Immune Defence Organs Research Articles

Histoarchitectonics of the Harderian gland of chickens in the post-vaccination period

Understanding the effect of vaccination on the body of chickens is impossible without exploring the morphology of the immune defence organs. The purpose of the study was to identify morphological changes in the Harderian gland of the Haysex Brown chickens aged 1, 15, 25, 50, 75, 100 and 120 days under the influence of vaccination. The following methods were used in the study: anatomical, histological, light-optical, morphometric, and statistical. Histological preparations of the Harderian gland of chickens of different ages (1, 15, 25, 50, 75, 100 and 120 days) of the vaccinated and unvaccinated groups were analysed. The features of the organ structure, its lymphoid structures and their types of forms were explored on histological preparations of the chicken Harderian gland. According to histological studies, it was established that this is a complex tubular lobular gland, which consists of secretory lobules with ducts. The interlobular connective tissue contains a significant number of lymphocytes, plasma cells, and other cells. In vaccinated chickens at 25 days of age, the presence of diffuse lymphoid tissue was noted, which was not observed in the control group, and at 50 days of age - the development of a nodular form of lymphoid tissue, the maximum number of which was observed at 100 days of age. In chickens of 75, 100, and 120 days of the age of the experimental group, the amount of lymphoid tissue in the Harderian gland increased, which was noted in the interlobular connective tissue and secretory lobules. It has been proven that the chicken gland, as a peripheral organ of immune defence, is developed at 50 days of age in both the control and vaccinated groups. The study of morphological changes in the Harderian gland of the poultry of different ages is an important tool for the development of preventive vaccination protocols in modern poultry farming. The results of the study should be considered when improving the technology of rearing and exploitation of chickens to ensure high vitality and, accordingly, productivity

The effect of vaccination on the live weight of chickens and the absolute weight of the spleen and gland

Choosing optimal chicken immunization programs is an urgent problem in poultry farming. Studying the morphology of the organs of the chickens' immune system allows you to objectively assess the effectiveness of prevention methods. The article provides data on the effect of multiple vaccinations on the live weight of chickens and the absolute weight of immune defense organs: the spleen and gland of chickens aged 1, 15, 25, 50, 75, 100, and 120 days. One of the leading indicators of the growth of young birds is the dynamics of live weight under the influence of external factors. Identical technological conditions at the beginning of the experiment and the selection of livestock according to the principle of analogs in groups made it possible to assess the effect of vaccination on the chickens' bodies based on live weight indicators. According to our research results, it was established that in chickens of 100- and 120-day-old age, with multiple vaccinations, there is a probable increase in live weight indicators compared to the control group of animals. Our research showed that by 25 days in chickens (vaccinated six times), the hands of the absolute mass of the spleen practically did not change. At the same time, in 25-, 100-, and 120-day-old chickens, there is an increase in the absolute mass of the spleen and the gland at 15- and 50-day-old compared to the indicators of non-vaccinated animals. This indicates the implementation of immune reactions in the studied organs of immune protection due to increased migration of T- and B-lymphocytes to them. In addition, if age periods are compared, a decrease in the absolute mass of the Garder gland was found in 75-day-old chickens compared to 50-day-old chickens, which indicated the involutional processes of this gland. The maximum parameters of the gland's absolute mass were found at 50 days in chickens of both the vaccinated and non-vaccinated groups. Thus, in vaccinated chickens, this indicator of the gland was 0.095 g. Organometric changes in the spleen and gland of vaccinated chickens can be one of the criteria for diagnosing poultry immunodeficiencies.

Toxic effect of the titanium dioxide rutile form on the morphological characteristics of the immune system organs

The aim. To study the effect of the rutile form of titanium dioxide upon its oral administration on the morphological and functional state of the organs of the immune system of rats. Materials and methods. In this work, using classical morphological approaches and specific markers: proliferation - Ki-67, PCNA, apoptosis - protein p53 and macrophages - CD68, which make it possible to adequately identify not only the cells themselves, but also their functional state, a study of the spleen and thymus of rats after oral administration (10 mg/kg animal body weight, 28 days) of a nanodispersed form of TiO2 (rutile form, 40-60 nm) obtained by diluting TiO2 powder in distilled water was carried out. Aggregation of nanoparticles was prevented by treatment of a suspension of nanodispersed TiO2 in an ultrasonic bath. Rats of the control group were orally administered with distilled water in the same volume. Results. With oral administration of the rutile form of nanodispersed TiO2, a moderate accidental involution of the thymus is observed, a reduction in the white pulp of the spleen, due to a decrease in the proliferative potential and an increase in apoptosis. The revealed morphofunctional changes in lymphoid organs can be interpreted from the standpoint of induced secondary immunodeficiency that develops against the background of exposure to rutile TiO2 NPs. Limitations. When studying the effect of titanium dioxide (rutile, 40-60 nm, 10 mg/kg of animal body weight) on the morphological characteristics of the immune defense organs, the sample size was 12 Wistar rats, the maximum duration of exposure was 28 days. Conclusion. The detected morphofunctional changes in the lymphoid organs can be interpreted from the position of induced secondary immunodeficiency, developing against the background of exposure to NPS TiO2 of the rutile modification.

Influence of systemic inflammation predictors on the premature labor of hiv-infected women living in Subarctic region

The goal is to conduct a comparative analysis of the characteristics of blood counts of pregnant women with HIV living in the subarctic climatic zone of the Khanty-Mansiysk District, as predictors of a systemic inflammatory reaction on the background of infection and pregnancy complicated by preterm delivery.Material and methods. A retrospective analysis of 78 stories of pregnant women with HIV (main group II) was carried out, in 2016–2018. observed in one antenatal clinic in the city of Surgut. Control group (I) comprised 20 histories of pregnant women without HIV. Clinical-anamnestic and blood parameters were compared, including indicators of T-helpers, T-suppressors and viral load, leukocyte intoxication indices, hemoglobin, erythrocytes and platelets by trimesters of pregnancy. The material was processed using the Statistica-10 software system. The critical level of statistical significance was taken at p<0,05.Results. A comparative analysis of blood counts of pregnant women living in the subarctic region showed a relationship between the preterm labor of patients with HIV with a progressive decrease in the T-cell level of immunity, an increase in the level of lymphocytes and leukocyte blood indices, a decrease of hemoglobin, erythrocytes, platelets, against the background of persisting viral load for the remainder of pregnancy. A decrease of T-lymphocyte counts indicates the development of a systemic inflammatory response on the background of HIV infection, depletion of the immune defense organs and the progression of the disease, while a low level of CD4 lymphocytes stimulates the activation of granulocytes in the blood and indicates further depletion of T-lymphocytes. Activation of a systemic inflammatory response that promotes the release of inflammatory mediators and prostaglandins and, with a high probability, underlies the mechanisms of rejection of the fetus and placenta and the spontaneous preterm labor. The comorbid background of pregnant women with HIV and preterm labor is associated with low adherence to HAART therapy and high detectable viral load throughout gestation.

Особенности гематологических показателей байкальского омуля в естественных и лабораторных условиях

As a result of investigation, of the leucocytic formula and ratio of immune defense organs cells (head kidney and spleen) for fishes Baikalian omul in aquarium and natural conditions of spawning migration were determined. The blood of young omul is comprised by the relatively high number of low-differentiated neutrophil granulocytes and monocytes. The total number of lymphocytes varied in the range 44–99 %, and the mean value was 69 %. Based on the methods of the morphologic and tinctorial distinguishing the eosinophil, neutrophil and basophil cells there were detected in the peripheral blood smears, head kidney and spleen prints. The average ratio of lymphocytes in the head kidney of mature individuals is 74.41 %, and the ratio of macrophages is higher than in juveniles and its average value is 2.25 %.

Мікроскопічна будова серця, органів кровотворення та імунногенезу собак за експериментального відтворення парвовірозу

A fairly common disease of dogs in Ukraine is parvovirus enteritis, which is extremely common (51.6%) among enteritis of viral etiology and causes significant economic and moral damage to pet owners. Therefore, the need for additional studies to clarify, supplement and summarize data on the pathology of various organs and tissues in parvovirus enteritis in dogs, modern methods of immunoprophylaxis and treatment can significantly reduce morbidity and mortality for this infection. Given the relevance of the topic, the result of our study is the refinement, addition and synthesis of data on the pathomorphology of various organs and tissues of dogs during experimental reproduction of parvovirosis, which will make it possible to explain in more detail the effect of the pathogen on animals with parvovirus enteritis. The article analyzing the results of histological studies presents data on the microscopic structure of the blood-forming organs and the immune defense - the thymus, spleen, lymph nodes and the heart of dogs during experimental infection with their parvovirus enteritis. It has been established that in dogs with experimental to infect of parvovirus enteritis, microscopic changes in the hematopoietic and immune defense organs are recorded. At the same time, the most pronounced changes in the thymus are impaired lymphocyte differentiation processes in thymic lobules, lymph nodes and expansion of blood vessels and swelling of the cortex and medulla, in the spleen, pulp edema and accumulation of red granules and iron-containing pigment grains in the spleen, hemosiderin , the result of the breakdown of a large number of red blood cells. In the myocardium, microscopic changes were manifested by diffuse edema between muscle and connective tissue, granular dystrophy of cardiomyocytes and the presence of intranuclear eosinophilic taurus inclusions. The complex of histological changes in the blood-forming organs and immune defense and the myocardium that we found during experimental reproduction of parvovirosis can be considered a characteristic criterion for the pathomorphological differential diagnosis of parvovirus enteritis in dogs

