Studies on immune responses in afferent and efferent lymph of lymph nodes draining the tissues have contributed to the concept that primary immune responses are generated in the lymph nodes with a delay before antigen-specific effector cells arrive at the affected tissue.
Lightning strikes the ground approximately 25 million times each year in the U.S. According to the NWS, the chance of an individual in the U.S. being killed or injured during a given year is one in 240,000. Assuming an average life-span of 80 years, a person's odds over their lifetime becomes one in 3000.
The man who survived being struck by bolt 7 times and then commits suicide. The odds of being struck by lightning for an ordinary person over the period of 80 years have been roughly estimated as 1 in 3000. Yet, between 1942 and 1977, U.S. park ranger Roy Sullivan defied all odds after being hit by lightning on seven different occasions, surviving all of them.