Jm. Danforth et al., MACROPHAGE INFLAMMATORY PROTEIN-1-ALPHA EXPRESSION IN-VIVO AND IN-VITRO - THE ROLE OF LIPOTEICHOIC ACID, Clinical immunology and immunopathology, 74(1), 1995, pp. 77-83
Lipoteichoic acid (LTA), a component of the cell wall of most gram-pos
itive bacteria, has been shown to play a significant role in the initi
ation and progression of bacterial infection. However, little is known
of its position in the cytokine network involved in the induction and
perpetuation of inflammation. In this study, we assessed whether the
macrophage activating and chemotactic cytokine macrophage inflammatory
protein-1 alpha (MIP-1 alpha) was expressed in the setting of localiz
ed gram-positive infection. Furthermore, we determined whether LTA pur
ified from either Staphylococcus aureus or Streptococcus pyogenes coul
d induce the expression of MIP-1 alpha mRNA and protein from human blo
od monocytes. Immunohistochemical staining of human endocardial sample
s obtained from patients with acute S. aureus endocarditis revealed ce
ll-associated MIP-1 alpha expression by neutrophils, macrophages, and
fibroblasts. Treatment of human peripheral blood monocytes in vitro wi
th LTA isolated from either S. aureus or S. pyogenes resulted in both
the time- and dose-dependent expression of MIP-1 alpha mRNA. Similarly
, staphylococcal and streptococcal LTA induced the dose-dependent prod
uction of MIP-1 alpha protein after 24 h in culture. These studies sug
gest that LTA may play an important role in triggering the recruitment
and activation of leukocytes that characterizes the host response to
gram-positive bacterial invasion. (C) 1995 Academic Press, Inc.