Effect of active immunization against a recombinant mouse granulocyte-macrophage colony-stimulating factor/somatostatin fusion protein on the growth of mice.

Female BALB/c mice were actively immunized subcutaneously with a recombinant protein of granulocyte-macrophage colony-stimulating factor (GM-CSF) fused with somatostatin (SS) (GM-CSF/SS). Fifty-four days after the primary immunization, the body weight of the immunized mice increased by 4.62% compared with the control (P < 0.05), together with the induction of detectable serum antibodies against SS. The level of serum growth hormone (GH) elevated by 44.54% (P < 0.05) and the mRNA expression of muscular IGF-1 increased by 94% for the GM-CSF/SS-treated mice. The results indicated that the recombinant protein GM-CSF/SS was efficient in inducing specific immunity against SS, subsequently leading to the increase of the GH level by SS neutralization, and ultimately improving the growth of mice.