Modulation of CD28 in vivo does not modify antibody responses.

Rats were immunized intraperitoneally with 10 μg DNP-OVA without adjuvant (A) or subcutaneously with 50 μg KLH in CFA (B). Recipients received intraperitoneally 1 mg control IgG or modulating anti–rat CD28 JJ319 or 0.5 mg CTLA4 immunoglobulin at days 0, 2, 4, and 6. Isotyping of the specific antibody responses was performed by enzyme-linked immunosorbent assay at day 12 (A) or 18 (B). *indicates significative at P < .05.