Treatment outcome, toxicity, and quality of life of patients with bronchus-associated lymphoid tissue lymphoma.

The disease failure patterns and optimal treatment of bronchus-associated lymphoid tissue (BALT) lymphoma are unknown. This retrospective study involved 71 patients with primary BALT lymphoma who had received radiotherapy (RT), surgery, immunochemotherapy (IC), or observation. The median follow-up time was 66 months. The 5-year overall survival and lymphoma-specific survival were 91.2% and 96.1%, respectively, and were not significantly different among treatments. The 5-year cumulative incidence of overall failure for RT, surgery, IC, and observation was 0%, 9.7% (p = .160), 30.8% (p = .017), and 31.3% (p = .039). There was no grade ≥3 toxicity in RT group according to the CTCAE 5.0 reporting system. Quality of life (QoL) was at similarly good levels among the treatment groups. BALT lymphoma had a favorable prognosis but persistent risk of relapse after IC or observation. Given the very low disease failure risk and good QoL, RT remains an effective initial treatment for BALT lymphoma.

BALT lymphoma has a favorable prognosis but a persistent progression and relapse risk.Radiotherapy is associated with lower failure of disease progression and relapse, low toxicity and good quality of life.

Pathological analysis and etiological assessment of pulmonary lesions and its association with pleurisy in slaughtered pigs.

The intensification of pig farming has posed significant challenges in managing and preventing sanitary problems, particularly diseases of the respiratory complex. Monitoring at slaughter is an important control tool and cannot be overstated. Hence, this study aimed at characterizing both macroscopical and microscopical lesions and identifying the Actinobacillus pleuropneumoniae (APP), Mycoplasma hyopneumoniae (Mhyo), and Pasteurella multocida (PM) associated with pleurisy in swine. For this, a selected slaughterhouse in São Paulo State underwent a thorough examination of carcasses on the slaughter line, followed by lung sampling. The carcasses and lungs underwent macroscopical examination and were classified according to the score of pleurisy and lung samples were allocated into five groups, being: G0: score 0 - no lesions; G1: score 1; G2: score 2; G3: score 3; and G4: score 4. In total, 217 lung fragments were collected, for the histopathological evaluation and detection of the following respiratory pathogens: APP, Mhyo, and PM by qPCR. The results demonstrated that Mhyo and APP were the most prevalent etiological agents (single and co-identification) in lung samples, in different scores of pleurisies, while bronchopneumonia and bronchus-associated lymphoid tissue (BALT) hyperplasia lesions were the most frequent histopathological findings. Positive correlations were found between the quantification of APP DNA with 1) the score of pleurisy (R=0.254); 2) with the score of lung consolidation in all lung lobes (R=0.181 to R=0.329); and 3) with the score of lung consolidation in the entire lung (R=0.389). The study brings relevant information regarding the main bacterial pathogens associated with pleurisy in pigs and helps with understanding the relationship between the abovementioned pathogens and their impact on the respiratory health of pigs.

Very low-dose radiotherapy for extranodal marginal zone lymphoma of bronchus-associated lymphoid tissue.

Extranodal marginal zone lymphoma of bronchus-associated lymphoid tissue (BALT) is a rare cancer for which optimal treatment strategies are undefined. Retrospective analyses suggest excellent outcomes with surgical resection for localized BALT lymphoma; however, the role of radiotherapy remains underexplored. We report the largest-to-date single-center analysis of 13 primary BALT lymphoma patients treated with radiotherapy. Of 15 treated lesions, we report a 100% response rate with complete response (CR) achieved in 67% of lesions. Among 10 lesions treated with very low-dose radiotherapy (VLDRT; 4 Gray [Gy]), 6 (60%) achieved a CR; among 5 lesions treated with full-dose radiotherapy (24-36 Gy), 4 (80%) achieved a CR. There were no local recurrences. Only one patient, treated with 30 Gy, developed an acute grade 3/4 toxic effect. There were no events of radiation-induced secondary malignancies. Our institutional experience indicates that radiotherapy, including VLDRT, is a safe and effective treatment for primary BALT lymphoma.

Histological and immunohistochemical characterization of mucosa-associated lymphoid tissue and antigen-presenting cells in trachea and lung of cattle.

