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At least 937 records · Page 52Linked to original sources
PubMed1999

Further characterization of M cells in gut-associated lymphoid tissues of the chicken.

M cells are considered to be the most effective cells for the transport of antigens from the intestinal lumen into the gut-associated lymphoid tissue. M cells are characterized by their ultrastructural appearance, the selective uptake of antigens, the binding of lectins, and the presence of underlying lymphocytes. Little attention has been paid to the interaction of intra-epithelial leucocytes and M cells in chickens; therefore, we have investigated both cell types separately and using double immunocytochemical staining in cecal tonsils and Meckel's diverticulum. In the follicle-associated epithelium (FAE), cells were present that differ from their neighbors by short, irregular microvilli. Ferritin was absorbed by these putative M cells, but also by other epithelial cells. The lectins of Triticum vulgaris (WGA) and Glycine max (SBA) showed a patchy staining of the FAE. The numbers of intra-epithelial leucocytes (IEL) increased rapidly after hatch, reaching innumerable at 6 wk of age. Most IEL were T lymphocytes expressing CD8 and only about 30% of them were B lymphocytes. Nevertheless, double staining of M cells (WGA/SBA) and IEL showed that M cells were much fewer than IEL. These results indicate that M cells are not solely induced by the intra-epithelial localization of leucocytes. Because the phenotype of IEL reflected the content of the adjacent underlying lamina propria, IEL immigrate the FAE locally and do not migrate along with the epithelial cells from the crypts. In conclusion, M cells exist in the chicken, but their phenotype and function are less well demarcated from neighbor epithelial cells than is seen in mammals.

Animals↗
PubMed2004

Depletion of CD4 T lymphocytes in human lymphoid tissue infected ex vivo with doxycycline-dependent HIV-1.

We investigated whether CD4+ T cells that do not produce HIV-1 are killed in HIV-infected human lymphoid tissue. Tissue blocks were inoculated with high amount of doxycycline-dependent HIV-rtTA. Doxycycline triggered productive infection and loss of CD4+ T cells in these tissues, whereas without doxycycline, neither productive infection nor CD4+ T cell depletion was detected in spite of the massive presence of virions in the tissue and of viral DNA in the cells. Thus, HIV-1 alone is sufficient to deplete productively infected CD4+ T cells but is not sufficient to cause the death of uninfected or latently infected CD4+ T cells.

Anti-Infective Agents↗
PubMed1994

Distribution of equid herpesvirus-1 (EHV-1) in respiratory tract associated lymphoid tissue: implications for cellular immunity.

Twelve adult ponies and 2 conventional foals were exposed intranasally to EHV-1, strain Ab4 (TCID50 10(-6.6) and samples of respiratory tract associated lymphoid tissues were recovered between 12 h and 13 days after infection. Infectious virus was detected in tissue homogenates using susceptible cell monolayers and expression of viral antigens was monitored using indirect immunoperoxidase histochemistry on paraffin sections. The results showed both infectious EHV-1 and viral antigens in respiratory tract associated lymph nodes 12 h after exposure. Infected leucocytes were identified morphologically as lymphocytes, monocytes, macrophages and plasma cells. The rapid intracellular localisation of EHV-1 in lymph nodes implies that cell mediated immunity is an important aspect of the equine response to this virus.

Animals↗
PubMed1984

Morphometry of normal human lymphoid tissues. Nuclear parameters for comparative studies of lymphoma.

Prior to performing morphometric studies of non-Hodgkin's lymphoma, baseline nuclear parameters of the various compartments of normal human lymphoid tissue are needed. Such information was obtained from traced nuclear profiles from a series of human lymph node biopsy specimens and samples of tonsil and spleen. All tissues showed reactive hyperplasia. In combined samples of adult lymph node specimens, nuclear parameters of mantle and paracortical lymphocytes were similar, but were smaller and more regular than small, unstimulated germinal center lymphocytes. Despite variation in mean nuclear size between various lymph node samples, transformed lymphocytes in germinal centers had a constant relationship to the nuclei of small untransformed lymphocytes in these regions. Our results indicate that there is considerable variation in the nuclear parameters of lymphocytes within a specific region of the normal lymph node of each case, but that such differences are difficult to appreciate in histologic preparations.

