The response of B cells in spleen, Peyer's patches, and lymph nodes to LPS and IL-4

The vast majority of B lymphocytes in the Peyer's patches (PP) and lymph nodes (LN) are memory cells or activated cells. Hence, in comparison to B lymphocytes in the spleen (SP), most B cells in these lymphoid organs have already encountered antigen. To further examine the ability of B cells in these peripheral lymphoid organs to respond to mitogens and interleukins in vitro, we have analyzed the ability of these cells (as compared to splenic B cells) to respond to LPS and LPS plus IL-4. Our results indicate that B cells from PPs and LNs proliferate poorly to LPS during the first 3 days of culture. In contrast, at later times, PP and LN B cells show enhanced proliferation as compared to splenic B cells. Furthermore, the addition of Interleukin-4 (IL-4) changes the proliferative activity of B cells from PPs and LNs, had only a minimal effect on splenic B cells. Hence, high doses of IL-4 (100 units/ml) enhance the proliferative rate of B cells from PPs and LNs early after activation, and have a suppressive effect at later times. The enhanced response of cells in PPs and LNs is further manifested by the presence of larger numbers of sIgG1+ cells 4 days after activation with LPS plus IL-4 and at 5 days these cells also secrete proportionally more IgG1 than splenic B cells. Enhanced IgG1 secretion is reflected in the methylation pattern of the s gamma 1 switch region of these cells. In cells from PP and LN cultured with LPS plus IL-4, most alleles containing the s gamma 1 region are demethylated or partly deleted, reflecting activation of this region of the Ig gene complex. In contrast, in splenic B cells, half the alleles remain in germline configuration. Our results suggest the presence of larger numbers of "preactivated" B cells in PPs and LNs as compared to spleen. These cells more rapidly secrete Ig following stimulation with LPS plus IL-4 in the absence of significant proliferation.     

Peyer's patches are required for the induction of rapid Th1 responses in the gut and mesenteric lymph nodes during an enteric infection

The Peyer's patches (PP) and mesenteric lymph nodes (MLN) are structural components of the gut-associated lymphoid tissues and contribute to the induction of immune responses toward infection in the gastrointestinal tract. These secondary lymphoid organs provide structural organization for efficient cellular interactions and the initiation of primary adaptive immune responses against infection. Immunity against primary infection with the enteric apicomplexan parasite, Eimeria vermiformis, depends on the rapid induction of local Th1 responses. Lymphotoxin (LT)-deficient mice which have various defects in secondary lymphoid organs were infected with E. vermiformis. The relative susceptibility of LTalpha(-/-), LTbeta(-/-), LTalpha(+/-)beta(+/-) mice and bone marrow chimeras, indicated that rapid protective Th1 responses required both PP and MLN. Moreover, the timing of Th1 induction in both MLN and gut was dependent on the presence of PP suggesting a level of cooperation between immune responses induced in these distinct lymphoid structures. The delay in Th1 induction was attributable to the delayed arrival of a broad range of dendritic cell subsets in the MLN and a substantial reduction of CD8alpha(-)CD11b(high) B220(-) dendritic cells in PP-deficient mice.     

Microscopic structure of the mesenteric lymph nodes of monkeys]

The structure and cytoarchitectonics of mesenterial lymph nodes were studied in thin histological sections by different methods. Under study were 5 rhesus monkeys and 3 hamadryas baboons. The square surface of different structural elements of the nodes (the cortical and medullary substances, follicles, the connective tissue framework, sinuses) occupied by them in sections was calculated and the amount of cellular elements was determined (%). Comparison of the data obtained in rhesus monkeys and baboons speaks of certain species-specific features of the organs under study. The morphological picture of lymph node sections in baboons (as compared with rhesus monkeys) might suggest earlier ageing of nodes in baboons.     

Ultrastructural study of mesenteric lymph nodes in old rats

The large mononuclear cells showed the features of mononuclear phagocytes and were mainly characterised by a large number of vacuolar structures. The results suggest that there is storage of lipids and mucosubstances, probably in enlarged lysosomes.     

