RNA-loaded CD40-activated B cells stimulate antigen-specific T-cell responses in dogs with spontaneous lymphoma.

Cell-based vaccination strategies to induce functional tumor-specific T cells in cancer patients have focused on using autologous dendritic cells. An alternative approach is to use RNA-loaded CD40 activated B cells (CD40-B) that are highly efficient antigen-presenting cells capable of priming naive T cells, boosting memory T-cell responses and breaking tolerance to tumor antigens. The use of tumor RNA as the antigenic payload allows for gene transfer without viruses or vectors and permits major histocompatibility complex (MHC)-independent, multiple-antigen targeting. Here, we use CD40L transfected K562 cells to generate functional CD40-B cells from the peripheral blood of humans and dogs. Testing of RNA-loaded CD40-B cells in dogs allows not only for its development in veterinary medicine but also for determination of its safety and efficacy in a large animal model of spontaneous cancer prior to initiation of human clinical trials. We found that CD40-B cells from healthy humans, healthy dogs and tumor-bearing dogs express increased levels of immune molecules such as MHC and CCR7. Moreover, RNA-loaded CD40-B cells induce functional, antigen-specific T cells from healthy dogs and dogs with lymphoma. These findings pave the way for immunotherapy trials using tumor RNA-loaded CD40-B cells to stimulate antitumor immunity in a large animal model of spontaneous neoplasia.

Mouse oocytes regulate granulosa cell steroidogenesis.

Recent studies have demonstrated a critical role for the oocyte in proliferation and differentiation of granulosa cells and expansion of the cumulus oophorus in vitro. The purpose of this study was to determine if steroid production by cumulus granulosa cells was also modulated by oocytes. Mouse oocyte-cumulus cell complexes (intact) and complexes from which the oocytes were removed microsurgically (oocytectomized; OOX) were cultured for 24 h in the presence or absence of follicle-stimulating hormone (FSH; 150 ng/ml), testosterone (T; 5 x 10(-7) M) or both. Oocytectomy had no effect on the ability of cumulus cells to produce progesterone or estradiol in control cultures or in response to T. However, OOX complexes produced 17- and 36-fold more progesterone than intact complexes when cultured in the presence of FSH or FSH+T, respectively. Oocyte-conditioned medium (maximum 1 oocyte/2 microliters) had no effect on progesterone production by intact cumulus complexes, but reduced the progesterone production by OOX complexes by 75%. This inhibition was directly proportional to the number of oocytes used to condition the medium. Oocytectomy caused a slight decrease (29%) in estradiol production by complexes in the presence of FSH and T; however, OOX complexes in oocyte-conditioned medium produced almost twice as much estradiol as complexes in unconditioned medium. These results indicate that mouse oocytes secrete a factor(s) that inhibits progesterone and stimulates estradiol production by cumulus granulosa cells.

The effect of consecutive day inseminations on semen characteristics in an intrauterine insemination program.

This study demonstrates a statistically significant decrease in semen volume, sperm concentration, and sperm motility in samples obtained on the 2nd day of consecutive day inseminations in an IUI program. This diminution in semen characteristics persists despite sperm washing. The effects of a second ejaculation on semen parameters in oligospermic and asthenospermic men were mixed. Thus, in general, sperm-washing procedures cannot overcome the natural reduction in semen quality produced by frequent ejaculations. Clinicians may wish to use this information in timing IUI cycle inseminations.