Neutrophils - Innate immunity

N are pivotal effector cells of innate immunity representing the first line of defense against aggression. They are the first cells to arrive at the site of the aggression, where they can directly eliminate the invading microorganisms. Their activation and recruitment into peripheral tissues is indispensable for host defense. They recognize antigens through membrane receptors which are expressed during their maturation and activation. With aging, there are alterations of the receptor by driven functions of human neutrophils as a decrease in the functional changes in signaling elicited by specific receptors. The analysis of CXCL8 cultivated-neutrophils showed elastase (ELA) secretion, but neither myeloperoxidase (MPO) activity nor production of IL-6, IL-10, GM-CSF by neutrophils from elderly compared with young individuals. Differences were detected when neutrophils from elderly were cultivated in the presence of only LPS or LPS plus CXCL8. Data also showed significant decreasing of CD16+ and CD64+ neutrophils from elderly when compared with young humans. CD32+ neutrophils were increased when compared with young group. These data indicate that elderly neutrophils are able to activate and respond to antigens. However, CD16 and CD64 expression is neglected on neutrophils and it might contribute to immunosenescence markers.