| Abstrakt: |
Although several murine macrophage (mφ)cell lines from different sites have previously been obtained by in vitro infection with the J2 murine retrovirus, which carries the v‐rafand v‐myc oncogenes, it was not possible to immortalize thioglycolate‐elicited peritoneal macrophages (Pmφs) by this in vitro procedure. A technique utilizing in vivo injection of the J2 virus has been developed to overcome this problem. The J2 virus immortalized Pm φsin a very efficient manner in vivo because no exogenous growth factors were required for the in vitro proliferation of these cells and numerous continuous cloned cell lines were readily established. In contrast, Pmφs obtained from uninfected mice or Pmφs infected in vitro with the J2 virus did not proliferate. The in vivo immortalized cells had many of the morphological and functional characteristics of mφs. Analysis of two of the clones, PMJ2‐PC and PMJ2‐R, demonstrated intracellular expression of the product of the v‐raf gene, presence of mφ‐associated cell surface antigens, interleukin‐6 secretion induced by lipopolysaccharide, and biological response modifier‐induced cytotoxic activity against tumor cells. In addition, one of the clones, PMJ2‐PC, constitutively expressed major histocompatibility complex (MHC) class II antigens, and in the other clone, PMJ2‐R, MHC class II antigen expression was induced by recombinant murine interferon‐γ. This method of utilizing the J2 virus in vivo represents a novel technique for obtaining hematopoietic cell lines from cells that are difficult to immortalize in vitra |
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