Changes In Lymphoid Organs Research Articles

Structural changes in the organs of the lymphoid system in terms of induced carcinogenesis

Colorectal cancer is the third most common cancer in the world. Despite recent therapeutic advances, it causes more than 500,000 deaths each year. The immune system plays a crucial role in protecting the body from cancer. However, cancer cells are able to evade immune detection and destruction. For example, they can downregulate antigen expression, produce immunosuppressive molecules, or recruit immune cells that perform regulatory or inhibitory functions. Understanding the complex interactions between the immune system and carcinogenesis is crucial for developing effective cancer treatments. The study aimed to determine the morphological changes in the thymus, spleen, and lymph nodes under N,N-dimethylhydrazine-induced carcinogenesis. The study was performed on 77 male outbred albino rats weighing 190-230 g, kept in standard vivarium conditions. Colon adenocarcinoma was modeled by administration of N,N-dimethylhydrazine hydrochloride for 30 weeks. To study the peculiarities of morphological and functional changes in lymphoid organs in the dynamics of colon tumor lesions, animals were withdrawn from the experiment every 30 days. Paraffin sections of the thymus, spleen, and lymph nodes 5-6 μm thick were made on a rotary microtome and stained with hematoxylin and eosin. The experimental investigation unveiled the character and extent of histological alterations within the lymphoid system organs under conditions of N,N-dimethylhydrazine-induced colon adenocarcinomatosis. As the experiment progressed, there was a noticeable escalation in the severity of detrimental and degenerative modifications observed in the thymus, spleen, and lymph nodes. These modifications were evident in the disruption of blood circulation within the examined organs, leading to vascular wall impairment and hemorrhaging, the disarray of morphofunctional elements and the development of fibrosis. Given the significant role played by the thymus, spleen, and lymph nodes in regulating carcinogenesis and maintaining immune balance, it is extremely important to delve into understanding the changes in their structure and function. Obtained results indicate that carcinogenesis is accompanied by pronounced morphological changes in the structural components of the lymphoid system organs, the degree of which increases in direct proportion to the duration of exposure to the oncogenic factor.

Systemic impact of melanoma on bone marrow-derived immune cells

Abstract Melanoma accounts for the most skin cancer-related deaths in the United States. As patients age, antitumor responses decline, making age a negative independent prognostic factor of overall survival in melanoma. Delving into age-associated changes in lymphoid organs, such as increased bone marrow (BM) adiposity, could improve the understanding of the aged antitumor response. We hypothesize that the age-related increase in BM fat drives the functional decline of immune cells, ultimately hindering the systemic antitumor response to melanoma. We utilized flow cytometry to analyze melanoma and age-related alterations to the BM, blood, and tumor immune cell composition. Our preliminary data suggests that mice challenged with melanoma systemically increased granulocytes. However, only aged tumors had an increase in granulocyte infiltration. Meanwhile, T cells significantly decreased in the BM of tumor-bearing mice. Additionally, there was a significant increase in lipids in the BM T cells from non-tumor-bearing aged mice and a reduction in these lipids when mice were challenged with tumor. Thus, there appears to be an age-dependent systemic immune response when the mice are burdened with melanoma. As a future direction, we plan to investigate the role of the aged BM niche on the effectiveness of immunotherapies. These insights could lead to improved outcomes for elderly patients with melanoma.

Sarcoidosis-related autoimmune inflammation in COVID-19 convalescent patients.

Currently, there are a large number of reports about the development of autoimmune conditions after COVID-19. Also, there have been cases of sarcoid-like granulomas in convalescents as a part of the post-COVID-19 syndrome. Since one of the etiological theories of sarcoidosis considers it to be an autoimmune disease, we decided to study changes in the adaptive humoral immune response in sarcoidosis and SARS-CoV-2 infection and to find out whether COVID-19 can provoke the development of sarcoidosis. This review discusses histological changes in lymphoid organs in sarcoidosis and COVID-19, changes in B cell subpopulations, T-follicular helper cells (Tfh), and T-follicular regulatory cells (Tfr), and analyzes various autoantibodies detected in these pathologies. Based on the data studied, we concluded that SARS-CoV-2 infection may cause the development of autoimmune pathologies, in particular contributing to the onset of sarcoidosis in convalescents.

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.

