猪脾脏结构和功能及其免疫关键基因研究进展

脾脏作为猪最大的次级淋巴器官,含有多种免疫活性细胞和免疫因子,是先天性免疫和适应性免疫重要的应答场所,具有广泛的免疫调控功能;同时可清除衰老、损伤红细胞及过滤病原体,并在造血和储藏血细胞方面具有重要作用。这些功能与脾脏的结构密切相关,其中红髓主要作为血液滤过器,执行造血、储血和清除异物的功能;白髓是免疫的主要区域,含有多种免疫细胞,可执行特异性免疫应答调控功能;而边缘区是连接两个区室的重要桥梁,使所有细胞和抗原都能通过其进入脾脏不同部位。不同的发育和免疫关键基因是实现脾脏功能的根本,发育基因的表达保证了其结构的完整,为脾脏执行各种功能提供空间。免疫关键基因的表达确保了免疫反应进行,其中不同模式识别受体基因的表达保证了先天性免疫的吞噬和识别应答,而各种免疫细胞分泌的多种细胞因子和免疫活性物质是获得性免疫反应的基础,实现机体清除和监控抗原的生理过程。随着脾脏研究的深入,对其各种免疫细胞和免疫功能有了新的认识。作者首先阐述了脾脏组织不同区域的生物学功能;然后结合机体免疫应答机制,论述脾脏先天性和特异性免疫功能以及所需免疫细胞和免疫因子的作用与关联;最后简单介绍了脾脏胚胎期和出生后期的组织发育和免疫相关基因,总结了猪脾脏先天性免疫中重要的模式识别受体及其基因家族,为研究猪脾脏先天性免疫功能提供参考。     

The spleen morphophysiology of fruit bats

Spleen is one of the important lymphoid organs with wide variations of morphological and physiological functions according to species. Morphology and function of the spleen in bats, which are hosts to several viral strains without exhibiting clinical symptoms, remain to be fully elucidated. This study aims to examine the spleen morphology of fruit bats associated with their physiological functions. Spleen histological observations were performed in three fruit bats species: Cynopterus titthaecheilus (n = 9), Rousettus leschenaultii (n = 3) and Pteropus vampyrus (n = 3). The spleens of these fruit bats were surrounded by a thin capsule. Red pulp consisted of splenic cord and wide vascular space filled with blood. Ellipsoids in all three studied species were found numerously and adjacent to one another forming macrophages aggregates. White pulp consisted of periarteriolar lymphoid sheaths (PALS), lymphoid follicles and marginal zone. The lymphoid follicle contained a germinal centre and a tingible body macrophage that might reflect an active immune system. The marginal zone was prominent and well developed. This study reports some differences in spleen structure of fruit bats compared to other bat species previously reported and discusses possible physiological implications of the spleen based on its morphology.     

The in vitro effect of bovine lactoferrin on the activity of organ leukocytes in rainbow trout (Oncorhynchus mykiss), European eel (Anguilla anguilla) and wels catfish (Silurus glanis)

Lactoferrin (LF) is a glycoprotein found in milk, neutrophil granules, secretions and selected organs of mammals. Lactoferrin exhibits antibacterial, antiviral, fungicidal, immunoregulatory and other functions. Although fish are devoid of this protein and its cell receptors, LF effect on the immune mechanisms of fish has been demonstrated. The objective of this study was to investigate the effect of bovine lactoferrin, applied in vitro, on the activity of head kidney and spleen leukocytes in three freshwater fish species: rainbow trout (Oncorhynchus mykiss), European eel (Anguilla anguilla) and wels catfish (Silurus glanis). The obtained results validate LF beneficial effect on the respiratory burst of phagocytes in rainbow trout and wels catfish despite the fact that the potential killing activity against Aeromonas hydrophila was not stimulated in any of the studied species. Bovine lactoferrin enhanced the proliferation of T-lymphocytes in rainbow trout and European eel, as well as of B-lymphocytes in rainbow trout.     

