Publications

Drug targeting can be achieved by coupling drugs or their carriers to affinity molecules, mostly antibodies (Abs), which recognise specific protein targets. However, most proteins are not expressed in an exclusive configuration but as various isoforms. Hence, selected targeting molecules may fail to target with enough efficiency in clinical trials, which is overlooked. We illustrate this by targeting intercellular adhesion molecule 1 (ICAM-1), a cell-surface protein overexpressed in many pathologies. Most ICAM-1 targeting studies used Ab R6.5, which binds ICAM-1 domain 2 (D2). Yet, literature and our data show that D2 is frequently absent among ICAM-1 isoforms. We thus produced a battery of five new Abs (B4, B6, B11, C12 and G2) and tested their ability to recognise both full-length and -D2 ICAM-1. In solution, all Abs recognised both ICAM-1 forms (from 5.3 x 1011 to 4.2 x 1012 sum intensity/well). Coating them on nanocarriers (NCs) rendered G2 specific against -D2 ICAM-1 (4.2 x 106 NCs/well) while other Abs kept their dual recognition (from 6.4 x 106 to 2.2 x 107 NCs/well). All Abs induced NC intracellular uptake in respective cells (from 42% to 85%) and displayed good cross-species reactivity (from 4.4 x 1011 to 2.6 x 1012 sum intensity/well). These Abs represent valuable tools to target ICAM-1 and illustrate a new targeting paradigm that may improve classical strategies.

JTD Keywords: Adhesion, Antibody-targeted nanocarriers, Cross-species reactivit, Design, Domai, Endothelial delivery, Enlimomab, Icam-1, Icam-1 isoforms, Intercellular adhesion molecule 1, Nanocarriers, Nanoparticles, New recombinant antibodies, Pecam-1, Targeting and intracellular trafficking

Citrus tristeza virus (CTV) causes one of the most destructive viral diseases of citrus worldwide. Generation of resistant citrus genotypes through genetic engineering could be a good alternative to control CTV. To study whether production of single-chain variable fragment (scFv) antibodies in citrus could interfere and immunomodulate CTV infection, transgenic Mexican lime plants expressing two different scFv constructs, separately and simultaneously, were generated. These constructs derived from the well-referenced monoclonal antibodies 3DF1 and 3CA5, specific against CTV p25 major coat protein, whose mixture is able to detect all CTV isolates characterized so far. ScFv accumulation levels were low and could be readily detected just in four transgenic lines. Twelve homogeneous and vigorous lines were propagated and CTV-challenged by graft inoculation with an aggressive CTV strain. A clear protective effect was observed in most transgenic lines, which showed resistance in up to 40-60% of propagations. Besides, both a delay in symptom appearance and attenuation of symptom intensity were observed in infected transgenic plants compared with control plants. This effect was more evident in lines carrying the 3DF1scFv transgene, being probably related to the biological functions of the epitope recognized by this antibody. This is the first report describing successful protection against a pathogen in woody transgenic plants by ectopic expression of scFv recombinant antibodies.

JTD Keywords: CTV control, Immunomodulation, Plantibodies, Recombinant antibodies, Transgenic citrus