identify the IL-21R as an important amplifier of alternative macrophage activation. Collectively, these results illustrate an essential function for the IL-21R in the development of pathogen-induced Th2 responses, which may have relevance in therapies for both inflammatory and chronic fibrotic diseases.

Animals↗

PubMed2006

Autoreactive T cells mediate NK cell degeneration in autoimmune disease.

Emerging evidence indicates that NK cells play an important and complex role in autoimmune disease. Humans with autoimmune diseases often have reduced NK cell numbers and compromised NK cell functions. Mechanisms underlying this NK cell degeneration and its biological significance are not known. In this study we show that, in an experimental model of human autoimmune myasthenia gravis induced by a self-Ag, the acetylcholine receptor, NK cells undergo proliferation during the initiation of autoimmunity, followed by significant degeneration associated with the establishment of the autoreactive T cell response. We show that NK cell degeneration was mediated by IL-21 derived from autoreactive CD4(+) T cells, and that acetylcholine receptor-immunized IL-21R-deficient mice, with competent NK cells, developed exacerbated autoimmunity. Thus, NK cell degeneration may serve as a means evolved by the immune system to control excessive autoimmunity.

Animals↗

PubMed2006

Cell-surface and cytokine biomarkers in autoimmune and inflammatory diseases.

Increasing emphasis is being placed on biomarkers as indicators of disease states in patients with autoimmune and inflammatory disorders, such as rheumatoid arthritis, multiple sclerosis and systemic lupus erythematosus. Careful description of the expression of cell-surface markers and cytokines produced by T and B lymphocytes can lead to a more complete characterization of disease activity in patient populations, and serve as an indicator of the patient's response to therapy.

Anti-Inflammatory Agents↗

PubMed2005

DNA vaccines encoding retrovirus-based virus-like particles induce efficient immune responses without adjuvant.

Virus-like particle (VLP)-based vaccines have provided highly encouraging results in clinical trials while, in contrast, DNA vaccines expressing non-particulate proteins have proven less successful. Seeking to combine the immunogenicity of VLPs and the ease of production of plasmid DNA, we designed DNA vaccines expressing VLPs consisting of the MLV Gag and modified MLV Env proteins displaying T cell epitopes. We show here that such DNA vaccines are remarkably efficient immunogens for inducing cellular immune responses. In contrast to similar plasmids harboring a point mutation preventing VLP formation, they induce protection against a lethal viral challenge in mice. Thus, these "plasmo-retroVLPs" represent a promising second-generation DNA vaccine.

Adjuvants, Immunologic↗

PubMed2005

Lentiviral vector expression of tumour antigens in dendritic cells as an immunotherapeutic strategy.

Therapeutic cancer vaccines need to stimulate a refractory immune system to make an effective anti-tumour response. We have explored the use of lentiviral vectors to deliver tumour antigen genes to dendritic cells (DC) as a possible mechanism of immune stimulation. Direct injection of a lentiviral vector encoding the melanoma antigen NY-ESO-1 in HLA-A2 transgenic mice primed NY-ESO-1-specific CD8+ cells that could be expanded by boosting with an NY-ESO-1 vaccinia virus. The expanded cells could kill NY-ESO-1(157-165) peptide-pulsed targets in vivo. In order to examine the priming step directly, we constructed another lentiviral vector expressing the melanoma antigen Melan-A (MART-1). Here we show that Melan-A protein is also efficiently expressed after transduction of human DC cultured from peripheral blood mononuclear cells. When these transduced DC are co-cultured with autologous naïve T cells, they cause the expansion of cells that recognise the HLA-A2 restricted Melan-A(27-35) epitope. The expanded cells are functional in that they release IFN-gamma upon antigen stimulation. Melan-A lentiviral vector transduced DC caused a similar level of naïve T-cell expansion to Melan-A(27-35) peptide-pulsed DC in four experiments using different HLA-A2 positive donors. These data suggest that a vaccine based either on DC transduced with a lentiviral vector ex vivo, or on direct lentiviral vector injection, should be assessed in a phase I clinical trial.

Animals↗

PubMed2005

Nurse case management improves blood pressure, emotional distress and diabetes complication screening.

