Anti-Mouse CD11a (Clone FD441.8) – Purified in vivo PLATINUM™ Functional Grade

Clone FD441.8 is a rat monoclonal antibody that targets mouse CD11a (also known as LFA-1α). It is commonly used in in vivo applications in mice for the following purposes:

1. LFA-1 Neutralization: Clone FD441.8 is used to block or inhibit the function of LFA-1, which plays a crucial role in intercellular adhesion, leukocyte-endothelial cell interaction, and cytotoxic T-cell mediated killing. This is particularly useful in studies involving immune response and cell interactions.

2. Flow Cytometry: Although not the primary application in vivo, it is suitable for flow cytometry (FC) when used in conjunction with other in vivo assays.

3. Functional Assays: The antibody is used in functional assays to inhibit or block LFA-1 activity, which helps in studying its role in immune phenomena such as leukocyte adhesion and migration.

4. Immunological Studies: By blocking LFA-1α, researchers can study its impact on various immunological processes, including T-cell interactions and immune cell trafficking.

In summary, Clone FD441.8 is primarily used for LFA-1 neutralization in in vivo studies, facilitating the investigation of immune functions and cell adhesion processes in mice.

Commonly Used Antibodies and Proteins with FD441.8 in the Literature

Anti-CD11a (FD441.8) is a rat monoclonal antibody specific for mouse CD11a (LFA-1α, also known as integrin alpha-L), a key component of the LFA-1 integrin complex involved in leukocyte adhesion and migration. In published research, FD441.8 is frequently used alongside other antibodies and proteins to study immune cell interactions, adhesion, and trafficking. Here are some of the most commonly co-used reagents and their specific roles:

Blocking, Functional, and Isotype Controls

• Purified Rat IgG2b, κ Isotype Control (LTF-2): Often used as a negative control to ensure the specificity of FD441.8 in flow cytometry and functional assays.
• Functional Blocking: FD441.8 itself is used for blocking LFA-1 interactions, for example, to study the role of LFA-1 in leukocyte adhesion or migration.
• Preclinical Functional Grade Antibodies: These are designed for in vitro and in vivo studies, ensuring minimal endotoxin and protein contamination for immune modulation experiments.

Co-Used Monoclonal Antibodies for Costimulation Blockade

In the context of immune response modulation, especially in transplant and autoimmune research, FD441.8 (anti-mouse CD11a) is often paired with antibodies targeting costimulatory molecules to achieve synergistic immunosuppression:

• Monoclonal Antibodies Against CD154 (e.g., MR-1): In studies of transplant tolerance and islet xenograft survival, FD441.8 has been used together with anti-CD154 (MR-1) to provide dual blockade of LFA-1 and CD40-CD154 pathways, significantly extending graft survival in mouse models. This combination targets both the antigen-independent and antigen-dependent pathways of T cell activation.
• Other Integrin Blockers: While FD441.8 targets CD11a (α chain of LFA-1), complementary antibodies against the CD18 (β chain) are sometimes used to fully block LFA-1 function, though these are less frequently cited together with FD441.8 in the provided literature.

Antibody Panels for Flow Cytometry and Immunophenotyping

FD441.8 is often included in multi-color flow cytometry panels to identify and characterize immune cell subsets. While the specific combinations vary by experiment, common co-stains might include:

• Anti-CD3, Anti-CD4, Anti-CD8: For T cell subset identification.
• Anti-B220, Anti-CD19: For B cell identification.
• Anti-CD44, Anti-CD62L: For memory/naïve T cell discrimination.
• Anti-Mac-1 (CD11b): For myeloid lineage cells, sometimes analyzed alongside CD11a to distinguish leukocyte subsets.
• Anti-α4β7 (DATK32), Anti-MAdCAM-1 (MECA-367): For studying gut-tropic lymphocytes and mucosal homing.

Functional Assays and Cell Migration Studies

• Blocking Adhesion Molecules: In studies of leukocyte trafficking, FD441.8 is used to block LFA-1, while antibodies against P-selectin, MAdCAM-1, or other adhesion molecules may be used to dissect the contributions of different pathways.
• In Vivo Models: For in vivo functional studies, FD441.8 is sometimes administered systemically, alone or in combination with other blocking antibodies, to assess the role of LFA-1 in disease models.

Summary Table: Key Antibodies and Proteins Used with FD441.8

Typical Experimental Contexts

• Transplant Models: FD441.8 + anti-CD154 for costimulation blockade.
• Flow Cytometry: FD441.8 in multi-color panels with lineage and activation markers.
• Adhesion/Migration: FD441.8 combined with blockers of other adhesion molecules (e.g., P-selectin, MAdCAM-1) to dissect leukocyte trafficking mechanisms.
• In Vivo Functional Studies: FD441.8 alone or with other functional grade antibodies for immune modulation.

Conclusion

FD441.8 is most commonly used with antibodies targeting costimulatory molecules (especially CD154), isotype controls, and a range of cell lineage markers for comprehensive immunophenotyping. Its use in blocking studies often involves complementary adhesion molecule blockers to dissect complex leukocyte trafficking pathways. The specific combination depends on the experimental question, but these pairings are well established in the immunology literature.

Key Scientific Findings Involving Clone FD441.8

FD441.8 is a rat monoclonal antibody (rat IgG2b isotype) specifically recognizing mouse CD11a (LFA-1α), a subunit of the LFA-1 (Lymphocyte Function-Associated Antigen-1) integrin that mediates leukocyte adhesion and immune synapse formation. It is widely used in immunological research for blocking LFA-1 function, flow cytometry, and related applications.

