HCV particles are 50–80 nm in diameter [19] and contain classical viral components such as a
single-stranded RNA genome, core and the envelope glycoproteins, E1 and E2 [27]. HCV genome
interacts with the core protein to form the nucleocapsid that is surrounded by a lipid membrane, called
the viral envelope, in which are anchored the envelope glycoproteins. The exact nature of the interactions
involved between HCV virion components and the lipoprotein remains poorly understood. One
possibility could be that lipoproteins peripherally associate with canonical viral particles via interaction
between apolipoproteins and HCV envelope lipids or proteins [28]. Alternatively, HCV virion could be
a hybrid particle composed of a virion moiety and a lipoprotein component [29]. This latter hypothesis
is reinforced by the observation that recombinant HCV envelope glycoproteins, expressed in the absence
of other viral components, can be secreted along with triglyceride rich lipoproteins by differentiated
intestinal Caco-2 cells [30]. These recombinant envelope glycoproteins were shown to be associated
with lipoproteins containing apoB. More recently, it has also been reported that HCV envelope
glycoproteins directly interact with apoE and apoB during HCV morphogenesis [31,32]. Whatever the
mode of association, HCV interaction with lipoproteins could contribute to the shielding of the viral
envelope glycoproteins from the host antibody neutralizing response and could explain the poor
detection or availability of HCV glycoproteins at the virion surface [19,24,33].