They also express T cell activation markers, even (and to a great extent) in germ free mice, hence they appear to develop to become a natural memory cell population based on some type of internal antigen (s). (lji.org)
A Comparative Study on Platelet Activation Markers Between Continuous and Intermittent Exercise Training Programs in Healthy Males (thejh.org)
For example, one could stain for cellular markers and activation markers to infer the activity status of T lymphocytes (ptglab.com)