Effects of antigen and antigen concentration on serum antibody titres in chickens primed per bursam.
A novel method for intrabursal immunization was applied to study the priming effect in 2-day-old and 4-week-old chickens. This immunization method separates the bursa of Fabricius totally from the rest of the gut-associated lymphoid tissue (GALT), and closely mimics the natural way antigens come in contact with the bursal epithelium. Sheep red blood cells (SRBC) and Brucella abortus organisms in 4 different concentrations were used as antigens. In 4-week-old birds, a suppressive effect of per bursam priming on the secondary anti-SRBC titres was recorded, an observation not reported earlier. Priming had no effect on the secondary anti-SRBC titres in 2-day-old chickens. In both age groups, a positive priming effect on anti-Brucella titres was observed. Antigen concentrations too low to induce primary immune responses in serum were still capable of causing the priming effect. A certain minimum concentration, however, was required also for the priming effect to occur. The observed suppressive effect of priming on the secondary anti-SRBC titres suggests that bursa exerts inhibitory immuno-regulatory functions when handling certain antigens. Important factors are the age of the chickens and the antigen concentration used, which influence both the primary and the secondary immune responses.
Naukkarinen
A
A
Department of Clinical Pathology, University Central Hospital, Kuopio, Finland.
Hippeläinen
M
M
D000367:Age Factors; D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis; D000917:Antibody Formation; D000942:Antigens, Bacterial / Q000008:administration & dosage; D002003:Brucella abortus / Q000276:immunology; D002060:Bursa of Fabricius / Q000276:immunology*; D002645:Chickens / Q000276:immunology*; D004306:Dose-Response Relationship, Immunologic; D004912:Erythrocytes / Q000276:immunology; D007156:Immunologic Memory; D007422:Intestines / Q000276:immunology; D008297:Male
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial