细菌CpG-DNA免疫刺激活性研究进展

脊椎动物的免疫系统之所以能够对细菌、病毒等微生物感染迅速作出反应 ,有赖于免疫系统对微生物结构成分的准确识别。细菌的许多成分都能激活免疫反应 ,如脂多糖(L PS)、肽聚糖、胞壁酸、甲酰基甲硫氨酸等 [1 ] 。近年来发现 ,细菌 DNA也具有很强的免疫刺激活性。有关研究显示     

Steroids as local regulators of ovarian activity in domestic animals

The presented overview gives clear evidence for steroids as local regulators of follicular and luteal activity. In the follicle, estrogen receptor-alpha (ERalpha) and ERbeta expression are demonstrated in cow, ewe and pig. Besides species specific effects in general, there is evidence that estradiol-17beta (E(2)) exerts a dose-dependent inhibition on the secretion of progesterone (P(4)) by both theca interna cells (TI) and granulosa cells (GC). GC enhance the ability of the TI to produce androstendione by supplying them with progestin precursor. Androgen produced by TI enhances the ability of the GC to make E(2), and high concentrations of E(2) in the preovulatory follicle inhibit 3beta-HSD in both TI and GC and thus, may promote the use of the pathway Delta(5) for TI androgen production. The authors suggest that E(2) acts within the follicle to exert positive feedback on androgen and E(2) production, and exerts mitotic and anti-atretic or anti-apoptotic effects on follicular cells. Parts of the E(2)-mediated local action are regulated by stimulating effects on hormone receptors (LH, FSH, oxytocin). Gap junctions permit transfer of nutrients and cytokines to and from the avascular GC and oocyte, and formation is stimulated by estrogens. In bovine corpus luteum (CL) there is evidence that P(4) may directly regulate the production of P(4), oxytocin and prostaglandins (PGs) in a cycle dependent fashion. In most of domestic animal species, there is clear evidence for CL production of E(2) with clear stimulatory and luteotropic effects on P(4), and an intraluteal circuit that involves paracrine effects of E(2), oxytocin and PGF(2alpha) (especially in pigs). In contrast, there are species (ruminants, mares) in which the evidence for important local effects of E(2) is less clear, although expression of ERalpha, ERbeta and progesterone receptor (PR) is documented. Progesterone is very important for the regulation of CL lifetime by effects on the endometrium and release of the luteolytic signal PGF(2alpha). In conclusion, steroids as local regulators of ovarian activity are now documented and may stimulate further research in this field.     

In vivo immunostimulatory effects of CpG oligodeoxynucleotide in cattle and sheep

Oligodeoxynucleotides (ODN) containing cytosine-phosphate-guanosine (CpG) motifs have been shown to activate the innate immune system and protect mice and chicken from bacterial and viral infections. Unfortunately, similar studies in other veterinary species are lacking. In this study we assessed the in vivo immunostimulatory effects of CpG ODN 2007, an ODN with previously demonstrated in vitro biological activity. The in vivo effects of ODN 2007 were compared in two closely related outbred species, sheep and cattle, to determine if there were common biological responses. We demonstrated that subcutaneous (s.c.) injection of the CpG ODN induces an acute phase response in the form of a transient fever, a mild transient increase in circulating neutrophils and elevated serum haptoglobin in both sheep and cattle. Sheep injected with CpG ODN also exhibited increased serum 2'5'-oligoadenylate (2'5'-A) synthetase activity, but no increase in serum 2'5'-A synthetase was detected in cattle. The ODN-induced responses were stronger in animals injected with CpG ODN formulated in 30% emulsigen than phosphate buffer saline (PBS) alone. These in vivo data demonstrate for the first time that a CpG ODN induces acute phase immunostimulatory responses in sheep and cattle. However, CpG ODN-induced antiviral effector molecule 2'5'-A synthetase was detected only in sheep but not in cattle.     

Protection of neonatal broiler chicks against Salmonella Typhimurium septicemia by DNA containing CpG motifs

