Changes in antigen distribution and lymphocyte migration pattern after peroral immunization

The migration pattern of lymphoid cells in long-term p.o. immunized and control mice using the transfer of 51Cr-labelled cells from spleen, Peyer's patches and mesenteric or peripheral lymph nodes was studied. There are no differences between the homing activity of spleen of PLN cells to different organs of recipient animals. Peyer's patch cells from SRBC-fed mice home significantly more to the gut of antigen-fed mice; also the MLN cells from these mice exhibit a higher localization in the gut of SRBC-fed mice. There were no differences between the localization of antigen (SRBC) in different organs of SRBC-fed and control mice. The clearance of this antigen was higher in SRBC-fed animals.     

Comparison of lymphocyte production in lymphoid organs and their compartments using the metaphase-arrest technique

Summary Lymphocyte proliferation was studied in normal young anesthetized pigs by the metaphase-arrest technique using vincristine (VCR). In each animal biopsies were taken simultaneously from the thymus, mesenteric lymph nodes, spleen, palatine tonsil and Peyer's patches from the ileum and jejunum. After taking the first samples, 0.25 mg VCR/ kg body weight was injected i.v. and then four more biopsies were excised for up to 3.5 h after VCR. Imprints of the lymphoid organs were evaluated as an overall index for each organ, and histological sections were used to determine the mitotic index in typical B-and T-lymphocyte areas in these organs. In follicles of mesenteric lymph nodes, tonsils and the two types of Peyer's patches a comparable increase in the mitotic index was found, 3.62% per hour. In the corona the increase was also comparable but much lower, 0.43% per hour and in the interfollicular area similarly 0.38% per hour. In the spleen the mitotic rate was 0.69% for the white pulp and 0.42% per hour for the red pulp. In the thymic cortex the mitotic index increased by 0.49% and in the medulla by a surprisingly high value of 0.32% per hour. The metaphase-arrest technique in larger animals enables a comparison of lymphocyte production among organs and their different compartments, and demonstrates the important contribution of peripheral lymphoid organs to the renewal of the lymphocyte pools.List of Abbreviations DNA deoxyribonucleic acid - ¹⁴ C-TdR thymidine labelled with ¹⁴C - ³ H-TdR tritiated thymidine - r _m rate of entry of cells in mitosis per hour - VCR vincristine sulphate Partly presented at the XII Int. Anat. Congress in London, August 1985     

Development of the bovine ileal mucosa

The development of the bovine ileal mucosa was studied with particular reference to maturation during the fetal and neonatal period. In this region, by 4-5 months of fetal development, vacuolation of the epithelial cells had occurred on the villi, and the goblet and absorptive cells in the crypts were present. By 6-9 months, the villi were longer and more numerous than in the previous stages. At the same time, the vacuolated cells could be seen predominantly on the upper half of each villus. The absorptive cells and goblet cells were more distinct in the crypt and lower half of each villus. Moreover, the goblet cells showed differences in mucin, while in the submucosa the lymphoid follicles were seen to have enlarged to become a prominent feature of the Peyer's patches at this stage. At birth, in suckled animals, the ileal cells on the lower area of each villus and in the crypt appeared more like mature cells. In contrast, there were numerous inclusion bodies in epithelial cells on the upper half of each villus. They appeared in the apical portion of the cytoplasm as vacuoles with stainable or dense contents. By 1 week, however, epithelial cells no longer contained inclusion bodies, and absorptive and goblet cell populations had begun to emerge from the crypts. These histological results suggest that the bovine ileal mucosa has two distinct turning points during its development in the fetus and the neonate. Initially all the mucosal structures are present in fetuses at 6-7 months of gestation, and then the vacuolated cells covering the ileal villi are replaced by mature, nonpinocytosing epithelium which emerges from the crypts on or before the 7th day after birth (ileal closure).     