We studied the impact of nurse case management (NCM) on blood pressure (BP), hemoglobin A1C, lipids, and diabetes complication screening. A 1-year randomized-controlled trial was conducted in two primary care clinics of the Penn State Hershey Medical Center. Diabetes patients were randomized to control group (CG) (n=182) who received usual care by their primary care provider and intervention group (IG) (n=150) who received additional NCM care, including self-management education, and implementation of diabetes guidelines. Primary outcomes included BP, A1C, lipid, process measures, and secondary outcome was diabetes-related emotional distress as assessed by Problem Areas in Diabetes (PAID). BP significantly decreased from 137/77 to 129/72 in IG as compared to an increase from 136/77 to 138/79 in CG after 1 year. PAID scores improved significantly in IG (from 23 to 10) due to reduced emotional stress. A1C (7.4) and LDL (105) were unaffected. Complications screening significantly improved in IG compared to CG: opthalmologic exam 26 to 68%, foot exam 47 to 64%, and nephropathy screening 34 to 72%. NCM improved BP, diabetes-related emotional distress, and process measures in primary care. Unchanged A1C and lipids might be due to a threshold effect. Intervention based upon initial risk assessment may prove more cost-effective.

Aged↗

PubMed2005

B-cell depletion inhibits arthritis in a collagen-induced arthritis (CIA) model, but does not adversely affect humoral responses in a respiratory syncytial virus (RSV) vaccination model.

We report the development of a mouse B cell-depleting immunoconjugate (anti-CD22 monoclonal antibody [mAb] conjugated to calicheamicin) and its in vivo use to characterize the kinetics of CD22+ B-cell depletion and reconstitution in murine primary and secondary lymphoid tissues. The effect of B-cell depletion was further studied in a murine collagen-induced arthritis (CIA) model and a respiratory syncytial virus (RSV) vaccination model. Our results show that (1) the immunoconjugate has B-cell-specific in vitro and in vivo cytotoxicity; (2) B-cell reconstitution starts in the bone marrow and spleen around day 30 after depletion and is completed in all tissues tested by day 50; (3) B-cell depletion inhibits the development of clinical and histologic arthritis in the CIA model; (4) depletion of type II collagen antibody levels is not necessary for clinical and histologic prevention of CIA; and (5) B-cell depletion does not adversely affect memory antibody responses after challenge nor clearance of infectious virus from lungs in the RSV vaccination model. These results demonstrate for the first time that only B-cell reduction but not type II collagen antibody levels correlate with the prevention of arthritis and represent key insights into the role of CD22-targeted B-cell depletion in mouse autoimmunity and vaccination models.

Animals↗

PubMed2005

Specific T regulatory cells display broad suppressive functions against experimental allergic encephalomyelitis upon activation with cognate antigen.

To date, very few Ag-based regimens have been defined that could expand T regulatory (Treg) cells to reverse autoimmunity. Additional understanding of Treg function with respect to specificity and broad suppression should help overcome these limitations. Ig-proteolipid protein (PLP)1, an Ig carrying a PLP1 peptide corresponding to amino acid residues 139-151 of PLP, displayed potent tolerogenic functions and proved effective against experimental allergic encephalomyelitis (EAE). In this study, we took advantage of the Ig-PLP1 system and the PLP1-specific TCR transgenic 5B6 mouse to define a regimen that could expand Ag-specific Treg cells in vivo and tested for effectiveness against autoimmunity involving diverse T cell specificities. The findings indicate that in vivo exposure to aggregated Ig-PLP1 drives PLP1-specific 5B6 TCR transgenic cells to evolve as Treg cells expressing CD25, CTLA-4, and Foxp3 and producing IL-10. These Treg cells were able to suppress PLP1 peptide-induced EAE in both SJL/J and F(1) (SJL/J x C57BL/6) mice. However, despite being effective against disease induced with a CNS homogenate, the Treg cells were unable to counter EAE induced by a myelin basic protein or a myelin oligodendrocyte glycoprotein peptide. Nevertheless, activation with Ag before transfer into the host mice supports suppression of both myelin oligodendrocyte glycoprotein- and myelin basic protein peptide-induced EAE. Thus, it is suggested that activation of Treg cells by the cognate autoantigen is necessary for operation of broad suppressive functions.

