When apoptotic cells are not cleared in an efficient and timely manner, they progress to secondary necrosis and lose their membrane integrity. This results in a leakage of immunostimulatory, danger associated molecular patterns (DAMPs), similar to accidental (or primary) necrosis. However, primary necrosis is a sudden event with an inadvertent release of almost unmodified DAMPs. Secondary necrotic cells, in contrast, have gone through various modifications during the process of apoptosis. Recent research revealed that the molecules released from the cytoplasm or exposed on the cell surface differ between primary necrosis, secondary necrosis, and regulated necrosis such as necroptosis. This review gives an overview of these differences and focusses their effects on the immune response. The implications to human physiology and diseases are manifold and will be discussed in the context of cancer, neurodegenerative disorders and autoimmunity.

BackgroundMonoclonal antibodies (mAb), such as trastuzumab are a valuable addition to breast cancer therapy. Data obtained from neoadjuvant settings revealed that antibody-dependent cell-mediated cytotoxicity (ADCC) is a major mechanism of action for the mAb trastuzumab. Conflicting results still call into question whether disease progression, prolonged treatment or concomitant chemotherapy influences ADCC and related immunological phenomena.MethodsWe analyzed the activity of ADCC and antibody-dependent cell-mediated phagocytosis (ADCP) of peripheral blood mononuclear cells (PBMCs) from human epidermal growth factor receptor 2 (HER2/neu) positive breast cancer patients receiving trastuzumab therapy either in an adjuvant (n = 13) or metastatic (n = 15) setting as well as from trastuzumab treatment-naive (t-naive) HER2/neu negative patients (n = 15). PBMCs from healthy volunteers (n = 24) were used as controls. ADCC and ADCP activity was correlated with the expression of antibody binding Fc-gamma receptor (FcγR)I (CD64), FcγRII (CD32) and FcγRIII (CD16) on CD14+ (monocytes) and CD56+ (NK) cells, as well as the expression of CD107a+ (LAMP-1) on CD56+ cells and the total amount of CD4+CD25+FOXP3+ (Treg) cells. In metastatic patients, markers were correlated with progression-free survival (PFS).ResultsADCC activity was significantly down regulated in metastatic, adjuvant and t-naive patient cohorts as compared to healthy controls. Reduced ADCC activity was inversely correlated with the expression of CD107a on CD56+ cells in adjuvant patients. ADCC and ADCP activity of the patient cohorts were similar, regardless of treatment duration or additional chemotherapy. PFS in metastatic patients inversely correlated with the number of peripheral Treg cells.ConclusionThe reduction of ADCC in patients as compared to healthy controls calls for adjuvant strategies, such as immune-enhancing agents, to improve the activity of trastuzumab. However, efficacy of trastuzumab-specific ADCC and ADCP appears not to be affected by treatment duration, disease progression or concomitant chemotherapy. This finding supports the application of trastuzumab at any stage of the disease.

NS1 protein of influenza virus is a virulence factor that counteracts Type I interferon (IFN)- Key words: conditionally-replicating-virus; STAT1; SCIDKnowledge of the pathogenesis of viral diseases and the ability to manipulate specific regions of viral genomes permit the construction of conditionally replicating viruses that are attenuated in normal cells but retain their ability to lyse tumor cells. [1][2][3] We show that the NS1 protein of influenza A virus is a virulence factor that counteracts the interferon (IFN)-mediated antiviral cellular response. 4 As a consequence, an influenza virus that lacks a functional NS1 protein due to an almost total deletion of the NS1 open reading frame (delNS1 virus) fails to replicate in normal cells and is apathogenic for wild-type mice. 5 The delNS1 virus, however, grows to titers similar to wild-type virus in dsRNA-activated kinase (PKR) knockout mice. 6 The conditionally replicating phenotype of the delNS1 virus in PKR-defective systems could be exploited for virally-induced oncolysis in tumors expressing oncogenic ras. 7 This observation is based on the fact that oncogenic ras inhibits PKR activation. 8 For this reason, melanoma cells became permissive for productive delNS1 virus replication upon transfection and expression of oncogenic N-ras. Moreover, delNS1 virus treatment of subcutaneous N-ras-expressing melanomas in SCID mice showed that this virus has tumor-ablative potentials in vivo.The delNS1 virus was also shown to replicate effectively in STAT1 knockout mice. 9 STAT1 exists in 2 isoforms, a 91-kD protein (STAT1␣) and a 84-kD splice variant (STAT1␤). 10 Upon activation by Type I IFN signaling STAT1 forms a heterodimer with STAT2 and becomes an essential part of the IFN-receptor induced transcription complex ISGF3. A reduced expression of STAT1 is associated with IFN resistance. 11 Alterations in the IFN-dependent signal cascades, including changes in STAT1 and Type I IFN-receptor molecules, have been described to occur frequently in malignantly transformed cells. For example, several melanoma and lymphoma cell lines contain no or reduced levels of STAT1. 12,13 In addition, leukemia cell lines were shown to be defective in IFN genes. 14 We hypothesized, therefore, that IFN resistance is a common tumor characteristic, which may allow delNS1 virus-mediated oncolysis.We analyzed the growth of delNS1 virus in IFN-resistant tumor cell lines of various histological origins. We compared the oncolytic effect of the delNS1 virus with a second virus, in which the NS1 was only deleted to the N-terminal 99 amino acids (NS1-99). In mice, the latter virus has intermediate attenuation properties ranging between delNS1 and wild-type viruses. 15 The NS1-99 virus gave us the possibility to investigate whether the attenuation level of NS1-deletion viruses influences the efficiency of oncolysis in vivo. The in vitro growth of the NS1-deletion mutants inversely correlated with the IFN resistance of the assayed cell lines. Both delNS1 and NS1-99 viruses induced a tumor-ablative ef...