Antibodies against viral proteins can be produced effectively in response to the increased uptake of alpha 2-macroglobulin:viral protein conjugate by macrophages.

We have previously shown that foreign antigens conjugated to alpha 2-macroglobulin (alpha 2M) were effectively taken up by macrophages, which was followed by a remarkable increase in the proliferation of immune T cells. We present in this report that the production of antibodies against viral proteins can also be effectively achieved when viral proteins were conjugated to alpha 2M and fed to the in vitro immune system. Proteins derived from Kirstein murine sarcoma virus (Ki-MSV) were partially purified by gel chromatography and conjugated to alpha 2M by the action of proteinases. Viral proteins conjugated to alpha 2M were taken up by thioglycolate-induced murine peritoneal exudate cells (PEC) more effectively than the free viral proteins. Murine spleen cells were then added to PECs fed with free viral proteins or with alpha 2M: viral protein conjugates, and the cell mixtures were incubated for five days. Each culture medium was then assayed for a specific antibody production by enzyme-linked immunosorbent assay (ELISA). Figures based on such assays revealed that the production of antibodies against viral proteins was ten times higher when the proteins were fed to macrophages in conjugated forms with alpha 2M.