RESUMO
The receptor properties of H1 and H2 influenza viruses (IV), isolated from duck, pig and man were studied by using the natural and synthetic sialoglycoconjugates. It was shown that viruses, isolated from different hosts, adapt themselves to the host cell receptors. The IV affinity was increasing to 6'sialy(N-acetyllactosamine) in proportion as amino acids (in positions 138, 190, 194 and 225), which are for avian IV, were increasingly replacing. Some of the porcine viruses display adaptation to the human receptor, i.e. 6'sialy(N-acetyllactosamine), however, all tested porcine influenza viruses, belonging to different evolution branches, acquired even more affinity to sulphated and fucozyled derivatives of 3'sialy(N-acetyliactosamine)-(Neu5AC alpha 2-3 g AL beta 1-4(fUC alpha 1-3)(6-sulfo)GlcNAc beta).