Ochratoxin A occurrence, its pathological effects on poultry health and decontamination approaches

Mycotoxins are filamentous fungi which can be seen microscopically and they impart adverse effects on poultry health. The occurrence of mycotoxins in poultry feed imparts adverse effects not only to the birds’ health but also causes huge economic losses by affecting feed conversion ratio, production of meat and eggs,and also responsible for histopathological changes in lymphoid organs of chicken. More than 300 different species of mycotoxins have been reported from which the ochratoxin and aflatoxins are the most harmful for poultry industry. Among ochratoxins, especially the Ochratoxin A (OTA) is produced from Aspergillus Ochraceus and and Penicillium verrucosum species as storage fungi inside stored drains and feed ingredients. The ochratoxicity is a dose-dependent factor and hits the immune system of birds besides decreased feed intake and decreased body weight. Higher doses of OTA toxicity resulted in deterioration of egg shell quality and hatchability in layers and breeders. Histopathological profile of ochratoxicity affected birds showed severe to moderate changes in the kidney, bursa of Fabricius, liver, thymus, spleen, heart, and lungs depending on dosage. In this review article, an attempt has been made to concise the OTA associated alterations in growth pattern, production index, biochemical changes and histopathological profile of the poultry. The current approaches and agents (Vitamin-E, Silymarin), which are being used to reduce the effects of OTA toxicity in birds, have also been discussed.

Trial to control infectious bursal disease virus using iron oxide chitosan nanocomposite in broiler chicken

The present study attempted to control infectious bursal disease virus (IBDV) with iron oxide chitosan nanocomposite as an antiviral compound. The iron oxide chitosan nanocomposite was prepared using the co-precipitation method and characterized by high-resolution transmission electron microscopy (HR-TEM) and cytotoxicity assay on Vero cells. To evaluate the effectiveness of iron oxide chitosan nanocomposite against IBDV, eighty 21-day-old Baladi broiler chicks were divided into four groups (G1-G4). Chicks kept in G1 served as a negative control, while chicks kept in G2 (challenged-non-treated) were challenged orally with IBDV 103EID\50/bird). Chicks kept in G3 (challenged-treated) were challenged orally with 1103EID\50 IBDV/bird and received 1 mL of iron oxide chitosan nanocomposite (1 mg dissolved in 100 mL water) for three days post-inoculation (PI) while chicks kept in G4 (non-challenged-treated) received the same dose of iron oxide chitosan nanocomposite for three successive days. The effectiveness of iron oxide chitosan nanocomposite was assessed based on clinical signs, mortalities, postmortem lesions, and viral RNA load in the bursa of Fabricius samples at the 3rd, 6th, and 9th days PI by isolation onto specific pathogen-free embryonated chicken eggs (SPF-ECE) and histopathology. Results revealed that the average particle size of iron oxide chitosan nanocomposite size was found to be 35.1±5 nm. The selected particles exhibited zeta potentials of 16.8±10.9 mV, polydispersity index of 0.91, and iron concentration of 2,625 mg/L. Chicks kept in G2 showed severe clinical signs, including anorexia, ruffled feathers with droopy wings, prostration, and whitish mucoid diarrhea with a mortality rate of 30%. Other groups showed no specific mortalities. The IBDV bursal load was significantly lower (P<0.05) in the challenged-treated chicks (0.5-1 log10) compared to the challenged-non-treated group (3-6.4 log10). Histopathological lesions of the bursa, spleen, thymus, and kidney in the challenged-treated group showed hyperactivity of the lymphoid population compared to necrosis and depletion of lymphoid elements in the challenged control group at the 6th days PI. Based on the current study, iron oxide chitosan nanocomposite showed a promising antiviral activity that could significantly reduce IBDV load in the bursa and decrease pathological changes in lymphoid organs.

A Single Gene-Mediated Perturbation of the Human Genome Leads to Malignant Transformation in a Murine Transgenic Model

