ACROBiosystems 特集商品紹介ページ


A team from Peking University published their work about the screening of the neutralizing antibodies against SARS-CoV-2 in top journal Cell early this year. In their work, they used RBD and S protein pre-coupled magnetic beads to enrich the RBD binding B cells. Compared to the traditional cell isolation method, the pre-coupling beads help to increase the efficiency to 20-fold.[1]

Fig. 1 Workflow of the pre-coupling magnetic beads

The biotinylated proteins were conjugated to streptavidin magnetic beads. Magnetic particles from alternative suppliers often have random sizes and surface area which could compromise your assay performance. ACRO screened a few different beads and bring this tightly controlled superparamagnetic microspheres to you. The beads are in uniform size, narrow size distribution with large surface area and unique surface coating, which can help you get the best performance and highly reproducible results.

Our pre-coupled beads could capture the molecules which have affinity to the pre-coupled proteins from various assay systems, and make the following testing easy.

>>> Applications: Immunocapture, Biopanning, Sample/cell enrichment, Sample pre-treatment for analytical assays, Flow cytometry analysis.

Product List

Molecule Cat. No. Product Description Species
S1 protein MBS-K001 SARS-CoV-2 Spike S1 protein-coupled magnetic beads SARS-CoV-2
S protein RBD MBS-K002 SARS-CoV-2 Spike protein RBD-coupled magnetic beads SARS-CoV-2
CD3 MBS-K003 CD3 epsilon&CD3 delta Heterodimer protein-coupled magnetic beads Human
BCMA MBS-K004 BCMA-coupled magnetic beads Human
CD19 MBS-K005 CD19-coupled magnetic beads Human
HER2 MBS-K006 HER2-coupled magnetic beads Human
ACE2 MBS-K013 Human ACE2-coupled magnetic beads SARS-CoV-2
S protein RBD MBS-K014 Anti-SARS-CoV-2 Spike RBD Antibody-coupled magnetic beads SARS-CoV-2
PSMA MBP-K007 PSMA-coupled magnetic beads Human
CD33 MBC-K008 CD33-coupled magnetic beads Human
ROR1 MBR-K009 ROR1-coupled magnetic beads Human
CD38 MBC-K010 CD38-coupled magnetic beads Human
EpCAM MBE-K011 EpCAM-coupled magnetic beads Human
EGFR MBE-K012 EGFR-coupled magnetic beads Human

>>> Relevant recommendation:
Cat.No. MB-12 Magnetic beads blocking buffer (We recommend using our blocking buffer together with the pre-coupling beads for immunocapture.)
Cat.No. SMB-B01 Magnetic beads™ Streptavidin (We recommend using our non-coupling streptavidin magnetic beads as a control)

Features and Advantages

Low non-specific binding

ACRO chose the uniform, better-shaped paramagnetic beads to reduce the non-specific binding.

Fig. 2 TEM data of different magnetic beads. A is ACRO’s magnetic beads; B and C are competitors’ beads.

High efficiency

Our pre-coupling beads are at the level of saturation. A maximum amount of proteins can ensure the best capture performance, which could increase the efficiency of your assay.

According to the static adsorption experiment result, the RBD pre-coupling magnetic beads can be used to capture the anti-SARS-CoV-2 S1 antibody. RBD pre-coupling amount is greater than 40ug/mg beads.

Fig 3. The binding curve between RBD pre-coupling magnetic beads and anti-SARS-CoV-2 antibody.

Fig. 4 The binding curve between RBD pre-coupling magnetic beads and ACE2 protein. 0.1 mg of Beads (1mg/mL, 100 L) was washed three times and the supernatant was removed. Antibodies of the corresponding concentration of 100 L (10 g/mL~0.039 g/mL) were added. One hour later,fluorescent labeled secondary antibody was added for another one-hour-reaction, the corresponding Binding signal was detected and the Binding curve as obtained.

Fig. 5 Use BCMA pre-coupled magnetic beads to capture the anti-BCMA antibody. Anti-BCMA antibody can all be captured before the maximum binding capacity is reached. The PE-labeled secondary antibody is used for detection.


Our pre-coupling beads are lyophilized for long term storage. It is ready to use after reconstitution. No need for activation which could greatly save your time and hassle.

[1] Cao, Y., et al., Potent neutralizing antibodies against SARS-CoV-2 identified by high-through put single-cell sequencing of convalescent patients’ B cells, Cell (2020), doi:



Enzyme-linked immunosorbent assays (ELISA) have been around as one of the primary methods of analyte detection for decades. It is regarded as the most accessible and flexible assay formats for the biological assays. ELISA can be used for biopanning, molecule screening, molecule quantification, pharmacokinetic assays and immunogenicity assays, etc. ACRO took the advantages of our own comprehensive list of target protein products, and developed a serial of ready-to-use universal ELISA kits. These ELISA kits will greatly save your time and hassle for your drug development process.

