Abstract
To study the antigenicity of BR92021(Vi polysaccharide typhoid vaccine), active systemic ana-phylaxis and passive cutaneous anaphylaxis were tested in guinea pigs. The groups were as follows: group I(low dose, 30 $\mu\textrm{l}$/kg), group II(high dose, 300 $\mu\textrm{l}$/kg), group III(300 $\mu\textrm{l}$/kg plus complete Freund's adjuvant), group IV(positive control, ovalbumin plus complete Freund's adjuvant) and group V(saline-treated control). Male Hartley guinea pigs at 7 weeks of age were sensitized subcutaneously with the test article or saline three times per week for three weeks(j.e., total 9 times). For groups III and IV, animals were sensitized subcutaneously with either the test article or ovalbumin plus complete Freund's adjuvant once per three week for 6 weeks(i.e., total 3 times). Twelve days after the last sensitization, the blood was collected from the sensitized animals for the passive cutaneous anaphylaxis test. In addition, the sensitized animals were subjected to the active systemic anaphylaxis test on fourteen days after the last sensitization by an intravenous challenge with either the test article or ovalbumin. In group I, mild(1/5) or moderate(4/5) symptoms of anaphylactic shock were observed. In group II, no sign(1/5), moderate(3/5) and severe(1/5) symptoms were observed. In group III, four animals of revealed moderate signs and one of 5 showed no signs of anaphylactic shock. In group IV, all 5 animals showed severe signs of shock. In group V, one of 5 revealed moderate and four of 5 showed no signs. The necropsy findings related to the active systemic anaphylaxis were observed in most animals of groups I to V In the passive cutaneous anaphylaxis test, the antiserum was diluted 10- to 5120- fold and was injected intradermally on the clipped back of recipient animals, followed by an intravenous challenge with either the test article or ovalbumin. No animals in groups I, II, III and V showed the positive reaction, whereas all animals in group IV, the positive control, showed the positive reaction at the dilution range of x1280 to x5120. Our results indicate that the test article, BR92021, may have weak antigenic potential in male guinea pigs.
