[T]he vaccine stimulated antibodies that recognized HIV as well as microbes commonly found in the intestinal tract, part of the body’s microbiome.
…but these antibodies did not neutralize HIV.
If the antibodies created recognise the material expected to appear in intestinal dysbiosis, how do you know that those antibodies are actually for that and not ‘HIV’? Cross-reactive antibodies are not uncommon, but they should expectedly target what they’re intended for as well as other things.
In people with acute HIV infection, the majority of anti-HIV antibodies target gp41 but do not neutralize the virus. Prior research suggests that these naturally occurring antibodies likely originate from immune cells in the intestinal tract previously stimulated by the microbiome, leading to polyreactivity.