J Immunol 1989; 5(1): 15. By two independent assays (T cell prolifera-tion and interleukin-2 secretion), presenta-tions of rabbit anti--mouse IgM antibody (RAMIgM) and rabbit immunoglobulin(RIg) by Blymphocytes and macrophages were investigatedwith RIg-specific T cell line. The resultsshowed that RAM IgM was presented at con-centrations 10~(-3)-fold lower than RIg in T cellproliferation when B lymphocytes were used J Immunol 1989; 5(1): 15. By two independent assays (T cell prolifera-tion and interleukin-2 secretion), presenta-tions of rabbit anti--mouse IgM antibody (RAMIgM) and rabbit immunoglobulin(RIg) by Blymphocytes And macrophages were investigatedwith RIg-specific T cell line. The resultsshowed that RAM IgM was presented at con-centrations 10~(-3)-fold lower than RIg in T cellproliferation when B lymphocytes were used