The relationship between parasites and spleen and bursa mass in the Icelandic Rock Ptarmigan Lagopus muta

The spleen and bursa of Fabricius in birds are organs that play an important role in fighting parasite infections. The size of these organs can be used by ecologists as a measure of immune investment, with larger size implying greater investment. The bursa only occurs in juvenile birds during the development of the B cell repertoire, whereas the spleen, which is the main site of lymphocyte differentiation and proliferation, is present in both juveniles and adults. We investigated spleen and bursa mass in relation to parasite measures for 541 Rock Ptarmigan Lagopus muta collected in northeast Iceland during October from 2007 to 2012. Of these 541birds, 540 carried at least one parasite species. Juveniles had heavier spleens than adults, and adult females had heavier spleens than adult males, but there were no sex differences in juveniles. Spleen mass increased from 2007 to 2009, then decreased up to 2011, before slightly increasing again in 2012. Spleen and bursa mass in juveniles increased with improved body condition, but decreased in adults, and this effect differed significantly among years. Spleen mass in juveniles was positively associated with parasite species richness and abundance, in particular endoparasite abundance, with coccidian parasites being the main predictors. Bursa mass was negatively associated with elevated ectoparasite abundance, with two chewing lice being the main predictors. These two immune defense organs appeared to relate to different stimuli. Mean annual spleen mass of juveniles changed in synchrony with Ptarmigan body condition and population density over the years of this study. The only parasite measure that showed any relation to density was coccidian prevalence in juvenile birds, with an approximately 2-year time-lag, suggesting that factors other than parasites are probably more important in triggering changes in spleen mass.

Trichinella spiralis infection rapidly induces lung inflammatory response : The lung as the site of helminthocytotoxic activity

In the present work, we studied the kinetics of the appearance of different immunological parameters in the lungs during the intestinal phase of infection with Trichinella spiralis. We also evaluated the lung's role in the retention and death of this helminth in its migratory stage. To study these parameters, we used lung extracts, lung cell suspensions and rat lung tissue sections. During the intestinal phase of infection (days 0–13 post-infection, p.i.), an inflammatory response is elicited in the lungs, which reflects humoral, cellular and functional changes. These changes included an increased number of mast cells and eosinophils and the local production of IL-4, IL-5, IL-10, TNFα, IFNγ, IL-13, CCL11 and CCL28. We found hyperplasia of the bronchus-associated lymphoid tissue (BALT). Total and specific IgA, IgE, IgG1 and IgG2a were detected locally. The retention of the migratory larvae in the lung, together with the ex vivo cytotoxic capacity of the lung cells and antibodies present in the lung extracts, suggested that the lung was one of the immune defense organs against the pathogen's migration stage.

The role of parasites in ecology and evolution of migration and migratory connectivity

All organisms are adapted to their native environment, posing problems in terms of fitness costs for individuals that leave this environment. Other species constitute an important coevolving component of this native environment, with more than half of all living organisms being parasites. All host species have evolved behavioral and physiological defenses against parasitism, and all higher organisms have evolved immunity that rely on exposure to novel substances derived from other organisms (antigens) for developing efficient defenses. The evolution of dispersal must have been affected by host–parasite interactions because dispersers and migrants inevitably encounter novel parasite strains to which they are not adapted. We provide an overview of bird migration and migratory connectivity viewed in the light of host–parasite interactions. Migratory birds generally show strong site fidelity to both breeding and wintering locations, as evidenced from studies of individuals, estimates of adult survival rates based on breeding or non-breeding captures, and studies of migratory connectivity. Connectivity is closely linked to development of the immune system and regression of immune defense organs. Empirical and theoretical evidence suggests that site fidelity is under stabilizing selection, and that offspring resemble their parents in terms of site fidelity. Populations may diverge in connectivity when the fitness benefits in terms of parasitism exceed the costs. Many species of birds have evolved migratory divides from glacial and post-glacial isolation that may constitute incipient speciation linked to divergence in parasite faunas and hence in local co-adaptation of hosts and parasites in the breeding and wintering quarters. Migration may play a role in speciation when interbreeding among hosts causes divergence in fitness costs and benefits of parasitism due to local adaptation in breeding and wintering areas. These ecological and evolutionary scenarios for migration and migratory connectivity provide a number of testable assumptions and predictions that can form the basis of future research.

