C-reactive protein is protective against Streptococcus pneumoniae infection in mice.

Abstract

C-reactive protein (CRP) has several properties that suggest that it may function as a bacterial opsonin. CRP shows binding reactivity with pneumococcal C-polysaccharide, the cell wall carbohydrate of Streptococcus pneumoniae. In this study we have demonstrated protection of mice against serotypes 3 and 4 of S. pneumoniae infection by a single prior injection of CRP. This effect was seen both in mice that lacked antibody to phosphocholine and in normal mice. Thus the opsonic properties of CRP previously described may be related to protection against pneumococcal infection.

Serum Amyloid P Component Binds to Fcγ Receptors and Opsonizes Particles for Phagocytosis

“…To our knowledge, this is the first description of the opsonic activity of SAP. The phagocytosis of a fungal cell suggests that SAP could be involved in protection of the host from infection similar to CRP, which has been demonstrated to protect mice from infection with Streptococcus pneumoniae (35,36). Experiments designed to examine this possibility are currently in progress.…”

The Phosphocholine-binding Pocket on C-reactive Protein Is Necessary for Initial Protection of Mice against Pneumococcal Infection

“…Therefore mice are used to explore the in vivo functions of human CRP. In mouse models of infection, passively administered human CRP has been shown to be protective against lethal pneumococcal infection, as determined by increased survival of and decreased bacteremia in the infected mice (24,25). Interestingly, CRP was most effective in protecting mice from infection only when injected within the range of 6 h before to 2 h after administering pneumococci into mice (26).…”

C‐reactive protein impairs human CD14+ monocyte‐derived dendritic cell differentiation, maturation and function

“…CRP may be protective against the development of autoimmunity [12] and anti-inflammation [13] in mice, however human CRP does not protect mice against lipopolysaccharide (LPS) lethality [14]. Additionally, CRP has been shown to be protective against bacterial infections [15], a variety of inflammatory conditions and various mediators of inflammation [16]. Gershov et al demonstrated that CRP may interact with apoptotic cells and promote noninflammatory clearance of apoptotic cells [17].…”