Antibodies are crucial, not only for treating tumors and infections. Sometimes, however, the immune reaction they trigger can be too strong and end up causing more damage, for example in the case of people infected with Covid-19. Problems such as these can often be avoided by finetuning antibodies, as Prof. Dr. Falk Nimmerjahn from Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) and two of his colleagues in the Netherlands and in the UK have now reported in the journal Nature Immunology.