Effects of preventative administration of the anti-α4 Ab on serum IgG2b levels in 5TGM1/luc myeloma-bearing mice. Monoclonal IgG2b was measured by sandwich ELISA as described in “Materials and methods.” Data are mean ± SEM of 2 separate experiments (n = 10 × 2 = 20). ^*Significantly different from untreated group. ^**Significantly different from control IgG group.