The first evidence that plants represent a valid, safe and cost-effective alternative to traditional expression systems for large-scale production of antigens and antibodies was described more than 10 years ago. Since then, considerable improvements have been made to increase the yield of plant-produced proteins. These include the use of signal sequences to target proteins to different cellular compartments, plastid transformation to achieve high transgene dosage, codon usage optimization to boost gene expression, and protein fusions to improve recombinant protein stability and accumulation. Thus, several HIV/SIV antigens and neutralizing anti-HIV antibodies have recently been successfully expressed in plants by stable nuclear or plastid transformation, and by transient expression systems based on plant virus vectors or Agrobacterium-mediated infection. The current article gives an overview of plant expressed HIV antigens and antibodies and provides an account of the use of different strategies aimed at increasing the expression of the accessory multifunctional HIV-1 Nef protein in transgenic plants. © Springer Science+Business Media B.V. 2009.

Cited By :14Export Date: 16 July 2015CODEN: TRSEECorrespondence Address: Marusic, C.; Dipartimento BAS, Sezione Genetica e Genomica Vegetale, ENEA, C.R. Casaccia, via Anguillarese 301, 00123 Rome, Italy; email: carla.marusic@casaccia.enea.itChemicals/CAS: HIV Antibodies; HIV Antigens; nef Gene Products, Human Immunodeficiency Virus; nef protein, Human immunodeficiency virus 1References: Azad, A.A., Failla, P., Lucantoni, A., Bentley, J., Mardon, C., Wolfe, A., Fuller, K., Macreadie, I., Large-scale production and characterization of recombinant human immunodeficiency virus type 1 Nef (1994) J Gen Virol, 75, pp. 651-655. , doi:10.1099/0022-1317-75-3-651;Bakker, H., Rouwendal, G.J., Karnoup, A.S., Florack, D.E., Stoopen, G.M., Helsper, J.P., van Ree, R., Bosch, D., An antibody produced in tobacco expressing a hybrid beta-1,4-galactosyltransferase is essentially devoid of plant carbohydrate epitopes (2006) Proc Natl Acad Sci USA, 103, pp. 7577-7582. , doi:10.1073/pnas.0600879103; Barbante, A., Irons, S., Hawes, C., Frigerio, L., Vitale, A., Pedrazzini, E., Anchorage to the cytosolic face of the ER membrane: Anew strategy to stabilize a cytosolic recombinant antigen in plants (2008) Plant Biotechnol J, 6, pp. 560-575. , doi:10.1111/j.1467-7652.2008.00342.x; Beachy, R.N., Fitchen, J.H., Hein, M.B., Use of plant viruses for delivery of vaccine epitopes (1996) Ann N Y Acad Sci, 792, pp. 43-49. , doi:10.1111/j.1749-6632.1996.tb32489.x; Benchabane, M., Goulet, C., Rivard, D., Faye, L., Gomord, V., Michaud, D., Preventing unintended proteolysis in plant protein biofactories (2008) Plant Biotechnol J, 6, pp. 633-648. , doi:10.1111/j.1467-7652.2008.00344.x; Bock, R., Transgenic chloroplasts in basic research and plant biotechnology (2001) J Mol Biol, 312, pp. 425-438. , doi:10.1006/jmbi.2001.4960; Bock, R., Plastid biotechnology: Prospects for herbicide and insect resistance, metabolic engineering and molecular farming (2007) Curr Opin Biotechnol, 18, pp. 100-106. , doi:10.1016/j.copbio.2006.12.001; Borgese, N., D’Arrigo, A., De Silvestris, M., Pietrini, G., NADH-cytochrome b5 reductase and cytochrome b5 isoforms as models for the study of post-translational targeting to the endoplasmic reticulum (1993) FEBS Lett, 325, pp. 70-75. , doi:10.1016/0014-5793(93)81416-W; Borgese, N., Colombo, S., Pedrazzini, E., The