Structure/functions

Normal immune cells

Cancer cells

Expression of antigen receptors

I. Immunoglobulins are expressed by B cells

II. T cell receptors are expressed by T cells

Both antigen receptors are expressed by cancer cells and are of a single clone

Class switching of immunoglobulins

Yes. In B cells

No

Hypermutation of variable regions

of immunoglobulins

High frequency

Low frequency

Glycosylation patterns (unique)

No O-linked glycosylation and only one N-linked glycosylation at N297 position of IgG heavy chains; terminal NeuAc only (not

Both O-linked and N-linked glycans are detected in cancerous IgG heavy chains with terminal NewAc and NuGc (O-linked glycan recognized by RP215 Mab

Interactions with TLRs (based on gene expression studies)

No known interactions with TLRs

Strong interaction with TLRs within cancer cells

Relative immunoactivity

Normal immunoactivity

Weak immunoactivity (less than 1% - 5%) due to aberrant glycosylations

Function assays (apoptosis and CDC reactions)

No known effect

Induced apoptosis and CDC reactions by RP215 and anti-antigen receptors (in vivo nude mouse models)