Neurotrophin receptor-like proteins in the bovine (Bos taurus) lymphoid organs, with special reference to thymus and spleen

Increasing evidence suggests that neurotrophins could regulate immune functions acting directly or indirectly on immunocompetent cells. The indirect pathway involves stromal cells of the primary and secondary lymphoid organs. In the present study the occurrence of Trk proteins (TrkA, TrkB and TrkC), regarded as the high-affinity signal-transducing receptors for neurotrophins, was investigated in cow lymphoid organs using immunohistochemistry. The thymus and spleen of both fetal and adult animals, and the palatine tonsils, lymph nodes and Peyer's patches of adult animals, were analysed. Unidentified cells displaying TrkA-like immunoreactivity were found in the fetal thymus, whereas those expressing this protein in the adult gland were identified as epithelial cells. In the spleen, immunoreactive TrkA was observed in cells of the white pulp. TrkB immunoreactivity in both fetal and adult thymus and spleen was localized in monocyte/macrophage cells. As a rule, TrkC was absent from the thymus and the spleen independent of the animal's age. Different types of stromal cells, but never the lymphocytes themselves, displayed TrkA, TrkB, or TrkC immunoreactivity in the other lymphoid organs analysed. As in other vertebrate species, Trk proteins in the lymphoid organs of the cow were localized in the stromal, non-lymphoid cells, thus suggesting that neurotrophins might regulate the immune function acting indirectly on lymphocytes.     

The haemocytology and histology of the haemopoietic organs of South African fresh water fish. I. The haemopoietic organs of Clarias gariepinus and Sarotherodon mossambicus

The haemopoietic organs of the catfish, Clarias gariepinus, and the Mozambique bream, Sarotherodon mossambicus, were studied. In both species the primary haemopoietic organs are the pronephros, the mesonephros and the spleen. The peritoneum and, particularly in catfish, the omentum are of secondary importance in haemopoiesis.     

Extracellular matrix composition of different spleen compartments of fruit bats

The distribution and composition of extracellular matrix (ECM) of the spleen in two species of fruit bats, namely Cynopterus titthaecheilus and Rousettus leschenaultii, were examined by histochemistry and immunohistochemistry. Reticular fibres accompanied by laminin were identified to make up the splenic stromal network. Types I and III collagen were identified in various spleen compartments with varying intensities. Thin and short elastin fibres were scattered in several parts of the spleen. Visualization of the ECM of the spleen can better demonstrate spleen compartmentalization. The alleged vascular space structure in the fruit bats spleen was the sinus structure that was strengthened by the presence of reticular fibres that limit the sinus basement membrane. The present study identified periellipsoidal lymphoid sheath (PELS)-like structure in fruit bats spleen that had never been identified in mammals before. In addition to describing the structure, this study highlighted the variations in ECM composition of the spleen between species that can provide new insight into the phylogenetic study of spleen morphology.     

哺乳动物发情周期黄体的组织学研究进展

黄体是排卵后形成的暂时性的内分泌组织 ,在一个较短的存在期限中经历了一系列的结构变化和分泌阶段 ,对于哺乳动物维持正常的生殖功能具有重要作用。人们对黄体细胞的来源、组成、形态及大小持有不同的观点。近年来 ,人们就黄体细胞的功能和退化、溶解进行了较为深入的研究 ,发现不同动物黄体细胞的功能各有不同 ,黄体退化、溶解与细胞凋亡有密切关系。了解哺乳动物发情周期黄体的组织结构对于控制动物的繁殖具有重要意义。文章对哺乳动物发情周期黄体中不同类型黄体细胞的来源、组成、形态、功能及退化、溶解 ,黄体细胞的分泌方式和超声波在黄体研究中的运用作了概述     

Oral biology and disorders of tusked mammals.

Tusked mammals can be terrestrial or aquatic. Many of these magnificent animals are kept in captivity all over the world. Functions of tusks vary as much as the species in which they occur. Dental anomalies and disorders of tusks and the rest of the dentition in these mammals were discussed, with an emphasis on the elephant. The tusk anatomy, with its large, conically-shaped pulp, makes it an ideal tooth for partial pulpectomy treatment in trauma cases where the pulp is exposed. Surgical techniques for tusks have been developed and were discussed. Oral tumors occur, but are rare.     

Angioarchitecture of collateral arteries of the aortic arch of Antillean manatee (Trichechus manatus manatus Linnaeus, 1758)

The aortic arrangement is an important structure associated with the maintenance of homeostasis. Based on this information, this study was conducted to describe the collateral arteries of the aortic arch of Antillean manatee and define the standard model for the species. Three specimens, an adult male, adult female and a male neonate, all strandings on the coast of the state of Rio Grande do Norte, Brazil, were used. The study was performed in the Laboratory of Morphophysiology of Vertebrates of the Federal University of Rio Grande do Norte, where in situ photographs were taken to demonstrate their topography. Subsequently, their hearts were removed and fixed in 10% formaldehyde and after 72 hr were dissected and analysed, obtaining schematic drawings and photographs of the vascular arrangement. The aortic arch was represented by three collateral arteries identified as the brachiocephalic trunk, left common carotid artery and left subclavian artery. This arrangement was similar to that found for other sirenians, and yet, for other mammals like hooded seal, murine, margarita island capuchin, black-handed tamarin, Mongolian gerbil and human. The morphological similarity presented in this study with different species of mammals, including humans, may contribute valuable information from an evolutionary point of view.     