tale of tail-anchored proteins: Coming from the cytosol and looking for a membrane (2003) J Cell Biol, 161, pp. 1013-1019. , doi:10.1083/jcb.200303069; Borgese, N., Francolini, M., Snapp, E., Endoplasmic reticulum architecture: Structures in flux (2006) Curr Opin Cell Biol, 18, pp. 358-364. , doi:10.1016/j.ceb.2006.06.008; Coleman, C.E., Herman, E.M., Takasaki, K., Larkins, B.A., The maize γ-zein sequesters α-zein and stabilizes its accumulation in protein bodies of transgenic tobacco endosperm (1996) Plant Cell, 8, pp. 2335-2345; Collins, K.L., Chen, B.K., Kalams, S.A., Walker, B.D., Baltimore, D., HIV-1 Nef protein protects infected primary cells against killing by cytotoxic T lymphocytes (1998) Nature, 391, pp. 397-401. , doi:10.1038/34929; Conley, A.J., Kessler, J.A., Boots, L.J., Tung, J.S., Arnold, B.A., Keller, P.M., Shaw, A.R., Emini, E.A., Neutralization of divergent human immunodeficiency virus type 1 variants and primary isolates by IAM-41-2F5, an anti-gp41 human monoclonal antibody (1994) Proc Natl Acad Sci USA, 91, pp. 3348-3352. , 2nd, doi:10.1073/pnas.91.8.3348; Cooke, S.J., Coates, K., Barton, C.H., Biggs, T.E., Barrett, S.J., Cochrane, A., Oliver, K., Mann, D.A., Regulated expression vectors demonstrate cell-type-specific sensitivity to human immunodeficiency virus type 1 Nef-induced cytostasis (1997) J Gen Virol, 78, pp. 381-392; Cox, K.M., Sterling, J.D., Regan, J.T., Gasdaska, J.R., Frantz, K.K., Peele, C.G., Black, A., Dickey, L.F., Glycan optimization of a human monoclonal antibody in the aquatic plant Lemna minor (2006) Nat Biotechnol, 24, pp. 1591-1597. , doi:10.1038/nbt1260; Daniell, H., Production of biopharmaceuticals and vaccines in plants via the chloroplast genome (2006) Biotechnol J, 1, pp. 1071-1079. , doi:10.1002/biot.200600145; de Virgilio, M., De Marchis, F., Bellucci, M., Mainieri, D., Rossi, M., Benvenuto, E., Arcioni, S., Vitale, A., The human immunodeficiency virus antigen Nef forms protein bodies in leaves of transgenic tobacco when fused to zeolin (2008) J Exp Bot, 59, pp. 2815-2829. , doi:10.1093/jxb/ern143; Denecke, J., Botterman, J., Deblaere, R., Protein secretion in plant cells can occur via a default pathway (1990) Plant Cell, 2, pp. 51-59; Doran, P.M., Foreign protein degradation and instability in plants and plant tissue cultures (2006) Trends Biotechnol, 24, pp. 426-432. , doi:10.1016/j.tibtech.2006.06.012; Durrani, Z., McInerney, T.L., McLain, L., Jones, T., Bellaby, T., Brennan, F.R., Dimmock, N.J., Intranasal immunization with a plant virus expressing a peptide from HIV-1 gp41 stimulates better mucosal and systemic HIV-1-specific IgA and IgG than oral immunization (1998) J Immunol Methods, 220, pp. 93-103. , doi:10.1016/S0022-1759(98)00145-8; Fauci, A.S., Johnston, M.I., Dieffenbach, C.W., Burton, D.R., Hammer, S.M., Hoxie, J.A., Martin, M., Greene, W.C., HIV vaccine research: The way forward (2008) Science, 321, pp. 530-532. , doi:10.1126/science.1161000; Floss, D.M., Sack, M., Stadlmann, J., Rademacher, T., Scheller, J., Stöger, E., Fischer, R., Conrad, U., Biochemical and functional characterization of anti-HIV antibody-ELP fusion proteins from transgenic plants (2008) Plant Biotechnol J, 6, pp. 379-391. , doi:10.1111/j.1467-7652.2008.00326.x; Frigerio, L., Pastres, A., Prada, A., Vitale, A., Influence of KDEL on the fate of trimeric or assembly-defective phaseolin: Selective use of an alternative route to vacuoles (2001) Plant Cell, 13, pp. 