Passive oral immunization with bovine immunoglobulins: enterpathogenic Escherichia coli from infants and bovine anti-E. coli lactoserum assayed in the rabbit ileal loop model.

The effect of immune bovine lactoserum (BLS) antipolyvalent enteropathogenic Escherichia coli on bacterial growth, viability and bacteria-induced fluid accumulation was examined in rabbit ileal loops. Human enteropathogenic E. coli strains 0125:K70 (B15), 0111:K58 (B4) and 055:K59 (B5) (1-3 X 10(9) per inoculum) induced secretion of 4-6 ml fluid per 10 cm loop. This effect was inhibited effectively by BLS (corresponding to 50 mg IgG 1 per loop) while the viability of bacteria counts decreased 2-25 fold compared with bovine serum albumin. E. coli 026:K60 (B6), 0126:K71 (B16) and 0127:K63 (B8) caused moderate secretion (2-3 ml/10 cm loop) that was significantly neutralized by BLS. E. coli 086:K61 (B7) and 0128:K67 (B12) did not give positive loops. The fluid secretion was shown to be dose dependent for E. coli 0125:K70 (B15) over the range from 2.5 X 10(9) to 8 X 10(7) bacteria/loop. The titration of the effect of BLS on fluid secretion caused by the same strain revealed a dose dependent decrease. The best inhibition was obtained with 100 mg BLS/loop, the highest dose tested.