[Anti-tumor Immunity of Newcastle Disease Virus HN Protein is Influenced by Differential Subcellular Targeting]

Background And Objective: Hemagglutinin-neuraminidase (HN) protein of newcastle disease virus is an important immunogen for oncolysis. We designed three different expression plasmids encoding the HN protein targeted to different subcellular compartments: cytoplasmic (Cy-HN), secreted (Sc-HN) and membrane-anchored (M-HN). On the basis of antitumor effect in vitro, the aim of this study is to investigate the anti-tumor immunity effect of HN protein in vivo.

Methods: In the present study, we developed a mouse model in order to evaluate the anti-tumor effect of the intratumorally injected modified HN proteins and the anti-tumor immunity by lymphocyte proliferative response and CTL activity test.

Results: Although all three DNA constructs elicited an immune response, tumor-bearing mice intratumorally injected with M-HN demonstrated a significantly better anti-tumor effect than those injected with Cy-HN or Sc-HN (Day 18: P=0.022; Day 21: P<0.01). It also showed that this anti-tumor effect was mediated by higher lymphocyte proliferative response and CTL activity in mice intratumorally injected with M-HN [M-HN vs Cy-HN, P=0.019; M-HN vs Sc-HN, P=0.043; M-HN vs pcDNA3.1(+), P<0.01].

Conclusion: The anti-tumor immunity of Newcastle disease virus HN protein is influenced by differential subcellular targeting. The membrane-anchored form of the HN protein appears to be an ideal candidate to improve the specific cellular immunity.