Antigen targeted to secondary lymphoid organs via vascular cell adhesion molecule (VCAM) enhances an immune response.

The localisation of antigen within secondary lymphoid organs can significantly increase the immune response. Using the monoclonal antibody M/K 2.7, which recognises murine vascular cell adhesion molecule (VCAM), we have shown antigen accumulation within organs of the secondary lymph such as the draining lymph nodes and spleen. Similar accumulation was not apparent in other, non-lymphatic organs. We then compared the immune response to antigen targeted to secondary lymphoid organs, via VCAM recognition, with untargeted antigen. The model antigen used, rat IgG1, was shown to be a weak murine immunogen, not eliciting any measurable antibody or cellular response. However, the same antigen targeted to VCAM, was shown to elicit an IgG1 antibody response and T cell proliferation, also marked by IFNgamma expression. These results confirm the effectiveness of targeting antigen to secondary lymphoid organs in enhancing an immune response and identify VCAM as a useful target.