We hypothesized that induction or activation of a gene that directly affects DNA integrity can provide a tool for ongoing genomic changes in a cell and may eventually lead to oncogenesis. In the human genome, apurinic/apyrimidinic (AP) sites are created by number of external and internal factors including exposure to chemicals, UV radiation, DNA damaging agents, reactive oxygen species (ROS), DNA glycosylases and/or spontaneous hydrolysis by other mechanisms. AP sites are pre-mutagenic lesions that can also affect normal DNA replication. An evolutionarily conserved mechanism “base excision repair (BER)” has been established to identify and repair such sites. As part of BER, AP nucleases cleave the phosphodiester backbone at 5' to the AP site, prior to its repair. Although APEX 1 and 2 are the nucleases required for this repair, their hyperactivity has been connected with increased DNA breaks. We have previously observed that over expression of either APEX 1 or APEX 2 leads to malignant transformation with number of genomic changes including copy number alterations, single nucleotide variants (SNVs) and structural changes.In this study, we investigated if transgenic overexpression of APEX2 in B cells in mice will cause tumorogenesis. We specifically overexpressed APEX2 in B cells by generating Tg,CD19Cre+/-,APEX2+/- mouse lines and used Tg,CD19Cre+/- mouse (siblings of trail group) as control. The expression of APEX2 was detected by immunohistochemical (IHC) staining, which confirmed specific expression of APEX2 in lymph nodes. We next evaluated impact of APEX2 expression on B cell genome. We isolated B220+ B cells from spleen of 8 weeks old mice, and identified both increased single strand break (SSB) and double strand breaks (DSB). After 45 weeks of age and at variable times thereafter, 40% (23/58) of Tg,CD19Cre+/-,APEX2+/- mice showed enlargement of the lymph nodes and spleen. Histology showed effacement of normal tissue architecture by a nodular or diffuse population of atypical lymphoid cells in interfollicular areas. A distinct pattern of B220+BCL6+CD5- B-cell lymphomas were identified after IHC staining, which resemble human diffuse large B-cell lymphoma (DLBCL). To investigate the changes at genomic level, we performed whole genome sequencing of tumor tissues from 3 mice as well as heart tissues (with lowest APEX2 expression) from the same mice to be used as controls. From single nucleotide varients (SNVs) calling, we observed average of 24,388 SNVs in the tumor with acquisition of new copy number changes and significant number of structural variants including average of 43 translocations, 51 deletions, 21 duplications and 24 inversion. Indel frequency was variable with average of 348. We observed mutational hotspots on chr6, chr12 and chr16. Variant allele frequency (VAF) data shows clonality of chr11 related mutations. We observed most frequent T>G, and then T>C mutations in all 3 samples. Interestingly, the mutational signature analysis showed signature 17 accounting for an average of 60% of mutations followed by signature 9. According to the mutational signature profile of different diseases, both signature 9 and 17 are observed in human B cell lymphoma.To understand the genesis of the malignant transformation, we scarified Tg,CD19Cre+/-,APEX2+/- mice and control Tg,CD19Cre+/- mouse at 25 weeks after birth to see the pre-malignant changes in lymphoid organs. We observed enlarged and increased follicle numbers in lymph nodes and in spleen in Tg,CD19Cre+/-,APEX2+/- mice compared to control. A single cell sequencing is underway to detect clonal changes at an early stage.Our results demonstrate a single DNA-repair related gene responsible for inducing genomic instability with malignant transformation providing a model to study oncogenesis as well as possible preventative measures. DisclosuresAnderson:Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees; C4 Therapeutics: Other: scientific founder; Gilead Sciences: Membership on an entity's Board of Directors or advisory committees; Oncopep: Other: scientific founder; MedImmune: Membership on an entity's Board of Directors or advisory committees; Millenium Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees.

Половые различия морфофункциональных изменений иммунной системы у крыс Вистар разных возрастных групп при экспериментальной эндотоксинемии

Objective. The aim was revealing gender differences in morphological and functional changes of lymphoid organs (thymus and spleen), changes of cytokine production and subpopulation composition of peripheral blood lymphocytes in Wistar rats of three age groups with endotoxemia. Materials and methods. We used male and female Wistar rats of three age groups: newborns, prepubertal and sexually mature adult rats. A day after the injection of 15 mg/kg of O26:B6 E. coli lipopolysaccharide (LPS), the volume fraction of the functional zones of the thymus and spleen, the number of AnnexinV + apoptotically dying cells in the thymus, the relative and absolute number of lymphocyte subpopulations (CD3+CD4+, CD3+CD8a+, CD4+CD25+Foxp3+, CD3-CD45R+) in peripheral blood and ex vivo production of IL-2, IL-4, IFN-γ and TNF-α were estimated. Results. Sex differences in the response of the immune system after the LPS injection in different age periods are expressed differently: in the neonatal period, there is immunosuppression in females (decrease in the ex vivo production of IL-2, TNF-α and IFN-γ), and there is activation of pro-inflammatory reactions in males (increase in ex vivo production of IL-2 and TNF-α). As compared with other age periods at prepubertal age, LPS-induced immunological disorders are more pronounced, and gender differences are minimal and related only to the number of T-regulatory and B-lymphocytes. In the adults, the LPS-induced immunosuppression is most pronounced in males - they have a decrease in the production of all the cytokines studied and a decrease in the number of cytotoxic and regulatory T-lymphocytes and B-cells. Conclusion. Thus, in each of the studied age periods - newborn, prepubertal and adult, the sexual differences in the immune system reactions are expressed differently and, apparently, these differences are determined by the content of sex steroid hormones, the concentration of which varies with age.

