Table 1.

ELISA reactivity of antisera raised against recombinant Opc protein preparationsa

FormulationReciprocal geometric mean ELISA titer (10−3) measured against:
Homologous recombinant Opc proteinOMs from strain:
MC58 Opc++MC139 Opc++MC139 Opc+H44/76 Opc+MC114 Opc
Opc+Al(OH)3 3,99076944<1<1<1
Opc-liposomes3441027<1<1<1
Opc+MPLA-liposomes1,83793291<131
Opc-liposomes+MPLA-liposomes7787864<141
Opc-Zwit6501078<1<1<1
Opc+MPLA-Zwit3,02649287<12<1
  • a Mice were immunized with recombinant Opc protein in the preparations described in Materials and Methods. Pre- and postimmunization sera were tested in ELISA against homologous protein and against OMs from the homologous and heterologous strains. Strains MC58 and H44/76 expressed the homologous Opc protein, strain MC139 expressed a heterologous protein; the levels of expression were high (Opc++), low (Opc+), and none (Opc). Preimmune sera and antisera raised against control liposomes with and without MPLA showed no reactivity against antigens in the ELISA (<1).