Adolescent↗
PubMed1995

Induction of IgA and IgG antibodies in vaginal fluid, serum and saliva following immunization of genital and gut associated lymphoid tissue.

Vaginal immunization with the Simian immunodeficiency virus (SIV) was investigated in macaques in order to study genital mucosal antibodies. A combined route of genital- and gut-associated lymphoid tissues was used to stimulate IgA and IgG antibodies in vaginal fluid, serum and saliva. Macaques were immunized with a recombinant, particulate SIV antigen (SIV gag P27), covalently linked to the mucosal adjuvant cholera toxin B subunit (CTB). The animals were immunized sequentially as follows: vaginal (x2) followed by oral (x3), or the reverse sequence of immunization. The results show that both vaginal followed by oral immunization or the reverse sequence induces specific p27 IgA and IgG antibodies in the vaginal fluid and serum. IgA antibodies were also detected in saliva. Vaginal IgA antibodies have the secretory component and J chain suggesting that they are of secretory origin.

Adjuvants, Immunologic↗
PubMed2005

Evolution of nef variants in gut associated lymphoid tissue of rhesus macaques during primary simian immunodeficiency virus infection.

We utilized the simian immunodeficiency virus model of AIDS to examine evolution of nef gene in gut-associated lymphoid tissue (GALT) during primary and early asymptomatic stages of infection. Macaques were infected with a cloned virus, SIVmac239/nef-stop harboring a premature stop codon in the nef gene. Restoration of the nef open reading frame occurred in GALT early at 3 days post-infection. Analysis of nef sequences by phylogenetic tools showed that evolution of nef was neutral thereafter, as evidenced by the ratio of synonymous to nonsynonymous substitutions, a star pattern in unrooted trees and distribution of amino acid replacements fitting a simple Poisson process. Two regions encoding for a nuclear localization signal and a CTL epitope were conserved. Thus, GALT was a site for strong positive selection of functional nef during initial stages of infection. However, evolution of the nef gene thereafter was neutral during early asymptomatic stage of infection.

Amino Acid Substitution↗
PubMed2000

Isolation and purification of lymphocyte subsets from gut-associated lymphoid tissue in neonatal swine.

The characterization of lymphoid subsets isolated from different anatomical sites is of great importance for understanding the mechanisms and interactions of normal and pathological immune reactions in the pig. The objective of this study was to standardize a protocol for the isolation of lymphocytes from mucosal tissues of neonatal pigs. Specific protocols for the isolation of lymphocytes from Peyer's patches of jejunum (jejPP) and ileum (ilPP), the Intraepithelial (IE) and lamina propria (LP) compartments of the jejunum and ileum, the mesenteric lymph nodes (MLN), and the peripheral blood (PBMC) are described in detail. The analysis of the cells isolated indicated a high viability (>90%). The histological sections from fragments collected from the intestine demonstrated that in nursing young pigs, the recovery of IE and LP lymphocytes may be limited because of the low numbers of lymphocytes present in early age. In addition, the presence of large intracytoplasmic vacuoles and hyaline droplets between the columnar epithelial cells during the first week of age interferes with the isolation of pure lymphocytes from the IE and LP compartments. Optimal lymphocyte yields for all the samples analyzed was confirmed by immunostaining with the pan-lymphocyte marker, CD45. The successful isolation and comparison of large numbers of pure populations from compartmentalized areas of the intestine and associated lymphoid tissues opens up a broad area for the investigation of mucosal immune responses of pigs.

Animals↗
PubMed1989

Antigen delivery to gut associated lymphoid tissue of rabbits.

