Stimulation Of Peripheral Blood Mononuclear Cells Research Articles

Immunological behavior of in vitro digested egg‐white lysozyme

Besides its antimicrobial properties, lysozyme (LYS) is one of the major allergens from hen egg. This paper addresses the identification of the peptides produced upon in vitro gastrointestinal digestion of LYS, together with their IgE-binding and biological activity as a contribution to the understanding of what makes it a relevant allergen. Simulated in vitro gastrointestinal digestion together with IgE binding, basophil degranulation, and peripheral blood mononuclear cells stimulation experiments were carried out. Identification of the fragments released was performed by HPLC-MS/MS and the immunoreactive products were analyzed by MALDI-TOF/TOF. Results showed that in vitro gastric and gastroduodenal digests of LYS maintained IgE binding, basophil activation capacity, and preserved T-cell immunogenicity. These biological activities could be attributed to either the persistence of intact LYS, due to incomplete gastric degradation and subsequent duodenal precipitation, the formation of fragment f(24-129) by chymotrypsin action on the soluble intact protein, or the release, upon combined gastric and pancreatic digestion, of immunoreactive peptides linked by disulphide bonds containing the epitopes f(57-83) and f(108-122). The pH of gastric hydrolysis greatly determined the extent of subsequent duodenal digestion of LYS and the disclosure of relevant epitopes that could increase its allergenic potential.

Increased telomere length and proliferative potential in peripheral blood mononuclear cells of adults of different ages stimulated with concanavalin A

BackgroundRecently, a direct correlation with telomere length, proliferative potential and telomerase activity has been found in the process of aging in peripheral blood cells. The objective of the study was to evaluate telomere length and proliferative potential in peripheral blood mononuclear cells (PBMCs) after stimulation with Concanavalin A (ConA) of young adults compared with older adults.MethodsBlood samples were obtained from 20 healthy young males (20–25 years old) (group Y) and 20 males (60–65 years old) (group O). We compared PBMC proliferation before and after stimulation with ConA. DNA was isolated from cells separated before and after culture with ConA for telomeric measurement by real-time polymerase chain reaction.ResultsIn vitro stimulation of PBMCs from young subjects induced an increase of telomere length as well as a higher replicative capacity of cell proliferation. Samples from older adults showed higher loss of telomeric DNA (p = 0.03) and higher levels of senescent (≤6.2 kb) telomeric DNA (p = 0.02) and displayed a marked decrease of proliferation capacity. Viability cell counts and CFSE tracking in 72-h-old cell cultures indicated that group O PBMCs (CD8+ and CD4+ T cells) underwent fewer mitotic cycles and had shorter telomeres than group Y (p = 0.04).ConclusionsOur findings confirm that telomere length in older-age adults is shorter than in younger subjects. After stimulation with ConA, cells are not restored to the previous telomere length and undergo replicative senescence. This is in sharp contrast to the response observed in young adults after ConA stimulation where cells increase in telomere length and replicative capacity. The mechanisms involved in this phenomenon are not yet clear and merit further investigation.

Effects of short-term sitagliptin treatment on immune parameters in healthy individuals, a randomized placebo-controlled study

Sitagliptin, a dipeptidyl-peptidase 4 (DPP-4) inhibitor, improves blood glucose control in patients with type 2 diabetes by blocking cleavage of glucagon-like peptide 1 (GLP-1). In type 2 diabetes patients sitagliptin use is associated with an increase in minor infections, and in new-onset type 1 diabetes patients the ability of sitagliptin to dampen autoimmunity is currently being tested. DPP-4, also known as CD26, is expressed on leucocytes and can inactivate many chemokines important for leucocyte migration, as well as act as a co-stimulatory molecule on T cells. Therefore, this study was conducted to test whether sitagliptin is immunomodulatory. In this randomized, placebo-controlled trial, healthy volunteers were given sitagliptin or placebo daily for 28 days, and blood was drawn for immune assays. No significant differences were observed in the percentage of leucocyte subsets within peripheral blood mononuclear cells (PBMCs), plasma chemokine/cytokine levels or cytokines released by stimulation of PBMCs with either lipopolysaccharide (LPS) or anti-CD3. Individuals taking sitagliptin displayed increases in the percentage of cells expressing higher levels of CD26 at early time-points compared to placebo controls, but these differences resolved by day 28 of treatment. Therefore, in healthy volunteers, treatment with sitagliptin daily for 28 days does not overtly alter systemic immune function.

