Antibodies - K1

The K1 IgG2a monoclonal antibody recognises dsRNA with similar affinity to our widely used J2 antibody and is also sold in lyophilised form. It can be used for the histological and cytological detection of dsRNA in cells and tissues.

It has proven especially useful as an alternative to J2 to resolve cross-reactions and/or remove unwanted background, in those rare experimental setups where J2 did not provide satisfactory results.

K1 can be used to detect dsRNA intermediates of viruses as diverse as Hepatitis virus, Theiler’s murine encephalomyelitis virus or Japanese encephalitis virus. It has been for the detection of dsRNA in cultured cells and in fixed paraffin-embedded histological samples (see publications).

If Poly I:C needs to be detected we highly recommend using K1 rather than J2 because K1 has a much higher affinity for this synthetic polyribonucleotide (see Schönborn et al. 1991, Fig. 2).

K1 has been used successfully in immunofluorescence microscopy, in flow cytometry (FACS) and in immunocapture methods (such as dot-blot and ELISA).


K1 antibody is used to detect dsRNA in MEFs treated with poly I:C (lower panel). Presence of dsRNA is concomitant with phosphorylation of eIF2a and thus protein synthesis arrest (upper panel). Figure taken from Clavarino et al.(2012) PLoS Pathog 8:e1002708.