The important point is that Montagnier’s experiments do not prove the existence of a retrovirus because, as Montagnier himself admits, all the phenomena he described are non-specific for retroviruses, or even for viruses.

Suffice it to say that two of the best known retrovirologists say:

"Particles and proteins, could reflect non-viral material altogether."

"Release of virus-like particles morphologically and biochemically resembling type-c virus but apparently lacking the ability to replicate have been frequently observed from leukaemic tissue."

Proof for the existence of a retrovirus requires purification (isolation) of particles, analysis of their constituents, introduction of pure particles into uninfected cells followed by a second analysis to prove that the particles produce identical progeny (see introduction). Only then can one claim to have proven a virus exists.