The relationship between the hypothalamic-pituitary adrenal axis and oral-induced immunosuppression.
The effects of hypophysectomy on the immune response in mice orally immunized with sheep red blood cells (SRBC) was investigated. Hypophysectomized and sham-operated animals display elevated serum levels of SRBC-specific IgG. In addition, splenic lymphocytes obtained from hypophysectomized mice (i) exhibit an enhanced blastogenic response to SRBC, (ii) present with a lower frequency of T (thy 1.2+) cells and produce more total IgG polyclonal antibody in culture in comparison to splenic lymphocytes obtained from non-operated (control) mice. Peyer's patch (PP) and mesenteric lymph node (MLN) lymphocytes from hypophysectomized animals secreted elevated levels of total IgG compared to saline-treated controls. The culture supernates of splenic lymphocytes obtained from hypophysectomized, sham-operated, and control animals contain interleukin-2 suppressive factors as determined using the CTLL-2 cell line. The suppressive effect mediated by the lymphocyte culture supernates is less apparent on interleukin-4-mediated CTLL-2 proliferation. The culture supernates from PP lymphocytes obtained from hypophysectomized mice contain potent interleukin-2 suppressive factors while PP lymphocyte culture supernates from sham-operated and control mice displayed no suppressive activity. Likewise, culture supernates from MLN lymphocytes of hypophysectomized, sham-operated, and control mice possessed no suppressive factors for interleukin-2- or interleukin-4-mediated CTLL-2 proliferation. Taken together, the identification of suppressive factors in the lymphocyte culture supernates along with the enhanced blastogenic response and serum anti-SRBC IgG levels in hypophysectomized mice suggests neuroendocrine pathways regulate oral-induced tolerance.
Department of Microbiology, Immunology, and Parasitology, Louisiana State University Medical Center, New Orleans 70112.
D J
DJ
Carr
T W
TW
Woolley
B L
BL
Clarke
D000818:Animals; D046508:Culture Techniques; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D007016:Hypophysectomy; D007030:Hypothalamo-Hypophyseal System / Q000276:immunology*; D007114:Immunization; D007074:Immunoglobulin G; D007165:Immunosuppression Therapy; D007376:Interleukin-2 / Q000276:immunology; D015847:Interleukin-4 / Q000276:immunology; D008198:Lymph Nodes / Q000276:immunology; D008214:Lymphocytes / Q000276:immunology; D051379:Mice; D015213:Neuroimmunomodulation; D010913:Pituitary-Adrenal System / Q000276:immunology*; D013154:Spleen / Q000276:immunology
D007074:Immunoglobulin G; D007376:Interleukin-2; D015847:Interleukin-4