| First Author | Velez CD | Year | 2009 |
| Journal | Immunology | Volume | 127 |
| Issue | 1 | Pages | 73-82 |
| PubMed ID | 18778282 | Mgi Jnum | J:155663 |
| Mgi Id | MGI:4414931 | Doi | 10.1111/j.1365-2567.2008.02924.x |
| Citation | Velez CD, et al. (2009) Type I Streptococcus pneumoniae carbohydrate utilizes a nitric oxide and MHC II-dependent pathway for antigen presentation. Immunology 127(1):73-82 |
| abstractText | Some pathogenic bacteria form thick capsules that both block immune responses through inhibition of complement deposition and phagocytosis and stimulate a weak response resulting from a lack of T-cell involvement. Contrary to this model, capsular polysaccharides from 23 serotypes of Streptococcus pneumoniae have been successfully used in a multivalent vaccine in the absence of a carrier protein. Furthermore, type I pneumococcal polysaccharide (Sp1) has been shown to activate T cells in vivo and in vitro via an uncharacterized mechanism. In the present report, we demonstrate that Sp1 utilizes the major histocompatibility complex (MHC) class II pathway in antigen-presenting cells (APCs) for processing and presentation. APCs internalize and process Sp1 through a nitric oxide-dependent mechanism and, once inside the cell, it associates with MHC II proteins in an H-2M-dependent manner that leads to in vivo T-cell activation. These results establish that Sp1 activates T cells which can lead to abscess formation in mice through an H-2M-dependent polysaccharide antigen presentation pathway in APCs, potentially contributing to pneumococcal polysaccharide vaccine efficacy through the recruitment of T-cell help. |
