The contrasting properties of 2 xenogenic erythrocyte-reactive natural antibodies in commercial ducks

Abstract

Sera obtained from commercial drakes on days 14 and 38 of age were tested by microtiter for the capacity to agglutinate and lyse rabbit (Rb) and human (HuO) erythrocytes. Three agglutination types, differing by strength, were recognized: HA1 (strong), HA2 (weak), and HA45 (very weak).Two degrees of lysis: L100 (complete) and L50 (partial), measured complement activity. Day 14 sera agglutinated Rb (average log2 titers: HA1 = 1.5, HA2 = 4.1) and lysed Rb (average log2 titers: L100 = 2, L50 = 2.5) but only 8/115 (˜9%) agglutinated HuO (HA45 = 0.4) while most (>80%) lysed HuO (average log2 titers: L100 = 1.3, L50 = 1.8). Both Rb and HuO agglutination and lysis titers were higher by d 38. At that age, all ducks lysed HuO and 50% of ducks acquired a capacity to agglutinate these cells with more strength. However, the quality of HuO agglutination could not be differentiated into HA1 or HA2 types. Average d 38 log2 titers of all measures were Rb: HA1 = 4, HA2 = 8.4, L100 = 3, and L50 = 4; and HuO: HA = 2.8, L100 = 3.9, and L50 = 1.2. The quality of the Rb agglutination suggested the participation of both IgM and standard-sized IgY antibodies. Lysis of Rb may occur by both classic and alternate complement pathways. The HuO lysis appears to depend primarily on the alternate complement pathway. It is suggested that multiple measurement systems such as these offer a practical way of obtaining information on immunity in experiments where the chief interest lies elsewhere.