Am. Robinson et al., THE SPECIFICITY AND AFFINITY OF IMMUNOLIPOSOME TARGETING TO ORAL BACTERIA, Biochimica et biophysica acta. Biomembranes, 1369(2), 1998, pp. 278-286
Immunoliposomes have been prepared using antibodies raised to an antig
enic determinant on the cell surface of the oral bacterium Streptococc
us oralis (S. oralis) in an investigation of their potential to reduce
dental plaque. The N-succinimidyl-S-acetylthioacetate (SATA) derivati
ve of the antibodies were conjugated through the reactive m-maleinidob
enzoyl-N-hydroxysuccinimide (MBS) derivative of dipalmitoyl-phosphatid
ylethanolamine (DPPE) incorporated into liposomes. The degree of antib
ody conjugation to the liposomes was controlled by the percentage of D
PPEMBS incorporated into the liposomes. The chemical modification of t
he antibodies did not affect the ability of the antibodies to bind to
a S. oralis biofilm. However, the affinity of the immunoliposomes for
S. oralis was much lower than that of the free antibody. The anti-oral
is antibodies were highly specific for S. oralis. The anti-oralis immu
noliposomes showed the greatest affinity for S. oralis, when targeted
to a range of different oral bacterial biofilms. The immunoliposome ta
rgeting affinity for S. oralis was largely unaffected by the number of
antibodies conjugated to the liposomal surface or by the net charge o
f the liposomal lipid bilayer. The immunoliposomes showed a greater af
finity for S. oralis than 'naked' (bearing no antibody) liposomes. How
ever: positively charged liposomes, incorporating stearylamine, adsorb
ed to S. oralis with greater affinities than the immunoliposomes, The
immunoliposomes appeared to be physically stable over a period of 18 m
onths, as judged by particle-size measurements. (C) 1998 Elsevier Scie
nce B.V.