Lung macrophages are a key component of the mononuclear phagocyte system, residing within the respiratory tract where they serve as the first line of immune defense. These cells originate from two major sources:
- Bone marrow–derived monocytes, which migrate into the lungs and differentiate into macrophages, and
- Resident macrophages, such as alveolar macrophages (AMs) that self-renew locally.
Within the lung, macrophages can be broadly categorized into two populations:
- Alveolar Macrophages (AMs) – located in the alveolar spaces, maintaining homeostasis and clearing inhaled particles.
- Interstitial Macrophages (IMs) – distributed within the lung interstitium, contributing to immune regulation and tissue remodeling.
Functional Roles of Lung Macrophages
Lung macrophages play multifaceted roles essential for respiratory immune balance and tissue integrity:
- Immune Surveillance: Constantly monitor inhaled particles, pathogens, and cellular debris to maintain pulmonary defense.
- Phagocytosis: Remove pathogens, dead cells, and dust through engulfment and degradation.
- Inflammatory Response: Upon infection or injury, they secrete cytokines and chemokines to recruit other immune cells.
- Tissue Repair: Promote wound healing and tissue remodeling during the resolution phase of inflammation.
- Antigen Presentation: Process and present antigens to T cells, bridging innate and adaptive immunity.
- Metabolic Regulation: Participate in local lipid and iron metabolism to maintain homeostasis.
Depletion of Lung Macrophages Using Clodronate Liposomes
Following our previous lesson on hepatic macrophage depletion, this article summarizes several published studies demonstrating effective strategies for selective removal of pulmonary macrophages using Clodronate Liposomes in mice.
Case 1
Reference: Murine Alveolar Macrophages Limit Replication of Vaccinia Virus
Method: Intratracheal injection of 100 µL Clodronate Liposomes.
Results:
Total recovered cell numbers in bronchoalveolar lavage fluid (BALF) were quantified at various timepoints (n = 3 per group). Results were expressed as the percentage of recovered cells relative to untreated or control liposome–treated mice, showing significant macrophage depletion 24 hours post-injection.
Case 2
Reference: Alveolar Macrophages Are Sentinels of Murine Pulmonary Homeostasis Following Inhaled Antigen Challenge
Method: Intratracheal administration of 50 µL Clodronate Liposomes once weekly.
Results:
Flow cytometry analysis at days 1, 4, and 7 post-administration confirmed effective depletion and gradual recovery of alveolar macrophages, illustrating the time-dependent clearance dynamics.
Case 3
Reference: Respiratory Macrophages Regulate CD4 T Memory Responses to Mucosal Immunization with Recombinant Adenovirus-Based Vaccines
Method: Intraperitoneal injection of 2 mg Clodronate Liposomes per 20 g mouse.
Results:
Flow cytometry of spleen and lung tissues demonstrated reduced expression of CD11c and F4/80 markers, indicating systemic macrophage depletion, including pulmonary populations.
Case 4
Reference: CD11c+/CD11b+ Cells Are Critical for Organic Dust–Elicited Murine Lung Inflammation
Method: Intranasal injection of 30 µL Clodronate Liposomes, administered every 3–4 days over three weeks.
Results:
Sustained dosing effectively maintained macrophage depletion and reduced lung inflammatory responses to organic dust exposure.
Tips:
- Experimental conditions such as mouse strain, infection model, and liposome type may vary, so the above dosing information is for reference only.
- Adjust injection routes and volumes based on your study design and review related literature before starting experiments.
- Different tissues may require different administration methods for effective macrophage depletion.
- Yeasen Biotech will continue to share organ-specific protocols — let us know your research focus or questions, and our technical team will be glad to help.
In the next chapter of our Macrophage Clearance Classroom, we’ll continue exploring organ-specific applications and share practical guidance on evaluating macrophage depletion efficiency.
Empower your immunology research — with Yeasen Clodronate Liposomes, the trusted choice for reliable and reproducible macrophage depletion.
Related Product
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Name |
Cat. No. |
Size |
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40337ES08/10 |
5 mL/10 mL |
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40338ES08/10 |
5 mL/10 mL |