1109-1126; Fujiyama, K., Furukawa, A., Katsura, A., Misaki, R., Omasa, T., Seki, T., Production of mouse monoclonal antibody with galactose-extended sugar chain by suspension cultured tobacco BY2 cells expressing human beta (1, 4)-galactosyltransferase (2007) Biochem Biophys Res Commun, 358, pp. 85-91. , doi:10.1016/j.bbrc.2007.04.054; Geli, M.I., Torren, M., Ludevid, D., Two structural domains mediate two sequential events in γ-zein targeting: Protein endoplasmic reticulum retention and protein body formation (1994) Plant Cell, 6, pp. 1911-1922; Geyer, M., Peterlin, B.M., Domain assembly, surface accessibility and sequence conservation in full length HIV-1 Nef (2001) FEBS Lett, 496, pp. 91-95. , doi:10.1016/S0014-5793(01)02394-8; Geyer, M., Munte, C.E., Schorr, J., Kellner, R., Kalbitzer, H.R., Structure of the anchor-domain of myristoylated and non-myristoylated HIV-1 Nef protein (1999) J Mol Biol, 289, pp. 123-138. , doi:10.1006/jmbi.1999.2740; Geyer, M., Fackler, O.T., Peterlin, B.M., Structure-function relationships in HIV-1 Nef (2001) EMBO Rep, 2, pp. 580-585. , doi:10.1093/embo-reports/kve141; Goepfert, P.A., Tomaras, G.D., Horton, H., Montefiori, D., Ferrari, G., Deers, M., Voss, G., Evans, T., NIAID HIV vaccine trials network. Durable HIV-1 antibody and T-cell responses elicited by an adjuvanted multi-protein recombinant vaccine in uninfected human volunteers (2007) Vaccine, 25, pp. 510-518. , doi:10.1016/j.vaccine.2006.07.050; Hiatt, A., Cafferkey, R., Bowdish, K., Production of antibodies in transgenic plants (1989) Nature, 342, pp. 76-78. , doi:10.1038/342076a0; Horn, M.E., Pappu, K.M., Bailey, M.R., Clough, R.C., Barker, M., Jilka, J.M., Howard, J.A., Streatfield, S.J., Advantageous features of plant-based systems for the development of HIV vaccines (2003) J Drug Target, 11, pp. 539-545. , doi:10.1080/10611860410001669992; Jin, C., Altmann, F., Strasser, R., Mach, L., Schähs, M., Kunert, R., Rademacher, T., Steinkellner, H., A plant-derived human monoclonal antibody induces an anti-carbohydrate immune response in rabbits (2008) Glycobiology, 18, pp. 235-241. , doi:10.1093/glycob/cwm137; Joelson, T., Akerblom, L., Oxelfelt, P., Strandberg, B., Tomenius, K., Morris, T.J., Presentation of a foreign peptide on the surface of tomato bushy stunt virus (1997) J Gen Virol, 78, pp. 1213-1217; Karasev, A.V., Foulke, S., Wellens, C., Rich, A., Shon, K.J., Zwierzynski, I., Hone, D., Reitz, M., Plant based HIV-1 vaccine candidate: Tat protein produced in spinach (2005) Vaccine, 23, pp. 1875-1880. , doi:10.1016/j.vaccine.2004.11.021; Kim, T.G., Ruprecht, R., Langridge, W.H., Synthesis and assembly of a cholera toxin B subunit SHIV 89.6p Tat fusion protein in transgenic potato (2004) Protein Expr Purif, 35, pp. 313-319. , doi:10.1016/j.pep.2004.02.007; Kim, T.G., Ruprecht, R., Langridge, W.H., SIVmac Gag p27 capsid protein gene expression in potato (2004) Protein Expr Purif, 36, pp. 312-317. , doi:10.1016/j.pep.2004.04.015; Kim, T.G., Gruber, A., Ruprecht, R.M., Langridge, W.H., Synthesis and assembly of SIVmac Gag p27 capsid protein cholera toxin B subunit fusion protein in transgenic potato (2004) Mol Biotechnol, 28, pp. 33-40. , doi:10.1385/MB:28:1:33; Kim, T.G., Gruber, A., Langridge, W.H., HIV-1 gp120 V3 cholera toxin B subunit fusion gene expression in transgenic potato (2004) Protein Expr Purif, 37, pp. 196-202. , doi:10.1016/j.pep.2004.04.014; Kohleisen, B., Gaedigk-Nitschko, K., Ohlmann, M., Götz, E., Ostolaza, H., Goni, F.M., Erfle, V., Heparin-binding