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Complement activation contributes to the expression of local and remote organ injury in animal models of ischemia-reperfusion (IR). We demonstrate here that a soluble form of decay-accelerating factor (DAF) protects normal C57Bl/6 and autoimmunity-prone B6.MRL/lpr mice subjected to hindlimb IR from remote intestinal and lung injury without affecting the degree of local skeletal muscle injury. In addition, DAF treatment attenuates remote organ injury in mice subjected to mesenteric IR. Soluble DAF allowed the deposition of complement 3 in local and remote injury sites while it limited the presence of terminal membrane attack complex and did not increase animal susceptibility to sepsis. These data provide evidence that soluble DAF might offer clinical benefit to patients suffering remote intestinal or lung damage in response to muscle or other organ injury.

Regulatory T cells (T Reg ), CD4 + CD25 + FOXP3 + , are implicated in suppressing tumor immune responses. We analyzed peripheral blood lymphocytes (PBL) from breast cancer patients receiving a modified HLA class II HER2/ neu peptide (AE37) vaccine for T Reg cells and correlated their levels with vaccine-specific immune responses. The mean CD4 + CD25 + FOXP3 + T Reg cells decreased in patients with vaccination with no significant difference in serum TGF-β levels. IFN-γ ELISPOT and DTH increased after vaccination with a good correlation between T Reg cell reduction and size of DTH to AE37. The T Reg cell reduction and associated immune response suggest that AE37 may be clinically useful.

Elements of the innate and adaptive immune response have been implicated in the development of tissue damage after ischemic reperfusion (I/R). Here we demonstrate that T cells infiltrate the intestine of C57BL/6 mice subjected to intestinal I/R during the first hour of reperfusion. The intensity of the T cell infiltration was higher in B6.MRL/lpr mice subjected to intestinal I/R and reflected more severe tissue damage than that observed in control mice. Depletion of T cells limited I/R damage in B6.MRL/lpr mice, whereas repletion of B6.MRL/lpr lymph node-derived T cells into the I/R-resistant Rag-1−/− mouse reconstituted tissue injury. The tissue-infiltrating T cells were found to produce IL-17. Finally, IL-23 deficient mice, which are known not to produce IL-17, displayed significantly less intestinal damage when subjected to I/R. Our data assign T cells a major role in intestinal I/R damage by virtue of producing the pro-inflammatory cytokine IL-17.

Natural Abs and autoantibodies bind antigens displayed by ischemia-conditioned tissues, followed by complement activation and enhanced tissue injury during reperfusion. Anti-ribonucleoprotein (RNP) Ab is associated with lung disease in patients with autoimmune disease but it is not known whether these abs contribute to lung injury. Mesenteric I/R in mice leads to local and remote lung injury. Accordingly, we used this model to investigate whether anti-RNP Abs would reconstitute I/R damage with prominent lung damage in injury-resistant Rag1(-/-) animals. Rag1(-/-) mice injected with anti-RNP Ab containing serum and subjected to mesenteric I/R suffered greater intestinal injury than control-treated and sham-operated animals. The magnitude of the reconstituted damage was anti-RNP Ab titer-dependent. Anti-RNP Ab-treated animals demonstrated a dose-dependent increase in lung histologic injury scores compared to control and sham animals. Anti-RNP mediated injury was shown to be complement dependent. These experiments reveal a novel mechanism whereby anti-RNP Abs contributes to the development of pulmonary pathology in patients with autoimmune diseases following exposure of remote organs to I/R injury.

Introduction: We are conducting a Phase II clinical trial of 2 HER2 peptide vaccines, GP2 (MHC Class I restricted) and AE37 (MHC Class II restricted), for the prevention of breast cancer (BCa) recurrence in disease-free, high risk patients (pts). We present analysis of T cell populations in trial patients at the time of enrollment and differences based on time since chemotherapy. We describe a “reconstitution” of the immune system after immunosuppressive chemotherapy. Methods: After completion of standard therapy, disease-free, BCa pts were enrolled. Demographic data was collected. Blood was collected prior to administration of their first vaccine. Peripheral blood mononuclear cells from 50 pts were isolated and evaluated for CD8+, CD4+CD8+, CD4-CD8- and CD4+ T cell populations. T cell proliferation responses were measured in patients of both arms of the trial; generically with FluM-specific CD8 cells (HLA-A2:Ig dimer assay) in the GP2 arm (n=58), and then with proliferation response to AE36 and AE37 in the AE37 arm (n=85). Linear regression analyses evaluated the relationship between time from chemotherapy and each T cell population. Immune responses of pts enrolled less than one year from chemotherapy (1yr group) using a t-test. Results: Chemotherapy regimens were determined by the treating oncologist and consisted primarily of anthracycline-based regimens with a taxane. Regression analysis revealed a significant correlation between time from chemotherapy and both CD4+ and CD8+ Tcell counts (R= .433, p=0.015 and R=.439, p=.014, respectively). Total T cell, CD4-CD8- and CD4+CD8+ populations, however, did not significantly correlate with increased time from chemotherapy (R=.28, p=0.128, R=.068, p=.715 and R=.058, p=.755, repectively). Comparison between the 1yr group in the GP2 arm (n=43 and n=15) for FluM-specific CD8 cells revealed a non-significant increase in immune response in the >1yr group (2.74 vs 3.57, p=0.15). A similar comparison in the AE37 arm (n=56 1yr) revealed increased proliferation in the >1yr group (AE36: 1110 vs 2167, p=0.034, AE37: 983 vs 2179, p=0.001). There were no significant differences between the >1yr and Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-130. doi:1538-7445.AM2012-LB-130

Introduction: The affinity between tumor-associated antigens and MHC Class I complexes directly affects the degree of CD8+ T cell (CTL) response. GP2 (IISAVVGIL, p654-662) is a HER2/neu-derived peptide, that has poor binding affinity to HLA-A2 (A2) and HLA-A3 (A3). We conducted a preclinical study to determine if amino acid substitutions in the GP2 peptide, predicted to increase binding affinity to A2 and A3, enhance CTL recognition and stimulation. Methods: Based on computer modeling algorithms (BIMAS, SYFPEITHI), two GP2 peptide variants were predicted to have higher binding affinity to A2: SPA-12(2L9V-GP2) and SPA-13(2L5L9V-GP2). Freshly isolated PBMCs were obtained from randomly chosen, disease-free, node positive (NP) and high risk node negative (NN) breast cancer (BCa) patients, who had completed standard adjuvant therapy and are enrolled in the E75 vaccine booster trial. Peptide-specific CD8+ T cells were measured by HLA-A2: IgG dimer (A2 pts) and by interferon-γ ELISPOT (A2, A3 pts) assays. Groups were compared by t-test (dimer) and Mann-Whitney U (ELISPOT) tests. Results: Thirty-five A2 (21 NP, 14 NN) and thirteen A3 (13 NP) samples were included in the study. Among A2 pts, the mean level of SPA-12-specific CTLs was greater than the GP2- (2.8±0.3% vs. 1.7±0.1%, p Conclusion: The substituted sequences SPA-12 (2L9V-GP2) and SPA-13 (2L5L9V-GP2), both have higher predicted binding affinity to A2 and A3 than GP2. While SPA-12 showed significantly increased recognition and functional CTL responses compared to GP2, SPA-13 demonstrated lower responses. These data suggest that SPA-12 may be a more effective cancer vaccine than GP2, particularly in NP BCa patients. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-322.