Rat Ig Kappa Light Chain Mouse mAb: Protocol & Usage Guide

Rat Ig Kappa light chain Mouse mAb is a mouse-derived monoclonal antibody specifically targeting the kappa (κ) light chain of rat immunoglobulins, designed for reliable detection and characterization of rat antibodies in a variety of immunological assay formats.

Product SKU

Ab349243

Antibody Type

Mouse Monoclonal Antibody (mAb)

Target Antigen

Rat Immunoglobulin Kappa (κ) Light Chain

Host Species

Mouse

Reactivity

Rat

Reference Catalog

absea#KC-2674

Overview and Principle

Rat Ig Kappa light chain Mouse mAb (Ab349243) is a mouse monoclonal antibody raised against the kappa (κ) light chain of rat immunoglobulins. In mammals, immunoglobulin light chains exist as two isotypes: kappa (κ) and lambda (λ). The kappa light chain is the predominant isotype in most species and is shared across all immunoglobulin classes (IgG, IgM, IgA, IgE, and IgD). By targeting an epitope on the constant region of the rat κ light chain, this antibody can detect all rat immunoglobulin subclasses that carry the kappa light chain in a class-independent manner.

This specificity makes Ab349243 a broadly applicable secondary or detection reagent in experiments using rat-derived primary antibodies, enabling robust identification of rat antibodies in complex biological samples without cross-reactivity to immunoglobulins of other species.

Recommended Protocol

General Preparation:

• Reconstitute lyophilized antibody according to the datasheet instructions. Centrifuge briefly before opening to collect contents at the bottom of the vial.
• Prepare all buffers and blocking solutions in advance. Use phosphate-buffered saline (PBS, pH 7.4) as a standard diluent unless otherwise specified.

ELISA Protocol (Indirect):

1. Coat 96-well microplate with rat IgG or sample antigen at 1–10 µg/mL in coating buffer overnight at 4 °C.
2. Wash plate 3× with PBST (PBS + 0.05% Tween-20).
3. Block with 1–5% BSA or non-fat dry milk in PBS for 1 hour at room temperature.
4. Wash 3× with PBST.
5. Add Ab349243 at the recommended working dilution (refer to product datasheet; typical starting dilution 1:500–1:2000) in blocking buffer. Incubate 1 hour at room temperature or overnight at 4 °C.
6. Wash 3× with PBST.
7. Add appropriate HRP- or AP-conjugated secondary anti-mouse antibody. Incubate 1 hour at room temperature.
8. Wash 3× with PBST, then develop with TMB or pNPP substrate. Stop reaction and read absorbance.

Western Blot Protocol:

1. Separate rat immunoglobulin-containing samples by SDS-PAGE under reducing or non-reducing conditions.
2. Transfer to PVDF or nitrocellulose membrane.
3. Block membrane with 5% non-fat dry milk in TBST for 1 hour at room temperature.
4. Incubate with Ab349243 at recommended dilution overnight at 4 °C.
5. Wash 3× with TBST (10 minutes each).
6. Incubate with HRP-conjugated anti-mouse secondary antibody for 1 hour at room temperature.
7. Wash 3× with TBST. Detect bands by ECL chemiluminescence.

Flow Cytometry Protocol:

1. Harvest cells and wash with cold PBS. Adjust to 1×10⁶ cells per tube.
2. Block non-specific binding with 1–2% BSA in PBS for 15–30 minutes on ice.
3. Add Ab349243 at recommended dilution. Incubate 30–60 minutes on ice in the dark.
4. Wash twice with cold PBS.
5. Add fluorochrome-conjugated anti-mouse secondary antibody. Incubate 20–30 minutes on ice.
6. Wash twice with cold PBS and resuspend in PBS with 1% paraformaldehyde or acquire immediately.

