Highly efficient redirected anti-tumor activity of human lymphocytes transduced with a completely human chimeric immune receptor

BACKGROUND: Novel antibody-based immunotherapeutic strategies exploit chimeric immune receptors (CIR), expressed on the surface of transduced human peripheral blood mononuclear cells (PBMC), to redirect potent non-MHC-dependent cytotoxicity to tumor cells expressing a tumor-associated antigen. However, clinical application of the strategy has been hampered by the potential side effects associated with immunogenicity and by low transduction efficiency. METHODS: A fully human CIR was constructed that triggers immune activation through the zeta chain of CD3 and contains a human single-chain antibody fragment specific for an extracellular epitope of HER2. PBMC were transduced with the CIR using gibbon-ape leukemia virus envelope pseudotyped retroviruses. In vitro cytotoxicity and inhibition assays were carried out using normal and tumor cell lines expressing different levels of HER2. RESULTS: Bulk populations of CIR-transduced PBMC could express high levels of the construct and subcloning ensured stable expression. CIR-mediated killing and growth inhibition of targets expressing high HER2 levels were very efficient at low effector-to-target ratios. Under the same experimental conditions, CIR-mediated activity against normal cells expressing low HER2 levels was marginal. The CIR-mediated recognition of target cells induced the release of soluble factors able to inhibit growth of both HER-positive and HER2-negative bystander tumor cells. CONCLUSIONS: Human CIR-transduced PBMC exert a potent and dose-dependent anti-tumor activity. Target antigen level appeared to be a critical determinant of specificity and delivery of signals leading to redirected effector functions. Soluble factors, released by redirected effectors at the site of antigen-driven activation, mediate potent bystander killing.     

Characterization of oxylipins and dioxygenase genes in the asexual fungus Aspergillus niger

Background  

Aspergillus niger is an ascomycetous fungus that is known to reproduce through asexual spores, only. Interestingly, recent genome analysis of A. niger has revealed the presence of a full complement of functional genes related to sexual reproduction [1]. An example of such genes are the dioxygenase genes which in Aspergillus nidulans, have been shown to be connected to oxylipin production and regulation of both sexual and asexual sporulation [2–4]. Nevertheless, the presence of sex related genes alone does not confirm sexual sporulation in A. niger.