Oligodeoxynucleotides (ODN) containing cytosine-phosphodiester-guanine (CpG-ODN) motifs have been shown to stimulate the innate immune system against a variety of bacterial and protozoan infections in a variety of vertebrate species. The objective of this study was to investigate the immunostimulatory effect of CpG-ODN in neonatal broilers against Salmonella Typhimurium septicemia. Day-old broiler chicks, or embryonated eggs that had been incubated for 18 days, received 50 microg of CpG-ODN, 50 microg of non-CpG-ODN, or saline. Four days after exposure to CpG-ODN or day 2 posthatch, 1 x 10(6) or 1 x 10(7) colony-forming units (cfu) of a virulent isolate of Salmonella Typhimurium was inoculated by the subcutaneous route in the neck. Clinical signs, pathology, bacterial isolations from the air sacs, and mortality were observed for 10 days following challenge with Salmonella Typhimurium. The survival rate of birds in groups receiving either non-CpG-ODN or saline following Salmonella Typhimurium infection was 40%-45%. In contrast, birds receiving CpG-ODN had significantly higher survival rate of 80%-85% (P < 0.0001). Bacterial loads and pathology were low in groups treated with CpG-ODN compared to the groups receiving saline or non-CpG-ODN. Colony-forming units of Salmonella Typhimurium in the peripheral blood were significantly lower in birds treated with CpG-ODN compared to the group that received saline. This is the first time that CpG-ODN has been demonstrated to have an immunoprotective effect against an intracellular bacterial infection in neonatal broiler chickens following in ovo delivery.     

壳聚糖的生物活性及其在水产动物中的研究进展

壳聚糖是甲壳素脱乙酰基后得到的一种带正电荷的高分子碱性多糖。甲壳素广泛存在于低等动物尤其是节肢动物（如虾、蟹和昆虫）外壳中,也存在于真菌和藻类细胞壁中。全世界每年蟹、虾和龙虾等水产品加工后的甲壳废弃物有100多万t．其中含有10％～30％甲壳素。     

CEA test in domestic animals

In human cancer treatment, CEA (carcino embryonic antigen) testing is a routine procedure, even though the test is of low sensitivity (40%) and low specificity (70%). Since tests with polyclonal antibodies render no reproducible results with animal sera, the applicability of a recently available monoclonal CEA test designed for human sera was evaluated. We were able to show that the latter test was of supplemental diagnostic value when testing animal sera. The upper normal limit for dogs is 1.65 ng/ml, for cats 2.81 ng/ml, for cows 2.85 ng/ml, for sheep 2.85 ng/ml and for horses 1.61 ng/ml.     

Iron deficiency in domestic animals

Iron is essential for the organism. In ionized forms (Fe++, Fe ), it constitutes an integrated part of a lot of different functional proteins (Figure 1). The most important functions are participation in oxygen transport in blood, oxygen storage in muscle tissues and oxidation of nutrients in the mitochondria. Iron is an essential part of cytochrome C and alpha-glycerolphosphate dehydrogenase, and early stages of iron deficiency may, therefore, cause disturbances in tissue metabolism before development of anaemia. Thus, haemoglobin determinations is not very suitable for diagnosing early iron deficiency. The content of iron in roughages, apart from root crops (Table II), is usually sufficient to cover the requirement of domestic animals (Table III), which is met by about 50 mg per kg feed dry matter. Iron deficiency is very often caused by a reduced absorption in the intestinal tract because of components in the feed forming complexes with iron of very low solubility or inhibitors reducing the absorption processes. The immune status of the organism and its resistance against infections depends on the iron supply. Iron deficiency inhibits the myeloperoxidase activity and thus decreases the bacteriocide effect of the leucocytes. In spite of this, when exposed to infections the physiological mechanisms reduce the blood concentration of available iron. By this mode of action, invading pathogens, needing iron like the host animals, will be restrained. The low content of iron in milk (Table II) combined with a high content of iron binding lactoferrin, is ideal to protect newborn and milk fed young animals against intestinal infections.(ABSTRACT TRUNCATED AT 250 WORDS)     

Herpesviral abortion in domestic animals

Abortion or neonatal disease may follow infection with several α, β and γ-herpesviruses. The α-herpesvirus, equid herpesvirus-1 (EHV-1), causes single or epizootic abortions or neonatal deaths in equids, and the closely related virus EHV-4 causes sporadic equine abortions. In cattle, the α-herpesviruses, bovine herpesvirus-1 (infectious bovine rhinotracheitis virus) and bovine herpesvirus-5 (bovine encephalitis virus), and a γ-herpesvirus, bovine herpesvirus-4, have all been implicated as causes of abortion. In pigs, suid herpesvirus-1 (SHV-1: pseudorabies virus), an α-herpesvirus, and SHV-2 (porcine cytomegalovirus), a β-herpesvirus, each cause abortion or neonatal piglet losses. Caprine herpesvirus-1, canine herpesvirus and feline herpesvirus-1, all α-herpesviruses, cause abortions or neonatal deaths in goats, dogs and cats, respectively. This review discusses the pathogenesis, pathology and laboratory diagnosis of these herpesviral abortions and neonatal diseases, with an emphasis on experimental studies of each disease. Alternative reviews covering other aspects of each infection, such as the genetic and antigenic structure of the viruses, host immune responses and approaches to vaccination and disease control are indicated at appropriate points in the text. nts in the text.