Anti-Human CD45 (Clone T29/33) – Purified in vivo GOLD^TM Functional Grade

Clone T29/33 is primarily used in vivo in mice to target and deplete or characterize human hematopoietic cells in xenograft and humanized mice models. This monoclonal antibody is specific to human CD45, a pan-leukocyte marker expressed on all human nucleated hematopoietic cells, but does not bind murine CD45, making it ideal for distinguishing and manipulating human cells in a murine environment.

Common in vivo applications include:

• Tracking, characterization, and quantification of human hematopoietic cells after engraftment in mice (e.g., humanized mice), using flow cytometry or immunohistochemistry.
• Depletion of human leukocytes (by antibody-mediated targeting) to study effects on immune or disease processes, or to manipulate graft composition in transplantation or cancer studies.
• Functional assays of human immune cell populations, such as monitoring reconstitution, activation, or migration in preclinical models of human immunity, transplantation, hematological malignancies, or gene editing.

Additional details:

• T29/33 is used in vivo because of its specificity, high purity, and low endotoxin content, ensuring safety and efficacy for live animal studies.
• It is particularly useful in experiments requiring distinction between human and mouse leukocytes, as in chimeric models for immunology, oncology, or stem cell research.
• Non-cytotoxic in the presence of complement, allowing for non-destructive identification or tracking of human cells.

Summary Table: Common in vivo applications of clone T29/33 in mice

T29/33 is not reactive to mouse CD45 and is used exclusively for human-specific applications in mice, most commonly in immunology, hematology, transplantation, and preclinical testing of human cell therapies. No evidence is found of its use beyond these contexts.

Commonly Used Antibodies and Proteins Paired with T29/33 in the Literature

T29/33 is a widely used monoclonal antibody clone targeting the human CD45 antigen, also known as Leukocyte Common Antigen (LCA), which is expressed on all nucleated hematopoietic cells. Beyond its standalone diagnostic and research uses, T29/33 is frequently paired with other antibodies and proteins in flow cytometry and immunohistochemistry to provide more detailed cell characterization.

Common Pairings with T29/33

Key Applications and Examples

• Flow Cytometry Panels: T29/33 is often included in multi-parameter flow cytometry panels to gate on total leukocytes/granulocytes. For example, it is paired with anti-CD14 (clone TÜK4) in dual-color assays to distinguish different hematopoietic subsets (e.g., monocytes vs. lymphocytes).
• Diagnostic Pathology: In immunohistochemistry, T29/33 is used to confirm the hematopoietic origin of undifferentiated tumors. Negative staining with T29/33, in conjunction with positive staining for markers like cytokeratins (epithelial) or vimentin (mesenchymal), helps rule out lymphoma and support a diagnosis of carcinoma or sarcoma.
• Positive Control: T29/33 is sometimes used as a positive control when validating other anti-CD45 clones or new antibody panels in both flow cytometry and tissue staining.
• Progenitor/Stem Cell Studies: Since CD45 is expressed on all hematopoietic progenitors, T29/33 is used in studies of bone marrow and hematopoietic stem cells, often alongside markers for specific lineages (e.g., CD34 for progenitors, CD3 for T-cells, CD19 for B-cells).

Notes

• Isoforms: CD45 exists as multiple isoforms due to alternative splicing. While T29/33 recognizes a common epitope on all isoforms, some studies may pair it with antibodies specific to particular CD45 isoforms (e.g., CD45RA, CD45RO) for more refined subset analysis.
• Species Specificity: T29/33 is specific for human CD45 and does not cross-react with non-hematopoietic cells in human tissue.
• Complement Lysis: Unlike some other CD45 antibodies, T29/33 is not cytotoxic in the presence of complement, making it suitable for functional assays.

Conclusion

The most commonly paired antibody with T29/33 in the literature is CD14 (clone TÜK4), especially in flow cytometry for leukocyte subset analysis. In pathology, T29/33 is used alongside epithelial and mesenchymal markers to differentiate hematopoietic from non-hematopoietic malignancies. It is also used as a positive control with other CD45 antibodies in experimental validation studies. For more specialized applications, such as progenitor research, T29/33 may be combined with lineage-specific markers (e.g., CD34, CD3, CD19).

