CD81 (TAPA-1, Target of anti-Proliferative Antibody-1)

CD81, also known as TAPA-1 or Target of the antiproliferative antibody, is a 236 amino acid ~26kD multipass transmembrane protein belonging to the TM4SF family (UniProt: P35762). In rodents CD81 is expressed at much higher levels on resting B cells than on T cells, although increased expression on T cells is found following activation. C2433-12A induces homotypic aggregation of B cells and inhibits anti Ig and IL-4 induced proliferation (Maecker et al. 2000). C2433-12A requires the presence of both extracellular loops of TAPA-1 for binding. Mice lacking CD81 demonstrate reduced fertility through impaired oocyte-sperm fusion, double knockout CD81-/- CD9-/- mice are completely infertile suggesting complimentary roles in oocyte-sperm fusion (Rubenstein et al. 2006).

Applications:
Suitable for use in Flow Cytometry, ELISA, Western Blot, Immunoprecipitation and Immunohistochemistry. Other applications not tested.

Recommended Dilution:
Flow Cytometry: 1:10-1:50. Use 10ul to label 10e6 cells in 100ul.
Immunohistochemistry (frozen): The recognized epitope is reported to be sensitive to formaldehyde fixation and tissue processing. Use of acetone fixation is recommened.
Western Blot: non-reducing conditions
Optimal dilutions to be determined by the researcher.

Hybridoma:
Spleen cells from immunized Armenian hamsters were fused with cells of the mouse PX3-Ag.8.653 myeloma cell line.

Recommended Secondary Reagents:
I1903-04T: IgG H&L (HRP) Pab Gt x Hm
I1903-04Q: IgG H&L (FITC) Pab Gt x Hm

Recommended Negative Controls:
Hamster IgG Negative Control

Storage and Stability:
May be stored at 4°C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Aliquots are stable for 12 months after receipt. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.