Germfree (GF) animals are widely used for discrimination of natural mechanisms (genetically determined) from adaptive mechanisms of immunity induced by external antigens. GF rats fed at least for first 5 days after birth with artificial diet LNa, deficient in unsaturated fatty acids, were in contrast to those fed with K 50 diet deeply suppressed in humoral and cellular immune reactivities during their life. GF piglets, deprived from maternal colostrum (CF) as a source of passively transferred maternal antibody, immunized with preformed Ag/Ab complexes (HSA anti HSA) responded according to the composition of complexes (Ab excess, equivalence, Ag excess) by low or high dose tolerance or by secondary response. Similar pictures of response were obtained in groups of presensitized GF-CF piglets by immunization with different doses of antigen. It is concluded that 3 different types of response are the result of Ag/Ab complexes acting or formed on the lymphocyte membrane and exerting stimulatory or down-regulatory signals.
- MeSH
- dieta MeSH
- fyziologie výživy zvířat * MeSH
- gnotobiologické modely * MeSH
- imunita * MeSH
- imunologická tolerance MeSH
- inbrední kmeny potkanů MeSH
- kalorimetrie MeSH
- krysa rodu Rattus MeSH
- pasivní imunizace MeSH
- prasata MeSH
- výzkumný projekt MeSH
- zvířata MeSH
- Check Tag
- krysa rodu Rattus MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
The ability of some pathogenic strains of E. coli to adhere to the intestinal epithelium significantly enhances their effectivity. This adhesion of particular pigs' strains is mediated by specific pili possessing the K 88 antigen found on the outer membrane of the bacterial cell. In in vitro experiments with isolated piglets' enterocytes, a considerable adherence of the E. coli K 88+ strain was found when compared with the same bacterial strain but lacking this plasmid-directed antigen. Comparable results were obtained in in vivo experiments with ligated intestinal loops as well as with monoassociated piglets. Furthermore, the adherence ability is most pronounced at the early postnatal period and is negligible in adult pigs.