Identification of Promiscuous KIF20A Long Peptides Bearing Both CD4+ and CD8+ T-cell Epitopes: KIF20A-Specific CD4+ T-cell Immunity in Patients with Malignant Tumor

To identify long peptides (LP) derived from a novel tumor-associated antigen (TAA), kinesin family member 20A (KIF20A), which induce tumor-specific T-helper type 1 (TH1) cells and CTLs. We combined information from a recently developed computer algorithm predicting HLA class II-binding peptides with KIF20A-derived CTL-epitope sequences presented by HLA-A2 (A*02:01) or HLA-A24 (A*24:02) to select candidate promiscuous TH1-cell epitopes containing CTL epitopes. Peripheral blood mononuclear cells (PBMC) derived from healthy donors or patients with head-and-neck malignant tumor (HNMT) were used to study the immunogenicity of KIF20A-LPs, and the in vitro cross-priming potential of KIF20A-LPs bearing CTL epitopes. We used HLA-A24 transgenic mice to address whether vaccination with KIF20A-LP induces efficient cross-priming of CTLs in vivo. The TH1-cell response to KIF20A-LPs in HNMT patients receiving immunotherapy with TAA-derived CTL-epitope peptides was analyzed using IFN-γ enzyme-linked immunospot assays. We identified promiscuous KIF20A-LPs bearing naturally processed epitopes recognized by CD4(+) T cells and CTLs. KIF20A-specific CTLs were induced by vaccination with a KIF20A-LP in vivo. KIF20A expression was detected in 55% of HNMT by immunohistochemistry, and significant frequencies of KIF20A-specific TH1 cell responses were detected after short-term in vitro stimulation of PBMCs with KIF20A-LPs in 50% of HNMT patients, but not in healthy donors. Furthermore, these responses were associated with KIF20A expression in HNMT tissues. These are the first results showing the presence of KIF20A-specific TH1 cell responses in HNMT patients and underline the possible utility of KIF20A-LPs for propagation of TH1 cells and CTLs.

Hemorrhagic shock and resuscitation are associated with peripheral blood mononuclear cell mitochondrial dysfunction and immunosuppression

Trauma and hypovolemic shock are associated with mitochondrial dysfunction and septic complications. We hypothesize that hypovolemic shock and resuscitation results in peripheral blood mononuclear cell (PBMC) mitochondrial dysfunction that is linked to immunosuppression. With the use of a decompensated shock model, Long-Evans rats were bled to a mean arterial pressure of 40 mm Hg until the blood pressure could no longer be maintained without fluid infusion. Shock was sustained by incremental infusion of lactated Ringer's solution until 40% of the shed volume had been returned (severe shock). Animals were resuscitated with four times the shed volume in lactated Ringer's solution over 60 minutes (resuscitation). Control animals underwent line placement but were not hemorrhaged. Animals were randomized to control (n = 5), severe shock (n = 5), or resuscitation (n = 6) groups. At each time point, PBMC were isolated for mitochondrial function analysis using flow cytometry and high-resolution respirometry. Immune function was evaluated by quantifying serum interleukin 6 (IL-6) and tumor necrosis factor (TNF-α) after PBMC stimulation with lipopolysaccharide. The impact of plasma on mitochondrial function was evaluated by incubating PBMCs harvested following severe shock with control plasma. PBMCs from control animals were likewise mixed with plasma collected following resuscitation. Student's t test and Pearson correlations were performed (significance, p < 0.05). Following resuscitation, PBMCs demonstrated significant bioenergetic failure with a marked decrease in basal, maximal, and adenosine triphosphate-linked respiration. Mitochondrial membrane potential also decreased significantly by 50% following resuscitation. Serum IL-6 increased, while lipopolysaccharide stimulated TNF-α production decreased dramatically following shock and resuscitation. Observed mitochondrial dysfunction correlated significantly with IL-6 and TNF-α levels. PBMCs demonstrated significant mitochondrial recovery when incubated in control serum, whereas control PBMCs developed depressed function when incubated with serum collected following severe shock. Mitochondrial dysfunction following hemorrhagic shock and resuscitation was associated with the inhibition of PBMC response to endotoxin that may lead to an immunosuppressed state.

