Instead, Montagnier extracted the proteins from the umbilical cord lymphocytes and placed them on a strip according to their molecular weight. He then exposed the strip to BRU's serum as well as serum from a healthy donor and normal goat serum and from a goat immunised with HTLV-1. Many proteins reacted.

He repeated the experiment with the proteins which banded at 1.16g/ml. Only p24, p41, p80 reacted. He made no comment on p80, but Gallo later showed it to be a cellular protein.

Because p41 (which Montagnier called p45) reacted with all the sera and because a ubiquitous cellular protein, actin, has a molecular weight of 41,000, he said that p41 was actin which "contaminated" his "purified virus".

Because they found p24 to react only with BRU's serum, they assumed that p24 is an HIV protein and the antibodies specifically induced by HIV.

However, from an antibody-antigen reaction is impossible to determine the origin of even one reactant. Yet Montagnier claims to have determined the origin of both.

There is ample evidence which shows that the 1.16g/ml material contains both actin an another ubiquitous cellular protein, myosin, whose light chains have molecular weight of 24,000.

Montagnier himself showed that AIDS patients and those at risk have high levels of antibodies to both actin and myosin.