| First Author | Huntoon KM | Year | 2013 |
| Journal | Mol Immunol | Volume | 55 |
| Issue | 3-4 | Pages | 345-54 |
| PubMed ID | 23548836 | Mgi Jnum | J:202142 |
| Mgi Id | MGI:5517534 | Doi | 10.1016/j.molimm.2013.03.008 |
| Citation | Huntoon KM, et al. (2013) A unique form of haptoglobin produced by murine hematopoietic cells supports B-cell survival, differentiation and immune response. Mol Immunol 55(3-4):345-54 |
| abstractText | Haptoglobin (Hp), an acute phase reactant and major hemoglobin-binding protein, has a unique role in host immunity. Previously, we demonstrated that Hp-deficient C57BL/6J mice exhibit stunted development of mature T- and B-cells resulting in markedly lower levels of antigen-specific IgG. The current study identified leukocyte-derived pro-Hp as a relevant mediator of an optimal immune response. Reconstitution of Hp-/- mice with Hp+/+ bone marrow restored normal immune response to ovalbumin. Furthermore, transplanting a mixture of bone marrow-derived from B-cell-deficient and Hp-deficient mice into Rag1-/-/Hp+/+ recipients resulted in mice with a defective immune response similar to Hp-/- mice. This suggests that Hp generated by the B-cell compartment, rather than by the liver, is functionally contributing to a normal immune response. Leukocytes isolated from the spleen express Hp and release a non-proteolytically processed pro-Hp that uniquely differed from liver-derived Hp by not binding to hemoglobin. While addition of purified plasma Hp to cultured B-cells did not alter responses, pro-Hp isolated from splenocytes enhanced cellular proliferation and production of IgG. Collectively, the comparison of wild-type and Hp-deficient mice suggests a novel regulatory activity for lymphocyte-derived Hp, including Hp produced by B-cells themselves, that supports in vivo survival and functional differentiation of the B-cells to ensure an optimal immune response. |