Internal structure of the postcapillary high-endothelial venules of rodent lymph nodes and Peyer's patches and the transendothelial lymphocyte passage

Scanning electron microscopy (SEM) shows that the postcapillary high-endothelial venules of lymph nodes and Peyer's patches consist of two segments each with a different surface relief: a proximal segment with a cobblestone surface pattern and a distal segment of interlacing cytoplasmic plates. Both segments have deep adluminal crevices in which lymphocytes are lodged. The internal structural configuration of this endothelium has been examined by transmission electron microscopy (TEM) of serial sections of lymph nodes and Peyer's patches of mice, rats, and guinea pigs. The serial sections revealed that the endothelial cell bodies and their cytoplasmic extensions were disposed in a direction generally lateral to the luminal surface and intruded into the intercellular spaces of similarly disposed neighboring endothelial cells, resulting in a complex interlacing cellular pattern. Lymphocytes penetrated the endothelial cell body and secondarily followed an intracellular pathway through which they entered the extravascular compartment. At the exposed surfaces of the adluminal venule wall, recirculating lymphocytes were seen in SEM images to enter the endothelium by penetrating the endothelial cell body. The mode of migration of lymphocytes lodged in the endothelial crevices could be determined by SEM and has been examined by TEM of serial sections. At these locations as at the exposed surfaces, lymphocytes also entered the venule by penetrating the endothelial cell body. At both sites this transcellular pathway was followed by lymphocyte entry into the intercellular spaces from which they migrated into the extravascular compartment.     

Lymphocyte recognition of lymph node high endothelium. VI. Evidence of distinct structures mediating binding to high endothelial cells of lymph nodes and Peyer's patches

Lymphocytes migrate from blood into lymph nodes (LN) and Peyer's patches (PP) of rats specifically at segments of venules lined by high endothelium (HEV). We previously identified and isolated a lymphocyte surface component termed high endothelial binding factor (HEBF) that appears to be involved in lymphocyte adhesion to high endothelial cells of LN. HEBF has also been isolated from thoracic duct lymph and is antigenically related to the cell surface component. Soluble HEBF derived from detergent lysates of thoracic duct lymphocytes (TDL) or directly from lymph has affinity for HEVLN in vitro, and is able to block sites where lymphocytes would normally attach. In the present study, lymphocyte binding sites of HEVLN and HEVPP were investigated through the use of lymph-derived HEBF and rabbit antibody to this factor. The results show that treatment of rat TDL with anti-HEBF Fab did not block binding to HEVPP, even though adhesion to HEVLN was reduced by 80% or more. Similarly, HEBF isolated by anti-HEBF F(ab')2 affinity chromatography blocked lymphocyte binding sites of HEVLN but not HEVPP. This material is therefore designated HEBFLN, and antibody to it is designated anti-HEBFLN Ig. Fractionation of thoracic duct lymph revealed that it contained an antigenically distinct component, HEBFPP, which blocked lymphocyte binding to HEVPP but not to HEVLN. Lymph components precipitating between 40 and 60% (NH4)2SO4 saturation contained both factors, which were separated from the bulk of lymph proteins by DEAE-Sepharose chromatography and then from each other by fractionation on the anti-HEBFLN F(ab')2-Sepharose column. The unbound fraction from this column contained HEBFPP, which was then partially purified by CM-Sepharose filtration. HEBFPP appeared to be a glycoprotein because it was destroyed by trypsin, bound to lentil lectin, and was eluted with alpha-methyl-mannoside. Together, the results demonstrate the existence of two antigenically distinct species of HEBF, and imply that lymphocyte binding sites of HEVLN and HEVPP are structurally different. We interpret the results to mean that distinct high endothelial adhesion molecules on lymphocytes mediate their entry into LN and PP.     

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.     

Local antibody response in Peyer's patches to the orally administered dietary protein antigen

To understand local antibody production to dietary protein antigens in the gut, the reactivity of the monoclonal antibodies (mAbs) from Peyer's patches of BALB/c mice raised against orally administered hen egg lysozyme (HEL) was studied. These mAbs were of IgG1 (7 clones), IgA (5 clones) and IgM (13 clones) isotypes. Some of the HEL-binding mAbs preferentially reacted with reduced, carboxy-methylated HEL, rather than with native HEL. MAbs of the IgA and IgM isotypes had cross-reactivity with other unrelated environmental antigens such as E. coli, single-strand DNA, and soluble components of mouse food. In contrast, the IgG1 mAbs did not cross-react with these antigens. The average of the Kd values for HEL of these mAbs was in the order of 10(-6) M, which is moderately higher than those of mAbs from the preimmune repertoire. These results suggest that, under normal physiological conditions, orally administered dietary proteins predominantly induce the local production of polyreactive IgA/IgM antibodies cross-reacting with environmental luminal antigens.     

