Eta-1 (osteopontin): an early component of type-1 (cell-mediated) immunity. Ashkar S et al.
Cell-mediated (type-1) immunity is necessary for immune protection against most intracellular pathogens and, when excessive, can mediate organ-specific autoimmune destruction. ... A phosphorylation-dependent interaction between the amino-terminal portion of Eta-1 and its integrin receptor stimulated IL-12 expression, whereas a phosphorylation-independent interaction with CD44 inhibited IL-10 expression. These findings identify Eta-1 as a key cytokine that sets the stage for efficient type-1 immune responses through differential regulation of macrophage IL-12 and IL-10 cytokine expression.
Phosphorylation-dependent interaction of osteopontin with its receptors regulates macrophage migration and activation. Weber GF et al.
Neutrophil-independent macrophage responses are a prominent part of delayed-type immune and healing processes and depend on T cell-secreted cytokines. An important mediator in this setting is the phosphoprotein osteopontin, whose secretion by activated T cells confers resistance to infection by several intracellular pathogens through recruitment and activation of macrophages. ... These data, taken as a whole, indicate that the activities of distinct osteopontin domains are required to coordinate macrophage migration and activation and may bear on incompletely understood mechanisms of delayed-type hypersensitivity, wound healing, and granulomatous disease.