Utility of a C57BL/6 ES line versus 129 ES lines for Targeted Mutations in Mice

Inbred ES lines, though useful for generating targeted mutations in mice, are used infrequently. To appreciate the relative efficiency of inbred ES lines, a C57BL/6 ES line was compared with 129 strain ES lines for effectiveness in chimera formation leading to the establishment of targeted mutations in mice. Data from a transgenic facility spanning 7 years were collected. C57BL/6 ES cells injected into Balb/c embryos results in lower coat color chimerism than do 129 ES cells injected into C57BL/6 embryos. Combined data indicate that five independent targeted C57BL/6 clones should be injected as compared to three independent 129 clones to generate enough chimeras to effectively test for germ-line transmission. Thus, although less efficient than 129 ES lines, the C57BL/6 ES line is a relatively competent line and useful for the routine generation of targeted mutations in mice on a defined genetic background.     

Intraperitoneal delivery of human natural killer cells for treatment of ovarian cancer in a mouse xenograft model

Background aimsThere is an urgent need for novel therapeutic strategies for relapsed ovarian cancer. Dramatic clinical anti-tumor effects have been observed with interleukin (IL)-2 activated natural killer (NK) cells; however, intravenous delivery of NK cells in patients with ovarian cancer has not been successful in ameliorating disease. We investigated in vivo engraftment of intraperitoneally (IP) delivered NK cells in an ovarian cancer xenograft model to determine if delivery mode can affect tumor cell killing and circumvent lack of NK cell expansion.MethodsAn ovarian cancer xenograft mouse model was established to evaluate efficacy of IP-delivered NK cells. Tumor burden was monitored by bioluminescent imaging of luciferase-expressing ovarian cancer cells. NK cell persistence, tumor burden and NK cell trafficking were evaluated. Transplanted NK cells were evaluated by flow cytometry and cytotoxicity assays.ResultsIP delivery of human NK cells plus cytokines led to high levels of circulating NK and was effective in clearing intraperitoneal ovarian cancer burden in xenografted mice. NK cells remained within the peritoneal cavity 54 days after injection and had markers of maturation. Additionally, surviving NK cells were able to kill ovarian cancer cells at a rate similar to pre-infusion levels, supporting that in vivo functionality of human NK cells can be maintained after IP infusion.ConclusionsIP delivery of NK cells leads to stable engraftment and antitumor response in an ovarian cancer xenograft model. These data support further pre-clinical and clinical evaluation of IP delivery of allogeneic NK cells in ovarian cancer.     

Course of heavy primary infections and earlier immunologically mediated rejection of secondary infections of Hymenolepis diminuta in mice

Roepstorff A. and Andreassen J. 1982. Course of heavy primary infections and earlier immunologically mediated rejection of secondary infections of Hymenolepis diminuta in mice. International Journal for Parasitology12: 23–28. The worms of heavy (50–100 worms) primary Hymenolepis diminuta infections in inbred C57-mice were 1–2 mm long when growth ceased about day 4. Thereafter the mean length decreased by shrinkage and/or ‘decollation’, the worms moved backwards in the small intestine and were rejected from day 6 to day 10. Heavy secondary infections given 14 days after a heavy primary infection were severely stunted (0.2–0.3 mm) but normally situated in the intestine on day 2 and nearly all were rejected by day 4. Even when the time between the primary and secondary infections was increased to 21 or 42 days, therecovery, position and length of the secondary worms were significantly different from primary infections. These results show that an immunologically mediated memory was involved, and that functional antigens can be released from the scolex and/or the neck alone.     

Reformation in chimeric antigen receptor based cancer immunotherapy: Redirecting natural killer cell

Natural killer (NK) cells are an important subset of lymphocytes which play a critical role in host immunity against cancers. With MHC-independent recognition, short lifespan and potent cytotoxicity, NK cells make a promising candidate for chimeric antigen receptor (CAR)-engineered cancer immunotherapy. Due to innate biological properties of NK cells, CAR-NK may outperform CAR-T therapy in terms of less side effects and more universal access, which may become a great reformation in CAR-based cancer immunotherapy. The CARs used in peripheral blood (PB) NK cells as well as NK cell line like NK-92 are the most important outfits defining antigenic specificity. The constructs of CARs used in NK cells from different sources vary, which all undergo generational optimization. The anti-tumor effects of CAR-NK have been validated in numerous preclinical trials for cancers, including hematologic malignancies and many solid tumors, which provide evidence for potential clinical application of CAR-NK. Additionally, this review concludes the challenges faced in the application of CAR-NK. Although CAR-NK is considered as one of the most possible “off-the-shelf” products, the improvement for the efficiency of expansion and transduction as well as the solution for underlying safety issues is still needed. Possible coping strategies for challenges and upgrades in techniques are also highlighted for future development in CAR-NK cancer immunotherapy.     

Toxoplasma gondii: an evaluation of diagnostic value of recombinant antigens in a murine model

Laboratory diagnostics of toxoplasmosis depends primarily on serological methods detecting specific antibodies. Since these methods do not always enable specific and sensitive recognition of the infection and phase of toxoplasmosis, the search for new diagnostic tools continues. Recombinant antigens promise a new alternative in diagnostics of Toxoplasma gondii infections. In this work the usefulness of six recombinant T. gondii antigens: GRA1, GRA6, GRA7, p35, SAG1, and SAG2 in the detection of primary murine toxoplasmosis was evaluated. Sera obtained from infected mice differing in their natural susceptibility to T. gondii infection, BALB/c (relatively resistant) and C57BL/6 (relatively susceptible), were tested using ELISA. During acute infection high response to GRA7, GRA6, and p35 antigens was noticed, whereas a strong reactivity with surface antigens SAG1 and SAG2 was characteristic for chronic toxoplasmosis. Our results show that the recombinant antigens are useful in distinguishing between acute and chronic toxoplasmosis regardless of the genetically determined susceptibility of the host.