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

Clone FD441.8 is a rat monoclonal antibody targeting mouse CD11a (LFA-1α) and is widely used in vivo to functionally block or deplete LFA-1 activity, most commonly to inhibit leukocyte adhesion, migration, and T cell activation in murine models.

Key in vivo applications in mice include:

• Blocking LFA-1 (CD11a)-mediated leukocyte adhesion and trafficking: FD441.8 inhibits the interaction between LFA-1 and its ligands (ICAM-1, ICAM-2) to prevent leukocyte adhesion to vascular endothelium, thus impairing tissue infiltration during inflammation or immune responses.
• Impairment of T cell–APC (antigen-presenting cell) interactions: LFA-1 is essential for immune synapse formation between T cells and APCs. Blocking CD11a with FD441.8 can dampen T cell activation and cytotoxicity in vivo, offering insight into immune regulation mechanisms.
• Inhibition of dendritic cell and other leukocyte migration: Functional blockade of LFA-1 can be used to study the requirement for integrin-mediated motility of dendritic cells and other immune cell subsets in models of infection, autoimmunity, and cancer.
• Prevention or modulation of graft-versus-host disease and autoimmune conditions: By limiting lymphocyte infiltration into tissues, FD441.8 enables studies of immune-mediated tissue damage and therapeutic strategies in transplant and autoimmune models.

Additional standard uses:

• In vivo depletion or blockade protocols for functional immune studies: FD441.8 is routinely used as a blocking antibody in vivo for functional analysis of the CD11a pathway, with recommended low endotoxin preparations for animal injections.
• Controls for mechanistic studies in inflammation and immunology research.

Less common or indirect applications:

• Allograft and transplant rejection studies: Modulating T cell infiltration to allografts.
• Tumor immunology: Modulating antitumor T cell responses, especially cytotoxic T lymphocyte recruitment.

Experimental considerations: Successful use in vivo depends on optimizing dose, timing, and route of administration for each experimental design, and using functionally validated, low-endotoxin antibody preparations.

Summary Table: Common In Vivo Applications of Clone FD441.8 in Mice

Note: While clone FD441.8 is validated for in vivo functional inhibition, depletion of cells expressing CD11a is not a common or efficient application due to its mode of action as a blocking rather than depleting antibody. For depleting certain leukocyte subsets, depletion-specific clones or toxin-conjugated antibodies are preferable.

References marking the main points:

Based on the search results, FD441.8 (an anti-mouse CD11a/LFA-1α antibody) is commonly used in combination with several other antibodies and proteins in research applications:

Co-stimulation Blockade Studies

FD441.8 is frequently paired with anti-CD154 monoclonal antibodies in co-stimulation blockade protocols. In pancreatic islet xenograft survival studies, researchers used an equal mixture of FD441.8 and MR-1 (an anti-CD154 antibody) to achieve subtherapeutic co-stimulation blockade. This combination targets different aspects of the immune response by blocking both LFA-1-mediated adhesion and CD154-dependent costimulatory signals.

Lymphocyte Function Studies

In lymphocyte homing and trafficking research, FD441.8 has been used alongside other adhesion molecule antibodies including anti-CD4 (clone GK1.5), anti-CD8 (clone 53-6.7.2), and anti-α4 (clone PS/2). This combination allows researchers to comprehensively examine the roles of different integrins and surface markers in lymphocyte migration to specific tissues like bronchus-associated lymphoid tissue.

Natural Pairing with Ligands

Given that FD441.8 targets LFA-1α (CD11a), it naturally functions in systems involving LFA-1's binding partners. The antibody is relevant in studies examining interactions with ICAM-1 (CD54), ICAM-2 (CD102), and ICAM-3 (CD50), which are the natural ligands for LFA-1. Additionally, since CD11a combines with CD18 (integrin beta-2 chain) to form the complete LFA-1 heterodimer, studies may examine both components together.

Clone FD441.8 is a monoclonal antibody that targets mouse CD11a, also known as LFA-1α, which plays a crucial role in cell adhesion and immune responses. Here are the key findings from its citations in scientific literature:

Key Findings

1. Target Specificity: Clone FD441.8 specifically recognizes an epitope on mouse CD11a, an antigen present on thymocytes, blood lymphocytes, bone marrow cells, and certain lymphoma and macrophage-like cell lines.

2. Applications: This antibody is used in various applications, including blocking, immunohistochemistry, immunoprecipitation, and in situ hybridization.

3. Immune Response Modulation: The FD441.8 antibody has been used in studies to modulate immune responses. For example, it has been employed to block LFA-1 interactions, which are critical for leukocyte adhesion and migration.

4. Mechanism of Action: Studies have shown that blocking LFA-1 with FD441.8 can inhibit the early infiltration of endogenous memory T cells, indicating its potential in manipulating immune cell trafficking.

5. Impact on T Cell Functions: The antibody has been used to investigate the role of LFA-1 in T cell adhesion and antigen presentation. It was observed that FD441.8 could block antigen presentation under certain conditions, highlighting the complex role of LFA-1 in immune interactions.

Conclusion

Clone FD441.8 is a valuable tool in immunological research, particularly in studies involving LFA-1 and its role in immune cell adhesion and trafficking. Its applications range from basic research to potential therapeutic interventions, where modulating immune responses is essential.

Dosing regimens of clone FD441.8 (anti-LFA-1) in mouse models typically involve intraperitoneal injections of the antibody at a dose of 250 μg per mouse on specific days post-transplant (days 0, 2, 4, and 6), followed by biweekly injections until 3 months post-transplantation. Most published protocols use this antibody as part of multi-agent immune suppression to enable transplantation success, particularly in strains resistant to xenograft acceptance, such as C57BL/6 mice.

• Standard regimen: 250 μg/mouse intraperitoneally on days 0, 2, 4, and 6, with biweekly boosters up to 3 months.

Regimen variations may depend on:

• Mouse strain and immunological challenge: For example, highly immunocompetent strains like C57BL/6 may require adjunctive immunosuppressants (e.g., FTY720) in addition to anti-LFA-1 for optimal xenograft survival.
• Study aim (transplantation vs. cell labeling/in vitro): In cell labeling or in vitro flow-based assays, FD441.8 may be used at considerably lower concentrations, such as 50 μg/mL for staining at 4°C for 30 minutes. This is not directly comparable to in vivo dosing for functional blockade.

Additional relevant details:

• Injection route is typically intraperitoneal.
• Combined regimens frequently pair FD441.8 with other antibodies (anti-CD48, CTLA4-Ig) or pharmacologic agents (FTY720, rapamycin, FK506, MMF), with dosing and schedule adapted for each component.
• No substantive data is available from search results on varying FD441.8 dosing in tumor versus transplantation or infection models. Most published dosing schedules focus on transplantation and immune tolerance research.

In summary, while FD441.8 dosing in mouse models is usually 250 μg/mouse i.p. given repeatedly over several weeks to months, variations reflect study-specific goals, mouse strain immunogenicity, and combination with other immunosuppressive agents.