Recombinomics Commentary 23:54
December 24, 2009
The recently released HA sequences from fatal cases in Mexico has identified a cluster(25M and 40M) with D225G and D225N. Both isolates, A/Mexico/InDRE50625/2009 and A/Mexico/InDRE50617/2009) have mixed signals and were collected within a day of each other from San Lois Potosi, Mexico. They are the first two isolates from patients in Mexico with both receptor binding domain changes, D225G and D225N, although the same combination was found in a swine sequence, A/swine/4/Mexico/2009, from an outbreak in the adjacent province of Queretaro in April. The only other reported human sequence with D225G and D225N was from a fatal case in Utah, A/Utah/42/2009, who died July 28.
Concern about the association of receptor binding domain changes D225G and D225N began to emerge when sequences from cases in Brazil were released. Two Sao Paulo sequences had D225G and both were from fatal cases. Two more Sao Paulo sequences had D225N and both cases were also fatal. Moreover, D225G was also found in fatal cases from 1918 and 1919, and the sequence change led to receptor binding changes that targeted receptor with gal 2,3 linkages, such as cells in the lung.
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