Clone T29/33 is a monoclonal antibody targeting human CD45, a pan-hematopoietic antigen widely used in scientific studies to identify and characterize hematopoietic cells and related neoplasms.

Key findings from the literature:

• Diagnostic Utility in Oncology: Clone T29/33 recognizes a 200 kDa glycoprotein (CD45) expressed on nearly all hematopoietic cells. It reliably stains the majority of hematopoietic tumors, making it a useful tool for distinguishing lymphomas from non-hematopoietic neoplasms that do not express CD45, such as carcinomas or most sarcomas. In one large study, T29/33 staining was positive in almost all hematopoietic tumors except for some plasmacytomas, and was negative in most non-hematopoietic undifferentiated tumors.

• Specificity and Isoforms: The T29/33 antibody is used as a positive control for CD45 expression, confirming the presence across all known isoforms of the molecule generated via alternative splicing (ABC, AB, BC, B, and O). This makes it valuable in flow cytometry and immunohistochemistry to broadly identify hematopoietic cells regardless of their developmental stage.

• Cell Signaling Insights: CD45, recognized by clone T29/33, is a key regulator of immune cell activation and differentiation. It acts through its extracellular and cytoplasmic domains, negatively regulating cytokine receptor signaling (notably via suppression of JAK kinase).

• Clinical Laboratory Use: Clone T29/33 is routinely employed in assays for identifying circulating tumor cells (CTCs), where anti-CD45 staining is used to exclude hematopoietic cells from detection panels focused on epithelial (cancer) cells.

• Rare Cross-Reactivity: While highly specific for hematopoietic cells, rare exceptions have been described (e.g., one sarcoma positive for CD45), underscoring its utility but also the need for corroborative diagnostic studies.

• Blocking/Inhibition Phenomena: Some patient plasma samples can specifically inhibit anti-CD45 (including T29/33) staining, suggesting potential interference factors in certain clinical contexts.

In summary, clone T29/33 is a cornerstone reagent for immunophenotyping hematopoietic cells, supporting tumor classification, cell sorting, and functional studies of immune cell regulation. Its broad specificity for CD45 isoforms and robust performance in pathology underscores its value and frequent citation in scientific literature.

There are currently no published, standardized dosing regimens for clone T29/33 (an anti-human CD45 antibody) in mouse models according to available search results. Most dosing guidelines for in vivo antibody use in mice focus on other frequently used clones (such as anti-CD4, anti-CD8, and anti-PD-1 clones), but clone T29/33 is not explicitly discussed in these resources.

Key context:

• Leinco notes that there are no published, standardized dosing regimens for T29/33 in mouse models. They reference its use as a functional-grade reagent for in vivo work but do not provide detailed schedules or dosages.
• General in vivo antibody dosing for similar functional antibodies in mice (for other targets) ranges widely, typically 100–250 µg per mouse delivered intraperitoneally, with dosing schedules of every 2–4 days depending on the target and application. However, these values should only be used as ballpark references and not assumed to apply directly to T29/33.

Additional relevant information:

• If T29/33 is used to deplete, block, or label human leukocyte antigens in humanized mouse models or xenografts, dosing should be empirically determined for each unique setting, ideally guided by pilot studies or manufacturer technical support, since reactivity, kinetics, and toxicity may differ from standard murine or anti-mouse reagents.
• As T29/33 targets human CD45, it is typically used in humanized mouse experiments or for tracking human hematopoietic engraftment, rather than conventional mouse models.

Summary:
Dosing regimens for clone T29/33 across different mouse models are not standardized or well-documented in the literature or antibody manufacturer data. Regimens for similar antibodies often range from 100–250 µg per mouse every 2–4 days, but such estimates must be validated in context. Consultation with technical support or pilot study data is recommended when planning experiments using T29/33.