Amino Acid Sequence↗

PubMed2005

The B7 family of immune-regulatory ligands.

The B7 family consists of structurally related, cell-surface protein ligands, which bind to receptors on lymphocytes that regulate immune responses. Activation of T and B lymphocytes is initiated by engagement of cell-surface, antigen-specific T-cell receptors or B-cell receptors, but additional signals delivered simultaneously by B7 ligands determine the ultimate immune response. These 'costimulatory' or 'coinhibitory' signals are delivered by B7 ligands through the CD28 family of receptors on lymphocytes. Interaction of B7-family members with costimulatory receptors augments immune responses, and interaction with coinhibitory receptors attenuates immune responses. There are currently seven known members of the family: B7.1 (CD80), B7.2 (CD86), inducible costimulator ligand (ICOS-L), programmed death-1 ligand (PD-L1), programmed death-2 ligand (PD-L2), B7-H3, and B7-H4. Members of the family have been characterized predominantly in humans and mice, but some members are also found in birds. They share 20-40% amino-acid identity and are structurally related, with the extracellular domain containing tandem domains related to variable and constant immunoglobulin domains. B7 ligands are expressed in lymphoid and non-lymphoid tissues. The importance of the family in regulating immune responses is shown by the development of immunodeficiency and autoimmune diseases in mice with mutations in B7-family genes. Manipulation of the signals delivered by B7 ligands has shown potential in the treatment of autoimmunity, inflammatory diseases and cancer.

Animals↗

PubMed2005

A phagocytic cell line markedly improves survival of infected neutropenic mice.

Disseminated candidiasis is a frequent infection in neutropenic patients, in whom it causes 50% mortality, despite antifungal therapy. As the duration of neutropenia is the strongest predictor of survival in neutropenic patients with invasive fungal infections, neutrophil transfusions are a logical, therapeutic option. However, significant technical barriers have prevented the clinical use of neutrophil transfusions. To overcome these barriers, we identified a human phagocytic cell line that could be administered to candidemic hosts in lieu of freshly harvested neutrophils. HL-60 cells killed Candida albicans in vitro. Activation of HL-60 cells with dimethyl sulfoxide and retinoic acid abrogated the cells' proliferation and augmented their killing of C. albicans. Administration of activated HL-60 cells to candidemic, neutropenic mice significantly improved survival (53% vs. 0%). Live HL-60 cells chemotaxed to sites of infection, phagocytized C. albicans, and reduced the fungal burden in key target organs. Although unactivated HL-60 cells also reduced tissue fungal burden in vivo, they did not improve survival as a result of their toxicity in infected mice. In contrast, no toxicity as a result of activated HL-60 cells was observed at up to 2 months of follow-up. To our knowledge, this is the first description of a cell line-based immunotherapy for an infectious disease. With further refinements, activated HL-60 cells have the potential to overcome the technical barriers to neutrophil transfusions.

Analgesics, Non-Narcotic↗

PubMed2005

IL-21 effects on human IgE production in response to IL-4 or IL-13.

In human atopic disease, IgE sensitizes the allergic response, while IgG4 is protective. Because IL-4 and IL-13 trigger switch recombination to both IgE and IgG4, additional agents must regulate the balance between these isotypes to influence susceptibility or tolerance to atopy. In this report, we define in vitro conditions leading to activation or inhibition of human IgE and IgG4 production by IL-21. IL-21 reduced IL-4-driven IgE synthesis by mitogen-stimulated human PBMC. IL-21 inhibition of human IgE production was not a direct effect on B cells, was not seen following B cell activation with IL-13, and was overcome by CD40 ligation. Neither IFN-gamma, IL-10, IL-12, CD40L expression, nor apoptosis was responsible for the inhibitory effect. In contrast, IL-21-stimulated secretion of IgG4 from PBMC. Our findings indicate that IL-21 may influence the production of both human IgE and IgG4, and thus contribute to the regulation of atopic reactions.

Antibodies, Monoclonal↗

PubMed2005

Therapeutic opportunities in the B7/CD28 family of ligands and receptors.

