We investigated the ontogenic development of macrophage functions which are important in the expression of host defense against @entity281 by @entity5125 . Macrophage functions, including accumulation in response to local stimuli, chemotaxis in vitro, and intracellular killing, as well as number of macrophages, were examined by using @entity19 1, 2, 3, 4, and 8 weeks old. The number of peritoneal macrophages was extremely low in younger @entity19 even when their body weights were taken into consideration. Macrophage accumulation in response to infectious stimulus with viable listeria was poor in younger @entity19 and showed an age-dependent development. In younger groups, chemotaxis in vitro was as immature as chemotaxis in vivo. @entity69799 - and 2-week-old @entity19 , macrophages did not show any intracellular killing activity against @entity5125 , but killing was observed in @entity19 over 3 weeks of age. These functions developed in an age-dependent manner and reached the 8-week-old adult level after the @entity19 were 4 weeks of age. In adult @entity19 , these macrophage functions were shown to be enhanced after immunization with viable listeria; however, such an immunization-induced enhancement was very poor in the younger groups of @entity19 . Protection judged by mortality and in vivo bacterial growth was weaker in the younger groups against both primary and secondary challenges. In vivo protection against @entity5125 seemed to develop in the same age-dependent manner as the development of macrophage functions. These results indicate that age-dependent immaturity of macrophage functions mainly comprises the age-dependent immaturity of protection against @entity5125 .

Ontogeny of macrophage-mediated protection against XXXX .

@entity19 :: ('10090', 'Species') :: ['mice'] @entity281 :: ('MESH:D007239', 'Disease') :: ['infection'] @entity69799 :: ('16258(Tax:10090)', 'Gene') :: ['In 1'] @entity5125 :: ('1639', 'Species') :: ['Listeria monocytogenes', 'L. monocytogenes']
@entity5125 :: (1639,Species) :: ['Listeria monocytogenes']