Inflammation induced by different plasmid types of russian <i>Yersinia pseudotuberculosis</i> strains

In the 2000s, a scientific interest to the Far Eastern scarlet-like fever (FESLF) mainly recorded In Russia and Japanwas remarkably increased. Such clinical and epidemic manifestation of human pseudotuberculosis is related to a certain bacterial clonal lineage characterized by a specific plasmid profile (pVM82, pYV48), sequence type (2ST) as well as the yadA gene allele (1st allele). In our study we examined features of inflammatory changes characterizing plasmidassociated pathogenicity of the FESLF pathogen. In addition, organ histopathology in experimental animals infected intraperitoneally with Y. pseudotuberculosis strains of the four plasmid types 48+:82+; 48+:82-; 48-:82+; 48-:82-; and 48-:82- was investigated. It was found that the mortality rate in animals infected with Y. pseudotuberculosis H-5015 strain (82+:48+) bearing two plasmids with a molecular weight of 82 and 48 MDa was 40%. A picture of diffuse pneumonia with moderate inflammatory infiltration in pulmonary tissue and changes in lymphoid organs characterizing immunodeficiency we observed as early as 3 days postinfection (p.i.). On the contrary, animals infected with Y. pseudotuberculosis H-5015 strain (82+:48) bearing a single plasmid 82 MDa pVM, mortality rate was 30%. A vascular reaction in the lungs and liver as well as deteriorated vascular destructive changes were revealed starting from day 3 and on day 57 days p.i., respectively, which was paralleled with perivascular infiltration mainly by mononuclear cells and focal pneumonia as well as a reaction of bronchialassociated lymphoid tissue and minimal organ destructive changes. On day 7 p.i., signs of granulomatous inflammation in the liver in a form of small mononuclear cell clusters and perivascular compact infiltrates were found. At all time points, lymphoid organ hyperplasia was noted. In case the infection caused by H-5013 strain (48+), the mortality rate was 80%. Inflammatory changes with dominant mononuclear cells were detected as early as 1 day p.i. associated with a picture of large focal bronchopneumonia, more pronounced in the non-survivor animals, also demonstrating signs of severe immunosuppression in the lymphoid organs. Starting from day 3 p.i., lymphoid hypoplasia in the spleen and lymph nodes was detected in all infected animals paralleled with pathogen-associated tissue damage in various organs. Animals infected with the plasmid-free H-5013 strain 48-) resulted in 25% mortality rate. Moreover, starting from day 3 p.i., a slight mononuclear inflammatory infiltration in the lungs and liver, a moderate giant cell reaction in the splenic pulp, and loose perinodal inflammatory infiltration in the lymph nodes were observed. Thus, while modeling infection caused by different plasmid types of Y. pseudotuberculosis, the data on differences in histopathology of changes in diverse organs regarding dynamics and generalization of the inflammatory response, as well as the severity of pathogen-associated damage in the lymphoid tissue were obtained. In case Y. pseudotuberculosis strains contained pVM82 plasmid with or without virulence plasmid pYV vs. single pYV-positive strains, an area of the inflammatory response as well as severity of immunosuppression manifested by splenic and lymph node delymphatization were decreased. It allowed to suggest that pVM82 plasmid found In Russia-originating Y. pseudotuberculosis strains might be implicated in limiting intensity of inflammatory response, bacterial dissemination and severity of lymphoid organ damage.

Morphological Characteristics of the Thymus and Spleen and the Subpopulation Composition of Lymphocytes in Peripheral Blood during Systemic Inflammatory Response in Male Rats with Different Resistance to Hypoxia.