Expression of low levels of peripheral lymph node-associated vascular addressin in mucosal lymphoid tissues: possible relevance to the dissemination of passaged AKR lymphomas

Lymphoid tumors display a wide variety of growth patterns in vivo, from that of a solitary extralymphoid tumor, to a general involvement of all lymphoid organs. Normal lymphocytes are uniquely mobile cells continuously recirculating between blood and lymph throughout much of their life cycle. Therefore, it is reasonable to propose that disseminating malignant lymphocytes may express recirculation characteristics or homing properties consistent with that of their normal lymphoid counterparts. Trafficking of lymphocytes involves the expression and recognition of both lymphocyte homing receptors and their opposing receptors on endothelium, the vascular addressins. These cell surface elements direct the tissue-selective localization of lymphocyte subsets in vivo into organized lymphoid organs and sites of chronic inflammation where specific binding events occur between lymphocytes and the endothelium of specialized high endothelial venules (HEV). In a recent murine study of 13 lymphoma lines, we found that lymphomas that bind well to high endothelial venules, in the Stamper-Woodruff in vitro assay (an assay of lymphocyte binding to venules in frozen sections of peripheral lymph nodes or Peyer's patches), spread hematogenously to all high endothelial venule bearing lymphoid organs, whereas non-binding lymphomas did not. In some cases lymphomas that bound with a high degree of selectivity to peripheral lymph node (PLN) high endothelial venules exhibited only limited organ preference of metastasis, involving the mucosal lymphoid organs Peyer's patches (PP) in addition to the peripheral lymph nodes of adoptive recipients. Here we demonstrate that Peyer's patch high endothelial venules express a low but functional level of peripheral lymph node addressin (MECA-79) that can be recognized by lymphomas expressing the peripheral lymph node homing receptor (MEL-14 antigen).(ABSTRACT TRUNCATED AT 250 WORDS)     

Organogenesis of lymphoid tissues

The development of lymphoid organs depends on the correct expression of several molecules within a defined timeframe during ontogeny. Although this is an extremely complex process, with each secondary lymphoid tissue requiring subtly different signals, a common framework for lymphoid development is beginning to emerge. Drawing on studies of lymph nodes, Peyer's patches and nasal-associated lymphoid tissue, an integrative model of lymphoid-tissue development, involving adhesion molecules, cytokines and chemokines, which emphasizes the role of interactions between CD3-CD4+CD45+ 'inducer' cells and VCAM1+ICAM1+ stromal 'organizer' cells is presented.     

In vitro tapeworm extract-induced proliferative responses of gut-associated lymphoid cells from Hymenolepis diminuta infected mice

The development of lymphoid cells reactive to tapeworm-associated antigens during the course of Hymenolepis diminuta rejection from mice was studied using an in vitro tapeworm extract (TWE)-induced cell proliferation culture system. Mice infected with three cysticercoids on day 0 developed three adult worms by day 7 but worms were rejected by day 21 post-infection. Concomitant with worm rejection was the development of TWE-sensitized lymphoid cells which responded by proliferation when stimulated in vitro with TWE. Sensitized cells were detected in gut-associated mesenteric lymph nodes but were not detected in spleen, axillary lymph nodes, or Peyer's patches of infected mice, or in lymphoid organs of non-infected mice. These studies suggest that rejection of H. diminuta from mice is associated with the activities of gut-associated, tapeworm antigen-sensitized immune cells localized in the mesenteric lymph nodes.     

Similarity and difference of the response of Peyer's patches and mesenteric lymph nodes of rats to polychemotherapy]

The structure of the Peyer's patches and mesenteric lymph nodes of rats at different periods after polychemotherapy was investigated by light microscopy. After the use of antitumor drugs the number of the blasts and mytoses in the lymphoid follicles with the mesenteric lymph node bright centres and in the Peyer's patch follicles lowered, that along with the decrease of the size of the mantle zone in the lymph node follicles and the decrease of the area of the bright centres in the follicles of the lympoid formations in the intestinal wall was evident of the proliferation inhibition and B cells differentiation in the lymphoid organs. After the polychemotherapy the size of the germinative centres of the Payer's patch follicles decreased while the size of the mantle zone remained unchanged. The size of the mantle zone in the follicles of the mesenteric lymph nodes decreased while the size of the germinative centres did not change. The different responses of the lymphoid organs could be associated with some remote location of the lymph nodes with respect to the antigen source (damaged epithelium and intestinal lumen contents).     

