Anti-Mouse CD62L [Clone MEL-14] — Purified in vivo GOLD™ Functional Grade

Clone MEL-14, a rat monoclonal antibody targeting mouse CD62L (L-selectin), has two primary in vivo applications in mouse research models.

Functional Blockade of Lymphocyte Homing

The most prominent in vivo application of MEL-14 is blocking lymphocyte trafficking to lymph nodes. Pre-incubation of lymphocytes with MEL-14 completely and specifically blocks the binding of lymphocytes to high endothelial venules (HEV) in vitro and prevents the migration of lymphocytes to lymph nodes in vivo. This functional blocking capability makes MEL-14 valuable for investigating lymphocyte extravasation and homing mechanisms. The antibody inhibits in vivo lymphocyte extravasation into peripheral lymph nodes by interfering with CD62L's role as a "homing receptor" for lymphocytes entering secondary lymphoid tissues via high endothelial venules.

Flow Cytometric Identification of Lymphocyte Subpopulations

MEL-14 serves as a surface marker for identifying and characterizing lymphocyte subsets in vivo studies. Since CD62L is expressed on the majority of naïve T and B cells, a subset of memory T cells, monocytes, neutrophils, granulocytes, NK cells, and most thymocytes, MEL-14 allows researchers to distinguish between different lymphocyte populations based on their CD62L expression patterns. This is particularly useful for differentiating naïve from memory T cells, as CD62L expression levels vary between these subsets.

The antibody is available in multiple formats specifically designed for in vivo use, including purified functional grade formulations with low endotoxin content to ensure compatibility with live animal studies.

Commonly used antibodies or proteins that are frequently reported in the literature alongside MEL-14 (anti-mouse CD62L/L-selectin) include markers for T and B cell subsets, activation markers, adhesion molecules, and trafficking markers.

Key antibodies and proteins often used with MEL-14 are:

• CD3 (pan-T cell marker)
• CD4 (helper T cell marker)
• CD8 (cytotoxic T cell marker)
• CD19 or B220 (B cell markers)
• CD44 (activation/trafficking marker)
• CD45RA/CD45RB (T cell naive/memory subset markers)
• CD25 (activation marker)
• CD69 (early activation marker)
• CD62P (P-Selectin) and CD62E (E-Selectin) (other selectin family adhesion molecules)
• Chemokine receptors such as CCR7 (homing/trafficking marker)
• Integrins like LFA-1 (CD11a/CD18) and VLA-4 (CD49d/CD29) (adhesion/activation)

These combinations are critical in studies focused on lymphocyte characterization, trafficking, homing, and activation status. For example, using MEL-14 with antibodies against CD44 and CCR7 permits discrimination between naïve, central memory, and effector memory T cell subsets by flow cytometry or immunofluorescence. In addition, experiments may combine MEL-14 with markers to identify functional changes following activation or trafficking inhibition.

MEL-14 is also routinely used in panels for flow cytometry with surface markers and other adhesion molecules to evaluate lymphocyte migration and immune status.

The MEL-14 monoclonal antibody is a significant tool in immunological research, notably for its specificity to the murine homing receptor, which is later identified as CD62L (L-Selectin). Key findings from scientific literature citing clone MEL-14 include:

1. Recognition of the Lectin Domain: MEL-14 initially was characterized for binding to the lectin domain of the murine peripheral lymph node homing receptor. It blocks the binding of murine lymphocytes to endothelial cells in peripheral lymph nodes, both in vitro and in vivo.

2. Dependency on Domain Structure: The recognition by MEL-14 is dependent on the NH2-terminal portion of the lectin domain, and its conformation may require the presence of the EGF-like domain for optimal recognition.

3. Involvement in Lymphocyte Homing: MEL-14 is involved in studying lymphocyte homing to lymph nodes, as it inhibits the interaction between lymphocytes and the high endothelial venules (HEV) in peripheral lymph nodes.

4. CD62L (L-Selectin) Specificity: MEL-14 specifically binds to CD62L, a glycoprotein expressed on leukocytes, including neutrophils and lymphocytes, and is used as a marker to distinguish naive and memory T cells from effector T cells.

5. Applications in Research: The antibody has been widely used for cell subset identification and in studies related to inflammation and immune responses, particularly involving neutrophil extravasation.

Dosing regimens for clone MEL-14, a monoclonal antibody against mouse CD62L (L-selectin), can vary depending on the specific application and mouse model used in research. Here are some general considerations and guidelines:

General Considerations

• Lymphocyte Homing Inhibition: MEL-14 blocks the binding of lymphocytes to high endothelial venules (HEVs) and inhibits lymphocyte migration to lymph nodes, which is crucial for studies involving immune cell trafficking and homing.
• Dosing for Functional Assays: In functional assays, the amount of MEL-14 used can vary, but it is often necessary to remove sodium azide, which is commonly used as a preservative, to ensure the antibody remains active.
• Flow Cytometry: For staining cells in flow cytometry, a concentration of ≤ 0.25 μg per 10^6 cells in a volume of 100 μl is suggested.

Specific Mouse Models

• Inflammation Models: In models of inflammation, such as delayed-type hypersensitivity (DTH) models, MEL-14 can be used to block naive T cell recruitment, reducing inflammation markers like ear swelling.
• Immune System Studies: In studies focusing on immune cell behavior, MEL-14 can be administered systemically to block lymphocyte homing, which might require dosing similar to that used in functional assays to ensure efficacy.

Variability in Dosing Regimens

• Route of Administration: Typically not detailed for MEL-14, but intravenous or intraperitoneal routes are common for similar antibodies.
• Dose Range: Specific dose ranges for MEL-14 in different models are not well-documented, but generally, antibodies are used in the range of micrograms per mouse, similar to other monoclonal antibodies.
• Optimal Dosing Schedule: The schedule would depend on the experimental design and the desired effect, such as continuous blockade or intermittent exposure.

For precise dosing information in specific mouse models, researchers typically consult the literature or perform pilot studies to determine the optimal dose and administration schedule.