Colonization required for newborn piglets to make serum antibodies.

2003 FEB 12 - (NewsRx.com & NewsRx.net) -- Only those newborn piglets that colonized with a benign or enterohemorrhagic strain of Escherichia coli produced antigen-antibodies, according to researchers in the United States.

"Cesarean-derived piglets were reared for 5 weeks under germfree conditions or monoassociated with a benign E. coli (G58-1) or a enterohemorrhagic strain (933D) derived from O157:H7, and immunized i.p. with the T-dependent (TD) antigens fluorescein-labeled (FL) keyhole limpet hemocyanin or trinitrophenylated (TNP) keyhole limpet hemocyanin and the type 2 T-independent antigens TNP-Ficoll or FL-Ficoll," reported John E. Butler and colleagues at the University of Iowa in Iowa City. "Only colonized piglets showed an increase in serum IgG, IgA, and IgM and had serum Abs to FL, TNP, and colonizing bacteria. While serum antibodies to FL or TNP appeared following colonization alone, secondary responses were restricted to piglets immunized using TD carriers.

The investigators stated, "While animals colonized with 933D had significantly higher total serum IgG and IgM levels and specific IgG Abs than those colonized with G58-1, no differences were seen in serum IgA levels, B cell diversification in the ileal Peyer's patches, and specific activity (ELISA activity per micrograms of Ig) of pre-boost serum IgG and IgM anti-TNP and anti-FL antibodies. Serum IgA antibodies to TNP, FL, or bacteria were not detected. Antigen-driven responses, as measured by an increase in specific ...