Stimulation of human peripheral blood mononuclear cells by the sialic acid precursor N-propanoylmannosamine

N-Propanoylmannosamine is an unnatural precursor of sialic acid, which is taken up by a variety of animal cells and metabolized to N-propanoylneuraminic acid. In several studies it has been demonstrated that application of unnatural precursors of sialic acids such as N-propanoylmannosamine (ManNProp) and homologues interfere with cell differentiation and proliferation of neuronal cells or embryonic stem cells. Since the function of the immune system is known to rely on the presence of sialic acid, we applied ManNProp to human peripheral blood mononuclear cells (PBMC). When culturing those lymphocytes with ManNProp 10 % of the natural sialic acid N-acetylneuraminic acid could be replaced by the newly formed N-propanoylneuraminic acid. This procedure resulted (a) in a marked stimulation in the rate of proliferation of PBMC, (b) a 10-fold increase of IL-2 production coupled with an up-regulation of its receptor CD25 on the cell surface and (c) a concomitant expression and regulation of the transferrin receptor with cell growth. The stimulation of PBMC by ManNProp might therefore introduce a new approach of immunomodulation.

Alterations in inflammatory, antiviral and regulatory cytokine responses in peripheral blood mononuclear cells from pregnant women with asthma

Severe asthma exacerbations during pregnancy are a common complication leading to poor health outcomes for both the mother and the baby. Asthma exacerbations are caused most frequently by respiratory viruses. A balance between antiviral and inflammatory immune responses is critical during pregnancy; the balance may be altered by asthma and respiratory virus infection. Peripheral blood mononuclear cells (PBMCs) were isolated from (i) non-pregnant healthy controls, (ii) pregnant non-asthmatics, (iii) post-partum non-asthmatics, (iv) non-pregnant asthmatics (v) pregnant asthmatics, and (vi) post-partum asthmatics. Cells were cultured in vitro with the mitogen phytohaemagglutinin or with a strain of the 2009 pandemic swine influenza. Interferon (IFN)-γ, interleukin (IL)-10 and IL-17 protein were measured from culture supernatant. Neutrophil counts were obtained in samples from pregnant and post-partum women. Following the phytohaemagglutinin stimulation of PBMCs, pregnant asthmatics had significantly higher IL-17 and significantly lower IFN-γ responses compared with healthy non-pregnant women. Following infection with influenza, a significant reduction was also observed in IFN-γ and IL-10 production from PBMC of pregnant asthmatics. The IL-17 response to phytohaemagglutinin correlated with the neutrophil percentage. Differences in IFN-γ, IL-10 and IL-17 were found to persist for at least 6 months post-partum. A reduction in antiviral and regulatory immunity with increased inflammation during pregnancy occurs in PBMC from pregnant women with asthma. This novel information may relate to the increased susceptibility and disease severity to respiratory virus infections observed during pregnancy.

AB0143 Angiotensin receptor type 1 and endothelin receptor type a on immune cells mediate migration and the expression of il-8 and ccl18 when stimulated by autoantibodies from systemic sclerosis patients

BackgroundAgonistic autoantibodies against the angiotensin II receptor type 1 (AT1R) and the endothelin receptor type A (ETAR) have been identified in patients suffering from systemic sclerosis (SSc).ObjectivesHere we examined the...

AB0221 Estrogen modulation of endosome-associated toll-like receptors and ZAS3: An underlying mechanism of gender-BIAS in systemic lupus erythematosus?

BackgroundSystemic lupus erythematosus (SLE) is a prototypic autoimmune disease characterized by significant gender bias. Previous studies have demonstrated the contributions of hormones, particularly estrogen (E2), to SLE pathogenesis. E2 has...

