HIV‐1 p24–immunoglobulin fusion molecule: a new strategy for plant‐based protein production

Abstract

SummaryWe describe the engineering of a human immunodeficiency virus-1 (HIV-1) p24-immunoglobulin A (IgA) antigen-antibody fusion molecule for therapeutic purposes and its enhancing effect on fused antigen expression in tobacco plants. Although many recombinant proteins have been expressed in transgenic plants as vaccine candidates, low levels of expression are a recurring problem. In this paper, using the HIV p24 core antigen as a model vaccine target, we describe a strategy for increasing the yield of a recombinant protein in plants. HIV p24 antigen was expressed as a genetic fusion with the α 2 and α 3 constant region sequences from human Ig α -chain and targeted to the endomembrane system. The expression of this fusion protein was detected at levels approximately 13-fold higher than HIV p24 expressed alone, and a difference in the behaviour of the two recombinant proteins during trafficking in the plant secretory pathway has been identified.

The extradomain A of fibronectin (EDA) combined with poly(I:C) enhances the immune response to HIV-1 p24 protein and the protection against recombinant Listeria monocytogenes-Gag infection in the mouse model

“…EDAp24 was purified from the soluble bacterial fraction whereas the p24 protein (produced in the absence of EDA) accumulated in inclusion bodies, when expressed in either the auto-inducible or the IPTG induction system. This is in contrast with previous studies where p24 was extracted mainly from the soluble fraction [27], likely due to the different bacterial expression system employed in that study. In any case, conserved protein conformation and maintenance of p24 antigen properties were confirmed in both p24 and EDAp24 recombinant proteins, as both molecules had the expected molecular weight in WB and p24 epitopes were recognized with monoclonal antibodies in ELISA sandwich assays.…”

Dual targeting of a mature plastoglobulin/fibrillin fusion protein to chloroplast plastoglobules and thylakoids in transplastomic tobacco plants

“…The PGL35 fusion partners were initially selected for their potential interest as vaccines. HIVp24 is expected to be a key component of an AIDS vaccine (Obregon et al 2006) and HCV core protein is a target of vaccine development for Hepatitis C disease (Elmowalid et al 2007). The HIVp24 sequence used here had the additional advantage of being optimized for plastid expression (Zhou et al 2008).…”

Manufacturing antibodies in the plant cell

“…Taking advantage of the stability conferred by IgG constant regions during expression in plants, chimeric molecules containing an antigenic (HIV-1 p24) region fused to Cγ1-2 regions of IgG H chain have been shown to stabilize antigen production [29]. In another example, antibody fusion with elastin like proteins was shown to increase anti-HIV mAb yields and to facilitate downstream processing, without affecting neither their properties nor their glycosylation patterns [30,31].…”