<unk> s are a specific type of infection-fighting T cell (also known as a T lymphocyte) that can recognize foreign invaders such as bacteria or viruses, that were encountered during a prior infection or vaccination. At a second encounter with the invader,<unk> s can reproduce to mount a faster and stronger immune response than the first time the immune system responded to the invader. This behaviour is utilized in T lymphocyte proliferation assays, which can reveal exposure to specific antigens.
Memory T cell
Cytotoxic T cell
Reactive lymphocyte
Dendritic cell
Follicular dendritic cells
B cell
Plasma cell
Monocyte