EVALUATION OF THE ANTIMENINGOCOCCAL IMMUNOGLOBIN ACTIVITY AGAINST 5 STRAINS OF NEISSERIA-MENINGITIDIS GROUP-B FROM LATIN-AMERICA USING MICEAS MODEL

To know the activity of antimeningococcal immumoglobulin, Balb/c mice of 18-22 g of body weight were challenged with 5 serotype B strains of Neisseria meningitidis (Nm) isolated from patients of different Latin American countries. The specific antimeningococcal Ig was extracted f rom the serum of volunteers previously vaccinated with the antimeningo coccal BC vaccine VA-MENGOC-BC(R) (Finlay Institute, Havana, Cuba). Th e Ig was intraperitoneally (IP) administered in a unique dose of 10 mg /mouse. The strains A, B, C, CH and D were inoculated IP in the follow ing charges: strain A, 20 LD50; B, 25 LD50; C, 44.5 LD50; CH, 36 LD50, and D, 200, 20 and 2 LD50. For each strain, a control group received living bacteria and virulent stimulating factor (VSP). The Ig was inje cted 30 min before or 30 min after the challenge dose had been given, except for strain D, which only received the Ig 30 min after the chall enge. As VSF, 0.5 mg of iron in the form of iron dextran was used. The experiment was analyzed considering the survival time after the chall enge for each strain compared to the corresponding control group (C). When the Tg was used 30 min before the challenge, the protection perio d for the A strain was (C:18.1 h) more than 72 h (P<0.001) and 100% su rvival; for the B strain, (C:29.5 h) 42 h (P<0.05) and almost 20% surv ival; for the C strain (C:16.5 h) 35 h (P<0.01) with a 40% survival, a nd the CH strain (C:18.1 h) 26.5 h (P<0.02), with a 20% survival. When the Pg was injected 30 min after the challenge, the average survival time and the survival for the A strain was 28 h (P<0.05) with 62.5%; f or the B strain it was 42 h (P<0.005) and 0.0%; for the C strain 27.3 h (P<0.05) and 30%; for the CH strain 25.8 h (P<0.05) and 0.0%, and fo r the D strain 19.1 h, 26 h, and more than 72 h with a 0.0%, 60% and 1 00%, depending on the challenging dose. In general, the specific Ig us ed showed a protective effect in mice against the different Latin Amer ican strains tested. Additionally, the experimental model proved to be useful for the study of the antimeningococcal human Ig.