Migratory patterns of thoracic duct lymphocytes into bronchus-associated lymphoid tissue of immunized rats

The bronchus-associated-lymphoid tissue (BALT) an unique lymphoid organ in man and animals

The development structure and number of bronchus-associated lymphoid tissue (BALT) will be described in many different animals (like chicken, rabbit, mouse, rat, farm animals and particular the pig, monkey) and these data compared to healthy man and in human diseases. The term induced BALT should not be used because it is a tertiary lymphoid structure, which lacks the contact to a bronchus and does not consist of the important area (dome area) which is essential for antigen uptake of microbial stimuli, which are essential in the development of BALT. Mycoplasma seems to play a critical role as shown in pigs but there not been documented in other species like rabbits. More studies have to be performed in health and disease (e.g. in apes) to document the structural and functional basis to use BALT as an entry site for vaccination protocols.

Role of iBALT in Respiratory Immunity

Pulmonary respiration inevitably exposes the mucosal surface of the lung to potentially noxious stimuli, including pathogens, allergens, and particulates, each of which can trigger pulmonary damage and inflammation. As inflammation resolves, B and T lymphocytes often aggregate around large bronchi to form inducible Bronchus-Associated Lymphoid Tissue (iBALT). iBALT formation can be initiated by a diverse array of molecular pathways that converge on the activation and differentiation of chemokine-expressing stromal cells that serve as the scaffolding for iBALT and facilitate the recruitment, retention, and organization of leukocytes. Like conventional lymphoid organs, iBALT recruits naïve lymphocytes from the blood, exposes them to local antigens, in this case from the airways, and supports their activation and differentiation into effector cells. The activity of iBALT is demonstrably beneficial for the clearance of respiratory pathogens; however, it is less clear whether it dampens or exacerbates inflammatory responses to non-infectious agents. Here, we review the evidence regarding the role of iBALT in pulmonary immunity and propose that the final outcome depends on the context of the disease.

Osteopathic lymphatic pump techniques to enhance immunity and treat pneumonia

Pneumonia is a common cause of morbidity and mortality worldwide. While antibiotics are generally effective for the treatment of infection, the emergence of resistant strains of bacteria threatens their success. The osteopathic medical profession has designed a set of manipulative techniques called lymphatic pump techniques (LPT), to enhance the flow of lymph through the lymphatic system. Clinically, LPT is used to treat infection and oedemaand might be an effective adjuvant therapy in patients with pneumonia.The immune system uses the lymphatic and blood systems to survey to rid the body of pathogens; however, only recently have the effects of LPT on the lymphatic and immune systems been investigated. This short review highlightsclinical and basic science research studies that support the use of LPT to enhance the lymphatic and immune systems and treat pneumonia, and discusses the potential mechanisms by which LPT benefits patients with pneumonia.

Lymphatic pump treatment augments lymphatic flux of lymphocytes in rats

BACKGROUND

Lymphatic pump techniques (LPT) are used by osteopathic practitioners for the treatment of edema and infection; however, the mechanisms by which LPT enhances the lymphatic and immune systems are poorly understood.

METHODS AND RESULTS

To measure the effect of LPT on the rat, the cisterna chyli (CC) of 10 rats were cannulated and lymph was collected during 4 min of 1) pre-LPT baseline, 2) 4 min LPT, and 3) 10 min post-LPT recovery. LPT increased significantly (p < 0.05) lymph flow from a baseline of 24 ± 5 μl/min to 89 ± 30 μl/min. The baseline CC lymphocyte flux was 0.65 ± 0.21 × 10⁶ lymphocytes/min, and LPT increased CC lymphocyte flux to 6.10 ± 0.99 × 10⁶ lymphocytes/min (p < 0.01). LPT had no preferential effect on any lymphocyte population, since total lymphocytes, CD4+ T cells, CD8+ T cells, and B cell numbers were similarly increased. To determine if LPT mobilized gut-associated lymphocytes into the CC lymph, gut-associated lymphocytes in the CC lymph were identified by staining CC lymphocytes for the gut homing receptor integrin α4β7. LPT significantly increased (p < 0.01) the flux of α4β7 positive CC lymphocytes from a baseline of 0.70 ± 0.03 × 10⁵ lymphocytes/min to 6.50 ± 0.10 × 10⁵ lymphocytes/min during LPT. Finally, lymphocyte flux during recovery was similar to baseline, indicating the effects of LPT are transient.

CONCLUSIONS

Collectively, these results suggest that LPT may enhance immune surveillance by increasing the numbers of lymphocytes released in to lymphatic circulation, especially from the gut associated lymphoid tissue. The rat provides a useful model to further investigate the effect of LPT on the lymphatic and immune systems.

Bronchus-associated lymphoid tissue (BALT) structure and function

Bronchus-associated lymphoid tissue (BALT) is a constitutive mucosal lymphoid tissue adjacent to major airways in some mammalian species, including rats and rabbits, but not humans or mice. A related tissue, inducible BALT (iBALT), is an ectopic lymphoid tissue that is formed upon inflammation or infection in both mice and humans and can be found throughout the lung. Both BALT and iBALT acquire antigens from the airways and initiate local immune responses and maintain memory cells in the lungs. Here, we discuss the development and function of BALT and iBALT in the context of pulmonary immunity to infectious agents, tumors, and allergens as well as autoimmunity and inflammatory diseases of the lung.

