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B6-CD45.1 mice

Jiangsu Aniphe BioLab boasts a standardized laboratory animal platform and offers a steady, long-term supply of B6‑CD45.1 mice in stock. As a cornerstone tool for immunology, hematopoietic stem cell transplantation, and cell‑tracking studies, we provide high‑quality mouse colonies with well‑defined genetic backgrounds, high homozygosity, and excellent strain health. With ample inventory and a rapid response system, we help you effortlessly establish adoptive transfer and chimeric models, ensuring the rigor and efficiency of your research data.

Strain Introduction

B6-CD45.1 mice are a strain generated on the C57BL/6 genetic background by introgression of the Ptprcᵃ (CD45.1/Ly5.1) allele. Wild-type C57BL/6 mice express CD45.2 (Ly5.2), whereas this strain expresses only CD45.1. Because antibodies against CD45.1 and CD45.2 exhibit clear, non‑cross‑reactive specificity and can be used for flow cytometric differentiation, B6‑CD45.1 mice have become the gold standard tool for tracking hematopoietic and immune cells, as well as for studies involving bone marrow transplantation, adoptive transfer, and chimerism.

The strain exhibits normal immune function, with no reported effects on hematopoiesis or immune development, and all hematopoietic cells—including T and B cells, myeloid cells, and erythrocytes—stably express CD45.1, enabling precise in vivo and in vitro discrimination of donor- versus recipient‑derived cells.

Product Advantages

The background is clean, and experimental interference is minimal.

Based on a standardized C57BL/6‑derived congenic strain, the CD45.1 allele has been stably fixed through successive backcrossing, resulting in an immune and hematopoietic system that closely resembles that of conventional B6 mice. This approach effectively minimizes the confounding effects of strain‑specific background differences in studies of inflammatory responses, hematopoietic reconstitution, and antigen presentation.

Exclusive labeling, precise cell tracking

Leveraging the antigenic specificity differences between CD45.1 and CD45.2, with no antibody cross-reactivity, this approach enables robust discrimination of donor and recipient cells by flow cytometry, making it the gold standard for hematopoietic and immune cell tracing studies.

Strong immunity, suitable for a wide range of applications.

Mice do not exhibit congenital immune deficiencies; following bone marrow transplantation, they demonstrate highly efficient hematopoietic reconstitution and normal in vivo immune cell responses, making them well suited for studies requiring a fully intact immune microenvironment, such as tumor immunology, autoimmune diseases, and infectious disease immunity.

High resolution, supporting multidimensional research.

Chimeric bone marrow models of multiple lineages can be generated using CD45.1/CD45.2 heterozygotes, enabling precise differentiation of cells from distinct origins and facilitating detailed mechanistic studies on hematopoietic stem cell function, immune development, and cellular interactions within the tumor microenvironment.

Data parameters

Strain Name

B6-CD45.1 mouse
Targeted gene

Ptprc
Mutant site

Ptprcᵃ (CD45.1/Ly5.1 allele, SJL/J origin)
Types of gene editing

Congenic strains are established through repeated backcrossing to C57BL/6.
Genetic background

C57BL/6J
Microbial Grade

SPF grade

Validate data

Selection of CD45.1 Mouse Models: Genetic Background Differences That Should Not Be Overlooked

The classic B6.SJL-CD45.1 congenic mouse strain, generated through multiple generations of backcrossing, cannot completely eliminate the SJL parental genomic segments flanking the CD45 locus. The extent of these exogenous fragments varies significantly among breeding colonies of different strains; they harbor numerous immune‑regulatory genes that can readily confound in vivo experimental outcomes—such as T‑cell function and hematopoietic reconstitution—and thus constitute a major source of poor experimental reproducibility. In mechanistic studies and high‑level research projects, the site‑specific knock-in CD45.1 mouse, which carries a single‑site modification of the Ptprc gene without large intervening sequences, is better suited for immunological tracing experiments that demand exceptionally high background purity.

 

 

When selecting B6-CD45.1 mice, the supplier’s background is an important confounding factor.

