Figure 5

Protection of rats from a lethal toxin challenge five minutesafter administration of antibody Male Fisher 344 rats with jugular vein catheters weighing between 200–250 g were administered human anti-anthrax PA IgG monoclonal antibodies AVP-21D9, AVP-22G12, AVP-1C6, or the control human IgG in 0.2 ml PBS 0.1% BSA pH 7.4, 5 minutes later lethal toxin (PA 20 μg + LF 4 μg/200 g rat in 0.2 ml PBS 0.1% BSA pH 7.4) was administered. The dose of antibody was 0.25 and 0.12 nmols/rat corresponding to 1× and 0.5× molar equivalent to the lethal toxin. Five animals were used in each test group and four animals in each control. Test and control experiments were carried out at the same time using the same batch of reconstituted PA and LF toxins. Animals were monitored for discomfort and time of death, as assessed on the basis of cessation of breathing and heartbeat. Rats were maintained under anaesthesia for 5 hr post exposure to lethal toxin or until death to minimize discomfort.