Flow cytometric characterizations of leukocyte subpopulations in the peripheral blood of northern pig-tailed macaques （Macaca leonina）

Pig-tailed macaques(Macaca nemistrina group) have been extensively used as non-human primate animal models for various human diseases in recent years, notably for AIDS research due to their sensitivity to HIV-1. Northern pig-tailed macaques(M. leonina) are distributed in China and other surrounding Southeast Asia countries. Although northern pig-tailed macaques have been bred on a large scale as experimental animals since 2012, the reference value of normal levels of leukocytes is not available. To obtain such information, 62 blood samples from male and female healthy northern pig-tailed macaques at different ages were collected. The normal range of major leukocyte subpopulations, such as T lymphocytes, B lymphocytes, natural killer(NK) cells, monocytes, and the expression levels of activation or differentiation related molecules(CD38, HLA-DR, CCR5, CD21, IgD, CD80 and CD86) on lymphocytes were analyzed by flow cytometry. The counts of B cells decreased with age, but those of CD8+ T cells and NK cells and the frequency of CD38+HLA-DR+CD4+ T cells were positively correlated with age. The counts of leukocyte subpopulations were higher in males than those in females except for CD4+ T cells. Males also showed higher expression levels of Ig D and CD21 within B cells. This study provides basic data about the leukocyte subpopulations of northern pig-tailed macaques and compares this species with commonly used Chinese rhesus macaques(M. mulatta), which is meaningful for the biomedical application of northern pig-tailed macaques.

Binder jetting 3D printing process optimization for rapid casting of green parts with high tensile strength

Binder jetting 3D printing is a rapid,cost effective,and efficient moulding/core making process,which can be applied to a large variety of materials.However,it exhibits a relatively low green-part strength.This may cause the collapse of the printed parts during de-caking and the pick-up procedure,especially in the case of small-scale structures,such as thin walls,tips,and channels.In this work,polyvinyl alcohol(PVA)was used as the additive in coated sand powder.By exploiting the binding effect between the two composites(thermoplastic phenolic resin and PVA)triggered by the binder,bonding necks firmly form among the sand particles,improving the green-part strength of the coated sand printed parts.Experiments based on the Taguchi method were used to investigate the relationship between the process parameters and the green-part tensile strength.The following set of optimal process parameters was identified:50wt.%alcoholicity of the binder,75%binder saturation,0.36 mm layer thickness and 4.5wt.%PVA content.Further,the effect of such parameters on the green-part tensile strength was determined via statistical analysis.The green part of an engine cylinder head sand pattern with complex cavity structures was printed,and the green-part tensile strength reached 2.31 MPa.Moreover,the ZL301 aluminum alloy impeller shape casting was prepared using sand molds printed with the optimal process parameters.The results confirm that the proposed binder jetting 3D printing process can guarantee the integrity of the printed green parts and of small-size structures during de-caking and the pick-up procedure.Furthermore,the casting made from the printed sand molds exhibits a relatively high quality.

HIV-1 can infect northern pig-tailed macaques(Macaca leonina) and form viral reservoirs in vivo

Viral reservoirs of HIV-1 are a major obstacle for curing AIDS. The novel animal models that can be directly infected with HIV-I will contribute to develop effective strategies for eradicating infections. Here, we inoculated 4 northern pig-tailed macaques （NPM） with the HIV-1 strain HIV-1NL4.3 and moni- tored the infection for approximately 3 years （150 weeks）. The HIV-l-infected NPMs showed transient viremia for about 10 weeks after infection. However, cell-associated proviral DNA and viral RNA persisted in the peripheral blood and lymphoid organs for about 3 years. Moreover, replication-competent HIV-1 could be successfully recovered from peripheral blood mononuclear cells （PBMCs） during long-term infection. The numbers of resting CD4~ T cells in HIV-1 infected NPMs harboring proviruses fell within a range of 2- to 3-1oglo per million cells, and these proviruses could be reactivated both ex vivo and in vivo in response to co-stimulation with the latency-reversing agents JQ1 and prostratin. Our results suggested that NPMs can be infected with HIV-1 and a long-term viral reservoir was formed in NPMs, which might serve as a potential model for HIV-1 reservoir research.