A rabbit model was developed so that antigens, microbes or potential mucosal vaccines could be delivered in multiple doses directly to the luminal surface of the gut associated lymphoid tissue (GALT) located in the cecal appendix. A polyethylene catheter was implanted surgically into the tip of the appendix. It exited the body wall and progressed subcutaneously around the thorax to the dorsocervical region where it was attached to a subcutaneous obturator. The catheters were flushed every day with sterile saline. To assess patency of the system, radiographic contrast media was injected and the animals were radiographed. Rabbits were necropsied at 10, 30 and 60 days and tissues evaluated by histological, immunohistochemical and electron microscopic means. The microbial flora was evaluated also. All tissues examined were free of significant abnormalities. The advantage of this delivery system is its ability to provide multiple doses of immunogenic agents directly to a physiologically normal appendix over an extended period.

Animals↗
PubMed1997

The t(11;18)(q21;q21) chromosome translocation is a frequent and specific aberration in low-grade but not high-grade malignant non-Hodgkin's lymphomas of the mucosa-associated lymphoid tissue (MALT-) type.

Primary extranodal malignant non-Hodgkin's lymphoma arising from the mucosa-associated lymphoid tissue (MALT-type lymphoma) represents a subtype of B-cell lymphoid malignancies with distinct clinicopathological features and is often associated with a favorable prognosis. Unlike the situation in nodal non-Hodgkin's lymphoma of B-cell lineage, few data are still available concerning the chromosomal constitution of MALT-type lymphomas. Until now, cytogenetic data from 29 low-grade MALT lymphomas with karyotypic alterations have been reported from different institutions, and virtually no data were available for high-grade MALT-type lymphomas. We have analyzed the cytogenetics of 44 MALT lymphomas arising in the stomach, parotid gland, thyroid gland, lung, breast, and conjunctiva. Clonal chromosome aberrations have been detected in 13 of 20 (65%) low-grade and 20 of 24 (83%) high-grade tumors. More than half of the low-grade lymphomas with abnormal karyotypes (7 of 13 cases, 53%) displayed clonal t(11;18)(q21;q21), thus specifically associating this translocation with MALT-type lymphomas for the first time in a larger series. In contrast, t(11;18) was not found in a single case of 20 high-grade MALT-type lymphomas with abnormal karyotypes, nor were translocations t(14;18) or t(3;14), characterizing about 10-35% of primary nodal large cell lymphomas. Instead, these lymphomas were associated with t(8;14)(q24;q32) in three cases, frequent deletions in the long arm of chromosome 6, and partial or whole gains of chromosomes 3, 7, 17, 18, and 21.

Chromosome Aberrations↗
PubMed1981

The localization of populations of lymphocytes defined by monoclonal antibodies in rat lymphoid tissues.

The localisation of subpopulations of T lymphocytes as defined by the monoclonal antibodies W3/25 and MRC OX 8 was determined by an indirect immunoperoxidase technique on cryostat sections of rat lymphoid tissues. Both subpopulations were present throughout T-dependent areas with only scattered T cells, largely W3/25 positive, in the B areas. The W3/25 antigen was also found on macrophages in the medulla of lymph nodes and in the peritoneal cavity and liver.

Animals↗
PubMed2000

Normalization of immune activation in lymphoid tissue following highly active antiretroviral therapy.

