An improved immunization procedure to obtain Botulinum antitoxin Type A

DE ROODT, ADOLFO; D´ANDREA, C.; DOLAB, JORGE; ALBANO, D.; KERSCHEN, J.; VIDAL, JUAN CARLOS; DOKMETJIAN, CRISTIAN; LITWIN, S.; FUNES, R; HEKER, J.; DINAPOLI, HERNÁN; VARNI, L.; SEGRE, LILIANA

Isla Margarita

Congreso; VI Pan American Congress on Toxinology (IST).; 1998

International Society on Toxinology

Formaldehyde treated and purified botulinum A toxoid (TXD) from C. botulinum(strain ATCC 3502) was treated with 2-mercaptoethanol (∼ 650 mM) at pH 7.0for 6 hr and adjusted to pH 4.8. Compared to the TXD sample, the ?reduced?TXD exhibited a significantly different elution profile by gel-filtration in aSuperdex 200 HR column. The TXD and ?reduced? TXD were injected indifferent sites, in order to produce antitoxic serum in rabbits and horses. NewZealand rabbits were immunized with 7.5 mg each of TXD and ?reduced? TXDemulsified in FCA on day 1; emulsified in FIA on day 15; and adsorbed onaluminium hydroxyde on days 45 and 55. On day 60, the serum exhibited highimmunochemical reactivity with TXD (>1:10000 by ELISA) and had aneutralizing capacity of 100 antitoxic units (ATU) /ml. Cross bred horses received15 mg each of TXD and ?reduced? TXD emulsified in FCA on day 1;emulsified in FIA on day 10, and adsorbed on aluminium hydroxyde on day 30.On day 45, the serum exhibited high reactivity with TXD (>1:7500 by ELISA)and a neutralizing capacity of 500 ATU/ml when tested on CF1 mice. On days 75-90, the animals received a boost of 10 mg each of TXD and ?reduced? TXD forrabbits or 15 mg each of TXD and ?reduced?TXD for horses. The sera obtainedon days 85-100 exhibited a higher immunochemical reaction and neutralizingcapacity ( horse serum > 500 ATU /ml). Compared to the immunization plansrecommended by the P.A. H.O. used in Argentina, this procedure reduces by 4-fold the time required to obtain the antitoxin from horses, employing about 90-fold less purified TXD.