Abstract: Abstract］ ObjectiveThe immune function of the mice was detected through the in vivo experiment in mice, which will provide theoretical basis for the development of the bacterial combined vaccine of respiratory tract infection in our country. Methods①Six common bacterias in children with respiratory tract infection in our country were isolated and cultured.  Bacterial proteins were prepared by washing, ultrasonic crushing, precipitation, dialysis and spectrophotometer, and the equivalent amount of the mixture was used as the experimental combined vaccine. ②Forty specific pathogen free mice were randomly divided into four groups, with 10 rats in each group. All mice were fed with a basal diet.After adaptive feeding for 10 days, the experimental group were fed with concentrations of 01, 02, 04 g/L combined vaccine, with daily morning irrigation of 02 mL. The mice in normal control group were orally administered daily with  physiological saline 02 mL. All groups were immuned for 10 days. Effects of combined vaccine on the phagocytic function of macrophage,the cellular immune function of mice, the changes of serum hemolysin content and the effect of thymus index and spleen index determinated. ResultsCompared with the normal control group, the macrophage phagocytic rate and phagocytic index,left and right foot weight, the absorbance value of serum hemolysin, the spleen index and thymus index of combined vaccine groups were significantly increased(P＜005). In the experimental design of vaccine concentration range, the detection values in different groups were increased with the increasement of vaccine concentration, and there were significant differences among the test groups(P＜005). ConclusionCombined vaccine can improve the immune function of organism. Combined vaccine can not only improve the cellular immune function, but also has obvious effect on humoral immune function. In the experimental concentration range, the higher the vaccine concentration, the more obvious effect on the immune function of the body.

Key words: respiratory tract infections, vaccines, immunity