Feeding innovations and parasitism in birds

The rate of behavioural innovation, such as opportunistic feeding innovation, may facilitate adaptation to novel environments. Because parasites may affect how their hosts adopt novel means of resource acquisition, or because opportunistic behaviours may involve the risk of being exposed to a large parasite fauna, we hypothesize an evolutionary link between the rate of feeding innovations and parasitism. We investigated the phylogenetic relationship between relative frequency of feeding innovations (adjusted for research effort and population size) and relative size of immune defense organs (as a relative measure of parasite-mediated selection) and the prevalence of blood parasites in birds. Using generalized least squares models, we found that species with relatively large bursa of Fabricius, thymus, and spleen had higher rates of feeding innovations than species with small immune defense organs. Similarly, there was a positive interspecific association between feeding innovation and haematozoa prevalence. These relationships were not confounded by migration, relative brain size, geographical distribution, and male plumage brightness. Analyses of causality relying on evolutionary modelling of discrete variables and path analysis suggest that increasing rate of feeding innovation may place species under intense selection due to parasitism. Therefore, behavioural adaptation by feeding innovation seems to have consequences for the coevolutionary arm race between parasites and hosts. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society, 2007, 90, 441–455.

Covariation between brain size and immunity in birds: implications for brain size evolution

Parasitism can negatively affect learning and cognition, setting the scene for coevolution between brain and immunity. Greater susceptibility to parasitism by males may impair their cognitive ability, and relatively greater male investment in immunity could compensate for greater susceptibility to parasites, in particular when males have a relatively large brain. We analysed covariation between relative size of immune defence organs and brain in juvenile and adult birds. The relative size of the bursa of Fabricius and the spleen in adults covaried positively with relative brain size across bird species. The relative size of these two immune defence organs covaried with sex differences in relative size of the brain, indicating that the relationship between immune defence and brain size was stronger for males. In contrast, liver and heart size or sexual size dimorphism in size did not covary with immune defence. Thus, species in which males have relatively large brains also have relatively large immune defence organs.

Climate, body condition and spleen size in birds.

Climatic conditions may impact on the body condition of animals and thereby affect their survival prospects. However, climate may also impact directly on the survival prospects of animals by affecting the size of immune defence organs that are used for defence against parasites. We used a large long-term database on body condition and size of the spleen in birds to test for immediate and delayed relationships between climatic conditions as indexed by the North Atlantic Oscillation (NAO) and body condition and spleen mass, respectively. Across 14 species of birds, spleen mass was significantly positively correlated with the NAO index, while the delayed effect of NAO on spleen mass was not significant. Spleen mass was positively related to body condition, but body condition did not depend significantly on NAO or delayed NAO effects. Bird species with a strong positive effect of NAO on spleen mass tended to have small spleens for their body size, while species with a strong negative effect of NAO on spleen mass tended to have relatively large spleens. Since bird species with relatively large spleen have been shown to suffer more from the negative effects of parasites, we can infer that the effects of climate as indexed by NAO on the size of the spleen depends on the importance of parasite-mediated natural selection.

Dispersal, vaccination and regression of immune defence organs

The thymus in vertebrates and the bursa of Fabricius in birds regress before reproduction, while the immunological information of these organs is maintained as cell memory. Regression at a certain age presupposes that individuals have achieved exposure to a large fraction of parasites in the environment. Here we present a new scenario for regression of immune defence organs, based on optimality reasoning. This scenario links early involution of immune defence organs with (1) effects of exposure to parasites on adaptive immune responses to these parasites, (2) exposure to local parasite communities during natal dispersal and migration as a means of “vaccination” against local parasites, and (3) the function of visits to future breeding sites by juveniles as a means of exposure to local parasites. This scenario provides explanations for why natal dispersal is longer than breeding dispersal, for sex differences in dispersal, and for why the bursa of Fabricius regresses relatively early in life among bird species with delayed start of reproduction.

