The properties and interactions of the isolated α- and β-chains of human haemoglobin: IV. Immunological studies involving antibodies against the isolated chains

Antibodies against the isolated α- and β-chains of human haemoglobin produce precipitation and complement fixation with their antigens. Both types of antibody give complement fixation with haemoglobin A, but do not cross-react with the opposite type of chain. The behaviour of the anti α- and anti β-sera is not affected by the presence of p-mercuribenzoate in the immunizing antigen. The reaction of the anti α-serum with free α-chains is the same as with α-chains in native haemoglobin; however, when the accompanying β-chains are replaced by those of another species in hybrids, or by γ-chains in foetal haemoglobin, the strength of the reaction of the anti α-serum is reduced in a specific way. The reaction of anti β-serum with free β-chains is much stronger than when the β-chains are combined with α-chains in native haemoglobin; however, replacement of the α-chains by those of another species in hybrids, or by mutant α-chains in haemoglobin Burlington, has no effect. After anti β-serum has been absorbed by haemoglobin A, it is still capable of giving complement fixation with free β-chains. This shows the presence of an anti β-antibody specific to the free β-chains. The anti α- and anti β-sera are both highly sensitive to even one residue substitution in the chains against which they are directed.