capacity of the HIV-1 NEF-protein allows one-step purification and biochemical characterization (1996) J Virol Methods, 60, pp. 89-101. , doi:10.1016/0166-0934(96)02049-6; Koop, H.U., Herz, S., Golds, T.J., Nickelsen, J., The genetic transformation of plastids (2007) Top Curr Genet, 19, pp. 457-510. , doi:10.1007/4735_2007_0225; Ma, J.K., Hiatt, A., Hein, M., Vine, N.D., Wang, F., Stabila, P., van Dolleweerd, C., Lehner, T., Generation and assembly of secretory antibodies in plants (1995) Science, 268, pp. 716-719. , doi:10.1126/science.7732380; Ma, J.K., Drake, P.M., Christou, P., The production of recombinant pharmaceutical proteins in plants (2003) Nat Rev Genet, 4, pp. 794-805. , doi:10.1038/nrg1177; Ma, J.K., Barros, E., Bock, R., Christou, P., Dale, P.J., Dix, P.J., Fischer, R., Twyman, R.M., Molecular farming for new drugs and vaccines. Current perspectives on the production of pharmaceuticals in transgenic plants (2005) EMBO Rep, 6, pp. 593-599. , doi:10.1038/sj.embor.7400470; Macreadie, I.G., Fernley, R., Castelli, L.A., Lucantoni, A., White, J., Azad, A., Expression of HIV-1 nef in yeast causes membrane perturbation and release of the myristylated Nef protein (1998) J Biomed Sci, 5, pp. 203-210; Maggiorella, M.T., Sernicola, L., Crostarosa, F., Belli, R., Pavone-Cossut, M.R., Macchia, I., Farcomeni, S., Titti, F., Multiprotein genetic vaccine in the SIV-Macaca animal model: A promising approach to generate sterilizing immunity to HIV infection (2007) J Med Primatol, 36, pp. 180-194. , doi:10.1111/j.1600-0684.2007.00236.x; Mainieri, D., Rossi, M., Archinti, M., Bellucci, M., De Marchis, F., Vavassori, S., Pompa, A., Vitale, A., Zeolin A new recombinant storage protein constructed using maize γ-zein and bean phaseolin (2004) Plant Physiol, 136, pp. 3447-3456. , doi:10.1104/pp.104.046409; Maliga, P., Plastid transformation in higher plants (2004) Annu Rev Plant Biol, 55, pp. 289-313. , doi:10.1146/annurev.arplant.55.031903.141633; Marusic, C., Rizza, P., Lattanzi, L., Mancini, C., Spada, M., Belardelli, F., Benvenuto, E., Capone, I., Chimeric plant virus particles as immunogens for inducing murine and human immune responses against human immunodeficiency virus type 1 (2001) J Virol, 75, pp. 8434-8439. , doi:10.1128/JVI.75.18.8434-8439.2001; Marusic, C., Nuttall, J., Buriani, G., Lico, C., Lombardi, R., Baschieri, S., Benvenuto, E., Frigerio, L., Expression, intracellular targeting and purification of HIV Nef variants in tobacco cells (2007) BMC Biotechnol, 7, p. 12. , doi:10.1186/1472-6750-7-12; Matoba, N., Magérus, A., Geyer, B.C., Zhang, Y., Muralidharan, M., Alfsen, A., Arntzen, C.J., Mor, T.S., A mucosally targeted subunit vaccine candidate eliciting HIV-1 transcytosis-blocking Abs (2004) Proc Natl Acad Sci USA, 101, pp. 13584-13589. , doi:10.1073/pnas.0405297101; McCabe, M.S., Klaas, M., Gonzalez-Rabade, N., Poage, M., Badillo-Corona, J., Zhou, F., Karcher, D., Dix, P.J., Plastid transformation of high biomass tobacco variety Maryland Mammoth for production of HIV-1 p24 antigen (2008) Plant Biotech J, 6, pp. 914-929. , doi:10.1111/j.1467-7652.2008.00365.x; McInerney, T.L., Brennan, F.R., Jones, T.D., Dimmock, N.J., Analysis of the ability of five adjuvants to enhance immune responses to a chimeric plant virus displaying an HIV-1 peptide (1999) Vaccine, 17, pp. 1359-1368. , doi:10.1016/S0264-410X(98)00388-0; McLain, L., Porta, C., Lomonossoff, G.P., Durrani, Z., Dimmock, N.J., Human immunodeficiency virus type 1-neutralizing