Host immune defence and migration in birds

Migratory birds are exposed to at least two different parasite faunas during their annual cycle, while resident birds only experience a single parasite fauna. Migratory birds should therefore have evolved mechanisms to control or reduce the negative impact of infections from a more diverse parasite fauna. In a comparison of pairs of closely related species of birds that differ with respect to whether they are migratory or residents, the size of two immune defence organs (the bursa of Fabricius and the spleen) was consistently larger in the migratory species. Since the bursa is only found in juvenile, sexually immature birds, we conclude that immune defence adaptations to the impact of a more diverse parasite fauna in migrants already exist before the start of the first migration. Interspecific differences in investment in immune defence between migratory and resident birds have implications for our understanding of complex host–parasite interactions, the acquisition of new hosts by parasites, and the susceptibility of migratory birds to environmental perturbations.

Condition, Disease and Immune Defence

Life-history traits and secondary sexual characters often demonstrate condition-dependence, and reproductive success thus ultimately appears to be determined by condition. Here we test the hypothesis that anti-parasite defence is condition-dependent and thus ultimately limits fitness. Animal hosts defend themselves against parasites by an efficient immune system that changes its activity level depending on level of infection. Since immune function is costly, as demonstrated by several field studies, we predicted that large immune defence organs should be maintained when the costs of an elevated immune response were reduced, or when the benefits were increased. Hence, the size of immune defence organs was predicted to increase in response to disease due to increased benefits of investment in immune function, and the size was predicted to increase in response to high body condition because of reduced costs of investment in immune function. A comparative study of birds demonstrated that the size of the spleen was significantly increased among individuals suffering from parasitic infections and signs of disease as compared to healthy individuals. Furthermore, we found evidence for a positive association between spleen size and body condition. These findings are consistent with the hypothesised cost of immune function and hence a cost of anti-parasite defence.

Sexual Dimorphism in Immune Defense

Sex differences in parasitism are common and may depend on sex differences in intensity of sexual competition, immunosuppression, or exposure to parasites. We used a large data set on the mass of two immune defense organs in birds (the bursa of Fabricius and the spleen) to test for consistent sex differences in immune defense. Males had a relative spleen mass that was consistently smaller, but more variable, than that of females across species of birds. A sex difference in the size of the spleen was not present among juveniles but was large and statistically significant among adults. The suppression of spleen mass in adult males increased with a measure of intensity of sexual selection: the frequency of extra-pair paternity. These findings suggest that sex differences in parasitism may arise as a consequence of sex differences in immune function, as mediated by sexual selection.

Sexual Dimorphism in Immune Defense

Sex differences in parasitism are common and may depend on sex differences in intensity of sexual competition, immunosuppression, or exposure to parasites. We used a large data set on the mass of two immune defense organs in birds (the bursa of Fabricius and the spleen) to test for consistent sex differences in immune defense. Males had a relative spleen mass that was consistently smaller, but more variable, than that of females across species of birds. A sex difference in the size of the spleen was not present among juveniles but was large and statistically significant among adults. The suppression of spleen mass in adult males increased with a measure of intensity of sexual selection: the frequency of extra‐pair paternity. These findings suggest that sexdifferences in parasitism may arise as a consequence of sex differences in immune function, as mediated by sexual selection.

Immune defence, extra–pair paternity, and sexual selection in birds

Secondary sexual characters have been suggested to reliably reflect the ability of individuals to resist debilitating parasites, and females may gain direct or indirect fitness benefits from preferring the most extravagantly ornamented males. Extra–pair paternity provides an estimate of an important component of sexual selection in birds. Species with a high frequency of extra–pair paternity have a variance in realized reproductive success that is greater than the variance in apparent reproductive success, and extra–pair copulations and hence extra–pair paternity by females are often directly associated with the expression of male secondary sexual characters. If sexually dichromatic species have experienced a long period of antagonistic coevolution with their parasites, such species should have evolved larger immune defence organs than sexually monochromatic species. Bird species with sexual dichromatism had larger spleens for their body size than monochromatic species in a comparative analysis. Furthermore, species with a high frequency of extra–pair paternity were sexually dichromatic and had large spleens for their body size. These results are consistent with the hypothesis that females of dichromatic bird species seek extra–pair copulations to obtain indirect fitness benefits in terms of superior resistance of their offspring to virulent parasites.