LCR45 Antibody

What is CD45 and why is it important in immunological research?

CD45 molecules are single chain integral membrane proteins comprising at least five isoforms ranging from 180 to 220 kDa . CD45 is a critical regulator of signaling thresholds in immune cells, including T cells, making it an indispensable antigen for immune function . It is also known as the leucocyte common antigen (LCA), B220, T200, and functions as a protein tyrosine phosphatase (EC 3.1.34) . Its importance stems from its essential role in leukemia tumorigenesis and maintenance by regulating response to growth-promoting cytokines, suggesting that CD45 might be an "Achilles' heel" molecule on leukemic cells .

What are the major isoforms of CD45 used in research applications?

Research frequently focuses on specific CD45 isoforms, particularly CD45RC. According to the provided research, CD45RC is expressed by all B cells and plasmacytoid DCs (pDCs), as well as by 40%–75% of CD4+ T cells . Different clones of antibodies recognize distinct epitopes of the CD45RC molecule, including the OX22, OX32, and 3H1437 clones . The J33 clone is another important antibody assigned to the CD45 cluster that recognizes broader CD45 expression .

How do researchers detect and quantify CD45 expression?

CD45 expression is typically detected using fluorochrome-conjugated antibodies specific to CD45 or its isoforms. For example, the CD45-ECD conjugated antibody (clone J33) is designed for flow cytometry applications to identify and quantify CD45 expression on human cells . Flow cytometry analysis allows researchers to distinguish CD45RC high versus CD45RC low/- expression patterns, which can be crucial for identifying different T cell subpopulations .

How are CD45 antibodies being used in CAR-T cell therapy development?

CD45 is being explored as a universal blood cancer antigen that can be targeted with CAR T cells. Researchers have created CAR45 constructs by cloning anti-CD45 single-chain variable fragments (scFvs) from different antibody clones into second-generation CAR lentiviral vectors . The challenge with targeting CD45 with CAR T cells lies in CD45's expression on hematopoietic stem cells (HSCs) and T cells themselves, which can lead to fratricide during manufacturing and severe pancytopenia in patients .

What innovative approaches are being developed to overcome limitations of CD45-targeted therapies?

Instead of completely deleting CD45, researchers are using CRISPR base editing to install nonsynonymous mutations at relevant CD45 epitopes. This "epitope editing" approach enables the target cells to maintain CD45 expression and intracellular phosphatase function while preventing recognition by anti-CD45 CAR T cells . Base editing has advantages over other gene editing methods as it results in lower indel formation, has fewer off-target editing events, and yields higher purity without causing double-strand breaks .

How do CD45RC-targeting antibodies influence transplant tolerance?

Transient antibody targeting of CD45RC has been shown to induce donor-specific transplant tolerance in fully mismatched cardiac allograft models in rats. Administration of mouse IgG1 anti-rat CD45RC mAb (clone OX22) for 10 or 20 days led to indefinite allograft survival in 83.3% and 62.2% of recipients, respectively . This treatment results in a specific total inhibition of anti-donor humoral responses without compromising new or memory humoral immunity against cognate antigens .

What controls should be included when using CD45 antibodies in transplantation models?

When studying transplant tolerance using CD45RC antibodies, proper controls should include untreated recipients and recipients administered with control isotype mAb for the same duration . To assess the impact on general immunity, researchers should challenge treated subjects with unrelated antigens such as Keyhole limpet hemocyanin (KLH) or horse red blood cells (HRBC) and measure the resulting antibody responses .

How can researchers monitor the effects of anti-CD45RC mAb treatment on immune cell populations?

Monitoring should include analyzing the kinetics of different cell populations in peripheral blood before, during, and after treatment. Key measurements include quantifying CD45RC high versus CD45RC low/- expression on CD4+ and CD8+ T cells, as well as tracking the absolute numbers of B cells, NKT cells, NK cells, DCs, and monocytes . Significant timepoints for analysis include day 4 (early effects), day 10 (during treatment), and day 15 (post-treatment) to capture the full dynamic range of cellular changes .

What are the optimal parameters for flow cytometry when analyzing CD45 isoform expression?

For accurate flow cytometric analysis of CD45 isoform expression, researchers should:

• Use appropriate fluorochrome conjugates (e.g., ECD for the J33 clone)

• Include isotype controls (e.g., IgG1 for the J33 clone)

• Employ multi-parameter analysis to simultaneously assess CD45 expression alongside other markers to identify specific cell subsets

• Establish clear gating strategies to distinguish CD45RC high versus CD45RC low/- populations

• Include controls to assess potential antibody-mediated depletion versus masking of the epitope

What is the Atlas LCR45 and how does it differ from CD45 antibodies?

The Atlas LCR45 is an electronic device - specifically an enhanced handheld instrument capable of performing detailed analysis of passive components such as inductors, capacitors, and resistors . It has no relation to CD45 antibodies used in biological research. The LCR in LCR45 stands for Inductance (L), Capacitance (C), and Resistance (R), which are the electrical properties this device measures .

What are the basic capabilities of the LCR45 for research applications?

The LCR45 provides detailed measurement data including component type identification, component value in real engineering units, secondary component values (such as DC resistance of inductors), test frequency used, complex impedance measurements (real and imaginary portions), complex admittance measurements, and magnitude and phase of impedance measurements .

What modes of operation does the LCR45 support for experimental flexibility?

The LCR45 can be used in fully automatic mode or in various manual modes, offering a combination of speed and flexibility. Both component type and test frequency can be set to automatic or manual modes . It also features continuous fluid measurements with a hold function, comprehensive probe compensation measurement, enhanced measurement resolution, and enhanced compensation for component parasitics such as core losses and dielectric losses .

What is probe compensation and why is it critical for accurate impedance measurements?

Probe compensation is an essential calibration procedure for the LCR45 that ensures measurement accuracy by accounting for the inherent impedance of the test probes themselves . This process is particularly important for accurate measurements of low-value components where the probe impedance could significantly affect the readings. The LCR45 includes comprehensive probe compensation measurement capabilities to address this potential source of error .

How do impedance and admittance displays enhance component characterization?

The LCR45 provides both impedance and admittance displays, offering complementary information about component behavior . Impedance (Z) represents the opposition to current flow and is expressed as a complex number with real and imaginary parts, while admittance (Y) is the reciprocal of impedance and represents how easily current flows through a component . These dual perspectives allow researchers to better understand component behavior, particularly for complex components with multiple parasitics.

What are the key technical specifications researchers should consider when planning experiments with the LCR45?

Researchers should consider the measurement ranges of the LCR45 when planning experiments. The device has specific capacitance and inductance measurement ranges as detailed in the user guide . Understanding these ranges is essential for experimental design to ensure that components being tested fall within the measurable limits of the device.

How should researchers interpret component display results for accurate characterization?

The component display provides information about the type of component detected (resistor, inductor, or capacitor) along with its primary value and, where applicable, secondary parameters . Researchers should understand how to interpret these results in the context of their specific application, recognizing that component behavior can vary with frequency and that parasitics can significantly influence measurements.

What troubleshooting approaches should be employed when unexpected results occur?

When unexpected results occur, researchers should consider potential sources of error including:

• Ensure proper probe compensation has been performed

• Verify that the component is properly connected and not influenced by external fields

• Check that the component is within the measurable range of the device

• Consider whether the test frequency is appropriate for the component being measured

• Consult the troubleshooting section of the user guide which provides guidance for specific issues