Leishmaniasis in Canis familiaris – a Report About Microvascular and Cellular Architecture of the Infected Spleen

Leishmaniases are a globally widespread group of parasitic diseases from the group of anthropozoonoses. They are caused by an intracellular protozoan parasite that causes a wide spectrum of diseases in humans and dogs worldwide. In fact, the dog is considered one of the most important reservoir. The spleen is one of the several haematopoietic and immunocompetent organs involved. As this organ is a blood filter, the authors looked for the expression of this infection over the microvascular environment and modifications of the spleen cell population related to immunological responses to this parasitic condition.
Tools:  Scanning electronic microscopy over intact tissue and corrosion casts, transmission electronic microscopy, histology and immunohistochemistry (MAC 387 and CD3).
Results:  Our results show three important modifications concerning the microvascular architecture of the spleen when compared to the normal pattern. A striking scarcity of the sinusoidal system sheath that surrounds the central arteries of the white pulp, a huge development of pulp venules and veins, differentiation of typical features of high endothelial venular cells.
Remarks:  According to our results it seems that independent of the virulence of the parasite involved and the kind of immunity prevalent in a particular host, the spleen develops blood dynamic conditions that allows a sluggish blood flow so that cells involved in immunological processes can proliferate and differentiate and it also contributes to the trapping of lymphocytes to the area through the differentiation of typical characteristics of HEV endothelial cells.     

Pathological, ultrastructural, and immunohistochemical changes caused by Lelystad virus in experimentally induced infections of mystery swine disease (synonym: porcine epidemic abortion and respiratory syndrome (PEARS))

The pathogenicity and pathogenesis of Lelystad virus was studied in six 6-day-old SPF piglets. A third passage of the agent was propagated on porcine alveolar macrophages and intranasally inoculated into pigs. Pigs were killed at hours 24, 48, 60, and 72, and on days 6 and 8 after inoculation. From day 2 on pigs developed diffuse interstitial pneumonia with focal areas of catarrhal pneumonia, and from this day on splenic red pulp macrophages were enlarged and vacuolated. Lelystad virus was re-isolated from the lungs of infected pigs from day 2 after inoculation. Lelystad virus antigens were detected by immunohistochemical techniques in bronchiolar epithelium and alveolar cells, and in spleen cells of infected pigs from day 2 after inoculation. Ultrastructural examination of tissues by electron microscopy revealed degenerating alveolar macrophages and epithelial cells in lungs and nasal mucosa, with excessive vacuolation of the endoplasmic reticulum. Although the respiratory tract seems to be the target organ for this virus, macrophages in other organs, such as the spleen, can also be infected. This preference for macrophages may impair immunological defences.     

Histological Evaluation of Selected Organs of the Eurasian Beavers (Castor fiber) Inhabiting Poland

There is a general scarcity of data on the histological structure of major organs in the Eurasian beaver (Castor fiber). This study presents the histological characteristics of beaver organs such as the liver, spleen, cardiac muscle, lungs and kidneys. Tissue samples were collected from 21 beavers and analysed. Selected samples of tail tissue were additionally examined. Tissue samples were placed in neutral buffered formalin and embedded in paraffin. 4‐μm‐thick sections were stained with haematoxylin and eosin, and other staining techniques were also used. Scant amounts of inter‐lobular connective tissue were found in the liver. Ion or copper deposition was not observed, but scattered cytoplasmic glycogen deposits were present in hepatocytes. Our results suggest that beavers have defensive rather than storage spleens. Interestingly, the presence of melanin in splenic red pulp was noted. The histological structure of the examined organs closely resembled that of other rodent species. According to our knowledge, this is the first study evaluating the histological structure of beaver organs. Nevertheless, precise characterization of the evaluated organs requires further work with the involvement of accurate and reliable techniques, such as molecular biology or electron microscopy methods.     

Chicken leptin: properties and actions

Chicken leptin cDNA shows a high homology to mammalian homologous, with an expression localized in the liver and adipose tissue. It is noteworthy, that the hepatic expression is most likely associated with the primary role that this organ plays in lipogenic activity in avian species. As in mammals, chicken leptin expression is regulated by hormonal and nutritional status. This regulation is tissue-specific and with a high sensitivity in the liver compared to adipose tissue. The blood leptin levels are regulated by the nutritional state with high levels in the fed state compared to the fasted state. The recombinant chicken leptin markedly inhibits food intake as reported in mammals, suggesting the presence of an hypothalamic leptin receptor. The chicken leptin receptor has been identified and all functional motifs are highly conserved compared to mammalian homologous. Chicken leptin receptor is expressed in the hypothalamus but also in other tissues such as pancreas, where leptin inhibits insulin secretion and thus may have a key role in regulating nutrient utilization in this species.     