On the model of the systemic inflammatory response (SIRS), induced by lipopolysaccharide (LPS), the morphological and functional changes in the thymus and spleen and the subpopulation composition of peripheral blood lymphocytes of rats differing in resistance to hypoxia were studied. It was demonstrated that the level of endotoxin in blood serum after 3 hours of LPS administration in susceptible-to-hypoxia rats was 64 times higher than in the control group, while in tolerant-to-hypoxia animals it was only 8 times higher in 6 hours. After 24 hours of LPS injection, only in susceptible-to-hypoxia rats did the level of C-reactive protein in blood serum increase. There is a difference in the dynamics of morphological changes of lymphoid organs after LPS injection in tolerant- and susceptible-to-hypoxia animals. After 3 hours of LPS administration, the tolerant-to-hypoxia rats showed no changes in the thymus, spleen, and subpopulation composition of lymphocytes in peripheral blood. After 6 hours there was only a decrease in B-lymphocytes and increase in cytotoxic T-lymphocytes and NK cells. After 1 day of LPS injection, the tolerant-to-hypoxia rats had devastation in PALS of the spleen. After 3 hours of LPS injection the susceptible-to-hypoxia animals had reactive changes in the lymphoid organs: decrease of the thymus cortex, narrowing of the marginal zones of spleen lymphoid follicles, widening of their germinal centers, and a decrease in the absolute number of cytotoxic T-lymphocytes, NK cells, and B-lymphocytes. After 24 hours of LPS injection the tolerant-to-hypoxia animals had a greater absolute number of T-lymphocytes and NK cells in comparison with the susceptible rats. Thus, in animals with different resistance to hypoxia the LPS-induced SIRS is characterized by different dynamics of morphological and functional changes of the thymus and spleen. The obtained data will serve as a basis for the development of new individual approaches to the prevention and treatment of infectious and inflammatory diseases.

GENERAL AND SPECIFIC STRUCTURAL CHANGES OF LYMPHOID ORGANS IN THE HIGH DOSE APPLICATION OF SODIUM SELENITE

PURPOSE: to evaluate experimentally the features of structural and functional changes in lymphoid organs under the conditions of oral administration of high doses of sodium selenite and after its termination. MATERIAL AND METHODS. The study was conducted on 30 sexually mature male Wistar rats, weighing 200-220 g. The morphometric research of the thymus, group lymphoid nodules, mesenteric lymph nodes, spleen, and laboratory investigation of blood were performed. The animals were divided into 3 groups depending on the nature of the study. The first (control) group consisted of intact rats. Animals of groups 2 and 3 were orally administered sodium selenite, at a rate of 5 mg/kg of mass for 5 days. Morphofunctional studies of lymphoid organs in group 2 were performed on day 6, in group 3 – on day 14. RESULTS. The degree of severity and directional effect of structural and changes are determined by the functional specialization of the studied organs. CONCLUSION. Signs of endotoxicosis indicate evident structural and functional changes in the lymphoid organs after five times administration of sodium selenite. Canceling the administration helps to improve the organism's reserve capacity and adapt to altered metabolic processes.

Immunosenescence-like state is accelerated by constant light exposure and counteracted by melatonin or turmeric administration through DJ-1/Nrf2 and P53/Bax pathways

The awareness of the interrelationship between immunosenescence and constant light exposure can provide new insights into the consequences of excessive exposure to light at night due to light pollution or shift work. Here, we investigated whether constant light exposure (LL) acts as an inducer of immunosenescence. We also determined the role of melatonin or turmeric in reversing the putative effects of constant light and explored for the first time the underlying molecular mechanisms. Young (3–4-month-old) rats were exposed daily to LL alone or in combination with each of melatonin and turmeric for 12 weeks. A group of aged rats (18-months old; n = 6) was used as a reference for natural immunosenescence. Constant light exposure resulted in remarkable pathophysiological alterations resembling those noticed in normal aged rats, manifested as apparent decreases in antioxidant activities as well as Nrf2 and DJ-1 expressions, striking augmentation in oxidative stress, proinflammatory cytokines and expression of TNFα, Bax, and p53 genes, and deleterious changes of lymphoid organs, Co-administration of melatonin or turmeric was able to reverse all alterations induced by LL through upregulation of Nrf2/DJ-1 and downregulation of p53/Bax pathways. These data suggest that LL accelerates immunosenescence via oxidative stress and apoptotic pathways. They also demonstrate for the first time that turmeric is comparable to melatonin in boosting the immune function and counteracting the LL-associated immunosenescence. These effects suggest that turmeric supplementation can be used as an inexpensive intervention to prevent circadian disruption-related immunosenescence. However, to validate the effects of turmeric on humans further studies are warranted.

