The Immunologic Background Of Chinese-origin Rhesus Macaques

Rhesus macaques(Macaca mulatta) have long been used to establish animal models for various human diseases including AIDS.In the past Indian rhesus macaques were almost exclusively used in the biomedical researches.More and more Chinese rhesus macaques are used in the corresponding researches due to the drying up of Indian rhesus macaque resources.Differences in morphology,physiology, behavior,and immune responses have been observed between the Indian and Chinese rhesus macaques.However,little is known about the immunologic background of the Chinese rhesus macaques,which hinders the use of these animals.The percentage and the count of CD4+T lymphocyte are important parameters for health status,immune responses,and disease progression.CD4+T lymphocyte was divided into several subsets of different effector or regulatory functions.Major Histocompatibility Complex(MHC) plays critical roles in antigen presentation in the adaptive immunity and the polymorphism of which is closely related to microbial infection susceptibility/resistance.In an effort to expand the knowledge about the immunologic background of these animals,we analyzed the normal range of CD4+T lymphocyte and the polymorphism of some MHC classⅠand classⅡgenes of Chinese rhesus macaques.Firstly,we analyzed the complete blood count and the percentage and count of CD4+T lymphocyte by using an automated haemacytometer and by flow cytometry. The percentage of CD+T lymphocyte(51.4±9.6%) and the CD4+/CD8+ratio (1.27±0.55) decreased with age while the percentage of CD3+T lymphocyte (55.3±13.3%),the percentage of CD8+T lymphocyte(42.0±9.7%) and the percentage of the CD4+CD8+T lymphocyte(1.3±0.9%) increased with age.The CD3+CD4+CD25+T lymphocyte were divided into two groups:CD3+CD4+CD25^high and CD3+CD4+CD25^med.CD3+CD4+CD25^high lymphocytes were about 0.3%-5.5% among the CD4+T lymphocyte and the average was 2.5%,CD3+CD4+CD25^med were about 6.6%.IL-17A+ cells were observed in all the 6 normal rhesus macaques but there were very few before cultured with PMA+Ionomycin.About 1.4%of lymphocytes were IL-17A+ cells after stimulation and short-term cultivation,and about 2.7%of CD3+CD4+ lymphocytes were IL-17A+ cells,i.e.Th17 cells.Th17 cells in the 4 SHIV infected rhesus monkeys were also examined.The number of the Th17 cells detected after stimulation and short-term cultivation was not significantly different from that of normal monkeys.Next,we detected major histocompatibility complex(MHC) classⅠcDNAs in 169 Chinese rhesus macaques and detected 172 distinct Mamu-A sequences.132of these classⅠcDNAs were novel,while 40 of these sequences were previously reported in Chinese and Indian rhesus macaques.And from the results,we deduced the positive rate of the Mamu-A alleles in Chinese rhesus macaques,the most popular allele was Mamu-A1*4902(12.43%),the next was Mamu-A1*0304(10.65%),all the other alleles positive rate were below 10%.The peptide binding domain has more amino acid substitution compared with the Indian rhesus macaques.In this study,we collected 105 monkey samples and detected 37 Mamu-DQB1 alleles.27 were the former reported in Chinese or Indian rhesus macaques and the other 10 were novel sequences.In the 178 samples tested in this study,15 samples were found positive by PCR for Mamu-DRB*W101 and 12 samples positive for Mamu-DRB*W201.The positive rate of Mamu-DRB*W101 and Mamu-DRB*W201 among the Chinese macaques tested in the study was 8.43%and 6.74%respectively.The count and percentage of CD4+T lymphocyte subset and the MHC sequences discovered in this study enriched our knowledge of the Chinese rhesus macaques and will be useful in the future studies.