title: Immune responses of the bovine fetus and neonate to Escherichia coli: plaque-forming and intestinal immune responses.
abstract: The immune responses of 26 Angus-Hereford fetuses and neonates to Escherichia coli O26:K60:NM were studied after bacterin or saline solution was injected (in utero) into the amniotic fluid. Calves were euthanatized at birth or were orally revaccinated; some were challenge exposed with live organisms. The hemolytic plaque assay was used to determine the presence of cells producing immunoglobulins M, G1, and G2 (IgM, IgG1, and IgG2) in 4 segments of the small intestine, mesenteric lymph nodes, and spleen. The passive hemagglutinin activity of intestinal washings was also determined. Anti-O26 passive hemagglutinin activity in the intestinal washings of principal calves was greater than in that of control calves, but in a given segment of the small intestine, usually this activity was relatively small and less consistent than the plaque-forming response. Greater numbers of plaque-forming cells were observed in the small intestine of 14 of the 15 principal calves when compared with the control calves tested.
mesh_terms: D000818:Animals; D000831:Animals, Newborn / Q000276:immunology*; D000921:Antibody-Producing Cells / Q000276:immunology*; D002417:Cattle / Q000276:immunology*; D004926:Escherichia coli / Q000276:immunology*; D005260:Female; D005333:Fetus / Q000276:immunology*; D006386:Hemagglutination Tests; D006462:Hemolytic Plaque Technique; D007074:Immunoglobulin G / Q000032:analysis; D007075:Immunoglobulin M / Q000032:analysis; D007421:Intestine, Small / Q000276:immunology*; D008198:Lymph Nodes / Q000276:immunology; D011247:Pregnancy; D013154:Spleen / Q000276:immunology
chemical_list: D007074:Immunoglobulin G; D007075:Immunoglobulin M