Ameliorative efficacy of citrus oil in aflatoxin induced changes in lymphoid organs in broilers-A pathomorphological evaluation

A total of 160 day-old broiler chicks were divided randomly into four groups with two replicates of 20 birds each. The birds were fed with basal diet, basal diet with CFO, basal diet with aflatoxin, basal diet with CFO and AF. Serum globulin level was significantly reduced in birds fed with AF only on 14th day of treatment. Microscopically, mild degree of congestion, histiocytosis and cellular sparcity of the periarteriolar lymphoid component were observed in the spleen whereas lymphoid cell depletion in thymus and bursal follicles were prominent. Additionally, thymus revealed moderate degree of congestion and haemorrhages in widened medulla, histiocytosis and degeneration of Hassall’s corpuscles. In CFO and AF fed birds, the extent and degree of lesions were lesser with compact arrangement of lymphoid cell with widening of cortex was observed mainly during later days of experiment. There was widening of lymphoid component of caecal tonsils up to mucosal layer in CFO fed birds.

Evaluation of pathological changes of natural infectious bursal disease virus infection in the lymphoid organs of Black Harco pullets

This study examined the sequential pathological changes in the lymphoid organs (bursa of Fabricius, thymus, spleen and caecal tonsils) of 7-week-old Harco pullet chicks that showed severe clinical disease and lesions during a natural infection with a virulent infectious bursal disease virus. Clinical signs were sleepiness, droopy appearance, greenish-whitish diarrhoea, anorexia and prostration followed by death. Mortality rate was 78% within 3 days of the infection followed by recovery. Gross lesions were marked haemorrhages in the pectoral and thigh muscles, mucosa of the proventriculus and gizzard junction, and caecal tonsils. Bursa of Fabricius, thymus, spleen and kidneys were initially enlarged; however, bursa of Fabricius and thymus were later atrophic. Histologic lesions showed marked oedema, infiltration of heterophils, hyperaemia, and lymphoid depletion and hyperplastic corticomedullary layer in the bursa of Fabricius, lymphoid necrosis in thymus, spleen, and caecal tonsils. Lymphocytic depletion was marked in the bursa of Fabricius as early as day 1 of the infection, and in the spleen, thymus and caecal tonsils on day 2 of the infection. However, there were fibroplasias in the bursa of Fabricius and thymus but repopulation of lymphocytes in the spleen and caecal tonsils of birds sacrificed on day 6 of the infection. Confirmation of IBD was carried out using agar gel immunodiffusion test. The above observations showed that marked depletion of lymphocytes in the lymphoid organs correlated with marked clinical IBD while repopulation of lymphocytes in the spleen and caecal tonsils correlated with the recovery phase in pullet chicks. The description of the pathological changes in lymphoid organs caused by the IBDV currently circulating in Nigeria will be useful in assessing the time and recognition of early diagnostic features of the disease. Keywords: Infectious bursal disease, Lymphoid organs, Pathology, Pullets

Evaluation of the utility of popliteal lymph node examination in a cyclophosphamide model of immunotoxicity in the rat

The objective of this study was to characterize the variability of rat lymphoid organ weights and morphology following treatment with a known immunotoxicant, with a focus on the usefulness of evaluating popliteal lymph node weight and histology. Cyclophosphamide was administered to male Sprague-Dawley rats by oral gavage at doses of 2, 7 or 12 mg/kg/day for 10 consecutive days. Left and right popliteal lymph nodes (PLN), spleen and thymus were collected at necropsy, weighed, fixed and processed for histopathology. Femoral bone marrow was also collected, fixed and processed for histology. Organ weight variability was greater for PLN than for either spleen or thymus in control animals. There was a significant but weak correlation between paired left and right PLN weights (p < 0.005; r2 = 0.2774). Significant treatment-related decreases in lymphoid organ weights were observed in spleen and thymus at ≥ 7 mg/kg/day (p < 0.01), whereas in PLN a significant decrease (p < 0.05) was noted only at 12 mg/kg/day. The inclusion of PLN did not enhance the sensitivity of detection of systemic treatment-related changes in lymphoid organs in a rat cyclophosphamide model.

