[Effects of the spaceflight factors on the immune system]

The paper summarizes the main trends and milestones of space immunology starting with initial ground-based investigations with animals to recent experiments in piloted and automatic space vehicles data of which have been highlighted in numerous publications. There is a brief description of lines and results of investigations with participation of cosmonauts, and using laboratory animals and cell cultures. The author dwells upon the present-day notion of immune responses to extreme conditions and future topics of investigations.