Th1 and Th2 cytokine profiles induced by hepatitis C virus F protein in peripheral blood mononuclear cells from chronic hepatitis C patients

Th1 and Th2 cytokine response has been confirmed to be correlated with the pathogenesis of HCV infection. The aim of the study is to investigate the Th1 and Th2 cytokine profiles induced by HCV alternate reading frame protein (F protein) in chronic hepatitis C patients. We assessed the immune responses specific to HCV F protein in 55 chronic HCV patients. IFN-γ, IL-2, IL-4 and IL-5 secretion by peripheral blood mononuclear cells (PBMC) post F protein stimulation were compared among HCV patients and healthy donors. Finally, the associations between HCV F protein and HLA class II alleles were explored. We found that the seroprevalence of anti-F antibodies in HCV-related hepatocellular carcinoma (HCC) patients was significantly higher than that of patients without HCC, but such a significant difference in humoral immune responses to F protein was not observed in HCV 1b-infected- and non-HCV 1b-infected-patients. Additionally, the PBMC proliferation of HCC patients was significantly lower than that of patients without HCC. Furthermore, F protein stimulation of PBMCs from F-seropositive patients resulted in Th2 biased cytokine responses (significantly decreased IFN-γ and/or IL-2 and significantly increased IL-4 and/or IL-5 levels) that reportedly may contribute to HCC progression and pathogenesis. However, no significant difference in the association between HCV F protein and HLA-DRB1*0201, 0301, 0405, 1001 and HLA-DQB1*0201, 0401, 0502, 0602 was observed in this study. These findings suggest that F protein may contribute to the HCV-associated bias in Th1/Th2 responses of chronic hepatitis C patients including the progress of HCC pathogenesis.

Peripheral Blood Mononuclear Cells of Mycetoma Patients React Differently to Madurella mycetomatis Antigens than Healthy Endemic Controls

Peripheral Blood Mononuclear Cells of Mycetoma Patients React Differently to Madurella mycetomatis Antigens than Healthy Endemic Controls

Stimulation of Naïve Monocytes and PBMCs with Coagulation Proteases Results in Thrombin‐Mediated and PAR‐1‐Dependent Cytokine Release and Cell Proliferation in PBMCs Only

Protease-activated receptors (PARs) are stimulated by proteolytic cleavage of their extracellular domain. Coagulation proteases, such as FVIIa, the binary TF-FVIIa complex, free FXa, the ternary TF-FVIIa-FXa complex and thrombin, are able to stimulate PARs. Whereas the role of PARs on platelets is well known, their function in naïve monocytes and peripheral blood mononuclear cells (PBMCs) is largely unknown. This is of interest because PAR-mediated interactions of coagulation proteases with monocytes and PBMCs in diseases with an increased activation of coagulation may promote inflammation. To evaluate PAR-mediated inflammatory reactions in naïve monocytes and PBMCs stimulated with coagulation proteases. For this, PAR expression at protein and RNA level on naïve monocytes and PBMCs was evaluated with flow cytometry and RT-PCR. In addition, cytokine release (IL-1β, IL-6, IL-8, IL-10, TNF-α) in stimulated naïve and PBMC cell cultures was determined. In this study, it is demonstrated that naïve monocytes express all four PARs at the mRNA level, and PAR-1, -3 and -4 at the protein level. Stimulation of naïve monocytes with coagulation proteases did not result in alterations in PAR expression or in the induction of inflammation involved cytokines like interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-8, interleukin-10 or tumour necrosis factor-α. In contrast, stimulation of PBMCs with coagulation proteases resulted in thrombin-mediated induction of IL-1β and IL-6 cytokine production and PBMC cell proliferation in a PAR-1-dependent manner. These data demonstrate that naïve monocytes are not triggered by coagulation proteases, whereas thrombin is able to elicit pro-inflammatory events in a PAR-1-dependent manner in PBMCs.

Abstract 4738: TLR8 stimulation enhances cetuximab-mediated natural killer cell lysis of head and neck cancer cells and dendritic cell cross priming of EGFR-specific CD8+ T cells.

