[Critical involvement of the specific neuroendocrine profile for an adequate T-dependent immune response].
A functional relationship between the neuroendocrine and immune systems has been clearly established. We examined the role of neuroendocrine changes, particularly thyrotropin-releasing hormone (TRH) and prolactin (PRL), during the T cell-dependent immune response. After immunization of rats with sheep red blood cells (SRBC, a T cell-dependent antigen) we observed: a) an increase of hypothalamic TRH mRNA at 4 to 24 h post-immunization (i.e.: SRBC vs saline: 4 h, 2.8x), in contrast to the decrease of TRH mRNA observed following treatment with LPS, a T-independent antigen (LPS vs saline: 4 h, 1.6x); b) an increase in pituitary TRH receptor mRNA and plasma PRL levels but no changes in thyroid-stimulating hormone and growth hormone plasma levels. Intracerebroventricular (icv) injection in conscious freely-moving rats of antisense oligonucleotide complementary to rat TRH mRNA resulted in: a) a significant inhibition of specific antibody production [ELISA 7 days: Ig(M/G): TRH sense vs TRH-antisense: 384 +/- 27 (n = 11) vs 193 +/- 22 (n = 11); p < 0.001]b) an inability to produce the peak in plasma PRL levels in rats immunized with SRBC [(12h post-immunization, TRH-sense vs TRH-antisense: 8.3 +/- 1.4 (n = 6) vs 2.2 +/- 0.5 (n = 6); p < 0.01]; c) a decrease in hypothalamic TRH mRNA (TRH-sense vs TRH-antisense: 12h, 1.7x). These studies demonstrate that the T-cell antigen needs an early activation of TRH and PRL for an adequate immune response, in contrast to the inhibition induced by a T-cell independent antigen.
Laboratorio de Fisiologia y Biología Molecular, Facultad de Ciencias Exacts y Naturales, Universidad de Buenos Aires, Argentina.
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Pérez Castro
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Páez Pereda
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Keller
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Arzt
D000704:Analysis of Variance; D000818:Animals; D000917:Antibody Formation / Q000276:immunology*; D004912:Erythrocytes / Q000276:immunology*; D007107:Immune System / Q000378:metabolism*; D008297:Male; D009490:Neurosecretory Systems / Q000378:metabolism*; D016376:Oligonucleotides, Antisense / Q000276:immunology; D051381:Rats; D017208:Rats, Wistar; D012756:Sheep; D013601:T-Lymphocytes / Q000276:immunology*; D013973:Thyrotropin-Releasing Hormone / Q000097:blood* / Q000378:metabolism
D016376:Oligonucleotides, Antisense; D013973:Thyrotropin-Releasing Hormone