The safety of a new chemical typhoid preparation containing a complex of Vi and K antigens in tests of its acute and chronic toxicity]

Acute and chronic toxicity of a new chemical typhoid preparation containing the complex of surface Vi- and K-antigens has been studied. The study has revealed that the preparation, when introduced subcutaneously and intravenously in immunizing doses in a single injection or in multiple injections, produces no toxic effect on the organs and tissues of experimental animals. In experiments of chronic toxicity the microscopic study has shown pronounced hyperplasia of the lymphoid system with enhanced macrophage reaction in the spleen, thymus, mesenteric lymph nodes and Peyer's patches in the small intestine.     

Effect of sublethal ionizing radiation on rat Peyer's patch lymphocytes

After sublethal doses of ionizing radiation, rat Peyer's patch lymphocytes regenerated significantly more slowly than lymphocytes from spleen, thymus, and peripheral lymph nodes. Long Evans rats were exposed to 150 rad (40 rad/min) of whole-body irradiation from a 60Co, gamma-emitting source. On Days 1-20 postirradiation, single cell suspensions of lymphocytes from thymus, spleen, peripheral lymph nodes, and Peyer's patches were stained with mouse monoclonal antibody reagents specific for rat lymphocyte subpopulations (Ia+ cells, non-helper T-cell subsets, and helper T-cell subsets). Cells were then counterstained with Texas Red-conjugated, goat anti-mouse IgG and, at the same time, were also stained with fluorescein diacetate to determine viable lymphocytes. The stained lymphocytes were analyzed using a dual-laser, fluorescent-activated cell sorter (Becton-Dickinson FACS-II) from which the percentage of each lymphocyte subpopulation was determined. From our studies, we found that all subpopulations of lymphocytes were affected similarly by irradiation. In addition, we observed that viable lymphocyte subpopulation in thymus, spleen, and peripheral lymph nodes from irradiated animals returned to normal (nonirradiated control animals) levels 5-12 days postirradiation, while viable lymphocyte subpopulations in Peyer's patches from irradiated animals remained suppressed up to 20 days postirradiation. These results suggest that either the lymphocytes or, more likely, the microenvironment of Peyer's patches is more greatly damaged by ionizing radiation than that observed in other lymphoid tissue.     

Absence of Peyer's patches and abnormal lymphoid architecture in chronic proliferative dermatitis (cpdm/cpdm) mice

The chronic proliferative dermatitis (cpdm) mutation causes inflammation in multiple organs, most prominently in the skin. Examination of the immune system revealed severe abnormalities in the architecture of lymphoid tissues. Peyer's patches were absent. In contrast, the spleen, lymph nodes, and nasal-associated lymphoid tissues were present. The spleen had normal numbers of T and B cells, but the spleen, lymph nodes, and nasal-associated lymphoid tissues had poorly defined follicles and lacked germinal centers and follicular dendritic cells. The marginal zone in the spleen was absent. The total concentration of serum IgG, IgA, and IgE in cpdm/cpdm mice was significantly decreased, whereas serum IgM was normal. Fecal IgA was low to undetectable in mutant mice, and the concentration of fecal IgM was increased. The titer of DNP-specific Abs following immunization with DNP-keyhole limpet hemocyanin was significantly decreased for all IgG subclasses. In contrast, T cell function appeared normal as assessed by evaluation of the contact hypersensitivity response in cpdm/cpdm mice. The cpdm mutation causes a complex phenotype that is characterized by multiorgan inflammation and the defective development of lymphoid tissues. The cpdm/cpdm mouse may be a useful model to study the factors that control the development of lymphoid tissues, in particular the Peyer's patches, and the mechanisms that control the humoral immune response.     

