Anti-Mouse CD28 [Clone 37.51] — Purified in vivo GOLD™ Functional Grade

Clone 37.51 is most commonly used in vivo in mice to provide CD28-mediated costimulation, which augments T cell activation, proliferation, and cytokine (notably IL-2) production; it is also applied to block CD28 signaling to study immune modulation and tolerance.

Key in vivo applications include:

• T cell costimulation: Administering 37.51 stimulates the CD28 receptor alongside TCR/CD3 stimulation, mimicking physiological costimulatory signals and enhancing T cell expansion, IL-2 secretion, cytotoxicity, and immune responses during immunological studies or disease models.
• Functional immunology studies: 37.51 is widely used to investigate the role of CD28 in T cell development, differentiation, and to study biological pathways involving CD28 in vivo.
• CD28 blockade: The antibody is applied to block costimulatory signals via CD28, which is crucial for experiments on T cell anergy, tolerance induction, transplantation immunology, or autoimmune disease models.
• Antibody-based modulation: Clone 37.51 is also used to selectively engage or inhibit CD28 to dissect its involvement in immune pathologies, including studies of cytotoxic T lymphocyte (CTL) induction and NK cell function.

These applications are supported by the antibody's strong binding specificity for mouse CD28 and its ability to reliably modulate immune responses in vivo as well as in vitro.

The 37.51 antibody targets mouse CD28, a key costimulatory molecule on T cells. In immunological assays and experimental protocols, 37.51 is almost always used alongside other antibodies or proteins that define immune cell populations or modulate T cell activation. Within the literature, some of the most commonly used antibodies or proteins in combination with 37.51 include:

• Anti-CD3 (e.g., clone 145-2C11 or 17A2): Used to provide primary T cell receptor (TCR) stimulation. The combination of anti-CD3 and anti-CD28 (37.51) is classic for T cell activation in vitro and in vivo, as CD3 delivers the first signal (antigen-specific) and CD28 delivers the second (costimulatory) signal.

• CD80 (B7-1) and CD86 (B7-2) Proteins: These are the natural ligands for CD28, often analyzed or blocked in parallel to dissect costimulatory pathways.

• Other lineage and activation markers: Common flow cytometry panels may include:

  • Anti-CD4 and anti-CD8: To discriminate between T cell subsets.
  • Anti-CD25 (IL-2Rα): To mark activated/regulatory T cells.
  • Anti-CD69: An early activation marker.
  • Cytokine antibodies (e.g., anti-IL-2, anti-IFN-γ): For intracellular cytokine staining following stimulation.

• NK cell markers: As CD28 is also expressed on NK cells, studies may include anti-NK1.1 antibodies.

• Isotype controls: Typically, Syrian hamster IgG (matched to 37.51's isotype) are used as negative controls in flow cytometry or functional assays.

Key references from manufacturers and reagent suppliers confirm that applications almost always involve:

• T cell activation assays with anti-CD3 plus 37.51 (anti-CD28) for costimulation
• Functional studies with ligands CD80/CD86 to probe CD28 signaling
• Immunophenotyping panels with markers to identify T cell and NK cell subpopulations

In summary, anti-CD3 is the most frequent partner for 37.51 (anti-CD28), with additional typical antibodies including anti-CD4, anti-CD8, anti-CD25, anti-CD69, and sometimes NK1.1 and cytokine-specific antibodies depending on the experimental context.

The monoclonal antibody clone 37.51 targets the mouse CD28 molecule, a 45 kDa homodimer expressed on thymocytes, mature T cells, and NK cells. CD28 is a potent costimulator of T cells, interacting with CD80 (B7-1) and CD86 (B7-2) to enhance T cell activation and cytokine production. Key findings from scientific literature using clone 37.51 include:

• T Cell Activation and Costimulation: Clone 37.51 has been used to enhance T cell proliferation and cytokine production, particularly in synergy with T cell receptor (TCR) engagement.
• Flow Cytometry and Immunohistochemistry: The antibody is frequently used in flow cytometric analysis and immunohistochemical staining to study the expression of CD28 on mouse T cells and other immune cells.
• In Vitro and In Vivo Applications: Clone 37.51 is utilized both in vitro and in vivo for costimulation of T cells, promoting CTL development and augmenting IL-2 and IL-2 receptor expression.
• NK Cell Studies: Although primarily focused on T cells, CD28 expression on NK cells has also been studied using this clone, highlighting its broad utility in immunological research.

Overall, clone 37.51 is a versatile tool in immunology research, facilitating the study of T cell biology and immune responses.

Dosing regimens of clone 37.51 (anti-mouse CD28 antibody) vary significantly across mouse models, primarily depending on dose, frequency, route of administration, and purpose. Different studies and vendors report variations, with doses ranging from less than 0.5 μg per sample for flow cytometry to 10–30 μg per injection in in vivo therapeutic experiments.

Essential Context and Supporting Details

• Mouse Strain Differences: Common strains include C57BL/6 and BALB/c; specific immune background and tumor models may necessitate distinct regimens.

• Dosage Range:

  • For in vivo functional experiments, dosing commonly falls between 10 to 30 μg per injection, with most regimens using intraperitoneal or intravenous routes.
  • In toxicity and efficacy studies, 10 μg per injection is reported as effective with minimal toxicity, while higher doses (30 μg per injection) increase risks such as neutropenia and rare treatment-related deaths.
  • For in vitro stimulation or flow cytometry, doses may be much lower, typically ≤0.5 μg per sample.

• Frequency and Duration:

  • Experiments often use biweekly (twice per week) dosing for therapeutic trials in tumor-bearing models, with repeat injections for multiple cycles.
  • Specific protocols may vary from a single dose to four or more repeated treatments, depending on study design and targeted outcome.

• Route of Administration:

  • Intratumoral and intraperitoneal (i.p.) injections are most common; intravenous (i.v.) routes are also used depending on model and scientific objective.

• Purpose of Use:

  • In tumor immunotherapy models, clone 37.51 is used to modulate T cell responses. Regimens are tailored to balance efficacy and minimize toxicity, especially when combined with other antibodies or therapies.
  • In GVHD (graft-versus-host disease) prevention models, clone 37.51 is administered to inhibit T cell expansion, with regimens adjusted accordingly.

Additional Relevant Information

• No universal dosing standard—regimens are customized per experimental goal, mouse strain, and tissue context.
• Vendors provide guidelines and technical details but recommend consulting primary literature and pilot experiments to optimize dosing.

In summary:

• Typical in vivo dosing: 10–30 μg per injection, with lower doses preferred to minimize toxicity.
• Frequency: Biweekly or per protocol, up to four injections.
• Route: Intraperitoneal, intravenous, or intratumoral, depending on the model.
• Regimen variation is substantial across mouse strains and disease models, requiring protocol optimization by individual investigators.