Alterations of morphology of lymphoid organs and peripheral blood indicators under the influence of gold nanoparticles in rats

At present, gold nanoparticles (GNPs) are widely used in biomedical applications such as cancer diagnostics and therapy. Accordingly, the potential toxicity hazards of these nanomaterials and human safety concerns are gaining significant attention. Here, we report the effects of prolonged peroral administration of GNPs with different sizes (2, 15 and 50[Formula: see text]nm) on morphological changes in lymphoid organs and indicators of peripheral blood of laboratory animals. The experiment was conducted on 24 white mongrel male rats weighing 180–220[Formula: see text]g, gold nanospheres sizes 2, 15 and 50[Formula: see text]nm were administered orally for 15 days at a dosage of 190[Formula: see text][Formula: see text]g/kg of animal body weight. The GNPs were conjugated with polyethylene glycol to increase their biocompatibility and bioavailability. The size-dependent decrease of the number of neutrophils and lymphocytes was noted in the study of peripheral blood, especially pronounced after administration of GNPs with size of 50[Formula: see text]nm. The stimulation of myelocytic germ of hematopoiesis was recorded at morphological study of the bone marrow. The signs of strengthening of the processes of differentiation and maturation of cellular elements were found in lymph nodes, which were showed as the increasing number of immunoblasts and large lymphocytes. The quantitative changes of cellular component morphology of lymphoid organs due to activation of migration, proliferation and differentiation of immune cells indicate the presence of immunostimulation effect of GNPs.

Tissue distribution of B-lymphocyte subsets (IgA, IgG and IgM) in the mucosa and lymphoid tissues of broilers immunized with Gumboro vaccine

The present research was designed to study the histological and immunohistochemical changes of lymphoid organs (bursa of Fabricius and cecal tonsil) and in the ileum (representative mucosal organ) of broiler chickens after immunization with Gumboro vaccine. Two groups (n=24) of Cobb-500 broiler chickens were reared in a same environment A mild vaccine (BUR® 706) followed by a intermediate (Nobilis® Gumboro 228 E) type vaccine was administered for immunization of chickens and samples were collected at 7 days interval for up to 32 days of age. The conventional histological structure of all three organs of the present study was similar to the earlier reports. In addition, in the bursa of Fabricius, the population of lymphocytes and the size of the follicles were found to increase in vaccinated chickens than the control chickens. The Igs positive cells (IgA, IgG and IgM) were distributed principally beneath the capsule, around the follicles and in the cortex and medulla. The frequencies of IgG- and IgM- positive cells were more than the IgA-positive cells in the bursa of vaccinated group. IgM-positive cells became peak at day 25 and started to decline at day 32 in the bursa of Fabricius of vaccinated groups of chickens. In the cecal tonsils and ileum, the Igs positive cells (IgA, IgG and IgM) distributed around the intestinal gland and within the lymphatic nodules of the lamina propria, in the core of the villi, and within the epithelium in both the control and vaccinated chickens. Their frequency per 0.1 mm2 area of the lamina propria and in the epithelium was increased abruptly in the vaccinated group than the control broiler chickens. Like bursa, in the cecal tonsil and ileum of vaccinated chickens, the frequencies of IgG- and IgM-positive cells were also more than IgA-positive cells. The present study suggested that, the Igs positive cells were greatly accelerated in the vaccinated chickens than the control chickens and it may be due to immunomodulatory effect of vaccine.DOI: http://dx.doi.org/10.3329/bjvm.v11i1.14154Bangl. J. Vet. Med. (2013). 11 (1): 13-19

In vivo effects of microcystins and complex cyanobacterial biomass on rats (Rattus norvegicus var. alba): Changes in immunological and haematological parameters

