Anti-Mouse NK1.1 [Clone PK136] — Purified in vivo PLATINUM™ Functional Grade

Clone PK136 is primarily used in vivo for the depletion of natural killer (NK) cells in mice to study their roles in immunity, cancer, and infection. Beyond NK cell depletion, it is also utilized for blocking/neutralizing NK1.1 function, flow cytometry, and functional assays.

Key in vivo applications include:

• NK Cell Depletion: The most common use of PK136 involves intraperitoneal injection to selectively deplete NK cells, enabling researchers to assess NK cell contributions in models of immunology, tumor biology, infectious diseases, and autoimmune processes.

• Block/Neutralize/Inhibit NK1.1: The antibody is used to block NK1.1-mediated signaling or function in vivo, helping dissect the role of NK1.1+ cells, including subsets of NK and NKT cells, in various physiological and pathological contexts.

• Functional/Activity Assays: PK136 can facilitate activation or inhibition of NK cells depending on the experimental setup, such as redirected lysis or in vitro/in vivo activation protocols.

• Strain-Specific Studies: PK136 targets NK1.1 (CD161b/CD161c), which is expressed on NK cells and a subset of T cells in certain mouse strains such as C57BL/6, FVB/N, NZB, but not on strains like BALB/c or SJL. Appropriate strain selection is crucial for in vivo use.

• Additional Immunological Studies: PK136 can serve in immunophenotyping, tracking, or depleting NK1.1+ cells to explore immune cell subset functionality.

Summary Table of Common In Vivo Applications of PK136 in Mice

In summary, PK136’s most common in vivo use is for targeted depletion of NK cells, with additional applications in blocking, phenotyping, and functional studies in mouse models where NK1.1 is expressed. Proper mouse strain selection is essential for effective use.

Commonly used antibodies or proteins used alongside PK136 in the literature include anti-CD3ε, anti-CD49b (DX5), and anti-Asialo GM1 for mouse natural killer (NK) cell identification and depletion studies. These antibodies are frequently chosen due to their ability to complement PK136, facilitating the distinction or functional manipulation of NK cells in various settings.

Essential context and supporting details:

• Anti-CD3ε: Used to exclude T cells from analysis or to study T and NK cell interactions.
• Anti-CD49b (DX5): A widely used marker for mouse NK cells, especially important for identifying NK cells in mouse strains that do not express NK1.1. Simultaneous staining with PK136 and DX5 is common to ensure accurate detection.
• Anti-Asialo GM1: Often employed to complement PK136 for NK cell depletion; it targets a different glycolipid on NK cells and allows for depletion in strains or experimental settings where PK136 is less effective or applicable.

Additional relevant antibodies and controls:

• Protein-G purified mouse IgG2a (clone 5D11): Used as an isotype control in depletion experiments with PK136.
• Anti-NKp46 (clone 29A1.4): Sometimes used as an alternative NK cell marker, particularly in multi-species or specific functional studies.
• Strain controls and alternative markers: Certain antibodies are only effective in particular mouse strains (e.g., PK136 is not reactive in BALB/c mice, where DX5 is preferred).

These combinations optimize identification, depletion, or functional manipulation of NK cells for in vivo and in vitro studies across different experimental contexts and mouse strains.

Clone PK136 is a monoclonal antibody widely cited in scientific literature for its high specificity to the mouse NK1.1 antigen, a cell surface marker primarily found on natural killer (NK) cells and certain T cell subsets. The key findings from studies using clone PK136 are as follows:

• Highly Specific NK1.1 Detection: PK136 binds specifically and with high affinity to NK1.1 (CD161/NKR-P1C), enabling reliable identification and sorting of NK1.1+ cells in mouse strains that express this marker (such as C57BL/6, FVB/N, CE, NZB).
• Efficient NK Cell Depletion: Treatment with PK136 is a widely used method to deplete NK cells in vivo, which has facilitated key studies in immunology by allowing researchers to investigate the role of NK cells in tumor models, infections, and autoimmunity. It is noted for:
  • High efficiency in depleting NK cells when appropriately titrated.
  • The ability to use both single and multiple dosing regimens depending on experimental needs.
• Utility Across Experimental Models: PK136 is employed in various applications, including flow cytometry, immunoprecipitation, immunohistochemistry, immunofluorescence, and direct in vivo NK cell depletion.
• Functional Insights Into NK Cells: Use of PK136 has enabled discoveries such as:
  • Improved anti-tumor immunity: Depletion of NK1.1+ cells can enhance the rejection of established melanoma in certain adoptive cell therapy models.
  • Behavioral neuroscience: Removal of CD3−/NK1.1+ cells via PK136 affects anxiety-like behaviors in mice, linking innate immune cells to neurobehavioral processes.
  • Immune cell differentiation: The antibody has been critical in distinguishing developmental pathways and functions of murine NK cells.
• Limitations and Considerations:
  • Strain restriction: NK1.1 is not universally expressed on NK cells across all mouse strains (notably absent in BALB/c, 129, C3H, SJL, and others).
  • Potential off-target effects and immune responses: While PK136 is highly specific, non-specific binding and immune response to the antibody can occur with repeated administration.
  • Variable depletion efficacy: The efficiency of NK cell depletion can vary between experiments and strains, necessitating optimization for dose and schedule.

In sum, PK136 is foundational for studying NK cell biology in vivo in NK1.1-expressing mouse strains, with findings broadly supporting its specificity, efficiency for cell identification and depletion, and critical role in advancing our understanding of NK cell function in immunity and disease.

Dosing regimens of the anti-NK1.1 antibody clone PK136 vary across mouse models primarily by dose, frequency, and duration, depending largely on the mouse strain and experimental goals.

• For C57BL/6 and related NK1.1+ strains:

  • Typical single dose: 200–300 μg per mouse, administered intraperitoneally.
  • Repeated dosing: 200 μg per mouse every 3–5 days for sustained NK cell depletion.
  • Higher initial dose protocol: 250 μg per mouse as the first dose, then maintenance doses of 100–150 μg every 3–5 days.
  • Extended depletion: Up to 500 μg (0.5 mg) per mouse, three times per week, has been used for prolonged depletion, including depletion of both NK1.1+ and NK1.1+ T cells.

• Dosing schedule considerations:

  • Frequency may be 1–3 times per week, tailored to ensure continued NK cell loss throughout the experiment.
  • Dose optimization often requires preliminary experiments to account for variation by mouse strain, age, and research endpoint.
  • Some regimens note decreased efficacy or immune responses with long-term repeated dosing due to potential antibody clearance or anti-mouse antibody generation.

• Mouse strain limitations:

  • NK1.1 is predominantly expressed in C57BL/6 and some related strains, limiting PK136 utility to these models; other strains may not express the targeted antigen, rendering the antibody ineffective.

• Efficacy:

  • A single administration can reduce splenic NK1.1+ cells from around 5.5% to 0.6% in C57BL/6 mice.
  • Up to 80% depletion of liver NK1.1+ T cells has been reported after one week of 0.5 mg dosing three times per week.

Key variables impacting regimen selection:

• Strain specificity: PK136 is effective only in NK1.1+ mouse strains, not all laboratory mice.
• Experimental endpoint: Acute studies may use a single dose, while chronic studies use repeated injections.
• Age and immune status: Younger or immunodeficient mice may have altered antibody pharmacokinetics or responses.

In summary, PK136 dosing in mouse models often involves intraperitoneal injection of 200–500 μg per mouse per dose, singly or on a repeated schedule, with optimization based on mouse genetics and experimental design.