Although significant progress has been made in understanding immune reconstitution in peripheral blood following highly active antiretroviral therapy (HAART), less is known about immune changes in lymphoid tissue. Here, the expression of cytokine proteins (interferon gamma [IFN-gamma], interleukin [IL]-2, IL-4, IL-10, IL-1alpha, and IL-1beta) and surface antigens (CD4, CD8, CD1a, CD68) as well as cellular proviral HIV-1 DNA were determined in sequential tonsil biopsies before and at 4, 12, and 48 to 56 weeks posttherapy by quantitative in situ image analysis and fluorescent in situ 5;-nuclease assay (FISNA). Despite plasma virus suppression, a fraction of tonsil cells harbored pro-viral DNA for up to 1 year. A fourfold to eightfold increase in CD8+ T cells in tissue compared with seronegative controls and an increased frequency of CD1a+ dendritic cells prior to HAART reached control levels at week 56. The frequency of IFN-gamma expressing cells was 10-to 15-fold higher than controls before therapy and was comparable with findings in seronegative controls by week 56. Elevated baseline expression of IL-1alpha and IL-1beta was reduced by week 4 but IL-1alpha levels remained elevated in 1 of 3 patients at week 56. These findings suggest that with effective viral suppression the immune system in tissue may return to a more resting state.

Antiretroviral Therapy, Highly Active↗
PubMed1993

Low-grade B-cell lymphoma of mucosa-associated lymphoid tissue arising in the kidney.

We describe a malignant lymphoma arising in the kidney that exhibited clinical and histologic features of low-grade B-cell lymphoma of mucosa-associated lymphoid tissue (MALT). Clinically, the neoplasm involved the kidney and one perirenal lymph node (stage IIE) and did not recur or disseminate following nephrectomy, lymphadenectomy, and local radiation therapy. Histologically, the neoplasm recapitulated the features of low-grade B-cell lymphomas of MALT at other sites. The neoplastic cells resembled centrocyte-like cells, some of which formed lymphoepithelial lesions with renal tubules, and reactive lymphoid follicles were scattered within the neoplasm. The neoplastic cells expressed monotypic cytoplasmic Ig kappa. Low-grade B-cell MALT lymphomas arising in the kidney are rare. Their occurrence further demonstrates the diversity of anatomical sites that may be involved by MALT lymphomas. In addition, this neoplasm also had histologic and cytologic features resembling those of monocytoid B-cell lymphoma, supporting the hypothesis that low-grade B-cell lymphomas of MALT and monocytoid B-cell lymphomas are closely related and may be two morphological manifestations of the same neoplasm.

Aged↗
PubMedDate not supplied

Effects of Newcastle disease vaccines and Newcastle disease/infectious bronchitis combination vaccines on the head-associated lymphoid tissues of the chicken.

Ten Newcastle disease virus (NDV) and 10 NDV and infectious bronchitis virus (IBV) combination vaccines (NDV/IBV) were evaluated for their effect on the head-associated lymphoid tissue (HALT) of 2-wk-old chicks. After vaccination, the chicks were subjected to an in vivo assay that measures the ability of the gland of Harder (GH) to respond to killed Brucella abortus antigen given in the eye by titering B. abortus antibodies in the tears. Following this, several sites in the HALT and trachea were examined histologically and scored for microscopic changes. The results indicated that three of the NDV/IBV combination vaccines (one BI/Mass&Conn and two LaSota/Mass&Conn) interfered with the GH response to killed B. abortus, whereas none of the NDV vaccines did Histologically, several changes were noted in the vaccinated chicks; however, no changes in the GH were observed that could explain microscopically the GH depression. With the IBV-only vaccines reported earlier (16), and the NDV-only and NDV/IBV combination vaccines reported here, a total of 36 vaccines have been evaluated using the same testing protocol. The conclusions of these combined studies suggest that several of the modified live virus vaccines containing IBV, either alone or in combination with NDV, interfere with the ability of the GH/HALT to respond to antigenic stimulation.

Animals↗
PubMed1999

Glycoconjugate expression in follicle-associated epithelium (FAE) covering the nasal-associated lymphoid tissue (NALT) in specific pathogen-free and conventional rats.

