Visualizing Heparan Sulfate Expression within Secondary Lymphoid Organs of Mice

Heparan sulfate (HS) is a glycosaminoglycan found in the extracellular matrix as well as on the surface of most cells. It has been shown to affect ligand-receptor interactions, cell motility, and cell adhesion. Despite the importance of heparan sulfate, its role in B cell biology is still relatively unknown. Unpublished experiments have shown that heparan sulfate expression on B cells is induced by the cytokine type 1 interferon (IFN-1). Furthermore, expression of heparan sulfate on B cells and within lymph nodes affects lymphocyte processes such as B cell motility and ligand-receptor interactions, both of which are essential for an enhanced immune response. Because B cells play a critical role in the humoral immune response by producing antibodies, heparan sulfate may be a key player in B cell-mediated immunity. Immunofluorescence of lymph nodes may illustrate specifically where heparan sulfate is expressed on B cell follicles and elsewhere in the lymph node. We utilized mice injected with PBS (control) and PolyI:C, an inducer of IFN-1. Mice injected with PolyI:C express heparan sulfate on B cells and are utilized to assess heparan sulfate expression within the secondary lymphoid organs. The results from these experiments, however, have displayed inconclusive due to difficulties in establishing an accurate positive control and in interpretation of staining. Further studies may suggest how the expression of heparan sulfate in specific regions of murine secondary lymphoid organs may influence B cell dynamics. These studies may demonstrate a vital role of heparan sulfate expression within secondary lymphoid organs in immune responses.