The presence of bronchus-associated lymphoid tissue (BALT) and its structural components has been described in different healthy animal species and in animals with diseases of the respiratory tract. In contrast to normal mammals, BALT is absent in healthy human adult lungs, but has been found in the lungs of children. The histological characteristics of organized mucosa-associated lymphoid tissue (MALT), its subsets of immune cells and their in situ distribution in the lung of healthy subadult and adult cattle shows close similarities with BALT in humans and other animal species such as sheep, horses and pigs. This study clearly demonstrates that organized MALT also occurs in the tracheal mucosa of cattle. The absence of tracheal MALT and BALT in calves suggest that these structures are not constitutive. In the mucosa of bovine trachea, bronchi and bronchioli, MHC II+ and CD11c+ dendritic cells (DCs) are located in the epithelium and in the lamina propria mucosae. These DCs are already present in calves soon after birth. Examination of tangential epithelial sheets shows that in the bovine tracheal epithelium, like in man and rat, a dense network of MHC II+ and CD11c+ DCs exists and that their number is considerably higher than in conventional transverse sections. In the bovine tracheal and bronchial epithelium, MHC II+ DCs are extending their dendrites towards the lumen indicating that these DCs possibly are involved in sampling of luminal antigens. The presence of significantly higher numbers of MHC II+ DCs in the tracheal and bronchial/bronchiolar mucosa of older cattle in than in calves possibly results from local stimulation with exogenous antigens during postnatal life. Detection of DCs expressing the costimulatory molecules CD80 and CD86 in calves and cattle suggests maturation of DCs, which is most likely induced by stimulation with exogenous antigens.

Morphology of Lymphoid Tissue in the Lungs of Guinea Pigs Infected with Mycobacterium bovis against the Background of Vaccine Immunity and the Action of Betulin and Its Derivatives.

Tuberculosis caused by Mycobacterium bovis is a serious problem for animal and human health worldwide. A promising concept for the design of anti-tuberculosis drugs is the conjugation of an immunogenic fraction isolated from bacterial vaccines with a stimulating component. Taking this principle as a basis, conjugates based on BCG antigens with betulin and its derivatives (betulonic and betulinic acids) were designed. The aim of this research was to study the morphological changes in the lymphoid tissue associated with the bronchial mucosa lungs (BALT) in guinea pigs sensitized with experimental conjugates using a model of experimental tuberculosis. The results showed a significant decrease in the BALT response, expressed by a decrease in the diameter of lymphatic follicles and a decrease in their activity when exposed to conjugates based on BCG antigens with betulin and, especially, with betulonic acid, with a visually greater number of plasma cells observed in the lung tissues of guinea pigs of these groups. The absence of tuberculous foci and low BALT activity in the lungs of animals treated with betulin and betulonic acid are probably associated with the activation of humoral immunity under the action of these conjugates.

A guide to oral vaccination: Highlighting electrospraying as a promising manufacturing technique toward a successful oral vaccine development.

Most vaccines approved by regulatory bodies are administered via intramuscular or subcutaneous injections and have shortcomings, such as the risk of needle-associated blood infections, pain and swelling at the injection site. Orally administered vaccines are of interest, as they elicit both systemic and mucosal immunities, in which mucosal immunity would neutralize the mucosa invading pathogen before the onset of an infection. Hence, oral vaccination can eliminate the injection associated adverse effects and enhance the person's compliance. Conventional approaches to manufacturing oral vaccines, such as coacervation, spray drying, and membrane emulsification, tend to alter the structural proteins in vaccines that result from high temperature, organic and toxic solvents during production. Electrohydrodynamic processes, specifically electrospraying, could solve these challenges, as it also modulates antigen release and has a high loading efficiency. This review will highlight the mucosal immunity and biological basis of the gastrointestinal immune system, different oral vaccine delivery approaches, and the application of electrospraying in vaccines development.

Extranodal Marginal Zone Lymphoma: Pathogenesis, Diagnosis and Treatment.

