One of the AIDS causing viruses, HIV-1, uses a trick that has not been seen in other viruses to escape from the immune system, displacing sugar molecules with layers of external proteins, so that the areas of binding of antibodies are covered and the antibodies cannot adhere to the virus. Normally, to disappoint the immune system, viruses alter the sequence of proteins they contain on the outside. On this occasion they have seen that HIV-1 is able to take one more step. The research has been published in the journal Nature.