Passive immunotherapy in neonatal calves—I. Safety and potency of a J5 Escherichia coli hyperimmune plasma in neonatal calves

Abstract

A pair of studies designed to assess the clinical safety and potency of hyperimmune plasma administration was undertaken in neonatal calves. Bovine plasma from Holstein heifers hyperimmunized with a mutant Escherichia coli O111:B4 (J5) vaccine which had a geometric mean (GM) immunoglobulin G (IgG) ELISA titer of 3.5 × 10 4, was administered subcutaneously to ≤2-day-old calves. In the first (study A) of two prospective trials, hyperimmune plasma was administered in two doses to colostrum-deprived (CD) ( n=7) and colostrum-fed (CF) ( n=16) neonatal dairy calves. Data were collected immediately before (0 h) and 6, 24, 48, 72, 96, 120 and 288 h after the first plasma administration. Total serum protein and serum IgG concentration elevated in both groups with a significant ( p<0.01) rise of E. coli J5-specific IgG from the corresponding baseline by 6 h post-plasma administration. In the second (study B) trial, calves ( N=75) allocated into three protocol groups received two doses of either the hyperimmune (TT) J5 plasma ( n=30) or the control (CT) plasma ( n=30), and the third group (NT) received no plasma ( n=15). Data were collected up to 96 h post-plasma administration. Serum IgG and J5 specific ELISA antibody titer increased significantly ( p<0.01) in TT calves compared to the other group calves. The endotoxin contents of the administered plasma were ≤1 EU ml −1 by limulus amebocyte lysate (LAL) method and the collected physiological and hematological data values were similar in all groups in both trials. In addition, no immediate adverse reaction or death was observed in any phase of the plasma administration. The E. coli J5 hyperimmune bovine plasma, as prepared and administered to neonatal calves in the current trials, proved to be a safe and potent biomedical fluid.