Specific cell-mediated immune recognition of penicillin conjugated to autologous albumin through amino or sulfhydryl moieties

To determine whether specific chemical linkages between proteins and haptens could be important in cell-mediated immune recognition of drugs, Penicillin-G (PG) was covalently conjugated to guinea pig albumin through amino (NH2) or sulfhydryl (SH) moieties. Hapten densities ranged from four to one-hundred moles of PG per mole of albumin. Slight differences in cell-mediated immunity to the conjugates were observed for different happen densities or doses of conjugate used for sensitization. Guinea pigs sensitized with PG-albumin conjugates through amino group (PG-NH2) responded to the PG-NH2 conjugate in vivo (delayed skin test) and in vitro (Macrophage Migration Inhibition. MIF) but not to the PG-SH conjugate of albumin. Animals sensitized of PG-SH responded to the PG-SH conjugate, and not to the PG-NH2 conjugate. Penicilloylpolysysine (PPL) and PG were also tested for in vivo and in vitro efficacy to detect the hypersensitivity; PG alone did not result in any increase over baseline values and the inhibition of cellular migration form PG-NH2 sensitized animals challenged with PPL was not statistically significant. In vitro dose response effect for the PG-NH2 conjugate suggest that the MIF assay in not as dose sensitive as lymphocyte transformation, where increase 3H-Thymidine uptake was seen with increase dose of antigen, while migration inhibition remained constant.