antibodies raised to a glycoprotein 41 peptide expressed on the surface of a plant virus (1995) AIDS Res Hum Retroviruses, 11, pp. 327-334; McLain, L., Durrani, Z., Wisniewski, L.A., Porta, C., Lomonossoff, G.P., Dimmock, N.J., Stimulation of neutralizing antibodies to human immunodeficiency virus type 1 in three strains of mice immunized with a 22 amino acid peptide of gp41 expressed on the surface of a plant virus (1996) Vaccine, 14, pp. 799-810. , doi:10.1016/0264-410X(95)00229-T; Meyers, A., Chakauya, E., Shephard, E., Tanzer, F.L., Maclean, J., Lynch, A., Williamson, A.L., Rybicki, E.P., Expression of HIV-1 antigens in plants as potential subunit vaccines (2008) BMC Biotechnol, 8, p. 53. , doi:10.1186/1472-6750-8-53; Obregon, P., Chargelegue, D., Drake, P.M., Prada, A., Nuttall, J., Frigerio, L., Ma, J.K., HIV-1 p24-immunoglobulin fusion molecule: A new strategy for plant-based protein production (2006) Plant Biotechnol J, 4, pp. 195-207. , doi:10.1111/j.1467-7652.2005.00171.x; Oey, M., Lohse, M., Kreikemeyer, B., Bock, R., Exhaustion of the chloroplast protein synthesis capacity by massive expression of a highly stable protein antibiotic (2008) Plant J, , doi:10.1111/j.1365-313X.2008.03702.x; Patel, J., Zhu, H., Menassa, R., Gyenis, L., Richman, A., Brandle, J., Elastin-like polypeptide fusions enhance the accumulation of recombinant proteins in tobacco leaves (2007) Transgenic Res, 16, pp. 239-249. , doi:10.1007/s11248-006-9026-2; Peng, B., Robert-Guroff, M., Deletion of N-terminal myristoylation site of HIV Nef abrogates both MHC-1 and CD4 down-regulation (2001) Immunol Lett, 78, pp. 195-200. , doi:10.1016/S0165-2478(01)00250-4; Peng, B., Voltan, R., Cristillo, A.D., Alvord, W.G., Davis-Warren, A., Zhou, Q., Murthy, K.K., Robert-Guroff, M., Replicating Ad-recombinants encoding non-myristoylated rather than wild-type HIV Nef elicit enhanced cellular immunity (2006) AIDS, 20, pp. 2149-2157. , doi:10.1097/QAD.0b013e32801086ee; Porta, C., Spall, V.E., Loveland, J., Johnson, J.E., Barker, P.J., Lomonossoff, G.P., Development of cowpea mosaic virus as a high-yielding system for the presentation of foreign peptides (1994) Virology, 202, pp. 949-955. , doi:10.1006/viro.1994.1417; Rademacher, T., Sack, M., Arcalis, E., Stadlmann, J., Balzer, S., Altmann, F., Quendler, H., Stoger, E., Recombinant antibody 2G12 produced in maize endosperm efficiently neutralizes HIV-1 and contains predominantly single-GlcNAc N-glycans (2008) Plant Biotechnol J, 6, pp. 189-201. , doi:10.1111/j.1467-7652.2007.00306.x; Ramessar, K., Rademacher, T., Sack, M., Stadlmann, J., Platis, D., Stiegler, G., Labrou, N., Christou, P., Cost-effective production of a vaginal protein microbicide to prevent HIV transmission (2008) Proc Natl Acad Sci USA, 105, pp. 3727-3732. , doi:10.1073/pnas.0708841104; Ramírez, Y.J., Tasciotti, E., Gutierrez-Ortega, A., Donayre Torres, A.J., Olivera Flores, M.T., Giacca, M., Gómez Lim, M.A., Fruit-specific expression of the human immunodeficiency virus type 1 tat gene in tomato plants and its immunogenic potential in mice (2007) Clin Vaccine Immunol, 6, pp. 685-692. , doi:10.1128/CVI.00028-07; Roeth, J.F., Collina, K.L., Human immunodeficiency virus type 1 Nef: Adapting to intracellular trafficking pathways (2006) Microbiol Mol Biol Rev, 70, pp. 548-563. , doi:10.1128/MMBR.00042-05; Ruf, S., Karcher, D., Bock, R., Determining the transgene containment level provided by chloroplast transformation (2007) Proc Natl Acad Sci USA, 104, pp. 