Extranodal Marginal Zone Lymphoma (EMZL lymphoma) is an indolent B-cell lymphoma with a median age at diagnosis of about 60 years. It accounts for 7-8% of all B-cell lymphomas. It can occur in various extranodal sites, including stomach, lung, ocular adnexa, and skin; furthermore, the disseminated disease can be found in 25-50% of cases. Several infectious agents, such as Helicobacter pylori (H. Pylori) in the case of gastric Mucosa Associated Lymphoid Tissue (MALT) Lymphoma, can drive the pathogenesis of this cancer, through the autoantigenic stimulation of T cells, but there may also be other factors participating such autoimmune diseases. Initial staging should include total body computed tomography, bone marrow aspirate, and endoscopic investigation if indicated. Fluorescence in situ hybridization (FISH), should be performed to detect the presence of specific chromosomal translocations involving the MALT1 and BCL10 genes, which leads to the activation of the NF-κB signaling pathway. Depending on the location and dissemination of the disease, different therapeutic choices may include targeted therapy against the etiopathogenetic agent, radiotherapy, immunochemotherapy, and biological drugs. The purpose of this review is to illustrate the complex biology and the diagnosis of this disease and to better define new treatment strategies.

Anti-cyclic citrullinated peptide antibody-positive rheumatoid arthritis caused by bacterial organizing pneumonia in a patient with Sjogren's syndrome.

A 58-year-old woman with a history of Sjogren's syndrome was admitted to our hospital with cough, decreased right lung breath sounds and arthralgia in both thumbs. Chest computed tomography showed consolidation with air bronchogram in the right lung. Levels of anti-cyclic citrullinated peptide antibody and rheumatoid factor levels were significantly elevated. She was diagnosed with rheumatoid arthritis induced by bacterial organizing pneumonia. Treatment with salazosulfapyridine was added for rheumatoid arthritis and arthralgia gradually improved. This case highlights that respiratory infections could lead to anti-cyclic citrullinated peptide antibody-positive rheumatoid arthritis in patients with Sjogren's syndrome.

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.

CXCL13 is expressed in a subpopulation of neuroendocrine cells in the murine trachea and lung.

The conducting airways are lined by distinct cell types, comprising basal, secretory, ciliated, and rare cells, including ionocytes, solitary cholinergic chemosensory cells, and solitary and clustered (neuroepithelial bodies) neuroendocrine cells. Airway neuroendocrine cells are in clinical focus since they can give rise to small cell lung cancer. They have been implicated in diverse functions including mechanosensation, chemosensation, and regeneration, and were recently identified as regulators of type 2 immune responses via the release of the neuropeptide calcitonin gene-related peptide (CGRP). We here assessed the expression of the chemokine CXCL13 (B cell attracting chemokine) by these cells by RT-PCR, in silico analysis of publicly available sequencing data sets, immunohistochemistry, and immuno-electron microscopy. We identify a phenotype of neuroendocrine cells in the naïve mouse, producing the chemokine CXCL13 predominantly in solitary neuroendocrine cells of the tracheal epithelium (approx. 70% CXCL13+) and, to a lesser extent, in the solitary neuroendocrine cells and neuroepithelial bodies of the intrapulmonary bronchial epithelium (< 10% CXCL13+). In silico analysis of published sequencing data of murine tracheal epithelial cells was consistent with the results obtained by immunohistochemistry as it revealed that neuroendocrine cells are the major source of Cxcl13-mRNA, which was expressed by 68-79% of neuroendocrine cells. An unbiased scRNA-seq data analysis of overall gene expression did not yield subclusters of neuroendocrine cells. Our observation demonstrates phenotypic heterogeneity of airway neuroendocrine cells and points towards a putative immunoregulatory role of these cells in bronchial-associated lymphoid tissue formation and B cell homeostasis.

Intranasal Delivery of MVA Vector Vaccine Induces Effective Pulmonary Immunity Against SARS-CoV-2 in Rodents.

