Effect of cationization on anti-hapten antibody responses in sheep and mice.

The effect on anti-hapten immune responses of altering the isoelectric point of hapten-carrier conjugates by cationization was examined in sheep and mice. No adjuvants were employed in these studies. In sheep the cationization of ovalbumin-dinitrophenyl (OVA-DNP) resulted in an enhanced primary anti-dinitrophenyl (DNP) response. The secondary anti-DNP responses were not consistently greater for animals primed with cationized (CAT) OVA-DNP than in animals primed with OVA-DNP. Similar results were obtained with mice immunized with bovine serum albumin (BSA)-DNP or CAT BSA-DNP. Mice and sheep primed with OVA-DNP failed to mount an anamnestic response following secondary immunization with CAT OVA-DNP. Failure of a cationized hapten-carrier to stimulate a secondary anti-DNP response following priming with uncationized hapten-carrier was also observed in mice using BSA-DNP as the model antigen.