EFFECTS OF EARLY BURSECTOMY AND BURSIN ADMINISTRATION ON ADRENOCORTICOTROPIC AND IMMUNE RESPONSES TO REPEATED IMMUNIZATION J.D. Bayl t 1, M. Guellati 1, F. Boudard 2, F. Ramade !, hi. Bastide 1. lEndocrine Nenrobiology Unit, UP, A CNRS 1197, University of Montpeilier I~ 2Immunology Research Unit, Facult~ of Pharmacy, University of Montpellier 1;34060 Montpellier, France. Plasma ACTH and corticosterone (C) levels ~ ~ntibodies to porcine thyroglolmlin (TG) were measured before and after repeated injections at 1-week intervals of TG to either intact (/) or bursectomized (BX) chicken embryos. BX embryos received either saline (BXS) or bursin (BXB) at 6 and 9 days of incubation. Antibodies to TG were initially near zero in all 3 groups and remained at the very low background levels in BXS birds in spite of repeated immunizations, where~ts v~y high secondary immune responses oecuned in group I. In eve administrafiou of bursin {BXB) led to partial or complete restoration of t.~e antibody response to 7G according t~ the dose injected (100 fg was more. effective than 100 pg and 100 pg more *J't~,~ 1001~g). Initial resting hormone levels were similarly low in groups I, BXS and BXB. Controls exhibited high levels (x3) of ACTH and C after the 2 nd injection of TG. This response did not appear in BXS animals and was not restored in BXB chickens treated with 100 pg of bursin. However, the horraonal stimulation was almcet normal in BXB birds given 100 pg or 100 fg of bu~in in eve. These results support the hypothesis that the bursa exerts an early influence on the functional maturation of the adrenocorticotropic axis and on the production of specific antibodies, at least partly, through the xeleas~ of the h~ipeptide bursin by the embryonic bmsal epithelium.

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EXPRESSION IN HUMAN LYMPHOCYTES OF A PEPTIDE AND mRNA RELA ..TED TO GROWTH HORMONE - RELEASING HORMONE Richard Knight, Anastassis Stephanou* and Stafford L; Lightman* "

Department of Cystic Fibrc~_i.q~ NI-ILI, Brompton Hospital, Mvnresa Road, London, SW3 6LR, and * Department of Nenroendocrinology, Chafing Cross & Wesmfinist~ Medical School, Charing Cr~s Hospital, Fulham Palac~ Road, London, W6 8RF, U.K. Recent work has shown that lymphocytes elaborate mRNA's and peptides similar to the anterior pituitary hormones. We have now detected an mRNA and a peptide related to Growth Hor~one - Releasing Hormone (GI-LRI-I) in h u n ~ lymphocytes. Two transcript species, one of 10 Kb and another of 0.75 Kb (the latter identical t~, the one found in normal pituitary) were found by Northern analysis, although the expression of the 10 Kb species varied within experiments. The intensity of hybridization was modulated by lymphocyte activation in a Mixed Lympboc~ Culture (MLC). Resting lymphocytes contained a peptide reactive with anti - GHRH antisera, wl'dch was r e l ~ into the culture medium following activation. Although titration curves of the lympl',ocyte GHRH peptide were parall31 with standard pepfide GHRtt 144 in the radioimmun ~may, lymphocyte GHRH eluted in later fractions on reverse phase HPLC and behave, d on S.~l~,adex gel filtration with an apparent molecular weight of 50 Kd. Bot.h lyrnpbocyte- derived peptide and GHRH 144 induced transcription of Growth Hormone (GH) m ~ A in dispersed pituitary cells and in lyml:hocytes. Since other studies have shown that GHRH 144 has imrnunologica; e~'ec~, this d~a suggests bo~ that hypothalamic - like ~ne. pfide~ elaborated by lyraphocytes may function as lymphokines and that thvy may have a similar functional relafionshio to their pituitary equivalents in !ymphocytes as in the hypothalamic - pituitary axis.