Morphology of germ-free piglets

The postnatal ontogeny of primary (thymus) and secondary (spleen, lymph node, lingual tonsil) lymphoid tissues was studied in germ-free colostrum-deprived piglets up to age of 68 days. The thymus, which is morphologically fully developed by the end of gestation, showed no significant differences in the germ-free and conventional state. In germ-free piglets, slow development of periarteriolarly organized lymph follicles occurred in the spleen up to the end of the observation period. As distinct from the conditions in the spleen of conventional animals, the presence of a large number of pyroninophilic cells was not observed in germ-free piglets and no germinal centres were found. A similar situation was seen in the mesenteric lymph nodes, in which, in conventional piglets, cells belonging to the plasmacyte series, as well as the germinal centres, proliferate by the 13th day. Differences were also found in the organization of the follicular lymphoid tissue in the wall of the terminal ileum. In germ-free piglets, the lymph follicles increased only very slowly in size during the observation period and germinal centres were absent, while in conventional piglots germinal centres were present from the 12th day. The view is expressed that the intestinal lymphoid tissue ought rather to be classified as peripheral lymphoid tissue.     

Recirculatory and sessile CD4+ T lymphocytes differ on CD45RC expression

CD4+ T cell subsets are unequally distributed in rat secondary lymphoid organs. Those with the memory phenotype CD45RClow Thy-1- L-selectin- are present at a higher frequency in Peyer's patches (PP) than in lymph nodes and spleen, and increase in numbers with age in all three tissues, particularly in the PP. Homing experiments revealed that CD4+ T cells that recirculate through secondary lymphoid organs are mainly CD45RChigh. It was also apparent that the ability of recirculating cells to enter different lymphoid organs varies; less cells enter PP than the spleen or lymph nodes. Our results also reveal the existence of a nonrecirculating population of CD4+ T cells in secondary lymphoid organs, which are predominantly, if not exclusively, CD45RClow. Our results show that secondary lymphoid organs differ in their CD4+ T cell subset composition as a consequence of having different ratios of recirculatory:nonrecirculatory CD4+ T cells, and these cells display a different CD45RC phenotype.     

Quantitative interrelationships between the T- and B-cell populations of mouse lymphoid organs]

The number of thymocytes and splenic T-lymphocytes correlate negatively. After the treatment of mice with cortisol, this negative correlation changes for a positive one. It is proposed that the negative correlation between cortisone-sensitive thymocytes and splenic T cells is mediated by cortisone-resistant thymocytes. The negative correlations were also found between amounts of T-cells in mesenteric lymph nodes and in Peyer's patches, the positive correlations being seen between numbers of splenic and lymph nodes T-lymphocytes. No correlations between B-cell populations in different organs were revealed. Apparently, correlations between lymphocyte populations reflect some aspect of hierachic structure of the lymphoid system.     

Selective emigration of suppressor T cells from Peyer's patches

The emigration of Peyer's patch lymphocytes to mesenteric lymph nodes was studied by injecting fluorescein isothiocyanate (FITC) directly into Peyer's patches. Using double immunofluorescence it was demonstrated that at 2 and 4 hr after FITC injection 70% of the labeled cells that migrated to mesenteric lymph nodes were T lymphocytes, although rat Peyer's patches contain only 15-20% T lymphocytes. At later time points after FITC injection this percentage of T cells derived from Peyer's patches gradually declined, most likely caused by selective interaction and/or retention inside the mesenteric lymph node. Determination of helper and suppressor T-cell subsets within this emigrating population showed an increased number of T suppressor cells migrating into mesenteric lymph nodes. The putative role of suppressor T cells in inducing systemic tolerance after oral antigen administration was discussed.     

