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Papers by Andrea J Tenner

To characterize macrophage gene expression profiles during the uptake of autologous apoptotic cel... more To characterize macrophage gene expression profiles during the uptake of autologous apoptotic cells, we developed a unique, more physiologic system using primary human monocyte derived macrophages purified via a nonactivating isolation procedure (and in the absence of contaminating platelets, which can release stimulating signals if activated) and autologous lymphocytes as a source of apoptotic cells. The use of autologous cells as the apoptotic target rather than transformed cell lines avoids antigenic stimulation from " nonself " structures at the HLA level but also from " altered self " signals due to the transformation inherent in cell lines.

Chronic activation of the complement system and induced inflammation are associated with neuropat... more Chronic activation of the complement system and induced inflammation are associated with neuropathology in Alzheimer's disease (AD). Recent large genome wide association studies (GWAS) have identified single nucleotide polymorphisms (SNPs) in the C3b/C4b receptor (CR1 or CD35) that are associated with late onset AD. Here, anti-CR1 antibodies (Abs) directed against different epitopes of the receptor, were used to localize CR1 in brain, and relative binding affinities of the CR1 ligands, C1q and C3b, were assessed by ELISA. Most Abs tested stained red blood cells in blood vessels but showed no staining in brain paren-chyma. However, two monoclonal anti-CR1 Abs labeled astrocytes in all of the cases tested, and this reactivity was preabsorbed by purified recombinant human CR1. Human brain-derived astrocyte cultures were also reactive with both mAbs. The amount of astro-cyte staining varied among the samples, but no consistent difference was conferred by diagnosis or the GWAS-identified SNPs rs4844609 or rs6656401. Plasma levels of soluble CR1 did not correlate with diagnosis but a slight increase was observed with rs4844609 and rs6656401 SNP. There was also a modest but statistically significant increase in relative binding activity of C1q to CR1 with the rs4844609 SNP compared to CR1 without the SNP, and of C3b to CR1 in the CR1 genotypes containing the rs6656401 SNP (also associated with the larger isoform of CR1) regardless of clinical diagnosis. These results suggest that it

A complete genetic deficiency of the complement protein C1q results in SLE with nearly 100% penet... more A complete genetic deficiency of the complement protein C1q results in SLE with nearly 100% penetrance in humans, but the molecular mechanisms responsible for this association have not yet been fully determined. C1q opsonizes ACs for enhanced ingestion by phagocytes, such as Mf and iDCs, avoiding the extracellular release of inflammatory DAMPs upon loss of the membrane integrity of the dying cell. We previously showed that human monocyte-derived Mf and DCs ingesting autol-ogous, C1q-bound LALs (C1q-polarized Mf and C1q-polarized DCs), enhance the production of anti-inflammatory cytokines, and reduce proinflammatory cytokines relative to Mf or DC ingesting LAL alone. Here, we show that C1q-polarized Mf have elevated PD-L1 and PD-L2 and suppressed surface CD40, and C1q-polarized DCs have higher surface PD-L2 and less CD86 relative to Mf or DC ingesting LAL alone, respectively. In an MLR, C1q-polarized Mf reduced allogeneic and autologous Th17 and Th1 subset proliferation and demonstrated a trend toward increased Treg proliferation relative to Mf ingesting LAL alone. Moreover, relative to DC ingesting AC in the absence of C1q, C1q-polarized DCs decreased autologous Th17 and Th1 proliferation. These data demonstrate that a functional consequence of C1q-polarized Mf and DC is the regulation of Teff activation, thereby " sculpting " the adaptive immune system to avoid autoimmunity, while clearing dying cells. It is noteworthy that these studies identify novel target pathways for therapeutic intervention in SLE and other autoimmune diseases.

Peripheral blood monocytes are actively infected by Toxoplasma gondii and can function as 'Trojan... more Peripheral blood monocytes are actively infected by Toxoplasma gondii and can function as 'Trojan horses' for parasite spread in the bloodstream. Using dynamic live-cell imaging, we visualized the transendothelial migration (TEM) of T. gondii-infected primary human monocytes during the initial minutes following contact with human endothelium. On average, infected and uninfected monocytes required only 9.8 and 4.1 min, respectively , to complete TEM. Infection increased monocyte crawling distances and velocities on endothelium, but overall TEM frequencies were comparable between infected and uninfected cells. In the vasculature, monocytes adhere to endothe-lium under the conditions of shear stress found in rapidly flowing blood. Remarkably, the addition of fluidic shear stress increased the TEM frequency of infected monocytes 4.5-fold compared to static conditions (to 45.2% from 10.3%). Infection led to a modest increase in expression of the high-affinity conformation of the monocyte integrin Mac-1 (CD11b/CD18), and Mac-1 accumulated near endothelial junctions during TEM. Blocking Mac-1 inhibited the crawling and TEM of infected monocytes to a greater degree than uninfected monocytes, and blocking the Mac-1 ligand, ICAM-1, dramatically reduced crawling and TEM for both populations. These findings contribute to a greater understanding of parasite dissemination from the vasculature into tissues.