Antigen-specific tissue-resident memory T cells (Trms) and neutralizing IgA antibodies provide the most effective protection of the lungs from viral infections. To induce those essential components of lung immunity against SARS-CoV-2, we tested various immunization protocols involving intranasal delivery of a novel Modified Vaccinia virus Ankara (MVA)-SARS-2-spike vaccine candidate. We show that a single intranasal MVA-SARS-CoV-2-S application in mice strongly induced pulmonary spike-specific CD8+ T cells, albeit restricted production of neutralizing antibodies. In prime-boost protocols, intranasal booster vaccine delivery proved to be crucial for a massive expansion of systemic and lung tissue-resident spike-specific CD8+ T cells and the development of Th1 - but not Th2 - CD4+ T cells. Likewise, very high titers of IgG and IgA anti-spike antibodies were present in serum and broncho-alveolar lavages that possessed high virus neutralization capacities to all current SARS-CoV-2 variants of concern. Importantly, the MVA-SARS-2-spike vaccine applied in intramuscular priming and intranasal boosting treatment regimen completely protected hamsters from developing SARS-CoV-2 lung infection and pathology. Together, these results identify intramuscular priming followed by respiratory tract boosting with MVA-SARS-2-S as a promising approach for the induction of local, respiratory as well as systemic immune responses suited to protect from SARS-CoV-2 infections.

Temporospatial characterization of the bronchus associated lymphoid tissue (BALT) of the one humped camel (Camelus dromedarius).

BACKGROUND: Bronchial-associated lymphoid tissue (BALT) is responsible for the local immune response of the lung against airborne infections. The structure of this tissue varies according to species and age. AIM: The aim of this study was to describe the possible age-related structural variation of the BALT of the one humped camel. MATERIAL AND METHODS: Fresh specimens from both lungs of 15 clinically healthy male camels (10 months-12 years) were studied with light and electron microscopes. RESULTS: The BALT in the camel was variable from few lymphocytes to well-organized lymphoid tissue with a clear germinal center. The BALT of the bronchi is a constant lymphoid tissue in young and adult camels which may be of the large size with clear germinal center in response to repeated immune reaction and involutes in old age. The BALT of the bronchioles may be induced and develops mainly due to an immune reaction and showed great morphological variations and observed in different ages. High endothelial venules were associated with BALT in the bronchi but not with that of the bronchioles. The BALT-associated epithelium was tall pseudostratified columnar ciliated epithelium with goblet cells in the extrapulmonary bronchi changed to pseudostratified columnar ciliated epithelium mucous secreting cells in the intrapulmonary bronchi and simple columnar ciliated to simple cuboidal epithelium with Clara cells without goblet cells or mucous secreting cells in the bronchioles. CONCLUSIONS: The BALT of the bronchi is a constant lymphoid tissue in young and adult camels and involutes in old age. The BALT of the bronchioles may be induced and develops mainly due to an immune reaction and observed in different ages.

Primary Pulmonary B-Cell Lymphoma: A Review and Update.

Primary pulmonary B-cell lymphomas (PP-BCLs) comprise a group of extranodal non-Hodgkin lymphomas of B-cell origin, which primarily affect the lung without evidence of extrapulmonary disease at the time of diagnosis and up to 3 months afterwards. Primary lymphoid proliferations of the lung are most often of B-cell lineage, and include three major entities with different clinical, morphological, and molecular features: primary pulmonary marginal zone lymphoma of mucosa-associated lymphoid tissue (PP-MZL, or MALT lymphoma), primary pulmonary diffuse large B cell lymphoma (PP-DLBCL), and lymphomatoid granulomatosis (LYG). Less common entities include primary effusion B-cell lymphoma (PEL) and intravascular large B cell lymphoma (IVLBCL). A proper workup requires a multidisciplinary approach, including radiologists, pneumologists, thoracic surgeons, pathologists, hemato-oncologists, and radiation oncologists, in order to achieve a correct diagnosis and risk assessment. Aim of this review is to analyze and outline the clinical and pathological features of the most frequent PP-BCLs, and to critically analyze the major issues in their diagnosis and management.

Macrophage activating lipopeptide 2 is effective in mycobacterial lung infection.

MALP-2, a synthetic lipopeptide is a Toll-like receptor 2 and -6 ligand and agonist. MALP-2 stimulates immune cells at different sites. Local stimulation in the lungs has beneficial effects in experimental pneumococci infection. The presented study investigated local effects of MALP-2 in the mycobacterial infection of lungs. MALP-2 was applied prior, simultaneously or after the pulmonary infection with Mycobacterium bovis BCG. Colony forming units were determined in the bronchoalveolar lavage fluid and lung homogenate. Numbers of Mycobacterium bovis BCG colony forming units were found to be reduced in two compartments, bronchoalveolar lavage fluid and lung homogenate after treatment with MALP-2 simultaneously to the infection for up to eight weeks. Reduction of the bacterial load in both compartments was also found up to two weeks after local treatment before and after the infection. Thus, macrophage activating lipopeptide-2 enhances the host defence in the lung in acute and long term bacterial infections.