The commercial B6.SJL-CD45.1 mouse strain exhibits variable genomic segments derived from SJL mice, depending on the breeding supplier, which in turn leads to pronounced differences in the Th1 cell transcriptome. These differential hotspots are concentrated within a key interval we previously identified on chromosome 1 and also implicate multiple loci on chromosomes 19 and 7. These findings suggest that, when using B6.SJL-CD45.1 mice in experiments, the supplier background constitutes a critical confounding factor that can influence T‑cell–related gene expression phenotypes and is of paramount importance for experimental reproducibility.

 

Application areas

● Hematopoietic Stem Cell Transplantation and Bone Marrow Chimerism Models
● Adoptive transfer of immune cells and in vivo tracking
● Study of Immune Development in Mixed Bone Marrow Chimeras
● Tumor immunology (distinguishing between host and transplanted immune cells within a xenograft)
● Cell‑of‑origin tracing in autoimmune and inflammatory models
● Cell Identity Identification in Chimeric Conditional Gene-Editing Systems

Breeding Techniques and Precautions

Strictly control inbreeding systems to mitigate genetic divergence.

Genetic identification

CD45.1 and CD45.2 expression can be accurately distinguished by flow cytometry; it is recommended to collect 20–50 µL of tail tip blood or peripheral blood for staining. Alternatively, PCR-based genotyping targeting Ptprcᵃ may be used as an auxiliary method.

 

Strictly control environmental stimuli to reduce experimental stress.

Maintain herd expansion

It is recommended to maintain homozygous (CD45.1⁺/CD45.1⁺) breeding; all offspring will express CD45.1, eliminating the need for continuous screening. Avoid co-housing with CD45.2 strains to prevent genetic contamination.

 

Standardize breeding management to improve the survival rate of pups.

Reproductive performance

It exhibits reproductive performance comparable to that of standard C57BL/6 mice, with normal fertility when males and females are mated, and requires no special dietary supplementation.

Monitor age-related spontaneous lesions and eliminate experimental confounding.

Transport and Adaptation

Environmental changes do not transiently affect CD45 antigen expression; however, prior to the formal experiment, it is recommended to acclimate the animals for 5–7 days and include sex- and age-matched control groups.

Literature support

References: Defining genetic variation in widely used congenic and backcrossed mouse models reveals varied regulation of genes important for immune responses.
Research papers published by Aniphe customers using this model are eligible for SCI-indexed publication. (Original paper link)
BMC Med. 2023 Aug 21;21(1):315.
Abnormal generation of IL-17A represses tumor infiltration of stem-like exhausted CD8+ T cells to demote the antitumor immunity.

Frequently Asked Questions

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Q1: Apart from antigenicity, do CD45.1 and CD45.2 affect immune function?

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A: The two are allelic variants of Ptprc, with no functional differences; they exhibit equivalent immune response and hematopoietic reconstitution capacities and are used solely as genetic markers.

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Q2: Is it possible to co-house CD45.1 and CD45.2 mice long-term for sensitization?

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A: The risk of non‑homologous immune recognition is extremely low; however, it is recommended to maintain strict separate housing to prevent unintended mating that could lead to genotypic confusion. If short‑term co‑housing for experimental purposes is unavoidable, clear and unambiguous labeling must be implemented.

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Q3: Is CD45.1 expression influenced by age and inflammatory status?

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A: CD45.1 is stably expressed on hematopoietic cells and is unaffected by normal aging or standard inflammatory models; however, its expression level may be slightly downregulated in certain highly activated granulocytes, yet it remains detectable for cell discrimination.

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Q4: How can we verify whether recipient-derived cells have been completely eliminated after transplantation?

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A: Chimerism analysis is performed using dual staining with CD45.1 and CD45.2; if recipient-derived CD45.2 cells are still detected, the clearance regimen should be reassessed. Combining this approach with lineage-specific markers allows for further characterization of the origins of individual subpopulations.

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Q5: Is the CD45 isoform analysis affected after crossing with NSG and other immunodeficient mice?

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A: CD45.1/2 staining is not affected by the absence of immune cells; however, it should be noted that an immunodeficient background may result in low peripheral white blood cell counts. For reliable phenotyping, we recommend using bone marrow or splenic cells.

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