Abstract Background: Cetuximab is an anti-epidermal growth factor receptor (EGFR) monoclonal antibody (mAb) that prolongs survival in the treatment of head and neck cancer (HNC), but only in 10-20%. An immunological mechanism of action including natural killer (NK) cell-mediated antibody-dependent cellular cytotoxicity (ADCC) has been suggested. We investigated the effects of activating toll-like receptor (TLR)-8 to enhance activity of cetuximab-stimulated, FcγR bearing cells. Objective: To determine the capability of TLR8-stimulation to enhance the activation and function of NK cells and dendritic cells (DC) in the presence of cetuximab-coated HNC cells. Methods: Peripheral blood mononuclear cells (PBMC), NK, DC and CD8+ T cells were isolated and analyzed using 51Cr release ADCC, flow cytometry analysis, cytokine ELISA, and EGFR853-861 tetramer staining. Results: TLR8 stimulation of unfractionated PBMC led to enhanced cetuximab-mediated ADCC in healthy donors (p=0.01) and HNC patients (p&amp;lt;0.05), which was dependent on NK cells. Secretion of Th1 cytokines TNFα(p&amp;lt;0.0001), IFNγ(p&amp;lt;0.0001), and IL-12p40(p&amp;lt;0.005) was increased. NK cells in TLR8 stimulated PBMC showed higher degranulation marker CD107a expression after incubation with cetuximab-treated HNC cells (p&amp;lt;0.001). TLR8 stimulation enhanced DC maturation markers CD80, CD83, and CD86 in co-culture with NK cells and cetuximab-treated HNC cells. Stimulation of DC using TLR8 agonist plus cetuximab-activated NK cells significantly increased EGFR-specific CD8+ T cell induction, compared to either condition alone (p&amp;lt;0.01). Discussion: VTX-2337 and cetuximab combination therapy can activate innate and adaptive anti-cancer immune responses. Further investigation in human trials will be important for determining the clinical benefit from this combination, and for determining biomarkers of response. Citation Format: Ryan M. Stephenson, Chwee Ming Lim, Maura Matthews, Gregory Dietsch, Robert Hershberg, Robert L. Ferris. TLR8 stimulation enhances cetuximab-mediated natural killer cell lysis of head and neck cancer cells and dendritic cell cross priming of EGFR-specific CD8+ T cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4738. doi:10.1158/1538-7445.AM2013-4738

Mycobacterium bovis Δmce2 double deletion mutant protects cattle against challenge with virulent M. bovis

A Mycobacterium bovis strain deleted in mce2A and mce2B genes (M. bovis Δmce2) was tested as an experimental vaccine in cattle challenged with a virulent M. bovis strain. Three-and-a-half-month old calves (n = 5 to 6 per group) were vaccinated and challenged with a virulent strain of M. bovis by the intratracheal route 9 weeks after vaccination. A non-vaccinated group and a group vaccinated with BCG were included as controls. Blood samples were collected to measure IFN-γ by an interferon-gamma release assay (IGRA), cytometry and cytokine responses of bovine purified protein derivative (PPD) restimulated peripheral blood mononuclear cells (PBMCs). The IGRA test showed IFN-γ values similar to pre-vaccination except for the animals vaccinated with M. bovis Δmce2, where a significant increase was observed at 30 days post-vaccination. The expression of IL-2R on CD4(+) cells in response to PPD from the animals vaccinated with Δmce2 increased at 15 days post-vaccination compared to cells from non-vaccinated group. Vaccination of cattle with M. bovis Δmce2 induced the highest (P < 0.05) expression of IFN-γ and IL-17 mRNA upon PPD stimulation of PBMCs compared to vaccination with BCG or that for the non-vaccinated group. There was a weak positive correlation between the production of these proinflammatory cytokines post-vaccination and reduced pathology scores post-challenge. The animals were euthanized and necropsied 100 days after challenge. The group vaccinated with M. bovis Δmce2 displayed a significantly lower histopathological score for lesions in lungs and pulmonary lymph nodes than for the other groups (P < 0.05). A marked positive reaction to tuberculin intradermal test was observed post-vaccination in animals vaccinated with M. bovis Δmce2 compared to those vaccinated with BCG or the non-vaccinated group. In contrast, after challenge, non-vaccinated animals had greater skin test responses than the vaccinated animals. In summary, M. bovis Δmce2 is a promising vaccine candidate to control M. bovis pathogenesis in cattle.

Comparison of TNFα responses induced by Toll-like receptor ligands and probiotic Enterococcus faecium in whole blood and peripheral blood mononuclear cells of healthy dogs