What is included in our kit

・One 96-well streptavidin plate

・Antigen protein – Avi tag

・HRP- secondary antibody

・Diluent Buffer: for blocking and sample dilution

How the ELISA kits work

Fig.1 The assay principle of the ELISA kit

Product List

Cat. No. Product Size
TAT-K004 Anti-TIGIT ELISA kit 96 tests
TAH-K005 Anti-Her-2 ELISA kit 96 tests
TAL-K006 Anti-LAG-3 ELISA kit 96 tests


Low background noise

The serum samples contain many factors that may potentially interfere with the indirect ELISA result. This is the major reason for the background issue. We include the diluent buffer in the kit to help solving the problem.

Fig. 2 Determination of serum drug concentration using anti-Her-2 ELISA Kit

High sensitivity and wide detection range

Our ELISA kits utilized an indirect ELISA format. Antigen coating is achieved through the binding between biotin and streptavidin. The sensitivity can reach the level of ng/ml. The detection range is about 2 to 3 logs

Fig.3 Immobilized human LAG-3 protein, Avi Tag (Cat. No. LA3-H82E5) at 1 μg/mL (100 μL/well) can bind Anti-LAG-3 Neutralizing Antibody with a linear range of 4.096-160 ng/mL

Consistent performance

We install rigorous quality control program to ensure the lot-to-lot consistency. Every batch of products are analyzed to meet our internal standards. The product will be released only if all standards are met.

Fig.4 Determination of serum drug concentration using anti-TIGIT ELISA Kit. Consistent results were achieved when perform the assay on various days



Siglec-15 is a member of the sialic acid-binding Ig-like lectin (Siglecs) family and is expressed in M2 macrophages, myeloid cells, dendritic cells, B cells, and osteoclasts. Siglec-15 can continuously inhibit the activity of T cells and exhibits the main features of normalized cancer immunotherapy. Related studies have shown that Siglec-15 is the major immunosuppressive factor in most PD-L1 negative tumor patients. And the anti-cancer effect of this target is likely to be mutually exclusive with PD-L1. In tumor cells, the expression level of siglec-15 is low when PD-L1 expression is high. For those cancer patients who are not effective in PD-1/PD-L1 treatment, Siglec-15 may bring them a new choice of immunotherapy.

High bioactivity Siglec-15 protein can help drugs development. The bioactivity of Siglec-15 protein developed by ACROBiosystems is verified by Cell based assay/BLI /SPR /ELISA, and the corresponding protocols are provided for free.

Product Features

The bioactivity of Siglec-15 proteins are verified by Cell based assay/ BLI/ SPR/ ELISA, and the protocols are offered.

Cell based assay BLI
Biotinylated Human Siglec-15, Fc,Avitag (Cat. No. SG5-H82F5) inhibits Anti-CD3-induced proliferation of PBMC. The ED50 for this effect is 0.48-0.57 μg/mL. Loaded Anti-Siglec-15 MAb (Mouse IgG) on AMC Biosensor, can bind Human Siglec-15, Fc Tag (Cat. No. SG5-H5253) with an affinity constant of 59.7 pM as determined in BLI assay (ForteBio Octet Red96e).
Immobilized Neu5Ac(a2-6)GalNAc-PAA-biotin on SA Chip can bind Human Siglec-15, Fc Tag (Cat. No. SG5-H5253) with an affinity constant of 4.49 μM as determined in a SPR assay (Biacore T200). Immobilized Mouse Human chimeric MAb (5G12, Human IgG1) at 5 μg/mL (100 μL/well) can bind Biotinylated Human Siglec-15, Fc,Avitag (Cat. No. SG5-H82F5) with a linear range of 0.4-3 ng/mL.

More species and tags to choose.

Molecule Cat. No. Host Product Description Structure
Siglec-15 SG5-H5253 HEK293 Human Siglec-15 / CD33L3 Protein, Fc Tag
SG5-H5254 HEK293 Human Siglec-15 / CD33L3 Protein, Mouse IgG2a Fc Tag
SG5-H52H3 HEK293 Human Siglec-15 / CD33L3 Protein, His Tag
SG5-H82E9 HEK293 Biotinylated Human Siglec-15 / CD33L3 Protein, His,Avitag™ (recommended for biopanning)
SG5-H82F5 HEK293 Biotinylated Human Siglec-15 / CD33L3 Protein, Fc,Avitag™
SG5-M52H7 HEK293 Mouse Siglec-15 / CD33L3 Protein, His Tag
SG5-C5253 HEK293 Cynomolgus Siglec-15 / CD33L3 Protein, Fc Tag
SG5-C52H6 HEK293 Cynomolgus Siglec-15 / CD33L3 Protein, His Tag

* If you want more Siglec proteins, please click the molecule name below to find more.

Siglec Proteins
Siglec-2 Siglec-3 MAG / Siglec-4a
Siglec-5 Siglec-6 Siglec-8
Siglec-9 Siglec-10 Siglec-15