6998-7002. , doi:10.1073/pnas.0700008104; Sack, M., Paetz, A., Kunert, R., Bomble, M., Hesse, F., Stiegler, G., Fischer, R., Rademacher, T., Functional analysis of the broadly neutralizing human anti-HIV-1 antibody 2F5 produced in transgenic BY-2 suspension cultures (2007) FASEB J, 21, pp. 1655-1664. , doi:10.1096/fj.06-5863com; Schähs, M., Strasser, R., Stadlmann, J., Kunert, R., Rademacher, T., Steinkellner, H., Production of a monoclonal antibody in plants with a humanized N-glycosylation pattern (2007) Plant Biotechnol J, 5, pp. 657-663. , doi:10.1111/j.1467-7652.2007.00273.x; Schillberg, S., Twyman, R.M., Fischer, R., Opportunities for recombinant antigen and antibody expression in transgenic plants-technology assessment (2005) Vaccine, 23, pp. 1764-1769. , doi:10.1016/j.vaccine.2004.11.002; Shewry, P.R., Napier, J.A., Tatham, A.S., Seed storage proteins: Structures and biosynthesis (1995) Plant Cell, 7, pp. 945-956; Sinclair, E., Barbosa, P., Feinberg, M.B., The nef gene products of both simian and human immunodeficiency viruses enhance virus infectivity and are functionally interchangeable (1997) J Virol, 71, pp. 3641-3651; Sirén, N., Weegar, J., Dahlbacka, J., Kalkkinen, N., Fagervik, K., Leisola, M., vonWeymarn, N., Production of recombinant HIV-1 Nef (negative factor) protein using Pichia pastoris and a low-temperature fed-batch strategy (2006) Biotechnol Appl Biochem, 44, pp. 151-158. , doi:10.1042/BA20060001; Strasser, R., Stadlmann, J., Schähs, M., Stiegler, G., Quendler, H., Mach, L., Glössl, J., Steinkellner, H., Generation of glyco-engineered Nicotiana benthamiana for the production of monoclonal antibodies with a homogeneous human-like N-glycan structure (2008) Plant Biotechnol J, 6, pp. 392-402. , doi:10.1111/j.1467-7652.2008.00330.x; Streatfield, S.J., Approaches to achieve high-level heterologous protein production in plants (2007) Plant Biotechnol J, 5, pp. 2-15. , doi:10.1111/j.1467-7652.2006.00216.x; Sugiyama, Y., Hamamoto, H., Takemoto, S., Watanabe, Y., Okada, Y., Systemic production of foreign peptides on the particle surface of tobacco mosaic virus (1995) FEBS Lett, 359, pp. 247-250. , doi:10.1016/0014-5793(95)00054-D; Svab, Z., Maliga, P., Exceptional transmission of plastids and mitochondria from the transplastomic pollen parent and its impact on transgene containment (2007) Proc Natl Acad Sci USA, 104, pp. 7003-7008. , doi:10.1073/pnas.0700063104; Titti, F., Cafaro, A., Ferrantelli, F., Tripiciano, A., Moretti, S., Caputo, A., Gavioli, R., Ensoli, B., Problems and emerging approaches in HIV/AIDS vaccine development (2007) Expert Opin Emerg Drugs, 12, pp. 23-48. , doi:10.1517/14728214.12.1.23; Tobiume, M., Takahoko, M., Yamada, T., Tatsumi, M., Iwamoto, A., Matsuda, M., Inefficient enhancement of viral infectivity and CD4 downregulation by human immunodeficiency virus type 1 Nef from Japanese long-term nonprogressors (2002) J Virol, 76, pp. 5959-5965. , doi:10.1128/JVI.76.12.5959-5965.2002; Triguero, A., Cabrera, G., Cremata, J.A., Yuen, C.T., Wheeler, J., Ramírez, N.I., Plant-derived mouse IgG monoclonal antibody fused to KDEL endoplasmic reticulum-retention signal is N-glycosylated homogeneously throughout the plant with mostly high-mannose-type N-glycans (2005) Plant Biotechnol J, 3, pp. 449-457. , doi:10.1111/j.1467-7652.2005.00137.x; Trkola, A., Purtscher, M., Muster, T., Ballaun, C., Buchacher, A., Sullivan, N., Srinivasan, K., Katinger, H., Human monoclonal antibody 2G12 defines a distinctive