Study of the effect of antibodies in the intestinal tract of germ-free baby pigs

Abstract

The effect of antibodies in the intestinal tract was studied in germ-free baby pigs whoso intestinal barrier was closed to macromolecules by the peroral administration of modified cow's milk for the first 72 hours after birth. They were then all contaminated with the pathogenic strain Escherichia cell 055 in amounts of 10' bacterial cells pcr animal. The controls, which were not given any antibodies, all died within 24 hours. All the experimental animals given 12.5--50 ml immune colostrum or serum survived, while of those given 50 ml normal serum or colostrum containing natural antibodies reacting with the Escherichia cell test strain, 50~ survived. ~'o circulating antibodies were found in the serum of the experimental animals after the administration of ~rum or colostrum. The antibodies present in colostrum thus appear to protect the newborn organism directly in the intestinal tract, which is the first site of bacterial invasion, as well as after infiltration into the blood stream.

Mucosal Immunoglobulins

“…Furthermore, glycans with characteristically high content on the a and m chains and on SC interfere with microbial adherence to mucosal surfaces, irrespective of their specific antibody activity(see below). The essential protective role of mucosal antibodies within the intestinal lumen was convincingly demonstrated in a unique model of colostrum-deprived newborn piglets, where survival is fully dependent on the ingestion of antibodies irrespective of their isotype (120). More recently, numerous experiments performed in mice either carrying 'piggy-back' hybridoma tumors that secrete monoclonal antibodies specific for various microbial antigens, or passively administered monoclonal antibodies of such specificity, clearly demonstrated the protective role when such animals were infected with corresponding pathogens by various mucosal routes (21).…”

Mechanisms of Neonatal Mucosal Antibody Protection

“…Milk contains secretory Ig (S-Ig)A and S-IgM Abs that bind enteric pathogens or their toxins, which are partly induced in the maternal intestinal lymphoid follicles. Milk IgA and IgM are not absorbed significantly in any species and act locally in the intestinal lumen (11). Whether these secretory Abs need to undergo germinal center selection and somatic hypermutation for a neutralizing function against commensals or pathogens, or whether natural germline specificities suffice to provide a primitive exclusion mechanism has not been shown.…”

Historical Aspects of Mucosal Immunology

“…The essential protective role of intestinal antibodies in survival was demonstrated 35 years ago in a unique model of GF, colostrum-deprived newborn piglets (Rejnek et al, 1968). Because of the absent transplacental transport of antibodies, when deprived of milk, these animals die of septicemia with environmental bacteria, as described earlier.…”