Combating COVID-19: MVA Vector Vaccines Applied to the Respiratory Tract as Promising Approach Toward Protective Immunity in the Lung.

The lung is the vital target organ of coronavirus disease 2019 (COVID-19) caused by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In the majority of patients the most active virus replication seems to be found in the upper respiratory tract, severe cases however suffer from SARS-like disease associated with virus replication in lung tissues. Due to the current lack of suitable anti-viral drugs the induction of protective immunity such as neutralizing antibodies in the lung is the key aim of the only alternative approach-the development and application of SARS-CoV-2 vaccines. However, past experience from experimental animals, livestock, and humans showed that induction of immunity in the lung is limited following application of vaccines at peripheral sides such as skin or muscles. Based on several considerations we therefore propose here to consider the application of a Modified Vaccinia virus Ankara (MVA)-based vaccine to mucosal surfaces of the respiratory tract as a favorable approach to combat COVID-19.

The distributive and structural characteristics of bronchus-associated lymphoid tissue (BALT) in Bactrian camels (Camelus bactrianus).

BACKGROUND: Bronchus-associated lymphoid tissue (BALT), distributed in the bronchial mucosa, plays a critical role in maintaining the mucosal immune homeostasis of the lower respiratory tract. The bronchial tree is a functional structure for gas exchange with the outside environment and maintains basic lung morphology. METHODS: To explore the structural and distributive characteristics of BALT in Bactrian camels, twelve healthy adult Bactrian camels were divided into two groups (six in each group). The lungs, bronchial tree and BALT were observed and analysed systematically through anatomical and histological methods. RESULTS: The results showed that Bactrian camel lungs were constituted by the left cranial lobe, left caudal lobe, right cranial lobe, right caudal lobe and accessory lobe, but lacked the middle lobe. The cranial lobe was narrow and small, the caudal lobe was extremely developed (almost four times the cranial lobe in size), and the accessory lobe was smaller than the cranial lobe; the bronchial tree, an unequal dichotomy with a tracheobronchial branch, was composed of dorsal, ventral, lateral and medial bronchiole systems. Isolated lymphoid follicles (the chief type) and aggregates of lymphoid follicles revealed two types of BALT, and germinal centres, follicle-associated epithelium and high endothelial venules could be observed in some well-developed BALT. Additionally, BALT was scattered along the bronchial tree in the entire lung, and the density increased from the trachea to the lower graded branches (densest in the bronchioles) and then decreased, with the occasional location around respiratory bronchioles or among the pulmonary mesenchyme. In the conducting portion, BALT was primarily located in the mucosa lamina propria but was also found in the submucosa, under the muscular layer, and around the submucosal glands and cartilage. CONCLUSION: The results demonstrated that the lung morphology of Bactrian camels was similar to that of horses, but the bronchial branches were more closely related to those of ruminants. These characteristics were in accordance with the morphological and structural variation regularity of lungs with species evolution. BALT was mainly scattered in the conducting portion, and bronchioles, as the final "checkpoint" in the surveillance, capture and recognition of antigens before pulmonary exchange, were the pivotal locational position of BALT. However, BALT at different depths of the bronchial wall of the conducting portion might be at different developmental stages. Our study provided evidence for further insight into the mucosal immunomodulatory mechanism of BALT in the respiratory system of Bactrian camels.

Isolated aggregates of lymphoid cells in the inner bronchial wall in asthma patients.

Here, we report findings in volunteers with bronchial asthma. Biopsies were obtained from the inner bronchial wall before and a short time again after segmental allergen provocation. In most of the baseline biopsies and in all evaluable biopsies after segmental allergen provocation, the follicular lymphoid tissue was detected by immunohistochemistry in the epithelium of these asthmatic patients. The basic occurrence of the tertiary lymphoid tissue in the bronchial mucosa of mild asthmatics was unexpected and may have consequences for the interpretation of pathophysiology, e.g., as a cause or consequence of bronchial asthma.