The CD28 and B7 protein families are critical regulators of immune responses and, in the past few years, several new family members have been identified. Preclinical studies exploring the role of members of the CD28 and B7 families support the targeting of these pathways for new therapeutic approaches. Indeed, recent Phase I clinical studies using agonists and antagonists of the CD28/CTLA-4/B7 pathway have shown promise in inflammatory diseases and cancer.

Animals↗

PubMed2005

Gene transfer to repopulating human CD34+ cells using amphotropic-, GALV-, or RD114-pseudotyped HIV-1-based vectors from stable producer cells.

A novel, stable human immunodeficiency virus type 1 vector packaging system, STAR, was tested for its ability to transduce human cord blood CD34+ progenitor cells assayed both in vitro and after transplantation into NOD/SCID mice. Vectors pseudotyped with three different gammaretrovirus envelopes were used: the amphotropic MLV envelope (MLV-A), a modified gibbon ape leukemia virus envelope (GALV+), and a modified feline endogenous virus RD114 envelope (RDpro). Gene transfer to freshly thawed CD34+ cells in the absence of cytokines was very low. Addition of cytokines increased gene transfer efficiency significantly and this was further augmented if the cells were prestimulated for 24 h. Concentration of the vectors (15-fold) by low-speed centrifugation increased gene transfer to CD34+ cells in vitro even further. More than 90% of cells were transduced with a single exposure to the RDpro vector as determined by GFP expression using flow cytometry. The two other pseudotypes transduced approximately 65-70% of the cells under the same conditions. Transplantation of CD34+ cells prestimulated for 24 h and then transduced with a single exposure to concentrated vector revealed that the RDpro vector transduced 55.1% of NOD/SCID repopulating human cells, which was significantly higher than the MLV-A (12.6%)- or GALV+ (25.1%)-pseudotyped vectors.

Animals↗

PubMed2005

Pilot evaluation of citalopram for the treatment of hot flashes in women with inadequate benefit from venlafaxine.

BACKGROUND: While newer antidepressants, such as venlafaxine and paroxetine, substantially decrease hot flashes, there is no published information with regards to whether a different antidepressant will be effective when one antidepressant does not adequately relieve hot flashes. OBJECTIVE: The objective of this trial was to provide pilot information with regards to whether citalopram would effectively reduce hot flashes in patients who did not receive adequate enough hot flash reduction with venlafaxine. DESIGN: This was a prospective pilot trial. MEASUREMENTS: Validated patient-completed hot flash diary questionnaires were utilized for measuring hot flashes. SUBJECTS: Thirty patients were recruited to this trial, 22 of whom were fully evaluable. RESULTS: Compared to a baseline week, hot flash scores were reduced by 53% 4 weeks later. The citalopram appeared to be well tolerated with many quality-of-life and potential toxicity symptoms much improved compared to the baseline week. At the end of the 4-week treatment, 19 patients (63% of patients entering the study and 86% of the patient completing the study treatment) chose to continue to use citalopram. CONCLUSION: This pilot information supports the hypothesis that citalopram will reduce hot flashes in patients with inadequate hot flash relief while taking venlafaxine.

Adult↗

PubMed2005

Conjugation of lentivirus to paramagnetic particles via nonviral proteins allows efficient concentration and infection of primary acute myeloid leukemia cells.

Nonviral producer cell proteins incorporated into retroviral vector surfaces profoundly influence infectivity and in vivo half-life. We report the purification and concentration of lentiviral vectors using these surface proteins as an efficient gene transduction strategy. Biotinylation of these proteins and streptavidin paramagnetic particle concentration enhances titer 400- to 2,500-fold (to 10(9) CFU/ml for vesicular stomatitis virus G protein and 5 x 10(8) for amphotropic murine leukemia virus envelope). This method also uses newly introduced membrane proteins (B7.1 and DeltaLNGFR) directed to lentiviral surfaces, allowing up to 17,000-fold concentrations. Particle conjugation of lentivirus allows facile manipulation in vitro, resulting in the transduction of 48 to 94% of human acute myeloid leukemia blasts.

Cell Line↗