Toxic cyanobacteria represent a serious health and ecological problem in drinking and recreational waters worldwide. Some previous toxicological studies investigated effects of isolated microcystins on laboratory rodents including mice and rats. However, much less attention has been paid to more realistic exposure situations such as the effects of MCs accumulated in food. The objectives of the present study were to provide a simple model simulation of the food chain in order to evaluate impacts of microcystins (MCs) on rat immune and haematologicalparameters. Impacts of feeding experimental rats with a diet containing fish meat with and without microcystins and complex toxic biomass have been studied during a 28 day exposure. Red blood cell parameters (RBC counts, haematocrit values, MCH, MCV and MCHC) showed significant differences in experimental groups (p ≤ 0.05, p ≤ 0.01) in comparison with the control group. We also detected an immunomodulatory effect in the experimental groups. NK cells and γδ+ T lymphocytes were significantly increased in peripheral blood in the group exposed to isolated microcystin in the food. Significant change in the ratio of CD4+ and CD8+ cells (increase of CD4+ and a drop in CD8+) was found in the group with added cyanobacterial biomass with low concentration of MCs. The greatest changes in lymphoid organs were observed in the same groups. There was an increase of spleen subpopulations of γδ+ T lymphocytes as well as of IgM+ lymphocytes (B lymphocytes) and CD8+ T lymphocytes. Indeed, the modulation of CD4+ and CD8+ of peripheral lymphocytes was associated with similar changes in thymic lymphocytic subpopulations. In summary, food containing fish meat with considerable doses of microcystins (or toxic cyanobacterial biomass) induces significant changes in RBC parameters and influence preferably innate part of the immune system represented by NK cells and by gamma-delta T cells, which are known to play role as a bridge between adaptive and innate immune response.

Hyperlipidemia offers protection against Leishmania donovani infection: role of membrane cholesterol

Leishmania donovani (LD), the causative agent of visceral leishmaniasis (VL), extracts membrane cholesterol from macrophages and disrupts lipid rafts, leading to their inability to stimulate T cells. Restoration of membrane cholesterol by liposomal delivery corrects the above defects and offers protection in infected hamsters. To reinforce further the protective role of cholesterol in VL, mice were either provided a high-cholesterol (atherogenic) diet or underwent statin treatment. Subsequent LD infection showed that an atherogenic diet is associated with protection, whereas hypocholesterolemia due to statin treatment confers susceptibility to the infection. This observation was validated in apolipoprotein E knockout mice (AE) mice that displayed intrinsic hypercholesterolemia with hepatic granuloma, production of host-protective cytokines, and expansion of antileishmanial CD8(+)IFN- γ (+) and CD8(+)IFN- γ (+)TNF- α (+) T cells in contrast to the wild-type C57BL/6 (BL/6) mice when infected with LD. Normal macrophages from AE mice (N-AE-MΦ) showed 3-fold higher membrane cholesterol coupled with increased fluorescence anisotropy (FA) compared with wild-type macrophage (N-BL/6-MΦ). Characterization of in vitro LD-infected AE macrophage (LD-AE-MΦ) revealed intact raft architecture and ability to stimulate T cells, which were compromised in LD-BL/6-MΦ. This study clearly indicates that hypercholesterolemia, induced intrinsically or extrinsically, can control the pathogenesis of VL by modulating immune repertoire in favor of the host.

Immunohistochemical characterization of selected cell markers for the detection of hematopoietic cells in formalin-fixed, paraffin wax-embedded lymphoid tissues of harbor seals ( Phoca vitulina) and walruses ( Odobenus rosmarus rosmarus)

To facilitate a detailed investigation of pinniped lymphoid organs, 30 monoclonal antibodies (mAb) as well as eight polyclonal antibodies (pAb) of different species specificities directed against cell antigens of the hematopoietic system were tested for immunohistochemical cross-reactivity on formalin-fixed, paraffin wax-embedded tissues of harbor seals ( Phoca vitulina) and a walrus ( Odobenus rosmarus rosmarus). Six monoclonal and eight polyclonal antibodies showed specific immunoreactivities. Lymphocytes were immunolabeled by an anti-CD3 pAb, anti-Foxp3 mAb and anti-CD79α mAb, while plasma cell subpopulations were recognized by anti-IgA pAb, anti-IgG pAb and anti-IgM pAb as well as by anti-kappa- and anti-lambda light chain pAb. Cells of the histiocytic lineage were recognized by lysozyme-, myeloid/histiocyte antigen-, and CD68-specific markers. Furthermore, dendritic cell-like cells were detected by an anti-S100 protein pAb. The MHC class II antigen was labeled on the majority of immune cells of the harbor seal and walrus using a bovine mAb. Mast cells were stained by an anti-mast cell tryptase mAb. Thus, using these antibodies from various species, it is now possible to determine phenotypical changes in lymphoid organs and detect different leukocyte subsets involved in inflammatory responses in archived tissue samples of these pinniped species.