No beneficial effects evident for Enterococcus faecium NCIMB 10415 in weaned pigs infected with Salmonella enterica serovar Typhimurium DT104

Salmonella enterica serovar Typhimurium DT 104 is the major pathogen for salmonellosis outbreaks in Europe. We tested if the probiotic bacterium Enterococcus faecium NCIMB 10415 can prevent or alleviate salmonellosis. Therefore, piglets of the German Landrace breed that were treated with E. faecium (n = 16) as a feed additive and untreated controls (n = 16) were challenged with S. Typhimurium 10 days after weaning. The presence of salmonellae in feces and selected organs, as well as the immune response, were investigated. Piglets treated with E. faecium gained less weight than control piglets (P = 0.05). The feeding of E. faecium had no effect on the fecal shedding of salmonellae and resulted in a higher abundance of the pathogen in tonsils of all challenged animals. The specific (anti-Salmonella IgG) and nonspecific (haptoglobin) humoral immune responses as well as the cellular immune response (T helper cells, cytotoxic T cells, regulatory T cells, γδ T cells, and B cells) in the lymph nodes, Peyer's patches of different segments of the intestine (jejunal and ileocecal), the ileal papilla, and in the blood were affected in the course of time after infection (P < 0.05) but not by the E. faecium treatment. These results led to the conclusion that E. faecium may not have beneficial effects on the performance of weaned piglets in the case of S. Typhimurium infection. Therefore, we suggest a critical discussion and reconsideration of E. faecium NCIMB 10415 administration as a probiotic for pigs.     

Differential effects of vasoactive intestinal peptide, substance P, and somatostatin on immunoglobulin synthesis and proliferations by lymphocytes from Peyer's patches, mesenteric lymph nodes, and spleen

We examined the effect of vasoactive intestinal peptide, substance P, and somatostatin on concanavalin A (1 microgram/ml)-induced lymphocyte proliferation and immunoglobulin (IgA, IgM, and IgG) synthesis by cells from spleens, Peyer's patches, and mesenteric lymph nodes. These neuropeptides (10(-7) to 10(-12) M) modulated immune responses in a dose-dependent manner. For a comparative study, neuropeptides were used at 10(-8) M concentration. Both vasoactive intestinal peptide and somatostatin significantly decreased DNA synthesis (30 to 50%), whereas substance P increased synthesis (40%) in lymphocytes from all organs tested. IgA synthesis was significantly altered by all of the neuropeptides tested, whereas IgM synthesis was less affected and IgG synthesis was virtually unchanged. Somatostatin inhibited IgA (20 to 50%) and IgM (10 to 30%) synthesis in lymphocytes from all three organs. Substance P increased IgA synthesis in mesenteric lymph nodes (50%), spleens (70%), and Peyer's patches (300%). It also increased IgM synthesis in Peyer's patches (20%) and spleens (30%), but was without effect on IgM synthesis in mesenteric lymph nodes. Vasoactive intestinal peptide increased the IgA response in mesenteric lymph nodes (20%) and spleens (30%), but inhibited IgA synthesis in lymphocytes from Peyer's patches (60%). Interestingly, in Peyer's patches, IgM synthesis was increased by vasoactive intestinal peptide (80%), whereas it was unchanged in mesenteric lymph nodes and spleen. Thus, not only did these neuropeptides have different effects on the production of different immunoglobulin isotypes, but their effect was also organ-specific. Because neuropeptides which are abundant in the intestine can modulate IgA and other immunoglobulin synthesis in vitro, they may play a significant regulatory role in mucosal immune responses in vivo.     

Lymphocyte traffic through lymph nodes and Peyer's patches of the rat: B- and T-cell-specific migration patterns within the tissue,and their dependence on splenic tissue

