Non-human primates are widely used animal models in studying pathological mechanisms of HIV/SIV infections due to their close evolutionary status with human being. The pig-tailed macaque, which can be divided into three species based on morphological characteristics and geographic distribution, i.e., Southern pig-tailed macaque (Macaca nemestrina), Northern pig-tailed macaque (NPMs, M.leonina) and Mentawai macaque (M. pagensis), is an Old-World monkey known to be susceptible to HIV-1 infection.
Recently, Prof. ZHENG Yongtang's team at Kunming Institute of Zoology of Chinese Academy of Sciences, for the first time reported that in SIVmac239-infected NPMs, they retained superior intestinal integrity and limited microbial translocation, which were associated with lower immune activation compared with that in Chinese rhesus macaques (ChRMs, M. mulatta).
Microbial translocation isthe non-physiological passage of the gastrointestinal microflora through the intestinal epithelial barrier and the lamina propria and eventually to local mesenteric lymph nodes and, from there, to extranodal sites. In pathogenic SIV and HIV infections, the microbial translocation has been proposed as a major driver of systemic immune activation, whereas, immune activation is a hallmark of HIV/SIV infection and is difficult to alleviate. Therefore, therapeutic strategies target on microbial products and their downstream effects to relieve persistent immune activation are needed for patients to improve life quality.
In this study, the levels of CD8+ T cell activation and plasma biomarkers of microbial translocation in SIVmac239-infected NPMs and ChRMs and normal NPMs were analyzed. Moreover, the status of microbial translocation, intestinal integrity and microbial translocation of NPMs were studied. This research on intestinal mucosal immunity in NPMs not only shed lights on guidance for therapeutic strategies of microbial translocation in HIV-1-infected patients, but also provides deeper insight into the mechanisms of microbial translocation during HIV-1 infection. The main findings of this study have published online in Zoological Research.