The assessment of in vitro responses of blood-derived cells has traditionally been performed with peripheral blood mononuclear cells (PBMCs). However, stimulation of whole blood (WB) has advantages: ease of experimental setup, avoidance of blood cell manipulation and lower assay cost and time. WB stimulation is widely used in human research, but only infrequently in small animals. The aim of this study was to compare the response generated in canine WB and PBMCs with Toll-like receptor ligands and probiotic bacteria using TNFα as measured endpoint. WB and PBMCs were derived from a total of 15 healthy dogs. Stimulations were performed with LPS (1ngml−1), Pam3CSK4 (100ngml−1), flagellin (1μgml−1) and Enterococcus faecium (EF; 1×107cfuml−1). In 4 of the dogs, PBMC numbers were matched to the numbers of PBMCs found in WB. TNFα was detected in supernatants via ELISA. TNFα production from WB was generally higher than from PBMCs (repeated measures ANOVA p<0.0128). PBMCs produced TNFα inconsistently for all stimulants apart from EF. There was no correlation between results of WB or PBMC stimulation, similar to studies that found that humanWB cytokine production correlates with stimulating monocytes, but not PBMCs. In conclusion, WB stimulation should be considered a valid alternative to PBMC stimulation in the canine system.

Elevated Serum and Synovial Fluid Levels of Interleukin-34 in Rheumatoid Arthritis: Possible Association with Disease Progression via Interleukin-17 Production

To measure the levels of interleukin-34 (IL-34) in serum and synovial fluid (SF) of patients with rheumatoid arthritis (RA) and to evaluate the effect of recombination human (rh) IL-34 on IL-17 production by peripheral blood mononuclear cells (PBMC) in RA patients, the serum and SF levels of IL-34, and the production of IL-17 by rhIL-34-treated PBMC of RA patients were measured by enzyme-linked immunosorbent assay. We also tested the change of IL-34 level after tumor necrosis factor (TNF)-α blockade therapy in 30 RA patients. In contrast to almost no detectable IL-34 in osteoarthritis (OA) and healthy serum, IL-34 could be detected in 93 out of the 125 RA cases (74.4%). Sera IL-34 levels were significantly higher in RA patients compared with the controls and correlated with disease activity. IL-34 levels were higher in SF samples than in sera in 11 RA patients. The level of serum IL-34 decreased after anti-TNF treatment. In the presence of rhIL-34, stimulation of PBMC from RA patients resulted in increased production of IL-17. These findings suggest that IL-34 may play a role in the pathogenesis of RA.

The Effect of Synthetic C-Reactive Protein on the In Vitro Immune Response of Human PBMCs Stimulated with Bacterial Reagents

Synthetic C-reactive protein (CRP) rescues mice from lethal endotoxin shock or bacterial infection by suppressing tumor necrosis factor (TNF-α), but in turn, enhances Kupffer cell phagocytic activity. We herein assessed the influence of CRP in human peripheral blood mononuclear cells (PBMCs). When human PBMCs were stimulated in vitro with penicillin-treated Streptococcus pyogenes, bacterial DNA motifs and lipopolysaccharide with or without synthetic CRP, CRP suppressed the production of TNF-α and IL-12, but not that of IFN-γ. This was also the case for the in vitro Shwartzman reaction induced in PBMCs. CRP also decreased high-mobility group box 1 production from macrophages, which is crucial in the later phase of endotoxin/septic shock. However, CRP upregulated the perforin expression by CD56+ NK cells and increased their antitumor cytotoxicity. CRP may thus be a potent immunomodulatory factor in the human immune system, suggesting its therapeutic potential for use against human septic shock.

Expression of Suppressor of Cytokine Signalling proteins (SOCS) 1 and 3 in Beh�et�s Disease

Expression of Suppressor of Cytokine Signalling proteins (SOCS) 1 and 3 in Beh�et�s Disease

Involvement of TLR7 MyD88-dependent signaling pathway in the pathogenesis of adult-onset Still's disease

IntroductionThe objective of this study was to investigate the potential role of the Toll-like receptor 7 (TLR7) signaling pathway in the pathogenesis of adult-onset Still's disease (AOSD).MethodsFrequencies of TLR7-expressing precursor of myeloid dendritic cells (pre-mDCs) and mDCs in 28 AOSD patients, 28 patients with systemic lupus erythematosus (SLE) and 12 healthy controls (HC) were determined by flow cytometry analysis. Transcript and protein levels of TLR7 signaling molecules in peripheral blood mononuclear cells (PBMCs) were evaluated by quantitative PCR and western blotting respectively. Serum cytokines levels were measured by ELISA.ResultsSignificantly higher median frequencies of TLR7-expressing pre-mDCs and mDCs were observed in AOSD patients (65.5% and 14.9%, respectively) and in SLE patients (60.3% and 14.4%, respectively) than in HC (42.8% and 8.8%, respectively; both P <0.001). Transcript and protein levels of TLR7-signaling molecules, including MyD88, TRAF6, IRAK4 and IFN-α, were upregulated in AOSD patients and SLE patients compared with those in HC. Disease activity scores were positively correlated with the frequencies of TLR7-expressing mDCs and expression levels of TLR7 signaling molecules in both AOSD and SLE patients. TLR7 ligand (imiquimod) stimulation of PBMCs resulted in significantly enhanced levels of interleukin (IL)-1β, IL-6, IL-18 and IFN-α in AOSD and SLE patients. Frequencies of TLR7-expressing mDCs and expression levels of TLR7 signaling molecules significantly decreased after effective therapy.ConclusionsElevated levels of TLR7 signaling molecules and their positive correlation with disease activity in AOSD patients suggest involvement of the TLR7 signaling pathway in the pathogenesis of this disease. The overexpression of TLR7 MyD88-dependent signaling molecules may be a common pathogenic mechanism for both AOSD and SLE.