Comparative studies on the distribution and population of immunocompetent cells in bovine hemal node, lymph node and spleen

The distribution and population of immunocompetent cells in bovine hemal node, mesenteric lymph node and spleen were analyzed comparatively by immunohistochemistry and flow cytometry. Many CD8(+) cells, CD172a(+) cells and γδ T cells were found in the lymphatic cord along the sinus of the hemal node and the splenic red pulp. A few CD8(+) cells and γδ T cells were distributed diffusely in the paracortex and medullary cord of the mesenteric lymph node. Many germinal centers were recognized in the lymphatic regions such as the cortex and white pulp of these lymphoid organs. The populations of CD8(+) cells and γδ T cells in the hemal node and the spleen were higher than those of the mesenteric lymph node. In addition, the populations of CD21(+) cells and MHC class II(+) cells in the hemal node and the mesenteric lymph node were higher than those of the spleen. The results suggest that the hemal node has an important role in both cellular and humoral immunity as well as the lymph node and the spleen in cattle.     

Proline-arginine rich (PR-39) cathelicidin: Structure,expression and functional implication in intestinal health

Proline-Arginine-39 (PR-39) is a small cationic, proline and arginine rich, cathelicidin that plays an important role in the porcine innate immune system. Although PR-39 was first discovered in intestinal cell lysates of pigs, subsequent research has indicated that it is primarily expressed in bone marrow and other lymphoid tissues including the thymus and spleen, as well as in leukocytes. Mature PR-39 cathelicidin has anti-microbial activity against many gram-negative and some gram-positive bacteria. PR-39 is also a bridge between the innate and adaptive immune system with recognized immunomodulatory, wound healing, anti-apoptotic, and pro-angiogenic functions. The purpose of this review is to summarize our current knowledge about the structure, expression, and functions of PR-39 and its potential to promote intestinal homeostasis. This understanding is relevant in the search of alternative therapeutics against diarrheic enterocolitis, a major problem faced by pork producers both in terms of costs and risk of zoonosis.     

The guinea fowl spleen at embryonic and post-hatch periods

The spleen of the guinea fowl was bean-shaped but without a dented hilus. It is supplied by three short arteries that came from the ventral surface, two on the cranial end and one at the caudal end of the organ. The whole organ had a thin but tough capsule covering the outer surface except at the point of entry of the blood vessels. By day 18 of incubation, the spleen had a thin but well-defined capsule and internal to this been complete network of sinusoids filled with erythrocytes, lymphocytes and granulocytes. By day 19, dark and light staining zones, which could be termed red and white pulps, had appeared. By day 20, the granulocytes with a lot of granules within their cytoplasm, had become the biggest-sized cells in the spleen. At day 21, arteries and veins were noticed clearly in the spleen and many lymphocytes, few granulocytes and reticular cells surrounded these. Red pulp with its sinusoids was now distinct. A giant cell containing three nuclei was seen within the red pulp. At day 1 post-hatch, the capsule was at its greatest thickness so far and muscle cells were seen at the inner most part of the capsule. Granulocytes that had been a constant feature suddenly disappeared. At day 5, the small lymphocytes had dominated the large and medium-sized ones. By 2 weeks, the red and white pulps were virtually equal in distribution but by 3 weeks, the red pulp was convincingly greater. By 7 weeks, plasma cells had appeared in the peripheral splenic cords. Monocytes were observed in the sinusoids. Two germinal centres were identified for the first time in week 13 post-hatch.     

哺乳动物免疫球蛋白重链恒定区基因研究进展

免疫球蛋白分子是由2条相同的重链和2条相同的轻链所构成的多肽链结构,其中重链有5种,与之相应的免疫球蛋白分子为5类,整个免疫球蛋白分子可分为恒定区和可变区2部分。由于免疫球蛋白重链恒定区在免疫过程中起多种效应作用,目前已对多种动物的免疫球蛋白重链恒区基因进行了研究,如哺乳动物、鱼类、两栖类、爬行类、鸟类等。了解哺乳动物免疫球蛋白的结构、功能起到了重要的作用,也对了解免疫系统的起源和进化提供依据。