The disease control agency regards environmental microbiology as one of its strengths, Dr. Gerberding said, but it soon learned that the discipline had a long way to go when it came to anthrax -- in particular, sampling the air for spores, disinfecting an area and monitoring it for spores and particles that might escape when envelopes are put under mechanical pressure.
It was a decision based on the mistaken -- and easily testable -- assumption that anthrax could not escape a sealed envelope.
Interestingly, envelope escape variants were detected due to G145R, D144DE and P142LP mutations.
One official said, however, that the agency had not initially been made aware that the anthrax particles in the Daschle letter were small enough to have escaped a sealed envelope.
And this morning, in his radio address from Camp David, he stopped just short of acknowledging that the White House had underestimated the threat to ordinary Americans two weeks ago, when it listened to experts who believed that anthrax could not escape from sealed envelopes.
While the cell viability checks described above indicate that cell lysis due to the trypsin treatment is unlikely, it is conceivable that cell lysis in the cell culture prior to the trypsin treatment may have released intracellular proteins that somehow have re-associated with the cell envelope and escaped proteolytic degradation [ 26, 37].
Tragically, it turned out that the tiny anthrax spores could readily escape through the pores of an envelope as it passed through postal machinery, and the primary victims were postal workers.
Moreover, selection would be also more likely to be operating on env than on the other genes because the viral envelope must evolve to escape immune detection, thus making recombination a likely source of adaptative phenotypes.
Soon after HIV infection, the immune system attacks the virus, which then escapes immune recognition by mutating its surface envelope protein, gp140.
We isolated a virus-neutralizing antibody lineage that targeted an envelope region (loop D) and selected virus escape mutants that resulted in both enhanced bnAb lineage envelope binding and escape mutant neutralization traits associated with increased B cell antigen drive.