We examined lectin-histochemically the glycoconjugate expression in the follicle-associated epithelium (FAE) covering the nasal-associated lymphoid tissue (NALT) in the rat under specific pathogen-free (SPF) and conventional (CV) conditions and compared the results for SPF and CV rats as well as for membranous (M) cells and adjacent ciliated respiratory epithelial (CRE) cells in FAE. N-acetylgalactosamine-specific lectins, Dolichos biflorus (DBA), Helix pomatia (HPA), Glycine max (SBA) and Vicia villosa (VVA), and alpha-L-fucose-specific lectin, Ulex europaeus (UEA-I), preferentially bound to M cells mainly in the luminal surface compared with CRE cells in SPF rats, whereas DBA and UEA-I showed signs of preferential binding to the apical and basolateral cytoplasm as well as to the luminal surface of M cells in CV rats. In addition, HPA, SBA and VVA more frequently and extensively labeled M cells than CRE cells in CV rats with the same subcellular staining pattern as DBA and UEA-I. On the whole, the changes in lectin binding frequency and strength were more prominent in M cells than in CRE cells in both SPF and CV rats. The present results indicate that DBA and UEA-I are useful as markers of M cells in NALT. Furthermore, the pattern of expression of carbohydrate residues recognized by such lectins in SPF and CV rats suggests that M cells are highly sensitive to environmental changes.

Animals↗
PubMed1997

[Histological examination of lymphoid follicles in conjunctiva-associated lymphoid tissue in guinea pigs--Report 1. Histological characteristics of follicular dendritic cells].

We histologically examined the existence of follicular dendritic cells (FDCs) in the follicular area of conjunctiva-associated lymphoid tissue (CALT). Animals used in the experiment were Hartley guinea pigs sensitized with a topical application to the eyes of an emulsion of a mixture of ovalbumin and Freund's complete adjuvant in equal amounts. The animals were divided into 4 groups: a group with no eye drops administered (Group A), a group examined 1 week after administration of eye-drops (Group B-1), a group examined 2 weeks after administration (Group B-2), and a group given booster administration of eye-drops (Group C). These animals were examined by methyl green pyronine staining, alpha-naphthylacetate esterase staining, and enzyme-antibody methods against S-100 protein or major histocompatibility complex class II (MHC class II) antigen. Also peroxidase-anti-peroxidase (PAP) was applied to the eyes and the uptake of PAP in CALT was observed histologically. In each group, positive reticular stains to alpha-naphthyl-acetate esterase staining and S-100 protein were found in the CALT follicular area. The positive cells were found to be dendrite cells by immunoelectron microscopy. An uptake of PAP was seen in the CALT follicular area, suggesting the function of trapping and holding the antigen-antibody complex by FDCs. It was concluded that dendritic cells present in the follicular area of CALT were FDCs.

Animals↗
PubMed2000

Distribution of T-cell subsets and immunoglobulin-containing cells in nasal-associated lymphoid tissue (NALT) of chickens.

The present study demonstrated the localization of the T-cell subsets (CD4+ and CD8+) and immunoglobulin (Ig)-containing cells (IgA, IgM, and IgG) in the nasal mucosa and its accessory structures. These lymphoid structures may be compared with nasal-associated lymphoid tissue (NALT) of rats and mice. In the chicken NALT, T-cell subsets were more widely distributed than Ig-containing cells, especially in large lymphoid accumulations restricted to the respiratory mucosa in the nasal cavity and the nasolacrimal duct. These lymphoid accumulations in the mucosa of the nasal cavity and nasolacrimal duct consisted of widely distributed CD8+ cells and deeply aggregated CD4+ cells adjacent to large germinal centers. In these lymphoid accumulations, IgG-containing cells were more frequently observed than IgM- and IgA-containing cells. T-cell subsets, predominantly CD8+ cells were more widely distributed in the duct epithelium of the lateral nasal glands than Ig-containing cells. Moreover, numerous CD8+ cells and a few Ig-containing cells were found in the chicken salivary glands, especially around the orifice of their ducts into the oral cavity. Therefore, it seems likely that the chicken NALT plays an important part in the upper respiratory tract, with a close relationship to the paraocular immune system.

Animals↗