Chapter 2 - Innate Immunity at Birth: Implications for Inflammation and Infection in Newborns

Abstract

The development of immunity at birth is vital and it involves several complex mechanisms. Since prior antigenic experience is limited, the adaptive immunity requires time for development. The newborns depend heavily on their innate immunity for survival during early life. The microbiome with the commensal flora contributes to the development of immunity in newborns. Maternal antibodies at the various mucosal surfaces are the primary checkpoints which provide immunity in the neonatal period. The reduced chemotaxis, phagocytosis and sustained activation of neonatal neutrophils and monocytes increase the susceptibility of newborns to infection. The quantitative and qualitative characteristics of dendritic cells are subset specific and their varied ontogeny and functions impair antigen presentation and reduce the vaccine responsiveness in early life. The natural killer cell functions like degranulation and release of lytic factors are reduced in early life which makes the newborns more prone to viral infections. Dietary limitation during lactation has shown to modify the functions of immune cells and increase the susceptibility to pathogenic invasion. Dietary supplements like lactoferrrin have shown to increase the levels of immunoglobulins and improve the mucosal and systemic immune response in early life.