Lymphatic pump treatment mobilizes leukocytes from the gut associated lymphoid tissue into lymph

BACKGROUND

Lymphatic pump techniques (LPT) are used clinically by osteopathic practitioners for the treatment of edema and infection; however, the mechanisms by which LPT enhances lymphatic circulation and provides protection during infection are not understood. Rhythmic compressions on the abdomen during LPT compress the abdominal area, including the gut-associated lymphoid tissues (GALT), which may facilitate the release of leukocytes from these tissues into the lymphatic circulation. This study is the first to document LPT-induced mobilization of leukocytes from the GALT into the lymphatic circulation.

METHODS AND RESULTS

Catheters were inserted into either the thoracic or mesenteric lymph ducts of dogs. To determine if LPT enhanced the release of leukocytes from the mesenteric lymph nodes (MLN) into lymph, the MLN were fluorescently labeled in situ. Lymph was collected during 4 min pre-LPT, 4 min LPT, and 10 min following cessation of LPT. LPT significantly increased lymph flow and leukocytes in both mesenteric and thoracic duct lymph. LPT had no preferential effect on any specific leukocyte population, since neutrophil, monocyte, CD4+ T cell, CD8+ T cell, IgG+B cell, and IgA+B cell numbers were similarly increased. In addition, LPT significantly increased the mobilization of leukocytes from the MLN into lymph. Lymph flow and leukocyte counts fell following LPT treatment, indicating that the effects of LPT are transient.

CONCLUSIONS

LPT mobilizes leukocytes from GALT, and these leukocytes are transported by the lymphatic circulation. This enhanced release of leukocytes from GALT may provide scientific rationale for the clinical use of LPT to improve immune function.

Reproductive phase dependent variation in lung-associated immune system (LAIS) and expression of melatonin receptors (Mel1a and Mel1b) in the lung of the Jungle-Bush Quail (Perdicula asiatica)

The present study was performed to assess the variation of the lung-associated immune system (LAIS) in the Jungle-Bush Quail ( Perdicula asiatica (Latham, 1790)) during two different reproductive phases when differences in the circulatory level of hormones (melatonin and gonadal steroid) and environmental conditions were maximum. We noted high significant variation in size and number of bronchus-associated lymphoid tissue (BALT) nodules, as well as in the size and number of non-BALT nodules, during the reproductively inactive phase (RIP; December) compared with the active phase (RAP; June). We also noted high significant variation in the percent stimulation ratio of lung lymphocyte, as well as in the concentrations of plasma melatonin and melatonin receptors, during RIP compared with RAP. Testosterone level and number of macrophages in lungs were high during RAP. Thus, we suggest that the LAIS had reproductive phase dependent variation, which could be due to (i) variation in environmental factors (photoperiod, temperature, and humidity) and (ii) circulatory level of hormones (melatonin and testosterone). Because of the importance of melatonin in avian immune regulation, we assess and document the expression of melatonin receptor types Mel1a and Mel1b in the avian lung, which suggest that the lung is a target organ for melatonin and that melatonin is an immunomodulator for lung-associated immunity in birds.

Transferred T cells preferentially adhere in the BALT of CD26-deficient recipient lungs during asthma

The multifunctional glycoprotein CD26/dipeptidyl peptidase 4 (DP4) has a DP activity, plays a role during T-cell activation, and interacts with several proteins, including extracellular matrix (ECM)-proteins. The latter have been studied mainly in the context of experimental metastasis. The potential role of CD26 for T-cell adhesion could be of major interest. Here, a coisogenic transfer of CFSE-labelled T cells was performed after isolation from CD26-expressing or CD26-deficient F344 rat donors and subsequent cross-transfer to recipients of the other substrain. Their recovery in the lungs was quantified using flow cytometry, a histochemical activity assay, as well as immunohistochemistry and morphometry. Under naïve conditions there were neither differences in the numbers of recovered T cells nor in their preferential anatomical sites of adhesion. The induction of an asthma-like inflammation, however, led to a site-preferential adhesion of T cells in the bronchus-associated lymphatic tissue (BALT). In this compartment of the lungs, surprisingly, significantly more T cells were found in CD26-deficient recipient lungs, regardless of the origin of the transferred T cells. These findings demonstrate a negative regulatory role of the BALT-specific expression of CD26 in T-cell adhesion during an asthma-like inflammation. Considering the pattern of cellular re-distribution it is not very likely that CD26 expressed on T cells and/or endothelial cells represents a significant factor in T-cell adhesion in vivo. Instead, the present findings suggest that the lack of the CD26 peptidase function in BALT might cause an overflow of a T-cell chemoattractant, which yet remains to be identified.

Effect of LLLT Ga-Al-As (685 nm) on LPS-induced inflammation of the airway and lung in the rat

The purpose of this study was to investigate the effect of low level laser therapy (LLLT) on male Wistar rat trachea hyperreactivity (RTHR), bronchoalveolar lavage (BAL) and lung neutrophils influx after Gram-negative bacterial lipopolyssacharide (LPS) intravenous injection. The RTHR, BAL and lung neutrophils influx were measured over different intervals of time (90 min, 6 h, 24 h and 48 h). The energy density (ED) that produced an anti-inflammatory effect was 2.5 J/cm(2), reducing the maximal contractile response and the sensibility of trachea rings to methacholine after LPS. The same ED produced an anti-inflammatory effect on BAL and lung neutrophils influx. The Celecoxib COX-2 inhibitor reduced RTHR and the number of cells in BAL and lung neutrophils influx of rats treated with LPS. Celecoxib and LLLT reduced the PGE(2) and TXA(2) levels in the BAL of LPS-treated rats. Our results demonstrate that LLLT produced anti-inflammatory effects on RTHR, BAL and lung neutrophils influx in association with inhibition of COX-2-derived metabolites.