Partial characterization of human histaminopectic factor

Sera from normal human subjects are pooled and fractions are isolated by salt precipitation. The fraction responsible for agglutinating histamine bound latex particles is further purified by column chromatography. The histaminopectic activity can thus be traced to a single protein present in the IgG fraction of normal human serum. Its absence or the presence of an inhibitor in serum from allergic subjects is also sought as well as correlations between plasma concentrations of known immunoglobulins and specific histaminopectic activity. Some of its physical-chemical properties are explored. Evidence was also presented pointing to the possible presence of an inhibitor of the histaminopectic factor in human atopic serum.