Recombinant Human ICOS

Inducible co-stimulator (ICOS), also called ALIM and H4, is a homodimeric protein and member of the CD28 family of immune co-stimulatory receptors. Other family members are CD28, CTLA-4 and PD-1. ICOS enhances all basic T cell responses to a foreign antigen, namely proliferation, secretion of lymphokines, up-regulation of molecules that mediate cell-cell interaction, and effective help for antibody secretion by B cells. Unlike the constitutively expressed CD28, ICOS has to be de novo induced on the T cell surface, does not up-regulate the production of IL-2, but superinduces the synthesis of IL-10, a B cell-differentiation factor (1). In vivo, ICOS is highly expressed on tonsillar T cells, which are closely associated with B cells in the apical light zone of germinal centres, the site of terminal B cell maturation. ICOS regulates CD28-dependent and CD28-independent CD4 (+) subset (Th1 and Th2) responses (2). It is a major regulator of the adaptive immune system and therefore, has a protective role in inflammatory autoimmune diseases (3).

The biological activity of Human ICOS was determined by the ability to inhibit human T cell proliferation induced by rhB7H2 in the presence of anti-CD3. ¹ The expected ED₅₀ is 1 - 4 μg/ml in the presence of 3 μg/ml rhB7H2 and anti-CD3 immobilized at 20 ng/ml.

Fc Fusion Protein

eingsanyem fifhnggvqi lckypdivqq fkmqllkggq ilcdltktkg sgntvsiksl kfchsqlsnn svsfflynld hshanyyfcn lsifdpppfk vtltggylhi yesqlccqlk fiegrmdpks cdkthtcppc papellggps vflfppkpkd tlmisrtpev tcvvvdvshe dpevkfnwyv dgvevhnakt kpreeqynst yrvvsvltvl hqdwlngkey kckvsnkalp apiektiska kgqprepqvy tlppsrdelt knqvsltclv kgfypsdiav ewesngqpen nykttppvld sdgsfflysk ltvdksrwqq gnvfscsvmh ealhnhytqk slslspgk

Glu21

Lyophilized

The predicted molecular weight of Recombinant Human ICOS is Mr 40.3 kDa. However, the actual molecular weight as observed by migration on SDS-PAGE is Mr 50-60 kDa.

40.3

This recombinant protein was 0.2 µm filtered and lyophilized from modified Dulbecco’s phosphate buffered saline (1X PBS) pH 7.2 – 7.3 with no calcium, magnesium, or preservatives.

This lyophilized protein is stable for six to twelve months when stored desiccated at -20°C to -70°C. After aseptic reconstitution, this protein may be stored at 2°C to 8°C for one month or at -20°C to -70°C in a manual defrost freezer. Avoid Repeated Freeze Thaw Cycles. See Product Insert for exact lot specific storage instructions.

Next Day Ambient

1. Wang, S. et al. (2000) Blood 96:2808
2. Flavell, RA. et al. (2001) Nature 409:97
3. Bachmann, MF. et al. (2000) J. Exp. Med. 192:53
4. Kroczek, RA. et al. (1999) Nature 397:263