Synchronous Pulmonary Neoplasms: A Chance Occurrence or is There More Than Meets the Eye?

Primary bronchus-associated lymphoid tissue (BALT) lymphoma comprises 5% of non-Hodgkin's lymphoma (NHL) and usually has an indolent course. Synchronous primary lung cancers with BALT lymphoma are seldom seen in patients with adenocarcinoma of the lung. Synchronous squamous cell carcinoma (SCC) and BALT lymphoma is an extremely rare occurrence. We report an unusual case of stage 4 BALT lymphoma requiring treatment that revealed an underlying ipsilateral mass causing a diagnostic dilemma. An 84-year-old female with a history of systemic lupus erythematosus, deep vein thrombosis, and thrombotic microangiopathy presented to the hospital with cough and dyspnea on exertion. A chest X-ray revealed right hemi-thorax opacification and computed tomography (CT) of the chest showed a large right effusion and a soft tissue density extending into the proximal right bronchus. She required repeated thoracentesis until the pleural fluid analysis showed the presence of small lymphocytes and bronchial washings revealed an abnormal B cell population consistent with extranodal marginal zone lymphoma. The patient received four cycles of bendamustine and rituximab resulting in near-complete resolution of the effusion. Four months from diagnosis, imaging showed an increase in the size of the soft tissue density with pathologic fluorodeoxyglucose (FDG) uptake on positron emission tomography (PET). A CT-guided biopsy was consistent with squamous cell lung cancer (SCLC) and radiotherapy was started for clinical stage 2 disease since the patient was not a surgical candidate. BALT lymphoma is a low-grade malignancy classified as extranodal marginal zone lymphoma with a five-year survival rate of over 80%. Several cases of synchronous lung adenocarcinoma and BALT lymphoma have been described. However, our case is among the rare few cases of synchronous occurrence of SCLC with BALT lymphoma. This report highlights the challenges associated with establishing an accurate and timely diagnosis.

Manifold Roles of CCR7 and Its Ligands in the Induction and Maintenance of Bronchus-Associated Lymphoid Tissue.

The processes underlying the development and maintenance of tertiary lymphoid organs are incompletely understood. Using a Ccr7 knockout/knockin approach, we show that spontaneous bronchus-associated lymphoid tissue (BALT) formation can be caused by CCR7-mediated migration defects of dendritic cells (DCs) in the lung. Plt/plt mice that lack the CCR7 ligands CCL19 and CCL21-serine do not form BALT spontaneously because lung-expressed CCL21-leucine presumably suffices to maintain steady-state DC egress. However, plt/plt mice are highly susceptible to modified vaccinia virus infection, showing enhanced recruitment of immune cells as well as alterations in CCR7-ligand-mediated lymphocyte egress from the lungs, leading to dramatically enhanced BALT. Furthermore, we identify two independent BALT homing routes for blood-derived lymphocytes. One is HEV mediated and depends on CCR7 and L-selectin, while the second route is via the lung parenchyma and is independent of these molecules. Together, these data provide insights into CCR7/CCR7-ligand-orchestrated aspects in BALT formation.

Application of light sheet microscopy for qualitative and quantitative analysis of bronchus-associated lymphoid tissue in mice.

Bronchus-associated lymphoid tissue (BALT) develops at unpredictable locations around lung bronchi following pulmonary inflammation. The formation and composition of BALT have primarily been investigated by immunohistology that, due to the size of the invested organ, is usually restricted to a limited number of histological sections. To assess the entire BALT of the lung, other approaches are urgently needed. Here, we introduce a novel light sheet microscopy-based approach for assessing lymphoid tissue in the lung. Using antibody staining of whole lung lobes and optical clearing by organic solvents, we present a method that allows in-depth visualization of the entire bronchial tree, the lymphatic vasculature and the immune cell composition of the induced BALT. Furthermore, three-dimensional analysis of the entire lung allows the qualitative and quantitative enumeration of the induced BALT. Using this approach, we show that a single intranasal application of the replication-deficient poxvirus MVA induces BALT that constitutes up to 8% of the entire lung volume in mice deficient in CCR7, in contrast to wild type mice (WT). Furthermore, BALT induced by heat-inactivated E. coli is dominated by a pronounced T cell infiltration in Cxcr5-deficient mice, in contrast to WT mice.