Abstract B22: Antitumor responses driven by alloreactivity.

Abstract Previous work done by our group had found that infusion of G-CSF mobilized haploidentical donor white blood cells at a dose of 1 – 2 x 108 CD3+ cells/kg into refractory cancer patients after 100 cGy total body irradiation resulted in a number of complete and partial responses in those patients with hematological malignancies. These responses occurred despite elimination of the donor cells by 2 weeks after infusion. The effector mechanism(s) responsible for these anti-cancer responses were not determined although it was noted that there was a cytokine storm appearing within a day following infusion of the cells. Alloreactive responses could be driving the anti-cancer responses using a variety of mechanisms. One possible mechanism is that the alloreactive response overrides inhibitory mechanisms present in the cancer patient allowing the existing cancer reactive effector cells to become activated and lyse cancer cells. Alternatively the alloreactive cytolytic T cells could be cross-reacting with the antigens expressed on the tumor cells. To test these possibilities, peripheral blood mononuclear cells (PBMNC) or the CD3+ T cells isolated from the PBMNC of newly diagnosed leukemic patients were mixed with mitomycin C treated fully allogeneic stimulator PBMNC (from 1 or 2 different normal controls chosen at random) or the CD3- cells from the leukemic patients. Their ability to proliferate in response to the allogeneic stimulation was tested on day five and their ability to lyse autologous leukemia cells after stimulation was tested on day seven. Ten total patients (8 AML, 1 CML, and 1 CMML) were enrolled in the study. The average white blood cell count was 57,640 cells/uL (range 7,100 – 336,500 cells/uL) with 4 -80% peripheral blasts. The results indicated that in 16/20 combinations, leukemic T cells were able to proliferate in response to allogeneic stimulators, however anti-cancer cytolytic activity was only detected in 9/19 evaluable combinations. These results demonstrated that alloreactive responses are able to induce anti-leukemic cytolytic responses by T cells from a subset of leukemic patients. One explanation for the inability of some combinations to generate anti-leukemic cytolytic activity could be the presence of inhibitory mechanisms which could not be overcome by the alloreactive responses. Immunophenotypic analysis of the leukemic T cells did reveal an increased number of T regulatory cells and increases in the expression of inhibitory receptors on the lymphocytes from some of the patients. Alternatively, it may be that the leukemic T cells had not been stimulated with the appropriate allogeneic antigens. An allogeneic stimulator pool comprised of cells from ten different normal donors was prepared and will be used to test whether increasing the number of allogeneic disparities in culture would enhance the ability of the leukemic T cells to generate anti-leukemic responses. These studies have suggested that cancer-reactive cells can be generated from leukemic patient T cells using alloreactive responses. To further test the role of these effector cells and identify additional effector cells, blood samples will be obtained from patients enrolled in the clinical protocol which is in the process of being restarted, having received FDA approval. Clearer definition and characterization of the anti-cancer effector cells should permit alterations to the protocol that would lead to enhanced anti-cancer responses in an increased number of refractory cancer patients. Citation Format: Loren D. Fast, John Reagan, Martha Nevola, Peter Quesenberry. Antitumor responses driven by alloreactivity. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology: Multidisciplinary Science Driving Basic and Clinical Advances; Dec 2-5, 2012; Miami, FL. Philadelphia (PA): AACR; Cancer Res 2013;73(1 Suppl):Abstract nr B22.