Postnatal functional maturation of blood phagocytes in pig

Developmental changes of functional ability of peripheral blood phagocytes from days 1 to 100 of life were investigated.Luminol enhanced chemiluminiscence was used to establish the ability of phagocytes to produce reactive oxygen species (ROS). Simple superoxide anion production was determined by spectrophotometrical measurement of cytochrome c. Activity of surface aminopeptidase N was assessed by spectrophotometrical measurement of l-alanine-p-nitroanilide. Flow cytometric measurements of CD18 and CD45 expression were performed.The ROS production per 0.5 μl of blood did not show any trend; however, the values recalculated per 500 granulocytes had a decreasing course. The most noteworthy increase in production of superoxide anion occurred between days 17 and 26. Activity of aminopeptidase N decreased during the first 4 weeks. Expression of CD18 and CD45 intensively increased from days 1 to 14 with gradual decrease by day 100. Natural immunity develops during the early postnatal life and seems to be influenced by exposure of the organism to environmental antigens.