Mouse anti-Mouse OVA peptide (257-264) bound to H-2Kb complex monoclonal antibody, clone 25-D1.16 [Biotin]

Sexed cryopreserved semen is widely used in vitro embryo production (IVEP) for cattle reproduction in Brazil. However, differences between donor breeds regarding variables related to the IVEP process have been reported. This study aimed to evaluate factors affecting the efficiency of IVEP using donors of different genotypes and sexed sperm from Gir and Holstein bulls in a commercial program of IVEP. Higher oocyte and blastocyst means per OPU session were observed in 1/2 HolsteinxGir donors. Gir donors showed higher percentage of blastocyst than Holstein donors, with blastocyst production of crossbreed donors being similar to the other breeds. Moreover, embryos in the stage of expanded blastocyst and hatching blastocyst had a higher capacity of resulting in pregnancy than embryos in the blastocyst stage. In relation to the crosses of the donor and the bull used, no effect was found on the percentage of blastocyst and pregnancy. However, donors with greater number of oocytes recovered had a higher number of blastocysts and pregnancies per OPU session. Finally, OPU sessions performed with 21-day intervals for two years did not affect the pe rformance of Gir donors on IVEP. Thus, the conclusion is that donor breed influences the rate of oocyte retrieval. Moreover, embryo production is affected by donor breed and the number of viable oocytes recovered. Only embryo developmental stage influences the pregnancy rate. Finally, bull breed does not affect IVEP results and there was no effect of repeated OPU sessions on Gir donors in these variables. These results provide new insights related to IVEP in large scale.

DNA vaccinations are promising strategies for treating diseases that require cellular immunity (i.e., cancer and protozoan infection). Here, we report on the use of a liposomal nanocarrier (lipid nanoparticles (LNPs)) composed of an SS-cleavable and pH-activated lipidlike material (ssPalm) as an in vivo DNA vaccine. After subcutaneous administration, the LNPs containing an ssPalmE, an ssPalm with vitamin E scaffolds, elicited a higher gene expression activity in comparison with the other LNPs composed of the ssPalms with different hydrophobic scaffolds. Immunization with the ssPalmE-LNPs encapsulating plasmid DNA that encodes ovalbumin (OVA, a model tumor antigen) or profilin (TgPF, a potent antigen of Toxoplasma gondii) induced substantial antitumor or antiprotozoan effects, respectively. Flow cytometry analysis of the cells that had taken up the LNPs in draining lymph nodes (dLNs) showed that the ssPalmE-LNPs were largely taken up by macrophages and a small number of dendritic cells. We found that the transient deletion of CD169(+) macrophages, a subpopulation of macrophages that play a key role in cancer immunity, unexpectedly enhanced the activity of the DNA vaccine. These data suggest that the ssPalmE-LNPs are effective DNA vaccine carriers, and a strategy for avoiding their being trapped by CD169(+) macrophages will be a promising approach for developing next-generation DNA vaccines.