Comparison of the immune response to Ars-BGG in germfree or conventional piglets.

Neonatal germfree (GF) colostrum-deprived and conventional (CV) colostrum-fed piglets were immunized IP with p-azo-phenyl-arsonate-bovine gamma globulin (Ars-BGG) in Freund's adjuvant to study the development of the immune response in the absence or presence of maternal antibodies and environmental antigens. Overall, the immune response varied greatly within each group but did not differ in GF from CV piglets statistically. Affinity immunoblot analysis suggested that anti-Ars antibody was more restricted in GF than CV piglets and clonotype shifts occurred more in GF than CV piglets after each antigenic stimulation. In contrast, the clonotype pattern of the anti-BGG antibody was similarly heterogeneous in the two groups. Based on the affinity immunoblot data the antibodies generated to the Ars-haptenic group in CV piglets are more heterogeneous than GF piglets and suggest that clonotype generation is influenced by maternal antibodies and environmental antigens.

Intestinal absorption of immunologically intact macromolecules in germfree colostrum-deprived piglets maintained on total parenteral nutrition.

We have compared the neonatal absorption of anti-bovine gamma-globulin (BGG) antibody supplied in colostrum or saline in three groups of piglets born and maintained under different environmental conditions to determine the effect of these conditions on the cessation of intestinal absorption of macromolecules (anti-BGG antibody), termed "closure." An enzyme-linked immunosorbent assay was used to estimate the concentration of anti-BGG antibody in sera from each group of piglets. Three stages of macromolecular absorption through the piglet's intestine could be detected. The first stage is a nonselective massive absorption of macromolecules (in milligram levels) that lasts up to 3 days in germfree (GF) colostrum-deprived or conventional colostrum-fed piglets but up to 5 days in GF piglets maintained on total parenteral nutrition. In this stage, absorption was significantly (r = .05) higher in piglets fed anti-BGG serum with colostrum than in piglets fed anti-BGG serum without colostrum on GF day 0 (31.28% vs 15.59%) and GF-total parenteral nutrition day 3 (3.08% vs 0.11%). Thus, whenever there was the ability to absorb a massive amount of macromolecules, the sow colostrum had an enhancing affect. Although there was a minor effect of environmental or orally received stimuli in delaying closure, absorption of macromolecules decreased in all piglets maintained either parenterally or enterally after day 3. Thus, intestinal closure to massive absorption of macromolecules in piglets is primarily time (age)-dependent. The second stage is a selective absorption of immunoglobulins in much smaller quantities (microgram levels), inasmuch as absorption of 0.02% to 0.1% was determined in all 5-day-old piglets.(ABSTRACT TRUNCATED AT 250 WORDS)

Synchronous regulation of VH and CH allotypes among Ig molecules in multi-heterozygous rabbits suppressed with anti-VH allotype antibody: emergence of IgA from suppression prior to IgG and IgM.

Heterozygous rabbits of genotype a1n81f73g74/a2n82f71g75 were suppressed at birth for the VH region a1 allotype. At 8 weeks of age, quantitative analysis of serum IgG, IgM, and IgA molecules showed that the VHa1 specificity was effectively suppressed in the three classes of Ig and that the suppression was extended to the CH region n81 specificity on mu-chains as well as to the CH region f73 and g74 specificities on alphaf and alphag chains. At 26 weeks of age, analysis of serum IgG and IgM molecules showed that a1 was still suppressed to approximately the same extent in both Ig classes and the suppression was still extended to the CH region n81 specificity. However, at 26 weeks, the percentage of molecules with a1 specificity had doubled among serum and colostral IgA molecules and this increase was extended to the CH region f73 and g74 specificities. Thus, the suppressed allotypes reappeared first among IgA molecules. Our data are consistent with a regulatory mechanism which controls and synchronizes the expression of the VHa and the CH allotypes expressed on the same heavy chain. The order of the re-expression of the suppressed allotypes with respect to Ig class may allow further definition of selective regulatory mechanisms for the synthesis of Ig classes.