Endocrinology Summers

Hormones Endocrine Glands Receptors Homeostasis 2nd Messengers

Nuclear Receptors Genetic Regulation Hormone Synthesis Receptor Regulation Hypothalamo-Hypophysial Communication

Tropic Hormones Neurohypophysial Nonapeptides Thyroid Axis Steroids Adrenal Axis

Adrenal Medulla Osmotic-Pressure Balance Reproductive Endocrinology Prolactin Somatic Axis

Growth Factors Immune Factors Ca++, PO4 Homeostasis Pancreatic Hormones GI Hormones

Guts 'n Brains Brain Hormones Neurosteroids Neuropeptides Endocrine Evolution

Figures for Endocrionology text:Vertebrate Endocrinology5th Edition - David O. Norris: no Reading pages for this lecture acronyms    end

XXIV. Hormones of the Immune System  	video	

	A. Immune reactions are produced by a cooperative relationship
	    between immune tissues and cells


		1. hormonal communication necessitates secretion
		   from glands and lymphocytes


			a. glandular hormones:


				i. thymosins, thymopoietin, thymulin, chemotactic hormones 
				

					1) all from the thymus


			b. cellular (lymphocytic) hormones = Cytokines + Interleukins


				i. Lymphokines = ACTH, BF (blastogenic factor), CSF (colony stimulating factor),
				   GM-CSF (granulocyte macrophage - CSF), g-Ifn (g interferon),
				    IL3 (interleukin 3), MAF (macrophage arming factor),
					MIF (migration inhibitory factor), OAF (osteoclast activating factor)

 
					1) produced by T lymphocytes


				ii. macrophage hormones: TNFa (tumor necrosis factor), TNFb


				iii. Interleukins = IL1, IL2, IL4


					1) related hormones = BCGF (B cell growth factor),
					    BCDF (differentiation factor),
						TRF (T cell replacement factor; may = BCDF)


	B. Hormones of the Thymus


		1. stimulate T cell differentiation


			a. differentiation first seen in the thymus
			   then in the periphery


				i. induce the appearance of differentiation antigens
				   and T cell function


			b. chemotactic hormones attract precursor cells into the thymus


		2. Thymulin (9 aa = Serum Thymus factor), Thymopoietin (49 aa),
		    Thymic Humoral Factor (31 aa)


			a. produced by epithelium of the thymus


			b. bind to high affinity receptors on T cells and precursors


				i. thymopoietin induces differentiation of bone marrow cells
				   into T lymphocytes


				ii. thymulin is mitogenic: enhancing generation of
				    cytotoxic and supressor T cells 


			c. negative feedback on thymulin secretion is [thymulin]


	C. Hormones made by T cells					


		1. Lymphokines are glycoproteins


		2. receptors on different cell types they activate


		3.  Specific recognition of the antigen necessary for production


			a. lymphokines are not specific to an antigen


			b. target tissue may be specific


				i. macrophages: MIF, MAF
				
				
					1) macrophages also make hormones: TNFa
					    (Lymphotoxin B, cachexin or cachectin)

						a) also released by lymphocytes and endothelium
						
							i) other damaged tissue
							
							ii) stimulated by IL1

						b) trimeric protein encoded within the major
						    histocompatibility complex
							
							i) structure shared with viral coat proteins
							    - originated from a common ancestor?

						c) bind TNFR55 & TNFR75

						d) inflammatory
						
						e) amplify release of ILs, and CRH/HPA
						
						f) increases vascular permeability
						
							i) via c & d recuits more macrophages
							
							ii) blood clotting

						g) growth simulatory & inhibitory
						
						h) injury repair - stimulates fibroblast growth
						
						i) kills tumors, bacteria, fungus, viruses, parasites

						j) helps regulate circadian rhythms


				ii. stem cells: CSFs, IL3,


				iii. bone cells: OAF


			c. target tissue may not be specific: g-Ifn


		4. Interleukins, other than IL1, are also produced by T cells


	D. Interleukins


		1. intercellular communication


			a. activation, mitosis, development


		2. IL1  (also LAF = lymphocyte activation factor)


			a. produced by macrophages and monocytes (give rise to macrophages)


			b. stimulated by antigen or mitogen


			c. activates B cells and induces production of IL2 by T cells


		3. IL2  (TCGF = T cells growth factor)


			a. produced by T cells and acts on T cells
			   via high affinity receptors


				i. promoting growth


					1) enhances effects of other lymphokines


			b. acts on B cells


				i. less effective


		4. BCGF, BCDF, TRF, IL4 have effects specifically on B cells


	E. POMC


		1. Lymphocytes produce POMC


			a. release ACTH


			b. have MC2 or MC3 receptors


				i. ACTH and glucocorticoids inhibit immune function