The northern pig-tailed macaque (NPM, Macaca leonina
) has become a widely used animal model in biomedical research. In this study, we measured serum immunoglobulin IgG, IgM, IgA, complement C3, C4 and CRP levels in 3-11 year old captive northern pig-tailed macaques using HITACHI 7600-20 automated chemistry analyzer in order to determine the influences of age and gender on these items. The results showed that serum IgA, IgM, C3 and C4 levels were not correlated with age (P
>0.05), while serum IgG levels increased progressively with age (r
=0.045). Serum IgG, IgA, IgM and C3 levels were higher in females than in males (P
<0.05). Moreover, serum C3 concentration was both positively and strongly correlated with that of C4 (r
<0.0001). This study provides basic serum immunoglobulin and complement data of captive northern pig-tailed macaques, which may prove useful for future breeding efforts and biomedical research.