The complement system is an ancient and critical ef-fector mechanism of the innate immune system ... more The complement system is an ancient and critical ef-fector mechanism of the innate immune system as it senses, kills, and clears infectious and/or dangerous particles and alerts the immune system to the presence of the infection and/or danger. Interestingly, an increasing number of reports have demonstrated a clear role for complement in the adaptive immune system as well. Of note, a number of recent studies have identified previously unknown roles for complement proteins, receptors, and regulators in T cell function. Here, we will review recent data demonstrating the influence of complement proteins C1q, C3b/iC3b, C3a (and C3aR), and C5a (and C5aR) and complement regulators DAF (CD55) and CD46 (MCP) on T cell function during homeostasis and disease. Although new concepts are beginning to emerge in the field of complement regulation of T cell function, future experiments should focus on whether complement is interacting directly with the T cell or is having an indirect effect on T cell function via APCs, the cytokine milieu, or downstream complement activation products. Importantly, the identification of the pivotal molecular pathways in the human systems will be beneficial in the translation of concepts derived from model systems to therapeutic targeting for treatment of human disorders.

Investigations of the activation processes involved in human monocytes and monocyte-derived macro... more Investigations of the activation processes involved in human monocytes and monocyte-derived macrophages and dendritic cells often required large numbers of cells that have not been possibly altered or activated by adherence to surfaces, by binding of antibodies to surface antigens during positive selection, or by release of activators by platelets or other non myeloid cells during isolation or co-culture. Human peripheral blood monocytes as well as lymphocytes from the same blood donor can be isolated by counterflow elutriation using a modification of the technique of Lionetti et al., 1980 as described previously (Bobak et al., 1986). From a unit of blood drawn into anticoagulant, 60-120 million monocytes can be obtained. These cells are not activated and have been shown to be appropriately capable of differential activation in multiple studies.

We investigated the functions of adiponectin, an adipocyte-specific secretory protein and a new m... more We investigated the functions of adiponectin, an adipocyte-specific secretory protein and a new member of the family of soluble defense collagens, in hematopoiesis and immune responses. Adiponectin suppressed colony formation from colony-forming units (CFU)-granulocytemacrophage, CFU-macrophage, and CFUgranulocyte, whereas it had no effect on that of burst-forming units-erythroid or mixed erythroid-myeloid CFU. In addition, adiponectin inhibited proliferation of 4 of 9 myeloid cell lines but did not suppress proliferation of erythroid or lymphoid cell lines except for one cell line. These results suggest that adiponectin predominantly inhibits proliferation of myelomonocytic lineage cells. At least one mechanism of the growth inhibition is induction of apoptosis because treatment of acute myelomonocytic leukemia lines with adiponectin induced the appearance of subdiploid peaks and oligonucleosomal DNA fragmentation. Aside from inhibiting growth of myelomonocytic progenitors, adiponectin suppressed mature macrophage functions. Treatment of cultured macrophages with adiponectin significantly inhibited their phagocytic activity and their lipopolysaccharide-induced production of tumor necrosis factor ␣. Suppression of phagocytosis by adiponectin is mediated by one of the complement C1q receptors, C1qRp, because this function was completely abrogated by the addition of an anti-C1qRp monoclonal antibody. These observations suggest that adiponectin is an important negative regulator in hematopoiesis and immune systems and raise the possibility that it may be involved in ending inflammatory responses through its inhibitory functions. (Blood. 2000;96: 1723-1732)

Molecular Immunology, 2000

Human C1qR P is a highly glycosylated transmembrane protein that is the human C1q receptor/recept... more Human C1qR P is a highly glycosylated transmembrane protein that is the human C1q receptor/receptor component that in vitro mediates enhancement of Fc-and C3b-mediated phagocytosis. A human genomic clone and a murine genomic clone that is 73% identical in sequence with the coding region for human C1qR P cDNA have been isolated. Chromosomal localization of the human and murine gene demonstrates that these genes are syntenic. Murine cell lines of diverse myeloid origins are shown to respond to interaction of C1q with the enhancement of phagocytosis similar to that seen previously in human peripheral blood monocytes. Northern blot, RT-PCR, Western blot and FACS analyses demonstrated that mC1qR P is expressed in these murine myeloid cell lines, but not in a mouse epithelial cell line, similar to the cell type expression of the human gene product. A polyclonal antibody to a peptide sequence common to the deduced sequence from the both murine and human C1qR P inhibited the enhancement of phagocytosis response to C1q when cells were permeabilized to permit access of the antibody to the intracellular milieu. These data support the postulate that the identified murine and human genes are homologs, confirm the previously predicted intracellular location of the C-terminus of the molecule, and indicates the necessary role of this intracellular domain in transducing the signal that leads to enhancement of phagocytic function.

Molecular Immunology, 2000