DEVELOPMENT OF AN ALTERNATIVE METHOD FOR TESTING THE IMMUNOGENICITY OF DIPHTHERIA VACCINES

The immunogenicity of the diphtheria component of 73 commercial vaccin es fr om Jive different manufacturers was rested by the toxin neutrali zation test (TNT) and the enzyme-linked immunosorbent assay (ELISA) de veloped in our laboratory. A comparison of the antibody levels measure d by both assays showed a very good correlation (r=0.95, p < 0.001). T he results suggest that the proposed ELISA is a reliable, simple and e conomical alternative to the TNT in guinea pigs. Also, the ELISA was f ound to measure IgG antibody levels as low as 5.5x10(-5) IU ml(-1). To evaluate the possibility of accelerating the active immunization duri ng the activity test of vaccines an alternative schedule using one sin gle human dose was assayed A very good correlation was observed betwee n the IgG antibody response obtained with this schedule and with the t raditional programme. Therefore, the cost and the time required to per form the activity test may be considerably reduced when both the vapid immunization schedule and the ELISA are used.