Expression and Identification of Immunological Activities of the HIV‐gp120N‐Human Interferon Gamma Fusion Protein

The human immunodeficiency virus type 1 (HIV‐1) envelope glycoprotein gp120 is a vaccine immunogen that has been studied extensively. To enhance the immune response of cells against HIV‐1 gp120, we tested the coexpression of gp120N with interferon‐γ (IFN‐γ) as an immune adjuvant. Two recombinant prokaryotic plasmids were constructed: the pET44b‐HIV‐1‐gp120N plasmid construct carried the HIV‐1 gp120N gene (pET44‐gp120N), whereas the pET44b‐HIV‐1‐gp120N‐IFN‐γ plasmid construct carried a fusion gp120N‐IFN‐γ gene (pET44b‐gp120N‐IFN‐γ). Target protein expression was achieved in E. coli BL21 (DE3) cells by chemical induction. To test the immunological activity of the proteins, mice were injected with a control, gp120N, or the fusion gp120N‐IFN‐γ protein. The serum and spleen cells of the mice were collected for immunological detection. Results showed that specific T lymphocyte proliferation and the expression of the Th1‐type cytokines (IL‐2 and IFN‐γ) were higher in the gp120N‐IFN‐γ group than the other two groups (P < 0.05). No difference was observed in the expression levels of the Th2‐type cytokines (IL‐4 and IL‐10; P > 0.05). These results suggest that IFN‐γ plays a prominent role as an immune adjuvant when coexpressed with HIV‐1 gp120N. IFN‐γ enhances the specific cell immune response of mice against HIV‐1 gp120. Anat Rec, 292:381–386, 2009. © 2009 Wiley‐Liss, Inc.