Storage, Handling, and Quality Control

Storage Conditions: Store Ab349243 at −20 °C for long-term preservation. Avoid repeated freeze-thaw cycles, which can degrade antibody performance. Aliquot upon first use to minimize freeze-thaw events. Once reconstituted or diluted, short-term storage at 2–8 °C is acceptable for up to one week. Addition of a carrier protein (e.g., 0.1% BSA) and a preservative such as sodium azide (0.02%) may extend working-solution stability.

Handling Precautions: Keep the antibody on ice during use. Avoid prolonged exposure to light if the antibody is conjugated to a fluorochrome or is being used alongside fluorescent secondary reagents. Centrifuge vials briefly before opening to recover all material.

Quality Control: Each lot of Ab349243 should be lot-release tested for specificity against rat kappa light chain and for absence of cross-reactivity with lambda light chains and non-rat immunoglobulins. Consult the Certificate of Analysis (CoA) for lot-specific purity, concentration, and functional test data supplied by Aladdin Scientific.

Troubleshooting

The following table summarizes common issues encountered when using Rat Ig Kappa light chain Mouse mAb and suggested corrective actions:

• No signal or weak signal: Verify that the target sample contains rat kappa-type immunoglobulins. Check antibody concentration and dilution. Ensure secondary antibody is compatible with mouse IgG primary. Confirm that assay incubation times and temperatures were followed correctly.
• High background: Increase blocking stringency (higher BSA or milk concentration, longer blocking time). Reduce primary antibody concentration. Increase wash steps or wash duration. Ensure PBST/TBST detergent concentration is adequate (0.05–0.1% Tween-20).
• Non-specific bands (Western Blot): Optimize antibody dilution. Switch to non-reducing conditions if kappa light chain epitope is conformation-dependent. Ensure fresh preparation of blocking buffer.
• Cross-reactivity concerns: This antibody is directed against rat kappa light chains; however, cross-reactivity with closely related species should be empirically validated. Review the product datasheet for confirmed species reactivity.
• Inconsistent results between lots: Always titrate new lots against a previous lot using a standard positive control sample. Record optimal dilution for each new lot.

Frequently asked questions

What applications is Rat Ig Kappa light chain Mouse mAb (Ab349243) validated for?

Ab349243 is designed for use in common immunological assays including ELISA, Western blot, and flow cytometry for detecting rat kappa light chain-bearing immunoglobulins. Users should consult the product datasheet for the specific validated applications and recommended dilutions for each assay format.

Will Ab349243 cross-react with mouse or human immunoglobulin kappa light chains?

Ab349243 is raised in mice and is specifically targeted to rat immunoglobulin kappa light chains. Cross-reactivity with mouse or human kappa light chains is not expected due to differences in the constant region sequences; however, empirical validation with your specific samples is always recommended before drawing conclusions. Refer to the datasheet for confirmed species reactivity data.

How should I determine the optimal working dilution of Ab349243 for my experiment?

Optimal dilution should be determined empirically by titration for each specific assay and sample type. As a starting point, a dilution range of 1:500–1:2000 is typically used for ELISA, while Western blot and flow cytometry may require different concentrations. Always run a titration series alongside appropriate positive and negative controls to identify the dilution that gives maximal specific signal with minimal background.

Can this antibody be used to detect rat-derived primary antibodies in co-immunoprecipitation (Co-IP) experiments?

In principle, Ab349243 can serve as a secondary detection tool for rat kappa-chain-bearing antibodies in Co-IP experiments, since it targets a conserved region of the rat kappa light chain present on all kappa-type rat immunoglobulins. However, specific validation for Co-IP conditions (including lysis buffers, protein A/G bead compatibility, and elution conditions) has not been confirmed in the available source material and should be tested by the user.

References

1. Absea Biotechnology product reference: KC-2674, Rat Ig Kappa Light Chain Mouse Monoclonal Antibody. Absea Biotechnology Ltd.
2. Janeway CA Jr, et al. Immunobiology: The Immune System in Health and Disease. 5th ed. Garland Science; 2001. Chapter 3: Structure of the Antibody Molecule and Immunoglobulin Genes.

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.