The migration routes of lymphocyte subsets through organ compartments are of importance when trying to understand the local events taking place during immune responses. We have therefore studied the traffic of B, T, CD4⁺, and CD8⁺ lymphocytes through lymph nodes and Peyer's patches. At various time points after injection into the rat, labeled lymphocytes were localized, and their phenotype characterized in cryostat sections using immunohistochemistry. Morphometry was also performed, and the recovery of ⁵¹Cr-labeled lymphocytes in these organs was determined. B and T lymphocytes entered the lymph nodes via the high endothelial venules in similar numbers. Most B lymphocytes migrated via the paracortex (T cell area) into the cortex (B cell area), and then back in substantial numbers into the paracortex. In contrast, T lymphocytes predominantly migrated into the paracortex and were rarely seen in the cortex. No obvious differences were seen between various lymph nodes and Peyer's patches and the routes of CD4⁺ and CD8⁺ lymphocytes. After injection of lymphocytes into animals with autotransplanted splenic tissue, the number of B lymphocytes that had migrated into the B cell area of lymph nodes and of Peyer's patches was significantly decreased, whereas CD4⁺ lymphocytes migrated in larger numbers into the T cell area of both organs.This study was supported by the Deutsche Forschungsgemein-schaft (SFB 244, A7).     

Naive, effector, and memory T lymphocytes efficiently scan dendritic cells in vivo: contact frequency in T cell zones of secondary lymphoid organs does not depend on LFA-1 expression and facilitates survival of effector T cells

Contact between T cells and dendritic cells (DCs) is required for their subsequent interaction leading to the induction of adaptive immune responses. Quantitative data regarding the contact frequencies of T cell subsets in different lymphoid organs and species are lacking. Therefore, naive, effector, and memory CD4 T cells were injected into rats in absence of the cognate Ag, and 0.5-96 h later, spleen, lymph nodes, and Peyer's patches were removed. Cryosections were analyzed for contact between donor T cells and endogenous DCs in the T cell zone, and donor cell proliferation. More than 60% of injected naive CD4 T cells were in contact with endogenous DCs at all time points and in all organs analyzed. Surprisingly, we were unable to detect any differences between naive, effector, and memory CD4 T cells despite different expression levels of surface molecules. In addition, contact frequency was similar for T cells in lymphoid organs of rats, mice, and humans; it was unaffected by the absence of LFA-1 (CD11a/CD18), and sustained effector T cells in an activated state. Thus, the architecture of the T cell zone rather than expression patterns of surface molecules determines the contact efficiency between T cells and DCs in vivo.     

Homing of germinal-center cells into germinal centers of lymph node via afferent lymphatics

Summary Affinity of lymphoid cells for the microenvironment of germinal centers (GC), as detectable in transfer experiments by rapid homing in spleen GC from the blood, is a capacity expressed by only a subset of lymphoid cells, in particular by those constituting a GC. However, when introduced into the blood stream, these cells do not home into GC of lymph nodes and gut-associated lymphoid tissues. To investigate further this homing inability for high endothelial venule (HEV)-containing lymphoid tissues, GC cells isolated from donor rabbit appendix were labeled in vitro with ³H-leucine and injected into an afferent lymph vessel of recipient popliteal lymph nodes. Draining lymph nodes were removed 15 min to 24 h after cell administration and prepared for radioautography. For reference, the migration of cells isolated from Peyer's patches and thoracic duct lymph was also studied. By use of appendix GC cells, large numbers of labeled cells were found to migrate into GCs of the outer cortex centripetally, i.e., from the subcapsular sinus through the lymphocyte corona into the GC proper. The same was observed for cells from Peyer's patches, although in smaller numbers. Thoracic duct lymphocytes were only localized in the lymphocyte corona and the deep cortex. Thus, appendix GC cells and a subpopulation of cells from Peyer's patches can reach lymph node GC, but only when administered intralymphatically. We conclude that cells expressing affinity for the GC microenvironment do so for both spleen and lymph node GC, but do not have the capacity to interact with the wall of HEV; its implication for the understanding of the dynamics of a GC reaction is discussed.Abbreviations GC germinal center - GCC germinal-center cells - AGCC appendix germinal-center cells - GCPC germinal-center precursor cells - GCSC germinal-center seeking cells - HEV high endothelial venules - SRBC sheep red blood cells - PP Peyer's patch - TDL thoracic duct lymphocytes - NCS newborn calf serum - PBS phosphate-buffered saline - PNA peanut agglutinin - LN lymph node - LC lymphocyte corona - DC deep cortex unit