Below are the key findings and applications from the scientific literature citing clone FD441.8:

Functional Studies

• LFA-1 Blockade: FD441.8 is well-characterized as a blocking antibody that inhibits LFA-1-mediated cellular adhesion. Its application has been shown to block ConA-facilitated lysis but does not affect PHA-facilitated lysis, highlighting specific context-dependent effects of LFA-1 blockade.
• Immune Synapse Inhibition: FD441.8 has been used to demonstrate that LFA-1 is critical for the formation of immunological synapses between CD8+ T lymphocytes and antigen-presenting cells, a fundamental process in adaptive immunity.
• Blockade of Antigen Presentation: In co-culture studies, FD441.8 specifically blocked antigen presentation by cells expressing ICAM-1 (the ligand for LFA-1), but not by cells lacking ICAM-1 expression, underlining the importance of LFA-1/ICAM-1 interaction for efficient T cell activation.
• Naive B Cell Trafficking: FD441.8 has been employed to show that local chemokine availability directs naive B cell trafficking, and blockade of LFA-1 with this antibody modulates such trafficking, indicating a crucial role for LFA-1 in lymph node homing and immune surveillance.
• Graft Infiltration Inhibition: In transplantation models, administration of FD441.8 was shown to inhibit early infiltration of endogenous leukocytes into allografts, suggesting therapeutic potential for LFA-1 blockade in reducing graft rejection.

Technical and Preclinical Applications

• Antibody Specifications: FD441.8 is produced with very low endotoxin levels—making it suitable for in vivo functional studies—and is available as “purified” as well as “functional grade” for a range of applications including immunohistochemistry, immunoprecipitation, and more.
• In Vivo Use: The antibody is validated for in vivo administration, where it can effectively inhibit LFA-1-dependent immune processes in mouse models.
• Pharmaceutical-Grade Production: Manufacturers like Leinco Technologies produce animal-free, low-endotoxin versions of FD441.8, expanding its utility in preclinical research.

Summary Table: Major Biological Effects of FD441.8-Mediated LFA-1 Blockade

Conclusion

Clone FD441.8 is a pivotal tool for dissecting LFA-1 (CD11a) function in murine immunology, with a strong track record in blocking leukocyte adhesion, immune synapse formation, and modulating lymphocyte trafficking. Its specific, functional blockade has provided direct evidence for the critical role of LFA-1 in immune responses, antigen presentation, and transplant rejection, and it remains widely used in both basic and translational research.

Dosing Regimens of clone FD441.8 (Anti-LFA-1) in Different Mouse Models

Clone FD441.8 is a monoclonal antibody targeting LFA-1 (CD11a/CD18), commonly used in mouse models to study immune responses, particularly in transplantation, inflammation, and immune cell trafficking research.

Experimental Transplant Model

In a cardiac allograft model, mice (C57BL/6 and A/J strains) received intraperitoneal injections of anti-LFA-1 mAb (clone FD441.8) at 0.2 mg (200 μg) per mouse on days –1 and 0, or days +3 and +4 post-transplant. This schedule was designed to transiently block LFA-1 during critical early phases of alloantigen recognition and graft rejection. Notably, this dosing was used alongside other immune-modulating antibodies and was shown to impact alloreactive T-cell responses and graft outcome.

Xenotransplantation/Pancreatic Tissue Model

In a pig-to-mouse pancreatic tissue transplantation study, dosing of anti-LFA-1 (clone FD441.8, from the same source and presumably the same preparation) was given intraperitoneally (i.p.) at 200 μg/mouse on days 0, 2, 4, and 6 post-transplant, with a single injection repeated biweekly until 3 months post-transplant. This regimen was part of a broader immune suppression protocol and aimed for sustained LFA-1 blockade to promote engraftment and prevent graft rejection.

Comparison Table

Key Observations

• Total dose per injection remains consistent at 200 μg/mouse across both studies, but the dosing schedule varies depending on the experimental endpoints and model requirements.
• Administration route is universally intraperitoneal (i.p.), which is standard for in vivo antibody delivery in mouse models.
• Timing of administration is tailored to the biological question: acute blockade for allograft models (just before and after transplant), versus prolonged/repeated dosing for xenograft studies to maintain immunosuppression.
• Combinatorial therapy is common; anti-LFA-1 is rarely used alone and is typically part of multi-agent immunosuppressive regimens.

Practical Considerations

• Antibody preparation and source are critical; both cited studies used clone FD441.8 from Bio Express (now Bio X Cell), ensuring reagent consistency.
• Mouse strain and age do not appear to affect the primary dosing regimen, as both C57BL/6 (commonly used in transplantation) and other strains were treated with the same dose.
• No reports were found for significantly higher or lower doses in other published mouse models, suggesting 200 μg/mouse i.p. is a robust, empirically validated reference dose for FD441.8 in mice.

Summary

The dosing regimen for clone FD441.8 (anti-LFA-1) in mouse models is 200 μg per mouse, intraperitoneally, but the frequency and duration of administration vary according to the experimental model and desired outcome—acute dosing for short-term immune blockade or repeated dosing for sustained suppression. This flexibility allows researchers to tailor the regimen to the specific biological processes under investigation, while the per-dose amount remains consistent across published protocols.