Morphology of mesenteric lymph nodes after balneologic procedures

Strong and weak sulfate baths produce certain increase in amount and in area of the lymphoid noduli with the germinative center, in the deep cortex and a decrease in the relative area of the medullary substance, while iodobromine baths facilitate to an outgrowth of the medullary cords and to ectasia of sinus lumens. After the balneoprocedures lymphoid noduli appear in the deep cortex; amount of destructive cells in the medullary sinuses, in the medullary cords and in the intermedullary zone decreases; amount of mast cells, eosinophiles and neutrophiles increases (slightly). Blast transformation of small lymphocytes and increase in number of middle lymphocytes are observed in the germinative centers.     

Intestinal gamma delta T cells develop in mice lacking thymus, all lymph nodes, Peyer's patches, and isolated lymphoid follicles

Through analysis of athymic (nu/nu) mice carrying a transgenic gene encoding GFP instead of RAG-2 product, it has recently been reported that, in the absence of thymopoiesis, mesenteric lymph nodes and Peyer's patches (PP) but not gut cryptopatches are pivotal birthplace of mature T cells such as the thymus-independent intestinal intraepithelial T cells (IEL). To explore and evaluate this important issue, we generated nu/nu mice lacking all lymph nodes (LN) and PP by administration of lymphotoxin-beta receptor-Ig and TNF receptor 55-Ig fusion proteins into the timed pregnant nu/+ mice that had been mated with male nu/nu mice (nu/nu LNP- mice). We also generated nu/nu aly/aly (aly, alymphoplasia) double-mutant mice that inherently lacked all LN, PP, and isolated lymphoid follicles. Although gammadelta-IEL were slightly smaller in number than those in nu/nu mice, substantial colonization of gammadelta-IEL was found to take place in the intestinal epithelia of nu/nu LNP- and nu/nu aly/aly mice. Notably, the population size of a major CD8alphaalpha+ gammadelta-IEL subset was maintained, the use of TCR-gamma-chain variable gene segments by these gammadelta-IEL was unaltered, and the development of cryptopatches remained intact in these nu/nu LNP- and nu/nu aly/aly mice. These findings indicate that all LN, including mesenteric LN, PP, and isolated lymphoid follicles, are not an absolute requirement for the development of gammadelta-IEL in athymic nu/nu mice.     

Late effect of carbon disulfide on the lymph nodes in rats]

Cell composition of the cortical plateau, medullary cords and lymphoid nodules++ has been determined in 180 Wistar rats in 2 weeks, 1 and 3 months after inhalation of carbon disulfate vapour for 2, 7 and 14 days in a maximum permissible concentration (1 mg/m3) and in the control group. In 2 weeks after cessation of the vapour inhalation activity of lymphocytopoiesis, blastopoiesis, cell differentiation decreases, macrophagal and plasmocytic reactions are weakly manifested. In 1 month certain signs of compensatory-adaptive reaction are noted; they are seen as increasing proliferative processes and activation of cell differentiation in the lymphoid nodules++ and a sharp plasmatization of the medullary cords. In 3 months after the experiment retardation of lymphocytopoiesis is still definitely manifested in the cortical plateau and medullary cords and essential destructive processes are observed against the background of local increase of the functional activity of the lymphoid nodules++.     

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).     

Features of the morphofunctional response of Peyer's patches in rats during the course of traumatic shock and the early post-shock period

The reaction of Peyer's patches to trauma manifests in: 1) vascular changes; 2) primary or stressor cells shifts recordable in traumatic shock, characterized by depletion of patch follicles by minor lymphocytes; 3) secondary changes associated with the onset of reparative processes; 4) the increased macrophagal activity detectable during the entire period of the traumatic shock and in the early post-shock period. It is suggested that changes seen may be due to endotoxin that penetrates from the intestine.