CD4 and infection: At 4 weeks after implantation, increased numbers of total cells (Fig. 6A), CD3+ T cells (Fig. 6B), CD3+CD4+ helper T cells (Fig. 6C), F4/80 macrophages (Fig. 6F), M1 macrophages (Fig. 6G), and neutrophils (Fig. 6J) were present in the infection-only group compared to infections treated with lysostaphin-delivering hydrogels and both sterile control groups.