Liposomes antibody conjugates with

K., Abe, O., and Saito, K. (1987). Antitumor effect of adria-mycin entrapped in liposomes conjugated with anti-human alfa-fetoprotein monoclonal antibody, Cancer Res., 47, 4471-4477. 

Similar to drugs, liposomes could be conjugated with antibodies, peptides and genes, among others, to expand the existing range of analytical and non-analytical applications of US. 

Onuma, M. Yasutomi, Y. Yamamoto, M. Watarai, S. Yasuda, T. Kawakami, Y. Antitumor effect of adriamycin entrapped in liposomes conjugated with anti-bovine tumor antigen monoclonal antibody in leukemic cows. Zentralbl. Veterinarmed. 1989, 36, 139-147. 

Mix lipids (as showing on Table 2 for preparing 30 mg of appropriate sample) in a 250 mL round bottom flask according to the desired lipid molar ratio. For liposomal conjugation with an antibody or similar targeting agent, MPB-PE or PEG-PE is to be added. 

For antibody conjugation, the liposomal phospholipid concentration needs to be determined using Bartlett assays (94) (see Subheading 3.3). Both antibodies of the matched set should be conjugated to liposomes to determine which serves as the better detection antibody. Liposomes should be mixed with antibodies with the latter at 0.05 mol% of the total lipid input. Then, just before use, dilute EDC to a concentration of lOOmg/mL with 0.1 M MES buffer, pH 4.65 then add five molar equivalents (based on total W-glutaryl DPPE lipid input) to the liposome/ antibody mixture. Note that EDC is very hydroscopic - use care... 

Tremendous efforts have been made to overcome these challenges, cationic liposome and positively charged polymers are currently being used as the most common method to complex with negatively charged siRNA for systemic delivery [30, 36]. Other in vivo delivery approaches include conjugation with cholesterol, aptamer, peptide complexation with antibody-protamine fusion protein or encapsulation in cyclodextrin nanoparticles [35, 37-39]. 

Naturally, liposomes as such are not unique in this context. Instead, the same approach can be used for other PEO-modified colloidal drug carriers, e.g. copolymer micelles. For example, Kabanov et al. have demonstrated specific targeting of fluorescein isothiocyanate solubilized in PEO-PPO-PEO block copolymer micelles conjugated with antibodies to the antigen of brain glial cells (a2-glycoprotein) (83, 84). Furthermore, incorporation of haloperidol into such micelles was found to result in a drastically improved therapeutic effect in mice, as inferred from horizontal mobility and grooming frequency studies. 

We also explored using the attached hposomes for detection of BG spores. Early experiments suggested that attached liposomes composed of diacetylene fatty acids (1) were more responsive to the spores than ones based on diacetylene ethanol amides (2). The liposomes were prepared with 20% of 11 incorporated so antibodies could be conjugated via the BS3 linker. We compared the performance of attached fatty acid hposomes in three different buffer... 

Figure 10. Ricin detection with poly(60% 10/20% POPC/10% 11/10% DPPT) attached liposomes with 0.5% 1 incorporated and anti-ricin antibodies conjugated via BS3 O.lngricinj/) ), Ing ricin (Qj lOngricin (A) lOOngricin (O) lOOng bovine IgG (9). 100 pL/well. Control subtracted.

Figure 11. BG detection with poly(70%> 6,8-PCDA/20%PCD-NH2/l 0% DPPT) attached liposomes with 0.5% M incorporated and anti-BG antibodies conjugated via BS3. (A) lOmM NaPO4/150mM NaCl (B) 10mM)/100mM CaCl2. 10. spores/well (Ol 10 spores/well (A) 10 spores/well (9). lOOpL/well. Control subtracted.

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