neutralization epitope on the gp120 glycoprotein of human immunodeficiency virus type 1 (1996) J Virol, 70, pp. 1100-1108; Trkola, A., Kuster, H., Rusert, P., Joos, B., Fischer, M., Leemann, C., Manrique, A., Günthard, H.F., Delay of HIV-1 rebound after cessation of antiretroviral therapy through passive transfer of human neutralizing antibodies (2005) Nat Med, 11, pp. 615-622. , doi:10.1038/nm1244; Trkola, A., Kuster, H., Rusert, P., von Wyl, V., Leemann, C., Weber, R., Stiegler, G., Günthard, H.F., In vivo efficacy of human immunodeficiency virus neutralizing antibodies: Estimates for protective titers (2008) J Virol, 82, pp. 1591-1599. , doi:10.1128/JVI.01792-07; Vitale, A., Boston, R.S., Endoplasmic reticulum quality control and the unfolded protein response: Insights from plants (2008) Traffic, 9, pp. 1581-1588. , doi:10.1111/j.1600-0854.2008.00780.x; Vitale, A., Denecke, J., The endoplasmic reticulum-gateway of the secretory pathway (1999) Plant Cell, 11, pp. 615-628; Voss, G., Manson, K., Montefiori, D., Watkins, D.I., Heeney, J., Wyand, M., Cohen, J., Bruck, C., Prevention of disease induced by a partially heterologous AIDS virus in rhesus monkeys by using an adjuvanted multicomponent protein vaccine (2003) J Virol, 77, pp. 1049-1058. , doi:10.1128/JVI.77.2.1049-1058.2003; Walker, B.D., Burton, D.R., Toward an AIDS vaccine (2008) Science, 320, pp. 760-764. , doi:10.1126/science.1152622; Wandelt, C.I., Khan, M.R., Craig, S., Schroeder, H.E., Spencer, D., Higgins, T.J., Vicilin with carboxy-terminal KDEL is retained in the endoplasmic reticulum and accumulates to high levels in the leaves of transgenic plants (1992) Plant J, 2, pp. 181-192; Webster, D.E., Thomas, M.C., Pickering, R., Whyte, A., Dry, I.B., Gorry, P.R., Wesselingh, S.L., Is there a role for plant-made vaccines in the prevention of HIV/AIDS? (2005) Immunol Cell Biol, 83, pp. 239-247. , doi:10.1111/j.1440-1711.2005.01341.x; Yang, L., Suzuki, K., Hirose, S., Wakasa, Y., Takaiwa, F., Development of transgenic rice seed accumulating a major Japanese cedar pollen allergen (Cry j 1) structurally disrupted for oral immunotherapy (2007) Plant Biotechnol J, 5, pp. 815-826. , doi:10.1111/j.1467-7652.2007.00287.x; Yu, G., Felsted, R.L., Effect of myristoylation on p27 nef subcellular distribution and suppression of HIV-LTR transcription (1992) Virology, 187, pp. 46-55. , doi:10.1016/0042-6822(92)90293-X; Yusibov, V., Modelska, A., Steplewski, K., Agadjanyan, M., Weiner, D., Hooper, D.C., Koprowski, H., Antigens produced in plants by infection with chimeric plant viruses immunize against rabies virus and HIV-1 (1997) Proc Natl Acad Sci USA, 94, pp. 5784-5788. , doi:10.1073/pnas.94.11.5784; Zhang, G., Leung, C., Murdin, L., Rovinski, B., White, K.A., In planta expression of HIV-1 p24 protein using an RNA plant virus-based expression vector (2000) Mol Biotechnol, 14, pp. 99-107. , doi:10.1385/MB:14:2:99; Zhang, G., Rodrigues, L., Rovinski, B., White, K.A., Production of HIV-1 p24 protein in transgenic tobacco plants (2002) Mol Biotechnol, 20, pp. 131-136. , doi:10.1385/MB:20:2:131; Zhou, F., Badillo-Corona, J.A., Karcher, D., Gonzalez-Rabade, N., Piepenburg, K., Borchers, A.-M.I., Maloney, A.P., Bock, R., High-level expression of HIV antigens from the tobacco and tomato plastid genomes (2008) Plant Biotechnol J, 6, pp. 897-913. , doi:10.1111/j.1467-7652.2008.00356.x; Zolla-Pazner, S., Identifying epitopes of HIV-1 that induce protective antibodies (2004) Nat Rev Immunol, 4, pp. 199-210