Human serum-resistant retroviral vector particles from galactosyl (alpha1-3) galactosyl containing nonprimate cell lines.

Retroviral vector particles (RVP) which are resistant to inactivation by human serum will be needed for many in vivo gene therapy applications. Murine-based producer cell lines generate RVP which are inactivated by human serum, reportedly due to the presence of the galactosyl (alpha1-3) galactosyl carbohydrate moiety (alphaGal) on these and other nonprimate producer cells and RVP. Consequently, human cells (which lack the alphaGal moiety) have been developed as producer cell lines for generation of human serum-resistant RVP. In this study, we report that contrary to earlier reports, the presence of the alphaGal moiety on producer cells and RVP does not necessarily correlate with cell killing or RVP inactivation by human serum. We show that the alphaGal-positive ferret brain cell line, Mpf, is an excellent basal cell line for generation of RVP which have titers and serum resistance levels equal to or greater than RVP produced in human cell lines such as HT1080. Therefore, packaging cell lines need not be limited to those of human or primate origin for production of human serum-resistant RVP.

Vaccination with IL-2-secreting tumor cells stimulates the generation of IL-2-responsive T cells and prevents the development of unresponsiveness.

Infection of CMS5 tumor cells with retroviral constructs containing interleukin-2 (IL-2) cDNA and selection in medium supplemented with G418 resulted in the isolation of clones which secreted IL-2. Whereas injection of parental tumor cells resulted in progressive tumor growth, tumor cells secreting high levels of IL-2 were rejected. Furthermore, in animals vaccinated with IL-2-secreting cells, the immunosuppression associated with the inoculation of parental tumor cells did not develop, and these animals resisted a challenge with viable tumor cells. To better understand the functional differences in the anti-tumor responses of immune and tumor-bearing mice which are at the basis for these diverse responses, we used an in vitro model to analyze interactions between splenic lymphocytes and tumor cells. Spleen cells isolated from either tumor-bearing or immune mice proliferated vigorously when cultured alone for 6 days, but much less in the presence of parental tumor cells. This effect could not be transferred with supernatant from tumor cell lines. Spleen cells from tumor-bearing mice remained unresponsive, while those from immune mice proliferated well in response to IL-2-secreting tumor cells. Only spleen cells from immune animals were able to develop cytotoxicity against CMS5 cells following in vitro restimulation. These results are consistent with the interpretation that exposure to parental tumor cells inhibited cell-mediated anti-tumor responses by a mechanism that involved cell-to-cell contact.(ABSTRACT TRUNCATED AT 250 WORDS)

Autologous blood transfusion for major vascular surgery using the Sorenson Receptal Device.

Twenty-five patients having aortic surgery had blood scavenged using the Sorenson Receptal Device (Group A) and were compared with twenty-five patients having homologous blood transfusion (Group H). Mean intraoperative blood loss was similar in both groups, Group A 3224 (SD 2392) ml, Group H 2999 (SD 1579) ml, but the mean homologous blood replacement was significantly different intraoperatively, Group A 1.2 (SD 1.7) units, Group H 2.7 (SD 1.8) units. Total intra-hospital homologous blood replacement was not significantly different, Group A 4.0 (SD 3.4) units, Group H 5.5 (SD 5.8) units. Mean haemoglobin concentration in the scavenged blood was 8.5 (SD 2.1) g/dl compared to 10.8 (SD 2.4) g/dl in the median aged homologous blood units crossmatched for Group H. Mean red cell half life in the scavenged blood was the same as that for the homologous blood, 24 (SD 5) days, but plasma-free haemoglobin and bacterial contamination was greater in the scavenged blood. There was no difference in the incidence of postoperative renal dysfunction, coagulopathy or mortality between the two groups of patients.