HER2+ invasive breast cancer (IBC) patients with residual disease following neoadjuvant chemotherapy have an anti-HER2 Type 1 T helper (Th1) cell immune deficit and a significant risk of recurrent disease. It has been shown that anti-HER2 CD4+ T-cell responses incrementally decrease along the breast cancer continuum - a robust response in healthy donors and patients with benign disease, a depressed response in patients with HER2+ ductal carcinoma in situ, and a nearly absent response in patients with HER2+ IBC. This invention relates to a method of creating a microenvironment for culture expansion of T cells. The expanded T cells can be used for a variety of therapeutic and research purposes.