Table 1.
The ability of monoclonal aPL to bind native antigens.
| Heavy chain | Position 96 | Position 97 | Position 100 | Position 100g | Light chain | CL | β2GPI | Native DI |
|---|---|---|---|---|---|---|---|---|
| IS4VH | R | R | R | R | IS4VL | ++ | + | + |
| IS4VHi&ii | S | S | R | R | IS4VL | + | − | + |
| IS4VHiii | R | R | S | R | IS4VL | + | + | + |
| IS4VHiv | R | R | R | S | IS4VL | + | + | + |
| IS4VHiii&iv | R | R | S | S | IS4VL | − | − | − |
| IS4VHx | S | S | S | S | IS4VL | − | − | − |
| IS4VH | R | R | R | R | B3VL | ++++ | ++ | ++ |
| IS4VHi&ii | S | S | R | R | B3VL | +++ | + | + |
| IS4VHiii&iv | R | R | S | S | B3VL | +++ | + | + |
| IS4VHx | S | S | S | S | B3VL | + | − | + |
A panel of 10 monoclonal aPL, all comprised of native or mutated IS4VH paired with either IS4VL or B3VL, were tested against CL, β2GPI, and native DI. Variants of IS4VH are named using Roman numerals to represent positions at which arginine (R) residues in IS4VHCDR3 have been replaced by serine (S) as indicated. Each VH/VL combination was tested at 500 ng/ml in triplicate and the degree of binding was defined from the mean absorbance as follows: −, OD < 0.1; +, OD 0.1–<0.4; ++, OD 0.4–<0.8; +++, OD 0.8–<1.2; and ++++, OD ≥ 1.2. CL and β2GPI binding has previously been described in full (Giles et al., 2006). Abbreviations: β2GPI, beta 2 glycoprotein I; CDR, complementarity determining region; CL, cardiolipin; DI, Domain I of β2GPI; VH, variable heavy chain sequence; VL, variable light chain sequence.