Gitta obtained her PhD in Biology at the University of Mainz and then did postdoctoral studies in London and Cambridge, followed by a postdoc at the Cancer Research Institute in Heidelberg. In 1985 she became a member of the Basel Institute for Immunology where she stayed until 1991. Her time at the Basel Institute shaped her career significantly, as in this institute young researchers were given complete freedom to choose their research direction thus gaining independence earlier than would otherwise have been possible.
In 1991 Gitta became a group leader in the Division of Molecular Immunology of the Medical Research Council National Institute for Medical Research (now part of the Francis Crick Institute). Her research initially focused on immune tolerance using T cell receptor transgenic mouse models. Following on her interest turned to immunological memory focusing on CD4 memory T cells, their generation and survival.
Gitta's lab got involved in infection research following their discovery of the differentiation factors for Th17 generation. Inflammation and infection have been a focus of their research since. More recently they discovered the importance of the transcription factor aryl hydrocarbon receptor (AhR), an environmental sensor, in the immune system.
Gitta obtained an ERC Advanced Investigator grant in 2009 to study physiological functions of AhR and in 2013 was awarded a Wellcome Senior Investigator Grant that will continue and expand the investigation of AhR in innate and adaptive immune cells. She became a Fellow of the Academy of Medical Sciences in 2005, an EMBO fellow in 2008 and a Fellow of the Royal Society in 2013.